Title of Invention

DEVICE TO ARREST MOTION OF AN ELEVATOR INSTALLATION

Abstract

Summary: This device for arresting the motion of an elevator installation has an overspeed governor (5) to which the movement of the elevator car (1) is transmitted by means of a governor rope (6) . The ends of the governor rope (6) are attached to a tripping lever (8) which is mounted in a pivoting manner on the elevator car (1) and which in the case of an emergency actuates a safety gear (9) mounted on the elevator car (1). An arm (11), a spring thrust plate (12), and a compensating spring (13) form an elastic rope linkage which is able to take up differing amounts of rope stretch between the suspension rope (3) and the governor rope (6). When overspeed of the elevator car (1) occurs in an upward direction, a tripping mechanism (14) of the overspeed governor (5) actuates a rope brake (15). When overspeed of the elevator car occurs in an upward direction, the overspeed governor (5) does not become jammed as it does when overspeed occurs in a downward direction, but instead the rope brake (15) is actuated by means of the tripping mechanism (14). The rope brake (15) must compensate at least the unbalanced forces on the traction sheave (2) so as to prevent further acceleration of the elevator car (1) in an upward direction. The braking force to be produced by the rope brake (15) must be at least as great as the maximum difference in the rope forces at the traction sheave (2). (Fig. 1)

Full Text

The invention relates to a device for arresting the motion of an elevator installation consisting of an overspeed governor which monitors the speed of an elevator car, the elevator car being connected by means of a suspension rope to a counterweight, and the movement of the elevator car or counterweight being transmitted by means of a governor rope to the overspeed governor which causes the motion of the elevator car to be arrested if overspeed occurs. From patent specification DE 36 15 270 C2 an overspeed governor has become known which monitors the speed of travel of an elevator car. The elevator car has a wire rope which drives a rope pulley with an integral toothed wheel. A cam wheel imparts a rocking motion to a pivoted double-arm rocker which has a lug at one end. Mounted on the double-arm rocker in a pivoting manner is an actuating lever which is kept at rest relative to the double-arm rocker by means of a restraining device. The upper end of the actuating lever takes the form of an actuating dog and at the lower end there is a tripping lug which protrudes beyond a rocker lug. The two lugs are always in a position between two teeth on the toothed wheel when the roller follower is on a lobe on the cam wheel. When the roller follower is between two lobes on the cam wheel both lugs are raised out of the path of the teeth. As a result, the teeth on the toothed wheel pass under the lugs with no effect. At overspeed, the roller follower lifts off the cam wheel. The tripping lug remains in the path of the toothed wheel. A tooth of the toothed wheel strikes the tripping lug and displaces the actuating lever. This causes the actuating dog to operate a switch which switches off the drive. If the speed of the car increases further, the rocker lug enters into the path of the toothed wheel thereby jamming the toothed wheel and the rope pulley. The friction in the rope groove creates the force to trip a safety gear. j A disadvantage of the known device is that monitoring and arrest of the elevator car take place only in a downward direction. It is in this respect that the invention aims to provide a remedy. The objective of the invention as characterized in Claim 1 is to avoid the disadvantages of the known device - and to create a device which monitors the elevator car in an upward direction and in a downward direction and brings it to a standstill in an emergency. The advantages resulting from the invention relate mainly to the fact that the releasing forces after arrest has taken place are very small. The engaged safety gear can be released by means of the available tractive capacity of the traction sheave, which is of particular significance on elevator installations having no machine room. Furthermore, the device according to the invention causes no additional load on the drive and does not give rise to excessive deceleration. The device according to the invention can be easily retrofitted on elevator installations without modifying the elevator car. Accordingly the present invention provides a device for arresting motion of an elevator consisting of an overspeed governor which monitors the speed of an elevator car connected to a counterweight by means of a suspension rope, the movement of the elevator car or counterweight being transmitted to the overspeed governor by means of a governor rope which causes the elevator installation to be arrested if overspeed occurs, characterized in that to arrest the motion of the elevator car or the counterweight if overspeed occurs in an upward direction there is a rope brake which can be actuated by means of a tripping mechanism of the overspeed governor. A more detailed description of the invention follows below by reference to drawings illustrating an embodiment. The drawings show: Fig. 1 A schematic view of an elevator installation with the device for arresting motion of the elevator installation according to the invention; Fig. 2 A schematic view of an overspeed governor for actuating a rope brake which acts on a governor rope ; Fig. 3 A schematic view of the elevator installation with an exemplary embodiment of the device according to the invention for arresting the motion of an elevator installation; and Fig. 4 A schematic view of an overspeed governor for actuating a rope brake which acts on a suspension rope. In Figs 1 to 4, number 1 designates an elevator car which can travel in an elevator hoistway (not shown), the elevator car being connected to a counterweight 4 by means of a suspension rope 3 which passes over a traction sheave 2. To monitor the speed of the elevator car 1, or the counterweight 4, there is an overspeed governor 5 which operates, for example, on the principle of a pivoted double-arm rocker, the movement of the elevator car 1 or counterweight 4 being transmitted to the overspeed governor 5 by means of a governor rope 6. Governors operating, for example, on the principle of centrifugal force or inertia can also be used to monitor the speed. The governor rope 6 extends over the entire hoistway height, and at the lower end of the hoistway its direction is reversed and tension is applied by a return pulley 7, and at the upper end of the hoistway it is led over a rope pulley of the overspeed governor. The ends of the governor rope 6 are attached to a first tripping lever 8 which is mounted in a pivoting manner on the elevator car 1 and which in the case of an emergency actuates a safety gear 9 mounted on the elevator car 1. After the elevator car 1 has been released from engagement of the safety gear, a resetting spring 10 resets the first tripping lever 8 and the safety gear 9. Mounted on the counterweight 4 is an arm 11 through which the governor rope passes. Close to the arm 11 is a spring thrust plate 12, which is rigidly fastened to the governor rope 6 and which supports a compensating spring 13 whose spring force presses it against the arm 11. The arm 11, spring thrust plate 12, and compensating spring 13 form an elastic rope linkage which is able to take up differing amounts of rope stretch between the suspension rope 3 and the governor rope 6. When overspeed of the elevator car 1 occurs in an upward direction, a tripping mechanism 14 of the overspeed governor 5 actuates a rope brake 15. When overspeed of the elevator car 1 occurs in an upward direction, the overspeed governor 5 does not become jammed as it does at overspeed in a downward direction, but instead the rope brake 15 is actuated by the tripping mechanism 14. To prevent further acceleration of the elevator car 1 in an upward direction of travel, the rope brake 15 must compensate at least the unbalanced forces on the traction sheave 2. If the braking force is higher, the system will be decelerated depending on the moment of inertia of the installation. The braking force developed by the rope brake 15 must be at least as high as the maximum difference in rope forces at the traction sheave 2. Fig. 2 shows details of the overspeed governor 5, the tripping mechanism 14, and the rope brake 15. The governor rope 6 passes over a rope pulley 17 which has a rope groove and is supported in a rotatable manner on a first axle 16. The first axle 16 is supported by a case 18. Mounted on the rope pulley 17 are a toothed wheel 19 with teeth 20, and a cam wheel 21 with lobes 22. Also mounted on the case 18 is a second axle 23 on which a double-arm rocker 24 having a follower roller 25 is mounted in a pivoting manner. At normal speed the follower roller 25 follows the surface of the cam wheel 21 with its lobes 22. At overspeed the follower roller 25 is no longer able to follow the surface of the cam due to the inertia of the double-arm rocker 24. Mounted on the opposite end of the double-arm rocker 24 from the follower roller 25 is a first lug 26 which at normal speed of the elevator car 1 enters the space between two teeth 20 of the toothed wheel when the follower roller 25 is on a cam lobe 22, and which is raised out of the path of the teeth 20 when the follower roller 25 is between two cam lobes 22. When the elevator car 1 travels at overspeed in a downward direction, the first lug 26 remains between two teeth 20, and the right-hand flank of the following tooth 20 hits the first lug 26 thereby jamming the toothed wheel 19 and with it the rope pulley 17. Due to the movement of the elevator car 1 relative to the jammed governor rope 6, the first tripping lever 8 engages the safety gear 9 and the elevator car 1 is held fast on the guiderails. At the end of the double-arm rocker 24 opposite the follower roller 25 is an actuating plate 27 which is mounted in a pivoting manner on a third axle 28 of the double-arm rocker 24. The actuating plate 27 is held stationary relative to the double-arm rocker 24 by means of a restraining device, a snapper for example. At normal speed of the elevator car 1, a second lug 29 of the actuating plate 27 enters the space between two teeth 20 when the follower roller 25 is on a cam lobe 22, and is raised out of the path of the teeth 20 when the follower roller 25 is between two cam lobes 22. When the elevator car 1 travels at overspeed in an upward direction, the second lug 29 remains between two teeth 20, and the left-hand flank of the following tooth 20 hits the second lug 29, thereby causing the actuating plate 27 to turn in a clockwise direction. The toothed wheel 19 and with it the rope pulley 17 and the governor rope 6 continue their movement. The clockwise movement of the actuating plate 27 causes a finger 30 on the actuating plate 27 to turn a second actuating lever 31 of the rope brake 15 in a counterclockwise direction about a fourth axle 32 on the rope brake 15, causing at least one brake shoe 34, which is moveable by means of at least one compression spring 33, to be released. The brake shoe 34 moves downward and is pressed against at least one opposite brake shoe 35 thereby braking the governor rope 6 which passes between the shoes 34, 35. The braking force applied to the governor rope 6 gently decelerates the elevator car 1 and the counterweight 4 and depends on the spring force of the compression spring 33, the surface of the shoes 34, 35, and the surface of the governor rope 6. Deceleration of the counterweight 4 takes place via the governor rope 6, the spring thrust plate 13, and the arm 11. Figures 3 and 4 show a device to arrest the motion of an elevator car 1 travelling at overspeed in an upward direction by means of a rope brake 15 acting on the suspension rope 3. By means of a Bowden cable 36 the movement of the second actuating lever 31, 32 is transmitted to the second actuating lever 31.1, 32.1 of the rope brake 15, the functioning of the rope brake 15 being unchanged. In a further exemplary embodiment, the overspeed governor 5 can be used as a rope brake. In this variant, when the elevator car 1 travels at overspeed in an upward direction the toothed wheel 19 is jammed by means of a further lug mounted on the double-arm rocker 24. Provided that the governor rope 6 is very tightly pretensioned, the friction of the governor rope 6 in the rope groove specially formed for this purpose in the rope pulley 17 which is jammed, creates a sufficiently large braking force. The overspeed governor 5 with the double-arm rocker 24 and the first lug 26 which is used to check for overspeed of the elevator car 1 in a downward direction can also be modified to check for overspeed of the elevator car 1 in an upward direction. Mounting the actuating plate 27 and the rope brake 15 is easily carried out. WE CLAIM: 1. A device for arresting motion of an elevator consisting of an overspeed governor (5) which monitors the speed of an elevator car (1) connected to a counterweight (4) by means of a suspension rope (3), the movement of the elevator car (1) or counterweight (4) being transmitted to the overspeed governor (5) by means of a governor rope (6) which causes the elevator installation to be arrested if overspeed occurs, characterized in that to arrest the motion of the elevator car (1) or the counterweight (4) if overspeed occurs in an upward direction there is a rope brake (15) which can be actuated by means of a tripping mechanism (14) of the overspeed governor (5). 2. The device for arresting the motion of an elevator as claimed in claim 1, wherein the rope brake (15) is located on the governor rope (6), the governor rope (6) being braked by a braking device (33, 34, 35) of the rope brake (15) if overspeed of the elevator car (1) occurs in an upward direction. 3. The device for arresting the motion of an elevator as claimed in claim 1, wherein the rope brake (15) is located on the suspension rope (3), the suspension rope (3) being braked by a braking device (33, 34, 35) of the rope brake (15) if overspeed of the elevator car (1) occurs in an upward direction. 4. The device for arresting the motion of an elevator as claimed in claim 1, wherein the overspeed governor (5) serves as a rope brake, the governor rope (6) being braked by friction in a rope pulley (17) of the overspeed governor (5) if overspeed of the elevator car (1) occurs in an upward direction. 5. The device for arresting the motion of an elevator as claimed in claims 1 to 3, wherein the tripping mechanism (14) is an actuating plate (27) which is mounted on a double-arm rocker (24) of the overspeed governor (5) and which is held at rest relative to the double-arm rocker (24) by means of a restraining device and which when overspeed of the elevator car (1) occurs in an upward direction can be displaced by means of a toothed wheel (19) of the overspeed governor (5). 6. The device for arresting the motion of an elevator as claimed in claims 1 to 3, wherein the rope brake (15) has at least one spring (33), at least one break shoe (34), and at least one opposite brake shoe (35), there being a tripping lever (31) which can be actuated by the tripping mechanism (14) to release the brake shoe (34), and the rope (3, 6) being braked by brake shoes (34, 35) which are pretensioned by means of a spring. 7. The device for arresting the motion of an elevator as claimed in claim 2, wherein an elastic rope linkage (11, 12, 13) is provided to connect the counterweight (4) to the governor rope (6). 8. A device for arresting motion of an elevator substantially as herein described with reference to the accompanying drawings.

Documents:

0753-mas-99 abstract-duplicate.pdf

0753-mas-99 abstract.pdf

0753-mas-99 claims-duplicate.pdf

0753-mas-99 claims.pdf

0753-mas-99 correspondence-others.pdf

0753-mas-99 correspondence-po.pdf

0753-mas-99 description (complete)-duplicate.pdf

0753-mas-99 description (complete).pdf

0753-mas-99 drawings-duplicate.pdf

0753-mas-99 drawings.pdf

0753-mas-99 form-1.pdf

0753-mas-99 form-19.pdf

0753-mas-99 form-26.pdf

0753-mas-99 form-3.pdf

0753-mas-99 form-5.pdf

0753-mas-99 petition.pdf