FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - BUILT-IN SUPPORT ARRANGEMENT FOR A MODULAR INSULATED DRIVE SHAFT USING MECHANICAL ELEMENTS
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 circuit breakers. More particularly the present invention relates to an improved integrated drive shaft assembly for circuit breakers. The present invention relates to provide built-in support arrangement for a modular insulated drive shaft using mechanical elements.
BACKGROUND AND THE PRIOR ART
Circuit breaker typically serves two basic purposes. As a switching device: Switching On/Off during normal operating conditions for the purpose of operation and maintenance. As a protecting device: Tripping or Isolating by breaking the contacts interrupting the fault current during abnormal conditions such as short-circuit, overload and under voltage.
Circuit breaker consists of one or more electric poles, whose number determined by the application as single pole Circuit breaker, two pole Circuit breaker, three pole Circuit breaker, four pole Circuit breaker, five pole circuit breaker and so on. Each pole is made of a contact system and each contact system consists of a moving contact, a pair of fixed contacts, a pair of arc chutes assembly and Insulated drive shaft to rotate the moving contact to make connection and disconnection of current during ON-OFF operation. This insulated drive shaft along with the moving contacts is connected mechanically to the actuation mechanism of said circuit breaker.
In case of the circuit breaker contains two or more poles, IDS of each pole combine to form an improved drive shaft arrangement. An improved drive shaft arrangement is responsible to engage and transmit the actuation command from mechanism or any other driving member in any form engaged or connected and mechanically meshed by any means like gear or link or fasteners and likes to the moving contact of each and every pole.
In US 6960731, the drive shafts are assembled with an extra component known as coupler between the poles, which increases the number of components to achieve the required functions. In this solution the number of components increases with the number of poles increases in said

circuit breaker. With this there is a rotational lag that is inherently develops due to the number of components in engagement. More over this clearly has a negative impact on manufacturing and operating costs of the circuit breaker.
In US 5479143, the drive shafts are assembled and the motion is transmitted by means of a metal coupler. Provision of metal coupler can cause a potential danger of short-circuiting if not shielded/isolated properly during assembly.
In EP0555158 and US 6084489, the IDS of one pole is coupled together with other pole IDS by means of additional through Interconnection components such as bars or pins throughout the entire length of the shaft, so as to allow to transmit motion among the various poles of the circuit breaker. A conducting bar or pin running throughout the entire length between various poles may cause short-circuiting which is very dangerous.
In prior art, the IDS design explained have some drawbacks and critical aspects in terms of manufacturing and assembly. In all the above mentioned prior art, as the number and variety of components increases, manufacturing costs increases assembly and disassembly time increases.
Functionally, the rotational lag occurs due to the cumulative tolerance that sums up, between members of relatively moving components. This results in the low contact pressure in the poles at the extreme ends, which affects the performance of the breaker. In the above case, there is a clear negative impact on manufacturing and as well as assembly of IDS elements. These aspects have negative repercussions on the overall manufacturing costs and on the costs of the use and maintenance of the circuit breakers.
Thus there is a need to provide a IDS for a LV circuit breaker that allows to overcome not only the drawbacks described in case of above mentioned known shaft type, but also has an optimized detail structure and functional performance with improved built-in support using mechanical elements like bent pin and the likes that avoids the relative movement or the rotational lag.

Within the scope of the present aim, the shaft allows to eliminate non-uniformities in the transmission of motion, reduces relative torsional movement between the poles of the circuit breaker which is prevalent in existing solutions. The present invention ensures that there is uniform contact pressure across the poles of the breaker which is imperative to maintain a low temperature raise and to maintain good thermal resistance. Also, Contact Button erosion is reduced by maintaining uniformity of pressure at contacts and thereby increasing the life of the contact buttons.
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 an improved integrated drive shaft assembly for circuit breakers.
Other object of the present invention is to constrain the relative movement of end caps thereby providing for reduction in rotational lag.
Other object of the present invention is to provide to provide uniform contact pressure across the electric poles.
Yet another object of the present invention is to reduce relative torsional movement between said poles.
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.
There is provided an integrated drive shaft assembly.
According to one embodiment of the present invention, there is provided an improved integrated drive shaft assembly for circuit breakers comprising atleast a pair of drive shafts coupled to electric poles; atleast a pair of end caps (1) placed substantially on ends of said drive shaft, atleast one support means (2) for supporting said drive shaft in electric pole; atleast a pair of substantially bent pins (3) attached to a moving contact means (4) placed between said pair of end caps (1) adapted to assemble in a plurality of slots provided in said end caps; atleast one actuation means having a plurality of actuation receptacles; wherein said drive shaft adapted to provide substantially uniform contact pressure across the electric poles and substantially reduce relative torsional movement between said poles.
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.
In the appended drawings:
Figure 1 illustrates the various elements in the mechanical drive shaft assembly. End caps (1), with the built-in structural support (2) is placed in a such that their details face each other. Bent

pin (3), together with moving contact assembly (4) is placed between the two end caps as shown in fig. Bent pin(3) assembles with the end caps (1) in the corresponding slots provided for 7 seating, which increases the structural strength and reduces the torsional twist between two end caps.
Figure 2 illustrates the assembled built-in support shaft (5).
Figure 3 illustrates drive shaft assembly formed with three assembled shafts (5) placed in-line to each other.
Figure 4 illustrates the assembled three pole drive shaft (6).
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Accordingly in the present invention Fig 1 represents the various elements present in the shaft. Two end caps (1) comprise built-in support structures (2) having slots. Bent-pin (3), together with moving contact assembly (4) is placed between the two end caps as shown in fig 1. Bent pin(3) assembles with the end caps (1) in the corresponding slots provided for seating. The Shaft end caps constructed in such a way, that the basic structure is able to give built-in support to the profiled pin like bent pin and the same end cap can be flipped can placed to form the other end of the Insulated drive shaft (IDS). In this way, using single component of typical construction, allows to use single component to form multiple poles. With the unique structure, that provides built-in support for Profiled pin Like bent pin, increases the structural strength and reduces the torsional twist between two end caps as shown in figl.
Figure 2 represents the assembled built-in support shaft (5). Fig 3 represents drive shaft assembly. In a drive shaft assembly where two end caps/walls are placed on both sides of the drive shaft in such a way that the male projections and female cavities are facing outside. The mechanism cavity or any detail in the form of cavities or projections and etc. which acts as a receptacles for the actuation command flow is required for the mechanism link connection.

The actuation means is connected or engaged or linked to the drive shaft containing the actuation receptacles in any form like cavities or projections and etc., by means of a gear, or mechanical interference or screws arrangement or nut bolt arrangement or rivets or any other fastener means. The actuation means may transmit the motion from any direction, based on the arrangement, like top or bottom or co-axial or concentric or adjacent or lateral or parallel or from any co-ordinate plane.
Fig.3 represents the engagement of two IDS. In IDS to IDS assembly the end cap of one IDS faces the 180° horizontally flipped end cap of other IDS, as they are identical components. Now in this position, the male projections, faces female cavities and female cavities faces the male projections. During assembly, the male projection of one cap engages with the female cavity of the other in a mechanical fit like transition fit or interference fit or clearance fit and the likes, and vice versa. The overlap of male projection and female cavities form as robust assembly as possible to transmit the torque from one IDS to the other during operation.
Fig 4. Represents the assembled drive shaft for three pole, in the procedure described above.
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. An improved integrated drive shaft assembly for circuit breakers comprising:
atlest a pair of drive shafts coupled to electric poles;
atleast a pair of end caps (1) placed substantially on ends of said drive shaft,
atleast one support means (2) for supporting said drive shaft in electric pole;
atleast a pair of substantially bent pins (3) attached to a moving contact means (4) placed between said pair of end caps (1) adapted to assemble in a plurality of slots provided in said end caps;
atleast one actuation means having a plurality of actuation receptacles;
wherein said drive shaft adapted to provide substantially uniform contact pressure across the electric poles and substantially reduce relative torsional movement between said poles.
2. Assembly as claimed in claim 1 wherein said end caps comprising a male projection and a female cavity adapted to provide mechanical engagement of said drive shafts.
3. Assembly as claimed in claim 1 wherein said actuation means is connected to said drive shaft using a fastener means.
4. Assembly as claimed in claim 1 wherein said actuation means adapted to transmit motion from any coordinate plane.

5. Assembly as claimed in claim 1 wherein relative movement of said end caps are substantially constrained providing for reduction in rotational lag.
6. Assembly as claimed in claim 1 wherein said drive shafts are placed substantially in line to each other.
7. An improved integrated drive shaft assembly for circuit breakers substantially as herein described and illustrated with reference to accompanying drawings.