The present subject matter described herein, in general, relates to the field of circuit breakers, and more particularly to a molded case circuit breaker with a dual cam arrangement to serve the purpose of tripping effectively during assembly of internal accessories.
BACKGROUND
In general the function of a circuit breaker is to electrically engage and disengage a selected circuit from an electrical power supply. This function occurs by engaging and disengaging a pair of operating contacts for each phase of the circuit breaker. The circuit breaker provides protection against persistent overcurrent conditions and against the very high currents produced by short circuits.
A Molded Case Circuit Breaker widely known as MCCB, is one which is amass in closed housing of insulating material for making, carrying and breaking currents under normal and abnormal condition. It should be work acceptably under overload and short circuit conditions as per design. Molded Case Circuit Breakers are mostly designed to deliver protection to low voltage distribution systems.
The MCCB is being increasingly accepted in Indian industries as a circuit protection device with several advantages over old age practice of using switch and fuse units. There has been a nonstop surge in the manufacture of MCCB's because of number of factors, such as compactness and market stresses, consistent performance, use of advanced rating insulating material and introduction of new technologies such as solid state and microprocessor-based trip and control systems. These improvements have significantly enlarged the system flexibility of MCCB and it is now possible to adapt a MCCB to an extensive variety of applications.

The primary function of MCCBs is to keep protected core circuit elements in the event of an unnecessary fault. A MCCB mechanically separates the electrical circuit under continued overloads or short circuit.
An under voltage trip device is an optional accessory in a circuit breaker that mechanically trips the breaker when voltage to the terminals drops below a threshold level. A shunt device trips the circuit breaker on receiving supply from the control room. This alleviate remote tripping feature. Thus, the major disadvantage of existing products is the use of extra components to adapt the same feature. It increases the assembly time and cost as well.
Prior art reference is made to a document US4166260 which discloses a circuit breaker accessory assembly, such as a shunt trip solenoid, is affixed to an insulative mounting member which is interchangeably mounted in place of a conventional interphase barrier within the breaker molded case. The trip solenoid plunger is operatively coupled with the breaker common trip bar, while the actuator for a normally closed switch wired in the solenoid energization circuit is positionally mounted for actuation by movement of a breaker contact arm to its open circuit position, thereby opening the switch.
Further, reference is made to a document US5093643 which discloses a molded-case circuit breaker having an undervoltage release device housed therein is provided with a flexible molded double ended lever for resetting the undervoltage release device and a torsion spring braced upon the two arms of the lever so as to minimize the effects of stress and creep on the molded members when manually actuating repeatedly to reset the undervoltage release device against the biasing spring of the device.

Further, reference is made to a document US6201460 Bl which discloses an undervoltage release device for a circuit breaker is disclosed having an operating mechanism, a trip bar, line and load terminals, and a cover. The device includes a housing, a solenoid, upper and lower actuators aligned with a plunger of the solenoid and in selective contact with the trip bar, plunger and actuator reset levers mounted upon the solenoid frame, and pair of terminals in electrical contact with the solenoid coil and line terminals of the breaker, wherein the force of the solenoid corresponds to the line voltage. Also disclosed is a method for tripping a circuit breaker when line voltage drops below a selected value, in a circuit breaker having an operating mechanism and a trip unit with an intermediate latch. The method includes steps of closing the circuit breaker with the operating mechanism, installing the device in a cover of the circuit breaker, the device having a solenoid with a plunger and a plurality of actuators in selective contact with the plunger and the trip unit; and wiring the solenoid in parallel with the load circuit, wherein the magnetic force of the solenoid is proportional to the line voltage and maintains the plunger in contact with the actuators, and wherein the plunger is released by the solenoid when the line voltage drops below the selected value, thereby providing for at least one actuator to contact the trip unit and open the circuit breaker.
However, the above patents uses initially the CAM arrangement while doing assembly of the internal accessory which is given by an extra component assembled on chassis. This component ensures the hitting of mechanism trip plate during the assembly of any accessory while in normal operation slider mechanism is used to trip the MCCB using the same extra component.
Thus, in view of the drawbacks of the prior art, there exists a dire need for an improvement mechanism related to the features of internal accessories to assemble them with ease and serve the purpose of tripping effectively during assembly.

SUMMARY OF THE INVENTION:
This summary is provided to introduce a selection of concepts in a simplified format that is further described in the detailed description. This summary is not intended to identify key or essential inventive concepts.
An objective of the present invention is to provide a molded case circuit breaker with a dual cam arrangement between a trip plate and an accessory actuator.
Another object of the present additional invention is to avoid an extra component in integration of accessories inside cover cavity which reduces assembly time, product weight and high manufacturing cost of new component.
Accordingly, in one aspect, the present invention provides a molded case circuit breaker (MCCB) comprising: a cover cavity having one or more internal accessory unit; at least a trip plate; and a dual cam arrangement between said trip plate and an accessory actuator. The dual cam arrangement comprising:
a cam profile 1 of said trip plate and said accessory actuator, wherein said cam profile of said accessory actuator interacts with said cam profile of said trip plate when said MCCB is in ON condition and during assembly of said one or more internal accessory inside said cover cavity;
a cam profile 2 of said trip plate and said accessory actuator, wherein during said MCCB tripping operation, said cam profile 2 of said accessory actuator interacts with said cam profile of said trip plate at an interaction point of 15 mm from a center of said trip plate to reduce a high tripping force.

In one implementation, said cam profile 1 of said accessory actuator ensures said trip plate rotation in a clockwise direction to enable tripping of said MCCB.
In one implementation, the accessory actuator is adapted to directly interact with trip plate during accessory assembly and inside said cover cavity to ensure robust tripping arrangement.
In one implementation, the MCCB further comprises a slot arrangement between said cover cavity and an accessory housing guiding profile to ensure accessory position during and after assembly for smooth integration between said trip plate and said accessory actuator.
In one implementation, final rotational in said clockwise direction of said trip plate to trip said MCCB achieved by means of changing of said interaction point between said trip plate and said cam profile 2 of said accessory actuator from 15mm to 9mm.
In second aspect, in one implementation, the present invention provides a dual cam arrangement for a circuit breaker arranged between a trip plate and an accessory actuator, wherein said dual cam arrangement comprising:
a cam profile 1 of said trip plate and said accessory actuator, wherein said cam profile of said accessory actuator interacts with said cam profile of said trip plate when said MCCB is in ON condition and during assembly of one or more internal accessory inside a cover cavity;
a cam profile 2 of said trip plate and said accessory actuator, wherein during said MCCB tripping operation, said cam profile 2 of said accessory actuator interacts with said cam profile of said trip plate at an interaction point of 15 mm from a center of said trip plate to reduce a high tripping force.

By going for the arrangement described in the present invention, all the requisite functions can be achieved in a more simplistic way and by using fewer components in comparison to other inventions. Simple and fewer components ensure robust and reliable way of achieving the requisite functions. Further, during normal ON/OFF of breaker it has been taken care that the actuator doesn't interfere with the mechanism trip plate and there is a considerable gap to avoid nuisance tripping.
The above aspects and the advantages will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
It is appreciated that the drawings provided in the present disclosure only illustrate application examples of the present disclosure and are therefore not to be construed as limiting its scope. The foregoing disclosure provides additional information with additional specificity and details with the accompanying drawings, which are listed below for quick reference.
Figure 1 illustrates the basic view of MCCB with accessory fitment,
according to one embodiment of the present invention.
Figure 2 illustrates the section view of top view of MCCB with accessory
fitment, according to one embodiment of the present invention.
Figure 3 shows section A-A with accessory initial guiding profile with
MCCB cover, according to one embodiment of the present invention.
Figure 4 shows section A-A with accessory actuator interface with
mechanism trip plate when MCCB is in ON condition, according to one
embodiment of the present invention.
Figure 5 illustrates Section A-A with accessory final resting surface on
cover and mechanism tripping through UV tripper, according to one
embodiment of the present invention.

Figure 6 shows a basic view of UV with tripping mechanism, according to
one embodiment of the present invention.
Figure 7 illustrates a view of UV with tripper and mounting screw,
according to one embodiment of the present invention.
Figure 8 illustrates a basic view of trip plate with UV tripping profile,
according to one embodiment of the present invention.
Figure 9 illustrates a Section A-A of MCCCB: Gap between accessory
tripper and mechanism side plate in ON condition, according to one
embodiment of the present invention.
Figure 10 illustrates a Section A-A of MCCCB: initial hitting point of
accessory actuator with mechanism trip plate, according to one
embodiment of the present invention.
Figure 11 illustrates a section AA of MCCB: Final hitting point of
accessory actuator with mechanism Tripp lite, according to one
embodiment of the present invention.
Figure 12 illustrates a force diagram of UV with MCCB, according to one
embodiment of the present invention.
It may be noted that the one or more elements may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding of the embodiments of the present disclosure, so as not to obscure the drawings with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein.
DETAILED DESCRIPTION OF THE INVENTION
It should be understood at the outset that although illustrative implementations of the present disclosure are detailed below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present disclosure should be in no way be construed as being limited to the illustrative implementations, drawings,

and techniques, illustrated below, including the exemplary design and implementation illustrated and described herein, but may be modified within the scope of equivalents.
Unless otherwise defined, all terms and especially technical and/or scientific terms, used herein, may be taken to have the same meaning as commonly understood by one ordinarily skilled in the art.
Reference is made herein to some "embodiments". It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the claims. Some embodiments have been described for the purpose of illuminating one or more potential ways in which the specific features and/or elements of the foregoing claims fulfill the requirements of uniqueness, utility, and non-obviousness.
The present subject matter described herein, in general, relates to an integrating of internal accessories namely under voltage release or shunt release so as to trip the MCCB in ON condition during assembly of the accessory. This can be accomplished by tripping the mechanism of MCCB while assembling the accessory using the tripping arrangement from accessory actuator and plastic housing as a guide.
In one implementation, there is provided a dual cam arrangement between a trip plate and an accessory actuator.
a. Cam profile 1 of both trip plate and actuator cam works when
breaker is in ON condition and someone try to assemble accessory
inside cover.
b. Cam profile 2 of both trip plate and actuator cam works when
accessory is fully assembled into the cover cavity.
• During MCCB tripping operation from accessory cam 2 of both trip plate and actuator interacts at 15mm from the trip

plate center and reduce initial high tripping force of the mechanism. -• Final rotational clockwise direction of trip plate trip the mechanism is achieved by means of changing of interaction point between trip plate and actuator cam 2 from 15mm to 9mm.
In one implementation, the parts and components as illustrated in the figures are listed as under:
1) Circuit Breaker - MCCB (1)
2) Internal Accessories/full accessory, namely under voltage release and shunt release - (2)
- guiding profile of accessory housing (2a)
3) Main cover (3), which holds all internal accessories in cavities & facilitate integration of modules.
4) MCCB Front cover 4
5) Accessory actuator - 2b
6) MCCB Mechanism trip plate - 5a
In one implementation, the basic circuit breaker 1, as shown in figure 1, includes a front cover 4 pivoted with the main cover 3. The front cover 4 is demonstrated open and internal accessory 2 assembled into cavity 3a of main cover 3. The internal accessory 2 is integrated with main cover 3 with the help of guiding profile 2a and screwing 2e.
In one implementation, the cross-section of circuit breaker 1 is shown in the figure 3 with section line shown in the figure 2, is prior to insertion of the accessory 2 inside the main cover 3. The line of section is also drawn in figure 2 for reference of figures ahead.

In one implementation, the guiding profile 2a of under voltage release-shunt trip accessory unit 2 will first interact with the cavity 3a of main cover 3. The interaction of two profiles act as a locator for assembly and also as a guide till the accessory location is achieved prior to finalizing the fitment by screwing 2e. The interaction of 2a and 3a will ensure no movement in horizontal direction and allow to move only in Z direction.
In one implementation, the cross-section of MCCB 1 is shown in the figure 4 with section line shown in figure 2, wherein accessory actuator 2b with dual tripping cam profile cam 1 (2b-2) interacts with circuit breaker trip plate cam-1 (5a-l) during insertion and trips the mechanism, where actuator 2b cam-2 (2b-1) interacts with trip plate cam-2 (5a-2) only when accessory is mounted inside the MCCB refer figure 5. During tripping operation inside the MCCB cam-2 of actuator (2b-2) will interact with mechanism trip plate cam 2 (5a-2) at 15mm from the trip plate pivot and reduce initial high tripping force of mechanism, the required more travel for tripping of mechanism is achieved by means of changing of interaction point between trip plate and actuator from 15mm to 9mm. Thus cam 2 of both trip plate and actuator is designed in such a way that in in just touch condition both will interact at 15mm and reduce trip force and after travel that it will change its interaction point from 15mm to 9mm so that more travel can be achieved by keeping same liner travel of accessory actuator. (Refer figures 10, 11, 12).
In one implementation, the tripping slope 2b-ii of accessory actuator 2b utilize the movement induced by insertion force and hence rotates the trip plate 5a causing the MCCB mechanism 5 to trip, if it is in ON condition only.
Herein, the solution of the present invention provides safety to end customer from hazardous event of shock. If breaker is in ON status and the internal

accessories are energized through control circuit instead of main circuit, then there is a high chance to get electrocuted if customer tends to assemble the accessories when main circuit is energized. The invention provides sufficient safety to customer as it trips MCCB, preventing the hazardous event at customer end.
In one implementation, the cross-section of circuit breaker 1 is shown in the figure 5 with section line shown in figure 2, wherein the accessory unit 2 is located at final intended position with accessory actuator 2b moved completely to actuate the trip plate 5a of mechanism 5. The guiding profile 3a is received completely in the main cover cavity 3a ensuring no movement of the accessory. The fork of main mechanism 5 act as a reset component hitting the resetter 2c of the accessory unit 2 thus facilitating the resetting process.
As explained above, the trip status in MCCBs facilitate the customer to use various accessories through control circuits such that main circuit can be isolated from downstream appliances in case of emergencies or faults or over currents or over voltage or remote operation or any logic that customer wants. To normalize the system, resetting operation of mechanism 5 of MCCB 1 is to be done.
The operation of resetting mechanism 5 causes rotary motion of fork and resetter 2c of accessory. This rotation of resetter 2c with fork is converted into linear motion of accessory actuator 2b through interaction of pivot pin. This movement of accessory actuator 2b is in opposite direction of trip so that accessory unit 2 also get reset and latch 2d get locked with the resetter 2.
The accessory unit 2 is depicted in figure 6, wherein the tripping actuator 2b, guiding and locating profile 2a and tightening hardware 2e is explained.

The accessory tripping actuator 2b is depicted in figure 7, wherein the tripping slope 2b-ii, tripping profile 2b-i and resetting profile 2c is explained.
The cross-section of circuit breaker 1 is shown in figure 8 with section line shown in figure 2, wherein the accessory unit 2 is located at final intended position with accessory actuator 2b completely in reset state and MCCB is ON condition. The section in figure 8 explains the movement of tripping by the accessory action with the tripping profile. This rotates the mechanism trip plate in clockwise direction facilitating the mechanism to trip as shown in section of figure 9.
In one implementation, reference is made to figure 12, it shows cam 2 of trip plate and actuator reduces initial trip force and overcome required high trip travel of trip plate by keeping same liner travel of actuator.
Some of the non-limiting advantages of the present invention are as follows:
1. The cam 2 of both trip plate (5a-2) and Actuator (2b-2) being used for dual purpose to reduce initial high trip force and final high trip travel of trip plate by keeping same liner travel of accessory actuator.
2. The cam 2 of trip plate and actuator reduces initial trip force and overcome required high trip travel of trip plate by keeping same liner travel of actuator.
3. Direct interaction of accessory actuator 2b with mechanism trip plate 5a during accessory assembly and inside cover cavity ensures robust tripping arrangement.

4. Direct interaction of accessory actuator 2b with mechanism trip plate 5a during assembly and inside cover cavity avoids extra component in integration which reduces assembly time, product weight and high manufacturing cost of new component.
5. The slot arrangement between cover cavity (3a) and a guiding profile (2a) of the accessory housing ensures accessory position during and after assembly for smooth integration between trip plate and accessory actuator.
6. During normal ON/OFF operations of breaker it has been taken care that the actuator doesn't interfere with the mechanism trip plate and there is a considerable gap to avoid nuisance tripping.
Those skilled in the art will recognize other use cases, improvements, and modification to the embodiments of the present disclosure. All such improvements and other use-cases are considered within the scope of the concepts disclosed herein.

WE CLAIM :

1. A molded case circuit breaker (MCCB) comprising:
a cover cavity (3a) having one or more internal accessory unit (2);
at least a trip plate (5a); and
a dual cam arrangement between said trip plate (5a) and an accessory
actuator (2b), characterized in that said dual cam arrangement
comprising:
a cam profile 1 (5a-1, 2b-1) of said trip plate and said accessory actuator, wherein said cam profile (2b-l) of said accessory actuator interacts with said cam profile of said trip plate (5a-l) when said MCCB is in ON condition and during assembly of said one or more internal accessory inside said cover cavity;
a cam profile 2 (5a-2, 2b-2) of said trip plate and said accessory actuator, wherein during said MCCB tripping operation, said cam profile 2 of said accessory actuator (2b-2) interacts with said cam profile of said trip plate (5a-2) at an interaction point of 15 mm from a center of said trip plate (5a) to reduce a high tripping force.
2. The molded case circuit breaker as claimed in claim 1, wherein said cam profile 1 of said accessory actuator (2b-l) ensures said trip plate rotation in a clockwise direction to enable tripping of said MCCB.
3. The molded case circuit breaker as claimed in claim 1, wherein said accessory actuator (2b) is adapted to directly interact with trip plate (5 a) during accessory assembly and inside said cover cavity to ensure robust tripping arrangement.
4. The molded case circuit breaker as claimed in claim 1, further comprises a slot arrangement between said cover cavity and an accessory housing

guiding profile (2a) to ensure accessory position during and after assembly for smooth integration between said trip plate and said accessory actuator.
5. The molded case circuit breaker as claimed in claim 2, wherein a final rotational in said clockwise direction of said trip plate to trip said MCCB achieved by means of changing of said interaction point between said trip plate and said cam profile 2 of said accessory actuator (2b-2) from 15mm to 9mm.
6. A dual cam arrangement for a circuit breaker arranged between a trip plate (5a) and an accessory actuator (2b), wherein said dual cam arrangement comprising:
a cam profile 1 (5a-1, 2b-1) of said trip plate and said accessory actuator, wherein said cam profile (2b-1) of said accessory actuator interacts with said cam profile of said trip plate (5a-1) when said MCCB is in ON condition and during assembly of one or more internal accessory inside a cover cavity;
a cam profile 2 (5a-2, 2b-2) of said trip plate and said accessory actuator, wherein during said MCCB tripping operation, said cam profile 2 of said accessory actuator (2b-2) interacts with said cam profile of said trip plate (5a-2) at an interaction point of 15 mm from a center of said trip plate (5a) to reduce a high tripping force.