FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Easy Mounting Circuit Breaker"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: L& T House
Ballard Estate, P. 0. Box No. 278 Mumbai 400 072, INDIA
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

EASY MOUNTING CIRCUIT BREAKER
Field of invention
The present invention relates to circuit breakers and more particularly to a kinematic chain assembly of the circuit breaker,
Background of the Invention
A circuit breaker is a mechanical switching device, capable of making, carrying and breaking the current under normal circuit conditions and/or specified abnormal circuit conditions, such as short circuit. The circuit breakers known in the art normally have an automatic cutout essentially requiring a dedicated machine for the assembly. These circuit breakers are incompetent to form the assembly on machines other than dedicated machines as they substantially lack modularity in their design.
These prior art circuit breakers normally employ two axle bearings in connection with the actuating lever and support. The use of two axle bearings substantially limits the kinematic chain to have an optimal design in the light of the spaces occupied by it during the operation of the circuit breaker. Also, the prior art circuit breaker assemblies in the art normally include a mobile contact arm which is connected to a handle drum of the assembly, preferably in the upper half of the drum. The connection of the contact arm in the upper half of the drum structurally limits the movement of the arm to a greater extent. Moreover, the positioning of the contact arm in the upper half of the drum positions it in the proximity to the casing which reduces the safety of the circuit breaker.
For example, one such circuit breaker is shown in EP1173868 wherein the circuit breaker does not have a modular assembly thereby requiring an appropriate dedicated machine for the assembly of the circuit breaker. EP 1173868 also

discloses the kinematic chain having use of two axles. EP1173868 also discloses that the mobile contact arm 9 rotating in a clockwise motion following the movement of the handle wherein the contact arm 9 is connected to the handle drum in the upper half of the drum 10 limiting the movement of the contact arm 9 beyond certain extent.
Therefore, there exists a need of a novel circuit breaker that eliminates all the drawbacks of prior art.
Objects of the invention
It is an object of the present invention to provide a modular assembly of the circuit breaker with an improved design of kinematic chain.
Another object of the present invention is to add safety to the circuit breaker design by providing an external casing which safely encloses an operating kinematic chain having a three axle design in accordance with the present invention.
Further object of the present invention is to provide a quick make device that works in conjunction with the operating kinematic chain of the present invention.
Summary of the invention
Accordingly, the present invention provides a circuit breaker having an operating kinematic chain, a solenoid assembly and a deyon cell that are modularly assembled and positioned within an external casing. The operating kinematic chain comprises an operating handle that connects to an operating arm through a drum. The operating arm connects to an actuating lever through a latch.

The operating kinematic chain includes a support having a first axle bearing and a second axle bearing supported thereon. The first axle bearing facilitates rotation of the latch. The second axle bearing facilitates rotation of the actuating lever. The support connects to a movable contact lever configuring a third axle bearing therebetween. The third axle bearing facilitates rotation of the movable contact lever.
The operating kinematic chain includes a main spring and a secondary spring. The main spring extends between the actuating lever and the support. The secondary spring extends between the support and the movable contact lever. The main spring counteracts an action force delivered by the handle. The secondary spring drives the return movement of the actuating lever.
The operating kinematic chain includes a quick make device having a pin, a lever and a return spring. The lever engages with at least a portion of the movable contact lever. The pin connects to the support. The return spring assists in rotational movement of the lever around the pin,
Brief description of the invention
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
FIG. 1 is a general exploded view of a circuit breaker device constructed in accordance with the present invention;
FIG. 1A is a partly exploded view of an operating kinematic chain of the circuit breaker device of FIG. 1;

FIG. 2 is a top perspective view of the operating kinematic chain of the circuit breaker device of FIG. 1;
FIG. 3 is a side perspective view of the operating kinematic chain of the circuit breaker device of FIG. 1;
FIG. 4 is a front perspective view of the operating kinematic chain of the circuit breaker device of FIG. 1 illustrating details of a support;
FIG. 5 is a side view of the operating kinematic chain of the circuit breaker device of FIG. 1 illustrating a handle operating in a starting position;
FIG. 6 is a side view of the operating kinematic chain of the circuit breaker device of FIG. 1 illustrating the handle operating in an intermediate position;
FIG. 7 is a side view of the operating kinematic chain of the circuit breaker device of FIG. 1 illustrating the handle operating a final position;
FIG. 8 is a top perspective exploded view of the operating kinematic chain of the circuit breaker device of FIG. 1 illustrating details of a lever;
FIG. 9 is a top perspective view of the operating kinematic chain of the circuit breaker device of FIG. 1 illustrating details of the lever;
FIG. 10 is a partially enlarged side view of the operating chain of the circuit breaker device of FIG. 1 illustrating a quick make device;
FIG. 11 is a side view of the operating chain of the circuit breaker device of FIG. 1 illustrating the quick make device operating in a starting position;

FIG. 12 is a side view of the operating chain of the circuit breaker device of FIG. 1 illustrating the quick make device operating an intermediate position; and
FIG. 13 is a side view of the operating chain of the circuit breaker device of FIG. 1 illustrating the quick make device operating in a final position.
Detail description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
Referring to FIG. 1, the circuit breaker 1 constructed in accordance with the present invention is shown. The circuit breaker 1 includes an external casing formed by a first casing half 10 and a second casing half 11. The first casing half 10 and the second casing half 11 adjoin to enclose an operating kinematic chain 12, a solenoid assembly 13 and a deyon cell 14. The deyon cell 14 provides an electric arc to the circuit breaker 1 in this one preferred embodiment. However, it is understood here that other types of sources for providing the electric arc to the circuit breaker may be utilized in other alternative embodiments of circuit breaker 1.
Referring to FIG. 1 A, the kinematic chain 12 includes an operating handle 2 that connects to a drum 3, The drum 3 connects to an operating arm 4 that further connects to a latch 5. The kinematic chain 12 includes a first axle bearing 6. The latch 5 is adapted to freely rotate around the first axle bearing 6. The latch 5 removably connects to an actuating lever 7. The kinematic chain 12 includes a second axle bearing 8. The actuating lever 7 is adapted to rotate around the second axle bearing 8. The first axle bearing 6 and the second axle bearing 8 are pins in this one particular embodiment of the present invention. However, it is

understood here that the configuration of the first axle bearing 6 and the second axle bearing 8 may not be limited to pins in other alternative embodiments of the circuit breaker 1. The operating kinematic chain 12 includes a flag indicator arm 15. In this one embodiment, the drum 3 has a rectangular opening 17 adapted for joining further components by a common shaft (not shown). Alternatively, the rectangular opening 17 may be utilized to couple the circuit breaker 1 to other auxiliary devices. The rectangular shape of the opening 17 is of optimal design in this one particular embodiment. However, it is understood that the shape of opening 17 may vary per intended application of the kinematic chain 12 in other alternative embodiments of the circuit breaker 1.
As shown in FIGS. 1A and 2, the first axle bearing 6 and the second axle bearing 8 are supported on a support 20 in this one preferred embodiment. The support 20 is connected to a mobile contact lever 21. The operating kinematic chain 12 includes a secondary spring 22 that extends between the actuating lever 7 and the support 20, The secondary spring 22 is adapted to drive the return movement of the actuating lever 7. The movable contact lever 21 is adapted to rotate around the second axle bearing 8 for moving signal of the closure or opening of the contacts.
As shown in FIGS. 3- 4, a hook is joined between the mobile contact lever 21 and the support 20 to configure a third axle bearing 9. The kinematic operating chain 12 includes a main spring 25 that is adapted to counteract the action force delivered by the handle 2. The main spring 25 extends between a fixed point part of the support 20 and the movable contact lever 21. The support 20 facilitates modular mounting operation wherein all the components of the kinematic operating chain 12 are modularly assembled on the support 20 for being comfortably mounted inside the circuit breaker 1. Accordingly, the kinematic chain 12 acts as a stand-alone piece in this one part. The kinematic chain 12 eliminates the need of mounting components on the external casing of the circuit breaker 1.

Referring now to FIG. 5, an operation of the kinematic chain 12 is illustrated wherein the operating handle 2 is in a starting position, in the starting position, the movable contact lever 21 is not in contact with a fixed contact 24. When the handle 2 is rotated, a rotary motion of the handle 2 is transmitted by arm 4 (refer to FIG. 1A) to the latch 5 (refer to FIG- 1A). The latch 5 rotates around the first axle bearing 6 until its lower portion engages with the operating lever 7 (refer to FIG. 1A). The engagement between the latch 5 and the operating lever 7 allows the first axle bearing 6, the support 20 and the movable contact lever 21 to rotate around the second axle bearing 8. In this position, the main spring 25 counteracts against the force delivered by the handle 2.
Referring to FIG. 6, an operation of the kinematic chain 12 is illustrated wherein the operating handle 2 is in an intermediate position. In the intermediate position, the contact is in a closed position wherein the movable contact lever 21 is in contact with the fixed contact 24. In this position, the movable contact lever 21 is free to rotate around the third axle bearing 9 facilitating the latch 5, the lever 7 and the support 20 (refer to FIG. 1 A) to rotate around the second axle bearing 8. In this position, the main spring 25 acts on the movable contact lever 21 and forces the movable contact lever 21 against the fixed contact 24.
Referring to FIG. 7, an operation of the kinematic chain 12 is illustrated wherein the operating handle 2 is in a final position. In the final position, the contact is in a closed position such that the movable contact lever 21 is in contact with the fixed contact 24. In this position, the handle 2 is in stable position and the main spring 25 continues to act on the movable contact lever 21 to force the movable contact lever 21 against the fixed contact 24.
As shown in FIGS. 8-9, the operating actuating lever 7 is having an upper end portion and a lower end portion. The upper end portion includes the second axle bearing 8. The lower end portion includes a shaft 27. The shaft 27 is adapted to be

connected to the bimetallic in this one preferred embodiment (not shown). The operating actuating lever 7 includes a first part 7A and a second part 7B that connect such that the second axle bearing 8 assists in connection of the first part 7A and the second part 7B,
Referring to FIGS. 10-13, the operating kinematic chain 12 includes a quick make device 31 which comprises a lever 32 and a return spring 33. The lever 32 is having "L" shape in this one preferred embodiment. The lever 32 is configured to rotate around a pin 34 which is having a front end 35 adapted to engage with at least a portion of the movable contact lever 21. The return spring 33 assists in a returning motion of the lever 32. The lever 32 is configured to operate with a tooth 36 of the drum 3. The pin 34 engages with the support 20 (as shown in FIG. 4) in this one particular embodiment. The circuit breaker 1 operates in three positions including a starting position, an intermediate position, and a final position facilitated by the quick make device.
Referring back to FIG. 11, an operation of the kinematic chain 12 is illustrated wherein the quick make device 31 is in a starting position. In the starting position, the movable contact lever 21 is not in contact with the fixed contact 24. In this position, the quick make device 31 is not in operation.
Referring back to FIG. 12, an operation of the kinematic chain 12 is illustrated wherein the quick make device 31 is in an intermediate position. In the intermediate position, the movable contact 21 is not in contact with the fixed contact 24. However, the quick make device 31 is already in operation. In this position, the movable contact lever 21 is free to rotate around the third axle bearing 9 facilitating the latch 5, the lever 7 and the support 20 (as illustrated in FIG. 1A) to rotate around the second axle bearing 8. In this position, an engagement between the front end 35 and movable contact lever 21 is established.

Referring back to FIG. 13, an operation of the kinematic chain 12 is illustrated wherein the quick make device 31 is in a final position. In the final position, the movement of the handle 2 facilitates the tooth 36 to engage with the lever 32 thereby causing the rotation of the lever 32. This disengages the lever 32 from the movable contact lever 21 thereby causing a snap action of the movable contact lever 21 towards the fixed contact 24.
Advantages of the present invention:
1. The support 20 of the operating kinematic chain 12 facilitates modular mounting of the components within the first casing half 10 and the second casing half 11 of the circuit breakerl, thereby advantageously eliminating the need of mounting components of the circuit breaker 1 on the first casing half 10 and the second casing half 11.
2. The first axle bearing 6, the second axle bearing 8 and the third axle bearing 9 of the operating kinematic chain 12 advantageously facilitate the operating kinematic chain 12 to optimally operate the circuit breaker 1 during the operation.
3. The lever 32 and the return spring of the quick make device 31 advantageously control the rotational speed of the movable contact lever 21 irrespective of the rotational speed of the operating handle 2.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient,

but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We Claim:
1. A circuit breaker having an operating kinematic chain, a solenoid
assembly and a deyon cell assembled modularly within an external casing,
characterized in that, the operating kinematic chain comprising:
an operating handle connecting to an operating arm through a drum, the operating arm connecting to an actuating lever through a latch;
a support having a first axle bearing and a second axle bearing supported thereon, the first axle bearing facilitating rotation of the latch, the second axle bearing facilitating rotation of the actuating lever, the support connecting to a movable contact lever configuring a third axle bearing therebetween, the third axle bearing facilitating rotation of the movable contact lever;
a main spring and a secondary spring, the main spring extending between the actuating lever and the support, the secondary spring extending between the support and the movable contact lever, the main spring counteracting an action force delivered by the handle, the secondary spring driving the return movement of the actuating lever; and
a quick make device having a pin, a lever and a return spring, the lever engaging with at least a portion of the movable contact lever, the pin connecting to the support, the return spring assisting in rotational movement of the lever around the pin.
2. The circuit breaker as claimed in claim 1, wherein the drum includes a tooth adapted to operate the lever during the working of the quick make device.
3. The circuit breaker as claimed in claim 1, wherein the drum includes a rectangular opening adapted to couple the circuit breaker to an auxiliary device.
4. The circuit breaker as claimed in claim 1, wherein the first axle bearing is a pin.

5. The circuit breaker as claimed in claim 1, wherein the second axle bearing is a pin.
6. The circuit breaker as claimed in claim 1, wherein the third axle bearing is a hook.