F0RM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: AN IMPROVED STORED ENERGY MOTOR
OPERATING MECHANISM FOR SWITCHING DEVICES
2. Applicant(s):
(a) NAME: LARSEN & TOUBRO LIMITED
(b) NATIONALITY: An Indian Company.
(c) ADDRESS: L & T House, Ballard Estate, Mumbai 400 001,
State of Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention relates to an improved stored energy motor operating mechanism for switching devices. More particularly, the invention is concerned about minimizing the amount of stored energy required for operating switching devices. The mechanism of the invention is provided with a unique rack and pinion arrangement operatively engaged and interconnected with Cam-Latch arrangement.
BACKGROUND OF THE INVENTION
Use of electrical devices is well known for making, breaking and to provide safety in a typical electrical distribution system. These devices get mounted inside a board or panel board for added safety to the operator. Most often these devices are required to be operated either from outside or by opening the enclosure/ panel. In view of operator's safety, remote operation is an alternative way to operate the switching devices. Usually to achieve this, an add-on accessory is mounted over the switching device, which may operate the device when called for.
Also in today's scenario response time for an electrical switching system to switchover from one desired source to the other is gaining importance. Thus with a view of lesser operational time and remote operation of a switching device, stored energy type of motor mechanism are used.
In current scenario, one of the inventions uses portion of stored energy to close the circuit breaker. Thus, energy is wasted in overcoming resistance introduced by components used in charging systems. Further, if the charging system is manually operated, it can be interrupted or overrun when the charging system is engaged during manual operation of manual charging system. Yet in another scenario, some of inventions use two springs of different stiffness for charging and discharging mechanism in motor operating system for circuit breaker switching operation.

US 6130392 disclose a stored energy circuit breaker operator for association with an operating handle of a circuit breaker contains springs that store energy when charged and that release energy when discharged. Energy is stored when a movement translation assembly is moved in a charging direction by an operator gear, and stored energy is released when a release apparatus releases the operator gear, causing the movement translation assembly to move in a discharging direction. The circuit breaker operating handle is moved to ON position by the charging movement of the movement translation assembly, and as stored energy is released, the discharging movement of the movement translation assembly moves the operating handle to OFF position. The operator gear is operated via an operator handle, operator shaft, and pinion gear assembly. The pinion gear assembly has a carrier pivotally associated with the operator shaft and a pinion gear that rotates the operator gear. The operator gear may also be turned by an electric motor and series of gears to accomplish electric operation of the circuit breaker.
US 6,166,343 discloses a unidirectional clutch assembly for use with an operator handle, pinion shaft assembly, a worm gear assembly and a pinion gear assembly of a stored energy assembly for use with a circuit breaker assembly, the operator handle and pinion shaft assembly including an operator handle having an outer handle hub having a first recess for receiving a first end of the pinion shaft assembly, the worm gear assembly fitting over the pinion shaft assembly and the pinion shaft assembly having a second end for receiving a pinion gear assembly, the unidirectional clutch assembly comprising a first unidirectional clutch structure, wherein the first unidirectional clutch structure fits over the first end of the pinion shaft and the unidirectional clutch structure is fitted into the first recess of the outer handle hub; and a second unidirectional clutch structure, wherein the second unidirectional clutch structure fits within the worm gear assembly and over the pinion shaft assembly between the first and second ends of the pinion shaft assembly, wherein the first unidirectional clutch structure and said second

unidirectional clutch structure are oriented in the same direction so that they slip unidirectionally in the same direction.
US 6,192,718 discloses a key lock and locking hasp assembly for a stored energy circuit breaker operator assembly. It is provided with an electrical control module for use with a stored energy circuit breaker assembly having a motor for use with a circuit breaker assembly, the circuit breaker assembly providing an electrical signal through electrical contacts for actuating the circuit breaker assembly, the electrical control module comprising: a rectifying circuit, which receives and rectifies said electrical signal so as to provide a rectified electrical signal; a motor switch circuit connected to the motor: and an electrical signal flow maintenance circuit, which is operatively connected to said rectifying circuit, said motor switch circuit and the motor, wherein said electrical signal flow circuit maintenance maintains at least a threshold rectified electrical when the electrical contacts are closed so that said motor switch circuit is on and the motor operates.
US 4042896 discloses a manual and motor operated circuit breaker. It is provided with a circuit function which is adapted for either manual or motor driven operation, as desired. Motor driven operation is achieved by the incorporation of a power unit comprising a motor selectively drivingly coupled to the circuit breaker operating mechanism and operating to charge the mechanism spring incident to closing the breaker contacts. Upon completion of a charging function, a closing solenoid is energized to effect release of the stored energy, which powers the breaker contacts to their closed position. Control elements sensitive to the condition of the operating mechanism and the position of the breaker movable contacts function to appropriately condition switching logic in the motor and closing solenoid circuit for sequencing the charging and closing functions in a reliable manner. The control elements further function to selectively position indicator means effective to visually identify the various breaker conditions.
US 6130392, discloses a stored energy circuit breaker operator , which is based on scotch yoke mechanism to convert the rotary motion to a linear motion.

Prior art is established around the concept of a cam pushing a hinged plate in-turn driving the knob of the switching device. In such a case the motion gets transmitted through the physical displacement by virtue of friction. Also the motion is purely unidirectional. In all the mechanism concepts till date the basic rotary motion that gets translated to rotary motion is unidirectional. So while the toggle movement is linear to and fro, the mechanism arrangement translates the unidirectional movement to a linear to and fro arrangement. In the present invention, the conversion of the rotary to linear happens by a rack and pinion arrangement. Because of this gearing scheme (rack and pinion) the losses in terms of friction is very less and hence the overall mechanical output from the mechanism increases.
Thus, there is a need to overcome the disadvantages of the prior art. Therefore, the purpose of the present invention is stored energy motor operating mechanism which would be able to operate switching devices with minimum amount of losses in energy transmission therein. Also, there is a need for mounting the stored energy motor operating mechanism on the circuit breaker such that the knob holder of the motor operating mechanism engages positively with the operating knob of the circuit breaker.
The inventors of the present invention have found that switching devices can be operated with lesser amount of energy by means of an operating mechanism comprising a unique rack and pinion arrangement operatively engaged and interconnected with Cam-Latch-catch arrangement. This would also facilitate less number of components in a stored energy motor operating mechanism for circuit breaker operation.
OBJECTS OF THE INVENTION
An object of the present invention is to overcome the problems/disadvantages of the prior art.

Another object of the present invention is to provide a stored energy motor operating mechanism for switching devices.
Another object of the present invention is to provide cam-latch-catch arrangement for facilitating uni-direction rotation in conjunction with a rack and pinion mechanism.
Yet another object of the present invention is to provide pawl and ratchet arrangement along with cam-latch-catch arrangement for facilitating driving of knob of switching device.
Further object of the present invention is to provide a synchronized double de-latching arrangement for facilitating safety of switching device.
Yet, another object of the present invention is to provide an improved mechanism, which is operated either through manual or automatic operation.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided an improved stored energy motor operating mechanism for switching devices, said mechanism comprising:
base means adapted to be mounted on the switching device;
core operating mechanism comprising: motor means, gear system, shaft means, rack and pinion arrangement; plurality of solenoid means, spring means; catch-latch-cam arrangement; pawl-ratchet arrangement;
wherein said catch-latch-cam arrangement work in concurrence with said pawl-ratchet arrangement during charging and discharging of said spring means; wherein said motor means being operatively connected to said gear system so as to rotate said shaft means whereby rotation of said shaft means unidirectionally

being controlled by said catch-latch-cam arrangement; said gear system being operatively connected to said rack and pinion arrangement such that said rack means moves in a substantial linear direction thereby actuating knob of a conventional switching device during charging;
wherein one of said plurality of solenoids pushes said catch-latch-cam arrangement during discharging operation thereby attaining de-latching position and wherein another solenoid of said plurality of solenoids pushes pawl-ratchet arrangement attaining further de-latching position such that said shaft means rotates freely such that said spring means pulls said rack means thereby actuating the switching device.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig 1 illustrates an isometric view of the stored energy mechanism of the present invention placed on top of the switching devices.
Fig 2 illustrates an isometric view of the stored energy mechanism of the present invention with the housing removed particularly, showing the motor and gear system.
Fig 3 illustrates the front view of stored energy mechanism on RHS plate
Fig 4 illustrates the front view of stored energy mechanism on LHS plate
Fig 5 illustrates an isometric view of the stored energy mechanism showing the gear system of the present invention placed on top of the switching devices.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
According to the invention there is provided a stored energy motor operating mechanism for switching device operations. The various embodiments of the present invention provides a stored energy motor operating mechanism for circuit

breaker operation, to drive the circuit breaker to one of ON, OFF or RESET state externally or remotely.
According to one embodiment of the present invention, the mechanism consists of a motor (1) which is a primary mover. This rotary motion is bidirectional, so it aids to higher mechanical efficiency. This rotational energy generated by motor then transmitted to a drive shaft through a gear mechanism which basically reduces RPM and increases torque. The rotary motion is converted to a linear motion by a rack and pinion mechanism. A rack (knob driver/knob holder 14) and pinion mechanism is provided in order to drive the knob between states (ON, TRIP, OFF) The stored energy operator and the switching device are engaged through a rack (14) thus the movement of Rack (14) causes the switching on and off operations of the device.
With reference to figure 1, the apparatus is fixed on top of the switching device (31) by means of four screws. The controlling of knob (30) of switching device is taken care by central portion of the operator. The operator majorly comprises three sub assemblies namely Base (21), Core mechanism and Top cover (not shown in figure).
The function of base assembly (21) is to take care of most of the electrical systems. It channelizes incoming power supply through logic circuit to various electrical components which includes safety devices as well. Recesses are provided on base to facilitate wire routing as it keeps away from the moving components of the mechanism.
A core mechanism is built on two side plates, which are RHS (12) and LHS (16) plates. Between these plates there is a main driving mechanism and a charging spring (25) is arranged. RHS plate consists of a gear train and handle assembly for manual charging as shown in figure 3. A pawl (22) and ratchet (7) with a RHS solenoid (23) is mounted on this plate. RHS plate also guides the trip lever (15). LHS plate holds the catch-latch-cam (17, 18, and 19) arrangement on the outer side and a LHS solenoid (28), as shown in figure 4, for operating a catch on the

inner side. Both the plates are fixed together by means of four pins screwed with them. Main shaft (27) is rested on these plates through rollers as shown in figure 4.
As shown in figure 2, Core mechanism has a motor arranged on the RHS plate in the operator. A gearing system is connected to the motor (1). A knob driving mechanism is mounted between side plates in the Operator. A knob holder (14) is attached to the knob driving mechanism. A knob holder pin (26) is provided in the knob holder. A charging spring means (25) is connected to the knob driving mechanism and to the pin (13) fixing the side plates in position. To accommodate the variations of knob travel, a pin & compression spring assembly is used in conjunction with knob driver. A solenoid (28) mounted on the inner portion of LHS in the circuit breaker as shown in figure 4.
As shown in figures 2 and 3, the gearing system starts from the small pinion (3) fixed on the shaft of prime mover (2). Pinion transmits this energy to epicyclic gears (6) through an intermediate gear (4). The epicyclic gears are mounted on ratchet (7) which is sandwiched between sun gear (5) and internal gear (8). For positive transmission of motion it is necessary to hold a ratchet. This is done by means of a pawl (22) which holds the ratchet teeth. While the pawl is not holding the ratchet it actually allows a free movement of gear train with respect to main shaft (27), thereby not effecting power transmission. Concurrent delatching of the two holding sub-mechanisms is done through a pawl delatching lever (29) as shown in figure 5. The delatching mechanism has an effectiveness in order of 10 times (i.e. it holds on a 20kg spring force and a force of 2 kg would suffice to delatch the mechanism for switching ON).
As shown in fig-1, on top of the mechanism core, a padlock arrangement is given. Indications of charging condition of spring as well as ON-OFF condition of switching device are clearly displayed on top. Front housing of the mechanism (not shown in figure) has cutouts for indications (33), padlock lever (32), ON and OFF push buttons (not shown in figure) and padlock slider (34). The logic circuit

takes care of the selection of mode and appropriately supplies power to required components (not shown in the figures).
The stored energy operator has three operational modes: Automatic, Manual and Lock. In Automatic operations charging is done by giving electrical pulse to motor which finally charges the main spring. For discharging electrical pulse is given to solenoids which will then release the charged spring. In manual mode of operation the charging is done manually by a handle and discharging by a press of a button provided on front facia of the operator.
According to another embodiment of the present invention, handle assembly is provided for manual charging. The hand assembly having a handle top (9), handle bottom (10) and handle lever (11) as shown in figure 3. This assembly has a lever {\\) which pushes the intexnal gear when handle (9) is pulled out. At resting position of handle lever gets disengaged from the internal gear (8) and does not interfere with internal gear.
There are basically two operations: Charging and Discharging. In a charging mode, Motor (1) is powered up and spring gets charged which finally disconnects the electrical connections of switching device. In the Discharging operation the energy stored in the spring is used for reverse movement of Rack (14) and making the switching device ON. When the spring is fully charged, it has to be held at that position. Mechanism comprising of cam and latch does this work and at the time of releasing electrical pulses are given to solenoids which disengages the latch.
At the time of charging, power is supplied to Motor and then motion is transmitted through gear train to the main shaft. Pawl, in its stable condition, is always engaged with the ratchet and provides positive transition of motion through epicyclic gear to internal gear. On the other side, the cam is restricted by latch which in turn is restricted by catch. This arrangement holds the shaft and allows it to rotate only in one direction. Main pinion (24), as shown in figure 4, which is fixed on main shaft also rotates with it and transfers its rotational motion to knob driver as linear motion. Knob driver finally drives the knob of switching device

and makes it OFF/RESET. After the spring is fully charged, switching device goes into OFF/RESET condition and indication on front facia shows 'CHARGED'. At the same time power to the Motor is cut off by toggle switch (20) mounted in base as shown in figure 1. Charging can also be done manually by using charging handle provided on front facia.
At the time of discharging, electrical pulses are given to solenoids. Solenoid provided at inner side of the LHS plate pushes the catch down. As the catch slides down, latch becomes free and allows cam to become free on shaft. The second solenoid on the outer side of RHS plate pushes down the pawl. Now the ratchet becomes free. As soon as the shaft becomes free, because of stored energy into the spring, spring pulls the knob driver and it comes back to its initial position with changing the knob position to ON condition of switching device.
ADVANTAGES OF THE INVENTION
1. The mechanism of the present invention minimizes the energy losses for operating switching devices.
2. The mechanism is simpler and uses less number of components.
The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The solenoid, cam, pawl, catch, shaft, spring, motor, gears, ratchet, handle, pins, pinion, switches, knob, lever, padlock, and indicators as stated do not limit the scope of the present invention. Any other components of technical equivalence can be used and still the invention can be arrived at. Such use of equivalent components will still be comprised within the true spirit of the invention without departing from the scope of the invention. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having

technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

We Claim
1. An improved stored energy motor operating mechanism for switching
devices, said mechanism comprising:
base means adapted to be mounted on the switching device;
core operating mechanism comprising motor means, gear system, shaft
means, rack and
pinion arrangement;
plurality of solenoid means, spring means;
catch-latch-cam arrangement;
pawl-ratchet arrangement;
wherein said catch-latch-cam arrangement work in concurrence with said
pawl-ratchet arrangement during charging and discharging of said spring
means;
wherein said motor means being operatively connected to said gear system
so as to rotate said shaft means whereby rotation of said shaft means
unidirectionally being controlled by said catch-latch-cam arrangement;
said gear system being operatively connected to said rack and pinion
arrangement such that said rack means moves in a substantial linear
direction thereby actuating knob of a conventional switching device during
charging;
wherein one of said plurality of solenoids pushes said catch-latch-cam
arrangement during discharging operation thereby attaining de-latching
position and wherein another solenoid of said plurality of solenoids pushes
pawl-ratchet arrangement attaining further de-latching position such that
said shaft means rotates freely such that said spring means pulls said rack
means thereby actuating the switching device.
2. Mechanism as claimed in claim 1 further comprising a toggle switch.

3. Mechanism as claimed in claim 1 further comprising a handle assembly for manual operation.
4. Mechanism as claimed in claim 3 wherein said manual operation comprises concurrence working of the catch-latch-cam arrangement with the pawl-ratchet arrangement during charging and discharging of the spring means.
5. Mechanism as claimed in claim 1 wherein said base means comprises recesses adapted for wire routing and channelizing power supply.
6. Mechanism as claimed in claim 1 wherein said gear system selectively comprising small pinion, epicyclic gears, intermediate gear, sun gear, internal gear and combination thereof,
7. Mechanism as claimed in claim 1 wherein said spring means comprising compression spring.
8. An improved stored energy motor operating mechanism for switching devices, said mechanism as herein substantially described and illustrated with the accompanying drawings.