Claims:
1. A circuit breaker for breaking an electrical circuit during short circuit, the circuit breaker comprising:
a torsion spring that provides clockwise torque to a latch bracket; and
a trip plate assembly that, during said short circuit, is rotated to enable a latch link and said latch bracket to rotate;
wherein, the impact force generated during switching operations, on the trip plate assembly is reduced.
2. The circuit breaker as claimed in claim 1, wherein horizontal distance between pivot of the latch bracket and roller pin (c-distance) is reduced.
3. The circuit breaker as claimed in claim 2, wherein the reduction in the c-distance is brought about by moving the latch bracket closer to the roller pin.
4. The circuit breaker as claimed in claim 2, wherein the reduction in c-distance causes a reduction in trip force.
5. The circuit breaker as claimed in claim 1, wherein during fault condition, the trip plate assembly is rotated such rotation of latch link is enabled.
6. The circuit breaker as claimed in claim 1, wherein a torsion spring is inserted in the latch bracket pivot with the fixed leg resting on the y-pole of contacting system and the moving leg located on the latch bracket.
7. The circuit breaker as claimed in claim 6, wherein due to reduced eccentricity and insertion of torsion spring, low static or impact force gets transmitted onto the trip plate, hence reducing its surface damage.
8. The circuit breaker as claimed in claim 6, wherein the torsion spring provides a clockwise torque to latch bracket, allowing it to rotate and, in turn, allow the latch link to rotate and open the contacts during trip operation.
9. The circuit breaker as claimed in claim 8, wherein the torsion spring prevents the latch bracket from locking up.
10. The circuit breaker as claimed in claim 2, wherein reducing c-distance leads to overall reduction in size of the mechanism.
, Description:
TECHNICAL FIELD
[1] The present disclosure relates generally to circuit breakers. In particular, the present invention relates to a circuit breaker with reduced trip force, to protect the trip plate assembly from surface damage.

BACKGROUND
[2] Circuit breakers are mechanical switching devices capable of carrying and breaking current circuits. Under normal circuit conditions, circuit breakers carry currents and when there is an abnormal circuit condition, circuit breakers are employed to break the circuit as well.
[3] During adverse conditions like short circuit, the current rises to a high level. This current may damage elements in the electrical system. Circuit breakers are, in particular, used to protect the electrical elements from damage during adverse conditions. During these conditions, the circuit is opened to protect the system.
[4] During an adverse event, a trip command is given to the mechanism, for it to open the circuit. This tripping of mechanism happens when a force greater than the trip force is applied on trip plate of the operating mechanism.
[5] Trip force is a function of mechanism main spring force, the contact pressure of contact system and the lengths of various mechanism links. As contact pressure increases, for higher current ratings, the mechanism spring force increases, causing an increase in the trip force of the operating mechanism. With higher forces, the impact generated on stopping the links is also high and this tends to damage the trip plate surface thereby increasing the trip force. The trip force increment here could be of any magnitude, depending on the extent of damage of the trip plate surface.
[6] US Patent 4238750A talks about an arrangement of two eccentrically placed latch mechanisms to reduce the magnitude of forces acting on the trip mechanism, by translating the linear force into rotational force of lesser magnitude. This arrangement works fine for lower forces (contact pressure and mechanism spring) and where impact energy on account of link movements are less. However, for higher forces the impact energy increases substantially. This impact energy combined with the eccentricity of the second latch mechanism will tend to transfer impact energy onto the trip plate, thereby damaging its surface.
[7] There is, therefore, a requirement in the art for a circuit breaker mechanism that can operate at high currents and can have an increased life-span by reducing the force registered on the trip plate assembly.

OBJECTS OF THE INVENTION
[8] A general object of the present invention is to provide a circuit breaker with a mechanism that causes lower impact force to register on the trip plate assembly.
[9] Another object of the present invention is to provide a circuit breaker with a reduced c-distance in its mechanism.
[10] Another object of the present disclosure is to provide a circuit breaker with a torsion spring aided tripping in mechanism.
[11] Another object of the present invention is to provide a circuit breaker with low trip force.
[12] Another object of the present invention is to provide a circuit breaker with longer working life.
[13] Another object of the present invention is to provide a circuit breaker with a reduced mechanism size.
[14] Another object of the present invention is to provide a circuit breaker for high current applications.

SUMMARY
[15] Embodiments explained herein relate to circuit breakers for the protection of electrical elements against abnormal operation conditions such as short-circuits or overloads. In particular, the present invention relates to a circuit breaker with a torsion spring assisted mechanism that can be used to close or open a circuit depending on the trip command it receives.
[16] The present invention discloses a circuit breaker mechanism comprising a toggle link, a latch link, a latch bracket, pivot points for toggle link and latch link, an extension spring and a torsion spring. In an aspect of the present invention, the distance between the latch bracket pivot and the roller pin is referred to as c-distance, which is responsible for dictating the amount of trip force required to rotate the trip plate assembly.
[17] In an aspect, the rotation of the latch bracket and latch link is limited by the trip plate assembly. In an instance, during the trip operation, the trip plate assembly 5 is rotated during the trip operation, such that a path is cleared for the rotation of latch bracket 4 and, subsequently, latches link’s rotations. The trip force f3, that is, the force required to rotate the trip plate assembly is a function of the amount of force f4 by which the latch bracket 4 is held by the trip plate assembly to prevent its rotation and the co-efficient of friction between he latch bracket and the trip plate assembly.
[18] In another aspect of this invention, as the circuit breaking mechanism is triggered, the toggle link pivots and impacts latch link. This impact energy transmits through latch link and latch bracket to trip plate assembly. On account of high force f1 due to extension spring, the force transmitted to the trip plate assembly is high. In another aspect of the present invention, the c-distance determines the amount of impact force f4 that will register on trip plate assembly, through latch bracket. Greater the c-distance, higher the impact force f4 as well as trip force f3.
[19] In an embodiment of the present invention, c-distance is decreased to reduce the trip force f3. However, it will lead to no-tripping issue due to locking of latch bracket on account of lack of rotational force t2 on it. In another embodiment of the present invention, a torsion spring is used to overcome the drawback of reducing the c-distance, as earlier mentioned. The torsion spring provides a clockwise torque to the latch bracket and enables it to rotate during the trip operation, after the trip plate assembly has cleared the path.
[20] In accordance with another embodiment of the present invention, reduction in c-distance reduces the damage caused to the surface of the trip plate assembly and owing to the fact that trip plate assembly is brought closer to latch bracket, there is a possibility of reducing the size of the circuit breaker mechanism.

BRIEF DESCRIPTION OF DRAWINGS
[21] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[22] FIG. 1 illustrates section view of mechanism assembly of a typical circuit breaker used in the art.
[23] FIG. 2 illustrates section view of mechanism assembly of a typical circuit breaker used in art, when the said circuit breaker is in the “ON” position.
[24] FIG. 3 illustrates section view of mechanism assembly of a typical circuit breaker used in art, when the said circuit breaker is in the “OFF” position.
[25] FIG. 4 illustrates section view of mechanism assembly of a circuit breaker with a torsion spring and y-pole, of the present invention.
[26] FIG. 5 illustrates the close-up section of the torsion spring assembly.

DETAILED DESCRIPTION
[27] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such details as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[28] Embodiments explained herein relate to circuit breakers for the protection of electrical elements against abnormal operation conditions such as short-circuits or overloads. In particular, the present invention relates to a circuit breaker with a torsion spring assisted mechanism that can be used to close or open a circuit depending on the trip command it receives.
[29] Embodiments explained herein relate to circuit breakers for the protection of electrical elements against abnormal operation conditions such as short-circuits or overloads. In particular, the present invention relates to a circuit breaker with a torsion spring assisted mechanism that can be used to close or open a circuit depending on the trip command it receives.
[30] The present invention discloses a circuit breaker mechanism comprising a toggle link, a latch link, a latch bracket, pivot points for toggle link and latch link, an extension spring and a torsion spring. In an aspect of the present invention, the distance between the latch bracket pivot and the roller pin is referred to as c-distance, which is responsible for dictating the amount of trip force required to rotate the trip plate assembly.
[31] In an aspect, the rotation of the latch bracket and latch link is limited by the trip plate assembly. In an instance, during the trip operation, the trip plate assembly 5 is rotated during the trip operation, such that a path is cleared for the rotation of latch bracket 4 and, subsequently, latches link’s rotations. The trip force f3, that is, the force required to rotate the trip plate assembly is a function of the amount of force f4 by which the latch bracket 4 is held by the trip plate assembly to prevent its rotation and the co-efficient of friction between the latch bracket and the trip plate assembly.
[32] In another aspect of this invention, as the circuit breaking mechanism is triggered, the toggle link pivots and impacts latch link. This impact energy transmits through latch link and latch bracket to trip plate assembly. On account of high force f1 due to extension spring, the force transmitted to the trip plate assembly is high. In another aspect of the present invention, the c-distance determines the amount of impact force f4 that will register on trip plate assembly, through latch bracket. Greater the c-distance, higher the impact force f4 as well as trip force f3.
[33] In an embodiment of the present invention, c-distance is decreased to reduce the trip force f3. However, it will lead to no-tripping issue due to locking of latch bracket on account of lack of rotational force t2 on it. In another embodiment of the present invention, a torsion spring is used to overcome the drawback of reducing the c-distance, as earlier mentioned. The torsion spring provides a clockwise torque to the latch bracket and enables it to rotate during the trip operation, after the trip plate assembly has cleared the path.
[34] In accordance with another embodiment of the present invention, reduction in c-distance reduces the damage caused to the surface of the trip plate assembly and owing to the fact that trip plate assembly is brought closer to latch bracket, there is a possibility of reducing the size of the circuit breaker mechanism.
[35] FIG.1 illustrates a section view of the mechanism assembly of a typical circuit breaker used in the art. The toggle link 2 is pivoted on to latch link 3 at pivot point 2a. The toggle link 2 is loaded by extension spring 1.
[36] The latch link 3 is pivoted at pivot point 3a, which is at a certain distance from the toggle link pivot point 2a. This causes the linear force f1 due to extension spring 1 toggle link pivot point 2a to be transmitted to latch link pivot point 3a as a torque t1 in the anti-clockwise direction. However, the rotation of the latch link 3 is limited by the latch bracket 4 through a roller pin 4a which is within the latch bracket 4.
[37] The latch bracket 4 is pivoted at point 4b which is at a certain distance from roller pin 4a. This distance between the latch bracket pivot point 4b and the roller pin 4a is referred to as c-distance. This causes a clockwise torque t2 on latch bracket 4 due to the linear force f2 produced from the torque force t1 at latch link 3. However, the rotation of the latch bracket 4 is limited by the trip assembly 5 during making and breaking of the circuit.
[38] In an instance, the trip plate assembly 5 is rotated during the trip operation, such that a path is cleared for the rotation of latch bracket 4 and, subsequently, latches link’s 3 rotation. The trip force f3, that is, the force required to rotate the trip plate assembly 5 is a function of the amount of force f4 by which the latch bracket 4 is held by the trip plate assembly 5 to prevent its rotation and the co-efficient of friction between the latch bracket 4 and the trip plate assembly 5.
[39] FIG. 2 and FIG.3 illustrate the section view of the mechanism assembly of a typical circuit breaker used in the art, when the circuit breaker is in the “ON” position and “OFF” position, respectively. The state of the circuit breaker can be toggled by lever 6. As the mechanism is toggled, the toggle link 2pivots around point 2a and impacts latch link 3. This impact energy transmits through latch link 3 and latch bracket 4 to trip plate assembly 5. On account of high force f1 due to extension spring 1, the force transmitted to the trip plate assembly 5 is high.
[40] In an aspect of the present invention, the c-distance determines the amount of impact force f4 that will register on trip plate assembly 5, through latch bracket 4. Greater the c-distance, higher the impact force f4 as well as trip force f3. By reducing c-distance one can reduce the trip force f3 however it will lead to no-tripping issue due to locking of latch bracket 4 on account of lack of rotational force t2 on it.
[41] FIG. 4 illustrates the section view of the mechanism assembly of the circuit breaker, in accordance with an embodiment of the present invention. The latch bracket pivot point 4b is brought closer to the roller pin 4a, thereby reducing the c-distance. This causes a reduction in both static and impact forces registering on the trip plate assembly 5.
[42] In an aspect of the present invention, reducing c-distance causes reduction in impact and static forces on trip plate assembly 5. However, it can also, possibly cause the locking of latch bracket 4, even after that trip plate assembly 5 has cleared the path, owing to the inadequacy of torque t2, during trip operation.
[43] FIG. 5 illustrates a close up of the torsion spring 7 sub-assembly in the circuit breaker, in accordance with an embodiment of the present invention. The body of torsion spring 7 is inserted in the latch bracket pivot point 4b. The torsion spring’s fixed leg rests on the y-pole 8 of the contact system and the moving leg rests on the latch bracket.
[44] In accordance with an embodiment of the present disclosure, the reduction in c-distance brings the trip plate assembly 5 closer to the latch bracket 4, and this allows for the reduction in the size of the mechanism.
[45] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[46] The present disclosure provides a circuit breaker with a mechanism that causes lower impact force to register on the trip plate assembly.
[47] The present disclosure provides a circuit breaker with a reduced c-distance in its mechanism.
[48] The present disclosure provides a circuit breaker with a torsion spring aided tripping in mechanism.
[49] The present disclosure provides a circuit breaker with low trip force.
[50] The present disclosure provides a circuit breaker with longer working life.
[51] The present disclosure provides a circuit breaker with a reduced mechanism size.
[52] The present disclosure provides a circuit breaker for high current applications.