FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Mechanism For Tripping And Resetting Arrangement In Circuit Breaker"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: Larsen & Toubro Limited
Electrical & Automation North Wing, Gate 7, Level 0, Powai Campus, Saki Vihar Road, 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.

Mechanism For Tripping And Resetting Arrangement In Circuit Breaker
Field of invention
The present invention relates to circuit breakers, and more particularly, to a tripping and resetting mechanism in a under-voltage or over-voltage accessory for circuit breaker.
Background of the invention
Circuit breakers are designed to make, break and carry current, one main function of circuit breakers is to provide protection against over load and short circuit currents, in many cases accessories are generally installed along with the circuit breaker such as under voltage and over voltage release to protect from fault detected in the system. In order for protection, it is necessary to break the current. In this is achieved by tripping the actuating mechanism by a release which is housed inside the breaker and accessories that detects fault and convert electrical energy to mechanical energy to break the current.
The magnetic release or solenoid generally has a plunger inside release housing and coil wound around the housing whenever fault is detected in the system the plunger is released and strikes on to the mechanism that trips the breaker and break the current, once the plunger is released to trip the mechanism during fault it is necessary to reset it back to the original position along with the trip actuating mechanism for next tripping operation.
US Patent No. 5670923 titled 'tripping device reset arrangement', discloses a breaker which trip during the over current fault detection by a trip actuator unit which releases

the plunger (39) that hits the protrusion (37a) of intermediate lever which rotates in anti-clockwise direction and intern strikes plunger(19) against bias
spring (35) by protrusion (37b) this plunger(19) will strike the trip latch(46) and breaks the current, during this the reset arm (23) that is connected to reset plate (29) via extension spring (31) rotates anti-clockwise direction which extends the spring (31), this extension will apply force on reset plate that rotates plate in anti-clockwise direction along the pivot pin (21), as a result the reset pin (40) on the reset plate will interfere with the intermediate lever (37) and rotates it in the clockwise direction along pivot (38), resetting the shift plunger (39) of the flux shifter unit (26) against compression spring (44) by protrusion on intermediate plate (37a) .The plunger (19) is reset by bias spring (35)that was compressed during tripping .
Further, the US Patent 6172584 titled 'Circuit Breaker Accessory Reset System' discloses an arrangement of the trip actuating mechanism which consist of a release (82) housing a plunger (84) which strikes the plunger link (120) during fault detection, this plunger link in mechanically cooperated with a reset drive (112) via side reset spring (142), the reset drive (112) is cooperated with the side link (132) via spring (60), all of which is pivot as same point by means of pivot pin (152). The plunger link (120) has a side interface latch (130) incorporated in it that latches the slide (86). During tripping the plunger hits the plunger link (120) which rotates counter-clockwise direction de-latches the slide, this slide has a actuator tab (96) which is adjacent to latch trip tab (50) of main breaker as slide de-latches it slides due to energy released by compression spring and trips the mechanism by means of actuator tab (96).
The resetting of tripping actuating mechanism is done by rotating the handle (18) beyond off position as shown in figure. The handle (18) is interconnected with operating handle yoke (26) that includes reset tab (32) which cooperates the accessory

via reset pin (70) present on hook portion of side link (138) as knob is rotated counter-clockwise the reset pin (70) rotates side link in clockwise direction and energize spring (60) this energy intern rotates reset drive (132) in clockwise direction, since side reset spring (142) has one arm on reset drive and other arm on plunger link as reset drive rotates it drives the plunge link in clockwise direction via side reset spring , the protrusion on plunger link (122) pushes the plunger (84) and reset it.
Furthermore, the US Patent No 4801907 titled 'Under-voltage release accessory for a circuit breaker interior' discloses under voltage mechanism which consist of a release coil (15) with plunger (16) biased with under voltage spring (17). The trip actuator plunger (18) is connected to plunger (15) via plate(31) that has an adjustable screw (33). Whenever fault is sensed the coil (15) will be insufficient to hold the plunger (16) against spring force (17)therefore the spring (17) extends and release the plunger (16) that intern moves the trip actuator plunger (18) in forward direction where trip button (19) displaces trip bar (40) and trips the breaker mechanism. After tripping resetting of plunger is done by a reset mechanism in which the handle skirt (28) will move in direction as in figure and interfere with the operating lever tab (21) of operating lever (22) which rotates in counter-clockwise this intern rotates reset lever (24) and trip lever(36) in counter-clockwise direction via connecting rod (22)that connects operating lever (22), reset lever (24) and trip lever (36). At the reset lever (24) a reset spring (13) is attached that interfere with the plunger (16) will have maximum force than the voltage spring (17) during resetting that resets back the plunger (16) and have less force than the voltage.
spring during tripping that causes voltage spring to move against reset spring force and trip the mechanism. This change of force in reset spring is done by changing the direction of line of action of force which is achieved by the rotation of reset lever (24) during tripping and resetting.

Object of the invention
An object of the invention is to provide a mechanism for tripping and resetting arrangement in under-voltage or over-voltage accessory for circuit breaker which drives a solenoid by an electronic circuit.
Another object of the present invention is to provide a mechanism for tripping and resetting arrangement in the circuit breaker which provides tripping and resetting of the breaker with less power and accessory.
Summary of the invention
Accordingly, the present invention provides A mechanism for tripping and resetting arrangement in a circuit breaker, the mechanism comprising:
housing having a knob, a pin, a lock-lever and a connecting link, the pin connecting the knob with the lock lever and the connecting link;
a moving contact connected to the connecting link, the moving contact capable of sliding along a slot in the housing;
a contact spring enabling the moving contact to detachably attach to a fixed contact, wherein the fixed contact is connected to an electronic circuit;
a solenoid having a plunger connected to the electronic circuit, wherein the plunger detects fault and send signal to the solenoid;
a pivot capable of latching the lock lever when rotated in clockwise direction and de-latching the lock lever when rotated in anti-clockwise direction;
a trip lever positioned near the pivot, the trip lever capable of rotating a flag; and
a reset lever connecting the solenoid plunger and the trip lever,

wherein the plunger strikes the reset lever upon detecting the fault thereby rotating the reset lever in clockwise direction, the reset lever thereafter rotates trip lever in anti-clockwise direction which in turn rotates the pivot in clockwise direction and de-latches the lock lever thereby tripping the device, and thereafter the flag is rotated in clockwise direction which interferes with a slider edge and remain stable in this position until next ON operation.
Brief description of drawings
Figures 1-3 illustrates perspective view of a tripping and resetting mechanism of a circuit breaker of the prior art.
Figure 4 illustrates a front view of a circuit breaker in OFF condition, according to the present invention:
Figure 5 illustrates a front view of a circuit breaker in ON condition, according to the present invention;
Figure 6 illustrates a front view of a circuit breaker in TRIP condition, according to the present invention; and
Figure 7 illustrates a front view of a circuit breaker in RESET condition, according to the present invention
Detailed description of the present invention
The foregoing objects of the 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.

Accordingly, the present invention provides a mechanism for tripping and resetting arrangements in the under-voltage or over-voltage accessory for circuit breaker which provides tripping and resetting of the breaker with less power and accessory. Further, a solenoid in the mechanism for tripping and resetting of the proposer accessory is operated by an electronic circuit.
Referring now to figure 4-7 there is shown a mechanism for tripping and resetting arrangements in the circuit breaker (hereinafter the 'CB (100)').
Figure 4 illustrates a front view of a circuit breaker (CB) in OFF condition, according to the present invention. The CB (100) includes a housing (1) which in turn houses a knob (2), pin (3), lock-lever (4), connecting link (5), pivot (6), clamp (7), moving contact (8), fixed contact (9), contact spring (10) , solenoid (11) , slider (12), reset lever (13) , trip lever(14) and flag(15) along with flag spring (15a) that produce torque in anti-clockwise direction.
In an embodiment, the pin (3) is U shaped pin which connects knob (2) with lock lever (4) and connecting link (5).
Further, the moving contact (8) slides along the slot in housing (1) and is connected to the connecting link (5) via the clamp (7) and rivet (not shown). In an embodiment, the clamp is U shaped clamp.
The pivot (6) latches or stabilizes the entire mechanism during ON condition of the CB (100) and de-latches when it is rotated in clockwise direction is housed in the left hand side of the knob (2) axis.

The solenoid (11) along with plunger (11a) is connected to an electronic circuit (not shown) which detects the fault in CB (100) and send signal to solenoid (11). The web of the slider (12a) is in contact with the moving contact (8) that slides along with the moving contact (8).
Further, the reset lever (13) is placed such that one end of the reset lever (13) touches the tip of solenoid plunger (11a) and other end with trip lever (14). Also, the trip lever (14) is placed such that there is a small clearance between the pivot (6) and tip of the L-shape (14a).
Specifically, just below the L-shape of trip lever (14) there is a protrusion that is in contact with the flag (15). The end of L-shape in trip lever (14a) is responsible for rotating the pivot (6) in clockwise direction and tripping the mechanism. The protrusion below L-shape in trip lever (14a) is responsible for rotating the flag (150) for indication purpose during tripping operation.
Referring now to figure 5 which illustrates a front view of the miniature circuit breaker (CB) in ON condition, according to the present invention. Specifically, during ON condition, the knob (2) is rotated in clockwise direction wherein the moving contact (8) slides towards right in the slot against contact spring (10). The contact spring (10) gets compressed and stores energy, pushing the slider (12) along with it and finally comes in contact with fixed contact (9). The reset lever (13), trip lever (14) and the flag(15) remains in same position as until the entire operation.
Referring now to figure 6, which illustrates a front perspective view of the miniature circuit breaker (100) (CB) in TRIP condition, according to the present invention. During the trip condition, the electronic circuit (not shown) detects the fault and send signal to solenoid or magnetic release (11) which convert electrical energy to mechanical energy by releasing plunger (1 la).The plunger (11a) strikes the reset lever

(13) and as a result the reset lever (13) rotates in clockwise direction thereby rotating the trip lever (14) in anti-clockwise direction. Further, the tip of L-shape in trip lever (14a) hits the pivot (6) and rotates the pivot (6) in clockwise direction which de-latches the lock lever (4) and trips the mechanism. During the tripping operation of the MCB (100), protrusion below L-shape lever (14) rotates the flag (15) in clockwise direction against flag spring(15a) torque.
Referring now to figure 7, which represent a front perspective view of a front perspective view of the miniature circuit breaker (100) (CB) in RESET condition. After tripping of the CB (100), the moving contact (8) along with the slider (12) slides towards left by means of the energy released by the contact spring (10). During this, the protrusion on the slider (12b) come in contact with the trip lever (13).
As the slider (12) is moving in linear direction, the protrusion on slider (12b) applies force on the trip lever (14) that rotates the trip lever (14) in clockwise direction. Thereafter, the trip lever (14) rotates the reset lever (13) in anti-clockwise direction. The tip of the reset lever (13) is in contact with the plunger (11a) and push the solenoid plunger (11a) back inside solenoid housing (11). Accordingly, the plunger (11a) and the trip actuating mechanism reset for complete travel of slider (12). Further, the flag (15) which was rotated in clockwise direction against flag spring (15a) interferes with the slider edge (12c) and remain stable in this position until next ON operation where the flag (15) reset by means of flag spring (15a).
Advantages of the invention
1. The mechanism provides a unique trip actuating mechanism for tripping and resetting the mechanism by utilization of contact spring to achieve both contact velocity and resetting of mechanism.

2. The tripping element used in the mechanism such as magnetic release or
solenoid is driven through electronic circuit.
3. The mechanism may be used for overvoltage release, under voltage release, shunt or any kind of accessory which is driven through electric faults.
4. The permanent magnet relay (PMR) can be used instead of solenoid or magnetic release to consume less power.
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 mechanism for tripping and resetting arrangement in a circuit breaker (CB), the mechanism comprising:
housing having a knob, a pin, a lock-lever and a connecting link, the pin connecting the knob with the lock lever and the connecting link;
a moving contact connected to the connecting link, the moving contact capable of sliding along a slot in the housing;
a contact spring enabling the moving contact to detachably attach to a fixed contact, wherein the fixed contact is connected to an electronic circuit;
a solenoid having a plunger connected to the electronic circuit, wherein the plunger detects fault and send signal to the solenoid;
a pivot capable of latching the lock lever when rotated in clockwise direction and de-latching the lock lever when rotated in anti-clockwise direction;
a trip lever positioned near the pivot, the trip lever capable of rotating a flag; and
a reset lever connecting the solenoid plunger and the trip lever,
wherein the plunger strikes the reset lever upon detecting the fault thereby rotating the reset lever in clockwise direction, the reset lever thereafter rotates trip lever in anti-clockwise direction which in turn rotates the pivot in clockwise direction and de-latches the lock lever thereby tripping the device, and thereafter the flag is rotated in clockwise direction which interferes with a slider edge and remain stable in this position until next ON operation.
2. The mechanism as claimed in claim 1, the moving contact is connected to the connecting link through a clamp and a rivet.

3. The mechanism as claimed in claim 1, wherein the moving contact slides in the slot against the contact spring thereby pushing the slider and making contact with a fixed contact.
4. The mechanism as claimed in claim 1, wherein the flag is provided for indication during tripping operation, the flag having a spring for resetting thereof.