CLIAMS:1. A circuit breaker having at least one knob (1), at least one contact link (2), at least one moving contact (3), at least one fixed contact (5), at least one mainspring (6), at least one support pin (8), and at least one spring mounting pin (9), the circuit breaker CHARACTERIZED IN THAT ensuring zero torque on a latch (4) comprising:
a U-shaped pin (7); and
a latch (4) having a circular profile with a center, wherein
one end of the U-shaped pin (7) is coupled to the knob (1) and other end of the U-shaped pin (7) is configured to slide to at least one slot provided on the contact link (2);
the latch (4) is coupled with the contact link (2) and is configured to rotate in anti-clockwise direction;
the latch (4) is configured to restrict the sliding of the U-shaped pin (7) along the slot of the contact link (2) there by making a revolute joint, such that during latching, the circular profile enables a reaction force to act at a pivot of the latch (4) and the reaction force passes through a center of U-shaped pin and the center of curvature of a latching area of the latch (4) to ensure zero torque on the latch (4).

2. The circuit breaker as claimed in claim 1, wherein the latch (4) is configured for latching the U-shaped pin (7) during an operation of the circuit breaker.

3. The circuit breaker as claimed in claim 1, wherein the U-shaped pin (7) is in contact with the circular profile on the latch (4) which enables the reaction force reaction acts at the pivot of the latch (4).

4. The circuit breaker as claimed in claim 1, wherein the center present at the pivot of the latch (4) enables the reaction force direction passing through the pivot of the latch (4).

5. The circuit breaker as claimed in claim 1 is configured to perform at least one operation selected from OFF – ON operation and/or ON – OFF operation.

6. The circuit breaker as claimed in claim 1 is configured to perform at least one function selected from ON, OFF, Trip, or any combination thereof.

7. The circuit breaker as claimed in claim 1, wherein the circular profile on the latch (4) has the center at pivot of the latch component, wherein in ON condition, the line of action of force passes through the pivot of the latch (4) component.
,TagSPECI:TECHNICAL FIELD

[001] The present subject matter described herein, in general, relates to switch gear, and more particularly to low voltage switch gear or circuit breakers having an improved ON, OFF and Trip functions.

BACKGROUND

[002] Circuit breaker(s) is/are used to protect the device from overload and short circuit current. Circuit breakers like molded case circuit breaker (MCCB) can be functionally divided into 3 sub systems namely, mechanism, contact system, and release.

[003] Existing circuit breaker mechanism is designed for ON, OFF and Trip functions. However, in order to achieve the same, apart from the components like knob, contact links, moving contacts, fixed contacts, mainspring, support pins, and spring mounting pins, the existing breakers uses two or more latches. The figure 1 shows the existing mechanism of the circuit breakers. The two components small latch and big latch are the two latches are the two latch components.

[004] Hence, the major drawback in the existing breaker systems is that they us multiple components and complex kinematics, which makes the overall working of the breakers more complex. Further, due to increase in the number of components in the circuit breakers, the overall cost of the breakers also increases.

[005] Thus, there is a particular need to provide a specific circuit breaker which has fewer components in it and still provides same and/or advanced functions and operation as provided by the existing circuit breakers.

SUMMARY OF THE INVENTION

[006] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[007] One aspect of the present invention is to provide a lesser tripping force.

[008] Another aspect of the present invention is to provide higher opening velocity due to less number of components.

[009] Another aspect of the present invention is to provide lesser number of mechanism components.

[0010] Yet another aspect of the present invention is to perform all the basic function of the circuit breaker that includes but not limited to ON, OFF, and Trip with lesser number of components.

[0011] According to the present invention, the foregoing and other objects and advantages are attained by providing a circuit breaker having at least one knob (1), at least one contact link (2), at least one moving contact (3), at least one fixed contact (5), at least one mainspring (6), at least one support pin (8), and at least one spring mounting pin (9), the circuit breaker ensuring zero torque on a latch (4). The circuit breaker comprises a U-shaped pin (7) and a latch (4) having a circular profile with a center. The one end of the U-shaped pin (7) is coupled to the knob (1) and other end of the U-shaped pin (7) is configured to slide to at least one slot provided on the contact link (2). The latch (4) is coupled with the contact link (2) and is configured to rotate in anti-clockwise direction. The latch (4) is configured to restrict the sliding of the U-shaped pin (7) along the slot of the contact link (2) there by making a revolute joint, such that during latching, the circular profile enables a reaction force to act at a pivot of the latch (4) and the reaction force passes through a center of U-shaped pin and the center of curvature of a latching area of the latch (4) to ensure zero torque on the latch (4).

[0012] In one implementation, the present invention provides the operating mechanism of circuit breakers that are used to perform the primary functions like ON, OFF, and Trip. The primary functions are achieved using more than two components and of complex kinematics in the existing circuit breaker systems. The present invention achieves the primary functions using two components i.e., the U-shaped pin (7) and the Latch (4). The profile and placement of these two components are in such a way that the primary functions of a circuit breaker are fulfilled.

[0013] In one implementation, the kinematics by using the present invention is simple, due to which the reliability and robustness increases.

[0014] Another essential parameter in any circuit breaker system is that the circuit breaker should meet the tripping force requirement of the system. This tripping force may vary from every circuit breaker depending on the current rating and this tripping force needs to be as low as possible. The components of the present invention are placed in such a way that the magnitude of tripping force is nothing but to overcome the friction force of one joint.

[0015] Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0016] Figure 1 illustrates various components in accordance with an embodiment of the present subject matter.

[0017] Figure 2 illustrates the OFF position of the circuit breaker which can be turned ON, in accordance with an embodiment of the present subject matter.

[0018] Figure 3 illustrates the knob rotation in anti-clockwise direction, in accordance with an embodiment of the present subject matter.

[0019] Figure 4 illustrates an assembly in ON condition, in accordance with an embodiment of the present subject matter.

[0020] Figure 5 illustrates a moving contact assembled on the contact link as pin joint, in accordance with an embodiment of the present subject matter.

[0021] Figure 6 illustrates one end of a main spring connected on the contact link and the other end connected to the rigid section of housing, in accordance with an embodiment of the present subject matter.

[0022] Figure 7 illustrates the latching area that consists of one end of U-pin, contact link and latch, in accordance with an embodiment of the present subject matter.

[0023] Figure 8 illustrates an existing mechanism of MCB.

[0024] Figure 9 illustrates a reaction force direction through U-pin and latch, in accordance with an embodiment of the present subject matter.

[0025] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0026] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0027] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0028] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0029] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0030] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0031] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0032] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0033] The invention relates to the operating mechanism of circuit breakers which performs the primary functions like ON, OFF, and Trip. This present mechanism does these primary functions in two components through U-pin and latch. The profile and placement are in such a way that the primary functions of a circuit breaker are fulfilled.

[0034] Since the kinematics is simple, the reliability and robustness of the present invention increases. Further, the U-pin and latch components of this present mechanism are placed in such a way that the magnitude of tripping force is nothing but to overcome the friction force of one joint.

[0035] The present invention consists of a Knob (1), a U-pin (7), and a contact link (2), latch (4), a moving contact (3), a mainspring (6), a support pin (8), a spring mounting pin (9), a fixed contact(5) as shown in figure 1. The components are arranged as shown in Figure 1.

[0036] The figure 2 shows the OFF position which can be turned ON. The Knob and contact link is pin joint on the housing. The one end of U-pin is pin joined to the knob and the other can slide to the slot in the contact link. The latch component is mounted pin joint on the contact link and it is spring loaded in such a way that it tries to rotate always in anti-clockwise direction. The latch always stops the movement of the U-pin along the slot of the contact link there by making it a pin joint.

[0037] The moving contact is also assembled on the contact link as pin joint as shown in the figure 5. The main spring one end is connected on the contact link and the other end is connected to the rigid section of housing as shown in figure 6.

OFF – ON operation: In this operation the mechanisms prime function is to establish the contact between the moving contact and the fixed contact. In order to achieve this, the knob is rotated in anti-clockwise direction as shown in figure 3. When the knob is rotated the motion is transferred to the U-pin which in turn transfers the rotation to the contact link. As we know that one end of U-pin which is connected to the contact link has tendency to slide along the slot of the contact link. But this sliding movement is arrested by the latch (4).

As the movement of the knob pin is arrested by the latch, the slider joint is converted in to pin joint. This enables the rotation from the knob is transferred to contact link. As the knob is rotated towards the ON position the moving contact which is mounted on the contact link, rotates and touches the fixed contact.

During this operation the main spring which is connected to contact link and housing, is loaded so that when the knob rotation is few degrees away from the ON position, there is a toggle point of the links i.e., the reaction force from the loaded main spring will generate torque on knob in anti-clock wise direction. This is possible due to the length of the links i.e., Distance between knob pivot to knob pin pivot (on the knob), length of the knob pin, distance between the knob pin pivot(on the contact link) and contact link pivot. Hence after the toggle point the knob rotates automatically and stops on the housing in ON position. The same main spring provides the energy to pull back/rotate the moving contact during OFF operating and TRIP operation.

ON-OFF operation: The figure 4 shows the assembly in ON condition. During this operation, the knob is rotated in clock wise up to the Toggle point of the links (as explained in OFF-ON operation). After toggle point the contact link is pulled by the main spring, which in turn rotates the Knob through the knob pin and brings the moving contact, knob to OFF position as shown in figure 4.

LATCHING PHENOMENON: The figure 7 shows the latching area that consists of one end of U-pin, contact link and latch. The latching area on the latch has a circular profile with its center concentric with its mounting hold. In latched condition, the force will be such a way that it passes through the center of U-pin profile and the center of curvature of the latching area of the latch. Since reaction force is through the center of the latch there is no torque generated on the latch and it stays latched during ON and OFF operation.

TRIPPING OPERATION: The tripping operation occurs only during ON condition. The Figure 4 shows the ON condition where the movement of the U-pin is stopped by the latch. Trip signal is given to the latch i.e. the trip force is given to the latch which enables to rotate in clockwise rotation thereby the rigid connection between the contact link and U-pin has converted to sliding joint. Since the contact link is constantly pulled by the main spring in anti-clockwise direction the contact link rotates independent to knob and U-pin which can slide along the slot of the contact link. While contact link along with the moving contact opens, the knob which has spring load constantly acting on it brings knob to OFF position. This knob rotation to OFF position retracts the U-pin end connected to the contact link slot. Once it reaches the slot end the latch which is spring loaded rotates back in clockwise direction and latches the U-pin again. Now the entire mechanism has come to OFF position.

Here the tripping force will be multiple of the reaction force generated at the latching point and the co-efficient of friction between the latch and U-pin. In this way the tripping force is reduce to greater extent. Also the main spring location is positioned such a way that while opening the contacts will have higher opening velocity which increases the electrical life of the circuit breaker and the short circuit breaking capacity. Hence the basic function of the circuit breaker is achieved with lesser number of components.

[0038] Figure 8 shows the existing mechanism of the circuit breaker. The big and small latch components are shown in the figure 8. In the present invention these two latched are replaced with single component which is Latch (4).

[0039] Figure 9 shows the reaction force direction when the mechanism is turned from OFF to ON. Here the reaction force F reaction always acts at the pivot of the latch (4). This is due the circular profile on the latch (4), at the region where the U-pin (7) is in contact. This circular profile has the center lying at the pivot of the latch (4) which enables the force direction always passing through the pivot of the latch (4). The present invention is originated from the force directions of the mechanism. In order ensure zero torque on the latch without any additional components, the circular profile on the latch (4) is created. By this circular profile the line of action of force is always through the pivot of the latch (4).

[0040] In one implementation, the contact link may be used to hold the moving contact and guides the U-pin through the slot during tripping.

[0041] In one implementation, the latch (4) is responsible for latching the U-Pin during normal ON-OFF operation.

[0042] Accordingly, a circuit breaker having at least one knob (1), at least one contact link (2), at least one moving contact (3), at least one fixed contact (5), at least one mainspring (6), at least one support pin (8), and at least one spring mounting pin (9), the circuit breaker ensuring zero torque on a latch (4). The circuit breaker comprises a U-shaped pin (7) and a latch (4) having a circular profile with a center. The one end of the U-shaped pin (7) is coupled to the knob (1) and other end of the U-shaped pin (7) is configured to slide to at least one slot provided on the contact link (2). The latch (4) is coupled with the contact link (2) and is configured to rotate in anti-clockwise direction. The latch (4) is configured to restrict the sliding of the U-shaped pin (7) along the slot of the contact link (2) there by making a revolute joint, such that during latching, the circular profile enables a reaction force to act at a pivot of the latch (4) and the reaction force passes through a center of U-shaped pin and the center of curvature of a latching area of the latch (4) to ensure zero torque on the latch (4).

[0043] The illustrations of arrangements described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other arrangements will be apparent to those of skill in the art upon reviewing the above description. Other arrangements may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[0044] Thus, although specific arrangements have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific arrangement shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments and arrangements of the invention. Combinations of the above arrangements, and other arrangements not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.