Claims:We claim:

1. A position indicating mechanism for withdrawable circuit breaker, the position indicating mechanism comprising:
an slider/actuator mounted on a base plate of a side plate of the circuit breaker, the slider/actuator configured to a have a semicircular portion and a pip extending outward;
a guide pin is inserted through a hole of upwardly bent surfaces of the base plate such that the guide pin lie in the semicircular portion of the slider/actuator;
a retention spring inserted into the guide pin and rested on the slider/actuator and the upwardly bent surface of the base plate;
a split pin for locking the slider/actuator, the guide pin and retention spring in between the upwardly bent surfaces of the base plate;
a plurality of microswitches fixed to in the base plate; and
a connector block for terminating electrical connections from the plurality of microswitches, wherein the connector block configured to accessed by user from the left side cover of the circuit breaker,
wherein upon racking of the circuit breaker into a cradle, the slider/actuator is pushed by a slot in the back plate left of the circuit breaker, thereby moving the slider/actuator in parallel to the guide pin opposing the force offered by the retention spring and a pip of the slider/actuator to actuates the corresponding microswitch of the plurality of microswitches thereby indicating position of circuit breaker.

2. The position indicating mechanism as claimed in claim 1, wherein the retention spring push the slider/actuator back against the back plate while racking out the circuit breaker from the cradle, not allowing the slider/actuator to go to its end position completely, thereby indicating position of circuit breaker while racking.

3. The position indicating mechanism as claimed in claim 1, wherein the plurality of microswitches are fixed to in the base using screw nut or rivets.

, Description:Field of the invention

The present invention relates to a withdrawable circuit breaker, and more particularly, the present invention relates to withdrawable-unit with a mechanism to synchronously indicate location of the circuit breakers’ three distinct position viz. connected, test and disconnected.

Background of the invention

Withdrawable unit (Draw-out module) is an arrangement which is used to connect a circuit breaker to a main power source without unbolting or disturbing termination. This is done with the help of a mechanism wherein the operator can rack in or out the circuit breaker to or from a cradle. The cradle is a part of the draw-out module which has a jaw type spring contacts that is connected to the power source. When the circuit breaker is racked in, the plugs in the circuit breaker engages with socket (jaw contacts) in the cradle thus establishing a removable joint with the source.

Generally, there are two types of supplies in a switchboard. One is a main supply used to power the loads via the circuit breaker and other is an auxiliary supply used for auxiliaries like shunt release, UV release, and the like. Accordingly, the draw-out can be used in three different positions in order to use/test these poser sources, they are ‘DISCONNECTED’ (both Aux. connections and power connections not connected) ‘TEST’ (Aux. connections only connected but not power supply) and ‘CONNECTED’ (both Aux. connections and power connections are connected).

In order to indicate the position of the circuit breaker (disconnected, test and disconnected), a common method of indication is electrical and mechanical indication. For both these indication, the input can be taken from the circuit breaker or the draw out mechanism. The mechanical indication is indicated through an indicator, in case of electrical indication the output can be taken from a connector block and it can be used for displaying the location using a light source, or create a logic circuit.

The prior art mechanism of position indication for the circuit breaker has following disadvantages.
1. Tilting of circuit breaker causes error in indication.
2. True indication of the circuit breaker position not possible when the input is taken from the mechanism.
3. Electrical indication given as an add-on accessory can create issues when the user assembles it.

Accordingly, there exists a need to provide a position indicating mechanism for withdrawable circuit breaker, which overcomes abovementioned drawbacks.

Objects of the invention

An object of the present invention is to provide true indication of position of circuit breaker.

Another object of the present invention is to provide position indication mechanism for the circuit breaker in which tilting of the breaker has lesser effect.

Yet another object of the present invention to indicate “n” number of positions of a withdrawable circuit breaker.

Summary of the invention

Accordingly, the present invention provides a position indicating mechanism for withdrawable circuit breaker. The position indicating mechanism comprises a slider/actuator mounted on a base plate of a side plate of the circuit breaker. The slider/actuator is configured to a have a semicircular portion and a pip extending outward. Further, the position indicating mechanism comprises a guide pin inserted through a hole of upwardly bent ends of the base plate such that the guide pin lie in the semicircular portion of the slider/actuator. Furthermore, the position indicating mechanism comprises a retention spring inserted into the guide pin and rested on the slider/actuator and the upwardly bent ends of the base plate, and a split pin for locking the slider/actuator, the guide pin and retention spring in between the upwardly bent surfaces of the base plate. The position indicating mechanism also comprises a plurality of microswitches fixed to in the base plate and a connector block for terminating electrical connections from the plurality of microswitches. In an embodiment, the connector block is configured to be accessed by user from the left side cover of the circuit breaker.

Upon racking of the circuit breaker into a cradle, the slider/actuator is pushed by a slot in the back plate left of the circuit breaker, thereby moving the actuator in parallel to the guide pin opposing the force offered by the retention spring. A pip of the slider/actuator actuates the corresponding microswitch of the plurality of microswitches thereby indicating position of circuit breaker.

Brief description of the drawings

Figure 1 shows withdrawable circuit breaker at Rack-in condition i.e. in connected condition;

Figure 2 shows withdrawable circuit breaker at Rack-out condition;

Figure 3 shows the withdrawable circuit breaker;

Figure 4 a slider/actuating mechanism of a position indicating mechanism, in accordance with the present invention;

Figure 5 shows a slider/actuator based electrical indication of the position indicating mechanism in accordance with the present invention; and

Figure 6 shows input of slider/actuator based indication of the position indicating mechanism.

Detailed 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 embodiment.

The present invention provides a position indicating mechanism for withdrawable circuit breaker. The position indicating mechanism provides true indication of position of circuit breaker. Further, the position indicating mechanism provides position indication mechanism for circuit breaker in which tilting of the breaker has lesser effect. Also, the position indicating mechanism indicates “n” number of positions of a withdrawable circuit breaker.

Referring to figure 1-6, there is shown a position indicating mechanism (hereafter “the mechanism (100)”) for withdrawable circuit breaker (200), in accordance with the present invention. The mechanism (100) comprises a slider/actuator (10), a guide pin (20), a spring (30), a split pin (40), a plurality of microswitches (50) and a connector block (60).

The slider/actuator (10) is mounted on a base plate (112) of a side plate (110) of the circuit breaker (200). The slider/actuator (10) is configured to a have a semicircular portion and a pip (12) extending outward. The base plate (112) includes two ends upwardly bent to form a bracket like structure. Each upwardly bent end of the base plate (112) includes at least one hole configured thereon.

The guide pin (20) is inserted through the hole of upwardly bent ends of the base plate (112) such that the guide pin (20) lies in the semicircular portion of the slider/actuator (10).

Further, the spring (30) also know as retention spring (30) is inserted into the guide pin (20) and rested on the slider/actuator (20) and the upwardly bent surface of the base plate (112).

The split pin (40) is used for locking the actuator (10), the guide pin (20) and retention spring (30) in between the upwardly bent ends of the base plate (112) as shown in figure 4.

The plurality of microswitches (50) are also fixed to in the base plate (112). In an embodiment, the plurality of microswitches (50) are fixed to in the base plate (112) using screw nut or rivets.

The connector block (60) is provided in the mechanism (100) for terminating electrical connections from the plurality of microswitches (50). In preferred embodiment, the connector block (60) is configured to be accessed by user from the left side cover (120) of the circuit breaker (200).

Upon racking of the circuit breaker (200) into a cradle, the slider/actuator (10) is pushed by a slot (13) in the back plate left of the circuit breaker (200). This moves the slider/actuator (10) in parallel to the guide pin (20) opposing the force offered by the retention spring (30). As the slider/actuator (10) moves, the pip (12) of the slider/actuator (10) moves to actuate the corresponding microswitch of the plurality of microswitches (50) thereby indicating position of the circuit breaker. As the circuit breaker (200) moves from one position to another, the slider/actuator (10) moves along with the circuit breaker (200) and the corresponding microswitch of the plurality of microswitches (50) is actuated, thus completing the electrical circuit.

In an embodiment, by increasing or decreasing width of the pip (12), the time band for each actuation can be increased or decreased. Further, both the top and bottom surface of the slider/actuator (10) can be used to actuate the plurality of microswitches (50) which results in increased number or output for the given space. Specifically, auxiliary switches can also be mounted vertically to utilize the space. In an embodiment, the mechanism (100) can be made long to increase the number of output.

Further, when the retention spring (30) push the slider/actuator (10) back against the back plate (112) while racking out the circuit breaker (200) from the cradle, the back plate (112) does not allows slider/actuator (10) go to its end position completely, thereby indicating position of circuit breaker while racking.

Advantages of the invention

1. The mechanism (100) allows the indication at “n” number of positions of the withdrawable circuit breaker.

2. In the mechanism (100), input for indication is taken from the circuit breaker hence true position of the circuit breaker is obtained.

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, and 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 omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.