FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
GENERAL MECHANISM FOR CIRCUIT BREAKERS;
LARSEN & TOUBRO LIMITED, A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS L&T HOUSE, BALLARD ESTATE, MUMBAI - 400 001, MAHARASHTRA, INDIA
THE FOLLOWING SPECIFICATION
PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

Field of the Invention
The invention relates generally relates to Moulded Case Circuit Breakers (MCCB). More particularly, the present invention relates to an automatic tripping mechanism.
Background of the invention
Generally, circuit Breaker is well known in the art which is a mechanical switching device capable of making, carrying and breaking currents. The mechanism of the circuit breaker plays a vital role in determining the credibility of the breaker. A good mechanism should ensure quick and manually independent opening and closing of contact system. Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.
In conventional type MCCBs, breaker will feature three positions in the top cover near the knob to show ON, OFF and TRIP. Here first two operations are initiated by operator whereas the trip signal is given by the release which senses the abnormal conditions and gives TRIP command to the mechanism, so that the latter opens the circuit.

The operator has access to the mechanism through the knob which will be projected outwards from the housing of the breaker. The knob is placed over the fork of the operating mechanism.
When the knob indicates ON it means the breaker is in ON condition i.e., the current path is closed with the assist of upper link, and the stopper pins. Similarly the position of the knob indicates the state of the circuit breaker.
According to standards, the top position of the knob (if the breaker is placed vertically) or the longest distant position of the knob away from the operator (if the breaker is mounted horizontally) should be marked as ON POSITION. The other extreme end in both cases is marked as the OFF POSITION. The knob exist somewhere near the centre (based on the design of the mechanism) to indicate the TRIP POSITION.
As said above, TRIP command is given automatically to the contacts by the release if it senses an abnormal condition like overload and short circuit. If the trip signal is given, the breaker opens the circuit and the knob goes to the trip position to show the operator that a fault has occurred in the system.
Presently the circuit breaker uses the large number of brooches to do the above mentioned operations. Here tlowerhe rivet pin is the one which is used to connect the two upper limbs in order to make them stiff and there is a spring shaft for mounting the springs.
Further the present breaker uses the separate pin for mounting biasing spring and it utilizes some additional stopper pins to arrest the rotation mechanism of the above mentioned conditions(ON, OFF, TRIP).

Further if the operator wants to switch ON the breaker after the breaker is tripped, he/she cannot do it without resetting the breaker. This is to make sure that the operator shouldn't switch ON the breaker before clearing the fault. Resetting of the breaker is done by moving the knob (fork) towards the OFF position from the TRIP position. This movement loads the mechanism spring and now it is possible for the operator to ON the breaker. All these mechanisms are called semi-automatic mechanisms since for ON and OFF operation, and it is more reliant to the operators and it uses large number of pins and components.
Therefore, there is a need in the art which overcomes the above mentioned problems and completes the operation of circuit breaker automatically.
Summary of the Invention
An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below.
Accordingly, an aspect of the present invention is an automatic tripping mechanism arrangement in a moulded case circuit breaker, the arrangement comprising: a fork, the fork mounted on a plurality of mounting plates by a fork hinge pin, wherein the mounting plates includes a first profile (d) which facilitates mounting of one end of biasing spring, a trip lever is hinged to the mounting plates by trip lever pin, a plurality of upper links are coupled separately to each side of the trip lever with the help of an UL pin, wherein a Limb (a) is placed intermediately between the upper links for mounting main springs and to make

rigid the upper links and a trip plate includes a second profile (e) which facilitates mounting of other end of biasing spring, during trip condition the rotation of mechanism is arrested by providing a third profile (b) in trip lever, where the trip plate holds the trip lever using a trip latch.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
Brief description of the 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:
Figure 1 shows the isometric view of mechanism with cassette according to one embodiment of the present invention.
Figure 2 shows the exploded view of mechanism of circuit breaker according to one embodiment of the present invention.
Figure 3 shows the circuit breaker in ON position according to one embodiment of the present invention.
Figure 4 shows the circuit breaker in OFF/RESET position according to one embodiment of the present invention.

Figure 5 shows the circuit breaker in TRIP position according to one embodiment of the present invention.
Figure 6 shows the circuit breaker in TRIP FREE position according to one embodiment of the present invention.
Figure 7 shows the upper link is made unique by limb according to one embodiment of the present invention.
Figure 8 shows the mounting of the biasing spring according to one embodiment of the present invention.
Figure 9 shows the mechanism of the Moulded Case Circuit Breakers (MCCB) according to one embodiment of the present invention.
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.
Detail description of the invention
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.
Figure 1 shows the isometric view of mechanism with cassette according to one embodiment of the present invention.
Figure 2 shows the exploded view of mechanism of circuit breaker according to one embodiment of the present invention.
Figure 3 shows the circuit breaker in ON position according to one embodiment of the present invention. The current invention has a fork 3, which is mounted on the mounting plates 4. The upper links 2 are connected separately to each side of the trip lever 11 with the help of UL pin 22. The orientation and position of the upper links 2 and lower links 5 are maintained by the presence of UL_LL pin 23. The lower links 5 are connected to the connecting link 8 by using

LL_CL pin 20The connecting link 8 is connected to the mounting plates 4 by using the coupling pin 25. The drive shaft pin 9 is used to connect the connecting link 8 and cassette rotor shaft. The mainsprings are connected between the fork 3 and spring pin 7 through which the transmission of energy occurs from fork 3 to the drive shaft Pin 9. The upper links 2 and the lower links 5 which performs the operations meant for an MCCB through connecting link 8. The connecting link 8 which in turn rotates the cassette accordingly by make a use of drive shaft pin 9. And the trip plate 16 will be holding the trip latch 15 in the ON condition.
In this position, the fork will be in the position far away from the trip system to point out the ON position. The upper links 2, lower links 5 and connecting link 8 will be holding the contacts in the closed circuit condition with the help of the drive shaft pin 9.
Figure 4 shows the circuit breaker in OFF/RESET position according to one embodiment of the present invention.The current invention has a fork 3, which is mounted on the mounting plates 4. The reset pin 21 is used to stop the fork in the trip position and to reset the mechanism back to the OFF position. The upper links 2 are connected separately to each side of the trip lever 11 with the help of UL pin 22. The orientation and position of the upper links 2 and lower links 5 are maintained by the presence of UL_LL pin 23. The lower links 5 are connected to the connecting link 8 by using LL_CL pin 20The connecting link 8 is connected to the mounting plates 4 by using the coupling pin 25. The drive shaft pin 9 is used to connect the connecting link 8 and cassette rotor shaft. The mainsprings are connected between the fork 3 and spring pin 7 through which the transmission of energy occurs from fork 3 to the drive shaft Pin 9. The upper

links 2 and the lower links 5 which performs the operations meant for an MCCB through connecting link 8. The connecting link 8 which in turn rotates the cassette accordingly by make a use of drive shaft pin 9.
In this position, the fork will be in the position very near to the trip system thus indicates the OFF position. The upper links 2, lower links 5 and connecting link 8 will be holding the contacts in the open circuit condition with the help of the drive shaft pin 9. And the trip plate 16 will be holding the trip latch 15 in the OFF condition
Figure 5 shows the circuit breaker in TRIP position according to one embodiment of the present invention. The components trip latch pin 13, trip plate pin 14, trip latch 15 & trip plate 16 comprises of the trip system. The current invention has a fork 3, which is mounted on the mounting plates 4. The trip lever 11 is hinged to the mounting plates 4 with the help of trip lever pin 10. The upper links 2 are connected separately to each side of the trip lever 11 with the help of UL pin 22. The orientation and position of the upper links 2 and lower links 5 are maintained by the presence of UL_LL pin 23. The lower links 5 are connected to the connecting link 8 by using LL_CL pin 20.The connecting link 8 is connected to the mounting plates 4 by using the coupling pin 25. The drive shaft pin 9 is used to connect the connecting link 8 and cassette rotor shaft. The mainsprings are connected between the fork 3 and spring pin 7 through which the transmission of energy occurs from fork 3 to the drive shaft Pin 9. The upper links 2 and the lower links 5 which performs the operations meant for an MCCB through connecting link 8. The connecting link 8 which in turn rotates the cassette accordingly by make a use of drive shaft pin 9.

The trip latch 15 will be holding the trip lever 11 in its original position in ON and OFF position. And the trip plate 16 will be holding the trip latch 15 in the ON & OFF conditions. During trip & trip free operations the trip signal will be given to the trip plate 16 and as a result, the trip latch 15 is released enabling the trip lever to rotate about its pivot point.
In this position, the fork 3 will be in the position anywhere between the ON & OFF positions and the position is constrained by the rotation of trip lever 11. The Reset pin 21 stops the trip lever 11 from further rotation. And the contacts will be in the opened condition.
Figure 6 shows the circuit breaker in TRIP FREE position according to one embodiment of the present invention.The components trip latch pin 13, trip plate pin 14, trip latch 15 & trip plate 16 comprises of the trip system. In TRIP FREE position there is an unstable position for the fork 3, as the knob will be held in the knobs ON position by the operator.
Figure 7 shows the upper link is made unique by limb according to one embodiment of the present invention. The Upper link (2) is made unique by providing the limb which is used for mounting main springs & to make the upper link rigid without the usage of any rivet.
Figure 8 shows the mounting of the biasing spring according to one embodiment of the present invention. Biasing spring mounting can be made easier by the mounting plates (4) & profile (e) in trip plate (16). The spring is the one which opens/closes the contact system.

Figure 9 shows the mechanism of the circuit breaker according to one embodiment of the present invention. The rotation of mechanism in trip condition is arrested by providing the profile (b) in the trip lever (11) which hit the mounting plate spacer (1). Here, lower link(5) & connecting link(8) are connected using LL-CL pin(20), which acts as a stopper for mechanism rotation in OFF and TRIP condition by hitting the profile(c) given in the mounting plates.
In one example embodiment an automatic tripping mechanism arrangement in a moulded case circuit breaker includes a fork, the fork mounted on a plurality of mounting plates by a fork hinge pin, where the mounting plates includes a first profile (d) which facilitates mounting of one end of biasing spring, a trip lever is hinged to the mounting plates by trip lever pin, a plurality of upper links are coupled separately to each side of the trip lever with the help of an UL pin, where a Limb (a) is placed intermediately between the upper links for mounting main springs and to make rigid the upper links. The upper links orientation and position are maintained by UL_LL pin with lower links. The lower links are coupled to one end of a connecting link by using LL_CL pin, where other end of the connecting link is connected to the mounting plates by using a coupling pin (c). The upper links, lower links, and connecting links holding the contacts in open/closed circuit condition with the assist of drive shaft pin. A trip plate includes a second profile (e) which facilitates mounting of other end of biasing spring, during trip condition the rotation of mechanism is arrested by providing a third profile (b) in trip lever, where the trip plate holds the trip lever using a trip latch.

The arrangement further including a drive shaft pin is used to connect the connecting link and cassette rotor shaft. Further the arrangement includes a main springs connected between the fork and a spring pin through which the transmission of energy occurs from fork to the drive shaft pin.
Although the invention has been described in terms of preferred embodiment, it is not limited thereto. Those skilled in this technology can make various alterations and modifications without departing from the scope and spirit of the invention. Therefore, the scope of the invention shall be defined and protected by the following claims and their equivalents.
FIGS. 1-9 are merely representational and are not drawn to scale. Certain portions thereof may be exaggerated, while others may be minimized. FIGS. 1-9 illustrate various embodiments of the invention that can be understood and appropriately carried out by those of ordinary skill in the art.

We Claim:
1. An automatic tripping mechanism arrangement in a moulded case circuit
breaker, the arrangement comprising;
a fork;
the fork mounted on a plurality of mounting plates by a fork hinge pin, wherein the mounting plates includes a first profile (d) which facilitates mounting of one end of biasing spring;
a trip lever is hinged to the mounting plates by trip lever pin;
a plurality of upper links are coupled separately to each side of the trip lever with the help of an UL pin, wherein a Limb (a) is placed intermediately between the upper links for mounting main springs and to make rigid the upper links; and
a trip plate includes a second profile (e) which facilitates mounting of other end of biasing spring, during trip condition the rotation of mechanism is arrested by providing a third profile (b) in trip lever, where the trip plate holds the trip lever using a trip latch.
2. The arrangement as claimed in claim 1, wherein the upper links orientation and position are maintained by ULJ_L pin with lower links.
3. The arrangement as claimed in claim 2, wherein the lower links are coupled to one end of a connecting link by using LL_CL pin, wherein other end of the connecting link is connected to the mounting plates by using a coupling pin (c).

4. The arrangement as claimed in claim 1, further comprising:
a drive shaft pin is used to connect the connecting link and cassette rotor shaft.
5. The arrangement as claimed in claim 1, further comprising:
a main springs connected between the fork and a spring pin through which the transmission of energy occurs from fork to the drive shaft pin.
6. The arrangement as claimed in claim 1-5, wherein the upper links, lower
links, and connecting links holding the contacts in open/closed circuit condition
with the assist of drive shaft pin.