DESC:TECHNICAL FIELD OF THE INVENTION

This invention relates generally to the molded case circuit breaker (MCCB) for operating contact system using mechanism more particularly, provides a mechanical assembly of linkages for operating the contact system in circuit breaker. The mechanical assembly is simple and providing high mechanical life to the circuit breaker.

BACKGROUND AND THE PRIOR ART

The circuit breakers are 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. A molded case circuit breakers (MCCB) is employed for current interruption. 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.

The 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. The MCCB mechanism performed the following operations: ON, OFF, TRIP, TRIP FREE, RESET in the MCCB. The first two operations i.e., ON and OFF 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 later 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. The 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, operator 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 the mechanism becomes independent of the operator and completes the respective action by its own automatically.

WO2010079110 discloses a control mechanism for the displacement of at least one moving contact of a low-voltage circuit-breaking device. The control mechanism comprises elastic means operatively connectable to the moving contact, at least a first element of which is operatively connected to a second element by means of pin-shaped connection means. The first and second elements each comprise a pair of facing lateral portions that are connected by a transverse portion. The pin-shaped connection means comprise a pair of pin-shaped ends each of which emerges from one side of a lateral portion of the first element. Said pin-shaped means also comprise a pair of seats each of which is defined on a lateral portion of the second element. Each pin-shaped end is inserted in a corresponding seat so as to configure an axis of mutual rotation between the first and the second elements. The elastic means are arranged so as to exert a retaining force on the pin-shaped ends sufficient to keep them coupled to the corresponding seats in which they are inserted.

In the present invention a joint between female seats and male pin-shaped ends to create contactable rotatable pivot axes.

US4528531 discloses a molded case circuit breaker includes a highly integrated operating mechanism having an over-center toggle mechanism for opening and closing a pair of electrical contacts and a trip mechanism for responding to overload and short circuit or fault current conditions to separate the pair of electrical contacts. A generally flat, intermediate latch 1 plate includes an upper latch 1 surface for latch 1ing with a movable cradle of the over-center toggle mechanism and a lower latch 1 surface for latch 1ing with a trip bar of the trip mechanism and a pair of outwardly projecting pivot arms disposed between the upper and lower latch 1 surfaces. The over-center toggle mechanism includes a pair of upper toggle links and a pair of lower toggle links interconnected by a toggle spring pin. To increase the speed of separation of the first and second electrical contacts during a trip operation, the cradle is physically configure to engage and upwardly propel the toggle spring pin and, also, the upper toggle links have projections for physically contacting a rigid stop.

US4864263 discloses an industrial rated molded case circuit breaker having an electronic trip circuit contained within the circuit breaker enclosure includes a reset spring in cooperation with the circuit breaker latch 1 spring to insure manual reset of circuit breaker after an automatic trip function. The reset spring allows the circuit breaker latch 1 assembly to be manually reset upon minimum travel of the circuit breaker operating handle due to internal circuit breaker component space restrictions. The circuit breaker latch 1 assembly is robotically loaded to the operating mechanism which is then attached to the circuit breaker case by an automated fastening process.

US6479774 discloses a circuit breaker operating mechanism comprises a movable handle yoke, a mechanism spring extending in tension from the handle yoke to a pin, and a lower link extending from the pin to a crank connected to a contact arm bearing a movable contact. The crank can be positioned in open and closed conditions, being in an open position when the movable contact is separated from an associated fixed contact and being in a closed position when the movable contact is mated to associated fixed contact. The circuit breaker further comprises an interface formed on said crank and a blocking prop having a first surface that engages said interface, the first surface preventing the crank from rotating towards the closed position.

US6590172 discloses a circuit breaker is provided wherein the circuit breaker comprises a contact arm movable between a closed position, an open position and a blown open position wherein the contact arm is disposed in the circuit breaker. A bumper disposed to contact the contact arm when the contact arm is in the blown open position. In addition, a stop member disposed to be in contact with a linkage assembly so as to create a gap between the bumper and the contact arm when the contact arm is disposed in the open position.

US5369384 discloses a breaker mechanism for power circuit breakers is the energy storage link between the handle and the contact systems. Known breaker mechanisms are generally too expensive to manufacture. When contact welding occurs, there is also the risk that, in spite of the tripping of the breaker mechanism, the contact system will not open. The new breaker mechanism reliably opens the contact system and consists of fewer and technologically simpler individual parts. It is inserted between two symmetrical breaker plates held in die cast housing, and in which a connecting piece is mounted. Two toggle levers are connected at a distance from one another by means of a connecting shaft engaged in crossbar cam slots. A toggle lever spring is engaged between the connecting piece and the connecting shaft. A bracing lever which can be driven by the connecting piece is friction locked in the breaker plates, and the toggle levers in the bracing lever. A latch 1 lever and a latch 1 holding the latter in the locked position are friction locked by means of a latch 1 spring in recesses of the breaker plates.

DE102006038191 which came up on the International Search Report discloses an invention regarding the fixing of a switching mechanism device onto a carrier whereas present invention is regarding the operating mechanism for a switching device itself.

US20020100674 which came up on the International Search Report discloses an invention regarding a motor operator which is a driving means for the operating mechanism of a switching device whereas present invention is regarding the operating mechanism for a switching device itself.

EP 0798755 which came up on the International Search Report discloses an invention regarding only the latch 1ing system and release mechanism for electrical switching devices whereas present invention is regarding the operating mechanism of a switching device.

DE 102006059307 discloses an invention where the object is of converting a double breaker switching device to a single breaker switching device, with higher commonalities. The specified single breaker switching device requires a higher rotation with respect to the double breaker switching device within the same boundary conditions. The invention increases the trip rotation by increasing the distance between the supporting lever axis and the upper lever, lower lever pivot by pivoting the lower lever on a different additional axis.

DISADVANTAGES OF THE PRIOR ART

· Pins are created by turning usually, and this is an expensive operation. For high volume processes and Especially in Automation of Mechanism assembly 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 and these processes are Tiresome. As riveting is semi permanent joint so sometimes it may fail during operation. Use of pins for Mechanism always adds time and cost to final product and also that is responsible for low production rate.
· Improvement required in latch system to overcome problem of De-latching after few mechanical operations
· Use of large no. of components to assemble mechanism
· Hardware required to assemble and to fix the mechanism.
· Less mechanical life
· High Friction

The present invention overcomes the disadvantages of the prior arts and provides an assembly of linkages which avoid the use of pins. This is done by creating a combination of flared height from component itself and groves in the mating member creating an instantaneous pivot axis for revolute coupling by using current improved manufacturing process.
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 mechanical assembly for operating the contact system in the circuit breaker.

Another object of the present invention is to provide an assembly of linkages which avoids the use of pins to make the assembly simpler and to provide high mechanical life.

Another object of the present invention is to provide indentation created in the shoulder of the bearing plate of the circuit breaker which traps the driving member thus allowing only a single axis of rotation.

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

In an aspect of the present invention, there is provided an assembly for operating the contact system in the circuit breaker, said assembly comprising:
at least two bearing plates (6, 7) having at least a stopper, a plurality of protrusions, a plurality of slot(s), and at least one pivot hole;
a latch link (8) having a plurality of protrusions (81, 89, 87, 82, 83, 85), a stopper (88), at least one projection (86), and at least one latching surface (84);
a latch bracket (11) having at least two latching surface (111, 116), at least one cam profile (112), at least two holes (113, 117), at least one stopper (114), and at least one slot (115);
an upper link (9) having a plurality of groves (91, 92, 93) and at least one stopper (94);
a lower link (10) having a plurality of protrusions and a plurality of holes;
a fork (16) having a plurality of holes, a plurality of groves (164, 165), at least one stopper (162) and a cam profile (161);
a de-latcher (13) operatively connected to said bearing plates through said slots (67, 77); and
a biasing spring (14) connected between said latch bracket (11) and said de-latcher (13);
CHARACTERIZED IN THAT
said latch link is connected to said bearing plate(s) by attaching said protrusion (81, 89) with said pivot hole (70)co-axially;
said latch bracket connected to said bearing plate (s) by attaching said holes (113, 117) with said protrusion (63, 73) co-axially;
said upper link connected to said latch link (8) coaxially through said groove (91) with said protrusion (82 ) on said latch link (8);
said lower link pivotally connected to said upper link and a mechanism spring (12) through a spring pin by connecting said hole on said lower link with said groves on said upper link(92, 93); and
said fork operatively connected to said bearing plate (s) by attaching said groves (164, 165) with an indentation (65, 75) on said bearing plate (s).

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.
Figure1 illustrates the perspective view of breaker.
Figure 2 illustrates the perspective view of mechanism with housing.
Figure 3 illustrates the stand alone mechanism assembly with all components.
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.
Figure7 illustrates the cross section of the mechanism with all moving parts.
Figure8 illustrates the mechanism fixing in hosing.
Figure9 illustrates the mechanism fixing cover.
Figure10 illustrates the joining of two moving member.
Figure 11 illustrates the bearing plate right (holding plate).
Figure 12 illustrates the latch plate.
Figure 13 illustrates the bearing plate (holding plate).
Figure 14 illustrates the bearing plate left (holding plate).
Figure 15 illustrates the de-latcher (trip plate).
Figure 16 illustrates the biasing spring.
Figure 17 illustrates the upper link.
Figure 18 illustrates the lower link assembly with spring pin.
Figure 19 illustrates the mechanism operating spring.
Figure 20 illustrates the fork.
Figure 21illustrates the special arrangement of latch bracket and de-latcher with biasing spring.

Persons skilled in the art will appreciate that elements in the figure 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 PRESENT 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 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 assembly for operating the contact system in the circuit breaker. The present invention provides a mechanical assembly of linkages for operating the contact system in circuit breaker. The mechanical assembly is simple and providing high mechanical life to the circuit breaker.

Various parts of the present disclosed assembly:
1. Housing
111 Slot for mechanism Fixing
121 Slot for mechanism Fixing
2. Cover
21, 22 Ensure Mechanism Horizontal Movement
23, 24 Mechanism fixing from cover
3. Top cover
4. Knob
5. PTT
6. Mechanism Fitment In housing (Figure 8)
7. Mechanism fixing from Cover (Figure 9)
8. Full Assembly Breaker
9. Mechanism
6. Bearing Plate Right
61 Fork stopper
62, 69 flat surface for mechanism fixing with cover
63 Protrusion for latch stopper
64, 66 Bend given for mechanism fixing in Housing
67 Hole and slot for De-latcher ease of assembly
68 Protrusion for latch bracket
611 Ring helps to ensure clearance and reduce friction between 7 and 11
7. Bearing Plate Right
71 Fork stopper
72, 79 flat surface for mechanism fixing with cover
73 Protrusion for latch stopper
74, 76 Bend given for mechanism fixing in Housing
77 Hole and slot for De-latcher ease of assembly
78 Protrusion for latch bracket
711 Ring helps to ensure clearance and reduce friction between 7 and 11
8. Latch Link
81 Flaring in the latch link
82, 87 flaring in the latch link for upper link
86 flapped appendages
88 stopper for upper link
90 Cam for latch bracket retainer
84 Latching surface
89 Ring to ensure clearance and to reduce friction with bearing plate 6and7
9. Upper link
91 Grove in the upper link
92, 93 Grove in the upper link for lower link
94 Upper links on stopper
10. Lower Link
101 Lower links protrusion for drive shaft contact
103To ensure that lower link cannot come out of shaft during operation
11 Latch bracket
111 Latching surface on latch bracket
112 Retaining cam profile
114Stopper during Resetting
115Slot for basing spring
116 Latching surface on latch bracket
12 Main Mechanism Spring
13 Trip Bar/ De-latcher
131Stopper during On
132 latch Surface with Latch Bracket
133Cam surface for UV/Shunt tripping
134Trib bar construction
135 Ensures Tripp late Position and restricts side plate opening .
136 Slots for Ease of Assembly
137Biasing spring mounting
14 biasing spring
15 Spring Pin
16 Forks
161 Retaining cam profile
162Stopper during Resetting
164,165Slot for basing spring
M1 Moving Contact
F1 Fixed contact
R1 Rotating Shaft

In one implementation, an assembly is provided for operating the contact system in the circuit breaker, said assembly comprising:
at least two bearing plates (6, 7) having at least a stopper, a plurality of protrusions, a plurality of slot(s), and at least one pivot hole;
a latch link (8) having a plurality of protrusions (81, 89, 87, 82, 83, 85), a stopper (88), at least one projection (86), and at least one latching surface (84);
a latch bracket (11) having at least two latching surface (111, 116), at least one cam profile (112), at least two holes (113, 117), at least one stopper (114), and at least one slot (115);
an upper link (9) having a plurality of groves (91, 92, 93) and at least one stopper (94);
a lower link (10) having a plurality of protrusions and a plurality of holes;
a fork (16) having a plurality of holes, a plurality of groves (164, 165), at least one stopper (162) and a cam profile (161);
a de-latcher (13) operatively connected to said bearing plates through said slots (67, 77); and
a biasing spring (14) connected between said latch bracket (11) and said de-latcher (13);
CHARACTERIZED IN THAT
said latch link is connected to said bearing plate(s) by attaching said protrusion (81, 89) with said pivot hole (70)co-axially;
said latch bracket connected to said bearing plate (s) by attaching said holes (113, 117) with said protrusion (63, 73) co-axially;
said upper link connected to said latch link (8) coaxially through said groove (91) with said protrusion (82 ) on said latch link (8);
said lower link pivotally connected to said upper link and a mechanism spring (12) through a spring pin by connecting said hole on said lower link with said groves on said upper link(92, 93); and
said fork operatively connected to said bearing plate (s) by attaching said groves (164, 165) with an indentation (65, 75) on said bearing plate (s).

In one implementation, said assembly is assembled in a housing of said circuit breaker and operatively connected to a knob of said circuit breaker for operating said contact system in ON, OFF, TRIP and RESET condition with an ease and improving the latch condition between said latch link and said latch bracket, consequently improving the trip life and mechanical life of said circuit breaker.

In one implementation, said biasing spring (14) provides an anticlockwise torque to said latch bracket (11)for maintaining the latch condition between said latch bracket and said latch link to improve de-latched condition in said circuit breaker.

In one implementation, said mechanism spring connected between said spring pin and said fork, provides a force to said fork to keep said bearing plates in close position during normal operation of said circuit breaker.

In one implementation, the assembly comprises a rotating member (R1) connected to said lower link.

In one implementation, the assembly comprises sidewise bending for resetting said circuit breaker.

In one implementation, said biasing spring facilitates auto resetting of said latch bracket during reset condition.

In one implementation, said indentation on said bearing plate (s) (6, 7) allows a single axis of rotation to said fork.

In one implementation, said fork comprises of a plurality of holes for accommodating the hooks of said mechanism spring.

CONSTRUCTION:

The disclosed invention comprises of at least two bearing plates 6,7respectively bearing plate right and bearing plate left. Take bearing plate 6 first as shown in figure 11, the latch link 8, shown in figure 12, is assembled into the bearing plate 6 by matching the axes of the protrusion in the latch link81 and the pivot hole in the bearing plate 70 as shown in figure.4. The latch bracket11 is assembled into the bearing plate 6 by matching the axes of hole in the latch bracket113 and the protrusion in the bearing plate 63 as shown in figure.4. The bearing plate 7, as shown in figure 15, is assembled by matching axes 89 of latch link 8 and axes 113of latch bracket 11.

The de-latcher13 shown in figure 14 is assembled along with biasing spring 14 as shown in figure 16 into slot 137 the said assembly by matching the slots 67 and 77 provided on the bearing plate 6 and 7 respectively and rotate in slot so that it cannot come out during normal open and close condition and other end of the biasing spring 141 stretch and assemble in a slot 115 on latch bracket. Because of spring, the latch bracket has anticlockwise torque that helps mechanism not to de-latch during operating condition. The delatcher 13 has two positions one is its assembly condition in that it can only assemble in and second is during open close condition of mechanism so it cannot come out during mechanism ON, OFF, TRIP condition. The same biasing spring 14 helps trip plate and latch bracket both to reset during resetting of mechanism.
The upper link 09, as shown in figure17, is assembled with the latch link8 by matching the axes of the grove in the upper link91 and the flaring in the latch link for upper link82. The lower links 10 are attached to the spring pin 15 and main mechanism spring 12 by matching the axis of the spring pin and the pivot hole in the lower link for upper link93 as shown in figure. 4. This assembly is assembled with the upper link93by matching the axis of the lower link 153 with that of the grove 152 in the spring pin. now fork 16 as shown in figure 20, is placed on top of this mechanism by placing the grove164, 165 in the fork on the indentation in the shoulders 65, 75 of the bearing plates 6,7with that of the as shown in figure4.The fork16houses some holes to accommodate the hooks of the main springs 12as shown in figure 3, hence fork link thus operable 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. Since there is no rivets or pins used to assemble rotating members this assembly takes less time in compare with other available mechanisms. Ease of assembly reduces the cost of mechanism and production can be increase by large amount by using automation facilities to assemble the mechanism. This invention includes large surface area and length of that area of latch surface of latch link 9 and latch bracket 8 gives positive latching and improvement in trip life and mechanism life as well. Large length of latching ensures good latching if we consider all clearance and tolerance of components instead of single point latching.

The mechanism operating spring 12 which is connected between springs pin 15 and fork 16.this applies force on fork 16. fork 16 sits on bearing plate right and bearing plate left respectively this force helps bearing plate not to open up outside during normal operation also rings provided on de-latcher 13 that has force of biasing spring that restricts bearing plates to open sidewise as well. This type of arrangement helps mechanism not to de-assemble as well.

The mechanism is assembled with rotating member R1 with lower link 10 and full assembly assemble in slots 11,12,13,14 on housing 1 so no extra hardware required to fix on hosing. The motion of the lower link 10thus actuates the motion of the rotating member r1.the bearing plates 6and7, thus do not experience any relative motion with respect to the structural member 1.assemble knob 4 on fork 16 as shown in figure. cover is mounted on breaker such that surface 23,24,25,26sits on mechanism bearing plate surface 62,69,72,79 so that movement of mechanism can be restricted and proper position of mechanism can be ensure. Thus no single hardware required to fix the mechanism cover and housing fixing screw will help indirectly.

Mechanism is designed such that by less rotation of fork 16 all required outputs achieved successfully and due to that no extra component required to achieve the requirement. That function achieved by rotation of fork 16 and knob 4 design as well. This invention includes special type of circular protrusions that have small ring 89, 611, 711 and then pin shaped circular that ring ensures clearance between two members and also it has less effective touching area between two component that reduces overall friction of members

FEATURES AND BENEFITS

· The features of the invention are the groves created in the mounting members and the protrusion provided in the lateral members to create a revolute joint.
· The indentation created in the shoulder of the bearing plate 6and7 which traps the driving member thus allowing only a single axis of rotation too is a novel feature.
· The de-latcher is designed such way that it has features that helps accessories for tripping the shaft without extra component. This ensures the better tripping in compare with other tripping system with extra component.
· The disclosed invention has a flapped appendage86 on the rear end latch link 8 due to which it has reduced reset operating force.
· The latching area of latch link 8 with latch bracket 11 is greater so it has less de-latching issues.
· Special arrangement of biasing spring (extension) helps to overcome de-latching
· (Nuisance tripping) issues after few mechanical operations.
· The benefits include the exclusion of pins to create revolute joints and an ease of assembly and reduces the cost and components in the whole mechanism.
· Enabling higher rotation of moving contact.
· better ergonomic considerations
· Less number of components.
· Less no. components results less friction
· No nuisance tripping in shock and vibration tests.

In one impledmentnantion, a mechanism assembly (9) is mounted on the hosing (1) without any hardware. A special arrangement has been provided on the housing (1) and slots (111,121) are provided for bearing plate fixing in front and back side of the housing(1) as shown in figure5,6,7,8. Further, the mechanism assembly (9) is vertically held by top cover (2). Slots may be provided on the top cover 23,24 ensures the vertical fixing of mechanism as shown in figure6,7,9.Top cover (2) sits on the housing assembly(1) after assembly of mechanism and all other components. The mechanisms side by side fixing (Opening of side plate by side) may be restricted by 21, 22 wall on the top cover (2). Thus mechanism movement and fixing is done by four point contact that gives stability to mechanism. This type of stability of mechanism has more mechanical life.

NOVEL FEATURES:

1. Special arrangement of extension spring used as a biasing spring 14 to have a better latching between latch bracket 11 and trip plate 13. This spring gives anticlockwise torque on latch bracket so that it always tries to keep latch bracket 11. In latch condition with the latch link 8.because of this feature de-latching (nuisance tripping) of mechanism is reduced hugely this improves breaker’s life as well. This spring also helps latch bracket auto resetting when we reset mechanism.

2.Protrusion given on component latch link 8,bearing plate 6 and 7 has a better strength in compare with semi permanent joints with rivets, this adds better strength to components and assembly also protrusion in components reduces total headcount of components that help to reduce cost and helps in ease of assembly as well.

3. No hardware used to assemble mechanism and also to fix the mechanism. This reduces time and ease of assembly is achieved .housing 1 and cover 2 has features so that mechanism movement and they ensure proper position of the mechanism and functions. This saves cost and assembly time of mechanism and breaker. Mechanism sits on four surface of housing 1 and also slots on housing restrict mechanism’s forward and backward movement. Cover 2 holds mechanism on for point that restricts mechanisms up and down movement in assembly that same wall restricts bearing plate 6, 7 to open sidewise. Thus mechanism movement and fixing is done by four point contact that gives stability to mechanism. This type of stability of mechanism has more mechanical life.

4. Special type of circular protrusion with ring 89,611,711which gives small effective surface between two moving member made in components helps to reduce overall friction of mechanism.

5. Mechanism operating spring 12 which is connected between spring pin 15 and fork 16.This applies force on fork 16. fork 16 sits on bearing plate right and bearing plate left respectively this force helps bearing plate not to open up outside during normal operation also rings provided on de-latcher 13 that has force of biasing spring that restricts bearing plates to open sidewise as well. This type of arrangement helps mechanism not to de-assemble as well.

6. Positive latching between latch bracket and trip plate helps to avoid nuisance tripping.

7. A latch link having sidewise bending for resetting of breaker instead of roller pin and that is making a cam like surfaces which mate with the cam surface of fork 16.this arrangement helps to reduce resetting force for mechanism.

8. Large surface area and length of that area of latch surface of latch link 9 and latch bracket 8 gives positive latching and improvement in trip life and mechanism life as well. Large length of latching ensures good latching if we consider all clearance and tolerance of components instead of single point latching.

9. Compatible mechanism for modular and non-modular construction this gives benefits to breaker construction.

10. upper link 9 sits on latch link 8 .during on –off operation upper link tries to come out of the circular protrusion 82,87but extension spring 12 restricts upper-link to come out of that same as spring requires one axes to operate so ensure the spring position upper link inner distance helps to be in proper place.

ADVANTAGES:

· The components explained in the present invention are show an ease of assembly by avoiding additional fastening processes and providing a base for piling up the subsequent components in the assembly.
· Flared height which is pin shaped and made from component itself can be consider as a permanent joint so it has more strength compare to riveted pins and risk of failure is less compare to riveted means.
· Ease of assembly can help in automation for assembling the mechanism parts and reduces time and cost of final product and also better productivity can be achieved.
· Improved latch system designed such that problem of de-latching can be solved and by the same time less trip force is archived for accessories tripping.
· Current invention is designed so that it doesn’t require any hardware to assemble and to fix the mechanism detail is discussed below.
· Components and its ergonomic structures are designed such a way that this type of mechanism has high mechanical life
· Mechanism is having less no. of components that reduces overall friction in mechanism.
,CLAIMS:1. An assembly for operating the contact system in the circuit breaker, said assembly comprising:
at least two bearing plates (6, 7) having at least a stopper, a plurality of protrusions, a plurality of slot(s), and at least one pivot hole;
a latch link (8) having a plurality of protrusions (81, 89, 87, 82, 83, 85), a stopper (88), at least one projection (86), and at least one latching surface (84);
a latch bracket (11) having at least two latching surface (111, 116), at least one cam profile (112), at least two holes (113, 117), at least one stopper (114), and at least one slot (115);
an upper link (9) having a plurality of groves (91, 92, 93) and at least one stopper (94);
a lower link (10) having a plurality of protrusions and a plurality of holes;
a fork (16) having a plurality of holes, a plurality of groves (164,165), at least one stopper(162) and a cam profile (161);
a de-latcher (13) operatively connected to said bearing plates through said slots (67, 77); and
a biasing spring (14) connected between said latch bracket (11) and said de-latcher (13);
CHARACTERIZED IN THAT
said latch link is connected to said bearing plate(s) by attaching said protrusion (81, 89) with said pivot hole (70)co-axially;
said latch bracket connected to said bearing plate (s) by attaching said holes (113, 117) with said protrusion (63, 73) co-axially;
said upper link connected to said latch link (8) coaxially through said groove (91) with said protrusion (82 ) on said latch link (8);
said lower link pivotally connected to said upper link and a mechanism spring (12) through a spring pin by connecting said hole on said lower link with said groves on said upper link(92, 93); and
said fork operatively connected to said bearing plate (s) by attaching said groves (164, 165) with an indentation (65, 75) on said bearing plate (s).

2. The assembly as claimed in any of the preceding claims, wherein said assembly is assembled in a housing of said circuit breaker and operatively connected to a knob of said circuit breaker for operating said contact system in ON, OFF, TRIP and RESET condition with an ease and improving the latch condition between said latch link and said latch bracket, consequently improving the trip life and mechanical life of said circuit breaker.

3. The assembly as claimed in any of the preceding claims, wherein said biasing spring(14) provides an anticlockwise torque to said latch bracket (11) for maintaining the latch condition between said latch bracket and said latch link to improve de-latched condition in said circuit breaker.

4. The assembly as claimed in any of the preceding claims, wherein said mechanism spring connected between said spring pin and said fork, provides a force to said fork to keep said bearing plates in close position during normal operation of said circuit breaker.

5. The assembly as claimed in any of the preceding claims, wherein said de-latcher comprises at least one ring to restrict the opening of said bearing plate(s) sidewise during normal operation of said circuit breaker.

6. The assembly as claimed in any of the preceding claims comprises a rotating member (R1) connected to said lower link.

7. The assembly as claimed in any of the preceding claims, wherein said latch link comprises sidewise bending for resetting said circuit breaker.

8. The assembly as claimed in any of the preceding claims, wherein said biasing spring facilitates auto resetting of said latch bracket during reset condition.
9. The assembly as claimed in any of the preceding claims, wherein said indentation on said bearing plate (s) (6, 7) allows a single axis of rotation to said fork.

10. The assembly as claimed in any of the preceding claims, wherein said fork comprises of a plurality of holes for accommodating the hooks of said mechanism spring.