CLIAMS:1. A contact system with a toggle mechanism, the system comprising:
a driveshaft (1);
an extension spring (2);
a toggle link (3);
a floating pin (4);
an upper moving contact (5) with a slot;
a contact pin (7);
a toggle link pivot pin (8); and
a spring pin (9)
wherein
the upper moving contact (5) is assembled in the driveshaft (1) using the contact pin (7) having the toggle link pivot pin (8).

2. The contact system of claim 1, further comprising an upper moving contact button (6).

3. The contact system of claim 1, wherein the toggle link (3) is assembled in the driveshaft (1).

4. The contact system of claim 1, wherein the extension spring (2) is connected between the spring pin (9) and the toggle link (3).

5. The contact system of claim 1, wherein the upper moving contact (5) is engaged with the toggle link (3) by means of the floating pin (4).

6. The contact system of claim 1, wherein the floating point (4) slide in the slot.
,TagSPECI:TECHNICAL FIELD

The present subject matter described herein, in general relates to a circuit breaker and more particularly, to a moving contact which is assembled with another moving insulating member called driveshaft by means of a toggle mechanism.

BACKGROUND

In general a circuit breaker or a moulded case circuit breaker (MCCB) is used in an electrical power distribution circuit of a building, a factory, a ship or so as to switch off and switch on a normal circuit and automatically break the circuit during a fault condition.
The moving contact system of MCCB comprises of the driveshaft , the moving contact, connecting rod, , extension spring, positioning axis such composition,. During a short circuit fault the high current flows through the current path of the circuit breaker. Due to high current the moving contact experiences a repulsion force due to electromagnetic forces. The moving contact opens and breaks the circuit. This phenomenon helps the circuit breaker to limit the current and let through energy. In this case, the mechanism should open the driveshaft before reclosing of the contacts.

Further, in the prior art circuit breakers, the moving (upper) contact is assembled to the driveshaft along with a spring. The moving contact repels during short circuit fault and breaks the circuit. In these cases, the mechanism should open before the moving contact recloses. Reclosing of the moving contact leads to re-strike and resulting higher fault clearing time, higher let through energy.
So there exists a need to provide an improved contact system with contact locking mechanism of the moulded case circuit breaker.

SUMMARY

This summary is provided to introduce concepts related to an improved circuit breaking technique for circuit breaker. This summary is not intended to identify essential features of the subject matter nor is it intended for use in determining or limiting the scope of the subject matter.

In one implementation, an improved contact system with contact locking mechanism of a Moulded Case Circuit Breaker (MCCB) is disclosed.

In one implementation, the moving (upper) contact is assembled in driveshaft with the help of toggle link, spring and pins. The moving contact is assembled with driveshaft by means of a pin. The moving contact is engaged with the rotatable toggle link in such a way that the toggle link rotates whenever the contact rotates. An extension spring is assembled between toggle link and a pin attached to drive shaft.

In one implementation, the toggle mechanism locks the moving contact in repelled position & prevents the moving contact from reclosing. The moving contact comes back to its original position as soon as the driveshaft comes to open position.

In one implementation, the invention provides an early fault clearing mechanism, and further the contact locking feature also works as backup protection to the mechanism and release failure. So, this contact locking feature provides extra protection to the circuit.

In one implementation, an improved contact system with contact locking mechanism of the moulded case circuit breaker (MCCB) is disclosed. The contact system comprises of a driveshaft (1), an extension spring (2), a toggle link (3), a floating pin (4), an upper moving contact (5) with a slot, a contact pin (7), a toggle link pivot pin (8); and a spring pin (9). The upper moving contact (5) is assembled in the driveshaft (1) using the contact pin (7) having the toggle link pivot pin (8).

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

Figure 1 illustrates an isometric view of contact system is shown, in accordance with an embodiment of the present subject matter.

Figure 2 illustrates a sectional isometric view of contact system is shown, in accordance with an embodiment of the present subject matter.

Figure 3 illustrates a sectional view of contact system in normal condition is shown, in accordance with an embodiment of the present subject matter.

Figure 4 illustrates a sectional view of contact system at the moment of toggling is shown, in accordance with an embodiment of the present subject matter.

Figure 5 illustrates a sectional view of contact system in contact locked condition is shown, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION

Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

The present invention can be applied to both single-break circuit breakers, can be applied to double-break circuit breaker, and can also be applied to the composition of the multiple contacts of the circuit breaker the moving contacts.

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. 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.

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.

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

Accordingly, present invention an improved contact system with contact locking mechanism of the moulded case circuit breaker (MCCB).

Construction of the contact system of the present invention is explained with reference to the accompanying figures.

List of components:

1. Driveshaft (1)
2. Extension spring (2)
3. Toggle link (3)
4. Floating pin (4)
5. Upper moving contact (5)
6. Upper moving contact button (6)
7. Contact pin (7)
8. Toggle link pivot pin (8)
9. Spring pin (9)

In one implementation, an improved contact system with contact locking mechanism of the moulded case circuit breaker (MCCB) is disclosed. The contact system comprises of a driveshaft (1), an extension spring (2), a toggle link (3), a floating pin (4), an upper moving contact (5) with a slot, a contact pin (7), a toggle link pivot pin (8); and a spring pin (9). The upper moving contact (5) is assembled in the driveshaft (1) using the contact pin (7) having the toggle link pivot pin (8).

The present invention relates to an improved contact system with contact locking feature of a moulded case circuit breaker. The prime feature of present invention is to achieve the contact locking by means of a toggling mechanism.

The present invention provides an improved contact system by addition of contact locking feature using a toggle mechanism as shown in figures. The upper moving contact (5) is assembled in the driveshaft (1) with the help of a pin called contact pin (7) as shown in figure 1 and figure 2. With the toggle link pivot pin (8) as the center, the toggle link (1) is assembled in the driveshaft (1) for its free rotation. One extension spring (2) is connected between the fixed spring pin (9) and the toggle link (3). The upper moving contact (5) is engaged with the toggle link (3) by means of a pin called floating pin (4). A slot is provided in the upper moving contact (5). The floating pin (4) slides in that given slot during rotation of the moving contact (5).

In this toggle mechanism the main feature toggling is provided by the toggle link (3) and the extension spring (2). The toggling procedure is explained in three steps as shown in figure 3, figure 4, and figure 5.

Referring now to figure 1, an isometric view of contact system is shown, in accordance with an embodiment of the present subject matter.

In one example, the figure 1 shows the normal condition of the contact system. In this condition due to extension spring (2) force the toggle link (3) experiences a torque in clock wise direction. This force is transferred to moving contact (5) through the floating pin (4). The transferred force generates a torque on the upper moving contact (5) in the anti clock wise direction and provides contact pressure. If a force is applied on the upper moving contact button (6) or upper moving contact (5) in upward direction, the upper moving contact (5) will experience another torque in clock wise direction. If the clock wise directional torque is higher than that of the anti-clock one produced due to the extension spring (2), the upper moving contact (5) will start rotating in clock wise direction and the toggle link (3) will be rotating anti-clock wise. After sufficient rotation the extension spring (2) axis will be aligned with the toggle link (3) axis as shown in figure 4.

This is called as dead centre. A slight rotation after that will change the direction of the spring force on the toggle link (3) and the torque on the toggle link(3) is reversed to anti-clock one. Due to this the toggle link (3) continues to rotate in anti-clock wise direction and the upper moving contact (5) in clock wise direction. The moving contact stops at certain position and stays there due to spring force as shown in figure 5. This is known as contact locked condition.

During short circuit fault a high current flow through the current path of the circuit breaker. Due to high current the upper moving contact (5) experiences a repulsion force due to electromagnetic forces. The upper moving contact (5) starts opening (rotating in clock wise direction) and breaks the circuit. The mechanism stays at final position after the toggling and prevents the upper moving contact (5) from re-closing. This phenomenon helps the circuit breaker to limit the current, let through energy and avoids re-strike.

Referring now to figure 2, a sectional isometric view of contact system is shown, in accordance with an embodiment of the present subject matter.

In one example, the figure 2 shows, the toggle link pivot pin (8) as the center, the toggle link (1) is assembled in the driveshaft (1) for its free rotation. One extension spring (2) is connected between the fixed spring pin (9) and the toggle link (3). The upper moving contact (5) is engaged with the toggle link (3) by means of a pin called floating pin (4). A slot is provided in the upper moving contact (5). The floating pin (4) slides in that given slot during rotation of the moving contact (5).

Referring now to figure 3 and figure 4, a sectional view of contact system in normal condition, and a sectional view of contact system at the moment of toggling, respectively is shown, in accordance with an embodiment of the present subject matter

In figure 3, a normal condition working of the system is explained. It works in the similar manner as explained in the working of figure 1.

In figure 4, if a force is applied on the upper moving contact button (6) or upper moving contact (5) in upward direction, the upper moving contact (5) will experience another torque in clock wise direction. If the clock wise directional torque is higher than that of the anti-clock one produced due to the extension spring (2), the upper moving contact (5) will start rotating in clock wise direction and the toggle link (3) will be rotating anti-clock wise. After sufficient rotation the extension spring (2) axis will be aligned with the toggle link (3) axis as shown in figure 4.

This is called as dead centre. A slight rotation after that will change the direction of the spring force on the toggle link (3) and the torque on the toggle link(3) is reversed to anti-clock one. Due to this the toggle link (3) continues to rotate in anti-clock wise direction and the upper moving contact (5) in clock wise direction.

Referring now to figure 5 illustrates a sectional view of contact system in contact locked condition is shown, in accordance with an embodiment of the present subject matter.

In one example, the moving contact stops at certain position and stays there due to spring force as shown in figure 5. This is known as contact locked condition.

During short circuit fault a high current flow through the current path of the circuit breaker. Due to high current the upper moving contact (5) experiences a repulsion force due to electromagnetic forces. The upper moving contact (5) starts opening (rotating in clock wise direction) and breaks the circuit. The mechanism stays at final position after the toggling and prevents the upper moving contact (5) from re-closing. This phenomenon helps the circuit breaker to limit the current, let through energy and avoids re-strike.

Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features:

One feature of the invention is that, it performs the contact locking by means of toggling mechanism

Another feature of the invention is that, the toggle link toggles and locks the moving contact in its final position.

Another feature of the invention is that, the toggle link can toggles with the help of spring in absence of moving contact independently.

Another feature of the invention is that, the present invention helps to clear the fault with less time.

Another feature of the invention is that, the contact locking eliminates the chances of contact re-closing and re-strikes.

Yet another feature of the invention is that, the reduction in let through is achieved due to lesser fault clearing time. This leads to lesser stress on downstream devices.

Although implementations for the improved contact system by addition of contact locking feature using a toggle mechanism have been described in language specific to structural features and/or the methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features are disclosed as examples of an improved contact system by addition of contact locking feature using a toggle mechanism.

It is intended that the disclosure and examples above be considered as exemplary only, with a true scope and spirit of disclosed embodiments being indicated by the following claims.