Title of Invention	A BRAKE CYLINDER DEVICE
Abstract	The brake cylinder device of the present invention is provided with a normal brake means, a spring brake means, a push rod, and a projected length adjusting means having a guide member, which is movable together with the push rod and attached to the push rod in such a manner that a predetermined resisting force is applied at movement of the push rod, thereby adjusting a projected length from a cylinder main body of the push rod. The projected length adjusting means is additionally provided with a recess installed on a guide member and a regulating means having an engaging portion to be engaged with the recess and placed between the second piston and the first spring to regulate a movable range in a direction in which the first piston of the guide member moves.

Title of Invention

A BRAKE CYLINDER DEVICE

Abstract

The brake cylinder device of the present invention is provided with a normal brake means, a spring brake means, a push rod, and a projected length adjusting means having a guide member, which is movable together with the push rod and attached to the push rod in such a manner that a predetermined resisting force is applied at movement of the push rod, thereby adjusting a projected length from a cylinder main body of the push rod. The projected length adjusting means is additionally provided with a recess installed on a guide member and a regulating means having an engaging portion to be engaged with the recess and placed between the second piston and the first spring to regulate a movable range in a direction in which the first piston of the guide member moves.

Full Text	BRAKE CYLINDER DEVICE AND BRAKE CALIPER DEVICE CROSS REFERENCE TO RELATED APPLICATION [0001] The present invention is an application for claiming the right of priority on the basis of the Japanese Patent Application No. 2007-104970 (filed on April 12, 2007). BACKGROUND OF THE INVENTION 1 Field of the Invention [0002] The present invention relates to a brake cylinder device provided with a push rod for actuating a brake mechanism for vehicles and capable of automatically adjusting the projected length of the push rod from a cylinder main body at braking operation, and a brake caliper device provided with the brake cylinder device. 2 Description of Related Art [0003] As for a brake cylinder device capable of automatically adjusting the projected length of a push rod from a cylinder main body, Patent Document 1 (Japanese Published Examined Patent Application No. H6-67725 (claim 1, Fig. 2), has disclosed a constitution, which is provided with an output piston having inside a cylinder a push rod connected to a brake shoe for braking a wheel tread and a friction ring assembly made so as to increase a friction/sliding resistance.to the inner surface of a cylinder by holding one elastic ring between two circular plates to expand radially and outwardly. Patent Document 1 has described that when the brake shoe wears while the brakes are in operation, an output piston and a friction ring assembly move according to an amount of water, whereas the friction ring assembly will not move due to a greater sliding resistance when the brakes are loosened, as a result, there is secured a proper clearance between the brake shoe and the wheel tread. Then, Patent Document 1 has also described a constitution in which a nut is used to attach a stepped shaft to the center of the friction ring assembly, an end plate is fixed on one end surface of the output piston by using fitting screws, and a release spring is placed between a. flange formed at one end of the stepped shaft and the end plate. It has also described that a relative momentum between the output piston and the friction ring assembly is restricted so as not to exceed a predetermined clearance. [0004] Further, as a brake mechanism for railway vehicles, Patent Document 2 (Japanese Published Unexamined Patent Application No. S63-125834) has disclosed a constitution of a brake cylinder device having both a normal brake means used in a normal operation and actuated by pressure air as well as a spring brake means used in a prolonged parking and actuated by spring force even in the absence of pressure air. [0005] Regarding a brake cylinder device having both the normal brake means and the spring brake means such as that disclosed in Patent Document 2, such an idea has been proposed that, as shown as disclosed in Patent Document 1, there is provided a projected length adjusting means capable of adjusting automatically the projected length of a push rod from a cylinder main body when the brakes are in operation, thereby improving the convenience as a brake cylinder device. [0006] However, Patent Document 1 has disclosed only an embodiment having a friction ring assembly as the above-described projected length adjust ing means and disclosed only a special constitution having a stepped shaft or the like corresponding to a projected length adjusting means by using a friction ring assembly as means for regulating a relative momentum between a push rod-equipped output piston and the friction ring assembly. Therefore, if the projected length adjusting means disclosed in Patent Document 1 is incorporated into a brake cylinder device having both a normal brake means and a spring brake means, the brake cylinder device is complicated in mechanism and enlarged. As such, a brake cylinder device having a normal brake means and a spring brake means has a difficulty in realizing means for regulating a range where the projected length of a push rod is adjusted and a range where it is not adjusted in the projected length adjusting means by using the special constitution disclosed in Patent Document 1. SUMMARY OF THE INVENTION [0007] The present invention has been made in view of the above-described situation, an object of which is to provide a brake cylinder device having a normal brake means, a spring brake means and means for adjusting the projected length of a push rod, capable of preventing the device from being complicated in mechanism or increased in size and also capable of realizing means for regulating a range where the projected length of the push rod is adjusted and a range where it is not adjusted by using a simple mechanism as well as a brake caliper device equipped with the brake cylinder device. [0008] The brake cylinder device according to the first invention for attaining the above object is a brake cylinder device used in a brake mechanism for vehicles, which is provided with a normal brake means having a first piston in which an urging force of a first spring acts reversely on the pressure from a first pressure chamber, wherein a pressurized fluid is fed to the first pressure chamber, thereby the.first piston moves relatively with respect to the cylinder main body against the urging force of the first spring andmoves in a braking direction, a push rod, which is movable together with the first piston, projected length adjusting means having a guide member, which is movable together with the push rod and attached to the push rod in such a manner that a predetermined resisting force is applied when the push rod makes a relative movement parallel with a direction in which the first piston moves, wherein adjusted is a projected length of the push rod from the cylinder main body at release of the brakes in a direction in which the first piston moves, and a spring brake means having a second piston in which an urging force of the second spring acts reversely on the pressure from the second pressure chamber and the push rod penetrates therethrough, wherein a state of feeding a pressurized fluid to the second pressure chamber is shifted to a state of discharging it, thereby the second piston is moved in the braking direction by the urging force of the second spring and the push rod is also urged via the normal brake means, wherein the projected length adjusting means is provided with a recess or a projection installed on the guide member and also a regulating means having an engaging portion to be engaged with the recess or the projection and placed between the second piston and the first spring, thus regulating a movable range of the guide member in a direction in which the first piston moves. [0009] According to the present invention, such a constitution is provided that the push rod, which moves together with the first piston of the normal brake means, penetrates through the second piston of the spring brake means and a predetermined resisting force acts between the push rod and the guide member of the projected length adjusting means. Therefore, a brake cylinder device having the normal brake means, the spring brake means and the projected length adjusting means can be made compact by preventing the device from being complicated in mechanism and enlarged. Then, the projected length adjusting means is provided with a simply-structured regulating means, which is placed between the second piston and the first spring and equipped with an engaging portion making an engagement with a recess or a projection installed on the guide member, thereby regulating a movable range of the guide member. Therefore, it is possible to regulate a range where the projected length of the push rod is adjusted and a range where it is not adjusted by using a simple structure. As a result, the present invention can provide a brake cylinder device having a normal brake means, a spring brake means and an adjusting means for the projected length of the push rod, which can prevent the device from being complicated in mechanism and enlarged and also realize means for regulating a range where the projected length of the push rod is adjusted and a range where it is not adjusted by using a simple constitution. [0010] The brake cylinder device according to the second invention is the brake cylinder device according to the first invention, in which the regulatingmeans also regulates amovable range of the guide member in the rotating direction around the central axis of the first piston by engagement of the engaging portion with the recess or the projection. [0011] According to the above constitution, the recess or the projection and the regulating means having an engaging portion to be engaged with the recess or the projection are used to function as a detent for the guide member as well. It is, therefore, possible to realize not only the function of regulating a movable range in a direction in which the first piston of the guide member moves but also the function as a detent by using one regulating means, thus making the brake cylinder device simple in mechanism. [0012] The brake cylinder device according to the third invention is the brake cylinder device according to the first invention or the second invention, wherein the recess or the projection is installed at a plurality of places on the guide member, and the engaging portion is also installed at a plurality of places on the regulating means corresponding individually to each of the recesses or the projections. [0013] According to the present invention, a plurality of the corresponding recesses or projections and the engaging portions are installed, by which loads acting on mutually engaging parts can be dispersed to reduce wear, which occurs at the recesses or projections and the engaging portions . Therefore, the brake cylinder device is improved in durability. [0014] The brake cylinder device according to the fourth invention is the brake cylinder device according to any one of the first invention to the third invention, wherein the regulating means is installed as a partition for separating a region where the.normal brake means is placed from a region where the spring brake means is placed inside the cylinder main body, an opening portion through which the guide member penetrates is formed at the center of the partition, the engaging portion is installed at an edge forming the opening portion, the opening portion is formed in such dimensions that allows a clearance covering the entire circumference to exist between an outer diameter of the guide member and an edge of the opening portion so that the guide member can penetrate through the opening portion without making an engagement of the recess or the projection with the engaging portion at assembly of the brake cylinder device. [0015] According to the present, invention, the regulating means is installed as a partition for separating a region of the normal brake means from that of the spring brake means, thus making it possible to form the regulating means in a thin flat-plate shape and also simplify the constitution. Thus, the simply constituted regulating means can be placed so as to attain an effective use of space in a brake cylinder device. Then, at assembly of the brake cylinder device, a guide member can penetrate through an opening portion of the partition via a predetermined clearance without engagement of the recess or the projection with the engaging portion. Therefore, the assembly can be conducted easily and with an increased efficiency. [0016] The brake cylinder device according to the fifth invention is the brake cylinder device according to any one of the first invention to the fourth invention, wherein the partition and the guide member are placed in such a manner that a radial center position of the guide member is eccentric to that of the opening portion. [0017] According to the present invention, the center of the guide member is made eccentric to the center of the opening portion, thus making it possible to provide In a simple manner such a constitution that a guide member can penetrate through an opening portion of the partition via a predetermined clearance without engagement of the recess or the projection with the engaging portion at assembly of the brake cylinder device. [0018] The brake cylinder device according to the sixth invention is the brake cylinder device according to any one of the first invention to the fifth invention, wherein the projected length adj ust ing means is additionally provided with an uneven surface formed by repeatedly arranging recesses and projections on an outer surface of the push rod in a direction in which the push rod moves and an elastic member placed between the push rod and the guide member, the elastic member is deformed and engaged with the uneven surface, by which the guide member is connected with the push rod, and when a force greater than a predetermined value is applied to the guide member, the elastic member is deformed to ride over a proj ection of the uneven surf ace, thereby the push rod is displaced with respect to the guide member. [0019] Conventionally, according to the constitution described in Patent Document 1, for example, only a frictional force between the inner circumferential surface of a flat cylinder and the surface of an elastic ring is used to generate a sliding resistance, thereby the sliding resistance of the friction ring assembly is easily made unstable by the surface condition and wear of the inner circumferential surface of the cylinder or the wear of the surf ace of the elastic ring. Further, adjustment is made by using a adjusting screw, which may complicate the adjustment and control of the sliding resistance. However, according to the present invention, the elastic member is deformed and engaged (cut into), thus making it possible to stabilize a frictional force or a binding force between the push rod and the guide member. Thereby, it is possible to adjust and control the sliding resistance by a simple constitution. [0020] The brake cylinder device according to the seventh invention is the brake cylinder device according to any one of the first invention to the sixth invention, wherein the projected length adjusting means is additionally provided with a shaft rod, which moves together with the first piston and to which the push rod is attached, the push rod is formed in a cylindrical shape having a shaft hole extending parallel with a direction in which the first piston moves, a female thread is made at least at a part of the. inner surface of the shaft hole, and a male thread to be screwed with the female thread is made at least at a part of the outer surface of the shaft rod, which is screwed into the shaft hole. [0021] According to the present invention, since the push rod is attached by being screwed With the shaft rod moving together with the first piston, it is possible to provide such a constitution that a projected length portion of the push rod is absorbed by a screw movement made by the shaft rod with respect to the push rod. Therefore, it is possible to provide such constitutions so as to prevent a positional deviation of the first piston with respect to a cylinder main body also in a state that the projected length of the push rod is adjusted, thereby retaining the capacity of the first pressure chamber substantially at a constant level. [0022] The brake cylinder device according to the eighth invention is the brake cylinder device according to any one of the first invention to the seventh invention, wherein the projected length adjusting means is placed between the guide member arranged around the push rod and the second piston, additionally provided with an outer cylinder member internally having the guide member and moving together with the first piston, and the second piston is locked with the outer cylinder member when movement of the second piston in the braking direction occurs, by which the spring brake means urges the push rod via the outer cylinder member and the first piston of the normal brake means. [0023] According to the present invention, the second piston is locked with an outer cylinder member, which is arranged between the guide member and the second piston to move together with the first piston, thus making it possible to urge the push rod. Therefore, the outer cylinder member constituted in a simple shape is placed, thereby providing in a simple mechanism such a constitution that the push rod is urged via the normal brake means when movement of the second piston in the braking direction occurs. [0024] Further, as another view of the invention, it is possible to constitute an invention of a brake caliper device having any one of the above-described brake cylinder devices. In other words, the brake caliper device according to the ninth invention is provided with the brake cylinder device according to any one of the first invention to the eighth invention and a caliper body having the brake cylinder device and attached so as to make a relative movement in a shaft direction with respect to truck wheels, and the brake cylinder device is actuated, by which a disc on the shaft is held between a pair of brake shoes attached to the caliper body, thus generating a braking force. [0025] According to the present invention, it is possible to provide a brake caliper device, which is provided with a brake cylinder device having a normal brake means, a spring brake means and means for adjusting the projected length of a push rod, preventing the device from being complicated in mechanism and enlarged, and making it possible to realize means for regulating a range where the projected length of the push rod is adjusted and a range where it is not adjusted by using a simple mechanism. [0026] The brake caliper device according to the tenth invention is the brake caliper device of the ninth invention, wherein the caliper body is attached to the truck via a swinging pin so as to swing axially or parallel with a direction in which a vehicle advances, the brake cylinder device installed on the brake caliper device is provided on the cylinder main body with a first pressurized fluid channel communicated to the first pressure chamber and a second pressurized fluid channel communicated to the second pressure chamber, a first feed/discharge port opened from the first pressurized fluid channel to the outside of the cylinder main body for feeding and discharging a pressurized fluid and a second feed/discharge port opened from the second pressurized fluid channel to the outside of the cylinder main body for feeding and discharging the pressurized fluid are respectively placed so as to be positioned in a perpendicular direction with respect to the swinging pin. [0027] According to the present invention, since the first feed/discharge port and the second feed/discharge port are positioned below the swinging pin in a perpendicular direction, it is possible to prevent the caliper body and the brake cylinder device from having a momentum in a swinging direction both when feeding a pressurized fluid via the first feed/discharge port to the first pressure chamber and when feeding the pressurized fluid via the second feed/discharge port to the second pressure chamber. Therefore, it is possible to prevent a localized contact of a brake shoe on a disc and also a localized wear of the brake shoe in an emergency of the pressurized fluid. [0028] The brake caliper device according to the eleventh invention is the brake caliper device of the ninth invention, wherein the brake cylinder device installed on the brake caliper device is provided with a ventilation tube formed as a cylindrical elastic body and attached to the cylinder main body by being screwed with a thread portion installed on the outer, circumference of one end thereof, thereby communicating with the interior of the cylinder main body, and a filter made of a rigid body and arranged at a position, which is inside the ventilation tube and corresponding to a part where the thread portion is formed on the ventilation tube. [0029] According to the present invention, it is possible to attach the filter together with the ventilation tube only by screwing the ventilation tube on which the filter is installed into the cylinder main body at the thread portion 75a at the end thereof. Then, the filter is placed inside the ventilation tube, thereby eliminating the necessity for providing a member or the like especially intended for attaching the filter. Therefore, it is possible to attach the filter and the ventilation tube to the cylinder main body easily and quickly and also perform work for attaching the filter in a simplified manner. [0030] . The brake caliper device according to the twelfth invention is the brake caliper device of the ninth invention, wherein the caliper body is provided with a pair of brake levers, one end of which is actuated by the brake cylinder device installed on the brake caliper device, and also provided with a pair of brake-shoe retaining portions respectively attached to the other end of the pair of brake levers to retain the brake shoe and a leg projected on the lower end of the brake-shoe retaining portion. [0031] According to the present invention, the leg is appropriately set for the dimensions when the brake caliper device is removed and arranged on a floor or the like for maintenance work of the brake caliper device, thus making it possible to keep the brake caliper device horizontal on the basis of the lower end on one end of the caliper body and the leg. It is, therefore, possible to easily perform the maintenance work or the like, thereby improving the work efficiency. [0032] The brake caliper device according to the thirteenth invention is the brake caliper device of the ninth invention, wherein the caliper body is provided with a pair of brake levers, one end of which is actuated by the brake cylinder device installed on the brake caliper device, and also provided with a pair of brake-shoe retaining portions respectively attached to the other ends of the pair of brake levers to retain the brake shoe and a brake-shoe attaching structure for attaching the brake shoe to the brake-shoe retaining portion, the brake-shoe retaining portion is provided with a key groove formed in such a manner that a key portion formed on the brake shoe to be attached and detached runs along downward in a perpendicular direction, the brake-shoe attaching structure is provided with a latch supported so as to swing below the brake-shoe retaining portion, urged by a spring to the axial direction and locked with the key portion, thereby supporting the brake shoe, a snap pin inserted below the brake-shoe retaining portion to regulate the latch swung in a direction in which the brake shoe is unlocked from the latch, and a coupling chain for coupling the latch with the snap pin. [0033] According to the present invention, such a structure is provided that the brake shoe can be easily attached or detached by using a latch urged by a spring (for example, a flat spring) in a direction different from that in which the brake shoe is attached or detached. Then, it is possible to prevent the latch from being unlocked only by inserting the snap pin below the brake-shoe retaining portion. In other words, in performing work of exchanging the brake shoe, the snap pin is removed, thereby allowing the latch to be unlocked, the latch is turned against the flat spring or the like, with a possible drop of the brake shoe taken into account, thus making it possible to securely remove the brake shoe. Then, even at attachment of a new brake shoe, the latch is locked by the flat spring or the like at a stage where the key portion of the brake shoe is allowed to slide on the key groove of the brake-shoe retaining portion and arrives at a predetermined position. Therefore, the new brake shoe can be easily attached. Further, the latch is coupled with the snap pin by using a coupling chain, thereby easily providing a constitution for preventing the removal or loss of the snap pin. As a result, a brake caliper device is provided, which is free of an inadvertent drop of the brake shoe, realizing work of exchanging the brake shoe easily so that support only by the brake shoe can be released at any time, and also eliminating the necessity for troublesome and skilled work in tightening bolts by using a bundling wire in attaching the brake shoe. BRIEF DESCRIPTION OF THE DRAWINGS Other and further objects, features and advantages of the invention will appear more fully from the following description taken in connection with the accompanying drawings in which: Fig. 1 is a schematic diagram of a brake caliper device for railway vehicles related to an embodiment of the present invention, when viewed axially. Fig. 2 is a schematic diagram of the brake caliper device given in Fig. 1, when viewed from a brake cylinder device parallel with a direction in which a vehicle advances. Fig. 3 is a schematic diagram of the brake caliper device given in Fig. 1, when viewed from below. Fig. 4 is a perspective view of a brake pad used in the brake caliper device given in Fig. 1. Fig. 5 covers a plan view of the brake pad given in Fig. 4 and a sectional view of the brake pad indicated by the arrow A to A.. Fig. 6 is a sectional view of the brake cylinder device used in the brake caliper device given in Fig. 1. Fig. 7 is a drawing including a partial sectional view showing a partition of the brake caliper device and a guide member of the outer cylinder member given in Fig. 6. Fig. 8 is a drawing of a manual opening mechanism used in the brake caliper device given in Fig. 6. Fig. 9 is a sectional view, which shows a plurality of different cross sections covering only half the;cross section of the brake cylinder device given in Fig. 6, which is divided at the center of the shaft. Fig. 10 is an enlarged sectional view showing a ventilation tube of the brake cylinder device given in Fig. 9 and the vicinity thereof. Fig. 11 covers a front elevational view.and a side view of a filter arranged inside the ventilation tube given in Fig. 10. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0034] Hereinafter, an explanation will be made for executing the best mode of the present invention by referring to the drawings. In addition, a brake cylinder device and a brake caliper device having the brake cylinder device related to embodiments of the present invention will be explained by exemplifying a case where they are used as a brake mechanism for railway vehicles. Constituents of each drawing are depicted at an accuracy corresponding to that used in a design drawing. [0035] Fig. 1 is a schematic diagram of a brake caliper device 1 for railway vehicles related to an embodiment of the present invention, when viewed axially. Fig. 2 is a schematic diagram of the brake caliper device 1 given in Fig. 1, when viewed from a brake cylinder device 2 parallel with a direction in which a vehicle advances. Fig. 3 is a schematic diagram of the brake caliper device 1 given in Fig. 1, when viewed from below. As shown in Fig. 1 to Fig. 3, the brake caliper device 1 of the present embodiment is a disc brake-type brake mechanism. [0036] The brake caliper device 1 shown in Fig. 1 to Fig. 3 is provided with a brake cylinder device 2, a caliper body 11 equipped with the brake cylinder device 2 and attached so as to make a relative movement axially with respect to a vehicle truck 100, a pair of backplates (brake-shoe retaining portions) 12, 12 for retaining respectively a pair of brake pads (brake shoes) 14, 14, a pair of brake-shoe attaching structures 13, 13 for attaching respectively the brake pads 14, 14 to the pair of back plates 12, 12, a leg 18 placed below the back plate 12, and a parallel guiding mechanism 23 placed below the caliper body 11. [0037] The brake caliper device 1 is designed to generate a braking force by holding a circular plate-like brake disc 15, which is a disc on the shaft rotating in association with rotating wheels of a railway vehicle (not illustrated) , between the pair of brake pads 14, 1.4 attached to the caliper body 11 via the back plate 12, upon actuation of the brake cylinder device 2. In other words, the brake disc 15 is formed in a circular plate shape having front/back braking surfaces 15a, 15a formed so as to be orthogonal to the rotational shaft, the brake cylinder device 2 is actuated, by which the brake pads 14, 14 are pressed so as to hold the brake disc 15 between both sides thereof with respect to the braking surfaces 15a, 15a from a direction substantially parallel with a direction of the rotating shaft of the brake disc 15 (a direction perpendicular to the space in Fig. 1). . [0038] As shown in Fig. 1 to Fig. 3, the caliper body 11 is provided with a binding member 16 and a pair of brake levers 17, 17. The binding member 16 is attached to a bracket 100a fixed on the bottom of a truck via a swinging pin 16a so as to swing around the shaft parallel with a direction in which a vehicle advances. Then, a pair of brake levers 17, 17 are mounted so as to swing via a pair of fulcrum pins 17a approximately symmetrical to the binding member 16. The fulcrum pin 17a is mounted so as to extend toward a perpendicular direction, when viewed from the top, with respect to an axial direction of the swinging pin 16a. [0039] The pair of brake levers 17, 17 are constituted so that one end thereof is provided with a brake cylinder device 2 via a cylinder support pin 12a and driven by the brake cylinder device 2 . Then, the pair of brake levers 17, 17 are respectively provided with a pair of back plates 12, 12 for retaining the brake pad 14 on the other end via the fulcrum pin 17a with respect to one end to which the brake cylinder device 2 is attached. The back plate 12 is attached, to the brake lever 17 so as to swing via the support pin 12a extending parallel with the fulcrum pin 17a. Further, a leg 18 installed so as to project in a rectangular solid shape is providedbelow each of the backplates 12. The leg 18 is designed for the projected length so as to correspond in dimensions to the lower end of the cylinder support pin 17b, with consideration given in such a manner that the end of the leg 18 and the lower end of the cylinder support pin 17b are arranged on a plane, which is substantially parallel. Therefore, when the brake caliper device 1 is removed from a truck 100 and placed on a horizontal floor or the like in performing maintenance work or the like, the end of the leg 18 and the lower end of the cylinder support pin 17b are placed on the ground, thus making it possible to mount horizontally the brake caliper device 1. [0040] Fig. 4 is a perspective view of the brake pad 14, an'd Fig. 5 covers a plan view of the brake pad 14 (Fig. 5 (a) ) and a sectional view indicated by the arrow A to A thereof (Fig. 5 (b) ) . As shown in Fig. 3 and Fig. 4, the brake pad 14 is formed so as to substantially run along a part of the circular arc of the brake disc 15, and a key portion 14a is formed on the side opposite to a surface in contact with the brake disc 15. Then, as clearly shown in Fig. 5, the back plate 12 is provided with a key groove 12b formed in a shape substantially in agreement with an outer shape of the key portion 14a in such a manner that the key portion 14a of the key pad 14 to be attached or detached runs along downward in a perpendicular direction. Thereby, a brake pad 14 is attached to the back plate 12 in such a manner that the key portion 14a is fitted into the key groove 12b, while sliding thereon. [0041] As clearly shown in Fig. land Fig. 3, abrake-shoe attaching structure 13, which is to attach to the back plate 12 the brake pad 14 kept in a state that the key portion 14a is fitted into the key groove 12b, is installed below the back plate 12. The brake-shoe attaching structure 13 is provided with a latch 19, a snap pin 20, a coupling chain 21 and others. [0042] The latch 19 is a narrow flat plate-like member arranged on a surface perpendicular to the brake disc 15 and supported pivotally so that one end thereof can swing below the back plate 12 via a pin (not illustrated) . Further, as clearly shown in Fig. 3, a projected portion 19a shaped so as to be substantially fitted into the key groove 12b is formed on the side facing to the brake pad 14 of the latch 19, and the projected portion 19a is in contact with the lower end surface of the key portion 14a, thereby preventing the brake pad 14 from falling down. Then, the end 19b on the other end of the latch 19 is pulled outwardly (in a direction opposite to the brake disc 15), by which the projected portion 19a of the latch 19 is unlocked from the key portion 14a of. the brake pad 14. Further, the latch 19 is urged axially by a flat spring 22 supported on the leg 18 in a cantilever manner on the same side as that supported pivotally so as to swing, thereby locking in the key portion 14a to support the brake pad 14. [0043] As clearly shown in Fig. 1 and Fig. 3, the snap pin 20 is formed by procedures in which one piece of a rigid wire rod is bent in a coil shape approximately one and half times to form a spring portion 20a, and only one end of the spring portion 20a is thereafter bent in a wave shape to form a curved portion 20b. Further, a linear portion 20c is installed on the other end in which the curved portion 20b of the snap pin 20 is not formed. The linear portion 20c is inserted into a pin hole made below the back plate 12, and the snap pin 20 is inserted into the back plate 12 so that the curved portion 20b is also fitted into a groove portion provided below the back plate 12. With such a constitution, when the snap pin 20 is inserted into the back plate 12 in a state that the latch 19 is locked with the brake pad 14, the latch 19 is to be positioned so as to be held between the curved portion 20b and the linear portion 20c. Thereby, the snap pin 20 is inserted below the back plate 12, thus regulating the latch swung in a direction in which the brake pad 14 is unlocked from the latch 19, and preventing the brake pad 14 from being unlocked from the latch 19. [0044] The snap pin 20 is attached to the latch 19 by a coupling chain 21 installed so as to couple the snap pin 20 with the latch 19. That is, one end of the coupling chain 21 is fixed, for example, by being bound to one site of the latch 19, whereas . the other end thereof is attached to the spring portion 20a of the snap pin 20. The snap pin 20 is required to be removed at every exchange of the brake pad 14. Further, the snap pin, which is small and easily lost, can be easily made loss-preventive when having a coupling chain 21. The coupling chain 21 is a flexible continuous body and may include any type of thread as long as they are not likely to break after prolonged use, for example, wire and resin threads ##wire?##. [0045] As clearly shown in Fig. 1 and Fig. 3, the parallel guiding mechanism 23 is provided with a pair of guide members 24a, 24b and a pair of guide rods 25a, 25b. The guide members 24a, 24b are respectively provided with a U-shaped curved portion, with one end thereof fixed to the back plate 12. Then, one end of the guide rod 25a is fixed to the other end of the guide member 24a, whereas the. other end of the guide rod 25a is fitted into a through-hole formed on the other end of the guide member 24b in a loosely fitted state. In a similar manner, one end of the guide rod 25b is fixed to the other end of the guide member 24b, whereas the other end of the guide rod 25b is fitted into a through-hole formed on the other end of the guide member 24a in a loosely fitted state. Further, the guide rod 25a and the guide rod 25b are arranged parallel with each other. When the brake cylinder device 2 is actuated by a parallel guiding mechanism 23 composed of the pair of guide members 24a, 24b and the guide rods 25a, 25b and the brake lever 17 is swung to move in a direction in which a pair of brake pads 14, 14 come closer together with the back plate 12 (a direction in contact with the brake disc 15), the pair of brake pads 14, 14 are guided so as to conduct approximately symmetrical motions, with the brake disc 15 held therebetween. [0046] In the above-described brake caliper device 1, as will be described later, the cylinder main body 26 of the brake cylinder device 2 is attached to one end of the brake lever 17, whereas the push rod 28 is attached to the other end of the brake lever 17, and the brake cylinder device 2 is operated to project or retract the push rod 28. Thereby, the vicinity of the cylinder support pin 17b for a pair of brake levers 17, 17 is driven so as to space away from or come closer to each other. Therefore, the pair of brake levers 17, 17 act on the basis of the fulcrum pin 17a in such a manner so as to hold the brake disc 15 between the brake pads 14. At this time, in the pair of brake levers 17, 17, the brake pad 14 installed on one end of the brake lever 17 is in contact with the braking surface 15a of the brake disc 15 earlier. Then, the other brake lever 17 utilizes a reaction force received from the brake pad 14 in contact with the braking surface 15a, thereby pressing the brake pad 14 on the braking surface 15a of the brake disc 15. Therefore, the brake disc 15 is held between the pair of brake pads 14, 14, and a frictional force generated between the brake pads 14, 14 and the braking surfaces 15a, 15a is used to brake the rotation of the brake disc 15 and also the rotation of wheels of a railway vehicle installed coaxially with the brake disc 15. [0047] Next, an explanation will be made in detail for a brake cylinder device 2 of the present invention. The both ends of the brake cylinder device 2 are respectively coupled with cylinder support pins 17b in the braking direction. Then, as shown in Fig. 6, which is a sectional view of the brake cylinder device 2, the brake cylinder device 2 is provided with a cylinder main body 2 6, a normal brake means 27, a push rod 28, a spring brake means 29, a proj ected length adjusting means 30 and others . [0048] The cylinder main body 26 is constituted with a first casing portion 31 and a second casing portion 32 to form an inner space 26a. Constitutions such as the normal brake means 27, the push rod 28, the spring brake means 29, and the projected length adjusting means are arranged in such a manner that some or all of them can be accommodated in the inner space 2 6a. Further, the first casing portion 31 is provided with a bottom and formed approximately in a cup shape (cylindrical shape), and the second casing portion 32 is fixed by using a bolt 33 so as to close an opened side of the first casing portion 31. Thereby, the inner space 26a is formed. Further, the end of the first casing portion 31 is coupled with the brake lever 17 by the cylinder support pin 17b. [0049] The normal brake means 27 is primarily constituted with a first spring 34, a first pressure chamber 35, and a first piston 36. The first piston 36 is arranged so as to separate, the inner space 26a, fitted hermetically into the inner circumferential surface of the first casing portion 31 and also arranged so as to slide axially on the first casing portion 31. The first pressure chamber 35 is constituted with spaces partitioned by the first piston 36 and the first casing portion 31. A cup packing 38 is adhered on the first piston 36 in order to improve the hermetic state of the first pressure chamber 35. Then, the cylinder main body 26 is provided with a first pressurized fluid channel 37 communicated to the first pressure chamber 35, and compressed air as a pressurized fluid, which is a working fluid, is fed via the first pressurized fluid channel 37 to the first pressure chamber 35. In addition, a first feed/discharge port 37a, which is opened from the first pressurized fluid channel 37 to the outside of the cylinder main body 26 and to which the compressed air is fed and discharged, is arranged so as to position below a swinging pin 16a (refer to Fig. 1 and Fig. 2) in a perpendicular direction. [0050] Further, the first spring 34 is arranged on the inner space 26a opposite to the first pressure chamber 35 via the first piston 36 and placed so as to urge the first piston 36 toward the first pressure chamber 35. According to the above constitution, an urging force of the first spring 34 and the pressure from the first pressure chamber 35 act on the first piston 36 reversely, compressed air is fed to the first pressure chamber 35, by which the first piston 36 makes a relative movement with respect to the cylinder main body 26 against the urging force of the first spring 34, and the normal brake means 27 moves in the braking direction (a direction indicated by the arrow A in Fig. 6). [0051] The push rod 28 is formed in a cylindrical shape having a shaft hole extending parallel with a direction in which the first piston 36 moves, and a female thread 39 is made in the vicinity of the end of the first pressure chamber 35 on the inner circumferential surface of the shaft hole. Further, the push rod 28 is provided on the outer circumferential surface with an uneven surface 4 0 f ormedby repeatedly arranging recesses and projections in a direction in which the push rod 28 moves. In addition, a difference in height of the recesses and projections on the uneven surface 40 is, for example, about 0.3 mm. The uneven surface 40 is a part of the constitution forming the projected length adjusting means 30. Further, the cylinder support pin 17b of the brake lever 17 is coupled with the leading end of the push rod 28 via a coupling member 41, thus making it possible to transmit a driving force of the brake cylinder device 2 to the brake lever 17 of the caliper body 11. In addition, the coupling member 41 is fixed to the push rod 28 by using a pin or the like in order to prevent a relative axial rotation. Further, there is mounted a flexible bellows-like cover 46 for dust prevention between the push rod 28 and the second casing portion 32 in such a manner so as to cover an opening portion formed on the end opposite to first casing portion 31 of the second casing portion 32 . In addition, the push rod 28 is installed so as to move together with the first piston 36 via the projected length adjusting means 30, which will be described later. [0052] The spring brake means 29 is primarily constituted with a second spring 42, a second pressure chamber 43 and a second piston 44. The second piston 44 is constituted with a cylindrical portion 44a formed as a cylindrical body, flange-like portions 44b, 44c installed so as to project outwardly respectively on both ends of the cylindrical portion 44a, a cylindrical member 44d placed inside the cylindrical portion 44a and others, with the push rod 28 arranged so as to penetrate through the cylindrical portion 4 4a . In addition, the flange-like portion 44b is constituted with a plurality of members and arranged at the leading end of the push rod 28, whereas the flange-like portion 44c is usually arranged on the first piston 36 . The cylindrical member 44d is integrated with the cylindrical portion 44a and the flange-like portions 44b, 44c by a fixing ring 67 to be described later. Further, the second casing portion 32 is provided with a spring seat 32a, which is projected inwardly along the inner circumference thereof like a brim to constitute a base of the second spring 42. Then, the inner circumferential end of the spring seat 32a contacts slidingly with the outer circumference of the cylindrical portion 44a of the second piston 44 in a hermetic manner, and the second piston 44 is arranged so as to slide axially on the second casing portion 32. [0053] The second pressure chamber 43 is constituted with spaces partitioned by the outer circumference of the cylindrical portion 44a of the second piston 44, the inner circumferences of the flange-like portion 44c and the second casing portion 32, and the spring seat 32. Then, the second casing portion 32 ig provided with a second pressurized fluid channel 45 communicated to the second pressure chamber 43, and compressed air (a pressurized fluid) is fed via the second pressurized fluid channel 45 into the second pressure chamber 43. In addition, a second feed/discharge port 45a, which is opened from the second pressurized fluid channel 45 to the outside of the cylinder main body 26 and through which compressed air is fed and discharged, is arranged so as to position below a swinging pin 16a (refer to Fig. 1 and Fig. 2) in a perpendicular direction. [0054] Further, the second spring 42 is installed as a coil spring arranged around the cylindrical portion 44a of the second piston 44 and arranged between the spring seat 32a and the flange-like portion 44b. As described above, the second spring 42 is placed so as to urge the flange-like portion 44b against the spring seat 32a (specifically, urging the second piston 44 against the cylinder main body 26) in the braking direction (direction indicated by the arrow A in the drawing) . Therefore, an urging force of the second spring 42 and the pressure from the second pressure chamber 43 act reversely on the second piston, and the spring brake means 29 changes from a state that compressed air is fed to the second pressure chamber 43 to a state that it is discharged, thereby the second piston 44 is moved in the braking direction by the urging force of the second spring 42. In addition, the spring brake means 29 is to urge the push rod 28 via the normal brake means 27 when movement of the second piston 44 in the braking direction occurs, as will be described later. [0055] The projected length adjusting means 30 is constituted with an outer cylinder member 47, a shaft rod 48, a guide member 49, the above-described uneven surface 40, an O-ring (elastic member) 50, a recess 51, a partition (regulating means) 52, and others. The projected length adjusting means 30 is installed as a mechanism for adjusting at braking operation a projected length of the push rod 28 from cylinder main body 26 at the time of releasing the brakes in a direction in which the first piston 36 moves. [0056] The outer cylinder member 47 is formed in a cylindrical shape, the base end of which is fixed to the first piston 36 via a flange plate 53 and a bolt 54, and constituted so as to move together with the first piston 36. A head flange 55 is accommodated into the base end of the outer cylinder member 47. A tapered narrowed portion 56 is formed on the inner circumferential surface at the axial end of the outer cylinder member 47 . The narrowed portion 56 can be used to press a radial outer edge of the head flange 55 to the leading end (the side in which the push rod 28 advances) . Further, a press pin 57 is installed on the outer cylinder member 4 7 so as to project inwardly, and the leading end of the press pin 57 can be used to press the head flange 55 to the base end (the side in which the push rod 28 retracts). [0057] Further, the outer cylinder member 47 is placed between a guide member 4 9 arranged around the push rod 28 and the second piston 44, inside which the guide member 4 9 is arranged. Then, the outer cylinder member 4 7 is provided with a stopper ring 58 attached to an outer circumference of the leading end thereof, and an inner circumferential portion at the leading end of the cylindrical member 44d of the second piston 44 is locked with the outer cylinder member 47 via the stopper ring 58. Thereby, when the spring brake means. 29 is actuated after a temporary actuation of the normal brake means 27, the second piston 44 is locked with the outer cylinder member 47 via the stopper ring 58 when movement of the second piston 4 4 to the braking direction occurs, thus urging the push rod 28 via the outer cylinder member 47 and the first piston 36 of the normal brake means 27. [0058] The shaft rod 48 is provided on the outer circumferential surface with a male thread 59 made threaded and mounted in a state of being screwed with a female thread 39 made threaded in the vicinity of the end of the first pressure chamber 35 on the inner circumferential surface of the push rod 28. The shaft rod 48 is screwed into the shaft hole of the push rod 28, by which the push rod 28 is attached to the shaft rod 48. Further, the. base end located on the first pressure chamber 35 in the shaft rod 48 is fixed to a head flange 55, and the shaft rod 48 is constituted so as to move together with the first piston 36. [0059] The guide member 4 9 is formed in a cylindrical shape and supported outside the shaft rod 48 so as to rotate freely via a thrust bearing (bearing) 60. Further, an urging spring 63 is laid between the guide member 4 9 and the head flange 55. Then, the guide member 49 is provided with a stepped shaft hole for inserting the push rod 28 thereinto, and an O-ring accommodating space 49a, which is a space for opening the uneven surface 40 and in which an O-ring 50 is arranged, is formed at a site of the shaft hole formed in a major diameter. In other words, the O-ring accommodating space 4 9a is formed at a site between the bottom of the major diameter (stepped portion) 4 9b on the guide member 4 9 and a stopper ring 61 fitted into the opening end of the major diameter, with the inner side (the side facing to the uneven surface 40 of the push rod 28) being opened. [0060] The O-ring 50 is arranged at the O-ring accommodating space 49 between the push rod 28 and the guide member 49. Then, aplurality (four) of O-rings 50 are arranged side by side axially at the O-ring accommodating space 49a, and a back-up ring 62 is arranged at both ends of each of the O-rings 50 (between adjacent O-rings 50) . Further, the bottom 49b and the stopper ring 61 are positioned in relation to the width of the O-ring 50 in such a manner that the O-ring 50 undergoes an elastic deformation as it is crushed to some extent between the bottom 49b of the major diameter on the guide member 49 and the stopper ring 61. Thereby, the O-ring 50 is deformed so as to expand to the inner circumference and engaged with the uneven surface 40 on the outer circumferential surface of the push rod 28, by which the guide member 49 is coupled with the push rod 28. As described above, the guide member 4 9 can move together with the push rod 28 and is attached to the push rod 28 in such a manner that a predetermined resisting force is applied when the push rod 28 makes a relative movement parallel with a direction in which the first piston 36 moves. Then, when a force exceeding a predetermined level is applied to the guide member 49, the 0-ring 50 is deformed to ride over a projection of the uneven surface 40, by which the push rod 28 is displaced with respect to the guide member 49. In addition, in the present embodiment, an 0-ring having a diameter of approximately 5 mm and a substantially circular cross section is used as the elastic member due to the fact that it is easily available and relatively high in dimensional accuracy. However, an elastic member mainly made with rubber or the like and having an oval or a rectangular cross section may be used. [0061] Fig. 7 shows the partition 52, the outer cylinder member 4 7 and the guide member 4 9 when viewed in a direction indicated by the arrow B to B in Fig. 6. The outer cylinder member 4 7 and the guide member 49 are illustrated in cross section. As shown in Fig. 6 and Fig. 7, the recess 51 is installed as a groove-like portion formed in a partially recessed manner on a circumference wall of the guide member 4 9 and extended short in circumferential and axial directions, and provided at a plurality (two) of sites on the guide member 49. [0062] Further, as shown in Fig. 6 and Fig. 7, the partition 52 is placed between the second piston 44 and the first spring 34, and installed in such a manner so as to separate a region where the normal brake means 27 is placed from that where the spring brake means 29 is placed inside the cylinder main body 26. Then, the partition 52 is provided with an engaging portion 64, which is engaged with the recess 51 installed on the guide member 49. The engaging portion 64 is engaged with the recess 51 in an axial direction of the guide member 49, thereby regulating a movable range (stroke) of the guide member 49 in a direction in which the first piston 36 moves. Further, the engaging portion 64 is engaged with the recess 51 in a circumferential direction of the guide member 49, thereby also regulating a movable range of the guide member 4 9 in a rotational direction in which a direction of moving the first piston 36 is given as a direction of the rotational shaft (to function as a detent) . In addition, the engaging portion 64 is provided at a plurality of sites (two) on the partition 52 so as to correspond to each of the recesses 51. Further, an opening is provided at a site corresponding to the recess 51 on the outer cylinder member 47, and the engaging portion 64 is engaged with the recess 51 through the opening. [0063] Still further, the partition 52 is provided at the center with an opening portion 65, through which the guide member 49 penetrates, and an engaging portion 64 is installed on the edge of the opening portion 65. The opening portion 65 is formed in such dimensions that a clearance covering all over the circumference is allowed to exist between an outer diameter of the guide member 49 (outer diameter perpendicular to an axial direction of the guide member 4 9) and the edge of the opening portion 65 so that the guide member 49 can penetrate through an opening portion 65 without engagement of the recess 51 with the engaging portion 64 at assembly of the brake cylinder device 2. As clearly shown in Fig. 7, in the brake cylinder device 2, the partition 52 and the guide member 4 9 are placed in such a manner that a radial center position of the guide member 49 can be made eccentric to that of the opening portion 65 of the partition 52 [0064] In addition, the spring brake means 29 is provided with a manual opening mechanism 66 for releasing manually a state that the brakes are in operation. The manual opening mechanism 66 is constituted with a fixing ring 67, a closing member 68, a fixing rod 69, a return spring 70 and an operation ring 71. Fig. 8 is a sectional view showing the manual opening mechanism 66 and a constituent arranged inside the fixing ring 67. In addition, the cross section indicated by the arrow C in Fig. 8 corresponds to the cross section given in Fig. 6. In Fig. 8, these constituents such as the fixing rod 69, the return spring 70 and the operation ring 71 are enlarged for illustration in larger dimensions than other constituents. [0065] As shown in Fig. 7 and Fig. 8, the fixing ring 67 is formed as a C-type slit-equipped ring, and head portions 67a, 67a having a wedge-shaped outer surface are formed on both ends opposing each other via the slit. The fixing ring 67 is set and arranged at the flange-like portion 44b of the second piston 44. Then, the fixing ring 67 is, as will be described later, urged by the closing member 68 and the fixing rod 69 to reduce in diameter, fitted into an annular groove 72 formed on the outer circumference of the cylindrical member 4 4d and engaged with the annular groove 72. With such a constitution, the fixing ring 67 is engaged with the annular groove 72, by which the cylindrical member 4 4d of the secondpiston 44 is fixedto another member of the secondpiston 44 and formed in an integrated manner. [0066] The closing member 68 is provided with an open U-shaped cross section and constituted as a member having two inclined surfaces in contact with wedge-shaped outer surfaces of the head portions 67a, 67a of the fixing ring 67 formed on the inside. The closing member 68 is guided along a predetermined groove at the second piston 44 and thereby placed so as to move to the fixing ring 67 in the radial direction. Further, the fixing rod 69 is constituted as a shaft-like stepped member having a wedge-shaped taper surface 69a at the leading end and placed so as to move back and forth on the second piston 44. Still further, the return spring 70 is installed as a coil spring placed around a minor diameter portion of the stepped fixing rod 69, and arranged between a stepped portion of the fixing rod. 69 and a spring washer 73. The return spring 70 is placed as described above, by which the fixing rod 69 is urged by the return spring 70, and the fixing rod 69 presses the closing member 68 toward the radial center of the fixing ring 67 in such a manner that the taper surface 69a on the leading end of the fixing rod 69 rides over outside the closing member 68. Therefore, the closing member 68 is pressed, by which the fixing ring 67 is kept reduced in diameter and the cylindrical member 44d at the second piston 44 is in a state of being integrated into the second piston 44. [0067] Further, the operation ring 71 is attached to the end opposite to the tapered surface 69 of the fixing rod 69. The operation ring 71 is pulled toward a direction in which it moves away from the spring washer 73 against an urging force of the return spring 70, thereby giving a gradual release to a pressed state of the closing member 68 by the fixing rod 69 so as to ride over the closing member 68 . In association with the release operation, the closing member 68 can move to the fixing ring 67 radially outwardly, while slidingly in contact with the tapered surface 69a of the fixing rod 69. Thereby, the fixing ring 67 is increased in diameter, and the closing member 68 is urged to the fixing ring 67 radially outwardly by the wedge-shaped outer surfaces of head portions 67a, 67a of the fixing ring 67 to release an engagement state of the fixing ring 67 with the annular groove 72 . At release of the engagement of the fixing ring 67 with the annular groove 72, a cylindrical member 44d coupled with other members is decoupled at the second piston 44 (an integrated state is released), a part excluding the cylindrical member 44d at the second piston 44 is allowed tomove independently of the cylindrical member 44d. Therefore, the operation ring 71 is pulled in a state that the spring brake means 29 is in operation, thus making it possible to develop a state that the urging force of the second spring 42 is not applied to the push rod 28 via the second piston 44. In other words, when the operation ring 71 is pulled, the push rod 28 is allowed to move in a direction in which the brakes are released together with the cylindrical member 4 4d locked by the stopper ring 58, the outer cylinder member 47, the shaft rod 48 and the first piston 36, even if the second piston 44 is urged by the second spring 42 toward a braking direction. It is, therefore, possible to release a state that the brakes are in operation. [0068] Still further, the brake cylinder device 2 is provided with a ventilation tube 72 communicating with the interior of the cylinder main body 26 with the exterior thereof. Fig. 9 shows only half the cross section of the brake cylinder device 2, which is divided at the center of the shaft. In addition, in Fig. 9, different cross sections are shown, which is divided by the dashed line D, a region indicated by the arrow Dl corresponds to the cross section given in Fig. 6 and a region indicated by the arrow D2 corresponds to a cross section different from that given in Fig. 6. Fig. 10 is an enlarged sectional view covering a ventilation tube 75 and the vicinity thereof. [0069] The ventilation tube 75 is formed as a rubber cylinder, which is a cylindrical elastic body with an elbow portion, and, as shown in Fig. 9 and Fig. 10, communicating with the outside via a ventilation portion 76 with a spring chamber 74 (a region surrounded by an inner circumferential wall of the second casing portion 32, a spring seat 32a, a flange-like portion 44b of the second piston 44 and a cylindrical portion 44a) in which the second spring 42 of the spring brake means 29 is placed. Then, as shown in Fig. 10, the ventilation tube 75 is provided with a thread portion 75a formed as a male thread on the outer circumference at one end thereof. The thread portion 75a is screwed with a female thread portion 77 formed at the second casing portion 32. In other words, the ventilation tube 75 is screwed and attached to the cylinder main body 26 at the thread portion 75a and communicated with the interior of the cylinder main body 26. [0070] Further, a filter 78 shown in Fig. 9 and Fig. 10 is attached inside the ventilation tube 75. Fig. 11 covers a front elevational view (Fig. 11 (a)) and a side elevational view (Fig. 11 (b)) showing only the filter 78. As shown in Fig. 11, the filter 7 8 is provided with a circular wire netting portion 7 8a and a frame portion 78b attached around the wire netting portion 78a. The wire netting portion 78a and the frame portion 78b are both formed as a steel-made rigid body. As shown in Fig. 9 and Fig. 10, the filter 78 is arranged at a position corresponding to a part which is inside a ventilation tube 75 and in which the thread portion 7 5a of the ventilation tube 75 is formed. [0071] Next, an explanation will be made for operations of the brake cylinder device 2. Fig. 6 shows a state that the brakes are not in operation, and neither the normal brake means 27 nor the spring brake means 29 is in operation. In a state that the brakes are not in operation as shown in Fig. 6, in order that the spring brake means 29 is not in operation, compressed air is fed from the second feed/discharge port 4 5 to the second pressure chamber 43, thereby the second piston 44 is kept urged against an urging force of the second spring 42 in an anti-braking direction, which is reverse in a direction indicated by the arrow A in the drawing (a direction reverse to the braking direction in which the brakes are released). [0072] When apredetermined valve (not illustrated) is controlled to feed compressed air to the first feed/discharge port 37a in a state that the brakes are not in operation as shown in Fig. 6, the first piston 36 is pressed toward a braking direction (a direction indicated by the arrow A in Fig. 6) against the first spring 34, and the outer cylinder member 47 fixed to the first piston 36 is also moved in the braking direction. Then, the narrowed portion 5 6 formed on the inner circumferential surface at the base end of the outer cylinder member 47 presses the outer edge of the head flange 55, by which the head flange 55 is also moved in the braking direction and the push rod 28 coupled with the shaft rod 48 is also moved in the direction given by the arrow A. In addition, at this time, the head flange 55 and the shaft rod 48, will not rotate but are simply pushed by the outer cylinder member 47. Therefore, the normal brake means 27 is actuated and the push rod 28 is pushed to advance in the braking direction (together with the outer cylinder member 47 and the guide member 49) , thereby actuating the brake caliper device 1. [0073] As described above, where a braking force of the normal brake means 27 is applied to change a vehicle from a halt state to a parking state as it is, a predetermined valve (not illustrated) is controlled, with the above-described normal brake means 27 being in operation, and compressed air sealed at the second pressure chamber 43 is discharged from the second feed/discharge port 45a. Thereby, the second pressure chamber 43, which acts against the urging force of the second spring 42, is released and the second piston 44 is extended by the urging force of the second spring 42, thereby the cylindrical member 4 4d of the second piston 4 4 is brought into contact with a stopper ring 58 to keep a state that the second piston 44 is locked with the outer cylinder member 47. In this state, even when the normal brake means 27 is released or compressed air fed to the first pressure chamber 35 is discharged and the first piston 36 is moved by the first spring 34 in an anti-braking direction, the push rod 28 is urged by the spring brake means 29 to keep a state that the braking force is applied. In addition, when the spring brake means 2 9 is released manually, as described previously, an operation ring 71 of the manual opening mechanism 66 is used to release the cylindrical member 44d fixed to the second piston 44. [0074] In a state that only the normal brake means 27 is actuated to develop a braking force, with the spring brake means 2 9 kept non-operating, a predetermined valve (not illustrated) is controlled to discharge compressed air, which has been fed to the first pressure chamber 35, through the first feed/discharge port 37a, thereby the first piston 36 is pushed by the first spring 34 in an anti-braking direction, and the outer cylinder member 47 is also pulled in the anti-braking direction. As a result, the head flange 55 is pressed, by a press pin 57, and the shaft rod 48 and the push rod 28 coupled with the shaft rod 4 8 are also pulled in the anti-braking direction and retracted. Therefore, a state that the brakes are not in operation is returned, as shown in Fig. 6. [0075] On the other hand, when a braking surface of the brake pad 14 shows wear, a stroke of the push rod 28 is increased which is necessary for actuating the brakes to result in a greater stroke of the guide member 49 connected to the push rod 28 via an O-ring 50. When the stroke exceeds a stroke regulated by a recess 51 installed on the guide member 49 and an engaging portion 64 of the partition 52, the engaging portion 64 is engaged with the recess 51, thus giving a great returning force to the guide member 49. Therefore, after the engaging portion 64 is engaged with the recess 51, the O-ring 50 is deformed to ride over a projection of the uneven surface 40, by which the push rod 28 is deviated (displaced) to the guide member 49 only by a portion corresponding to a further stroke of the push rod 28. In other words, the first piston 36 is moved toward a projected direction (a braking direction), by which the engaging portion 64 is engaged with the recess 51, and the first piston 3 6 is further moved toward the projected direction, thereby the shaft rod 48, the push rod 28 and others are displaced toward the projected direction, with only the guide member 49 remaining as it is. In addition, in most cases, since a wear quantity of the brake pad for each braking operation is quite small, a displacement quantity of the push rod 28 for one time is accordingly small to such an extent of a clearance between projections on the uneven surface 40. [0076] Further, where compressed air is discharged from the first feed/discharge port 37a to release the brakes by the normal brake means 27 after a relative displacement takes place between the push rod 28 and the guide member 4 9, the first piston 36 is returned by the first spring 34 toward an anti-braking direction, and the head flange 55 is pushed toward the anti-braking direction by the press pin 57 attached to the outer cylinder member 47, which is pulled thereby. Then, the head flange 55 is rotated together With the shaft rod 48 rotationally supported by a thrust bearing 60, the shaft rod 48 is taken out from the push rod 28, and a displacement of the push rod 28 with respect to the guide member 4 9 in an advancing direction is absorbed by a screw movement. As a result, the push rod 28 is to project in the advancing direction only by an extent of the above deviation. Therefore, the push rod 28 is adjusted for the projected length and the brake cylinder device 2 can be subsequently actuated by a normal stroke of the push rod 28. [0077] As described above, the brake cylinder device 2 of the present embodiment is constituted in such a manner that the push rod 28 moving together with the first piston 36 of the normal brake means 27 penetrates through the second piston 44 of the spring brake means 2 9 and a predetermined resisting force is applied between the guide member 4 9 of the projected length adjusting means 30 and the push rod 28. Therefore, the brake cylinder device 2, which is provided with the normal brake means 27, the spring brake means 29 and the projected length adjusting means 30, can be made compact by preventing the device from being complicated in mechanism and enlarged. Then, the pro j ected length adj ustingmeans 30 is provided with a regulating means 52 placed between the second piston 4 4 and the first spring 34, having an engaging portion 64 engaged with a recess 51 formed on the guide member 4 9 and simply constituted so as to regulate a movable range of the guide member. It is, therefore, possible to regulate a range where the push rod 28 is adjusted for the projected length and a range where it is not adjusted by.using a simple mechanism. [0078] Thus, according to the brake cylinder device 2, it is possible to provide such a constitution that is provided with a normal brake means 27, a spring brake means 2 9 and means 30 for adjusting the projected length of the push rod 28, capable of preventing the device from being complicated in mechanism and enlarged and also capable of realizing means for regulating a range where the projected length of the push rod 28 is adjusted and a range where it is not adjusted by using a simple mechanism. [0079] Further, according to the brake cylinder device 2, a recess 51 and a regulating means 52 having an engaging portion 64 to be engaged with the recess 51 are used to function also as a detent for the guide member 49. It is, therefore, possible to realize not only the function of regulating a movable range in a direction in which the first piston 36 of the guide member 4 9 moves but also the function as a detent by using the single regulating means 52, thus making the mechanism simple. [0080] Further, according to the brake cylinder device 2, a plurality of pairs of the corresponding recesses 51 and the engaging portions 64 are installed, by which loads acting on engaging parts can be dispersed to reduce wear, which occurs at the recesses 51 and the engaging portions 64, thereby improving the durability. [0081] Further, according to the brake cylinder device 2, the regulating means 52 is installed as a partition 52 for separating a region of the normal brake means 27 from that of the spring brake means 29, thus making it possible to form the regulating means 52 in a thin flat-plate shape and also make the constitution simple. Thus, the simply constituted regulating means 52 can be placed so as to attain an effective use of space in the brake cylinder device 2. Then, at assembly of the brake cylinder device 2, a guide member 4 9 can penetrate through an opening portion 65 of the partition 52 via a predetermined clearance without engagement of the recess 51 with the engaging portion 64 . Therefore, the assembly can be carried out easily and with an increased efficiency. [0082] Further, according to the brake cylinder device 2, it is possible to provide easily and simply such a constitution that the guide member 4 9 can penetrate through the opening portion 65 of the partition 52 via a predetermined clearance without engagement of the recess 51 with the engaging portion 64 at assembly of the brake cylinder device 2 by making the center of the guide member 49 eccentric to the center of the opening portion 65. [0083] Further, according to the brake cylinder device 2, the projected length adjusting means 30 is constituted in such a manner that the elastic member 50 is deformed and engaged (cut into), thus making it possible to stabilize a frictional force or a binding force between the push rod 28 and the guide member 49. Thereby, it is possible to adjust and control a sliding resistance on the projected length adjusting means 30 in a simple constitution. [0084] Further, according to the brake cylinder device 2, since the push rod 28 is attached by being screwed with the shaft rod 48 moving together with the first piston 36, it is possible to provide such a constitution that a projected length of the push rod 28 is absorbed by a screw movement made by the shaft rod 48 with respect to the push rod 28. Therefore, it is possible to provide such a constitution that prevents a positional deviation of the first piston 36 with respect to a cylinder main body 26 also in a state that the projected length of the push rod 28 is adjusted, thereby keeping a capacity of the first pressure chamber 35 substantially at a constant level. [0085] Further, according to the brake cylinder device 2, the second piston 44 is locked with the outer cylinder member 47, which is arranged between the guide member 4 9 and the second piston 44 to move together with the first piston 36, thus making it possible to urge the push rod 28. Therefore, the outer cylinder member 47 constituted in a simplified shape is placed, thus providing in a simple mechanism such a constitution that the push rod 28 is urged via the normal brake means when movement of the second piston 44 in the braking direction occurs. [0086] Further, according to the brake caliper device 1 of the present embodiment, it is possible to provide the brake caliper device 1, which is provided with the brake cylinder device 2 having the normal brake means 27, the spring brake means 29 and the means 30 for adjusting the projected length of the push rod 28, preventing the device f rombeing complicated inmechanism and enlarged, and making it possible to realize means 52 for regulating a range where the projected length of the push rod 28 is adjusted and a range where it is not adjusted by using a simple mechanism. [0087] Further, according to the brake caliper device 1, since the first feed/discharge port 37a and the second feed/discharge port 45a are positioned below the swinging pin 16a in a perpendicular direction, it is possible to prevent the caliper body 11 and the brake cylinder device 2 from generating a momentum in a swinging direction both when feeding a pressurized fluid via the first feed/discharge port 37a to the first pressure chamber 35 and when feeding the pressurized fluid via the second feed/discharge port 45a to the second pressure chamber 43. Therefore, it is possible to prevent a localized contact of the brake pad 14 on the brake disc 15 and also a localized wear of the brake pad 14 in an emergency of the pressurized fluid. [0088] Further, according to the brake caliper device ,1, it is possible to attach the filter 78 together with the ventilation tube 75 only by screwing the ventilation tube 75 having the filter 78 into the cylinder main body 26 at the thread portion 75a at the end thereof. Then, the filter 78 is placed inside the ventilation tube 75, thereby eliminating the necessity for providing a member or the like especially intended for attaching the filter 78. Therefore, it is possible to easily and quickly attach the filter 78 and the ventilation tube 75 to the cylinder main body 26 and also perform work for attaching the filter in a simplified manner. [0089] Further, according to the brake caliper device 1, the leg 18 is appropriately set for the dimensions when the brake caliper device 1 is removed and arranged on a floor for maintenance work of the brake caliper device 1, thus making it possible to keep the brake caliper device 1 horizontal on the basis of the lower end on one end of the caliper body 11 and the leg 18. It is, therefore, possible to easily perform the maintenance work or the like, thereby improving work efficiency. [0090] Further, according to the brake caliper device 1, such a structure can be provided that the brake pad 14 can be easily attached or detached by using a latch 19 urged by a flat spring 22 in a direction different from that in which the brake pad 14 is attached or detached. Then, it is, possible to prevent the latch 19 from being unlocked only by inserting a snap pin 20 below a back plate 12. In other words, in performing work for exchanging the brake pad 14, the snap pin 20 is removed, thereby allowing the latch 19 to be unlocked, the latch 19 is turned against the flat spring 22, with a possible drop of the brake pad 14 taken into account, thus making it possible to securely remove the brake pad 14. Then, even at attachment of a new brake pad 14, the latch 19 is locked by the flat spring 22 at a stage where the key portion 14a of the brake pad 14 is allowed to slide on the key groove 12b of the back plate 12 and arrives at a predetermined position. Therefore, the new brake pad can be easily attached. Further, the latch 19 is coupled with the snap pin 20 by using a coupling chain 21, thereby easily providing a constitution for preventing the removal or loss of the snap pin 20. As a result, a brake caliper device 1 is provided, which is free of an inadvertent drop of the brake pad 14, realizing work of easily exchanging the brake pad so that the support only by the brake pad 14 can be released at any time, and also eliminating the necessity for troublesome and skilled work in tightening bolts by using a bundling wire in attaching the brake pad 14. [0091] An explanation has been so far made for embodiments of the present invention. However, the present invention shall not be limited to the above embodiments but may be executed in various modifications without departing from the claims of the patent. For example, the present invention may be executed in the following modifications. [0092] An explanation has been made for the present embodiment by exemplifying an air cylinder device actuated by air pressure used in the brake cylinder device 2 as a driving source of the brake caliper device 1. There is no restriction on the driving source and may include a cylinder device actuated by hydraulic pressure or others. [0093] Further, there is no restriction on a constitution in which the uneven surface 40 is formed on an outer circumferential surface of the push rod 28 and may include a constitution in which the outer circumferential surface is made flat and a predetermined resisting force is given from a frictional force imparted to the push rod 28 from an elastic member such as the O-ring 50. In this case, the push rod 28 can be easily machined on the outer circumferential surface, thus resulting in reduction in machining costs. Still further, there is no restriction in a case where recesses and projections are repeatedly arranged on the surface of the push rod 28 in a direction in which the push rod 2 8 moves to form the uneven surface 40, and also included is a case where surface treatment such as blast is given to the surface, thus making it possible to adjust a frictional force. [0094] Further, there is no restriction in a case where the push rod 2 8 is coupled with the guide member 4 9 via an elastic.member. Also included is a case where the push rod is coupled with the guide member by a mechanical constitution in such a manner that a predetermined resisting force can be applied at movement of the push rod to the guide member in parallel in a direction in which the first piston moves, for example, a gear mechanism having a predetermined rotational resistance is actuated, thereby the push rod is moved to the guide member. [0095] Still further, an explanation has been made for the brake cylinder device 2 of the present embodiment by referring to a case where it is used in a disc brake-type brake caliper device 1. The present invention shall not be restricted thereto. In other words, the brake cylinder device 2 is not restricted to a case where it is used in a disc brake-type brake mechanism but may be used in a disc brake-type brake mechanism in which a brake pad is attached to the leading end of a push rod and the brake pad is allowed to be in contact with the wheel tread, thereby generating a braking force. [0096] In addition, in the present embodiment, an explanation has been made for the projected length adjusting means 30, which is constituted with the recess 51 installed on the guide member 49 and the regulating means 52 having the engaging portion 64 to be engaged with the recess 51. Also included is a projected length adjusting means which is provided not with the recess 51 but with a projection, that is, that constituted with a projection installed on the guide member 4 9 and a regulating means having an engaging portion to be engaged with the projection. [Claim 1] A brake cylinder device, which is used in a brake mechanism for vehicles, comprising: a normal brake means having a first piston in which an urging force of a first spring acts reversely on the pressure from a first pressure chamber, wherein a pressurized fluid is fed to the first pressure chamber, thereby the first piston moves relatively with respect to the cylinder main body against the urging force of the first spring and moves in a braking direction; a push rod, which is movable together with the first piston; a projected length adjusting means having a guide member, which is movable together with the push rod and attached to the push rod in such a manner that a predetermined resisting force is applied when the push rod makes a relative movement parallel with a direction in which the first piston moves, wherein adjusted is a projected length of the push rod from the cylinder main body at release of the brakes in a direction in which the first piston moves; a spring brake means having a second piston in which an urging force of the second spring acts reversely on the pressure from the second pressure chamber and the push rod penetrates therethrough, wherein a state of feeding a pressurized fluid to the second pressure chamber is shifted to a state of discharging it, thereby the second piston is moved in the braking direction by the urging force of the second spring and also the push rod is urged through the normal brake means; wherein the projected length adjusting means is provided with a recess or a projection installed on the guide member and also a regulating means having an engaging portion to be engaged with the recess or the projection and placed between the second piston and the first spring, thus regulating a movable range of the guide member in a direction in which the first piston moves. [Claim 2] The brake cylinder device as set forth in claim 1, wherein the regulating means also regulates a movable range of the guide member in the rotating direction around the central axis of the first piston by engagement of the engaging portion with the recess or the projection. [Claim 3] The brake cylinder device as set forth in claim 1 or claim 2, wherein the recess or the projection is installed at a plurality of places on the guide member and the engaging portion is installed at a plurality of places on the regulating means corresponding individually to each of the recesses or the projections. [Claim 4] The brake cylinder device as set forth in any one of claims 1 to 3, wherein the regulating means is installed as a partition for separating a region where the normal brake means is placed from a region where the spring brake means is placed inside the cylinder main body, an opening portion through which the guide member penetrates is formed at the center of the partition, the engaging portion is installed at an edge, which forms the opening portion, the opening portion is formed in such dimensions that allows a clearance covering the entire circumference to exist between an outer diameter of the guide member and an edge of the opening portion so that the guide member can penetrate through the opening portion without making an engagement of the recess or the projection with the engaging portion at assembly of the brake cylinder device. [Claim 5] The brake cylinder device as set forth in claim 4, wherein the partition and the guide member are placed in such a manner that a radial center position of the guide member is made eccentric to that of the opening portion. [Claim 6] The brake cylinder device as set forth in any one of claims 1 to 5, wherein the projected length adjusting means is additionally provided with uneven surface formed by repeatedly arranging recesses and projections on an outer surface of the push rod in a direction in which the push rod moves and an elastic member placed between the push rod and the guide member, the elastic member is deformed to make an engagement with the uneven surface, by which the guide member is connected with the push rod, when a force greater than a predetermined value is applied to the guide member, the elastic member is deformed to ride over a projection of the uneven surface, thereby the push rod is displaced with respect to the guide member. [Claim 7] The brake cylinder device as set forth in any one of claims 1 to 6, wherein the projected length adjusting means is additionally provided with a shaft rod, which moves together with the first piston and to which the push rod is attached, the push rod is formed in a cylindrical shape having a shaft hole extending parallel with a direction in which the first piston moves and a female thread is made at least at a part of the inner surface of the shaft hole, and a male thread to be screwed with the female thread is made at least at a part of the outer surf ace of the shaft rod, which is screwed into the shaft hole. [Claim 8] The brake cylinder device as set forth in any one of claims 1 to 7, wherein the projected length adjusting means is placed between the guide member arranged around the push rod and the second piston and additionally provided with an outer cylinder member in which the guide member is arranged therein to move together with the first piston, and the second piston is locked with the outer cylinder member when movement of the second piston in the braking direction occurs, by which the spring brake means urges the push rod via the outer cylinder member and the first piston of the normal brake means. [Claim 9] A brake caliper device, comprising the brake cylinder device as set forth in any one of claims 1 to 8 and a caliper body having the brake cylinder device and attached so as to make a relative movement in a shaft direction with respect to truck wheels, and the brake cylinder device is actuated, by which a disc on the shaft is held between a pair of brake shoes attached to the caliper body, thus generating a braking force. The brake cylinder device of the present invention is provided with a normal brake means, a spring brake means, a push rod, and a projected length adjusting means having a guide member, which is movable together with the push rod and attached to the push rod in such a manner that a predetermined resisting force is applied at movement of the push rod, thereby adjusting a projected length from a cylinder main body of the push rod. The projected length adjusting means is additionally provided with a recess installed on a guide member and a regulating means having an engaging portion to be engaged with the recess and placed between the second piston and the first spring to regulate a movable range in a direction in which the first piston of the guide member moves.

Full Text

BRAKE CYLINDER DEVICE AND BRAKE CALIPER DEVICE
CROSS REFERENCE TO RELATED APPLICATION
[0001]
The present invention is an application for claiming the
right of priority on the basis of the Japanese Patent Application
No. 2007-104970 (filed on April 12, 2007).
BACKGROUND OF THE INVENTION
1 Field of the Invention
[0002]
The present invention relates to a brake cylinder device
provided with a push rod for actuating a brake mechanism for
vehicles and capable of automatically adjusting the projected
length of the push rod from a cylinder main body at braking
operation, and a brake caliper device provided with the brake
cylinder device.
2 Description of Related Art
[0003]
As for a brake cylinder device capable of automatically
adjusting the projected length of a push rod from a cylinder
main body, Patent Document 1 (Japanese Published Examined Patent

Application No. H6-67725 (claim 1, Fig. 2), has disclosed a
constitution, which is provided with an output piston having
inside a cylinder a push rod connected to a brake shoe for braking
a wheel tread and a friction ring assembly made so as to increase
a friction/sliding resistance.to the inner surface of a cylinder
by holding one elastic ring between two circular plates to expand
radially and outwardly. Patent Document 1 has described that
when the brake shoe wears while the brakes are in operation,
an output piston and a friction ring assembly move according
to an amount of water, whereas the friction ring assembly will
not move due to a greater sliding resistance when the brakes
are loosened, as a result, there is secured a proper clearance
between the brake shoe and the wheel tread. Then, Patent
Document 1 has also described a constitution in which a nut
is used to attach a stepped shaft to the center of the friction
ring assembly, an end plate is fixed on one end surface of the
output piston by using fitting screws, and a release spring
is placed between a. flange formed at one end of the stepped
shaft and the end plate. It has also described that a relative
momentum between the output piston and the friction ring assembly
is restricted so as not to exceed a predetermined clearance.
[0004]
Further, as a brake mechanism for railway vehicles, Patent

Document 2 (Japanese Published Unexamined Patent Application
No. S63-125834) has disclosed a constitution of a brake cylinder
device having both a normal brake means used in a normal operation
and actuated by pressure air as well as a spring brake means
used in a prolonged parking and actuated by spring force even
in the absence of pressure air.
[0005]
Regarding a brake cylinder device having both the normal
brake means and the spring brake means such as that disclosed
in Patent Document 2, such an idea has been proposed that, as
shown as disclosed in Patent Document 1, there is provided a
projected length adjusting means capable of adjusting
automatically the projected length of a push rod from a cylinder
main body when the brakes are in operation, thereby improving
the convenience as a brake cylinder device.
[0006]
However, Patent Document 1 has disclosed only an
embodiment having a friction ring assembly as the
above-described projected length adjust ing means and disclosed
only a special constitution having a stepped shaft or the like
corresponding to a projected length adjusting means by using
a friction ring assembly as means for regulating a relative
momentum between a push rod-equipped output piston and the

friction ring assembly. Therefore, if the projected length
adjusting means disclosed in Patent Document 1 is incorporated
into a brake cylinder device having both a normal brake means
and a spring brake means, the brake cylinder device is
complicated in mechanism and enlarged. As such, a brake
cylinder device having a normal brake means and a spring brake
means has a difficulty in realizing means for regulating a range
where the projected length of a push rod is adjusted and a range
where it is not adjusted in the projected length adjusting means
by using the special constitution disclosed in Patent Document
1.
SUMMARY OF THE INVENTION
[0007]
The present invention has been made in view of the
above-described situation, an object of which is to provide
a brake cylinder device having a normal brake means, a spring
brake means and means for adjusting the projected length of
a push rod, capable of preventing the device from being
complicated in mechanism or increased in size and also capable
of realizing means for regulating a range where the projected
length of the push rod is adjusted and a range where it is not
adjusted by using a simple mechanism as well as a brake caliper

device equipped with the brake cylinder device.
[0008]
The brake cylinder device according to the first invention
for attaining the above object is a brake cylinder device used
in a brake mechanism for vehicles, which is provided with a
normal brake means having a first piston in which an urging
force of a first spring acts reversely on the pressure from
a first pressure chamber, wherein a pressurized fluid is fed
to the first pressure chamber, thereby the.first piston moves
relatively with respect to the cylinder main body against the
urging force of the first spring andmoves in a braking direction,
a push rod, which is movable together with the first piston,
projected length adjusting means having a guide member, which
is movable together with the push rod and attached to the push
rod in such a manner that a predetermined resisting force is
applied when the push rod makes a relative movement parallel
with a direction in which the first piston moves, wherein
adjusted is a projected length of the push rod from the cylinder
main body at release of the brakes in a direction in which the
first piston moves, and a spring brake means having a second
piston in which an urging force of the second spring acts
reversely on the pressure from the second pressure chamber and
the push rod penetrates therethrough, wherein a state of feeding

a pressurized fluid to the second pressure chamber is shifted
to a state of discharging it, thereby the second piston is moved
in the braking direction by the urging force of the second spring
and the push rod is also urged via the normal brake means,
wherein the projected length adjusting means is provided with
a recess or a projection installed on the guide member and also
a regulating means having an engaging portion to be engaged
with the recess or the projection and placed between the second
piston and the first spring, thus regulating a movable range
of the guide member in a direction in which the first piston
moves.
[0009]
According to the present invention, such a constitution
is provided that the push rod, which moves together with the
first piston of the normal brake means, penetrates through the
second piston of the spring brake means and a predetermined
resisting force acts between the push rod and the guide member
of the projected length adjusting means. Therefore, a brake
cylinder device having the normal brake means, the spring brake
means and the projected length adjusting means can be made
compact by preventing the device from being complicated in
mechanism and enlarged. Then, the projected length adjusting
means is provided with a simply-structured regulating means,

which is placed between the second piston and the first spring
and equipped with an engaging portion making an engagement with
a recess or a projection installed on the guide member, thereby
regulating a movable range of the guide member. Therefore,
it is possible to regulate a range where the projected length
of the push rod is adjusted and a range where it is not adjusted
by using a simple structure.
As a result, the present invention can provide a brake
cylinder device having a normal brake means, a spring brake
means and an adjusting means for the projected length of the
push rod, which can prevent the device from being complicated
in mechanism and enlarged and also realize means for regulating
a range where the projected length of the push rod is adjusted
and a range where it is not adjusted by using a simple
constitution.
[0010]
The brake cylinder device according to the second
invention is the brake cylinder device according to the first
invention, in which the regulatingmeans also regulates amovable
range of the guide member in the rotating direction around the
central axis of the first piston by engagement of the engaging
portion with the recess or the projection.
[0011]

According to the above constitution, the recess or the
projection and the regulating means having an engaging portion
to be engaged with the recess or the projection are used to
function as a detent for the guide member as well. It is,
therefore, possible to realize not only the function of
regulating a movable range in a direction in which the first
piston of the guide member moves but also the function as a
detent by using one regulating means, thus making the brake
cylinder device simple in mechanism.
[0012]
The brake cylinder device according to the third invention
is the brake cylinder device according to the first invention
or the second invention, wherein the recess or the projection
is installed at a plurality of places on the guide member, and
the engaging portion is also installed at a plurality of places
on the regulating means corresponding individually to each of
the recesses or the projections.
[0013]
According to the present invention, a plurality of the
corresponding recesses or projections and the engaging portions
are installed, by which loads acting on mutually engaging parts
can be dispersed to reduce wear, which occurs at the recesses
or projections and the engaging portions . Therefore, the brake

cylinder device is improved in durability.
[0014]
The brake cylinder device according to the fourth
invention is the brake cylinder device according to any one
of the first invention to the third invention, wherein the
regulating means is installed as a partition for separating
a region where the.normal brake means is placed from a region
where the spring brake means is placed inside the cylinder main
body, an opening portion through which the guide member
penetrates is formed at the center of the partition, the engaging
portion is installed at an edge forming the opening portion,
the opening portion is formed in such dimensions that allows
a clearance covering the entire circumference to exist between
an outer diameter of the guide member and an edge of the opening
portion so that the guide member can penetrate through the
opening portion without making an engagement of the recess or
the projection with the engaging portion at assembly of the
brake cylinder device.
[0015]
According to the present, invention, the regulating means
is installed as a partition for separating a region of the normal
brake means from that of the spring brake means, thus making
it possible to form the regulating means in a thin flat-plate

shape and also simplify the constitution. Thus, the simply
constituted regulating means can be placed so as to attain an
effective use of space in a brake cylinder device. Then, at
assembly of the brake cylinder device, a guide member can
penetrate through an opening portion of the partition via a
predetermined clearance without engagement of the recess or
the projection with the engaging portion. Therefore, the
assembly can be conducted easily and with an increased
efficiency.
[0016]
The brake cylinder device according to the fifth invention
is the brake cylinder device according to any one of the first
invention to the fourth invention, wherein the partition and
the guide member are placed in such a manner that a radial center
position of the guide member is eccentric to that of the opening
portion.
[0017]
According to the present invention, the center of the
guide member is made eccentric to the center of the opening
portion, thus making it possible to provide In a simple manner
such a constitution that a guide member can penetrate through
an opening portion of the partition via a predetermined clearance
without engagement of the recess or the projection with the

engaging portion at assembly of the brake cylinder device.
[0018]
The brake cylinder device according to the sixth invention
is the brake cylinder device according to any one of the first
invention to the fifth invention, wherein the projected length
adj ust ing means is additionally provided with an uneven surface
formed by repeatedly arranging recesses and projections on an
outer surface of the push rod in a direction in which the push
rod moves and an elastic member placed between the push rod
and the guide member, the elastic member is deformed and engaged
with the uneven surface, by which the guide member is connected
with the push rod, and when a force greater than a predetermined
value is applied to the guide member, the elastic member is
deformed to ride over a proj ection of the uneven surf ace, thereby
the push rod is displaced with respect to the guide member.
[0019]
Conventionally, according to the constitution described
in Patent Document 1, for example, only a frictional force
between the inner circumferential surface of a flat cylinder
and the surface of an elastic ring is used to generate a sliding
resistance, thereby the sliding resistance of the friction ring
assembly is easily made unstable by the surface condition and
wear of the inner circumferential surface of the cylinder or

the wear of the surf ace of the elastic ring. Further, adjustment
is made by using a adjusting screw, which may complicate the
adjustment and control of the sliding resistance.
However, according to the present invention, the elastic
member is deformed and engaged (cut into), thus making it
possible to stabilize a frictional force or a binding force
between the push rod and the guide member. Thereby, it is
possible to adjust and control the sliding resistance by a simple
constitution.
[0020]
The brake cylinder device according to the seventh
invention is the brake cylinder device according to any one
of the first invention to the sixth invention, wherein the
projected length adjusting means is additionally provided with
a shaft rod, which moves together with the first piston and
to which the push rod is attached, the push rod is formed in
a cylindrical shape having a shaft hole extending parallel with
a direction in which the first piston moves, a female thread
is made at least at a part of the. inner surface of the shaft
hole, and a male thread to be screwed with the female thread
is made at least at a part of the outer surface of the shaft
rod, which is screwed into the shaft hole.
[0021]

According to the present invention, since the push rod
is attached by being screwed With the shaft rod moving together
with the first piston, it is possible to provide such a
constitution that a projected length portion of the push rod
is absorbed by a screw movement made by the shaft rod with respect
to the push rod. Therefore, it is possible to provide such
constitutions so as to prevent a positional deviation of the
first piston with respect to a cylinder main body also in a
state that the projected length of the push rod is adjusted,
thereby retaining the capacity of the first pressure chamber
substantially at a constant level.
[0022]
The brake cylinder device according to the eighth
invention is the brake cylinder device according to any one
of the first invention to the seventh invention, wherein the
projected length adjusting means is placed between the guide
member arranged around the push rod and the second piston,
additionally provided with an outer cylinder member internally
having the guide member and moving together with the first piston,
and the second piston is locked with the outer cylinder member
when movement of the second piston in the braking direction
occurs, by which the spring brake means urges the push rod via
the outer cylinder member and the first piston of the normal

brake means.
[0023]
According to the present invention, the second piston
is locked with an outer cylinder member, which is arranged
between the guide member and the second piston to move together
with the first piston, thus making it possible to urge the push
rod. Therefore, the outer cylinder member constituted in a
simple shape is placed, thereby providing in a simple mechanism
such a constitution that the push rod is urged via the normal
brake means when movement of the second piston in the braking
direction occurs.
[0024]
Further, as another view of the invention, it is possible
to constitute an invention of a brake caliper device having
any one of the above-described brake cylinder devices. In other
words, the brake caliper device according to the ninth invention
is provided with the brake cylinder device according to any
one of the first invention to the eighth invention and a caliper
body having the brake cylinder device and attached so as to
make a relative movement in a shaft direction with respect to
truck wheels, and the brake cylinder device is actuated, by
which a disc on the shaft is held between a pair of brake shoes
attached to the caliper body, thus generating a braking force.

[0025]
According to the present invention, it is possible to
provide a brake caliper device, which is provided with a brake
cylinder device having a normal brake means, a spring brake
means and means for adjusting the projected length of a push
rod, preventing the device from being complicated in mechanism
and enlarged, and making it possible to realize means for
regulating a range where the projected length of the push rod
is adjusted and a range where it is not adjusted by using a
simple mechanism.
[0026]
The brake caliper device according to the tenth invention
is the brake caliper device of the ninth invention, wherein
the caliper body is attached to the truck via a swinging pin
so as to swing axially or parallel with a direction in which
a vehicle advances, the brake cylinder device installed on the
brake caliper device is provided on the cylinder main body with
a first pressurized fluid channel communicated to the first
pressure chamber and a second pressurized fluid channel
communicated to the second pressure chamber, a first
feed/discharge port opened from the first pressurized fluid
channel to the outside of the cylinder main body for feeding
and discharging a pressurized fluid and a second feed/discharge

port opened from the second pressurized fluid channel to the
outside of the cylinder main body for feeding and discharging
the pressurized fluid are respectively placed so as to be
positioned in a perpendicular direction with respect to the
swinging pin.
[0027]
According to the present invention, since the first
feed/discharge port and the second feed/discharge port are
positioned below the swinging pin in a perpendicular direction,
it is possible to prevent the caliper body and the brake cylinder
device from having a momentum in a swinging direction both when
feeding a pressurized fluid via the first feed/discharge port
to the first pressure chamber and when feeding the pressurized
fluid via the second feed/discharge port to the second pressure
chamber. Therefore, it is possible to prevent a localized
contact of a brake shoe on a disc and also a localized wear
of the brake shoe in an emergency of the pressurized fluid.
[0028]
The brake caliper device according to the eleventh
invention is the brake caliper device of the ninth invention,
wherein the brake cylinder device installed on the brake caliper
device is provided with a ventilation tube formed as a
cylindrical elastic body and attached to the cylinder main body

by being screwed with a thread portion installed on the outer,
circumference of one end thereof, thereby communicating with
the interior of the cylinder main body, and a filter made of
a rigid body and arranged at a position, which is inside the
ventilation tube and corresponding to a part where the thread
portion is formed on the ventilation tube.
[0029]
According to the present invention, it is possible to
attach the filter together with the ventilation tube only by
screwing the ventilation tube on which the filter is installed
into the cylinder main body at the thread portion 75a at the
end thereof. Then, the filter is placed inside the ventilation
tube, thereby eliminating the necessity for providing a member
or the like especially intended for attaching the filter.
Therefore, it is possible to attach the filter and the
ventilation tube to the cylinder main body easily and quickly
and also perform work for attaching the filter in a simplified
manner.
[0030]
. The brake caliper device according to the twelfth
invention is the brake caliper device of the ninth invention,
wherein the caliper body is provided with a pair of brake levers,
one end of which is actuated by the brake cylinder device

installed on the brake caliper device, and also provided with
a pair of brake-shoe retaining portions respectively attached
to the other end of the pair of brake levers to retain the brake
shoe and a leg projected on the lower end of the brake-shoe
retaining portion.
[0031]
According to the present invention, the leg is
appropriately set for the dimensions when the brake caliper
device is removed and arranged on a floor or the like for
maintenance work of the brake caliper device, thus making it
possible to keep the brake caliper device horizontal on the
basis of the lower end on one end of the caliper body and the
leg. It is, therefore, possible to easily perform the
maintenance work or the like, thereby improving the work
efficiency.
[0032]
The brake caliper device according to the thirteenth
invention is the brake caliper device of the ninth invention,
wherein the caliper body is provided with a pair of brake levers,
one end of which is actuated by the brake cylinder device
installed on the brake caliper device, and also provided with
a pair of brake-shoe retaining portions respectively attached
to the other ends of the pair of brake levers to retain the

brake shoe and a brake-shoe attaching structure for attaching
the brake shoe to the brake-shoe retaining portion, the
brake-shoe retaining portion is provided with a key groove formed
in such a manner that a key portion formed on the brake shoe
to be attached and detached runs along downward in a
perpendicular direction, the brake-shoe attaching structure
is provided with a latch supported so as to swing below the
brake-shoe retaining portion, urged by a spring to the axial
direction and locked with the key portion, thereby supporting
the brake shoe, a snap pin inserted below the brake-shoe
retaining portion to regulate the latch swung in a direction
in which the brake shoe is unlocked from the latch, and a coupling
chain for coupling the latch with the snap pin.
[0033]
According to the present invention, such a structure is
provided that the brake shoe can be easily attached or detached
by using a latch urged by a spring (for example, a flat spring)
in a direction different from that in which the brake shoe is
attached or detached. Then, it is possible to prevent the latch
from being unlocked only by inserting the snap pin below the
brake-shoe retaining portion. In other words, in performing
work of exchanging the brake shoe, the snap pin is removed,
thereby allowing the latch to be unlocked, the latch is turned

against the flat spring or the like, with a possible drop of
the brake shoe taken into account, thus making it possible to
securely remove the brake shoe. Then, even at attachment of
a new brake shoe, the latch is locked by the flat spring or
the like at a stage where the key portion of the brake shoe
is allowed to slide on the key groove of the brake-shoe retaining
portion and arrives at a predetermined position. Therefore,
the new brake shoe can be easily attached. Further, the latch
is coupled with the snap pin by using a coupling chain, thereby
easily providing a constitution for preventing the removal or
loss of the snap pin.
As a result, a brake caliper device is provided, which
is free of an inadvertent drop of the brake shoe, realizing
work of exchanging the brake shoe easily so that support only
by the brake shoe can be released at any time, and also eliminating
the necessity for troublesome and skilled work in tightening
bolts by using a bundling wire in attaching the brake shoe.
BRIEF DESCRIPTION OF THE DRAWINGS
Other and further objects, features and advantages of
the invention will appear more fully from the following
description taken in connection with the accompanying drawings
in which:

Fig. 1 is a schematic diagram of a brake caliper device
for railway vehicles related to an embodiment of the present
invention, when viewed axially.
Fig. 2 is a schematic diagram of the brake caliper device
given in Fig. 1, when viewed from a brake cylinder device parallel
with a direction in which a vehicle advances.
Fig. 3 is a schematic diagram of the brake caliper device
given in Fig. 1, when viewed from below.
Fig. 4 is a perspective view of a brake pad used in the
brake caliper device given in Fig. 1.
Fig. 5 covers a plan view of the brake pad given in Fig.
4 and a sectional view of the brake pad indicated by the arrow
A to A..
Fig. 6 is a sectional view of the brake cylinder device
used in the brake caliper device given in Fig. 1.
Fig. 7 is a drawing including a partial sectional view
showing a partition of the brake caliper device and a guide
member of the outer cylinder member given in Fig. 6.
Fig. 8 is a drawing of a manual opening mechanism used
in the brake caliper device given in Fig. 6.
Fig. 9 is a sectional view, which shows a plurality of
different cross sections covering only half the;cross section
of the brake cylinder device given in Fig. 6, which is divided

at the center of the shaft.
Fig. 10 is an enlarged sectional view showing a ventilation
tube of the brake cylinder device given in Fig. 9 and the vicinity
thereof.
Fig. 11 covers a front elevational view.and a side view
of a filter arranged inside the ventilation tube given in Fig.
10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034]
Hereinafter, an explanation will be made for executing
the best mode of the present invention by referring to the
drawings. In addition, a brake cylinder device and a brake
caliper device having the brake cylinder device related to
embodiments of the present invention will be explained by
exemplifying a case where they are used as a brake mechanism
for railway vehicles. Constituents of each drawing are
depicted at an accuracy corresponding to that used in a design
drawing.
[0035]
Fig. 1 is a schematic diagram of a brake caliper device
1 for railway vehicles related to an embodiment of the present
invention, when viewed axially. Fig. 2 is a schematic diagram

of the brake caliper device 1 given in Fig. 1, when viewed from
a brake cylinder device 2 parallel with a direction in which
a vehicle advances. Fig. 3 is a schematic diagram of the brake
caliper device 1 given in Fig. 1, when viewed from below. As
shown in Fig. 1 to Fig. 3, the brake caliper device 1 of the
present embodiment is a disc brake-type brake mechanism.
[0036]
The brake caliper device 1 shown in Fig. 1 to Fig. 3 is
provided with a brake cylinder device 2, a caliper body 11
equipped with the brake cylinder device 2 and attached so as
to make a relative movement axially with respect to a vehicle
truck 100, a pair of backplates (brake-shoe retaining portions)
12, 12 for retaining respectively a pair of brake pads (brake
shoes) 14, 14, a pair of brake-shoe attaching structures 13,
13 for attaching respectively the brake pads 14, 14 to the pair
of back plates 12, 12, a leg 18 placed below the back plate
12, and a parallel guiding mechanism 23 placed below the caliper
body 11.
[0037]
The brake caliper device 1 is designed to generate a braking
force by holding a circular plate-like brake disc 15, which
is a disc on the shaft rotating in association with rotating
wheels of a railway vehicle (not illustrated) , between the pair

of brake pads 14, 1.4 attached to the caliper body 11 via the
back plate 12, upon actuation of the brake cylinder device 2.
In other words, the brake disc 15 is formed in a circular plate
shape having front/back braking surfaces 15a, 15a formed so
as to be orthogonal to the rotational shaft, the brake cylinder
device 2 is actuated, by which the brake pads 14, 14 are pressed
so as to hold the brake disc 15 between both sides thereof with
respect to the braking surfaces 15a, 15a from a direction
substantially parallel with a direction of the rotating shaft
of the brake disc 15 (a direction perpendicular to the space
in Fig. 1). .
[0038]
As shown in Fig. 1 to Fig. 3, the caliper body 11 is provided
with a binding member 16 and a pair of brake levers 17, 17.
The binding member 16 is attached to a bracket 100a fixed on
the bottom of a truck via a swinging pin 16a so as to swing
around the shaft parallel with a direction in which a vehicle
advances. Then, a pair of brake levers 17, 17 are mounted so
as to swing via a pair of fulcrum pins 17a approximately
symmetrical to the binding member 16. The fulcrum pin 17a is
mounted so as to extend toward a perpendicular direction, when
viewed from the top, with respect to an axial direction of the
swinging pin 16a.

[0039]
The pair of brake levers 17, 17 are constituted so that
one end thereof is provided with a brake cylinder device 2 via
a cylinder support pin 12a and driven by the brake cylinder
device 2 . Then, the pair of brake levers 17, 17 are respectively
provided with a pair of back plates 12, 12 for retaining the
brake pad 14 on the other end via the fulcrum pin 17a with respect
to one end to which the brake cylinder device 2 is attached.
The back plate 12 is attached, to the brake lever 17 so as to
swing via the support pin 12a extending parallel with the fulcrum
pin 17a. Further, a leg 18 installed so as to project in a
rectangular solid shape is providedbelow each of the backplates
12. The leg 18 is designed for the projected length so as to
correspond in dimensions to the lower end of the cylinder support
pin 17b, with consideration given in such a manner that the
end of the leg 18 and the lower end of the cylinder support
pin 17b are arranged on a plane, which is substantially parallel.
Therefore, when the brake caliper device 1 is removed from a
truck 100 and placed on a horizontal floor or the like in
performing maintenance work or the like, the end of the leg
18 and the lower end of the cylinder support pin 17b are placed
on the ground, thus making it possible to mount horizontally
the brake caliper device 1.

[0040]
Fig. 4 is a perspective view of the brake pad 14, an'd
Fig. 5 covers a plan view of the brake pad 14 (Fig. 5 (a) ) and
a sectional view indicated by the arrow A to A thereof (Fig.
5 (b) ) . As shown in Fig. 3 and Fig. 4, the brake pad 14 is formed
so as to substantially run along a part of the circular arc
of the brake disc 15, and a key portion 14a is formed on the
side opposite to a surface in contact with the brake disc 15.
Then, as clearly shown in Fig. 5, the back plate 12 is provided
with a key groove 12b formed in a shape substantially in agreement
with an outer shape of the key portion 14a in such a manner
that the key portion 14a of the key pad 14 to be attached or
detached runs along downward in a perpendicular direction.
Thereby, a brake pad 14 is attached to the back plate 12 in
such a manner that the key portion 14a is fitted into the key
groove 12b, while sliding thereon.
[0041]
As clearly shown in Fig. land Fig. 3, abrake-shoe attaching
structure 13, which is to attach to the back plate 12 the brake
pad 14 kept in a state that the key portion 14a is fitted into
the key groove 12b, is installed below the back plate 12. The
brake-shoe attaching structure 13 is provided with a latch 19,
a snap pin 20, a coupling chain 21 and others.

[0042]
The latch 19 is a narrow flat plate-like member arranged
on a surface perpendicular to the brake disc 15 and supported
pivotally so that one end thereof can swing below the back plate
12 via a pin (not illustrated) . Further, as clearly shown in
Fig. 3, a projected portion 19a shaped so as to be substantially
fitted into the key groove 12b is formed on the side facing
to the brake pad 14 of the latch 19, and the projected portion
19a is in contact with the lower end surface of the key portion
14a, thereby preventing the brake pad 14 from falling down.
Then, the end 19b on the other end of the latch 19 is pulled
outwardly (in a direction opposite to the brake disc 15), by
which the projected portion 19a of the latch 19 is unlocked
from the key portion 14a of. the brake pad 14. Further, the
latch 19 is urged axially by a flat spring 22 supported on the
leg 18 in a cantilever manner on the same side as that supported
pivotally so as to swing, thereby locking in the key portion
14a to support the brake pad 14.
[0043]
As clearly shown in Fig. 1 and Fig. 3, the snap pin 20
is formed by procedures in which one piece of a rigid wire rod
is bent in a coil shape approximately one and half times to
form a spring portion 20a, and only one end of the spring portion

20a is thereafter bent in a wave shape to form a curved portion
20b. Further, a linear portion 20c is installed on the other
end in which the curved portion 20b of the snap pin 20 is not
formed. The linear portion 20c is inserted into a pin hole
made below the back plate 12, and the snap pin 20 is inserted
into the back plate 12 so that the curved portion 20b is also
fitted into a groove portion provided below the back plate 12.
With such a constitution, when the snap pin 20 is inserted into
the back plate 12 in a state that the latch 19 is locked with
the brake pad 14, the latch 19 is to be positioned so as to
be held between the curved portion 20b and the linear portion
20c. Thereby, the snap pin 20 is inserted below the back plate
12, thus regulating the latch swung in a direction in which
the brake pad 14 is unlocked from the latch 19, and preventing
the brake pad 14 from being unlocked from the latch 19.
[0044]
The snap pin 20 is attached to the latch 19 by a coupling
chain 21 installed so as to couple the snap pin 20 with the
latch 19. That is, one end of the coupling chain 21 is fixed,
for example, by being bound to one site of the latch 19, whereas .
the other end thereof is attached to the spring portion 20a
of the snap pin 20. The snap pin 20 is required to be removed
at every exchange of the brake pad 14. Further, the snap pin,

which is small and easily lost, can be easily made
loss-preventive when having a coupling chain 21. The coupling
chain 21 is a flexible continuous body and may include any type
of thread as long as they are not likely to break after prolonged
use, for example, wire and resin threads ##wire?##.
[0045]
As clearly shown in Fig. 1 and Fig. 3, the parallel guiding
mechanism 23 is provided with a pair of guide members 24a, 24b
and a pair of guide rods 25a, 25b. The guide members 24a, 24b
are respectively provided with a U-shaped curved portion, with
one end thereof fixed to the back plate 12. Then, one end of
the guide rod 25a is fixed to the other end of the guide member
24a, whereas the. other end of the guide rod 25a is fitted into
a through-hole formed on the other end of the guide member 24b
in a loosely fitted state. In a similar manner, one end of
the guide rod 25b is fixed to the other end of the guide member
24b, whereas the other end of the guide rod 25b is fitted into
a through-hole formed on the other end of the guide member 24a
in a loosely fitted state. Further, the guide rod 25a and the
guide rod 25b are arranged parallel with each other. When the
brake cylinder device 2 is actuated by a parallel guiding
mechanism 23 composed of the pair of guide members 24a, 24b
and the guide rods 25a, 25b and the brake lever 17 is swung

to move in a direction in which a pair of brake pads 14, 14
come closer together with the back plate 12 (a direction in
contact with the brake disc 15), the pair of brake pads 14,
14 are guided so as to conduct approximately symmetrical motions,
with the brake disc 15 held therebetween.
[0046]
In the above-described brake caliper device 1, as will
be described later, the cylinder main body 26 of the brake
cylinder device 2 is attached to one end of the brake lever
17, whereas the push rod 28 is attached to the other end of
the brake lever 17, and the brake cylinder device 2 is operated
to project or retract the push rod 28. Thereby, the vicinity
of the cylinder support pin 17b for a pair of brake levers 17,
17 is driven so as to space away from or come closer to each
other. Therefore, the pair of brake levers 17, 17 act on the
basis of the fulcrum pin 17a in such a manner so as to hold
the brake disc 15 between the brake pads 14. At this time,
in the pair of brake levers 17, 17, the brake pad 14 installed
on one end of the brake lever 17 is in contact with the braking
surface 15a of the brake disc 15 earlier. Then, the other brake
lever 17 utilizes a reaction force received from the brake pad
14 in contact with the braking surface 15a, thereby pressing
the brake pad 14 on the braking surface 15a of the brake disc

15. Therefore, the brake disc 15 is held between the pair of
brake pads 14, 14, and a frictional force generated between
the brake pads 14, 14 and the braking surfaces 15a, 15a is used
to brake the rotation of the brake disc 15 and also the rotation
of wheels of a railway vehicle installed coaxially with the
brake disc 15.
[0047]
Next, an explanation will be made in detail for a brake
cylinder device 2 of the present invention. The both ends of
the brake cylinder device 2 are respectively coupled with
cylinder support pins 17b in the braking direction. Then, as
shown in Fig. 6, which is a sectional view of the brake cylinder
device 2, the brake cylinder device 2 is provided with a cylinder
main body 2 6, a normal brake means 27, a push rod 28, a spring
brake means 29, a proj ected length adjusting means 30 and others .
[0048]
The cylinder main body 26 is constituted with a first
casing portion 31 and a second casing portion 32 to form an
inner space 26a. Constitutions such as the normal brake means
27, the push rod 28, the spring brake means 29, and the projected
length adjusting means are arranged in such a manner that some
or all of them can be accommodated in the inner space 2 6a.
Further, the first casing portion 31 is provided with a bottom

and formed approximately in a cup shape (cylindrical shape),
and the second casing portion 32 is fixed by using a bolt 33
so as to close an opened side of the first casing portion 31.
Thereby, the inner space 26a is formed. Further, the end of
the first casing portion 31 is coupled with the brake lever
17 by the cylinder support pin 17b.
[0049]
The normal brake means 27 is primarily constituted with
a first spring 34, a first pressure chamber 35, and a first
piston 36. The first piston 36 is arranged so as to separate,
the inner space 26a, fitted hermetically into the inner
circumferential surface of the first casing portion 31 and also
arranged so as to slide axially on the first casing portion
31. The first pressure chamber 35 is constituted with spaces
partitioned by the first piston 36 and the first casing portion
31. A cup packing 38 is adhered on the first piston 36 in order
to improve the hermetic state of the first pressure chamber
35. Then, the cylinder main body 26 is provided with a first
pressurized fluid channel 37 communicated to the first pressure
chamber 35, and compressed air as a pressurized fluid, which
is a working fluid, is fed via the first pressurized fluid channel
37 to the first pressure chamber 35. In addition, a first
feed/discharge port 37a, which is opened from the first

pressurized fluid channel 37 to the outside of the cylinder
main body 26 and to which the compressed air is fed and discharged,
is arranged so as to position below a swinging pin 16a (refer
to Fig. 1 and Fig. 2) in a perpendicular direction.
[0050]
Further, the first spring 34 is arranged on the inner
space 26a opposite to the first pressure chamber 35 via the
first piston 36 and placed so as to urge the first piston 36
toward the first pressure chamber 35. According to the above
constitution, an urging force of the first spring 34 and the
pressure from the first pressure chamber 35 act on the first
piston 36 reversely, compressed air is fed to the first pressure
chamber 35, by which the first piston 36 makes a relative movement
with respect to the cylinder main body 26 against the urging
force of the first spring 34, and the normal brake means 27
moves in the braking direction (a direction indicated by the
arrow A in Fig. 6).
[0051]
The push rod 28 is formed in a cylindrical shape having
a shaft hole extending parallel with a direction in which the
first piston 36 moves, and a female thread 39 is made in the
vicinity of the end of the first pressure chamber 35 on the
inner circumferential surface of the shaft hole. Further, the

push rod 28 is provided on the outer circumferential surface
with an uneven surface 4 0 f ormedby repeatedly arranging recesses
and projections in a direction in which the push rod 28 moves.
In addition, a difference in height of the recesses and
projections on the uneven surface 40 is, for example, about
0.3 mm. The uneven surface 40 is a part of the constitution
forming the projected length adjusting means 30. Further, the
cylinder support pin 17b of the brake lever 17 is coupled with
the leading end of the push rod 28 via a coupling member 41,
thus making it possible to transmit a driving force of the brake
cylinder device 2 to the brake lever 17 of the caliper body
11. In addition, the coupling member 41 is fixed to the push
rod 28 by using a pin or the like in order to prevent a relative
axial rotation. Further, there is mounted a flexible
bellows-like cover 46 for dust prevention between the push rod
28 and the second casing portion 32 in such a manner so as to
cover an opening portion formed on the end opposite to first
casing portion 31 of the second casing portion 32 . In addition,
the push rod 28 is installed so as to move together with the
first piston 36 via the projected length adjusting means 30,
which will be described later.
[0052]
The spring brake means 29 is primarily constituted with

a second spring 42, a second pressure chamber 43 and a second
piston 44. The second piston 44 is constituted with a
cylindrical portion 44a formed as a cylindrical body,
flange-like portions 44b, 44c installed so as to project
outwardly respectively on both ends of the cylindrical portion
44a, a cylindrical member 44d placed inside the cylindrical
portion 44a and others, with the push rod 28 arranged so as
to penetrate through the cylindrical portion 4 4a . In addition,
the flange-like portion 44b is constituted with a plurality
of members and arranged at the leading end of the push rod 28,
whereas the flange-like portion 44c is usually arranged on the
first piston 36 . The cylindrical member 44d is integrated with
the cylindrical portion 44a and the flange-like portions 44b,
44c by a fixing ring 67 to be described later. Further, the
second casing portion 32 is provided with a spring seat 32a,
which is projected inwardly along the inner circumference
thereof like a brim to constitute a base of the second spring
42. Then, the inner circumferential end of the spring seat
32a contacts slidingly with the outer circumference of the
cylindrical portion 44a of the second piston 44 in a hermetic
manner, and the second piston 44 is arranged so as to slide
axially on the second casing portion 32.
[0053]

The second pressure chamber 43 is constituted with spaces
partitioned by the outer circumference of the cylindrical
portion 44a of the second piston 44, the inner circumferences
of the flange-like portion 44c and the second casing portion
32, and the spring seat 32. Then, the second casing portion
32 ig provided with a second pressurized fluid channel 45
communicated to the second pressure chamber 43, and compressed
air (a pressurized fluid) is fed via the second pressurized
fluid channel 45 into the second pressure chamber 43. In
addition, a second feed/discharge port 45a, which is opened
from the second pressurized fluid channel 45 to the outside
of the cylinder main body 26 and through which compressed air
is fed and discharged, is arranged so as to position below a
swinging pin 16a (refer to Fig. 1 and Fig. 2) in a perpendicular
direction.
[0054]
Further, the second spring 42 is installed as a coil spring
arranged around the cylindrical portion 44a of the second piston
44 and arranged between the spring seat 32a and the flange-like
portion 44b. As described above, the second spring 42 is placed
so as to urge the flange-like portion 44b against the spring
seat 32a (specifically, urging the second piston 44 against
the cylinder main body 26) in the braking direction (direction

indicated by the arrow A in the drawing) . Therefore, an urging
force of the second spring 42 and the pressure from the second
pressure chamber 43 act reversely on the second piston, and
the spring brake means 29 changes from a state that compressed
air is fed to the second pressure chamber 43 to a state that
it is discharged, thereby the second piston 44 is moved in the
braking direction by the urging force of the second spring 42.
In addition, the spring brake means 29 is to urge the push rod
28 via the normal brake means 27 when movement of the second
piston 44 in the braking direction occurs, as will be described
later.
[0055]
The projected length adjusting means 30 is constituted
with an outer cylinder member 47, a shaft rod 48, a guide member
49, the above-described uneven surface 40, an O-ring (elastic
member) 50, a recess 51, a partition (regulating means) 52,
and others. The projected length adjusting means 30 is
installed as a mechanism for adjusting at braking operation
a projected length of the push rod 28 from cylinder main body
26 at the time of releasing the brakes in a direction in which
the first piston 36 moves.
[0056]
The outer cylinder member 47 is formed in a cylindrical

shape, the base end of which is fixed to the first piston 36
via a flange plate 53 and a bolt 54, and constituted so as to
move together with the first piston 36. A head flange 55 is
accommodated into the base end of the outer cylinder member
47. A tapered narrowed portion 56 is formed on the inner
circumferential surface at the axial end of the outer cylinder
member 47 . The narrowed portion 56 can be used to press a radial
outer edge of the head flange 55 to the leading end (the side
in which the push rod 28 advances) . Further, a press pin 57
is installed on the outer cylinder member 4 7 so as to project
inwardly, and the leading end of the press pin 57 can be used
to press the head flange 55 to the base end (the side in which
the push rod 28 retracts).
[0057]
Further, the outer cylinder member 47 is placed between
a guide member 4 9 arranged around the push rod 28 and the second
piston 44, inside which the guide member 4 9 is arranged. Then,
the outer cylinder member 4 7 is provided with a stopper ring
58 attached to an outer circumference of the leading end thereof,
and an inner circumferential portion at the leading end of the
cylindrical member 44d of the second piston 44 is locked with
the outer cylinder member 47 via the stopper ring 58. Thereby,
when the spring brake means. 29 is actuated after a temporary

actuation of the normal brake means 27, the second piston 44
is locked with the outer cylinder member 47 via the stopper
ring 58 when movement of the second piston 4 4 to the braking
direction occurs, thus urging the push rod 28 via the outer
cylinder member 47 and the first piston 36 of the normal brake
means 27.
[0058]
The shaft rod 48 is provided on the outer circumferential
surface with a male thread 59 made threaded and mounted in a
state of being screwed with a female thread 39 made threaded
in the vicinity of the end of the first pressure chamber 35
on the inner circumferential surface of the push rod 28. The
shaft rod 48 is screwed into the shaft hole of the push rod
28, by which the push rod 28 is attached to the shaft rod 48.
Further, the. base end located on the first pressure chamber
35 in the shaft rod 48 is fixed to a head flange 55, and the
shaft rod 48 is constituted so as to move together with the
first piston 36.
[0059]
The guide member 4 9 is formed in a cylindrical shape and
supported outside the shaft rod 48 so as to rotate freely via
a thrust bearing (bearing) 60. Further, an urging spring 63
is laid between the guide member 4 9 and the head flange 55.

Then, the guide member 49 is provided with a stepped shaft hole
for inserting the push rod 28 thereinto, and an O-ring
accommodating space 49a, which is a space for opening the uneven
surface 40 and in which an O-ring 50 is arranged, is formed
at a site of the shaft hole formed in a major diameter. In
other words, the O-ring accommodating space 4 9a is formed at
a site between the bottom of the major diameter (stepped portion)
4 9b on the guide member 4 9 and a stopper ring 61 fitted into
the opening end of the major diameter, with the inner side (the
side facing to the uneven surface 40 of the push rod 28) being
opened.
[0060]
The O-ring 50 is arranged at the O-ring accommodating
space 49 between the push rod 28 and the guide member 49. Then,
aplurality (four) of O-rings 50 are arranged side by side axially
at the O-ring accommodating space 49a, and a back-up ring 62
is arranged at both ends of each of the O-rings 50 (between
adjacent O-rings 50) . Further, the bottom 49b and the stopper
ring 61 are positioned in relation to the width of the O-ring
50 in such a manner that the O-ring 50 undergoes an elastic
deformation as it is crushed to some extent between the bottom
49b of the major diameter on the guide member 49 and the stopper
ring 61. Thereby, the O-ring 50 is deformed so as to expand

to the inner circumference and engaged with the uneven surface
40 on the outer circumferential surface of the push rod 28,
by which the guide member 49 is coupled with the push rod 28.
As described above, the guide member 4 9 can move together with
the push rod 28 and is attached to the push rod 28 in such a
manner that a predetermined resisting force is applied when
the push rod 28 makes a relative movement parallel with a
direction in which the first piston 36 moves. Then, when a
force exceeding a predetermined level is applied to the guide
member 49, the 0-ring 50 is deformed to ride over a projection
of the uneven surface 40, by which the push rod 28 is displaced
with respect to the guide member 49. In addition, in the present
embodiment, an 0-ring having a diameter of approximately 5 mm
and a substantially circular cross section is used as the elastic
member due to the fact that it is easily available and relatively
high in dimensional accuracy. However, an elastic member
mainly made with rubber or the like and having an oval or a
rectangular cross section may be used.
[0061]
Fig. 7 shows the partition 52, the outer cylinder member
4 7 and the guide member 4 9 when viewed in a direction indicated
by the arrow B to B in Fig. 6. The outer cylinder member 4 7
and the guide member 49 are illustrated in cross section. As

shown in Fig. 6 and Fig. 7, the recess 51 is installed as a
groove-like portion formed in a partially recessed manner on
a circumference wall of the guide member 4 9 and extended short
in circumferential and axial directions, and provided at a
plurality (two) of sites on the guide member 49.
[0062]
Further, as shown in Fig. 6 and Fig. 7, the partition
52 is placed between the second piston 44 and the first spring
34, and installed in such a manner so as to separate a region
where the normal brake means 27 is placed from that where the
spring brake means 29 is placed inside the cylinder main body
26. Then, the partition 52 is provided with an engaging portion
64, which is engaged with the recess 51 installed on the guide
member 49. The engaging portion 64 is engaged with the recess
51 in an axial direction of the guide member 49, thereby
regulating a movable range (stroke) of the guide member 49 in
a direction in which the first piston 36 moves. Further, the
engaging portion 64 is engaged with the recess 51 in a
circumferential direction of the guide member 49, thereby also
regulating a movable range of the guide member 4 9 in a rotational
direction in which a direction of moving the first piston 36
is given as a direction of the rotational shaft (to function
as a detent) . In addition, the engaging portion 64 is provided

at a plurality of sites (two) on the partition 52 so as to
correspond to each of the recesses 51. Further, an opening
is provided at a site corresponding to the recess 51 on the
outer cylinder member 47, and the engaging portion 64 is engaged
with the recess 51 through the opening.
[0063]
Still further, the partition 52 is provided at the center
with an opening portion 65, through which the guide member 49
penetrates, and an engaging portion 64 is installed on the edge
of the opening portion 65. The opening portion 65 is formed
in such dimensions that a clearance covering all over the
circumference is allowed to exist between an outer diameter
of the guide member 49 (outer diameter perpendicular to an axial
direction of the guide member 4 9) and the edge of the opening
portion 65 so that the guide member 49 can penetrate through
an opening portion 65 without engagement of the recess 51 with
the engaging portion 64 at assembly of the brake cylinder device
2. As clearly shown in Fig. 7, in the brake cylinder device
2, the partition 52 and the guide member 4 9 are placed in such
a manner that a radial center position of the guide member 49
can be made eccentric to that of the opening portion 65 of the
partition 52
[0064]

In addition, the spring brake means 29 is provided with
a manual opening mechanism 66 for releasing manually a state
that the brakes are in operation. The manual opening mechanism
66 is constituted with a fixing ring 67, a closing member 68,
a fixing rod 69, a return spring 70 and an operation ring 71.
Fig. 8 is a sectional view showing the manual opening mechanism
66 and a constituent arranged inside the fixing ring 67. In
addition, the cross section indicated by the arrow C in Fig.
8 corresponds to the cross section given in Fig. 6. In Fig.
8, these constituents such as the fixing rod 69, the return
spring 70 and the operation ring 71 are enlarged for illustration
in larger dimensions than other constituents.
[0065]
As shown in Fig. 7 and Fig. 8, the fixing ring 67 is formed
as a C-type slit-equipped ring, and head portions 67a, 67a having
a wedge-shaped outer surface are formed on both ends opposing
each other via the slit. The fixing ring 67 is set and arranged
at the flange-like portion 44b of the second piston 44. Then,
the fixing ring 67 is, as will be described later, urged by
the closing member 68 and the fixing rod 69 to reduce in diameter,
fitted into an annular groove 72 formed on the outer
circumference of the cylindrical member 4 4d and engaged with
the annular groove 72. With such a constitution, the fixing

ring 67 is engaged with the annular groove 72, by which the
cylindrical member 4 4d of the secondpiston 44 is fixedto another
member of the secondpiston 44 and formed in an integrated manner.
[0066]
The closing member 68 is provided with an open U-shaped
cross section and constituted as a member having two inclined
surfaces in contact with wedge-shaped outer surfaces of the
head portions 67a, 67a of the fixing ring 67 formed on the inside.
The closing member 68 is guided along a predetermined groove
at the second piston 44 and thereby placed so as to move to
the fixing ring 67 in the radial direction. Further, the fixing
rod 69 is constituted as a shaft-like stepped member having
a wedge-shaped taper surface 69a at the leading end and placed
so as to move back and forth on the second piston 44. Still
further, the return spring 70 is installed as a coil spring
placed around a minor diameter portion of the stepped fixing
rod 69, and arranged between a stepped portion of the fixing
rod. 69 and a spring washer 73. The return spring 70 is placed
as described above, by which the fixing rod 69 is urged by the
return spring 70, and the fixing rod 69 presses the closing
member 68 toward the radial center of the fixing ring 67 in
such a manner that the taper surface 69a on the leading end
of the fixing rod 69 rides over outside the closing member 68.

Therefore, the closing member 68 is pressed, by which the fixing
ring 67 is kept reduced in diameter and the cylindrical member
44d at the second piston 44 is in a state of being integrated
into the second piston 44.
[0067]
Further, the operation ring 71 is attached to the end
opposite to the tapered surface 69 of the fixing rod 69. The
operation ring 71 is pulled toward a direction in which it moves
away from the spring washer 73 against an urging force of the
return spring 70, thereby giving a gradual release to a pressed
state of the closing member 68 by the fixing rod 69 so as to
ride over the closing member 68 . In association with the release
operation, the closing member 68 can move to the fixing ring
67 radially outwardly, while slidingly in contact with the
tapered surface 69a of the fixing rod 69. Thereby, the fixing
ring 67 is increased in diameter, and the closing member 68
is urged to the fixing ring 67 radially outwardly by the
wedge-shaped outer surfaces of head portions 67a, 67a of the
fixing ring 67 to release an engagement state of the fixing
ring 67 with the annular groove 72 . At release of the engagement
of the fixing ring 67 with the annular groove 72, a cylindrical
member 44d coupled with other members is decoupled at the second
piston 44 (an integrated state is released), a part excluding

the cylindrical member 44d at the second piston 44 is allowed
tomove independently of the cylindrical member 44d. Therefore,
the operation ring 71 is pulled in a state that the spring brake
means 29 is in operation, thus making it possible to develop
a state that the urging force of the second spring 42 is not
applied to the push rod 28 via the second piston 44. In other
words, when the operation ring 71 is pulled, the push rod 28
is allowed to move in a direction in which the brakes are released
together with the cylindrical member 4 4d locked by the stopper
ring 58, the outer cylinder member 47, the shaft rod 48 and
the first piston 36, even if the second piston 44 is urged by
the second spring 42 toward a braking direction. It is,
therefore, possible to release a state that the brakes are in
operation.
[0068]
Still further, the brake cylinder device 2 is provided
with a ventilation tube 72 communicating with the interior of
the cylinder main body 26 with the exterior thereof. Fig. 9
shows only half the cross section of the brake cylinder device
2, which is divided at the center of the shaft. In addition,
in Fig. 9, different cross sections are shown, which is divided
by the dashed line D, a region indicated by the arrow Dl
corresponds to the cross section given in Fig. 6 and a region

indicated by the arrow D2 corresponds to a cross section
different from that given in Fig. 6. Fig. 10 is an enlarged
sectional view covering a ventilation tube 75 and the vicinity
thereof.
[0069]
The ventilation tube 75 is formed as a rubber cylinder,
which is a cylindrical elastic body with an elbow portion, and,
as shown in Fig. 9 and Fig. 10, communicating with the outside
via a ventilation portion 76 with a spring chamber 74 (a region
surrounded by an inner circumferential wall of the second casing
portion 32, a spring seat 32a, a flange-like portion 44b of
the second piston 44 and a cylindrical portion 44a) in which
the second spring 42 of the spring brake means 29 is placed.
Then, as shown in Fig. 10, the ventilation tube 75 is provided
with a thread portion 75a formed as a male thread on the outer
circumference at one end thereof. The thread portion 75a is
screwed with a female thread portion 77 formed at the second
casing portion 32. In other words, the ventilation tube 75
is screwed and attached to the cylinder main body 26 at the
thread portion 75a and communicated with the interior of the
cylinder main body 26.
[0070]
Further, a filter 78 shown in Fig. 9 and Fig. 10 is attached

inside the ventilation tube 75. Fig. 11 covers a front
elevational view (Fig. 11 (a)) and a side elevational view (Fig.
11 (b)) showing only the filter 78. As shown in Fig. 11, the
filter 7 8 is provided with a circular wire netting portion 7 8a
and a frame portion 78b attached around the wire netting portion
78a. The wire netting portion 78a and the frame portion 78b
are both formed as a steel-made rigid body. As shown in Fig.
9 and Fig. 10, the filter 78 is arranged at a position
corresponding to a part which is inside a ventilation tube 75
and in which the thread portion 7 5a of the ventilation tube
75 is formed.
[0071]
Next, an explanation will be made for operations of the
brake cylinder device 2. Fig. 6 shows a state that the brakes
are not in operation, and neither the normal brake means 27
nor the spring brake means 29 is in operation. In a state that
the brakes are not in operation as shown in Fig. 6, in order
that the spring brake means 29 is not in operation, compressed
air is fed from the second feed/discharge port 4 5 to the second
pressure chamber 43, thereby the second piston 44 is kept urged
against an urging force of the second spring 42 in an anti-braking
direction, which is reverse in a direction indicated by the
arrow A in the drawing (a direction reverse to the braking

direction in which the brakes are released).
[0072]
When apredetermined valve (not illustrated) is controlled
to feed compressed air to the first feed/discharge port 37a
in a state that the brakes are not in operation as shown in
Fig. 6, the first piston 36 is pressed toward a braking direction
(a direction indicated by the arrow A in Fig. 6) against the
first spring 34, and the outer cylinder member 47 fixed to the
first piston 36 is also moved in the braking direction. Then,
the narrowed portion 5 6 formed on the inner circumferential
surface at the base end of the outer cylinder member 47 presses
the outer edge of the head flange 55, by which the head flange
55 is also moved in the braking direction and the push rod 28
coupled with the shaft rod 48 is also moved in the direction
given by the arrow A. In addition, at this time, the head flange
55 and the shaft rod 48, will not rotate but are simply pushed
by the outer cylinder member 47. Therefore, the normal brake
means 27 is actuated and the push rod 28 is pushed to advance
in the braking direction (together with the outer cylinder member
47 and the guide member 49) , thereby actuating the brake caliper
device 1.
[0073]
As described above, where a braking force of the normal

brake means 27 is applied to change a vehicle from a halt state
to a parking state as it is, a predetermined valve (not
illustrated) is controlled, with the above-described normal
brake means 27 being in operation, and compressed air sealed
at the second pressure chamber 43 is discharged from the second
feed/discharge port 45a. Thereby, the second pressure chamber
43, which acts against the urging force of the second spring
42, is released and the second piston 44 is extended by the
urging force of the second spring 42, thereby the cylindrical
member 4 4d of the second piston 4 4 is brought into contact with
a stopper ring 58 to keep a state that the second piston 44
is locked with the outer cylinder member 47. In this state,
even when the normal brake means 27 is released or compressed
air fed to the first pressure chamber 35 is discharged and the
first piston 36 is moved by the first spring 34 in an anti-braking
direction, the push rod 28 is urged by the spring brake means
29 to keep a state that the braking force is applied. In addition,
when the spring brake means 2 9 is released manually, as described
previously, an operation ring 71 of the manual opening mechanism
66 is used to release the cylindrical member 44d fixed to the
second piston 44.
[0074]
In a state that only the normal brake means 27 is actuated

to develop a braking force, with the spring brake means 2 9 kept
non-operating, a predetermined valve (not illustrated) is
controlled to discharge compressed air, which has been fed to
the first pressure chamber 35, through the first feed/discharge
port 37a, thereby the first piston 36 is pushed by the first
spring 34 in an anti-braking direction, and the outer cylinder
member 47 is also pulled in the anti-braking direction. As
a result, the head flange 55 is pressed, by a press pin 57, and
the shaft rod 48 and the push rod 28 coupled with the shaft
rod 4 8 are also pulled in the anti-braking direction and
retracted. Therefore, a state that the brakes are not in
operation is returned, as shown in Fig. 6.
[0075]
On the other hand, when a braking surface of the brake
pad 14 shows wear, a stroke of the push rod 28 is increased
which is necessary for actuating the brakes to result in a greater
stroke of the guide member 49 connected to the push rod 28 via
an O-ring 50. When the stroke exceeds a stroke regulated by
a recess 51 installed on the guide member 49 and an engaging
portion 64 of the partition 52, the engaging portion 64 is engaged
with the recess 51, thus giving a great returning force to the
guide member 49. Therefore, after the engaging portion 64 is
engaged with the recess 51, the O-ring 50 is deformed to ride

over a projection of the uneven surface 40, by which the push
rod 28 is deviated (displaced) to the guide member 49 only by
a portion corresponding to a further stroke of the push rod
28. In other words, the first piston 36 is moved toward a
projected direction (a braking direction), by which the engaging
portion 64 is engaged with the recess 51, and the first piston
3 6 is further moved toward the projected direction, thereby
the shaft rod 48, the push rod 28 and others are displaced toward
the projected direction, with only the guide member 49 remaining
as it is. In addition, in most cases, since a wear quantity
of the brake pad for each braking operation is quite small,
a displacement quantity of the push rod 28 for one time is
accordingly small to such an extent of a clearance between
projections on the uneven surface 40.
[0076]
Further, where compressed air is discharged from the first
feed/discharge port 37a to release the brakes by the normal
brake means 27 after a relative displacement takes place between
the push rod 28 and the guide member 4 9, the first piston 36
is returned by the first spring 34 toward an anti-braking
direction, and the head flange 55 is pushed toward the
anti-braking direction by the press pin 57 attached to the outer
cylinder member 47, which is pulled thereby. Then, the head

flange 55 is rotated together With the shaft rod 48 rotationally
supported by a thrust bearing 60, the shaft rod 48 is taken
out from the push rod 28, and a displacement of the push rod
28 with respect to the guide member 4 9 in an advancing direction
is absorbed by a screw movement. As a result, the push rod
28 is to project in the advancing direction only by an extent
of the above deviation. Therefore, the push rod 28 is adjusted
for the projected length and the brake cylinder device 2 can
be subsequently actuated by a normal stroke of the push rod
28.
[0077]
As described above, the brake cylinder device 2 of the
present embodiment is constituted in such a manner that the
push rod 28 moving together with the first piston 36 of the
normal brake means 27 penetrates through the second piston 44
of the spring brake means 2 9 and a predetermined resisting force
is applied between the guide member 4 9 of the projected length
adjusting means 30 and the push rod 28. Therefore, the brake
cylinder device 2, which is provided with the normal brake means
27, the spring brake means 29 and the projected length adjusting
means 30, can be made compact by preventing the device from
being complicated in mechanism and enlarged. Then, the
pro j ected length adj ustingmeans 30 is provided with a regulating

means 52 placed between the second piston 4 4 and the first spring
34, having an engaging portion 64 engaged with a recess 51 formed
on the guide member 4 9 and simply constituted so as to regulate
a movable range of the guide member. It is, therefore, possible
to regulate a range where the push rod 28 is adjusted for the
projected length and a range where it is not adjusted by.using
a simple mechanism.
[0078]
Thus, according to the brake cylinder device 2, it is
possible to provide such a constitution that is provided with
a normal brake means 27, a spring brake means 2 9 and means 30
for adjusting the projected length of the push rod 28, capable
of preventing the device from being complicated in mechanism
and enlarged and also capable of realizing means for regulating
a range where the projected length of the push rod 28 is adjusted
and a range where it is not adjusted by using a simple mechanism.
[0079]
Further, according to the brake cylinder device 2, a recess
51 and a regulating means 52 having an engaging portion 64 to
be engaged with the recess 51 are used to function also as a
detent for the guide member 49. It is, therefore, possible
to realize not only the function of regulating a movable range
in a direction in which the first piston 36 of the guide member

4 9 moves but also the function as a detent by using the single
regulating means 52, thus making the mechanism simple.
[0080]
Further, according to the brake cylinder device 2, a
plurality of pairs of the corresponding recesses 51 and the
engaging portions 64 are installed, by which loads acting on
engaging parts can be dispersed to reduce wear, which occurs
at the recesses 51 and the engaging portions 64, thereby
improving the durability.
[0081]
Further, according to the brake cylinder device 2, the
regulating means 52 is installed as a partition 52 for separating
a region of the normal brake means 27 from that of the spring
brake means 29, thus making it possible to form the regulating
means 52 in a thin flat-plate shape and also make the constitution
simple. Thus, the simply constituted regulating means 52 can
be placed so as to attain an effective use of space in the brake
cylinder device 2. Then, at assembly of the brake cylinder
device 2, a guide member 4 9 can penetrate through an opening
portion 65 of the partition 52 via a predetermined clearance
without engagement of the recess 51 with the engaging portion
64 . Therefore, the assembly can be carried out easily and with
an increased efficiency.

[0082]
Further, according to the brake cylinder device 2, it
is possible to provide easily and simply such a constitution
that the guide member 4 9 can penetrate through the opening
portion 65 of the partition 52 via a predetermined clearance
without engagement of the recess 51 with the engaging portion
64 at assembly of the brake cylinder device 2 by making the
center of the guide member 49 eccentric to the center of the
opening portion 65.
[0083]
Further, according to the brake cylinder device 2, the
projected length adjusting means 30 is constituted in such a
manner that the elastic member 50 is deformed and engaged (cut
into), thus making it possible to stabilize a frictional force
or a binding force between the push rod 28 and the guide member
49. Thereby, it is possible to adjust and control a sliding
resistance on the projected length adjusting means 30 in a simple
constitution.
[0084]
Further, according to the brake cylinder device 2, since
the push rod 28 is attached by being screwed with the shaft
rod 48 moving together with the first piston 36, it is possible
to provide such a constitution that a projected length of the

push rod 28 is absorbed by a screw movement made by the shaft
rod 48 with respect to the push rod 28. Therefore, it is possible
to provide such a constitution that prevents a positional
deviation of the first piston 36 with respect to a cylinder
main body 26 also in a state that the projected length of the
push rod 28 is adjusted, thereby keeping a capacity of the first
pressure chamber 35 substantially at a constant level.
[0085]
Further, according to the brake cylinder device 2, the
second piston 44 is locked with the outer cylinder member 47,
which is arranged between the guide member 4 9 and the second
piston 44 to move together with the first piston 36, thus making
it possible to urge the push rod 28. Therefore, the outer
cylinder member 47 constituted in a simplified shape is placed,
thus providing in a simple mechanism such a constitution that
the push rod 28 is urged via the normal brake means when movement
of the second piston 44 in the braking direction occurs.
[0086]
Further, according to the brake caliper device 1 of the
present embodiment, it is possible to provide the brake caliper
device 1, which is provided with the brake cylinder device 2
having the normal brake means 27, the spring brake means 29
and the means 30 for adjusting the projected length of the push

rod 28, preventing the device f rombeing complicated inmechanism
and enlarged, and making it possible to realize means 52 for
regulating a range where the projected length of the push rod
28 is adjusted and a range where it is not adjusted by using
a simple mechanism.
[0087]
Further, according to the brake caliper device 1, since
the first feed/discharge port 37a and the second feed/discharge
port 45a are positioned below the swinging pin 16a in a
perpendicular direction, it is possible to prevent the caliper
body 11 and the brake cylinder device 2 from generating a momentum
in a swinging direction both when feeding a pressurized fluid
via the first feed/discharge port 37a to the first pressure
chamber 35 and when feeding the pressurized fluid via the second
feed/discharge port 45a to the second pressure chamber 43.
Therefore, it is possible to prevent a localized contact of
the brake pad 14 on the brake disc 15 and also a localized wear
of the brake pad 14 in an emergency of the pressurized fluid.
[0088]
Further, according to the brake caliper device ,1, it is
possible to attach the filter 78 together with the ventilation
tube 75 only by screwing the ventilation tube 75 having the
filter 78 into the cylinder main body 26 at the thread portion

75a at the end thereof. Then, the filter 78 is placed inside
the ventilation tube 75, thereby eliminating the necessity for
providing a member or the like especially intended for attaching
the filter 78. Therefore, it is possible to easily and quickly
attach the filter 78 and the ventilation tube 75 to the cylinder
main body 26 and also perform work for attaching the filter
in a simplified manner.
[0089]
Further, according to the brake caliper device 1, the
leg 18 is appropriately set for the dimensions when the brake
caliper device 1 is removed and arranged on a floor for
maintenance work of the brake caliper device 1, thus making
it possible to keep the brake caliper device 1 horizontal on
the basis of the lower end on one end of the caliper body 11
and the leg 18. It is, therefore, possible to easily perform
the maintenance work or the like, thereby improving work
efficiency.
[0090]
Further, according to the brake caliper device 1, such
a structure can be provided that the brake pad 14 can be easily
attached or detached by using a latch 19 urged by a flat spring
22 in a direction different from that in which the brake pad
14 is attached or detached. Then, it is, possible to prevent

the latch 19 from being unlocked only by inserting a snap pin
20 below a back plate 12. In other words, in performing work
for exchanging the brake pad 14, the snap pin 20 is removed,
thereby allowing the latch 19 to be unlocked, the latch 19 is
turned against the flat spring 22, with a possible drop of the
brake pad 14 taken into account, thus making it possible to
securely remove the brake pad 14. Then, even at attachment
of a new brake pad 14, the latch 19 is locked by the flat spring
22 at a stage where the key portion 14a of the brake pad 14
is allowed to slide on the key groove 12b of the back plate
12 and arrives at a predetermined position. Therefore, the
new brake pad can be easily attached. Further, the latch 19
is coupled with the snap pin 20 by using a coupling chain 21,
thereby easily providing a constitution for preventing the
removal or loss of the snap pin 20. As a result, a brake caliper
device 1 is provided, which is free of an inadvertent drop of
the brake pad 14, realizing work of easily exchanging the brake
pad so that the support only by the brake pad 14 can be released
at any time, and also eliminating the necessity for troublesome
and skilled work in tightening bolts by using a bundling wire
in attaching the brake pad 14.
[0091]
An explanation has been so far made for embodiments of

the present invention. However, the present invention shall
not be limited to the above embodiments but may be executed
in various modifications without departing from the claims of
the patent. For example, the present invention may be executed
in the following modifications.
[0092]
An explanation has been made for the present embodiment
by exemplifying an air cylinder device actuated by air pressure
used in the brake cylinder device 2 as a driving source of the
brake caliper device 1. There is no restriction on the driving
source and may include a cylinder device actuated by hydraulic
pressure or others.
[0093]
Further, there is no restriction on a constitution in
which the uneven surface 40 is formed on an outer circumferential
surface of the push rod 28 and may include a constitution in
which the outer circumferential surface is made flat and a
predetermined resisting force is given from a frictional force
imparted to the push rod 28 from an elastic member such as the
O-ring 50. In this case, the push rod 28 can be easily machined
on the outer circumferential surface, thus resulting in
reduction in machining costs. Still further, there is no
restriction in a case where recesses and projections are

repeatedly arranged on the surface of the push rod 28 in a
direction in which the push rod 2 8 moves to form the uneven
surface 40, and also included is a case where surface treatment
such as blast is given to the surface, thus making it possible
to adjust a frictional force.
[0094]
Further, there is no restriction in a case where the push
rod 2 8 is coupled with the guide member 4 9 via an elastic.member.
Also included is a case where the push rod is coupled with the
guide member by a mechanical constitution in such a manner that
a predetermined resisting force can be applied at movement of
the push rod to the guide member in parallel in a direction
in which the first piston moves, for example, a gear mechanism
having a predetermined rotational resistance is actuated,
thereby the push rod is moved to the guide member.
[0095]
Still further, an explanation has been made for the brake
cylinder device 2 of the present embodiment by referring to
a case where it is used in a disc brake-type brake caliper device
1. The present invention shall not be restricted thereto. In
other words, the brake cylinder device 2 is not restricted to
a case where it is used in a disc brake-type brake mechanism
but may be used in a disc brake-type brake mechanism in which

a brake pad is attached to the leading end of a push rod and
the brake pad is allowed to be in contact with the wheel tread,
thereby generating a braking force.
[0096]
In addition, in the present embodiment, an explanation
has been made for the projected length adjusting means 30, which
is constituted with the recess 51 installed on the guide member
49 and the regulating means 52 having the engaging portion 64
to be engaged with the recess 51. Also included is a projected
length adjusting means which is provided not with the recess
51 but with a projection, that is, that constituted with a
projection installed on the guide member 4 9 and a regulating
means having an engaging portion to be engaged with the
projection.

[Claim 1]
A brake cylinder device, which is used in a brake mechanism
for vehicles, comprising:
a normal brake means having a first piston in which an
urging force of a first spring acts reversely on the pressure
from a first pressure chamber, wherein a pressurized fluid is
fed to the first pressure chamber, thereby the first piston
moves relatively with respect to the cylinder main body against
the urging force of the first spring and moves in a braking
direction;
a push rod, which is movable together with the first piston;
a projected length adjusting means having a guide member,
which is movable together with the push rod and attached to
the push rod in such a manner that a predetermined resisting
force is applied when the push rod makes a relative movement
parallel with a direction in which the first piston moves,
wherein adjusted is a projected length of the push rod from
the cylinder main body at release of the brakes in a direction
in which the first piston moves;
a spring brake means having a second piston in which an
urging force of the second spring acts reversely on the pressure
from the second pressure chamber and the push rod penetrates

therethrough, wherein a state of feeding a pressurized fluid
to the second pressure chamber is shifted to a state of
discharging it, thereby the second piston is moved in the braking
direction by the urging force of the second spring and also
the push rod is urged through the normal brake means;
wherein the projected length adjusting means is provided
with a recess or a projection installed on the guide member
and also a regulating means having an engaging portion to be
engaged with the recess or the projection and placed between
the second piston and the first spring, thus regulating a movable
range of the guide member in a direction in which the first
piston moves.
[Claim 2]
The brake cylinder device as set forth in claim 1, wherein
the regulating means also regulates a movable range of the guide
member in the rotating direction around the central axis of
the first piston by engagement of the engaging portion with
the recess or the projection.
[Claim 3]
The brake cylinder device as set forth in claim 1 or claim
2, wherein the recess or the projection is installed at a
plurality of places on the guide member and the engaging portion
is installed at a plurality of places on the regulating means

corresponding individually to each of the recesses or the
projections.
[Claim 4]
The brake cylinder device as set forth in any one of claims
1 to 3, wherein the regulating means is installed as a partition
for separating a region where the normal brake means is placed
from a region where the spring brake means is placed inside
the cylinder main body,
an opening portion through which the guide member
penetrates is formed at the center of the partition,
the engaging portion is installed at an edge, which forms
the opening portion,
the opening portion is formed in such dimensions that
allows a clearance covering the entire circumference to exist
between an outer diameter of the guide member and an edge of
the opening portion so that the guide member can penetrate
through the opening portion without making an engagement of
the recess or the projection with the engaging portion at
assembly of the brake cylinder device.
[Claim 5]
The brake cylinder device as set forth in claim 4, wherein
the partition and the guide member are placed in such a manner
that a radial center position of the guide member is made

eccentric to that of the opening portion.
[Claim 6]
The brake cylinder device as set forth in any one of claims
1 to 5,
wherein the projected length adjusting means is
additionally provided with uneven surface formed by repeatedly
arranging recesses and projections on an outer surface of the
push rod in a direction in which the push rod moves and an elastic
member placed between the push rod and the guide member,
the elastic member is deformed to make an engagement with
the uneven surface, by which the guide member is connected with
the push rod,
when a force greater than a predetermined value is applied
to the guide member,
the elastic member is deformed to ride over a projection
of the uneven surface, thereby the push rod is displaced with
respect to the guide member.
[Claim 7]
The brake cylinder device as set forth in any one of claims
1 to 6,
wherein the projected length adjusting means is
additionally provided with a shaft rod, which moves together
with the first piston and to which the push rod is attached,

the push rod is formed in a cylindrical shape having a
shaft hole extending parallel with a direction in which the
first piston moves and a female thread is made at least at a
part of the inner surface of the shaft hole, and
a male thread to be screwed with the female thread is
made at least at a part of the outer surf ace of the shaft rod,
which is screwed into the shaft hole.
[Claim 8]
The brake cylinder device as set forth in any one of claims
1 to 7,
wherein the projected length adjusting means is placed
between the guide member arranged around the push rod and the
second piston and additionally provided with an outer cylinder
member in which the guide member is arranged therein to move
together with the first piston, and
the second piston is locked with the outer cylinder member
when movement of the second piston in the braking direction
occurs, by which the spring brake means urges the push rod via
the outer cylinder member and the first piston of the normal
brake means.
[Claim 9]
A brake caliper device, comprising the brake cylinder
device as set forth in any one of claims 1 to 8 and a caliper

body having the brake cylinder device and attached so as to
make a relative movement in a shaft direction with respect to
truck wheels, and
the brake cylinder device is actuated, by which a disc
on the shaft is held between a pair of brake shoes attached
to the caliper body, thus generating a braking force.

The brake cylinder device of the present invention is provided with a normal brake means, a spring brake means, a push rod, and a projected length adjusting means having a guide
member, which is movable together with the push rod and attached to the push rod in such a manner that a predetermined resisting force is applied at movement of the push rod, thereby adjusting a projected length from a cylinder main body of the push rod. The projected length adjusting means is additionally provided
with a recess installed on a guide member and a regulating means having an engaging portion to be engaged with the recess and placed between the second piston and the first spring to regulate a movable range in a direction in which the first piston of the guide member moves.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=d+wtu3/cdAuT1dnL3kM7hw==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

271211

Indian Patent Application Number

707/KOL/2008

PG Journal Number

07/2016

Publication Date

12-Feb-2016

Grant Date

09-Feb-2016

Date of Filing

10-Apr-2008

Name of Patentee

NABTESCO CORPORATION

Applicant Address

9-18, KAIGAN 1-CHOME MINATO-KU, TOKYO

Inventors:

#	Inventor's Name	Inventor's Address
1	ASANO YOSHINO	C/O KOBE PLANT, NABTESCO CORPORATION, 3-3, TAKATSUKADAI 7-CHOME, NISHI-KU,, KOBE-SHI, HYOGO 651-2271

PCT International Classification Number

F16D65/20; F16D65/095

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2007-104970	2007-04-12	Japan