F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See section 10; rule 13)
1.Title of the invention: A DEVICE FOR USE IN CIRCUIT BREAKERS
2. Applicant(s):
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : L & T House, Ballard Estate, Mumbai
400 001,State of Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The followng specification particularly describes the invention and the manner in which it is to be performed:

TECHNICAL FIELD OF THE INVENTION
This invention relates generally to the filed of circuit breakers. More particularly, the present invention relates to a pin free circuit breaker assembly having revolute joints.
BACKGROUND AND THE PRIOR ART
Circuit Breaker is a mechanical switching device capable of making, carrying and breaking currents. Under normal circuit conditions it will make the circuit closed, carry current for a specified time and breaks the circuit under specified abnormal circuit conditions.
Molded Case Circuit Breakers (MCCB) is employed for current interruption. More particularly MCCBs are utilized to protect instruments from damage during adverse conditions prevailing during the operation of the circuit in which molded case circuit breaker is employed. During adverse conditions like short circuit, the current rises to an alarmingly high level. This high current may cause damage to the parts in the electrical system. Hence during these conditions the circuit has to be opened to protect the parts after the breaker.
A circuit breaker can be manually opened and closed, as well as automatically opened to protect conductors or equipments from damage caused by excessive heating due to over current in abnormal conditions such as overload or short-circuit. 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.
Five operations that are to be performed by the MCCB mechanism are: ON, OFF, TRIP, TRIP FREE, RESET. The 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. In conventional type MCCBs, breaker will feature three positions in the top cover near the knob to show ON, OFF and TRIP. When the knob indicates ON it means the breaker is in ON condition i.e., the current path is closed. 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 will be near the center (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. 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 (Driver link) 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, the knob of the breaker has to be taken from their respective ON or OFF positions to a position called dead center beyond which he mechanism becomes independent of the operator and completes the respective action by its own automatically.

The main drawback associated with the conventional system is that the Pins are created by turning usually, and this is an expensive operation. For high volume processes mechanisms without pins are recommended. Pins however are a quintessential part of mechanisms, as they provide an easy way of creating pivot axes. Pins are very difficult to assembly, as they typically use riveting or threading for created fastened permanent joints with lateral members.
The current invention therefore provides a way to create an assembly of linkages which avoids the use of pins. This is done by creating a combination of flared protrusions and groves in the mating member creating an instantaneous pivot axis for revolute coupling. The components show an ease of assembly by avoiding additional fastening processes and providing a base for piling up the subsequent components in the assembly.
OBJECTS OF THE INVENTION
A basic object of the present invention is to overcome the disadvantages/drawbacks of the known art.
Another object of the present invention is to provide a pin free circuit breaker assembly having revolute joints.
Yet another object of the present invention is to facilitate an easy and cost effective assembly of circuit breakers.
These and other advantages of the present invention will become readily apparent from the following detailed description read in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION
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.
In an aspect of the present invention, there is provided an assembly of linkage for circuit breaker(s), said assembly comprising:
at least one bearing plate having plurality of pivot holes for mounting a latch link with plurality of flarings, a latch bracket with plurality of flarings and a de-latcher; said latch link and said latch bracket mounted on said bearing plate by matching the axis of said flaring with said pivot hole in said bearing plate;
a de-latcher assembly comprises said de-latcher with plurality of holes and a biasing spring, said biasing spring is mounted with said delatcher using a de-latcher pivot pin in said holes provided on said de-latcher; said de-latcher assembly connected to said bearing plate using said de-latcher pivot pin;
a upper link having plurality of groves connected to said latch link;
at least one lower link having plurality of pivot holes attached with a spring pin; said lower link pivotable assembled with said upper link by connecting groves in said upper link with holes in said lower link;
a driver link having plurality of holes operatively connected to said bearing plates by placing grove in said driver link on indentation in said bearing plates;
plurality of main spring having one or more hooks on both ends assembled with said lower by connecting one end of the hooks with said spring pin and other end

of the hooks of said main spring assembled with said driver link therefore said driver link operatively pivoted over the indentation in said bearing plates.
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 ACCOMPANYING DRAWINGS
The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.
Reference is first invited to Fig 1 where the Full assembly is illustrated.
Figure.2 illustrates the mechanism assembly with structural members
Figure.3 illustrates the mechanism assembly
Figure.4 illustrates the exploded view of the mechanism
Figure.5 illustrates the mechanism assembly in the ON condition
Figure.6 illustrates the Mechanism assembly in the OFF condition
Figure.7 illustrates the Cross section of the mechanism
Figure.8 illustrates the Bearing Plate
Figure.9 illustrates the Latch link
Figure.10 illustrates the Latch bracket
Figure.11 illustrates the De-Latcher

Figure.12 illustrates the Lower Link Figure.13 illustrates the Upper Link Figure.14 illustrates the Spring Pin Figure.15 illustrates the Bearing Plate Figure.16 illustrates the De-Latcher pivot pin Figure.17 illustrates the Restricting pin Figure.18 illustrates the Driver Link Figure.19 illustrates the Main spring Figure.20 illustrates the Biasing spring Figure.21 illustrates the Driving Pin
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 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.
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 provides an assembly of linkage for circuit breaker(s). The assembly comprises at least one bearing plate 47 housing a restricting pin 49 and a pivot pin for the delatcher 48 as shown in Fig.4. The latch link 41 is assembled into the bearing plate 47 by matching the axes of the Flaring in the latchlink 411 and the pivot hole in the bearing plate 472 as shown in Fig.4. The delatcher is assembled along with biasing spring 4112 into the said assembly by matching the pivot hole in the delatcher 431 and the delatcher pivot pin 48. The above said assembly structure biasing spring 4112, In which the fixed arm a is rested against bearing plate 474 and moving arm b on to the del-latcher surface 434. The latch bracket too is assembled in a similar manner by matching the axis

of the flaring in the latch bracket with the pivot hole in the bearing plate 473. The upper link 45 is assembled with the latchlink 41 by matching the axes of the grove in the upperlink 451 and the flaring in the latchlink for upperlink 412. Lower links 44 are attached to the spring pin 46 by matching the axis of the spring pin and the pivot hole in the lower link for upper link 441 as shown in Fig. 4. This assembly is assembled pivotable with the upperlink 45 by matching the axis of the lower link 44 with that of the grove in the upperlink for the lower link 452. A plurality of main springs 4111 is assembled by placing one of the hooks around the spring pin 46 as shown in Fig. 7. Another bearing plate can be mounted on the assembly as shown in Fig.4. The shoulders in the bearing plate jut out in the lateral direction to their plane as shown in Fig. 8. A Driver link 410 is placed on top of this mechanism by placing the grove in the driver link on the indentation in the shoulders 4711 of the bearing plates 4101 with that of the as shown in Fig.3. The driver link 410 houses holes to accommodate the hooks of the main springs 4111 as shown in Fig 2. The driver link thus operably pivots over the exposed indentations in the bearing plates. The embodiment is retained by the elasticity present in the springs thus allowing for the motion of the many linkages.
The mechanism is mounted onto a structural member 6 which houses a rotating member 5 and is fastened. The axes of the rotating member and the instantaneous axis of rotation created by the driving link 410 are parallel. The bearing plates 47 thus do not experience any relative motion with respect to the structural member 6. The lower link 44 is assembled pivotably with the rotating member 5 as shown in fig. 1. The motion of the lower link 44 thus actuates the motion of the rotating member 5.
The rotating member 5 can traverse multiple discrete positions with respect to the structural member 6. The motion of the driving link 410 actuates the motion of the upper link 45, the motion of which in turn actuates the motion of the lower link 44.

The invention provides a way to avoid the use of pins in the mechanism assembly. It also makes the assembly simpler. There is provided a pin-free assembly of circuit breakers. The current invention defines a way to create an assembly of linkages that avoids the use of pins by creating a combination of flared protrusions and groves in the mating member thereby creating an instantaneous pivot axis for revolute coupling. The improvement is primarily delivered by the use of flaring in planar members and combining these with groves made in mounting members to provide pivot axes for revolute joints.
The improvement is primarily delivered by the use of flaring in planar members, and combining these with groves made in mounting members to provide pivot axes for revolute joints. Construction details along with their reference numerals are as follows:
1 Full assembly
2 Mechanism assembly with a plurality of structural members 3. Mechanism assembly with a single structural member
4 Mechanism 41 Latch link
411 Flaring in the latchlink
412 Flaring in the latchlinik for upper link
413 flapped appendages
414 stopper for upperlink
415 Cam for latch bracket retainer
416 Latching surface 42 Latch bracket

417 Flaring in the latch bracket
418 Latching surface on latch bracket
419 Retaining cam profile
43 De-Latcher
431 Pivot hole in the delatcher
432 Shoulder for lateral tripping
433 Stopper face
434 de-latcher surface
44 Lower link
441 Pivot hole for upper link
442 Pivot hole for rotating member
45 upper link
451 Grove in the upper link
452 Grove in the upper link for lower link

46 Spring pin
47 Bearing plate
471 Shoulder in bearing plate
4711 Indentation in the shoulder of the bearing plate
472 Pivot hole in the bearing plate for latch link
473 Pivot hole in the bearing plate for the latch bracket
474 Stopper for delatcher

475 Mechanism mounting holes
48 De-Latcher pivot pin
49 Restricting pin
410 Driver link
4101 Grove in the driver link
4102 Cam profile on driver link
411 Retainig spring
4111 Main spring.
4112 Biasing spring
a. fixed arm
b. moving arm
412 Driving pin
5. Rotating member
6. Structural member
The features of the invention are the groves created in the mounting members and the flaring provided in the lateral members to create a revolute joint. The indentation created in the shoulder of the bearing plate 4711 which traps the driving member thus allowing only a single axis of rotation too is a novel feature. The De- latcher pivot pin 48 is a multifunctional stepped shaft. The disclosed invention has a flapped appendages 413 on the rear end latch link 41 due to which it has reduced reset operating force. The Latching area of latch link 41 with latch bracket 42 is greater.

The benefits include the exclusion of pins to create revolute joints and an ease of assembly.
Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein with modifications. However, all such modifications are deemed to be within the scope of the invention.
It is also to be understood that the description is intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.

WE CLAIM:
1. An assembly of linkage for circuit breakers, said assembly comprising:
at least one bearing plate having plurality of pivot holes for mounting a latch link with plurality of flarings, a latch bracket with plurality of flarings and a de-latcher; said latch link and said latch bracket mounted on said bearing plate by matching the axis of said flaring with said pivot hole in said bearing plate;
a de-latcher assembly comprises said de-latcher with plurality of holes and a biasing spring, said biasing spring is mounted with said delatcher using a de-latcher pivot pin in said holes provided on said de-latcher; said de-latcher assembly connected to said bearing plate using said de-latcher pivot pin;
a upper link having plurality of groves connected to said latch link;
at least one lower link having plurality of pivot holes attached with a spring pin; said lower link pivotable assembled with said upper link by connecting groves in said upper link with holes in said lower link;
a driver link having plurality of holes operatively connected to said bearing plates by placing grove in said driver link on indentation in said bearing plates;
plurality of main spring having one or more hooks on both ends assembled with said lower by connecting one end of the hooks with said spring pin and other end of the hooks of said main spring assembled with said driver link therefore said driver link operatively pivoted over the indentation in said bearing plates.
2. The assembly as claimed in claim 1, wherein said assembly is mounted on
a structural member of said circuit breaker.

3. The assembly as claimed in claim 1, wherein said structural member comprises a rotating member.
4. The assembly as claimed in claim 1, wherein said lower link is assembled pivotably with said rotating member providing motion to said lower link for actuating said rotating member.
5. The assembly as claimed in claim 1, wherein said rotating member is traversing multiple discrete position(s) with respect to said structural member.
6. The assembly as claimed in claim 1, wherein motion of said driving link actuating the motion of said upper link, therefore said upper link actuates the motion of said lower link.
7. The assembly as claimed in claim 1, wherein indentation in the shoulder of said bearing plate is provided for holding said driving link, therefore allowing a single axis of rotation.
8. The assembly as claimed in claim 1, wherein said de-latcher pivot pin is acting as a multifunctional stepped shaft.
9. The assembly as claimed in claim 1, wherein said latch link comprising a flapped appendage(s) on the rear end for reducing reset operating force.
10. The assembly as claimed in claim 1, wherein said main spring and said biasing spring providing the motion of the linkage(s)in said assembly.
11. The assembly as claimed in claim 1, wherein said biasing spring having a fixed arm and moving arm.

12. The assembly as claimed in claim 11, wherein said fixed arm is rested on said bearing plate and said moving arm rested in said de-latcher surface.