FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: AN IMPROVED MECHANISM FOR MOUNTING OF BREAKER SECONDARY ISOLATING CONTACTS IN MOUNTING BLOCK OF CIRCUIT BREAKER
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 mounting of the breaker secondary isolating contact (SIC) in the circuit breaker. More particularly, the present invention relates to an improved mechanism for the independent positioning/mounting of secondary isolating contacts (SIC) which also called as auxiliary type of contacts in the mounting block of circuit breakers.
BACKGROUND AND PRIOR ART OF THE INVENTION
A circuit breaker is used in an electrical system to carry, make & break the circuit. It consists of power contacts and control contacts. The purpose of control contacts is to connect / disconnect the accessories / equipments connected in the control circuit.
A circuit breaker has been categorised into two versions Fixed and Withdraw-able. Withdraw-able type of version consists of withdraw-able unit also known as Cradle and the Breaker part.
In Withdraw-able type of Circuit breakers, there is a connected position where the Primary as well as secondary contacts are engaged. There is a disconnected position where the Primary as well as secondary contacts are disengaged. Additionally, it is a common practice to provide a Test position between Connect and Disconnect positions of circuit breaker, where secondary contacts are engaged but primary contacts are not engaged. US 6696654 discloses unipolar design of SICs which provides flexibility to build schematic logistics by exploiting programmability of design & which is flexible for subsequent addition, deletion or replacement of SICs with minimum efforts.

US patent 5691518 discloses automatic interlocking mechanism for use in aligning a circuit device with an enclosure wherein it can be moved into and out among three distinct positions. It comprises a sliding block slidably mounted on guide bar and means for locking the slide block in place on the guide bar at a point corresponding to test position. Latching means are provided that cause slide block to latch on to the circuit device in test position.
US patent 5434369 provides guide rail mounted on enclosure & position so that it extends substantially parallel to direction of movement of circuit device into & out.
US patent 6179637 discloses an assembly for automatically mating a plug terminal attached to exterior of a circuit breaker with a receptacle terminal attached to interior of switchgear to provide secondary connections.
The assembly includes means for automatically adjusting the position of plug to provide proper alignment between plug terminal and receptacle terminal to form an electrical connection between terminals which can be disengaged.
US 6459054 discloses adjustable Circuit breaker Portion of a secondary contact assembly that may be adjusted to couple a Circuit breaker which can be retrofitted in variety of Circuit breaker enclosures.
The contact assembly is assembled by placing individual contact units on mounting rail. The contact units may be maintained in a proper spaced relation by spacers. Also suggests that, the contact units may be attached by any common method such as ultrasonic welding, glue or a friction fit.
The drawbacks of the above mentioned prior art is that circuit breakers are employed with either dovetailed or block type construction of mounting arrangement for secondary isolating contacts. In dovetailed construction, each SIC

position is interdependent i.e. position of a SIC is decided by the positioning of adjacent SIC.
Due to variation in the manufacturing parameters, this may result into flowering or anti-flowering of the Breaker SICs, causing misalignment of breaker and cradle SICs while rack-in operation. In block type construction, it becomes mandatory to provide all the SICs in a block irrespective of its use which is not cost-effective.
To enhance the reliability of mounting of SICs and to have cost-effective solution there is a need to provide an improved mounting mechanism for secondary Isolating contacts.
OBJECTS OF THE INVENTION
One object of the present invention is to overcome the disadvantages / drawbacks of the prior art.
A basic object of the present invention is to provide an improved mechanism for mounting of breaker secondary isolating contacts in mounting block of circuit breaker.
These and other advantages of the present invention will become readily apparent from the following detailed description taken 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.
According to one of the aspect of the present invention there is provided an
improved mechanism for mounting of breaker secondary isolating contacts (SIC)
in mounting block of circuit breaker, said mechanism comprising
atleast one mounting block of circuit breaker, said mounting block having
a slot in the mounting block;
a snap-fit means on said Mounting Block to provide with snap fit action ;and
a slot substantially T-shaped on said Mounting Block;
atleast one secondary isolating contacts (SIC) assembly mounted on said
mounting block of circuit breaker, said assembly having
a spring clamp;
a contact;
a housing adapted to accommodate said spring and contact within it;
a cover placed on said assembly to have cassette type construction;
an elongation on the bottom of said assembly;
an slit means provided at one end of said assembly to provide snap fit mechanism
to said snap-fit means; and
an extrude substantially T-shaped on the back side of said assembly;
wherein said elongation on Breaker SIC Housing is inserted in slot (9) in the Mounting Block such that the arrangement blocks all movement of the Breaker SIC in x-axis direction ;
wherein said slit means on Breaker SIC housing is trapped by Snap-fit action of the a snap-fit means on the Mounting Block such that the snap-fit arrangement blocks all movement of the Breaker SIC in y-axis direction ; and

wherein said T-shaped extrude is inserted in a T-shaped slot on the Mounting Block such that the arrangement blocks all movement of the Breaker SIC in z-axis direction.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an improved mechanism for mounting of the breaker secondary isolating contact (SIC) in the circuit breaker.
The Self aligning mechanism for secondary Isolating contacts which are also called as auxiliary type of contacts, calls for the independent positioning of the breaker SIC assembly in the mounting block.
The improved mounting comprises of a T shape section provided in the breaker SIC housing & a corresponding slot of T shape in mounting block which restricts the play in Z axis, a circular protrusion provided in the breaker SIC housing restricts the play in X axis & a snap provided in the mounting block hold the breaker SIC in the Y axis. Provision of mounting arrangement features in three axis, ensures positive assembly of breaker SIC in the mounting block.
In the present invention the breaker secondary isolating contact has a cassette type modular construction, which is mounted in the mounting block. It gives the advantage of having a block type robust construction & also the benefits of providing individual.
According to one of the embodiment of the present invention there is provided an improved mechanism for mounting of breaker secondary isolating contacts (SIC) in mounting block of circuit breaker. The mechanism comprising atleast one mounting block of circuit breaker and atleast one secondary isolating contacts (SIC) assembly mounted on the mounting block of circuit breaker.

The mounting block of circuit breaker comprises a slot in the mounting block , a snap-fit means on the Mounting Block to provide with snap fit action and a slot substantially T-shaped on the Mounting Block;
The secondary isolating contacts (SIC) assembly mounted on the mounting block of circuit breaker, comprises a spring clamp, a contact, a housing adapted to accommodate the spring and contact within it, a cover placed on the assembly to have cassette type construction, an elongation on the bottom of the assembly, an slit means provided at one end of the assembly to provide snap fit mechanism to the snap-fit means and an extrude substantially T-shaped on the back side of the assembly.
The elongation on Breaker SIC Housing is inserted in slot in the Mounting Block such that the arrangement blocks all movement of the Breaker SIC in x-axis direction.
The slit means on Breaker SIC housing is trapped by Snap-fit action of the a snap-fit means on the Mounting Block such that the snap-fit arrangement blocks all movement of the Breaker SIC in y-axis direction and the T-shaped extrude is inserted in a T-shaped slot on the Mounting Block such that the arrangement blocks all movement of the Breaker SIC in z-axis direction.
The advantage of this type of assembly is that a single SIC can perform the function even if other SICs are not provided (the No. of SICs which can be provided depends on the requirement of customer).
Another advantage is that, it is easy to add, remove and replace any of the contacts with minimum efforts due to the Snap-fit assembly method.
Features:
• Flexibility to mount individual contact
• Aids in self-aligning mounting block of Breaker SIC

• No interdependency of breaker secondary isolating contacts even though having the feature of individual type of contact
• Block type of construction to ensure proper aligning or guiding of contact system
• Cost effective solution to end customer
• Ease of termination with spare accessories
• Easy to add, remove and replace SICs
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawing:
Fig 1 illustrates Breaker SIC.
Fig 2 illustrates isometric views of the fully assembled Breaker SIC.
Fig 3 illustrates isometric views of the fully assembled Breaker SIC.
Fig.4 illustrates assembling of Breaker SIC on the Mounting Block.
Fig 5 illustrates assembling of Breaker SIC on the Mounting Block.
Fig 6 illustrates the fully assembled Mounting block.
Fig 7 illustrates assembling of Mounting Blocks on a Bridge.
Fig 8 illustrates Mounting Blocks being assembled on a bridge.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWING
In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and illustrate the best mode presently contemplated for carrying out the invention. Further functioning of the mechanism has been discussed below to describe the way the mechanism operates. However, such description should not be considered as any limitation of scope of the present unit. 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.
Fig 1 shows Breaker SIC Housing (1) which accommodates SIC contact (2) and spring clamp (3). Cover (4) is placed on this assembly to have the cassette type of construction. The extruded portion (5) is provided for Snap-fit assembly.
Fig 2 and fig 3 show isometric views of the fully assembled Breaker SIC with cassette type construction. The circular extrude (7) and "T"-shaped extrude (6) can be seen in Fig.2 and Fig.3 respectively. These Breaker SICs are mounted on a Mounting Block (12).
As shown in Fig.4 and Fig.5, Breaker SIC is assembled on the Mounting Block (12). The movement of SIC restricted in all the directions as follows:
i) The Circular extrude (7) on Breaker SIC Housing (1) is inserted in Circular Slot (9) in the Mounting Block (12). In the fully assembled condition shown in Fig.6, this arrangement blocks any movement of the Breaker SIC in x-axis direction shown in Fig.4 and Fig.6.
ii) The Extruded portion (5) on Breaker SIC housing (1) is trapped by Snap-fit action of the Snap (8) on the Mounting Block (12). This Snap-fit arrangement

blocks any movement of the Breaker SIC in y-axis direction shown in Fig.4 and Fig.6.
iii) The T-shaped extrude (6) is inserted in a T-shaped slot (11) on the Mounting Block (12) as shown in Fig.5. This arrangement blocks any movement of the Breaker SIC in z-axis direction.
Fig.6 shows the fully assembled Mounting block (12) with 10 Breaker SICs mounted on it. The movement of Breaker SICs is restricted in all directions. The Breaker SICs have no interdependency in the mounting block, i.e. every SIC has a separate mounting and is not dependent on the adjacent SICs for positioning.
The advantage of this type of assembly is that a single SIC can perform the function even if other SICs are not provided (the No. of SICs which can be provided depends on the requirement of customer).
Another advantage is that, it is easy to add, remove and replace any of the contacts with minimum efforts due to the Snap-fit assembly method.
These Mounting blocks are then assembled on a Bridge (13) as shown in Fig.7. Again, the mounting arrangement of block is such that a single SIC mounted on single Block can perform the function efficiently (no interdependency).

WE CLAIM
1. An improved mechanism for mounting of breaker secondary isolating contacts (SIC) in mounting block of circuit breaker, said mechanism comprising atleast one mounting block of circuit breaker, said mounting block having
a slot (9) in the mounting block ;
a snap-fit means (8) on said Mounting Block to provide with snap fit action ;and
a slot (11) substantially T-shaped on said Mounting Block;
atleast one secondary isolating contacts (SIC) assembly mounted on said mounting block of circuit breaker, said assembly having
a spring clamp(3);
a contact (2);
a housing (1) adapted to accommodate said spring and contact within it;
a cover (4)placed on said assembly to have cassette type construction;
an elongation (7) on the bottom of said assembly ;
a slit means (5) provided at one end of said assembly to provide
snap fit mechanism to said snap-fit means;
an extrude (6) substantially T-shaped on the back side of said
assembly;
wherein said elongation (7) on Breaker SIC Housing is inserted in slot (9) in the Mounting Block such that the arrangement blocks all movement of the Breaker SIC in x-axis direction ;
wherein said slit means (5) on Breaker SIC housing is trapped by Snap-fit action of the a snap-fit means (8) on the Mounting Block such that the

snap-fit arrangement blocks all movement of the Breaker SIC in y-axis direction; and
wherein said T-shaped extrude is inserted in a T-shaped slot on the Mounting Block such that the arrangement blocks all movement of the Breaker SIC in z-axis direction.
2. Mechanism as claimed in claim 1 wherein said slot on the mounting block is circular.
3. Mechanism as claimed in claim 1 wherein said elongation on the bottom of said assembly is circular.
4. Mechanism as claimed in claim 1 wherein said slit means provided at one end of said assembly is elongated to get engaged with said slit means.
5. Mechanism as claimed in claim 1 wherein said mounting blocks are assembled on a bridge (13).
6. An improved mechanism for mounting of breaker secondary isolating contacts (SIC) in mounting block of circuit breaker as herein substantially described and illustrated with the accompanying drawings.