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 - MODULAR MECHANICAL ENGAGEMENT FOR INSULATED
DRIVE SHAFT

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 an improved drive shaft arrangement of Low Voltage current limiting circuit breaker and the likes. Particularly the present invention relates to an improved drive shaft arrangement which is commonly used in the above said circuit breaker and the likes to receive, supply, protect and isolate the current supply in an electrical circuit. More particularly the present invention relates to an improved drive shaft arrangement which is formed with mechanical engagement of one or more insulated drive shaft in circuit breaker.

BACKGROUND AND PRIOR ART OF THE INVENTION

In prior art, the Insulated Drive Shaft (IDS) design explained have some drawbacks and critical aspects in terms of manufacturing and assembly.

US 6,960,731 discloses a rotating contact supporting shaft for a low-voltage power circuit breaker, whose particularity consists of the fact that it has a modular structure that comprises, along the rotation axis, at least one first and one second supporting module (10, 20), each module being functionally coupled to at least one corresponding moving contact (3) of the circuit breaker and being provided respectively with first and second means (22) for connection to at least one first interconnection module (30); the first interconnection module is interposed between the first and second supporting modules and is provided with third and fourth connection means (31) that are suitable to be coupled respectively to the first and second connection means; the coupling between the first and third connection means and between the second and fourth connection means allows the functional connection between the first and second supporting modules and the direct structural connection of the interconnection module to the first and second supporting modules.

US 5479143 discloses Each breaking module is formed by a parallelepipedic monoblock cartridge made of plastic material, housed in the corresponding compartment of the base plate, said cartridge housing at least a stationary contact, an arc extinguishing chamber, and a pair of connecting strips for connection to a terminal and to the trip module of the same pole. A mechanical actuation module constituted by the switching bar and mechanism assembly, is securely united to the cover. The rotary trip bar is supported by clipping means, arranged on the bottom face of the cover.

US 6084489 discloses the circuit breaker is characterized by separable contacts operable between a closed and an open position a contact arm having a latching surface and a latch arranged to engage the latching surface when the contacts are blown-open under short-circuit conditions. The arrangement of the latch allows for a positive lock under high magnitude short circuit levels while minimizing the force required by a mechanism to unlock the arm.

In first known type of solution, (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 second known type of solution, (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. With this there is a rotational lag that is inherently develops due to the number of components in engagement.

In third known type of solution, (EP0555158, 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. With this there is a rotational lag that is inherently develops due to the bending or deformation of the pins.

The disadvantages of the above mentioned prior art is that 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 present invention the IDS arrangement for the Low voltage circuit breaker and the likes, and the similar arrangements and any such citations here after assumed as the part of the same invention, that allows to overcome not only the drawbacks described in case of above mentioned known shaft types, but also has an optimized detail structure and functional performance with reduced number of components.

Within the scope of the present aim, the shaft allows to eliminate completely or reduce significantly, non-uniformities in the transmission of motion among various poles of the circuit breaker which is prevalent in existing solutions.

This will ensure 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. Contact Button erosion is reduced by maintaining same pressure and thereby increasing the life of the contact buttons.

OBJECTS OF THE INVENTION

A basic object of the present invention is to overcome the drawbacks/disadvantages of the prior art.

One of the main objects of the invention is to provide a unique mechanical detailing on the IDS end cap which is the meshing surface to the other IDS of similar detailing.

Another object of the present invention lies in achieving modularity, improving functionality and increasing the ease of assembly by using only one variety of components for IDS construction.

Yet another object of the present invention is to provide a way of reducing the manufacturing cost by splitting the IDS into two end caps which are identical, with the moving contact assembly.

Yet another object of the present invention is to provide a way that eliminates the variety and number of components there by reducing assembly time and increasing manufacturing ease.

Yet another object of the present invention lies in maintaining uniform contact pressures across the poles by reducing the number of mechanical engagements.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided an improved drive shaft arrangement in a circuit breaker and the likes, said arrangement comprising
Plurality of identical drive shaft assembly, said each assembly comprising
a pair of drive shaft means;
Moving contact assembly operatively placed in-between said pair of drive shaft means;
pair of wall means securing said drive shaft means, said walls comprising an outer wall and an inner wall; wherein said walls are identical to each other;
Wherein said outer wall comprising:
Plurality of projections substantially located on the outer wall;
Plural cavities substantially located on the outer wall adapted to get engaged with said plurality of projection and
Plurality of mechanism or actuation receptacle detail substantially located on the outer wall adapted for mechanism or actuation engagement or any kind of link connection;
Wherein said improved drive shaft arrangement is defined by engaging each drive shaft assembly with one another in a unique mechanical arrangement adapted to connect and /or disconnect the current flow in circuit breaker;
wherein said unique mechanical arrangement is defined by placing one or more drive shaft assemblies coaxially and oriented such that the projections on drive shaft assembly faces the cavities on next immediate drive shaft assembly and cavities on drive shaft assembly faces the projections on next immediate drive shaft assembly.

According to another aspect of the present invention there is provided a drive shaft assembly, said assembly comprising
a pair of drive shaft means;
Moving contact assembly operatively placed in-between said pair of drive shaft means;
pair of wall means securing said drive shaft means, said walls comprising an outer wall and an inner wall; wherein said walls are identical to each other;
Wherein said outer wall comprising:
Plurality of projections substantially located on the outer wall;
Plural cavities substantially located on the outer wall adapted to get engaged with said plurality of projection and
Plurality of drive command receptacles in any form like cavities, projections, gear teeth and the likes which aides for receiving actuation from any actuation means or mechanism substantially located on the outer wall adapted for connection.

According to a further aspect of the present invention there is provided a circuit breaker system, said system comprising
plurality of pressure enclosure substantially enclosing said contact system assembly , said enclosure comprising
a contact system , said contact system comprising
a pair of fixed contacts;
arc chute assembly;
a moving contact ;
a drive shaft assembly adapted to rotate the moving contact to make connection and disconnection of current during ON-OFF operation;
an actuation means selectively comprising a mechanism or a driver motor or any other motion or actuation command transmission arrangement transmitting the motion or actuation or drives the drive shaft, located on top or bottom or coaxial or concentric or adjacent or lateral or parallel or located in any co-ordinate plane with respect to the said drive shaft of one of the said enclosure; 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.
wherein each enclosure comprising a drive shaft assembly, such that the drive shaft assembly engaging with another drive shaft assembly that is placed in another enclosure to define an unique mechanical arrangement adapted to engage and transmit the actuation command from actuation mechanism to the moving contact of each and every enclosure.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is related to an improved drive shaft arrangement of Low Voltage current limiting circuit breaker and the likes, which are commonly used to receive, supply, protect and isolate the current supply in an electrical circuit. 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 and all with neutral pole and with-out neutral pole included. 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 means or mechanism and the likes in any form 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 this invention, an improved drive shaft arrangement is built by engaging each IDS with one another in a unique mechanical arrangement. The mechanical engagement is achieved from the unique features that the end cap contains, on the meshing surface of the drive shaft. Constructing an improved drive shaft arrangement, which may contain two or more IDS, by using only one variety of component made of any plastic material or metal and any insulated and un insulated material and the likes and repeating it in designated order.

MAIN FEATURES OF THE INVENTION

Innovation lies in the unique mechanical detailing on the IDS end cap which is the meshing surface to the other IDS of similar detailing.

Innovation lies in the way of achieving modularity, improving functionality and increasing the ease of assembly by using only one variety of components for IDS construction.

Innovation lies in the way of reducing the manufacturing cost by splitting the IDS into two end caps which are identical, with the moving contact assembly.

Innovation lies in eliminating the variety and number of components there by reducing assembly time and increasing manufacturing ease.

Innovation lies in maintaining uniform contact pressures across the poles by reducing the number of mechanical engagements.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

Fig. 1 illustrates a contact system.
Fig. 2 illustrates an exploded view of a Drive shaft .
Fig 3 illustrates drive shaft assembly.
Fig 4 illustrates the engagement of 2 IDS.
Fig. 5A illustrates the assembly sequence of the main shaft
Fig. 5B illustrates the engaged drive shaft together with actuation mechanism
Fig. 6 illustrates the electrical poles with (19) main shaft

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWING

The working is explained with reference to the figures 1-6.

As represented in Fig. 1, a contact system consists of a moving contact (1), a pair of fixed contacts (2), a pair of arc chutes (3) and an insulated drive shaft (4).

Contact system elements assembled in a two pressure enclosure is termed as an electrical pole (5).
Fig. 2 is an exploded view of a Drive shaft assembly. Drive shaft assembly consisting of a moving contact (1) which is placed along with plurality of energy storing elements of any kind like compressing spring or extension spring or coil spring or leaf spring or cam and the likes (8) distributed on one side or either side of the moving contact to aid its movement. This assembly also consists of plurality of supporting pins or structure (9) placed perpendicular to moving contact, out of which a pair is used to hold the energy storing elements in place and a pair of pins or structure is used as a stopper for the moving contact during its operation.

The entire assembly is placed in-between two identical end caps/walls made of any plastic material or metal and any insulated and un insulated material and the likes and repeating it in designated order which forms the outer walls (6) and inner walls (7) of the assembly.

Fig 3 represents drive shaft assembly. In a drive shaft assembly (4) where two end caps/walls are placed on both sides of the drive shaft in such a way that the male projections (10) and female cavities (11) are facing outside. The mechanism cavity (12) (13) 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 is 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. 4 represents the engagement of 2 IDS.
In an IDS (4) to IDS (4) 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 (10), faces female cavities (11) and female cavities (11) faces the male projections (10).

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. 5A explains the assembly sequence of the main shaft. The Figure also shows one or more IDS placed coaxially and oriented such that the male projections and the female cavities on (6) of IDS (4) faces the female cavities and male projections on (6) of next immediate IDS (4). Similarly, the male projections and the female cavities on (6) of next IDS (4) face the female cavities and male projections on (6) of next immediate IDS (4). (12) (13) represents the receptacle details in the form of cavities or projections and etc. provided for mechanism or any actuation link connection. The figure also represents the assembly of actuation mechanism or any driving means or the motion transmission means (15) on the IDS. The Means (14) which may be a connector in any form of a driving means like link or gear or mechanical meshing and the likes from the mechanism or any actuation means are used to rivet or fasten or meshed or engaged on the detail (12) (13) provided in two end caps (6) of any one of the IDS (4) in an improved drive shaft arrangement which takes the input from knob or any actuation inputting interface (16) rotation or linear movement or parallel movement or perpendicular movement or any movement of any kind and connects/disconnects the current flow.

Fig. 5B, the engaged drive shaft together with actuation mechanism where one or more individual insulated drive shaft forms an improved drive shaft arrangement by the engagement of male projections into female cavities and female cavities into male projections and command flow from actuation mechanism is transmitted through the engagement to the poles by IDS engagement.

Fig. 6 represents the electrical poles with (19) an improved drive shaft arrangement consisting of one or more IDS (4), actuation mechanism (15) and contact system elements with line end terminal (18) and load end terminal (18). As represented, the actuation mechanism is placed on the top of any one of the pole and the links are connected to the details provided (12) (13) on the IDS through the cavity (17) provided in the contact system cassettes.

The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

WE CLAIM:

1. An improved drive shaft arrangement in circuit breaker and the likes, said arrangement comprising
plurality of identical drive shaft assembly , said each assembly comprising
a pair of drive shaft means;
moving contact assembly operatively placed in-between said pair of drive shaft means;
pair of wall means securing said drive shaft means, said walls comprising an outer wall and an inner wall; wherein said walls are identical to each other;
wherein said outer wall comprising:
plurality of projection means substantially located on the outer wall;
plural cavities substantially located on the outer wall adapted to get engaged with said plurality of projection and
Wherein said improved drive shaft arrangement is defined by engaging each drive shaft assembly with one another in a unique mechanical arrangement adapted to connect and /or disconnect the current flow in circuit breaker;
wherein said unique mechanical arrangement is defined by placing one or more drive shaft assemblies coaxially and oriented such that the projection means on drive shaft assembly faces the cavities on next immediate drive shaft assembly and cavities on drive shaft assembly faces the projections on of next immediate drive shaft assembly.
2. Arrangement as claimed in claim 1 wherein said projection means is selectively circular or polygonal.
3. Arrangement as claimed in claim 1 comprising one or more projection means.
4. Arrangement as claimed in claim 1 wherein said moving contact assembly comprising
a moving contact;
plurality of energy storing element substantially placed on either side of said moving contact adapted to aid in movement and
plurality of supporting structures substantially placed perpendicular to said moving contact adapted to assist said moving contact in operations.
5. Arrangement as claimed in claim 1 wherein said outer wall of drive shaft assembly faces about 180 ˚ horizontally flipped of another outer wall of drive shaft assembly.
6. Arrangement as claimed in claim 1 wherein said drive shaft assembly is mechanically connected to actuation means selectively comprising a mechanism or a driver motor or any other motion or actuation command transmission arrangement transmitting the motion or actuation or drives the drive shaft of the circuit breaker and the likes by said lower link.
7. Arrangement as claimed in claim 6 wherein said actuation means optionally comprising a connector in any form of a driving means like link or gear or mechanical meshing and the likes.
8. Arrangement as claimed in claim 1 wherein said actuation mechanism further comprising a knob or any command inputting interface operatively connected with said mechanism adapted to provide input.
9. Arrangement as claimed in claim 4 wherein said plurality of structures comprising a pair of pin means adapted to act as a stopper for said moving contacts during its operation.
10. Arrangement as claimed in claim 1 wherein said plurality of projections comprising a pair of male projections substantially facing outside said outer wall.
11. Arrangement as claimed in claim 1 wherein said plurality of cavities are selectively circular or polygonal.
12. Arrangement as claimed in claim 1 wherein said plurality of cavities comprising a pair of female cavities substantially facing outside said outer wall.
13. Arrangement as claimed in any of the preceding claims wherein said male projections face the female cavities and said female cavities face the male projections.

14. Arrangement as claimed in claim 1 wherein said unique mechanical arrangement is adapted to transmit the rotational torque or any motion command in any form from one drive shaft assembly to another.
15. Arrangement as claimed in any of the preceding claims wherein said drive shaft is insulated.
16. A drive shaft assembly , said assembly comprising
a pair of drive shaft means;
moving contact assembly operatively placed in-between said pair of drive shaft means;
pair of wall means securing said drive shaft means, said walls comprising an outer wall and an inner wall; wherein said walls are identical to each other;
wherein said outer wall comprising:
plurality of projections substantially located on the outer wall;
plural cavities substantially located on the outer wall adapted to get engaged with said plurality of projection and
plurality of mechanism cavity substantially located on the outer wall adapted for mechanism or any other form of actuation link connection.
17. Assembly as claimed in claim 16 wherein said moving contact assembly comprising :
a moving contact;
plurality of energy storing element substantially placed on either side of said moving contact adapted to aid in movement and
plurality of pin means substantially placed perpendicular to said moving contact adapted to assist said moving contact in operations.
18. Assembly as claimed in claim 17 wherein said energy storing element selectively comprising compression spring or extension spring or coil spring or leaf spring or cam and the likes.

19. Assembly as claimed in claim 16 wherein said plurality of projections comprising male projections substantially facing outside said drive shaft.
20. Assembly as claimed in claim 19 wherein said male projections are selectively circular or polygonal.
21. Assembly as claimed in claim 16 wherein said plurality of cavities comprising female cavities substantially facing outside said drive shaft.
22. Assembly as claimed in claim 21 wherein said female cavities are selectively circular or polygonal.
23. Assembly as claimed in claim any of the preceding claims wherein said male projections face the female cavities and said female cavities face the male projections.
24. Assembly as claimed in any of the preceding claims wherein said drive shaft is insulated.
25. A circuit breaker system, said system comprising
plurality of pressure enclosure substantially enclosing said contact system assembly , said enclosure comprising
a contact system , said contact system comprising
a pair of fixed contacts;
arc chute assembly;
a moving contact ;
a drive shaft assembly adapted to rotate the moving contact to make connection and disconnection of current during ON-OFF operation;
an actuation means selectively comprising a mechanism or a driver motor or any other motion or actuation command transmission arrangement transmitting the motion or actuation or drives the drive shaft, located on top or bottom or coaxial or concentric or adjacent or lateral or parallel or located in any co-ordinate plane with respect to the said drive shaft of one of the said enclosure; said actuation means being connected or engaged or linked to the drive shaft, containing the actuation receptacles in any form like cavities or projections and the like, by means of a gear, or mechanical interference or screws arrangement or nut bolt arrangement or rivets or any other fastener means ;
wherein each enclosure comprising a drive shaft assembly, such that the drive shaft assembly engaging with another drive shaft assembly that is placed in another enclosure to define an unique mechanical arrangement adapted to engage and transmit the actuation command from actuation mechanism to the moving contact of each and every enclosure.
26. System as claimed in claim 25 wherein said drive shaft along with the moving contact is connected mechanically to the actuation mechanism of said circuit breaker.
27. System as claimed in claim 25 wherein said enclosure is electrical poles.
28. System as claimed in claim 25 wherein said plurality of drive shaft assembly , said assembly comprising
a pair of drive shaft means;
moving contact assembly operatively placed in-between said pair of drive shaft means;
pair of wall means securing said drive shaft means, said walls comprising an outer wall and an inner wall; wherein said walls are identical to each other.
29. System as claimed in claim 21 wherein said outer wall comprising:
plurality of projection substantially located on the outer wall ;
plurality cavities substantially located on the outer wall;
plurality of mechanism cavity for engaging mechanism or actuation receptacle detail substantially located on the outer wall.
30. System as claimed in claim 29 wherein said plurality of projections are selectively circular or polygonal.
31. System as claimed in claim 29 wherein said plurality of cavities are selectively circular or polygonal.
32. System as claimed in claim 29 wherein said drive shaft is insulated.
33. An improved drive shaft arrangement in a circuit breaker as herein substantially described and illustrated with reference to the accompanying drawings.
34. A drive shaft assembly as herein substantially described and illustrated with reference to the accompanying drawings.
35. A contact system in a circuit breaker as herein substantially described and illustrated with reference to the accompanying drawings.