FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: CONTACT SYSTEM FOR USE IN DRAW-OUT TYPE MODULAR ASSEMBLY
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:

TECHNICAL FIELD OF THE INVENTION
This invention relates generally to a contact assembly for electrical device. More particularly the present invention relates to a contact system for use in draw-out type modular assembly.
BACKGROUND AND THE PRIOR ART
Conventional contact system has a bulk size and takes long time for assembly. The assembly is unique for a particular type of device. Some of the prior arts in the related field of invention are as follows:
US 5176529 provide a device for connecting control current lines in low voltage switchboard , plants. The device should allow the control current in a plug-in distribution board to be easily maintained up to a test position of the rack and to be cut beyond this position when the rack is drawn out. The device has two multipoint plugs with plugs and sockets, of which the first is rigidly linked to the rack and the other is movably mounted over a limited path on two guiding pins, the terminal cross-section of which is enlarged. In the test position they are locked in by elastic elements, ensuring complete contact between both multipoint plugs in this position when the rack is inserted. A plurality of control lines can be easily cabled with little attrition in a reduced space within a plug-in distribution board and a test position can be reached by drawing out the rack.
US 6806424 a novel connecting terminal (la) comprising at least one receiving means (2) or a base contact element (3) of a screw connection (4). The aim of the invention is to achieve a simple assembly and also to reduce the warehousing and production costs, while at the same time allowing the use of both screw and clamping technology. To achieve this, the screw connection (4) can be substituted by a module (6), which has spring-clamping elements (7) located therein and said module (6) can be engaged in a receiving shaft (5) of the connecting terminal (la). The warehousing and production costs are reduced for a connecting terminal (lb) comprising at least one spring-clamping element (7), by the provision of a receiving shaft (5), in which a module can

be engaged (6), said module containing spring-clamping elements (7).; The invention can be used in low-voltage switchgear, in particular contactors.
US 5594221 provides secondary disconnect arrangement, in the form of a plug connector attached to the sides of a high ampere-rated circuit breaker assembly, interacts with a receptacle connector attached to the inner side walls of a circuit breaker enclosure. Movement of the circuit breaker in and out of the enclosure automatically connects and disconnects the plug connector from the receptacle connector. Terminals arranged on the plug connector on one side of the circuit breaker connect with internal circuit breaker components for communication and control functions, while terminals arranged on the plug connector on the opposite side provide connection between the internal circuit breaker components and remote auxiliary devices.
US 5434369 provide an automatic secondary disconnect mechanism for an electrical switchgear apparatus having an enclosure and a removable circuit device is disclosed. According to a preferred embodiment, the automatic secondary disconnect mechanism comprises a guide rail mounted to the enclosure so as to extend substantially parallel to the racking motion of the circuit device; a slide member slidably mounted on the guide rail; apparatus for locking the slide member in place on the guide rail at a point corresponding to a test position of the circuit device; and apparatus for releasing the slide member when the circuit device reaches the test position from the disconnect position. One of a pair of mating secondary contact members is coupled to the slide member, while the other mating contact member is coupled to the circuit device. The mating secondary contact members automatically engage as the circuit breaker moves from the disconnect position to the test position, remain engaged and move together via the slide member as the circuit breaker moves between the test and connect positions, and automatically disengage as the circuit breaker moves past the test position toward the disconnect position.
US 6425556 provides a control and/or signaling device including a housing member and a head member, and which is intended for mounting in the mounting bore .of a mounting plate, a mounting wall or a like smaller than the head in the vicinity of the head. The housing member so that the control and/or signaling device can be attached through a nut member and using only one

hand. To this end, a resilient flexible material is placed in the transition area between the cylindrical housing and the head member wherein this flexible mass is applied according to a dual-component injection-moulding method. The housing member and the head member are made of hard resilient material that has a sealing function as well as fixation function optimised by rib-shaped segments.
US 6822173 provide contact element for an electrical switching apparatus is disclosed having a casing with a basis part and a cover part. Two electrical fixed contacts have connections for electrical conductors and disposed inside of the casing. An actuating tappet is supported over a first spring means in the casing and movable in an axial direction for receiving of a contact bridge, wherein the contact bridge serves for connecting or, respectively, interrupting the electrical connection between the two fixed contacts, wherein the actuating tappet is constructed such that the contact bridge can be disposed in two different positions having a distance from each other at the actuating tappet.
Conventional contact system has a large size and assembly requires a lot of time. Therefore there is need to have a contact system that can be easily assemble in less time. The present invention provides a Finger proof design and having Size almost half of conventional contact systems. Also it has a unique shape and configuration. It can be fitted along with all types of draw out type modules & switching devices.
OBJECTS OF THE INVENTION
A basic object of the present invention is to overcome the disadvantages/drawbacks of the known
art.
Another object of the present invention is to provide a contact system for use in draw-out type modular assembly.
Another object of the present invention is to absorb vertical tolerance.

Yet another object of the present invention is to provide a click arrangement for stacking contacts.
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
There is provided a contact system for use in draw-out type modular assembly.
According to one embodiment of the present invention, there is provided a contact system for use in draw-out type modular assembly comprising a plurality of male contacts and a plurality of female contact arranged at same horizontal level; a housing means accommodating said assembly; a plurality of position guides facilitating insertion of said housing means; wherein said system adapted to click fit a plurality of contacts and said male and female contacts adapted to absorb vertical tolerance.
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.
Fig 1-6 illustrates the two different pails of contact assembly namely, male and female contact assembly. It shows different views of the contact assembly.
Fig 7 illustrates disassembled view of Part 1 that is male contact assembly. As shown in fig it consist of two contact systems, housing for these contacts & two screws for wire lugs.

Fig 8 illustrates opening for inserting lug (IE), position guide (IF), slot for click fits (1M) and mounting projections (IN).
Fig 9 illustrates position guide (male) (1G), click fits (1H & IK) and contact support projections (IP).
Fig 10 illustrates Stacking of two male contact assemblies.
Fig 11 illustrates disassembled view of Part 2 that is female contact assembly. As shown in fig it consist of two contact systems, housing for these contacts & two screws for wire lugs.
Fig 12 illustrates opening for inserting lug (2E), position guide (female) (2F), slots for click fits (2M) and mounting projections (2N).
Fig 13 illustrates position guide (male) (2G), click fits (2H & 2K), contact support projections (2P).
Fig 14 illustrates Stacking of two female contact assemblies.
Fig 15 illustrates cylindrical contact (3A), flat surface (3B) and bent surface (3C).
DETAILED DESCRIPTION OF THE INVENTION
Accordingly the present invention relates to contact system used in draw-out type assemblies. Above mentioned electrical contact system is invented for giving control supply to the draw-out type of apparatus. Mainly it consists of two parts, Part 1 &Part 2 (as shown in Fig 1). Each part has its unique plug-in &sliding contact system which gives required contact pressure without spring because of its designed structure. The said contact system has inbuilt IP 20 protection.
This Contact system is so designed that there are two contact elements at same horizontal level which saves space & make it very compact. The contact system has inbuilt facility which can

take care of any vertical tolerances if exists, so no guiding is required. Contact system has facility of click fitting so you can stack any number of contacts as you want.
An object of the present invention is to provide a connecting terminal which is suitable for draw-out type assemblies. The present invention makes assembly of contact system simpler because of click fits provided & removal of spring which is used for contact pressure in conventional contact systems. Modules / trolleys (draw-out assemblies) used in switchgear & control gear assemblies are becoming more & more dense, as well need of number of auxiliary contacts are increasing, space inside the module is of great concern. The present invention makes contact system compact because of two contacts at same horizontal level saving space so same space can accommodate more number of auxiliary contacts. Termination of control cables at actual contacts is made easier by the use of simple screw clamping.
Single housing accommodates two different contact arrangements, making the assembly more compact. Click fit arrangement is provided in each housing to reduce the assembly time for making the stacks. Position guides (IF, 1G & 2F, 2G) are provided to facilitate proper insertion of housing assembly. Mounting projections (IN & 2N) are provided in housing for easy assembly on metal structure. Openings (IE & 2E) are provided in housing so that lugs can be inserted & clamped by using screws. Contact support projections (1P& 2P) are provided in housing to keep the contacts tightly placed. Total Assembly has in built IP 20 protection. Flat surface with bents (3B& 3C) are provided to give an extra strength and rigidity to thin contact material.
Cylindrical shaped (3A) design of male contact for easy insertion in female contact. Cylindrical shape male contact (3A) design is made for effective current distribution after analyzing the prominent "skin" & "proximity" effects. Flat surface with bents (4B &4C) are provided to give an extra strength and rigidity to thin contact material. Tulip shaped female contact (4A) design is made for effective current distribution after analyzing the prominent "skin" & "proximity" effects. Unique shape (4A) facilitates the easy insertion and guiding of male contact (3 A) while draw-in and draw-out of assembly. Contacts are assembled in the housing without use of any tools / hardware. Rigid bent surface (3C & 4C) of contact will reduce the pressure exerted by

external lugs and cables. Special Cylindrical contact (3A) and Tulip shaped contact (4A) are provided to absorb vertical tolerance of ±2 mm. Optimum contact pressure is generated without use of any kind of external spring. This is achieved with the unique design of contact. The special cross-section (3A & 4A) allows the optimization of expensive conducting material, to achieve an economic benefit.
Construction
Assembly can be characterized as consisting of two parts; Part 1 (Male contact assembly) and Part 2 (Female contact assembly) as shown in Fig. 1 to Fig. 6. When the assembly is in Isolated or Test position, as shown in Fig 1 to Fig. 3, the electrical separation is maintained. Part 2 is stationary &when Part 1 moves in the direction of arrow shown in Fig it comes in contact with Part 2 and continuity of current will be established. Fig. 4 to fig. 6 shows the contact assembly in Service position. Fig. 7 shows disassembled view of Part 1. As shown in fig it consist of two contact systems, housing for these contacts & two screws for wire lugs. Details of housing for above male contacts are as shown in Fig 8 & 9. It has facility of click fits for stacking purpose, position locator etc. Stacking of two male contact assemblies is as shown in Fig 10. When one assembly is pressed over another, whose position is guided by position locator, it gets stacked due to click fits provided. Any number of contact assemblies can be stacked. Fig. 11 shows disassembled view of Part 2. As shown in fig it consist of two contact systems, housing for these contacts & two screws for wire lugs. Details of housing for above female contacts are as shown in Figl2 &13. It has facility of click fits for stacking purpose, position locator etc. Stacking of two female contact assemblies is as shown in Fig 14. When one assembly is pressed over another, whose position is guided by position locator, it gets stacked due to click fits provided. Any number of contact assemblies can be stacked. Fig. 15 & 16 provides structure of both male & female contacts.
Part 1 (Male Contact Assembly):
Step l:Place the 1A & 1B in 1C as shown in Fig 7& tighten 1D in both the contacts.

Step 2: Place one male contact assembly over another, in such way that 1G gets inserted inside IF (see Fig. 8 & 9).
Step 3: Make a stack with click fit kind of joint using structure 1H & IK into slots 1M. Any number of contact assemblies can be stacked (see Fig. 10).
Step 4: The wiring of assembly can be done using wire lugs by inserting it in opening provided at IE.
Part 2 (Female Contact Assembly):
Step 1: Place the 2A & 2B in 2C as shown in Fig 11& tighten 2D in both the contacts.
Step 2: Place one female contact assembly over another, in such way that 2G gets inserted inside 2F (see Fig. 12 & 13).
Step 3: Make a stack with click fit kind of joint using structure 2FI & 2K into slots 2M. Any number of contact assemblies can be stacked (see Fig. 14).
Step 4: The wiring of assembly can be done using wire lugs by inserting it in opening provided at 2E.
Main Assembly:
Both the stacks (Male Contact Assembly and Female Contact Assembly) are placed as shown in Fig.l to Fig.6. When the draw-out assemblies move, both contact assemblies come in contact with each other automatically.
ADVANTAGES:
• Finger proof design.
• Size is almost half of conventional contact systems.

• Unique shape and configuration.
• Assembly is easy & requires less time as compared to present contact systems.
• Can be fitted Along with all types of draw out type modules & switching devices.
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 contact system for use in draw-out type modular assembly comprising:
a plurality of male contacts and a plurality of female contact arranged at same horizontal level;
a housing means accommodating said assembly;
a plurality of position guides facilitating insertion of said housing means;
wherein said system adapted to click fit a plurality of contacts and said male and female contacts adapted to absorb vertical tolerance.
2. System as claimed in claim 1 wherein said housing assembly further comprising a plurality of mounting projections facilitating substantially easy assembly on a metal structure.
3. System as claimed in claim 1 further comprising a plurality of lugs for wiring of said assembly.
4. System as claimed in claim 1 and 3 wherein said housing means having a plurality of openings adapted to insert a plurality of lugs and said lugs clamed using a plurality of screws.
5. System as claimed in claim 1 wherein said housing having a plurality of contact support projections to tightly fix said contacts.

6. System as claimed in claim 1 wherein said male contact having substantially cylindrical shape for insertion in said female contact.
7. System as claimed in claim 1 wherein said female contact having substantially tulip shape adapted for facilitating insertion and guiding of said male contact while draw in and draw out operation.
8. System as claimed in claim 1 wherein said male contact comprising an appropriate bent for reducing pressure exerted by external lugs and cables.
9. System as claimed in claim 1 wherein said female contact comprising an appropriate bent for reducing pressure exerted by external lugs and cables.
10. A contact system for use in draw-out type modular assembly as herein described and illustrated with reference to accompanying drawings.