DESC:TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to trip auxiliary contact actuation in the circuit breakers.
BACKGROUND AND THE PRIOR ART
Conventional Moulded Case Circuit Breakers (referred here after as MCCB or breaker) have provisions for Trip Auxiliary Contact (referred hereafter as TAC). TAC has a basic function of giving indication on transition of breaker to Trip condition from any other condition. TAC is generally a micro-switch with three terminals Common (C), Normally Closed (NC) & Normally Open (NO). During Normal conditions C and NC are connected and when micro-switch is actuated C & NC opens connecting C & NO.
MCCB has three stable states -
a. ON : Contacts Closed & Mechanism Latched
b. OFF : Contacts Open & Mechanism Latched
c. Trip : Contacts Open & Mechanism De-latched
Figure 1 to 5b in the present document disclose breaker mechanism as available at present.
For normal On / OFF operations of breaker the fork 23 has to be moved. By the movement of the fork Breaker can be set into ON & OFF conditions. Trip is a state of breaker in which the contacts are open and operating mechanism 2 trip plate 23 is de-latched. To bring the breaker to trip condition from ON condition the trip plate 23 has to be rotated so as to de-latch the latch bracket 24. The force required to de-latch the trip plate 23 is very less compared to force required to move the breaker fork from On to OFF condition. Also transaction from On to Trip is faster than On to OFF. This process of rotating the trip plate 23 and de-latching the breaker is called as tripping of the breaker.
Fig 4 a & b shows latched and de-latched conditions of the mechanism.
While tripping the breaker the latch bracket 24 is de-latched from the trip plate 23 which allows latch link 25 to move away from latch bracket. To reset the breaker the same latch link is moved back which forces latch breaker to go in latched condition again. breakers use this movement of latch link 25 to actuate the TAC 4.
The basic information regarding MCCB operation and trip auxiliary contact can be referred from following two patents based on Trip indication / Trip alarm.
Patent 1 : Electric Circuit Breaker with improved trip alarm (US 3562733)
Patent 2 : Mechanical bell alarm assembly for a Circuit Breaker (US 6882258 B2)
In conventional breakers the component used to actuate the TAC is mounted on latch link hinge point or it forms a rigid assembly with latch link. By this virtue the movement of the component is dependent upon the latch link movement.

OBJECTS OF THE INVENTION
One object of the invention is to overcome the disadvantages/drawbacks of the prior art.
A basic object of the present invention is to provide a trip alarm contact actuator mechanism for use in 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 arrangement for actuation of a trip alarm contact in circuit breaker, the arrangement comprising:
a latch link comprises an actuator interface pin, a pivot point and an actuator interface feature on actuator interface pin;
a trip alarm contact actuator comprises a pivoted profile, plurality of interaction means for interfacing with the latch link and the trip alarm contact,
wherein the trip alarm contact actuator pivoted connected with the latch link facilitating rotation of the actuator at a point by varying the actuator pivoted profile and the interaction means for the latch link, therefore providing movement of the actuator independent of movement of the latch link.
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.
Figure 1 illustrates a basic breaker assembly.
Figure 2 illustrates an auxiliary switch assembly.
Figure 3 illustrates an operating mechanism assembly.
Figure 4a illustrates an operating mechanism with trip plate latched.
Figure 4b illustrates an operating mechanism with Trip Plate de-latched.
Figure 5a illustrates an operating mechanism with trip plate latched.
Figure 5b illustrates an Operating Mechanism with Trip Plate de-latched and Latch link moved away from latch bracket.
Figure 6 shows angle of rotation of the latch link.
Figure 7 shows construction of the latch link and actuator for TAC.
Figure 8 shows actuator assembly in a breaker.
Figure 9 shows Breaker with TAC and actuator in Latched Condition.
Figure 10 shows Breaker with TAC and actuator in De-Latched Condition
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 numerals are used to depict the same or similar elements, features and structures.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
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 arrangement for actuation of a trip alarm contact in circuit breaker.
The present invention relates to arrangement for actuation of TAC 4 when breaker is in Trip condition. Conventional breakers have TAC actuator mounted on the same axis as that of Latch link. Due to this arrangement the angle of rotation of actuator depends completely on the angle of rotation of latch link. The angle of rotation of the latch link is determined by mechanism 2 and contact system 1 parameters. The angle a shown in fig. 5 shows the rotation angle of latch link.
The fig 6 shows the travel of the latch link during On / Off to Trip transition of the breaker. The angle a by which the latch link will rotate is defined by operating mechanism. So to get desired actuation movement of the actuator the TAC has to be mounted accordingly close or away from the latch link pivot point. Due to this feature the flexibility of mounting TAC in the breaker is lost.
The new actuator 5 designed is not a rigid component with latch link 25. The actuator 5 does not share common pivot axis with latch link 25. The actuator 5 is pivoted on three pole joining screw 11 of breaker. The pin 252 coming from the latch link 25 has interface with the link interface feature 52 of actuator 5 to transfer the rotation. This gives the flexibility of getting required actuation stroke from actuator 5 at any desired point by varying the actuator pivot point 51 and latch link interaction point 52 which is independent of the latch link pivot point 251. The actuator 5 is pivoted on a different axis than that of Latch link 25 and small portion of the pin 2521 protruding out from the latch link 25 interacts with the actuator latch link interface feature 52 to transfer the rotation of latch link to actuator. ,CLAIMS:1. An arrangement for actuation of a trip alarm contact in circuit breaker, the arrangement comprising:
a latch link comprises an actuator interface pin, a pivot point and an actuator interface feature on the actuator interface pin; and
a trip alarm contact actuator comprises a pivoted profile, plurality of interaction means for interfacing with the latch link and the trip alarm contact,
wherein the trip alarm contact actuator is pivotedly connected with the latch link facilitating rotation of the actuator at a point by varying the actuator pivoted profile and the interaction means for the latch link, therefore providing movement of the actuator independent of movement of the latch link.
2. The arrangement as claimed in claim 1, wherein the interaction means of the actuator interfaces with the pivot point of the latch link for transferring the rotation.

3. The arrangement as claimed in claim 1, wherein the actuator interface feature protruding out from the latch link for interacting with the interaction means of the actuator for transferring the rotation the rotation form the latch link to the actuator.

4. The arrangement as claimed in claim 1, wherein the actuator is pivoted on a different axis independent of axis rotation of the latch link.

5. The arrangement as claimed in claim 1, wherein the actuator is pivoted on a three pole joining screw of the circuit breaker.