FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: MOLDED CASE CIRCUIT BREAKER INCORPORATING BRAIDLESS MOVABLE CONTACT ARM WITH FLIP ACTION
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 following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention relates to a Low voltage molded case current limiting circuit breaker. More particularly, the invention relates to a molded case circuit breaker incorporating braidless movable contact arm with flip action.
BACKGROUND OF THE INVENTION AND PRIOR ART
In molded case current limiting circuit breakers making and breaking of contacts happen by the movement of a moving contact connected to the terminal by a flexible conductor (braid). When an electrical connection is made between moving contact and stationary or fixed contact, current path is established. The arrangement of current path is such that, it provides enough force between the above said moving contact and fixed or stationary contact during over current for moving contact opening and hence limit the over current by phenomena of arc quenching.
Disadvantages of having braid:
Exposure of braid to high temperature will lead to loss of flexibility.
Since braids are made of multiple thin strands, at high currents braid will get stiff affecting flexibility..
The recent development of molded case circuit breakers is towards the compactness. This constrains the space available for the flexible braid for its free movement, which creates friction opposing free movement of braid thereby the movement of the moving contact is also affected. This may result in lesser opening of the moving contact.
Earlier attempts to avoid electrical contact braid are found in U.S. Patent Number 4733033, 3023292. According to these patents when moving contact repel opens; the mechanism should get tripped before the moving contact start

closing again to avoid arc restrike. So the mechanism trip signal should be quick enough for successful fault interruption and higher breaking capacity.
In U.S 4484164 the moving contact is held at the open position after it has completely opened by providing cam joint between moving contact and a stationary element. Thus it enhances the breaking capacity. But cam joint has drawbacks like
Friction
Wear and tear
Possibility of slip
Manufacturing difficulties of CAM profile
In U.S 5146194 the contact pressure between the moving contact and the stationary component to which the moving contact is pivoted is adjusted by screw tightening. So criticality should be maintained while tightening the screw for achieving a definite contact pressure between the moving contact and the stationary component to which the moving contact is pivoted.
Drawbacks of the prior art:
Possibility of slip
Manufacturing difficulties of complex CAM profile
Critical assembly
Present invention overcomes the drawbacks of the prior art:
By using spring flip mechanism slip possibility is
avoided.
Since placing the spring in proper orientation itself
determines the contact pressure between moving
contact and the stationary component to which the
moving contact is pivoted there is no critical assembly.

By avoiding CAM profile manufacturing difficulties are avoided.
OBJECTS OF THE INVENTION
One object of the present invention is to overcome the disadvantages / drawbacks of the prior art.
A basic object of the present invention is to provide a molded case circuit breaker incorporating braidless movable contact arm with flip action.
Another object of the present invention is to provide a reliable and efficient flip action that ensures the holding of the moving contact at open position after it has completely opened until the mechanism operates.
These and other advantages of the present invention will become readily apparent from the following detailed description taken 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.
According to one of the aspect of the present invention there is provided a molded case circuit breaker device having flip action, said device comprising:

a braidless movable contact arm;
a pair of stationary component having plural arms;
a rotor component operatively connected with said braidless movable contact arm;
a pair of braidless springs assembled in between the each arm of stationary
component and the rotor to ensure electrical connection between said braidless
movable contact arm and stationary component;
a contact spring assembly assembled in-between said braidless movable contact
arm and the rotor to provide the necessary contact pressure between the moving
contact button and the fixed contact button;
wherein said rotor and said stationary component is having a pre determined distance in-between them such that there is sufficient contact spring force to overcome the constriction force between said braidless movable contact and said stationary component at very high fault currents ensuring proper electrical connection between them.
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 DRAWING
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 front and full view of contact system of molded case current limiting circuit breaker.

Figure 2 illustrates assembly of the spring providing contact pressure between braidless moving contact and stationary component.
Figure 3a illustrates symmetrical cross sectional view of contact system at ON condition.
Figure 3 b illustrates symmetrical cross sectional view of contact system when the braidless moving contact is opening and crossing the dead center of the contact springs.
Figure 3c illustrates symmetrical cross sectional view of contact system after the braidless moving contact has completely opened and flipped.
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 present invention relates to a molded case circuit breaker device having flip action, the device comprising a braidless movable contact arm; a pair of stationary component; a rotor component operatively connected with the braidless movable contact arm, a pair of braidless springs assembled in-between the pair of stationary component to ensure electrical connection between the braidless movable contact arm and stationary component and a contact spring assembly assembled in-between the stationary component and the braidless movable contact arm.

The rotor and the stationary component is having a pre determined distance in-between them such that there is sufficient contact spring force to overcome the constriction force between the braidless movable contact and the stationary component at very high fault currents ensuring proper electrical connection between them.
The braidless movable contact arm and stationary component is made of copper and is a conductors.
The contact spring assembly determines contact pressure in between braidless movable contact and the stationary contact at ON condition.
The contact springs when current passing through the breaker increases to more than a definite value, the repulsion forces between the contacts overcome the spring force and thereby allowing the movable contact to rotate along the pivot of stationary component.
The contact springs crosses the dead centre making the movable contact to flip.
The contact springs crossed the dead centre the movable contact is held in the open position until the breaker mechanism operates.
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.
The present invention the braidless movable contact (2) is a single member pivoted on a stationary component (3) shown in fig 1.
Both these components are copper components and intended conductors. The electrical connection between these two components is ensured by assembly of the springs (5) (braidless springs) on both the sides of the stationary component (3) as shown in fig 2.
The spring (5) is assembled between the rotor component (4) and the stationary component (3). The distance between the rotor (4) and the stationary component (3) is designed such a way that there is sufficient spring force to overcome the constriction force between the braidless movable contact (2) and the stationary component (3) at very high fault currents ensuring proper electrical connection

between them. So by mere placing the spring in its position will determine its length in assembled condition thereby avoiding criticality in assembly.
The contact pressure between braidless movable contact (2) and the stationary contact (1) at ON condition is ensured by the contact spring assembly (6) as shown in fig 3a. These contact springs (7) are designed in such a way that when current passing through the breaker increases to more than a definite value, the repulsion forces between the contacts (1 and 2) overcome the spring force and thereby allowing the movable contact to rotate along the pivot (8) of stationary component (3).
During this course of time the contact springs (7) crosses the dead centre making the movable contact to flip as shown in fig 3b. Since the contact springs crossed the dead centre the movable contact is held in the open position until the breaker mechanism operates as shown in fig 3c.
The concept is the improved version of existing prior art to avoid the disadvantages of CAM connections and critical assemblies.
In the present invention the spring force offered by the braidless spring assembled between stationary contact arm and the rotor is determined by the distance between the rotor component and the stationary component which is ensured by the design (dimensions) of these components making the assembly simpler.
The reliable and efficient flip action of moving contact using spring dead centre mechanism for avoiding reclosure of moving contact also avoids the disadvantages of CAM connections.
Benefits:
• Simpler assembly.
• Reliable functionality, (no possibility of slipping)
• Easier manufacturability.

The feature in the present invention is achieving the objective of holding the braidless movable contact after it completely repel opens in the open position avoiding reclosure until mechanism operates , using reliable and efficient flip action of contact springs increasing contact mechanical life.

WE CLAIM:
1. A molded case circuit breaker device having flip action, said device
comprising :
a braidless movable contact arm;
a pair of stationary component having plural arms;
a rotor component operatively connected with said braidless movable
contact arm;
a pair of braidless springs assembled in between the each arm of stationary
component and the rotor to ensure electrical connection between said
braidless movable contact arm and stationary component;
a contact spring assembly assembled in-between said braidless movable
contact arm and the rotor to provide the necessary contact pressure
between the moving contact button and the fixed contact button;
wherein said rotor and said stationary component is having a pre
determined distance in-between them such that there is sufficient contact
spring force to overcome the constriction force between said braidless
movable contact and said stationary component at very high fault currents
ensuring proper electrical connection between them.
2. Device as claimed in claim 1 wherein said braidless movable contact arm is preferably made of copper.
3. Device as claimed in claim 1 wherein said stationary component is preferably made of copper.
4. Device as claimed in claim 1 wherein said contact spring assembly is adapted to determine contact pressure in between braidless movable contact and the stationary contact at ON condition .

5. Device as claimed in claim 1 wherein said contact spring being such that when current passing through the breaker increases to more than a definite value, the repulsion forces between the movable and stationary contacts overcome the spring force thereby allowing the movable contact to rotate along the pivot of stationary component.
6. Device as claimed in claim 1 wherein said contact springs crosses the dead centre making the movable contact to flip.
7. Device as claimed in claim 1 wherein said contact springs crossed the dead centre the movable contact is held in the open position until the breaker mechanism operates.
8. A molded case circuit breaker device having flip action as herein described and illustrated with reference to the accompanying drawings.