FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention - CRIMPING ARRANGEMENT FOR IMPROVED JOINT RESISTANCE
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 the field of switchgears. More particularly the present invention relates to a crimp assembly for use in switchgears and a method to form crimp assembly for use in switchgears. The invention provides an improvement in the crimping geometry thereby providing a reduced joint resistance and improved pull-out force of the braids,
BACKGROUND AND THE PRIOR ART
Crimping is the process of joining two conducting bodies by the process of forming. This creates a contact pressure between the mating contacts which is important to reduce the constriction resistance. Most switchgear devices use electrical braids for the purpose of conduction. Electrical braids typically consist of several thin strands of conducting material. The braids are connected to the part through several means and the air gap between the two parts is minimized to present a maximum contact area between the parts.
These crimped joints made by the process of crimping are generally used in automatic electrical systems to electrically interconnect between the terminals. These crimped joints used to join electrical connectors and terminals to the ends of wire in order to facilitate the connection of wires to various components.
US6658725 provides a method and an apparatus for forming a crimped joint in an electrical wire terminal. The apparatus forms a crimped joint and substantially simultaneously bends and/or twists the terminal and electrical wire about their respective longitudinal axes, effective to reduce electrical contact resistance within the formed joint.
Other conventional methods of crimping employ a crimper, a driving unit and an anvil. The anvil and crimper arranged movably in the direction of approaching and parting each other to crimp an end of electric wire to the crimping piece of terminal by inserting the end of electrical wire between crimp pieces. Also

conventional die cage assemblies are known to be used with crimping machine to crimp on a fitting on an end of a hose.
To create a conductive flexible coupling between two current carrying elements usually employs metallic foils using pressure welding and this is a very costly process. Metallic braids are used in several applications but fastening these braids with other parts is difficult and results in a large joint resistance. The braid experiences high forces when connected to mechanisms in switchgear. The braids show a tendency to leave the fastened joint of the terminal due to these forces. Therefore, in order to retain the joint and for the longevity of the joint it is imperative that the joint have a sufficient pull-out force. The braids and the other terminals are crimped with tools and devices for providing reduced joint resistance and increased pull out force of the braids. But using the present methods the desired pull-out resistance may not be achievable.
There is therefore a need to change the crimping profile to improve the crimping geometry for a reduced joint resistance of contacts and to increase the pull out forces of braids in a switchgear mechanism. Present invention provides a crimp assembly for use in switchgears and a method to form crimp assembly for use in switchgears. The invention provides an improvement in the crimping geometry thereby providing a reduced joint resistance and improved pull-out force of the braids.
OBJECT OF THE INVENTION
An object of the invention is to overcome the drawbacks / disadvantages of the prior art.
Another object of the present invention is to provide crimp assembly for use in switchgears.
Another object of the present invention is to provide a new feasible method of crimping which generates a pattern that delivers a low joint-resistance.

Another object of the present invention is to provide a crimp assembly having a reduced joint resistance.
Another object of the present invention is to provide an assembly that facilitates an improved pull out force of the braids.
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 aspect of the invention there is provided a crimp assembly.
Another aspect of the present invention is to provide a crimp assembly for use in switchgears, said assembly comprising a plurality of braids together defining a male part; a conductor means having a plurality of cavities defining a female part; a bridge means forming part of said conductor means; wherein said male part inserted to said female part whereby one end of said braid crosses dorsal face of said conductor means and pressed using a crimping tool thereby creating substantially flexible conductive coupling; wherein said crimping tool pressed to the conductor means with the braids inserted thereto whereby said bridge means and the braid deform to create a substantially v shaped crimping thereby joining the braid with the conductor means facilitating substantially reduced joint resistance and improved pull-out force of the braids.
Another aspect of the invention is to provide method to form crimp assembly for use in switchgears, said method comprising the steps of inserting a plurality of braids together defining a male part to a conductor means having a plurality of

cavities defining a female part; wherein one end of said braid crosses dorsal face of said conductor means and pressed using a crimping tool thereby creating substantially flexible conductive coupling; wherein said crimping tool pressed to the conductor means with the braids inserted thereto whereby said bridge means forming part of said conductor means and the braid deform to create a substantially v shaped crimping thereby joining the braid with the conductor means facilitating substantially reduced joint resistance and improved pull-out force of the braids.
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 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.
FIG 1 illustrates the generic view of the current carrying element/ conductor means before crimping.
FIG 2 illustrates top view of the current carrying element/conductor means before crimping.
FIG 3a (Left) illustrates a general view of the crimping tool. (Right) illustrates a view of the tool showing the penetration angle 'x', the width of the tool 'c', the length of the teeth 'b' and the radius of the tool 'R'
FIG 3b (Left) illustrates a Cross sectional view of the crimping profile of the current carrying element. (Right) illustrates Cross sectional view of the crimping

profile of the current carrying element showing the eccentricity of the penetration angle 'e', the diameter of the hole 'D', and the distance of the hole from the ends of the current carrying element 'a' and 'f.
FIG 4 illustrates a general view of the braid means after crimping.
FIG 5 illustrates a general view of the crimp assembly after crimping.
FIG 6 illustrates a view of the crimping process as the tool approaches the current carrying element/conductor means.
FIG.7 illustrates a view of the crimping process as the tool is inserted into the current carrying element/conductor means.
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 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 the invention presents a method to create crimped joint with a lower joint resistance. The invention proposes the use of electrical braids, consisting of plaited continuous strands of metal. These may be plated. The plaiting pattern may vary per use.
Most switchgear devices use electrical braids for the purpose of conduction. Electrical braid means typically consist of several thin strands of a conducting material. These braid means are connected to the part through several means. The air gap between the two parts is minimized and a maximum area of contact is presented between the two parts. The part consists of plural closed cavities with thin exposed bridging cross-sections/bridging means. The braid means is inserted into the cavity, such that one ends of the braid means crosses the dorsal face of the part and kept in place. The tool then forms the bridges and also the braids within. On post deformation the braid means take up a new geometry. The plaiting pattern

at the bridging cross section changes and this changed cross section determines the resistance of the joint now.
Present invention therefore provides a crimp assembly for use in switchgears. This assembly comprises a plurality of braids together defining a male part; a conductor means having a plurality of cavities defining a female part; a bridge means forming part of said conductor means; wherein said male part inserted to said female part whereby one end of said braid crosses dorsal face of said conductor means and pressed using a crimping tool thereby creating substantially flexible conductive coupling.
Further the crimping tool is pressed to the conductor means with the braids inserted thereto whereby said bridge means and the braid deform to create a substantially v shaped crimping thereby joining the braid with the conductor means facilitating substantially reduced joint resistance and improved pull-out force of the braids.
The elements of the present invention along with their reference numerals are as provided below:
Braid means (1)
Current Carrying element or conductor means (2)
Crimping tool (3)
Hole/cavities (4) in the current carrying element
Bridge means (5)
WORKING
The braid means are placed inside the holes of bottom terminal (refer fig. No 2). Once the braid means are placed inside the part, the crimping tool is used to press against the part. After pressing the part the crimping tool is withdrawn from the

part. Now the current flows from the braid to current carrying element. The total resistance of the current path is the summation of each of the resistances of the elements plus the joint resistance. Total resistance is obtained by adding together the resistance of the braid, joint resistance and the resistance of current carrying element. The crimping tool is pressed into the terminal with the braids inserted so that the material bridge and the braid deform to create the required geometry of braid.
ADVANTAGES
• The invention discloses a new means to achieve lower joint resistance between braids and a current carrying element. The benefits include a lower joint resistance and a lower watt loss,
• The benefits also include lower material flow in the dorsal plane, and hence feature retention in the said plane post forming.
• The new geometry improves the pullout force of the braid from the terminal.
EXPERIMENTAL DATA
Table below provides data for change in joint resistance with a change in the penetration angle-

85deg crimp (30 A, each pole)
1 2.5
2 2.5
3 2.26
4 2.22
5 2.24
6 2.35
7 2.3
8 2.55
Median 2.325
Avg 2.365

75deg (30 A, each pole)
1 2.6
2 2.3
3 2.4
4 2.6
5 2
6 2.7
7 2.7
8 2.8
Median 2.6
Avg 2.5125

70deg (30 A, each pole)
1 2.7
2 2,9
3 2.7
4 2.6
5 2.6
6 2.6
7 2.6
8 2,6
Median 2.6
Avg 2.6625
Table below provides for various pull-out forces for the changing penetration angles-

Pull-out force Penetration angle
90N 85 degrees
130N 7Sdegrees
160N 70degrees
Above data shows the millivolt drop between the joints for various crimping angles i.e 70, 75 and 85. 85 deg crimping angle shows the least millivolt drop (best mode of carrying out the invention).
V shape generated gives the advantages of reduction of resistance between the joints and improved pull out force of the braids. Crimping with V profile is used

for joining the braid with terminal and V shape helps to improve the efficiency of conduction by reducing the resistance.
Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein 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 embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.

WE CLAIM:
1. A crimp assembly for use in switchgears, said assembly comprising:
a plurality of braids together defining a male part;
a conductor means having a plurality of cavities defining a female part;
a bridge means forming part of said conductor means;
wherein said male part inserted to said female part whereby one end of said braid crosses dorsal face of said conductor means and pressed using a crimping tool thereby creating substantially flexible conductive coupling;
wherein said crimping tool pressed to the conductor means with the braids inserted thereto whereby said bridge means and the braid deform to create a substantially v shaped crimping thereby joining the braid with the conductor means facilitating substantially reduced joint resistance and improved pull-out force of the braids.
2. Assembly as claimed in claim 1 wherein each said braids consisting of a plurality of substantially thin strands of conducting material.
3. Assembly as claimed in claim 1 wherein said substantially v shaped crimping adapted to minimize air-gap between said male and said female part and providing substantially large contact area.
4. A method to form crimp assembly for use in switchgears, said method comprising the steps of:
inserting a plurality of braids together defining a male part to a conductor means having a plurality of cavities defining a female part; wherein one end of said braid crosses dorsal face of said conductor means and pressed

using a crimping tool thereby creating substantially flexible conductive coupling;
wherein said crimping tool pressed to the conductor means with the braids inserted thereto whereby said bridge means forming part of said conductor means and the braid deform to create a substantially v shaped crimping thereby joining the braid with the conductor means facilitating substantially reduced joint resistance and improved pull-out force of the braids.
5. A crimp assembly for use in switchgears as herein described and illustrated with reference to accompanying drawings.
6. A method to form crimp assembly for use in switchgears as herein described and illustrated with reference to accompanying drawings.