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: METHOD AND SYSTEM FOR DIFFERENTIAL METAL PLATING

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:

A) TECHNICAL FIELD

The present invention generally relates to differential metal plating and particularly relates to differential metal plating on a contact jaw assembly. The present invention more particularly relates to a differential selective metal plating on the contact jaw fingers.

B) BACK GROUND OF THE INVENTION
Over several years, the plating shops across the globe are trying to develop a differential silver plating process for reducing the silver plating cost and to improve the product function. In the current scenario, a method may not exist to perform differential silver plating on the contact jaw fingers with reduced silver plating cost. Further in first trial, the contact jaw fingers plating thickness was reduced from 10 μ to 5 μ thickness by applying grease. But, there was a functional problem in the trail process and a method was required to perform a differential silver plating process. Hence there is a need for a method and system to perform differential metal plating on the contact jaw fingers.
The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
C) OBJECT OF THE PRESENT INVENTION

The primary object of the present invention is to provide a system for performing a differential metal plating process on the contact jaw fingers.
Another object of the present invention is to provide a method for performing a differential metal plating process on the contact jaw fingers.

Yet another object of the present invention is that the differential metal plating process is performed on the contact fingers in two stages namely a jig plating stage and a barrel plating stage to achieve uniform silver plating.
Yet another object of the present invention is that the vat plating process is performed on a functional area of the one or more components in the fixtures hanged.

Yet another object of the present invention is that the barrel plating process is performed on the non- functional area of the one or more components.

Yet another object of the present invention is that the performance of metal silver plating is validated by conducting a plurality of tests.

Yet another object of the present invention is that the differential metal plating uses silver as a material.
These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION

The various embodiments of the present invention provide a system for performing differential metal plating on contact fingers. The system comprising a partition plate, a handle mounted on the partition plate, a plurality of side plates, and a clamp to hold the plurality of side plates. The differential metal plating is performed on the contact fingers in two stages namely a jig plating stage and a barrel plating stage to achieve uniform silver plating. Here the handle is made of stainless steel and the clamp is of a poly propylene material.

According to another embodiment of the present invention, a method for performing differential metal plating on contact fingers includes racking one or more components in a fixture, assembling the one or more components in the fixture, and hanging the fixtures on a vat to perform a vat plating. The method further includes performing the vat plating on a functional area of the one or more components in the fixtures hanged.

According to one embodiment of the present invention, the system further includes a stainless steel support and a stainless steel rod.
According to one embodiment of the present invention, the jig plating stage comprises providing a metal coating of an 8 micron thickness on a functional area of the contact fingers.
According to one embodiment of the present invention, the barrel plating stage comprises a step of providing a metal coating of 2 micron thickness on the contact fingers.

According to one embodiment of the present invention, the method includes unloading the one or more components from the vat plating fixtures.

According to one embodiment of the present invention, the method includes performing a barrel plating on the non- functional area of the one or more components.
According to one embodiment of the present invention, the performance of the circuit breakers with differential metal plating is validated by conducting a plurality of tests. The plurality of tests include a rack in rack out test , a environmental Test , a temperature Rise Test , a heat run test, and a short time withstand Test.
According to one embodiment of the present invention, the differential metal plating uses silver as a plating material.
These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

E) BRIEF DESCRIPTION OF THE DRAWINGS

The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiments and the accompanying drawings in which:

FIG. 1 illustrates a front side perspective view of a differential plating fixture, according to one embodiment of the present invention.

FIG. 2 illustrates a side perspective view of a differential plating fixture, according to one embodiment of the present invention.

FIG.3 illustrates a top side perspective view of a differential plating fixture, according to one embodiment of the present invention.

FIG.4 illustrates a front side perspective view of a contact finger with differential metal plating on functional areas, according to one embodiment of the present invention.
FIG.5 illustrates a detailed front side view of differential metal plating on a contact fingers according to one embodiment of the present invention.

Although the specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.

F) DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, a reference is made to the accompanying drawings that form a part hereof and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

The various embodiments of the present invention provide a system for performing differential metal plating on contact fingers. The system comprising a partition plate, a stainless steel handle mounted on the partition plate, a plurality of side plates, and a poly propylene clamp holding the plurality of side plates. The differential metal plating is performed on the contact fingers in two stages namely a jig plating stage and a barrel plating stage to achieve uniform silver plating.

Another embodiment of the present invention describes a method for performing differential metal plating on contact fingers. The method includes racking one or more components in a fixture, assembling the one or more components in the fixture, hanging the fixtures on a vat to perform a vat plating. The method further includes performing the vat plating on a functional area of the one or more components in the fixtures hanged.

According to one embodiment of the present invention, the system includes a stainless steel support and a stainless steel rod.

FIG. 1 illustrates a front side perspective view of a differential plating fixture, according to one embodiment of the present invention and FIG. 2 illustrates a side perspective view of a differential plating fixture, according to one embodiment of the present invention. FIG.3 illustrates a top side perspective view of a differential plating fixture, according to one embodiment of the present invention. With respect to FIG.1, FIG.2 and FIG.3, the differential plating fixture includes a partition plate 102, a handle 104, a screw 106, a clamp 202, a stainless steel support 204, a plurality of side plates 206, a stainless steel rod 302, a screw 304 and a wing nut 306.
The handle 104 is mounted on the partition plate 102 and the handle 104 is fixed to the partition plate 102 using the screw 106.The clamp 202 holds the plurality of side plates 206 along with the stainless steel support 204. The stainless steel rod 302 is arranged horizontally using the screw 304 and the wing nut 308. The differential metal plating is performed on the contact fingers in two stages namely a jig plating stage and a barrel plating stage. The differential metal plating process is done on the contact fingers to achieve a uniform silver plating throughout the components.

FIG.4 illustrates a front side perspective view of a contact finger with differential metal plating on functional areas, according to one embodiment of the present invention. FIG.5 illustrates a detailed front side view of differential metal plating on contact fingers, according to one embodiment of the present invention. With respect to FIG.4 and FIG.5, the differential metal plating includes one or more functional areas 402 and non-functional areas 404 on contact jaw fingers. The differential metal plating uses silver as a metal for surface plating. The differential metal plating is performed on the contact fingers in two stages to achieve uniform metal plating. The two stages include jig plating stage and a barrel plating stage.

In the jig plating stage, the functional areas 402 of the contact fingers are coated with a silver plating of 8 micron thickness as shown in FIG.5. The plurality of contact fingers are racked in a fixture. Further the plurality of contact fingers are assembled in the fixtures and are hanged on a vat to perform metal plating. The metal plating is then performed on functional areas 402 of the plurality of contact fingers arranged in the fixtures hanged on to the vat.

In the barrel plating stage, the plurality of contact fingers is unloaded from the vat plating fixtures. Further, barrel plating is performed on the non- functional areas 404 of the plurality of contact fingers. The barrel plating provides a silver plating of 2 micron thickness on the non- functional areas 404 of the contact fingers as shown in FIG.5. The performance of differential selective silver plating is validated by conducting a plurality of tests. The plurality of tests are a rack in rack out test , a environmental test , a temperature rise test , a heat run test , a short time withstand test.
G) ADVANTAGES OF THE INVENTION

The various advantages of the present embodiment include consumption of less time for differential metal plating on the contact jaw fingers in a contact assembly. . Further the performance of differential metal plating is validated by conducting a plurality of tests such as a rack in rack out test , a environmental Test , a temperature Rise Test , a heat run test , a short time withstand Test. The performance of the circuit breakers using the differential silver plated contact fingers is high.

Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.
We CLAIM:
1. A system for performing a differential metal plating on contact fingers, the system comprising :
a partition plate;
a handle mounted on the partition plate;
a plurality of side plates; and
a clamp to hold the plurality of plates.
Wherein the differential metal plating is performed on the contact fingers in at least one of a jig plating stage and a barrel plating stage to achieve uniform metal plating.

2. The system according to claim 1, further comprises a stainless steel support and a stainless steel rod.

3. The system according to claim 1, wherein the differential metal plating includes silver as a plating metal. .

4. The system according to claim1, wherein the jig plating stage provides a silver plating of 8 micron thickness on functional areas of the contact fingers.

5. The system according to claim1, wherein the barrel plating stage provides a silver plating of 2 micron thickness on the contact fingers.
6. A method for performing differential metal plating on contact fingers, the method comprising:
racking one or more components to be plated in a fixture;
hanging the fixture on a vat; and
performing a vat plating on a functional area of the one or more components arranged in the fixtures.

7. The method according to claim 6, further comprises unloading the one or more components from the fixtures.

8. The method according to claim 6, further comprises performing a barrel plating on the non- functional area of the one or more components.

9. The method according to claim 6, wherein the differential metal plating includes selective silver plating.