FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION: DRAW OUT TYPE CIRCUIT BREAKER ASSEMBLY
APPLICANT: LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra
INDIA.
PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A) TECHNICAL FIELD
[0001] The present invention generally relates to circuit breakers and particularly to draw out type circuit breakers. The present invention more particularly relates to a safety device to provide safety against live terminals of fix part in draw out type circuit breaker
B) BACKGROUND OF THE INVENTION
[0002] The circuit breakers protect electrical circuit from overload and short circuit damages. The circuit breakers are used for main power distribution in large industrial plants. The cradle assemblies connected to main power are used to enclose heavy and large circuit breakers. Mechanical racking mechanisms are provided in the cradle assembly which can be operated manually or by using motors. The circuit breakers are provided with complimentary draw-out construction for easy installation and separation from the cradle assembly without disturbing main power connections.
[0003] The circuit breakers can be tested and serviced by mechanically moving it away from the cradle terminals coupled to the main power circuit. The complete isolation of the main power has to be achieved to ensure safety of the personnel during maintenance. Extreme caution needto be adopted to ensure complete isolation during maintenance for preventing any inadvertent lapse in safety mechanism.
[0004] The currently available safety shutters include complex operating lever arrangements with two point actuation mechanisms to engage and disengage circuit breakers. The actuating mechanisms are placed at extreme right and extreme left of safety shutters to open or close the safety shutters. Under such circumstances manual intervention required to open and close the safety shutters causes imprecise alignment of the opening and closing of the safety

shutters to actuate the shutters. Further, time is consumed for installation, maintenance and assembling of multiple shutters. Furthermore, the installation of the safety shutters is complex and requires precise alignment of openings to actuate the shutters. The cost of assembling and maintaining a complex operating lever and actuating mechanism is substantially high.
[0005] Hence, there exists a need to provide a mechanism for opening and closing a safety device while inserting or withdrawing out of the circuit breaker.
[0006] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and sstudying the following specification.
C) OBJECT OF THE INVENTION
[0007] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
[0008] The primary object of the present invention is to provide a mechanism in draw out type circuit breaker for opening and closing a safety device while inserting into the circuit breaker.
[0009] Another object of the present invention is to provide a mechanism in a draw out type circuit breaker for opening and closing a safety device while withdrawing out of the circuit breaker.
[0010] Yet another object of the present invention is to provide a safety device in draw out type circuit breaker to avoid shock or risk to a user during service.
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3 1 MAR 2010

[0011] Yet another object of the present invention is to provide a simple design for draw out type circuit breaker provided with a safety device.
D) SUMMARY OF THE INVENTION
[0012] The various embodiments of the present invention provide a mechanism in draw out type circuit breaker for opening and closing a safety device while inserting or withdrawing out of the circuit breaker.
[0013] According to one embodiment of the present invention, the draw out type circuit breaker includes a fixed part and a moving part. The moving part comprises of a current carrying pole capable of interrupting the main circuit with moving part adapter and withdrawal contact assemblies mounted on it. A sliding-in arrangement is provided which rests on the fixed part to engage or disengage the basic moving part from fixed part in lieu of maintenance or inspection of the circuit breaker. When basic moving part is disengaged from fixed part, the live current carrying part of the main circuit is isolated via a safety device by an operator to avoid shock. The safety device gets opened at the time when the moving part is engaged into the fixed part.
[0014] The fixed part includes a support, which is rested between the parallel horizontal members and connected to a side plate. A fixed terminal rests between the parallel horizontal members and side plate. The safety device is guided on guides against helical compression spring. The guides are mounted on circuit breaker which is fixed to the parallel horizontal members. The moving part includes a pole assembly capable of interrupting the main circuit with help of moving adapters connected to the pole assembly. The withdraw able contact assemblies are mounted on the moving adapters. At the time of engagement or disengagement of the circuit breaker, the withdrawable contact assemblies get inserted into fixed part terminal, thereby completing the main circuit.

[0015] The safety device is provided with a modular design used on individual or multiple pole/phase assemblies. The safety device includes a basic supporting structure, movable doors and a form strip. When the moving part is inserted into the fixed part, the withdrawable contact assemblies push the safety device on guides against spring force. Once the moving part touches the fixed part terminal, the fixed part terminal pushes the movable device door orthogonally against force of spring causing the doors to open an entrance for the fixed part terminal.
[0016] The safety device in the draw out type circuit breaker avoids shock or risk to a user during service of the circuit breaker. The invention provides a simple and a cost effective design for draw out type circuit breaker. The safety device is provided with a modular design which can be used on individual or multiple pole/phase assemblies.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0018] FIG. 1 illustrates a side perspective view of the fixed part assembly and safety device assembly according to one embodiment of the present invention.
[0019] FIG. 2 illustrates a side perspective view of the fixed part assembly, the moving part assembly and the safety device assembly according to one embodiment of the present invention.
[0020] FIG. 3 illustrates a side perspective view of safety device assembly according to one embodiment of the present invention.

[0021] FIG. 4 illustrates front side view and rear side view of mounting and guiding of safety device assembly according to one embodiment of the present invention.
[0022] FIG. 5 illustrates front view of moving terminal during initial condition with respect to safety device, while portraying self actuating mechanism according to one embodiment of the present invention.
[0023] FIG. 6 illustrates front view of moving terminal at final position according to one embodiment of the present invention.
[0024] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0025] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0026] The various embodiments of the present invention provide a mechanism in draw out type circuit breaker for opening and closing a safety device while inserting or withdrawing out of the circuit breaker. The draw out type circuit breaker includes a fixed part and a moving part. The moving part

comprises of a current carrying pole capable of interrupting the main circuit with moving part adapter and withdrawal contact assemblies mounted on it. A sliding-in arrangement is provided which rests on fixed part to engage or disengage the basic moving part from fixed part in lieu of maintenance or inspection of the circuit breaker. When basic moving part is disengaged from fixed part, live current carrying part of the main circuit is isolated via a safety device by an operator to avoid shock. The safety device gets opened at the time when the moving part is engaged into the fixed part.
[0027] The fixed part includes a support, which is rested between parallel horizontal members and connected to a side plate. A fixed terminal' rests between the parallel horizontal members, and side plate. The safety device is guided on guides against helical compression spring. The guides are mounted on circuit breaker which is fixed to the parallel horizontal members. The moving part includes a pole assembly, capable of interrupting the main circuit with help of moving adapters connected to the pole assembly. The Withdraw able contact assemblies are mounted on the moving adapters. At the time of engage or disengagement of the circuit breaker the withdrawable contact assemblies get inserted into fixed part terminal, and thereby completing the main circuit.
[0028] The safety device is provided with a modular design used on individual or multiple pole/phase assemblies. The safety device includes a basic supporting structure, movable doors and a form strip. When the moving part is inserted into the fixed part, the withdraw able contact assemblies pushes the safety device on guides against spring force. Once the moving part touches fixed part terminal, the fixed part terminal pushes the movable device door orthogonally against force of the spring causing the doors to open to provide an entrance for the fixed part terminal.

[0029] FIG. 1 illustrates side perspective view of fixed part assembly and safety device assembly according to one embodiment of the present invention. With respect to FIG. 1, the draw out type circuit breaker includes fixed part 1 and a moving part 20 (as shown in FIG. 2). The fixed part 1 is supported over a fixed part base plate 2. The moving part 20 comprises of a current carrying pole assembly 23 (as shown in FIG 2) capable of interrupting the main circuit with moving part adapter 21 (as shown in FIG 2) and withdrawal contact assemblies 9 mounted on it. A sliding-in arrangement 6 is provided which rests on fixed part 1 to engage or disengage the basic moving part 20 from fixed part 1 in lieu of maintenance or inspection of the circuit breaker.
[0030] The fixed part assembly 1 consists of base plate 2 and two parallel side plates 3 which are supported by top and bottom horizontal members 4 and 5. The fixed supports 8 are supported between the horizontal members 4, 5. The moving part 20 rests on parallel moving guides 7, which slide inside the grooves provided in side plates 3. These moving guides slide by means of a sliding in mechanism 6 resting on base plate 2.
[0031] When basic moving part 20 is disengaged from fixed part 1, live current carrying part of the main circuit is isolated via a safety device 10 by an operator to avoid shock. The safety device 10 gets opened at the time when the moving part 20 is engaged into the fixed part 1. The Fixed part 1 includes a support 8, which is rested between parallel horizontal members 4 and 5 connected to a side plate 3. A fixed terminal 14 rests between the parallel horizontal members 4, 5 and side plate 3.
[0032] FIG. 2 illustrates side perspective view of fixed part assembly, moving part assembly and safety device assembly according to one embodiment of the present invention. With respect to FIG. 2, the draw out type circuit breaker includes fixed part 1 and a moving part 20. The fixed part 1 is supported over a fixed part base plate 2 (as shown in FIG. 1). The moving part 20 comprises

of a current carrying pole assembly 23 capable of interrupting the main circuit with moving part adapter 21 and withdrawal contact assemblies 9 mounted on it. A sliding-in arrangement 6 is provided which rests on fixed part 1 to engage or disengage the basic moving part 20 from fixed part 1 for maintenance or inspection of the circuit breaker.
[0033] The fixed part assembly 1 consists of a base plate 2 and two parallel side plates 3 which are supported by top and bottom horizontal members 4 and 5 (as shown in FIG. 1). The fixed supports 8 are supported between the horizontal members 4, 5. The moving part 20 rests on parallel moving guides 7 (as shown in FIG. 1), which slide inside the grooves provided in side plates 3. These moving guides slide by means of a sliding in mechanism 6 (as shown in FIG. 1) resting on base plate 2.
[0034] When the moving part 20 is disengaged from fixed part 1, the live current carrying part of the main circuit is isolated via a safety device 10 by an operator to avoid shock. The moving part adapter 21 is bolted to the current carrying pole assembly 23 (as shown in FIG.2) capable of interrupting the main circuit. The safety device 10 gets opened at the time when the moving part 20 is engaged into the fixed part 1.
[0035] FIG. 3 illustrates a side perspective view of safety device assembly according to one embodiment of the present invention. With respect to FIG. 3, the safety device assembly 10 is provided with a basic supporting structure 23. Plurality of grooves 18 are provided on the supporting structure 23. Movable doors 11, 12 are provided in the safety device to slide. Further, the safety devicelO includes a Form strip 16 whose ends rests inside grove 17 provided on the movable doors 11, 12.
[0036] The safety device 10 is provided with a modular design used on individual or multiple pole/phase assemblies. The Safety device 10 includes a

basic supporting structure 23, movable doors 11 and 12, and a form strip 16. When the moving part 20 is inserted into the fixed part 1, the withdraw able contact assemblies 9 pushes the safety device 10 on guides 22 against spring force 19. Once the moving part 20 touches fixed part terminal 14, with further movement, fixed part terminal 14 pushes the movable device door 11 and 12 orthogonally against force of spring 16 causing the doors 11, 12 to open an entrance for the fixed part terminal 14.
[0037] FIG. 4 illustrates a front side view and rear side view of mounting and guiding of safety device assembly according to one embodiment of the present invention. With respect to FIG. 4, arrangement of the safety device 10 is as shown in the figure. The Safety device 10 is provided with a modular design used on individual or multiple pole/phase assemblies. The mounting assembly of the safety device 10 includes horizontal supporting members 4, 5 on which a moulded component called brackets 15 is situated. The Brackets 15 are moulded component provided with guides 22 and resting surface 13 as integral part of the bracket 15. The two brackets 15 are mounted on horizontal members 4, 5 using mounting screw. Front portion of resting surface 13 is designed in such a way that safety device 10 is click fitted on the resting surface 13. First the brackets 15 are mounted on horizontal members 4, 5.Hhelical springs 19 are inserted on guides 22, The safety device 10 is pushed on bracket 15 and click fitted on the bracket 15. Once the safety device 10 is inserted, it rests against the resting surface 13 against the spring force.
[0038] FIG. 5 illustrates a front view of moving terminal during initial condition with respect to safety device, while portraying self actuating mechanism according to one embodiment of the present invention. With respect to FIG. 5, a moving part 20 comprises of a current carrying pole assembly 23 (as shown in FIG.2) capable of interrupting the main circuit with moving part adapter 21 and withdrawal contact assemblies 9 mounted on it. When a moving part 20 slides in, the first withdraw able contact assemblies 9

touches the safety device 10 base and pushes the safety device 10 against spring 19 force. With further movement of the safety device 10 movable doors 11,12 touches fixed part terminal 14 and opens in orthogonal direction against a form strip 16. Further, the withdraw able contact assemblies 9 are inserted into fixed part terminal 14.
[0039] FIG. 6 illustrates front view of moving terminal at final position according to one embodiment of the present invention. With respect to FIG. 6 a moving part 20 comprises of a current carrying pole assembly 23 (as shown in FIG.2) capable of interrupting the main circuit with moving part adapter 21 and withdrawal contact assemblies 9 mounted on it. During sliding-out operation of the safety 10, as withdraw able contact assemblies 9 are moved back from Fixed terminal 14, safety device 10 are also moved back due to spring force 19. When the safety device 10 is moved out of fixed part terminal 14, movable doors 11, 12 gets closed due to form strip 16. When the moving part 20 is completely moved out, the safety device 10 rests against a resting surface 13.
G) ADVANTAGES OF THE INVENTION
[0040] The various embodiments of the invention provide a mechanism in a draw out type circuit breaker for the opening and closing of a safety device while inserting or withdrawing out of the circuit breaker. The safety device in draw out type circuit breaker avoids shock or risk to a user during service of the circuit breaker. The invention provides a simple and a cost effective design for draw out type circuit breaker. The safety device is provided with a modular design which can be used on individual or multiple pole/phase assemblies.
[0041] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the

invention with modifications. However, all such modifications are deemed to be within the scope of the claims.
[0042] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.

CLAIMS
What is claimed is:
1. A draw out type circuit breaker assembly, the assembly comprising:
a fixed part assembly;
a moving part assembly; and
a sliding-in arrangement;
a safety device mounted on the fix part assembly;
Wherein the fixed part, moving part and the sliding arrangement are
designed in such a way to provide the opening and closing of a safety
device while inserting or withdrawing the safety device out of the circuit
breaker.
2. The assembly according to claim 1, wherein the safety device is movable with respect to the fixed part in such a way that the movement of moving part causes the movement of safety device in the fixed part while allowing connection and disengagement of the fixed and the moving part.
3. The assembly according to claim 1, wherein the moving part comprising: an adapter;
a current carrying pole adapted to interrupt a main circuit with the
adapter; and
one or more withdrawable contact assemblies.
4. The assembly according to claim 1, wherein the fixed part assembly
comprising:
a base plate;
at least two side plates arranged parallel to each other;
a top horizontal member to support the at least two side plates;
a bottom horizontal member to support the at least two side plates;
one or more fixed supports arranged in parallel between the top horizontal
member and the bottom horizontal member; and

a f ixed terminal arranged between at least one or more fixed supports.
5. The assembly according to claim 1, wherein the sliding-in arrangement
comprising:
at least two brackets;
one or more guides attached to the bracket; and
one or more helical springs inserted on the guides.
6. The assembly according to claim 4, wherein the at least two brackets farther comprises a resting surface as an integral part.
7. The assembly according to claim 5, wherein the resting surface is provided with a profile so as to click fit a safety device.
8. The assembly according to claim 5, wherein the at least two brackets are mounted on the top horizontal member and the bottom horizontal member using mounting screw.
9. The assembly according to claim 1, further comprising one or more helical springs inserted on the guides which exerts a spring force on the safety device.
10. The assembly according to claim 1, further comprising a supporting structure including:
a plurality of grooves;
a movable devices; and
a form strip which rests inside the grove in the moving device.
11. The assembly according to claim 1, wherein the springs keeps the moving
device in closed position when the moving part is in the disconnected
condition.

12. The assembly according to any of the claims 1 to 10, wherein the sliding in of the moving part induce a force on the one or more withdrawable contact assemblies so that the contact assemblies come in contact with the safety device and pushes the safety device against the spring force.
13. The assembly according to claim 11, wherein the one or more withdrawable contact assemblies are moved back from fixed terminal and the safety device is moved back due to spring force during a sliding-out operation.
14. The assembly according to claim 12, wherein the moving device closes due to form strip when the safety device is moved out of the fixed part terminal.
15. The assembly according to claim 13, wherein the safety device rests against the resting surface when the moving part 20 is completely moved out of the assembly.