FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and ruie 13)
1. TITLE OF THE INVENTION:
"Assembly for Converting Fixed Type Moulded Case Circuit Breaker into Plug
in/Plug out Type"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: LARSEN & TOUBRO LIMITED,
L&T House, Ballard Estate, P. 0. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Assembly for Converting Fixed Type Moulded Case Circuit Breaker into Plug
in/Plug out Type
Field of the invention
The present invention relates generally to circuit breakers, and more particularly, to an assembly for converting fixed type moulded case circuit breaker into plug in/plug out type.
Background of the invention
Moulded case circuit breaker (MCCB) is electrical equipment used for protecting the electrical circuits and loads by automatically breaking the electrical circuit when fault, such as short circuit, over/earth fault current occurs.
Existing MCCB do not have any external attachment which will be used as a package when the MCCB needs to be converted in to plug-in type or to be sold as a plug-in type MCCB. The MCCB comprises of terminal parts which connects to a power source or an electrical load of the circuit, a switching mechanism which switches (ON/OFF) the circuit by contacting a fixed contact with a movable contact inside the MCCB, and a trip mechanism which helps to sense the fault and helps the switching mechanism to break the circuit. Such type of MCCB is called as a fixed type MCCB. as it is assembled in an enclosure called as switchboard.
The MCCB terminals are connected to the main power source through copper links called bus bars. There may be one MCCB or can be combination of more than one MCCB depending upon the load and numbers of equipments in circuit. However, at the time of maintenance or when fault occurs in the MCCB, service engineers or person attending the situation has to shut down complete system, which affects the operation of other auxiliary equipment depending on the system.

Accordingly, there exists a need to provide an assembly which does not require shutting down the entire system for maintenance of the MCCB and which overcomes above mentioned drawbacks.
Objects of the invention
An object of the present invention is to convert fixed type moulded case circuit breaker (MCCB) into plug-in /plug-out type MCCB without affecting current nomenclature of the MCCB.
Yet another object of the present invention is to provide visual guiding system which eases plug-in process of the MCCB in a switch board.
Summary of the invention
Accordingly, the present invention provides an assembly for converting fixed type moulded case circuit breaker (MCCB) into plug in/plug out type. The assembly includes a plurality of contact spacers arranged in slots provided for MS nut plate in housing of the MCCB, a plurality of bushes arranged at rear side of the housing in communication with the plurality of contact spacers and a guiding unit. The guiding unit includes a back plate capable of being secured to the rear side of the MCCB housing, and a bracket affixed to the back plate forming an enclosure for the housing. When the housing is secured to the back plate, the plurality of bushes passes through the back plate and protrudes from rear side thereof. Further, the guiding unit includes a plurality of male contacts assembled at rear side of the back plate in communication with the plurality of bushes, wherein the plurality of male contacts communicates with plurality of female contacts of a switchboard panel. Furthermore, the guiding unit includes a plurality of rear phase barriers configured between the plurality of male contacts, a plurality of front phase barriers configured in between slots of the housing, and a first terminal cover positioned at the top of the housing and a second terminal cover positioned at the bottom of housing. The first terminal cover and the second terminal cover are juxtaposed to the back plate. Wherein upon assembling the MCCB in

the guiding unit, the MCCB is capable of being plug out with manual force and after rectification/replacement the MCCB is capable of being plug-in to the switchboard panel.
Brief description of the drawings
Figure 1 shows an exploded view of an assembly for converting a fixed type moulded case circuit breaker (MCCB) to plug in/plug out type;
Figure 2a and 2b shows arrangement of a plurality of bushes and contact spacer in slots provided for a MS nut plate:
Figure 3a and 3b shows a back plate of the assembly of figure 1.
Figure 4 shows an attachment of a bracket on the back plate of the assembly of figure 1:
Figure 5a and Figure 5b shows attachment of the MCCB with the back plate of the assembly of figure 1;
Figure 6 shows attachment of rear male contacts on the back plate of the assembly of figure 1;
Figure 7 shows attachment of rear phase barrier on the back plate of the assembly of figure 1;
Figure 8 shows a front terminal cover of the assembly of figure 1;
Figure 9a and 9b shows a front phase barrier of the assembly of figure 1;
Figure 10 shows handles of the assembly of figure 1:

Figure 11a and l1b shows sliding of the MCCB in the switchboard assembly of figure 1; and
Figure 12 shows a front view of the MCCB in the assembly of figure 1.
Detailed description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
The present invention provides an assembly for converting fixed type moulded case circuit breaker into plug in/plug out type. The MCCB engagement in the assembly is assured by interlocked slots provided on a back plate. The guiding arrangement for the MCCB is visible from front side while inserting the MCCB in fixed part, for e.g. a guiding unit, which helps the operator to align the MCCB easily.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.
Referring to figure 1 to 12. there are shown various views and components of an assembly converting fixed type moulded case circuit breaker into plug in/plug out type. Specifically, figure I shows an exploded view of the assembly (100) for converting fixed type moulded case circuit breaker into plug in/plug out type (hereinafter 'the assembly (100)'). The assembly (100) includes a plurality of contact spacers (10), a plurality of bushes, for example, the plurality of copper bushes (20b), a plurality of nylon bushes (20a) and a guiding unit (50).
The plurality of contact spacers (10) are arranged in slots (not numbered) provided for MS nut plate in a housing (15) of the moulded case circuit breaker (25) (hereinafter the "MCCB (25)') as shown in figure 2a and 2b. Further, the plurality of copper bushes

(20b) and the plurality of nylon bushes (20a) are arranged at rear side of the housing (15). The plurality of copper bushes (20b) and the plurality of nylon bushes (20a) lie in communication with the plurality of contact spacers (10).
The guiding unit (50) includes a back plate (30), a bracket (32), a plurality'' of male contacts (34), a plurality of rear phase barriers (36), a plurality of front phase barriers (38), a first terminal cover (40) and a second terminal cover (42).
The back plate (30) is capable of being secured to the rear side of the housing (15). As shown in figure 3a and 3b. the back plate (30) includes opening (30a) configured thereon along with nuts (30b) for fixing to the switchboard panel. In an embodiment, the back plate (30) is non-metallic. The bracket (32) is affixed to a front side of the back plate (30).
Specifically, the bracket (32) as shown in figure 4, includes two outwardly extending side plates (32a, 32b). The bracket (32) when attached to the back plate (30) forms an enclosure for the housing (15) of the MCCB (25). In an embodiment, the bracket (32) is a metallic bracket. When the housing (15) is secured to the back plate (30), the plurality of copper bushes (20b) passes through the back plate (30) and protrude from rear side thereof as shown in figure 5a and 5b. The back plate (32) includes the plurality of male contacts (34) assembled at rear side thereof.
Further, the side plates (32a, 32b) are connected to each other by means of a first rod (32c) at the top portion and a second rod (32d) at the bottom portion thereof. The first rod (32c) and the second rod (32d) provides for easy handling of the enclosure formed by the bracket (32) and the back plate (30), resulting in easy plug-in and plug-out of MCCB (25).
Specifically, the plurality of male contacts (34) are assembled at the rear side of the back plate (32) in communication with the plurality of copper bushes (20b) and the plurality of nylon bushes (20a) as shown in figure 6. The plurality of male contacts (34) are capable of communicating with plurality of female contacts (60) of the switchboard

panel (not numbered). The plurality of male contacts (34) are separated from each other by means of the plurality of rear phase barriers (36).
Specifically, the plurality of rear phase barriers (36) are configured between the plurality of male contacts (34), and the plurality of front phase barriers (38) are configured in between front slots (not shown) of the housing (15) as shown in figure 7 and 9a, 9b respectively.
Further, the first terminal cover (40) is positioned at the top of the housing (15) and the second terminal cover (42) is positioned at the bottom of housing (15) as shown in figure 8. Specifically, the first terminal cover (40) and the second terminal cover (42) juxtaposed to the back plate (30) thus providing shrouding to the housing (15).
When the MCCB (25) along with the guiding unit (50) is assembled in the switchboard panel, the MCCB can be plugged out with manual force and after rectification or repair; the MCCB (25) can be plugged-in to the switchboard panel.
Specifically, with the help of external attachments such as guiding unit (50) and without compromising the nomenclature of current MCCB, the existing MCCB can be converted in to plug-in type as described above. Accordingly, without disconnecting/ shutting down the main power line, the MCCB (25) can be plugged out with manual force and plugged in to the electrical circuit.
More specifically, this guiding arrangement of the MCCB (25) along with the guiding unit (50) in the switchboard panel is visible from front side while inserting the MCCB (25) in the switchboard panel. This helps an operator to align the MCCB easily in the switchboard panel as shown in figure 11a, l1b and 12.
The MCCB engagement in the assembly (100) is assured by interlocked slots (70) provided on a back plate.

The present invention provides guiding before establishing electrical contacts happens in between the MCCB (25) and in the switchboard panel. This feature ascertains an exact alignment of electrical contacts of MCCB (25) within the switchboard panel. Further, the guiding the MCCB (25) in the switchboard panel before establishing the electrical contacts ensures that there is not any mechanical loads of MCCB on electrical contact.
In an embodiment, the assembly (100 is used for marine application which are generally susceptible to shock and vibration during their normal operation. To take care of this stringent design specification, fixing screws are provided at four corners of the assembly (100) to fix the MCCB (25) after insertion thereof in the switchboard panel. These fixing of the assembly (100) is done on the structure of the switchboard panel and not on the fixed part i.e. the guiding unit (50), which provides good mechanical rigidity to the assembly.
Advantages of the invention
1. The assembly (100) converts fixed type MCCB into plug-in/plug-out type MCCB.
2. The visual guiding system in the plug-in /plug-out MCCB of the present invention is eases plug-in process.
3. The assembly (100) includes rods which provide unique handle arrangement for ease of handling.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various

modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We claim
1. An assembly for converting fixed type moulded case circuit breaker
(MCCB) into plug in/plug out type, the assembly comprising:
a plurality of contact spacers arranged in slots provided for MS nut plate in a housing of the MCCB;
a plurality of bushes arranged at rear side of the housing in communication with the plurality of contact spacers; and a guiding unit having,
a back plate capable of being secured to the rear side of the housing,
a bracket affixed to the back plate forming an enclosure for the housing, wherein when the housing is secured to the back plate, the plurality of bushes pass through the back plate and protrude from rear side thereof.
a plurality of male contacts assembled at rear side of the back plate in communication with the plurality of bushes, the plurality of male contacts being capable of communicating with plurality of female contacts of a switchboard panel.
a plurality of rear phase barriers configured between the plurality of male contacts,
a plurality of front phase barriers configured in between slots of the housing, and
a first terminal cover positioned at the top of the housing and a second terminal cover positioned at the bottom of housing, the first terminal cover and the second terminal cover juxtaposed to the back plate,
wherein upon assembling the MCCB in the guiding unit, the MCCB is capable of being plugged out with manual force and after rectification/replacement the MCCB is capable of being plugged in to the switchboard panel.
2. The assembly as claimed in claim 1, wherein the bracket includes two
outwardly extending side plates connected by rods.

3. The assembly as claimed in claim I, wherein the plurality of bushes includes a plurality of copper bushes and a plurality of nylon bushes.