Title of Invention	OVERRUNNING MECHANISM ADAPTED FOR A SYSTEM OF STORED ENERGY MOTOR OPERATION
Abstract	An overrunning mechanism with gear meshing arrangement provided with a system for stored energy motor operation for moulded case circuit breakers(MCCB) operative connection of the motor with respect to an operating shaft comprising a pinion, a gear means, a worm gear wheel, unidirectional clutch, said further gear adapted to drive final gear and the operating shaft, a crank mechanism driven ratchet coupled to the final gear of the charging mechanism through a pawl, a stationary pin lifting the pawl crank, operative slider and a cam means.

Title of Invention

OVERRUNNING MECHANISM ADAPTED FOR A SYSTEM OF STORED ENERGY MOTOR OPERATION

Abstract

An overrunning mechanism with gear meshing arrangement provided with a system for stored energy motor operation for moulded case circuit breakers(MCCB) operative connection of the motor with respect to an operating shaft comprising a pinion, a gear means, a worm gear wheel, unidirectional clutch, said further gear adapted to drive final gear and the operating shaft, a crank mechanism driven ratchet coupled to the final gear of the charging mechanism through a pawl, a stationary pin lifting the pawl crank, operative slider and a cam means.

Full Text	FORM2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title of the invention. - 2. Applicant OVERRUNNING MECHANISM ADAPTED FOR A SYSTEM OF STORED ENERGY MOTOR OPERATION (a) LARSEN & TOUBRO LIMITED b) of L & T House, Ballard Estate, Mumbai - 400 001 State of Maharashtra, India (c) An Indian Company The following specification particularly describes the nature of this invention and the manner in which it is to be performed The present application is divided out of Application No. 1032/MUM/2003 dated 03/10/2003. Field of the Invention The present invention relates to a system for stored energy motor operation for circuit breakers and in particular to a system for stored energy motor operation for moulded case circuit breakers (MCCB), which would be simple and cost-effective to obtain and safe and user friendly. More particularly the invention relates to system for stored energy motor operation being provided with a mechanism to prevent travel mismatch between the linear carriage and the operating handle by means of disc springs and provided with mechanism to prevent loss of the charging command so far supplied to the spring in the event the control power supply is lost. The system is further provided with overrunning mechanism with gear meshing. The system is also provided with freewheeling arrangement with ratchet and pawl. The system is further provided with an arrangement with stay put push button means. The system is further provided with a swivel arrangement and a strut means for retaining the mechanism in the completely swiveled out position. Background Art Moulded case circuit breakers (MCCB) usually have three stable operating positions namely "ON", "OFF" and "TRIPPED". In the ON condition, the contacts of the MCCB are closed and in the OFF position the contacts are open. The MCCB comes to the TRIPPED position in the event of an abnormal situation such as short circuit or an overload. It is also possible to even otherwise bring the MCCB to the TRIPPED position by operating a push button located on the MCCB identified as "Push- to-TRIP" button. The MCCB is further adapted for resetting from TRIPPED position to OFF position by moving its operating knob. Importantly, the above operations or switch over from the various operating positions can be effected either manually or electrically with the help of motor operator, which is fixed to the MCCB. In the presently available system, the MCCB is adapted for the above operative conditions/states by way of direct connection of the operating motor, geared to its operating knob. However, it is found that such systems required more operating time for the MCCB to actuate during change over from one state to the other. US 6130392 teaches stored energy circuit breaker actuation apparatus for closing a circuit breaker assembly in a time period of circuit breaker operation between 50 and 100 milliseconds either through manual or electrical motor operation. It comprises housing of the circuit breaker, operator handle assembly, operator gear assembly, pinion gear assembly, stored energy charging and discharging assembly, energy storage assembly comprising springs that store energy when charged and release energy when discharged circuit breaker operating handle, series of gears for electric operation, an operative switch for the motor operator, a drive shaft, reduction gear assembly/gear mesh arrangement. It further provides for electronic control by means of silicon control rectifier and is provided with indicator means for indicating status of the stored energy. An electric switch is used here. Generally, electric switches are robust in structural configuration and require high power for its own actuation. This results in the power loss of the total system and so the operation is not a cost effective one. The main charging operator gear has missing gear teeth in the order of about more than one-half of its circumference. Therefore during re-engagement of the gears phase synchronization is not maintained which gives rise to impact between the first tooth of the final gear and the worm gear arrangement. This may result in the damage of the gear arrangement. Further there is no mechanism to control the charging of spring to a definite level. Additionally the mechanism to prevent travel mismatch between the linear carriage and the operating handle comprise helical springs. However such helical springs cannot be accommodated in a compact space for high force and hence high stroke/force ratio cannot be achieved. US 6015959 teaches molded case electric power switches with cam driven, spring powered open and close mechanism: The system comprises energy storage spring, cam assembly, drive cam, latch mechanism, ratchet. The latch mechanism for control of storage of energy by the spring is further provided with Y-latch. US6153845 teaches three selective modes of breaker actuation operation namely manual locked, manual unlocked and automatic for ON, OFF and TRIP operation of the breaker handle. For manual unlocked selection of local or remote operation is needed. If local is selected ON switch and OF switch of the stored energy assembly is used to turn ON or OFF the circuit breaker assembly while for remote the circuit breaker assembly cannot be turned ON or OFF. If manual locked operation is chosen it comprising selecting local or remote operation for which the stored energy assembly is not used to turn ON or OFF the circuit breaker assembly. For automatic operation further steps of selection of local or remote operation is needed. For local operation stored energy assembly is not used to turn ON the circuit breaker assembly and stored energy assembly is used to turn OFF the circuit breaker assembly. If remote operation is selected a remote ON button is used to cause stored energy assembly to turn on the circuit breaker assembly and OFF button is used to cause stored energy assembly to turn off the circuit breaker assembly. There is no mechanism to prevent loss of the energy so far supplied to the spring if anyhow the control power supply is lost. US6166343 teaches unidirectional clutch assembly comprising unidirectional clutches to be used with an operator handle, pinion shaft assembly, worm gear assembly and pinion gear assembly of a stored energy assembly for use with a circuit breaker assembly. However there is no mechanism to absorb the impact due to re-engagement of the gears when the first unidirectional clutch means slips in one direction so that the operator handle does not move and the worm gear assembly rotates so as to rotate pinion gear assembly and when the second unidirectional clutch means slips in one direction and the pinion gear assembly does not rotate so that the operator handle does not move. Here the main gear comprising the toothless zone and used for incremental gear operation, at the time of reengagement results in impact between the first gear tooth and the worm gear. There is no mesh gear arrangement in the clutch system. US 6192718 teaches a stored energy assembly for use with a circuit breaker assembly such that the stored energy assembly is operable to locked and unlocked states. The mechanism for operating the stored energy assembly to locked and unlocked states comprises cylindrical key lock mounted on the stored energy assembly housing and at least a portion of the lock adapted to be moved to at least one unlocked and at least one locked position, a cylindrical lock arm, lifting member, locking hasp assembly. The system is complex. US 6078017 teaches an adapter plate assembly for mounting stored energy assembly to a circuit breaker assembly comprising a mounting plate comprising a circuit breaker toggle aperture, a circuit breaker trip aperture, trip arm mounting aperture, trip arm comprising a trip flange. The mounting plate of the adapter assembly has a terminal bus assembly. This makes the system complex. US 6072137 teaches a pinion gear carrier assembly for relating turning of an operator shaft by an operator handle to turning of a main operator gear for driving movement translation assembly to charge a stored energy assembly of a stored energy circuit breaker actuation apparatus. The pinion gear carrier assembly comprises a pinion gear carrier having an idler pinion gear-mounting member, driver pinion gear, an idler pinion gear mounted on the mounting member. The pinion gear carrier assembly operates a main operator gear such that the gear teeth span less than its full circumference. There is no mechanism for impact absorption between the gear and the idler, which may lead to damage of the operator gear and the idler. Moreover due to presence of toothless portion in the overrunning zone the motor is disengaged and after the spring is discharged the motor is re engaged. This leads to poor gear meshing between the gears and phase synchronization is required. A 4 further drawback of toothless overrunning mechanism is interdependence of electrical and manual charging mechanism US 6423917 teaches a motor operator for a circuit breaker. It teaches a mechanized system for manipulating an operating handle of a circuit interruption mechanism which comprises a motor drive assembly connected to mechanical linkage system which includes a recharging cam driven by the motor drive assembly for driving an energy storage system namely spring and an energy release mechanism to release the energy stored in the energy storage system. The recharging cam being coupled to drive plate and adapted to compress the spring to a predetermined value. A linear carriage coupled to the drive plate manipulates the operating handle of the circuit interruption mechanism when the spring is released from its compressed state. However there is no mechanism to prevent mismatch between the linear carriage and the operating handle, which may lead to breakage of the circuit breaker handle or no operation of the circuit breaker at the various positions. US 6559743 teaches operating mechanism for a circuit breaker. It includes a holder assembly to receive a portion of the operating handle of the circuit breaker and is capable of movement between closed and open positions of the circuit breaker. There is drive plate coupled to the holder assembly and an energy storage mechanism for a plurality of states each with defined energy level and mechanical linkage system coupled to the energy storage mechanism and the drive plate. The mechanical linkage system responds to the motor drive assembly to disengage and reengage a set of circuit breaker contacts by moving operating handle. The energy storage mechanism comprising first and second springs of definite spring constant being positioned respectively in first fixture (with slots) and second fixture (of many members) and such that the two fixtures are operatively connected. The holder assembly comprising carriage, retaining bar rotatably mounted on carriage and spring. Thus the system is a complex with the incorporation of said holder assembly and there is no mechanism for countering travel mismatch. Thus there is need to provide for a system for stored energy motor operation of moulded case circuit breakers which is simple, cost effective, provided with mechanism to prevent travel mismatch between the linear carriage and the operating handle yet having overrunning mechanism with gear meshing and provided with mechanism to prevent loss of the energy so far supplied to the spring if anyhow the control power supply is lost. Objects of the Invention Thus the basic object of the present invention is to provide a system of stored energy motor operation for circuit breakers especially moulded case circuit breakers with a mechanism to prevent travel mismatch between the linear carriage and the operating handle during breaker operation by means of disc springs of high force/stroke ratio with a fine tuning of threshold of its deflection providing a high elastic coupling limit. Another object of the present invention is to provide a system of stored energy motor operation for circuit breaker especially moulded case circuit breaker, which would provide for fast and effective change over from various states of selective electrical and/or manual operation thereby effectively reducing the operating time of the MCCB. Another object of the present invention is to provide a system of stored energy motor operation for circuit breaker such as moulded case circuit breakers adapted for electrical and/or manual operation which on one hand would effectively reduce the operating time of the MCCB and on the other hand would involve simple and cost-effective gadgets and thereby enable providing said system for stored energy motor operation for MCCB simple and easy to obtain and use. Yet further object of the present invention is directed to provide for a system for stored energy motor operation for moulded case circuit breakers wherein the same is adapted for a simple yet effective electrical charging for generating the stored energy for motor operation of the circuit breakers and would also have simple manual operative system for effective and advantageous use of the circuit breaker. Yet another object of the present invention is to provide for a system for stored energy motor operation for moulded case circuit breakers which would achieve improved operating performance in terms of reduced operating time for change over to the various states of operation and would also involve simple and cost-effective gadgets and most importantly maintaining standard requirements of such stored energy operative circuit breakers for ready and wide scale use and application of the system. Yet another object of the present invention is to provide for a system for stored energy motor operation for moulded case circuit breaker, which would ensure total spring charging thereby favoring complete and advantageous use of the stored energy in the operation of the device. Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers which would take care of problems encountered when the MCCB is brought to ON, Reset/OFF positions by the engagement of the slider of motor operator to the MCCB handle during which the travel of MCCB to this different positions can vary due to the tolerance of the components. Yet further object of the present invention is directed to provide for a system for stored energy motor operation for moulded case circuit breaker which would be adapted for automatic charging 0f spring after tripping of MCCB by means other than the local push OFF button on the motor operator. Yet further object of the present invention is directed to provide for a system for stored energy motor operation for moulded case circuit breaker which would have simple and effective manual operations for the circuit breaker handle which would not only facilitate faster and effective change over of the operative state of the circuit 7 breaker but would also ensure that the handle is maintained in the inoperative state during motorized operation of the circuit breaker. Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers, which would have simple configuration, adapted to convert axial push movement of push buttons into rotary motion of shaft and latching means avoiding multiplicity of linkages. Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers which would have standard requirement of locking of ON push buttons effectively in the locked and padlocked state and its unlocking for its operative function. Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers which would effectively provide for the required locking and pad locking of the OFF push button whereby the handle as well as OFF pushbutton movement could be prevented and the MCCB cannot be made locally OFF. Yet another object of the present invention is to provide for stored energy motor operation for moulded case circuit breakers wherein the stored energy motor operator would be adapted to access the MCCB handle to facilitate the operation of the MCCB even without the operator. Yet another object of the present invention is to provide for stored energy motor operation for moulded case circuit breakers wherein the excess energy from the springs after closing the moulded case circuit breaker does not result in impact between the gears. 8 A further object invention is to provide for stored energy motor-operation for moulded case circuit breaker, which overcomes the drawbacks of the conventional systems with regard to overrunning and adapted to use of multiple gear mesh. Another object the present invention is to provide an over-running system with separate driving points for manual charging and electrical charging and hence totally independent operation. Further one more object of the present invention there is provided a freewheeling arrangement for a system for stored energy motor operation of moulded case circuit breakers wherein the said freewheeling arrangement comprising ratchet and pawl arrangement adapted to absorb the excess energy in the spring resulting in an impact between the first tooth of the sector gear and the idler. The other object of the present invention is directed to provide for a push button with an arrangement comprising stay put means ensuring that the spring will resume charging immediately on restoration of power supply, in case during the spring charging the control supply to the motor is lost. Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers with the mechanism assembly a hinge and a strut means for holding the mechanism in the fully opened state to facilitate maintenance. Summary of the Invention According to the basic aspect of the present invention there is provided an overrunning mechanism adapted for a system for stored energy motor operation of moulded case circuit breakers, said over running mechanism comprising: operative connection of the motor with respect to an operating shaft comprising a pinion mounted on the shaft of the motor adapted to drive a gear means, a worm 9 gear wheel mounted on the axis of said gear adapted to drive a worm gear wheel, a further gear coupled to said worm gear wheel driven through unidirectional clutch .said further gear adapted to drive final gear and the operating shaft; being further adapted to be driven by a gear coupled to handle a crank mechanism driven by means of a ratchet coupled to the final gear of the charging mechanism through a pawl; such that when the springs are charged, an appropriately located stationary pin lifts the pawl and permits the charging mechanism to overrun; in operative connection with electrical operative means for selective change over of state of MCCB to ON, reset/OFF positions comprising a simple selective operative connection of the shaft of a motor to a gear system; crank operative slider means restrained by spring means wherein the rotation of crank is adapted for stretching of the spring and its charging, a cam means on the crank operatively connected to disconnect the motor by an operative switch means when the spring is stretched beyond a present dead center limit ,said slider means and the chargeable spring operatively connected to the circuit breaker handle for selective change over of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle and /or a manually operable handle means for selective change over of state of MCCB to ON, reset/OFF positions provided to charge a spring based operative slider means , said spring chargeable slider means operatively connected to the circuit breaker handle for selective change over of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle. Detailed Description Of The Invention The above combination of electrical and/or manually operable stored energy motor operable system is directed to add to the desired flexibility in operation apart from fast and effective change over from various states of selective electrical and/or manual operation and thereby effectively reduce the operating time of the MCCB. 10 The system of present invention for stored energy motor operation for circuit breakers especially moulded case circuit breakers would provide for much desired fast and effective change over from various states of selective electrical and/or manual operation and thereby effectively reduce the operating time of the MCCB and provide for absorbing the travel mismatch unlike most of the prior art systems where no such mechanism for absorbing the travel mismatch was present. A mismatch between the travel of the slider of the operator and MCCB handle can result into breakages of MCCB handle or non operation of MCCB to the said ON to OFF and vice versa positions. The present system uses elastic coupling by means of disc springs having high force/stroke ratio for which it can impart a very high force with respect to a minute displacement. On the other hand the helical spring used by US 6130392 could not be accommodated in a compact space for high force. Moreover the disc springs of the present invention further provide the coupling to be stiff yet compact unlike the prior art and also provide a high force/stroke ratio compared to the prior art. In contrast the present invention prevents the leakage in flux thereby making the breaker operation faster and yet absorbs the travel mismatch. Unlike the helical springs, which are usually used for the purpose, the disc springs have characteristics of imparting a very high force for a small deflection i.e. the force/stroke ratio in the disc spring is very high. The system of the present invention includes a plurality of disc springs, which can be accommodated in a compact space, helping to attain a fine-tuning threshold of its deflection. This helps to absorb the breaker travel mismatch and thereby prevent breakage of the handle. The excess travel of the stored energy mechanism during the toggling operation is absorbed by the elastic coupling in the form of the disc springs incorporated in the charging arrangement. The requirement of the elastic coupling is not to deflect from its initial position until the operating forces of the handle has exceeded and necessarily deflect before the breaking force of the handle is attained for which a stiff and compact coupling is required. This is easier to achieve in disc spring than the conventional helical spring. 11 Importantly, the above system on one hand would effectively reduce the operating time of the MCCB and on the other hand would involve simple and cost-effective gadgets and thereby enable providing said system for stored energy motor operation for MCCB simple and easy to obtain and use. An improved spring charging arrangement for a stored energy motor operator incorporated in moulded case circuit breaker system having a spring of definite dimensional configuration and a particular spring constant. This spring constant depends on the nature of the material used in the spring and its dimension. A plate of rectangular dimension called the slider is fixed to the spring. A crank pin is connected to slider. As the crank rotates the spring gets stretched and charges until the dead center is reached. Slightly beyond dead center if the spring is stretched, the motor is disconnected by a micro switch, which is actuated by a cam profile on the crankshaft. The stored spring potential energy can be used or transformed into mechanical energy, which may be utilized in the formation of the rotational inertia and finally the rotational torque. This rotational torque gives the moment of force to rotate the crank, which finally helps to achieve the initial operation or the toggling operation. From the plan view of the interior of the motor operator it is realizable that the conversion of mechanical energy to potential energy is incorporated by respective gearing arrangements. Even if the control supply to the motor is deactivated by some means the electrical energy till then supplied is not lost but it is stored in the form of spring potential energy. Again, on restoration of the power supply the spring resumes charging. Therefore, the storing of energy in the spring can be controlled to any limitations by an arrangement of crank gears coupled the spring through the slider arrangement. 12 As the crank rotates, the spring is stretched and thus there is gain in the spring potential energy. This energy can be kept to any value by disengaging the motor from the slider arrangement thus stopping the spring to stretch any further. The crank attached to this spring via the slider is provided with a micro switch actuated by a cam coupled to the crankshaft. When a charging/reset command is given, the rotation of the crank is stopped by a latch, which locks the crank at particular position. A suitably cam shaped profile is provided on the crank, which holds the crank against the latch. Now the energy so far stored in the spring is used to rotate the crank and perform the required operation of the motor operator. The elastic coupling between the slider and the breaker handle comprises disc springs. The disc springs are accommodated in a compact space fixed to the slider and the breaker handle, which would be troublesome if instead helical springs are used. Since the volumetric configuration of the disc spring is less than that of the helical one, so there is a reduction in the total volume of the circuit breaker case. Therefore the mass of the material used for casing is less thus reducing the cost. The most important characteristic of the disc spring is high force/stroke ratio to impart high force for a very small displacement from its initial position. This arrangement enables to absorb the travel mismatch of the motor operator and MCCB handle an elastic coupling is done in between the slider and the molded case circuit breaker by a plurality of disc spring to absorb the said mismatch. The sensitivity of the disc spring may also be considered keeping in mind the high force/stroke ratio. Due to it"s high sensitivity a fine tuning of the threshold of it"s deflection would impart a greater force on the disc spring thus raising the elastic coupling limit which compensate for the above travel mismatch. An overrunning mechanism is provided in combination with the charging mechanism for a stored energy motor operator. The crank is driven by means of a pawl. The 13 pawl is coupled to the final gear of the charging mechanism through a ratchet, which is a pivoted catch, usually spring-controlled. In the present invention the ratchet and pawl mechanism has been incorporated to provide over-running to the final gear. The ratchet provides unidirectional rotation when it is attached to the final gear. The ratchet and pawl in the present invention enhances the free-wheel rotation due to re-engagement impact and would not affect the other parts. In the present invention a constant mesh gear arrangement is used which nullifies the impact of the re-engagement of the gears. Both gears of the manual charging and electrical charging mechanisms are in constant mesh with the main gear of the spring charging arrangement and they incorporate unidirectional clutches fitted inside the hub of the handle and the worm wheel. Hence when manual charging is done the electrical gear will slip due to unidirectional bearing. The present invention also comprises of the ratchet, which provides the overrunning to the system. A stationary pin is provided for disconnecting the coupling between ratchet and pawl when the springs are fully charged permitting the charging mechanism to overrun. A manual-charging handle is also provided in the system, which is connected to the gear mechanism. This can be coupled to the manual handle to operate the final gear. The system also comprises of worm gear driven by the worm. The worm gear is also coupled to another gear, which helps in driving the final gear. The overrunning mechanism also comprises of a pinion that is mounted on the main shaft of the motor. This pinion in combination with another pinion drives the worm. Thus the present invention comprises of a constant mesh gear system. The over-running mechanism comprises two separate driving points, one for manual charging and the other for electrical charging. This provides totally independent operation and there is freedom to select the desired gear ratio for manual or electrical operation without affecting each other. The over-running function is carried on maintaining large domain in the choice of gear ratios. Further it has now been 14 found that due to presence of toothless zone of sector gear it was not possible to have more than one gear in mesh and achieve overrunning function. This further constrained the choice of gear ratio for manual and /or electrical spring charging. Accordingly further improvement in overrunning has been achieved by excluding toothless zone in the sector gear. Thus the whole of the final gear in the present system is toothed and this achieves overrunning, as phase synchronization is not required and the gears never go out of mesh. This is illustrated in figure as well. The movement of "ON" push-button is locked by rotation of a spring-loaded pin. When the spring-loaded pin is in the popped out condition, the "ON" push button can be padlocked. From the given diagram it is noted that the spring-loaded pin is also provided with a cam profile. From the figure it is also clear that just beneath the push button there is a "L" shaped slider arrangement. The movement of the slide is initiated by the cam profile. This slide movement helps to jam the movement of the push button. So from outside further functioning of the button is stopped. For unlocking, the spring-loaded pin is to be pressed and rotated. From the figure it is observed that just below the cam profile there is a grooving. This grooving is provided to retain the cylinder in movement rotated and pressed position. The padlocking of the "OFF" push button in this case padlocks the manual spring charging handle. This padlocking mechanism prevents the handle movement and thus the MCCB in this case cannot be changed locally to the "OFF" state. Thus the spring-loaded pin is used to achieve padlocking unlike that in US 6192718 where the locking system is much complex. Further the system of the present invention is provided with stay put means in the OFF push button to ensure substantial charging of the spring. The stay put means enhances smooth charging of the spring during interruption of control supply to the motor by resuming charging on restoration of the power supply. US6153845 though teaches three selective modes of breaker actuation operation namely manual locked, manual unlocked and automatic for ON, OFF and TRIP operation of the breaker handle similar to the present system there is no stay put means. The stay put means ensures total spring charging even if the OFF push button is not kept actuated till the 15 springs are fully charged and also adapted so as to ensure that during spring charging operation if the control supply to motor is lost the spring resumes charging on restoration of power supply. When the OFF push button is pressed, it pushes the push button rod, which presses the "push-to-trip button". The window of the push button rod moves the operating lever of the toggle switch and closes it. The conical latching cam is provided with a spring-loaded slide located on the push button rod and is adapted to maintain the push button rod in pressed position in presence or absence of power supply till the spring is fully charged. On substantial charging of spring the flag fixed to the slider strikes the spring-loaded slide causing it to the release the latching cam. The spring present in push button rod causes the said rod and the push button to return to their initial positions. This means enhances total spring charging even if OFF push button is not kept actuated till springs are fully charged and are adapted to ensure that there is no loss of the energy so far supplied to the spring if anyhow the control power supply is lost. Thus even if during the spring charging operation the control supply to the motor is lost the spring resumes charging on restoration of supply. For facilitating maintenance of the MCCB as well as manual operation of the MCCB without using the motor operator a swivel arrangement adapted for retaining the mechanism in the completely swiveled out position is provided. It comprises a base plate bearing the motor operator mechanism; strut means; and locking means. The whole motor operator mechanism is mounted on the base plate which comprises a hinge assembly, permitting the mechanism to swivel out. To facilitate the mechanism to remain in the completely swiveled out position, a novel strut is provided. The strut holds the mechanism in the opened position, until it is released by pressing a lock head. The invention is now described by way of non-limiting illustrative drawings. 16 Brief description of accompanying drawings Figure 1 illustrates schematically the combination of features constituting the system for stored energy motor operation for circuit breaker in accordance with the present invention. Figure 2 illustrates in plan view the disposition of the motor and its operative connection to the crankshaft. Figure 3 is a plan view showing the slider- crank arrangement and arrangement for travel mismatch absorption. Figure 4 is a plan view illustrating the connection of operating shaft with respect to the crankshaft. Figure 5 is a plan view-illustrating crank in latched condition. Figure 6 illustrates an isometric view of the interconnection between the slider and the OFF push button. Figure 7 illustrates the disposition of the OFF push button, the switching means, stay put means as well as the latch for holding push button. Figure 8 illustrates the locking/padlocking of the ON push button. Figure 9 illustrates the locking/padlocking of the OFF push button. Figure 10 illustrates a plan view of the overrunning mechanism of the present invention. 17 Figure 11 illustrates an isometric view of the swiveling mechanism and the strut arrangement. Figure 12 illustrates manual charging operation means. Figures 13(A) and 13(B) illustrate the present and the prior art gearing systems. Figures 14(A) and (14B) illustrate the overrunning action by ratchet and pawl. As shown in Figure 1, the same illustrates an embodiment of the combination of features of the interior of motor operator in accordance with the invention as mounted on the MCCB. Reference is now invited to Figure 2, which illustrates the operative connection of the motor (201) with respect to the crankshaft (214) for the electrical operation of the system. As shown in said figure, a pinion (202) is mounted on the shaft of the motor, which drives a gear means (203). A worm (204) mounted on the axis of this gear (203) drives a worm wheel (205). On the axis of this worm wheel (205) is coupled another gear (206) which is driven through unidirectional clutch (207). This gear (206) is in turn adapted to drive a spur gear (208). This spur gear 208 drives a ratchet wheel (210), which drives the pawl (211). The pawl is pivoted on a pin (209), which is mounted operatively connected to the crankshaft (214). As further illustrated in Figure 3, the crank pin (216) is connected to a slider (233), which is restrained by plurality of springs (219). As the crank rotates, the spring (219) gets stretched and charges until the dead center is reached. Slightly beyond this point, as shown in figure 4, the motor is disconnected by a micro switch (220) actuated by a cam (221) mounted on the crankshaft (214) as further shown in Fig 4 and Fig. 5. As also shown in Fig 5 the crank (214) is adapted to be held by a latch (222). 18 To provide over running of the motor (201) after springs (219) are charged, the pawl (211) attached to the crankshaft (214) is lifted off the ratchet by a stationary pin (212), thereby mechanically disengaging the motor (201) from the crankshaft. When a closing command is given, the latch is released and the crank (214) is adapted to rotate by the energy stored in the springs (219), which in turn is adapted to bring the MCCB to ON position. For energizing the motor, the OFF push button (224) is required to be pressed which trips the MCCB and also switches on the motor (201) by means of a toggle switch (225) actuated by the said OFF push button. A stay put arrangement (Figure 6) is incorporated in the system to maintain the toggle switch (225) in the ON condition till the spring is substantially charged. At this stage, a rectangular shaped latch (226) holding the push button rod (227) and push button 224 is released. A micro switch (220) connected in parallel to the said toggle switch (225) and actuated by a cam (221) mounted on the said crankshaft (214) further disconnects the motor (201) when the springs (219) are completely charged. For automatic charging of the springs (219) after tripping MCCB (223) by means other than the local OFF push button (224) on the motor operator, trip alarm contact (not shown) being connected in parallel to the micro switch (220) after tripping of the system and is adapted to initiate automatic charging of the springs. In keeping with the other aspect, the system of the invention also provides for simple and easy to operate manual charging operation as further discussed hereunder in relation to accompanying Fig 12 For this mode of operation, handle 249 refer Fig 12, is adapted to be pulled out and rotated to and fro to charge the springs (219). This also is adapted to move the circuit breaker handle (218) to Reset/OFF position. In accordance with one aspect of the invention, an arresting means (250) is provided to ensure that the handle (249) cannot be rotated unless it is pulled out. For the purpose, a cavity (250) is mounted on the top of the enclosure (251), which holds the handle (249) is provided. This 19 arrangement clearly arrests the rotation of the handle (249) during motorized operation. The arrest of the handle movement by the cavity provides for a simple and cost-effective manner of controlling of the movement of the handle. To close the MCCB, the "ON" pushbutton (239) is pressed to delatch the crank (215) and discharge the closing springs (219). The ON pushbutton (239) (as shown in Fig 8) incorporates a profiled cam 240 adapted to convert axial push movement into rotary movement of the shaft (241)) and latch (222). This obviates the multiplicity of linkages to achieve rotary motion from an axial actuation. Figure 6 illustrates a stay put OFF push button (224) is connected to a push button rod (227) restrained by spring (228). A window (229) is located on the push button rod (227). The toggle switch (225) comprises of an operating lever (230) passing through the said window (229). Push button rod (227) comprises a conical latching cam (231) operatively coupled to spring loaded slide (226). With reference to figure 6 and 7, it is found that a flag (232) is fixed to the slider (233) operatively coupled to charging springs (219). The above stay put means in the system of the invention ensures total spring charging even if the OFF push button (224) is not kept actuated till the springs (219) are fully charged. It also ensures that during the spring charging operation, if the control supply to the motor (201) is lost, the springs (219) will resume charging on restoration of power supply. Further in accordance with other aspect the ON pushbutton (239) is provided with locking and padlocking arrangement as discussed hereunder in relation to Fig 8 The movement of ON pushbutton (239) is locked by pressing and rotation of a spring-loaded cylinder (234). When the cylinder (234) is in the popped out condition, the ON pushbutton (239) can be padlocked (235). The spring-loaded cylinder (234) is also provided with a cam profile (236), which causes a slide (237) to move and jam the movement of the pushbutton (239). For unlocking, the cylinder (234) is rotated. Similarly the OFF pushbutton (Fig 9) can be locked and padlocked. The padlocking of the OFF pushbutton (224) also padlocks the manual spring charging handle (249). This prevents the handle movement and thus the MCCB cannot be changed locally to OFF state. The MCCB of the invention is further adapted to be tripped by pressing "OFF" push button (124.) and the MCCB is brought to "Reset/Off" position, by moving the manual-charging handle (127) or through motorized operation as described above. The MCCB is brought to ON, Reset/OFF positions by the engagement of slider (233) of motor operator to the MCCB handle (218) as described above. The travel of the MCCB to these different positions can vary due to the tolerance on the components. A mismatch between the travel of the slider (233) of the operator and MCCB handle (218) can result into breakage of the MCCB handle or non-operation of the MCCB to the said ON or Reset/OFF positions. To take care of such problem in accordance with a further aspect of the invention the system includes an elastic coupling between the slider (233) and the MCCB handle (218) by a plurality of disc springs (238) to absorbs the said mismatch. Importantly in accordance with yet further aspect the system for stored energy motor operative circuit breaker of the invention is adapted to be swiveled out to access the MCCB handle to facilitate operation of the MCCB without the operator, as well as maintenance of the MCCB. In a stored energy motor operator, the motor charges the closing springs. When the spring charge is complete, the motor is switched off but however the motor is permitted to continue running after being mechanically disengaged from the charging mechanism. This is achieved by an overrunning mechanism. In figure 2 the crank 214 is driven by means of a ratchet 210 coupled to the final gear 217 of the charging mechanism through a pawl 211. When the springs are charged, an appropriately located stationary pin 212 lifts the pawl 211 and permits the charging mechanism to overrun. The final gear 217 can be driven by gear 208 coupled to manual charging handle 249. Alternately, the final gear 217 can also be driven by gear 206 coupled to worm gear 205, driven by worm 204, coupled to pinion 203, driven by pinion 202 mounted on the shaft of the motor 201. In figure 13(A), the final gear (217) is common for both manual and electrical charging mechanism and are mounted on the shaft (252). Any change in the number of teeth of gear (217) to achieve a different gear ratio will affect both manual and electrical charging ratios. In this invention, the gear ratios for manual and electrical spring charging are independent as illustrated in figure 13(B). In figures 14(A) and 14(B) the method of over-running with the help of the ratchet and the pawl arrangement is shown. In figure 14(B) the pawl engages with the ratchet during the charging process. Fig. 11 illustrates the strut means provided to enable the mechanism to remain in swiveled position to facilitate operation of the MCCB without the operator, as well as for maintenance of the MCCB. This comprises of a strut (246) pivoted on the base plate (253) by means of a hinge (245). The other end of the strut is coupled to strut lock head (247) through a pin (248). When the mechanism is completely swiveled about the hinge (244) , the strut lock head (247) gets locked into a profiled slot (254)on the bottom of the mechanism. The mechanism remains stable in this position until the strut lock head (247) is pressed. We claim 1. An overrunning mechanism adapted for a system for stored energy motor operation of moulded case circuit breakers, said over running mechanism comprising: operative connection of the motor with respect to an operating shaft comprising a pinion mounted on the shaft of the motor adapted to drive a gear means, a worm gear wheel mounted on the axis of said gear adapted to drive a worm gear wheel, a further gear coupled to said worm gear wheel driven through unidirectional clutch ,said further gear adapted to drive final gear and the operating shaft; being further adapted to be driven by a gear coupled to handle a crank mechanism driven by means of a ratchet coupled to the final gear of the charging mechanism through a pawl; such that when the springs are charged, an appropriately located stationary pin lifts the pawl and permits the charging mechanism to overrun; in operative connection with electrical operative means for selective change over of state of MCCB to ON, reset/OFF positions comprising a simple selective operative connection of the shaft of a motor to a gear system; crank operative slider means restrained by spring means wherein the rotation of crank is adapted for stretching of the spring and its charging, a cam means on the crank operatively connected to disconnect the motor by an operative switch means when the spring is stretched beyond a present dead center limit ,said slider means and the chargeable spring operatively connected to the circuit breaker handle for selective change over of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle and /or a manually operable handle means for selective change over of state of MCCB to ON, reset/OFF positions provided to charge a spring based operative slider means , said spring chargeable slider means operatively connected to the circuit breaker handle for selective change over of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle. 2. An overrunning mechanism as claimed in claim 1 wherein said final gear is adapted to be driven by manual charging handle or driven by the said pinion mounted on the shaft of motor for electrical charging. 3. An overrunning mechanism as claimed in claims 1 and 2 wherein separate driving points are present for the manual and electrical charging by means of separate gears. 4. An overrunning mechanism as claimed in claims 1 to 3 wherein the said separate gears are in constant mesh with the final gear. 5. An overrunning mechanism as claimed in claims 1 to 4 wherein the gear at the manual charging point and the gear at the electrical charging point incorporate unidirectional clutches fitted inside the hub of the handle and the worm wheel gear respectively such that when the manual charging is done the electrical gear slips due to its unidirectional bearing and vice versa. Dated this 18th day of October, 2004. DR. SANCHITA GANGULI of S. Majumdar& Co. (Applicant"s agent)

Full Text

FORM2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10; rule 13)

1. Title of the invention. -
2. Applicant

OVERRUNNING MECHANISM ADAPTED FOR A SYSTEM OF STORED ENERGY MOTOR OPERATION
(a) LARSEN & TOUBRO LIMITED
b) of L & T House, Ballard Estate, Mumbai - 400 001 State of Maharashtra, India
(c) An Indian Company

The following specification particularly describes the nature of this invention and the manner in which it is to be performed

The present application is divided out of Application No. 1032/MUM/2003 dated 03/10/2003.
Field of the Invention
The present invention relates to a system for stored energy motor operation for circuit breakers and in particular to a system for stored energy motor operation for moulded case circuit breakers (MCCB), which would be simple and cost-effective to obtain and safe and user friendly. More particularly the invention relates to system for stored energy motor operation being provided with a mechanism to prevent travel mismatch between the linear carriage and the operating handle by means of disc springs and provided with mechanism to prevent loss of the charging command so far supplied to the spring in the event the control power supply is lost. The system is further provided with overrunning mechanism with gear meshing. The system is also provided with freewheeling arrangement with ratchet and pawl. The system is further provided with an arrangement with stay put push button means. The system is further provided with a swivel arrangement and a strut means for retaining the mechanism in the completely swiveled out position.
Background Art
Moulded case circuit breakers (MCCB) usually have three stable operating positions namely "ON", "OFF" and "TRIPPED". In the ON condition, the contacts of the MCCB are closed and in the OFF position the contacts are open. The MCCB comes to the TRIPPED position in the event of an abnormal situation such as short circuit or an overload. It is also possible to even otherwise bring the MCCB to the TRIPPED position by operating a push button located on the MCCB identified as "Push- to-TRIP" button. The MCCB is further adapted for resetting from TRIPPED position to OFF position by moving its operating knob. Importantly, the above operations or

switch over from the various operating positions can be effected either manually or electrically with the help of motor operator, which is fixed to the MCCB.
In the presently available system, the MCCB is adapted for the above operative conditions/states by way of direct connection of the operating motor, geared to its operating knob. However, it is found that such systems required more operating time for the MCCB to actuate during change over from one state to the other.
US 6130392 teaches stored energy circuit breaker actuation apparatus for closing a circuit breaker assembly in a time period of circuit breaker operation between 50 and 100 milliseconds either through manual or electrical motor operation. It comprises housing of the circuit breaker, operator handle assembly, operator gear assembly, pinion gear assembly, stored energy charging and discharging assembly, energy storage assembly comprising springs that store energy when charged and release energy when discharged circuit breaker operating handle, series of gears for electric operation, an operative switch for the motor operator, a drive shaft, reduction gear assembly/gear mesh arrangement. It further provides for electronic control by means of silicon control rectifier and is provided with indicator means for indicating status of the stored energy.
An electric switch is used here. Generally, electric switches are robust in structural configuration and require high power for its own actuation. This results in the power loss of the total system and so the operation is not a cost effective one. The main charging operator gear has missing gear teeth in the order of about more than one-half of its circumference. Therefore during re-engagement of the gears phase synchronization is not maintained which gives rise to impact between the first tooth of the final gear and the worm gear arrangement. This may result in the damage of the gear arrangement. Further there is no mechanism to control the charging of spring to a definite level. Additionally the mechanism to prevent travel mismatch between the linear carriage and the operating handle comprise helical springs.

However such helical springs cannot be accommodated in a compact space for high force and hence high stroke/force ratio cannot be achieved.
US 6015959 teaches molded case electric power switches with cam driven, spring powered open and close mechanism: The system comprises energy storage spring, cam assembly, drive cam, latch mechanism, ratchet. The latch mechanism for control of storage of energy by the spring is further provided with Y-latch.
US6153845 teaches three selective modes of breaker actuation operation namely manual locked, manual unlocked and automatic for ON, OFF and TRIP operation of the breaker handle. For manual unlocked selection of local or remote operation is needed. If local is selected ON switch and OF switch of the stored energy assembly is used to turn ON or OFF the circuit breaker assembly while for remote the circuit breaker assembly cannot be turned ON or OFF. If manual locked operation is chosen it comprising selecting local or remote operation for which the stored energy assembly is not used to turn ON or OFF the circuit breaker assembly. For automatic operation further steps of selection of local or remote operation is needed. For local operation stored energy assembly is not used to turn ON the circuit breaker assembly and stored energy assembly is used to turn OFF the circuit breaker assembly. If remote operation is selected a remote ON button is used to cause stored energy assembly to turn on the circuit breaker assembly and OFF button is used to cause stored energy assembly to turn off the circuit breaker assembly. There is no mechanism to prevent loss of the energy so far supplied to the spring if anyhow the control power supply is lost.
US6166343 teaches unidirectional clutch assembly comprising unidirectional clutches to be used with an operator handle, pinion shaft assembly, worm gear assembly and pinion gear assembly of a stored energy assembly for use with a circuit breaker assembly. However there is no mechanism to absorb the impact due to re-engagement of the gears when the first unidirectional clutch means slips in one direction so that the operator handle does not move and the worm gear assembly rotates so as to rotate pinion gear assembly and when the second unidirectional

clutch means slips in one direction and the pinion gear assembly does not rotate so that the operator handle does not move. Here the main gear comprising the toothless zone and used for incremental gear operation, at the time of reengagement results in impact between the first gear tooth and the worm gear. There is no mesh gear arrangement in the clutch system.
US 6192718 teaches a stored energy assembly for use with a circuit breaker assembly such that the stored energy assembly is operable to locked and unlocked states. The mechanism for operating the stored energy assembly to locked and unlocked states comprises cylindrical key lock mounted on the stored energy assembly housing and at least a portion of the lock adapted to be moved to at least one unlocked and at least one locked position, a cylindrical lock arm, lifting member, locking hasp assembly. The system is complex.
US 6078017 teaches an adapter plate assembly for mounting stored energy assembly to a circuit breaker assembly comprising a mounting plate comprising a circuit breaker toggle aperture, a circuit breaker trip aperture, trip arm mounting aperture, trip arm comprising a trip flange. The mounting plate of the adapter assembly has a terminal bus assembly. This makes the system complex.
US 6072137 teaches a pinion gear carrier assembly for relating turning of an operator shaft by an operator handle to turning of a main operator gear for driving movement translation assembly to charge a stored energy assembly of a stored energy circuit breaker actuation apparatus. The pinion gear carrier assembly comprises a pinion gear carrier having an idler pinion gear-mounting member, driver pinion gear, an idler pinion gear mounted on the mounting member. The pinion gear carrier assembly operates a main operator gear such that the gear teeth span less than its full circumference. There is no mechanism for impact absorption between the gear and the idler, which may lead to damage of the operator gear and the idler. Moreover due to presence of toothless portion in the overrunning zone the motor is disengaged and after the spring is discharged the motor is re engaged. This leads to poor gear meshing between the gears and phase synchronization is required. A
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further drawback of toothless overrunning mechanism is interdependence of electrical and manual charging mechanism
US 6423917 teaches a motor operator for a circuit breaker. It teaches a mechanized system for manipulating an operating handle of a circuit interruption mechanism which comprises a motor drive assembly connected to mechanical linkage system which includes a recharging cam driven by the motor drive assembly for driving an energy storage system namely spring and an energy release mechanism to release the energy stored in the energy storage system. The recharging cam being coupled to drive plate and adapted to compress the spring to a predetermined value. A linear carriage coupled to the drive plate manipulates the operating handle of the circuit interruption mechanism when the spring is released from its compressed state. However there is no mechanism to prevent mismatch between the linear carriage and the operating handle, which may lead to breakage of the circuit breaker handle or no operation of the circuit breaker at the various positions.
US 6559743 teaches operating mechanism for a circuit breaker. It includes a holder assembly to receive a portion of the operating handle of the circuit breaker and is capable of movement between closed and open positions of the circuit breaker. There is drive plate coupled to the holder assembly and an energy storage mechanism for a plurality of states each with defined energy level and mechanical linkage system coupled to the energy storage mechanism and the drive plate. The mechanical linkage system responds to the motor drive assembly to disengage and reengage a set of circuit breaker contacts by moving operating handle. The energy storage mechanism comprising first and second springs of definite spring constant being positioned respectively in first fixture (with slots) and second fixture (of many members) and such that the two fixtures are operatively connected. The holder assembly comprising carriage, retaining bar rotatably mounted on carriage and spring. Thus the system is a complex with the incorporation of said holder assembly and there is no mechanism for countering travel mismatch.

Thus there is need to provide for a system for stored energy motor operation of moulded case circuit breakers which is simple, cost effective, provided with mechanism to prevent travel mismatch between the linear carriage and the operating handle yet having overrunning mechanism with gear meshing and provided with mechanism to prevent loss of the energy so far supplied to the spring if anyhow the control power supply is lost.
Objects of the Invention
Thus the basic object of the present invention is to provide a system of stored energy motor operation for circuit breakers especially moulded case circuit breakers with a mechanism to prevent travel mismatch between the linear carriage and the operating handle during breaker operation by means of disc springs of high force/stroke ratio with a fine tuning of threshold of its deflection providing a high elastic coupling limit.
Another object of the present invention is to provide a system of stored energy motor operation for circuit breaker especially moulded case circuit breaker, which would provide for fast and effective change over from various states of selective electrical and/or manual operation thereby effectively reducing the operating time of the MCCB.
Another object of the present invention is to provide a system of stored energy motor operation for circuit breaker such as moulded case circuit breakers adapted for electrical and/or manual operation which on one hand would effectively reduce the operating time of the MCCB and on the other hand would involve simple and cost-effective gadgets and thereby enable providing said system for stored energy motor operation for MCCB simple and easy to obtain and use.
Yet further object of the present invention is directed to provide for a system for stored energy motor operation for moulded case circuit breakers wherein the same is adapted for a simple yet effective electrical charging for generating the stored energy

for motor operation of the circuit breakers and would also have simple manual operative system for effective and advantageous use of the circuit breaker.
Yet another object of the present invention is to provide for a system for stored energy motor operation for moulded case circuit breakers which would achieve improved operating performance in terms of reduced operating time for change over to the various states of operation and would also involve simple and cost-effective gadgets and most importantly maintaining standard requirements of such stored energy operative circuit breakers for ready and wide scale use and application of the system.
Yet another object of the present invention is to provide for a system for stored energy motor operation for moulded case circuit breaker, which would ensure total spring charging thereby favoring complete and advantageous use of the stored energy in the operation of the device.
Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers which would take care of problems encountered when the MCCB is brought to ON, Reset/OFF positions by the engagement of the slider of motor operator to the MCCB handle during which the travel of MCCB to this different positions can vary due to the tolerance of the components.
Yet further object of the present invention is directed to provide for a system for stored energy motor operation for moulded case circuit breaker which would be adapted for automatic charging 0f spring after tripping of MCCB by means other than the local push OFF button on the motor operator.
Yet further object of the present invention is directed to provide for a system for stored energy motor operation for moulded case circuit breaker which would have simple and effective manual operations for the circuit breaker handle which would not only facilitate faster and effective change over of the operative state of the circuit
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breaker but would also ensure that the handle is maintained in the inoperative state during motorized operation of the circuit breaker.
Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers, which would have simple configuration, adapted to convert axial push movement of push buttons into rotary motion of shaft and latching means avoiding multiplicity of linkages.
Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers which would have standard requirement of locking of ON push buttons effectively in the locked and padlocked state and its unlocking for its operative function.
Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers which would effectively provide for the required locking and pad locking of the OFF push button whereby the handle as well as OFF pushbutton movement could be prevented and the MCCB cannot be made locally OFF.
Yet another object of the present invention is to provide for stored energy motor operation for moulded case circuit breakers wherein the stored energy motor operator would be adapted to access the MCCB handle to facilitate the operation of the MCCB even without the operator.
Yet another object of the present invention is to provide for stored energy motor operation for moulded case circuit breakers wherein the excess energy from the springs after closing the moulded case circuit breaker does not result in impact between the gears.
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A further object invention is to provide for stored energy motor-operation for moulded case circuit breaker, which overcomes the drawbacks of the conventional systems with regard to overrunning and adapted to use of multiple gear mesh.
Another object the present invention is to provide an over-running system with separate driving points for manual charging and electrical charging and hence totally independent operation.
Further one more object of the present invention there is provided a freewheeling arrangement for a system for stored energy motor operation of moulded case circuit breakers wherein the said freewheeling arrangement comprising ratchet and pawl arrangement adapted to absorb the excess energy in the spring resulting in an impact between the first tooth of the sector gear and the idler.
The other object of the present invention is directed to provide for a push button with an arrangement comprising stay put means ensuring that the spring will resume charging immediately on restoration of power supply, in case during the spring charging the control supply to the motor is lost.
Yet another object of the present invention is directed to provide for stored energy motor operation for moulded case circuit breakers with the mechanism assembly a hinge and a strut means for holding the mechanism in the fully opened state to facilitate maintenance.
Summary of the Invention
According to the basic aspect of the present invention there is provided an overrunning mechanism adapted for a system for stored energy motor operation of moulded case circuit breakers, said over running mechanism comprising: operative connection of the motor with respect to an operating shaft comprising a pinion mounted on the shaft of the motor adapted to drive a gear means, a worm
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gear wheel mounted on the axis of said gear adapted to drive a worm gear wheel, a further gear coupled to said worm gear wheel driven through unidirectional clutch .said further gear adapted to drive final gear and the operating shaft; being further adapted to be driven by a gear coupled to handle a crank mechanism driven by means of a ratchet coupled to the final gear of the charging mechanism through a pawl; such that when the springs are charged, an appropriately located stationary pin lifts the pawl and permits the charging mechanism to overrun; in operative connection with electrical operative means for selective change over of state of MCCB to ON, reset/OFF positions comprising a simple selective operative connection of the shaft of a motor to a gear system;
crank operative slider means restrained by spring means wherein the rotation of crank is adapted for stretching of the spring and its charging, a cam means on the crank operatively connected to disconnect the motor by an operative switch means when the spring is stretched beyond a present dead center limit ,said slider means and the chargeable spring operatively connected to the circuit breaker handle for selective change over of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle and /or a manually operable handle means for selective change over of state of MCCB to ON, reset/OFF positions provided to charge a spring based operative slider means , said spring chargeable slider means operatively connected to the circuit breaker handle for selective change over of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle.
Detailed Description Of The Invention
The above combination of electrical and/or manually operable stored energy motor operable system is directed to add to the desired flexibility in operation apart from fast and effective change over from various states of selective electrical and/or manual operation and thereby effectively reduce the operating time of the MCCB.
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The system of present invention for stored energy motor operation for circuit breakers especially moulded case circuit breakers would provide for much desired fast and effective change over from various states of selective electrical and/or manual operation and thereby effectively reduce the operating time of the MCCB and provide for absorbing the travel mismatch unlike most of the prior art systems where no such mechanism for absorbing the travel mismatch was present. A mismatch between the travel of the slider of the operator and MCCB handle can result into breakages of MCCB handle or non operation of MCCB to the said ON to OFF and vice versa positions. The present system uses elastic coupling by means of disc springs having high force/stroke ratio for which it can impart a very high force with respect to a minute displacement. On the other hand the helical spring used by US 6130392 could not be accommodated in a compact space for high force. Moreover the disc springs of the present invention further provide the coupling to be stiff yet compact unlike the prior art and also provide a high force/stroke ratio compared to the prior art. In contrast the present invention prevents the leakage in flux thereby making the breaker operation faster and yet absorbs the travel mismatch.
Unlike the helical springs, which are usually used for the purpose, the disc springs have characteristics of imparting a very high force for a small deflection i.e. the force/stroke ratio in the disc spring is very high. The system of the present invention includes a plurality of disc springs, which can be accommodated in a compact space, helping to attain a fine-tuning threshold of its deflection. This helps to absorb the breaker travel mismatch and thereby prevent breakage of the handle. The excess travel of the stored energy mechanism during the toggling operation is absorbed by the elastic coupling in the form of the disc springs incorporated in the charging arrangement. The requirement of the elastic coupling is not to deflect from its initial position until the operating forces of the handle has exceeded and necessarily deflect before the breaking force of the handle is attained for which a stiff and compact coupling is required. This is easier to achieve in disc spring than the conventional helical spring.
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Importantly, the above system on one hand would effectively reduce the operating time of the MCCB and on the other hand would involve simple and cost-effective gadgets and thereby enable providing said system for stored energy motor operation for MCCB simple and easy to obtain and use.
An improved spring charging arrangement for a stored energy motor operator incorporated in moulded case circuit breaker system having a spring of definite dimensional configuration and a particular spring constant. This spring constant depends on the nature of the material used in the spring and its dimension.
A plate of rectangular dimension called the slider is fixed to the spring. A crank pin is connected to slider. As the crank rotates the spring gets stretched and charges until the dead center is reached. Slightly beyond dead center if the spring is stretched, the motor is disconnected by a micro switch, which is actuated by a cam profile on the crankshaft.
The stored spring potential energy can be used or transformed into mechanical energy, which may be utilized in the formation of the rotational inertia and finally the rotational torque. This rotational torque gives the moment of force to rotate the crank, which finally helps to achieve the initial operation or the toggling operation.
From the plan view of the interior of the motor operator it is realizable that the conversion of mechanical energy to potential energy is incorporated by respective gearing arrangements.
Even if the control supply to the motor is deactivated by some means the electrical energy till then supplied is not lost but it is stored in the form of spring potential energy. Again, on restoration of the power supply the spring resumes charging. Therefore, the storing of energy in the spring can be controlled to any limitations by an arrangement of crank gears coupled the spring through the slider arrangement.
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As the crank rotates, the spring is stretched and thus there is gain in the spring potential energy. This energy can be kept to any value by disengaging the motor from the slider arrangement thus stopping the spring to stretch any further. The crank attached to this spring via the slider is provided with a micro switch actuated by a cam coupled to the crankshaft. When a charging/reset command is given, the rotation of the crank is stopped by a latch, which locks the crank at particular position. A suitably cam shaped profile is provided on the crank, which holds the crank against the latch.
Now the energy so far stored in the spring is used to rotate the crank and perform the required operation of the motor operator.
The elastic coupling between the slider and the breaker handle comprises disc springs. The disc springs are accommodated in a compact space fixed to the slider and the breaker handle, which would be troublesome if instead helical springs are used. Since the volumetric configuration of the disc spring is less than that of the helical one, so there is a reduction in the total volume of the circuit breaker case. Therefore the mass of the material used for casing is less thus reducing the cost. The most important characteristic of the disc spring is high force/stroke ratio to impart high force for a very small displacement from its initial position.
This arrangement enables to absorb the travel mismatch of the motor operator and MCCB handle an elastic coupling is done in between the slider and the molded case circuit breaker by a plurality of disc spring to absorb the said mismatch. The sensitivity of the disc spring may also be considered keeping in mind the high force/stroke ratio. Due to it"s high sensitivity a fine tuning of the threshold of it"s deflection would impart a greater force on the disc spring thus raising the elastic coupling limit which compensate for the above travel mismatch.
An overrunning mechanism is provided in combination with the charging mechanism for a stored energy motor operator. The crank is driven by means of a pawl. The
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pawl is coupled to the final gear of the charging mechanism through a ratchet, which is a pivoted catch, usually spring-controlled. In the present invention the ratchet and pawl mechanism has been incorporated to provide over-running to the final gear. The ratchet provides unidirectional rotation when it is attached to the final gear. The ratchet and pawl in the present invention enhances the free-wheel rotation due to re-engagement impact and would not affect the other parts. In the present invention a constant mesh gear arrangement is used which nullifies the impact of the re-engagement of the gears.
Both gears of the manual charging and electrical charging mechanisms are in constant mesh with the main gear of the spring charging arrangement and they incorporate unidirectional clutches fitted inside the hub of the handle and the worm wheel. Hence when manual charging is done the electrical gear will slip due to unidirectional bearing. The present invention also comprises of the ratchet, which provides the overrunning to the system. A stationary pin is provided for disconnecting the coupling between ratchet and pawl when the springs are fully charged permitting the charging mechanism to overrun.
A manual-charging handle is also provided in the system, which is connected to the gear mechanism. This can be coupled to the manual handle to operate the final gear. The system also comprises of worm gear driven by the worm. The worm gear is also coupled to another gear, which helps in driving the final gear.
The overrunning mechanism also comprises of a pinion that is mounted on the main shaft of the motor. This pinion in combination with another pinion drives the worm. Thus the present invention comprises of a constant mesh gear system.
The over-running mechanism comprises two separate driving points, one for manual charging and the other for electrical charging. This provides totally independent operation and there is freedom to select the desired gear ratio for manual or electrical operation without affecting each other. The over-running function is carried on maintaining large domain in the choice of gear ratios. Further it has now been
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found that due to presence of toothless zone of sector gear it was not possible to have more than one gear in mesh and achieve overrunning function. This further constrained the choice of gear ratio for manual and /or electrical spring charging. Accordingly further improvement in overrunning has been achieved by excluding toothless zone in the sector gear. Thus the whole of the final gear in the present system is toothed and this achieves overrunning, as phase synchronization is not required and the gears never go out of mesh. This is illustrated in figure as well.
The movement of "ON" push-button is locked by rotation of a spring-loaded pin. When the spring-loaded pin is in the popped out condition, the "ON" push button can be padlocked. From the given diagram it is noted that the spring-loaded pin is also provided with a cam profile. From the figure it is also clear that just beneath the push button there is a "L" shaped slider arrangement. The movement of the slide is initiated by the cam profile. This slide movement helps to jam the movement of the push button. So from outside further functioning of the button is stopped. For unlocking, the spring-loaded pin is to be pressed and rotated. From the figure it is observed that just below the cam profile there is a grooving. This grooving is provided to retain the cylinder in movement rotated and pressed position. The padlocking of the "OFF" push button in this case padlocks the manual spring charging handle. This padlocking mechanism prevents the handle movement and thus the MCCB in this case cannot be changed locally to the "OFF" state. Thus the spring-loaded pin is used to achieve padlocking unlike that in US 6192718 where the locking system is much complex.
Further the system of the present invention is provided with stay put means in the OFF push button to ensure substantial charging of the spring. The stay put means enhances smooth charging of the spring during interruption of control supply to the motor by resuming charging on restoration of the power supply. US6153845 though teaches three selective modes of breaker actuation operation namely manual locked, manual unlocked and automatic for ON, OFF and TRIP operation of the breaker handle similar to the present system there is no stay put means. The stay put means ensures total spring charging even if the OFF push button is not kept actuated till the
15

springs are fully charged and also adapted so as to ensure that during spring charging operation if the control supply to motor is lost the spring resumes charging on restoration of power supply. When the OFF push button is pressed, it pushes the push button rod, which presses the "push-to-trip button". The window of the push button rod moves the operating lever of the toggle switch and closes it. The conical latching cam is provided with a spring-loaded slide located on the push button rod and is adapted to maintain the push button rod in pressed position in presence or absence of power supply till the spring is fully charged. On substantial charging of spring the flag fixed to the slider strikes the spring-loaded slide causing it to the release the latching cam. The spring present in push button rod causes the said rod and the push button to return to their initial positions. This means enhances total spring charging even if OFF push button is not kept actuated till springs are fully charged and are adapted to ensure that there is no loss of the energy so far supplied to the spring if anyhow the control power supply is lost. Thus even if during the spring charging operation the control supply to the motor is lost the spring resumes charging on restoration of supply.
For facilitating maintenance of the MCCB as well as manual operation of the MCCB without using the motor operator a swivel arrangement adapted for retaining the mechanism in the completely swiveled out position is provided. It comprises a base plate bearing the motor operator mechanism; strut means; and locking means. The whole motor operator mechanism is mounted on the base plate which comprises a hinge assembly, permitting the mechanism to swivel out. To facilitate the mechanism to remain in the completely swiveled out position, a novel strut is provided. The strut holds the mechanism in the opened position, until it is released by pressing a lock head. The invention is now described by way of non-limiting illustrative drawings.
16

Brief description of accompanying drawings
Figure 1 illustrates schematically the combination of features constituting the system for stored energy motor operation for circuit breaker in accordance with the present invention.
Figure 2 illustrates in plan view the disposition of the motor and its operative connection to the crankshaft.
Figure 3 is a plan view showing the slider- crank arrangement and arrangement for travel mismatch absorption.
Figure 4 is a plan view illustrating the connection of operating shaft with respect to the crankshaft.
Figure 5 is a plan view-illustrating crank in latched condition.
Figure 6 illustrates an isometric view of the interconnection between the slider and the OFF push button.
Figure 7 illustrates the disposition of the OFF push button, the switching means, stay put means as well as the latch for holding push button.
Figure 8 illustrates the locking/padlocking of the ON push button.
Figure 9 illustrates the locking/padlocking of the OFF push button.
Figure 10 illustrates a plan view of the overrunning mechanism of the present invention.
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Figure 11 illustrates an isometric view of the swiveling mechanism and the strut arrangement.
Figure 12 illustrates manual charging operation means.
Figures 13(A) and 13(B) illustrate the present and the prior art gearing systems.
Figures 14(A) and (14B) illustrate the overrunning action by ratchet and pawl.
As shown in Figure 1, the same illustrates an embodiment of the combination of features of the interior of motor operator in accordance with the invention as mounted on the MCCB.
Reference is now invited to Figure 2, which illustrates the operative connection of the motor (201) with respect to the crankshaft (214) for the electrical operation of the system. As shown in said figure, a pinion (202) is mounted on the shaft of the motor, which drives a gear means (203). A worm (204) mounted on the axis of this gear (203) drives a worm wheel (205). On the axis of this worm wheel (205) is coupled another gear (206) which is driven through unidirectional clutch (207). This gear (206) is in turn adapted to drive a spur gear (208). This spur gear 208 drives a ratchet wheel (210), which drives the pawl (211). The pawl is pivoted on a pin (209), which is mounted operatively connected to the crankshaft (214). As further illustrated in Figure 3, the crank pin (216) is connected to a slider (233), which is restrained by plurality of springs (219).
As the crank rotates, the spring (219) gets stretched and charges until the dead center is reached.
Slightly beyond this point, as shown in figure 4, the motor is disconnected by a micro switch (220) actuated by a cam (221) mounted on the crankshaft (214) as further shown in Fig 4 and Fig. 5. As also shown in Fig 5 the crank (214) is adapted to be held by a latch (222).
18

To provide over running of the motor (201) after springs (219) are charged, the pawl (211) attached to the crankshaft (214) is lifted off the ratchet by a stationary pin (212), thereby mechanically disengaging the motor (201) from the crankshaft. When a closing command is given, the latch is released and the crank (214) is adapted to rotate by the energy stored in the springs (219), which in turn is adapted to bring the MCCB to ON position.
For energizing the motor, the OFF push button (224) is required to be pressed which trips the MCCB and also switches on the motor (201) by means of a toggle switch (225) actuated by the said OFF push button. A stay put arrangement (Figure 6) is incorporated in the system to maintain the toggle switch (225) in the ON condition till the spring is substantially charged. At this stage, a rectangular shaped latch (226) holding the push button rod (227) and push button 224 is released. A micro switch
(220) connected in parallel to the said toggle switch (225) and actuated by a cam
(221) mounted on the said crankshaft (214) further disconnects the motor (201) when the springs (219) are completely charged.
For automatic charging of the springs (219) after tripping MCCB (223) by means other than the local OFF push button (224) on the motor operator, trip alarm contact (not shown) being connected in parallel to the micro switch (220) after tripping of the system and is adapted to initiate automatic charging of the springs.
In keeping with the other aspect, the system of the invention also provides for simple and easy to operate manual charging operation as further discussed hereunder in relation to accompanying Fig 12
For this mode of operation, handle 249 refer Fig 12, is adapted to be pulled out and rotated to and fro to charge the springs (219). This also is adapted to move the circuit breaker handle (218) to Reset/OFF position. In accordance with one aspect of the invention, an arresting means (250) is provided to ensure that the handle (249) cannot be rotated unless it is pulled out. For the purpose, a cavity (250) is mounted on the top of the enclosure (251), which holds the handle (249) is provided. This
19

arrangement clearly arrests the rotation of the handle (249) during motorized operation. The arrest of the handle movement by the cavity provides for a simple and cost-effective manner of controlling of the movement of the handle.
To close the MCCB, the "ON" pushbutton (239) is pressed to delatch the crank (215) and discharge the closing springs (219).
The ON pushbutton (239) (as shown in Fig 8) incorporates a profiled cam 240 adapted to convert axial push movement into rotary movement of the shaft (241)) and latch (222). This obviates the multiplicity of linkages to achieve rotary motion from an axial actuation.
Figure 6 illustrates a stay put OFF push button (224) is connected to a push button rod (227) restrained by spring (228). A window (229) is located on the push button rod (227). The toggle switch (225) comprises of an operating lever (230) passing through the said window (229). Push button rod (227) comprises a conical latching cam (231) operatively coupled to spring loaded slide (226).
With reference to figure 6 and 7, it is found that a flag (232) is fixed to the slider (233) operatively coupled to charging springs (219).
The above stay put means in the system of the invention ensures total spring charging even if the OFF push button (224) is not kept actuated till the springs (219) are fully charged. It also ensures that during the spring charging operation, if the control supply to the motor (201) is lost, the springs (219) will resume charging on restoration of power supply.
Further in accordance with other aspect the ON pushbutton (239) is provided with locking and padlocking arrangement as discussed hereunder in relation to Fig 8
The movement of ON pushbutton (239) is locked by pressing and rotation of a spring-loaded cylinder (234). When the cylinder (234) is in the popped out condition,

the ON pushbutton (239) can be padlocked (235). The spring-loaded cylinder (234) is also provided with a cam profile (236), which causes a slide (237) to move and jam the movement of the pushbutton (239).
For unlocking, the cylinder (234) is rotated.
Similarly the OFF pushbutton (Fig 9) can be locked and padlocked. The padlocking of the OFF pushbutton (224) also padlocks the manual spring charging handle (249). This prevents the handle movement and thus the MCCB cannot be changed locally to OFF state.
The MCCB of the invention is further adapted to be tripped by pressing "OFF" push button (124.) and the MCCB is brought to "Reset/Off" position, by moving the manual-charging handle (127) or through motorized operation as described above.
The MCCB is brought to ON, Reset/OFF positions by the engagement of slider (233) of motor operator to the MCCB handle (218) as described above. The travel of the MCCB to these different positions can vary due to the tolerance on the components. A mismatch between the travel of the slider (233) of the operator and MCCB handle (218) can result into breakage of the MCCB handle or non-operation of the MCCB to the said ON or Reset/OFF positions. To take care of such problem in accordance with a further aspect of the invention the system includes an elastic coupling between the slider (233) and the MCCB handle (218) by a plurality of disc springs (238) to absorbs the said mismatch.
Importantly in accordance with yet further aspect the system for stored energy motor operative circuit breaker of the invention is adapted to be swiveled out to access the MCCB handle to facilitate operation of the MCCB without the operator, as well as maintenance of the MCCB.
In a stored energy motor operator, the motor charges the closing springs. When the spring charge is complete, the motor is switched off but however the motor is

permitted to continue running after being mechanically disengaged from the charging mechanism. This is achieved by an overrunning mechanism.
In figure 2 the crank 214 is driven by means of a ratchet 210 coupled to the final gear 217 of the charging mechanism through a pawl 211. When the springs are charged, an appropriately located stationary pin 212 lifts the pawl 211 and permits the charging mechanism to overrun. The final gear 217 can be driven by gear 208 coupled to manual charging handle 249. Alternately, the final gear 217 can also be driven by gear 206 coupled to worm gear 205, driven by worm 204, coupled to pinion 203, driven by pinion 202 mounted on the shaft of the motor 201.
In figure 13(A), the final gear (217) is common for both manual and electrical charging mechanism and are mounted on the shaft (252). Any change in the number of teeth of gear (217) to achieve a different gear ratio will affect both manual and electrical charging ratios.
In this invention, the gear ratios for manual and electrical spring charging are independent as illustrated in figure 13(B).
In figures 14(A) and 14(B) the method of over-running with the help of the ratchet and the pawl arrangement is shown. In figure 14(B) the pawl engages with the ratchet during the charging process.
Fig. 11 illustrates the strut means provided to enable the mechanism to remain in swiveled position to facilitate operation of the MCCB without the operator, as well as for maintenance of the MCCB.
This comprises of a strut (246) pivoted on the base plate (253) by means of a hinge (245). The other end of the strut is coupled to strut lock head (247) through a pin (248). When the mechanism is completely swiveled about the hinge (244) , the strut lock head (247) gets locked into a profiled slot (254)on the bottom of the mechanism. The mechanism remains stable in this position until the strut lock head (247) is pressed.

We claim
1. An overrunning mechanism adapted for a system for stored energy motor operation of moulded case circuit breakers, said over running mechanism comprising:
operative connection of the motor with respect to an operating shaft comprising a pinion mounted on the shaft of the motor adapted to drive a gear means, a worm gear wheel mounted on the axis of said gear adapted to drive a worm gear wheel, a further gear coupled to said worm gear wheel driven through unidirectional clutch ,said further gear adapted to drive final gear and the operating shaft; being further adapted to be driven by a gear coupled to handle a crank mechanism driven by means of a ratchet coupled to the final gear of the charging mechanism through a pawl; such that when the springs are charged, an appropriately located stationary pin lifts the pawl and permits the charging mechanism to overrun;
in operative connection with electrical operative means for selective change over of state of MCCB to ON, reset/OFF positions comprising a simple selective operative connection of the shaft of a motor to a gear system; crank operative slider means restrained by spring means wherein the rotation of crank is adapted for stretching of the spring and its charging, a cam means on the crank operatively connected to disconnect the motor by an operative switch means when the spring is stretched beyond a present dead center limit ,said slider means and the chargeable spring operatively connected to the circuit breaker handle for selective change over of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle and /or a manually operable handle means for selective change over of state of MCCB to ON, reset/OFF positions provided to charge a spring based operative slider means , said spring chargeable slider means operatively connected to the circuit breaker handle for selective change over

of state of MCCB to ON, reset/OFF positions by selective operative contact of said slider to the MCCB handle.
2. An overrunning mechanism as claimed in claim 1 wherein said final gear is adapted to be driven by manual charging handle or driven by the said pinion mounted on the shaft of motor for electrical charging.
3. An overrunning mechanism as claimed in claims 1 and 2 wherein separate driving points are present for the manual and electrical charging by means of separate gears.
4. An overrunning mechanism as claimed in claims 1 to 3 wherein the said separate gears are in constant mesh with the final gear.
5. An overrunning mechanism as claimed in claims 1 to 4 wherein the gear at the manual charging point and the gear at the electrical charging point incorporate unidirectional clutches fitted inside the hub of the handle and the worm wheel gear respectively such that when the manual charging is done the electrical gear slips due to its unidirectional bearing and vice versa.
Dated this 18th day of October, 2004.
DR. SANCHITA GANGULI
of S. Majumdar& Co.
(Applicant"s agent)

Documents:

1126-mum-2004-abstract.doc

1126-mum-2004-abstract.pdf

1126-mum-2004-claims.doc

1126-mum-2004-claims.pdf

1126-mum-2004-correspondence.pdf

1126-mum-2004-correspondence[ipo].pdf

1126-mum-2004-description(granted).doc

1126-mum-2004-description[granted].pdf

1126-mum-2004-drawing.pdf

1126-mum-2004-form 1.pdf

1126-mum-2004-form 18.pdf

1126-mum-2004-form 2(granted).doc

1126-mum-2004-form 2[granted].pdf

1126-mum-2004-form 2[title page].pdf

1126-mum-2004-form 3.pdf

1126-mum-2004-power of attorney.pdf

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Patent Number

212325

Indian Patent Application Number

1126/MUM/2004

PG Journal Number

04/2008

Publication Date

25-Jan-2008

Grant Date

30-Nov-2007

Date of Filing

20-Oct-2004

Name of Patentee

LARSEN & TOUBRO LIMITED

Applicant Address

L & T HOUSE, BALLARD ESTATE, MUMBAI-400 001,

Inventors:

#	Inventor's Name	Inventor's Address
1	JAGANNATH ALLADI	LARSEN & TOUBRO LIMITED; PSW/SDP, ELECTRICAL BUSINESS GROUP, POWAI WORKS(EAST), SAKI VIHAR ROAD, MUMBAI--400 072,
2	SHAH BHAGAVATILAL RAJESH	LARSEN & TOUBRO LIMITED; PSW/SDP, ELECTRICAL BUSINESS GROUP, POWAI WORKS(EAST), SAKI VIHAR ROAD, MUMBAI--400 072,
3	CHOUDHARI GIRIDHAR SADANAND	LARSEN & TOUBRO LIMITED; PSW/SDP, ELECTRICAL BUSINESS GROUP, POWAI WORKS(EAST), SAKI VIHAR ROAD, MUMBAI--400 072,

PCT International Classification Number

H01H71/10 H01H71/70 H01H3/30

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA