FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION:
SHUTTER ASSEMBLY MECHNISM FOR SWITCHBOARD MODULES
APPLICANT:
LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra
INDIA.
PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A) TECHNICAL FIELD
[0001] The present invention generally relates to electrical
switchboards and particularly to safety device for electrical switchboard modules. The present invention more particularly relates to a protective shutter device for electrical switchboard modules.
B) BACKGROUND OF THE INVENTION
[0002] The use of electrical devices is well known for making, breaking
and providing safety in a typical electrical distribution system.
[0003] Control devices which are used to control the electrical current
distribution to multiple motors/loads, such as a multiple number of Motor Control Centre (MCC) modules in a central location, are generally housed in compartmented panels called Motor Control Centres (MCC) which are part of a switchboard. The MCC modules are mounted inside a board or panel board for operator safety.
[0004] The installations of electrical devices are generally of two
types. In one type of installation, electrical devices are stationary mounted to structural members or frame of the board. In such stationary installations, the inspection and the maintenance of the circuit breaker is difficult and quite hazardous when attempted while the board is live. To reduce the hazards of working with live boards, a shutter mechanism is provided to automatically prevent access to the bus bars used in such enclosures to reduce the risk of inadvertent electrical contact by a technician installing or removing an equipment from the enclosure.

[0005] The stationary exposed terminals create a safety hazard and are
very dangerous and may even cause serious injuries. An operator could be severely burned or get electrical shock, when the terminals are accidentally touched during the servicing of the electrical panel or installing other electrical components near the terminals. Therefore it is desirable to shut off the access to the exposed terminals to prevent direct contact with the energized terminals, when a control device is removed.
[0006] As a safety device, the safety shutters must not allow a direct user access to the exposed stationary terminals and must give access only, when a module is getting inserted into the panel. Hence a safety mechanism is to be designed in such a manner so that the shutter is moved away from and does not interrupt the module path towards stationary electrical connector during the insertion of a module into the panel. Also the safety shutter should return to its position instantly when the module is removed from the panel.
[0007] Conventionally there exists a band of shutter arrangements
which are mounted to the rear portion of the individual compartments in a panel. When the module is inserted into the compartment, shutters slide to different areas to expose the terminals for connection with the control device. However, the functioning of these safety shutter mechanisms is not so instant.
[0008] Hence, there exists a need to provide a safety shutter
mechanism to provide instant protection and to ensure the safety of the personnel working in the front panel when a module is in test or isolation condition during the insertion or removal of the modules from the panel.

[0009] The above mentioned shortcomings, disadvantages and
problems are addressed herein and which will be understood by reading and studying the following specification.
C) OBJECT OF THE INVENTION
[0010] The primary object of the present invention is to provide an
improved safety shutter assembly mechanism for compact modules of switchboards.
[0011] Another object of the present invention is to provide a safety
shutter assembly mechanism to provide safety to an operating personnel instantly during the insertion and removal of the modules in switchboards.
[0012] Yet another object of the present invention is to provide a safety
shutter assembly mechanism to ensure the safety of a person working in front panel when it is in test and isolation condition.
[0013] These and other objects and advantages of the present invention
will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION
[0014] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.

[0015] According to the embodiments of the present invention, a shutter assembly mechanism for switchboards having at least one module comprises a housing mechanism attached with the at least one module and a cam is provided in the housing mechanism. A connecting pin is attached to the cam and a lever is coupled to the connecting pin. A top shutter is connected to one end of the lever and a bottom shutter is connected to another end of the lever. The shutter housing encloses the top shutter and the bottom shutter,
[0016] The horizontal movement of the module is converted to rotational movement of the cam so that safety shutter is opened and closed. The rotational movement of the cam opens the top shutter and the bottom shutter during a rack-in of the module and closes the top shutter and the bottom shutter during a rack-out of the module to provide a safety to the operating personnel working in the front panel. When the module is racked-in, it pushes the cam in a horizontal direction. Since the cam is assembled in a stationary housing, the cam moves in a forward (horizontal) direction. A lengthwise slot is provided inside the cam. When the cam moves in a forward direction, the connecting pin is rotated due to the shape of the cam. The slot in the cam is adjusted in such a way that the connecting pin rotates at an angle of 180 degrees.
[0017] The internal shape of the cam is arranged sothat the cam converts radial movement into rotational movement through the connecting pin. When the connecting pin is rotated, it pushes the bottom shutter towards bottom side since the bottom shutter is connected with one limb of connecting pin. Another limb of connecting pin is connected to the lever. Hence the lever is moved in an upward direction to push the top shutter towards the upper side. The safety shutter housing guides the movement of top and bottom. shutter in the vertical directions. Thus it opens the shutter and the moving female contacts get engaged with stationary male contacts.

[0018] When a module is racked-out, it pushes the cam in a backward direction with respect to the normal position. The movement of the cam causes the connecting pin to rotate in an anti-clockwise direction because of the shape of the cam. When the connecting pin rotates in anti-clockwise direction by 180 degrees, it pushes the bottom shutter and the top shutter to the original position. Thus it closes the shutter and the moving female contacts get disengaged from the stationary male contacts.
[0019] The individuals working in front of the panel board are not exposed to the live contacts even when the module is in isolation position, since the safety shutter becomes the barrier between the live contacts and functional unit. This provides for the safety of the individuals who are working in front of the panel board,
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The other objects, features and advantages will occur to those
skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0021] FIG.l illustrates the safety shutter assembly mechanism,
according to one embodiment of the present invention.
[0022] FIG.2 illustrates a housing mechanism of the safety shutter
assembly mechanism, according to one embodiment of the present invention.
[0023] FIG.3 illustrates a connecting pin of the safety shutter assembly
mechanism, according to one embodiment of the present invention.

(0024] FIG.4 illustrates a cam in the housing mechanism of the safety shutter housing assembly mechanism, according to one embodiment of the present invention.
[0025] FIG.5 illustrates a lever of the safety shutter assembly mechanism, according to one embodiment of the present invention.
[0026] FIG.6 illustrates a safety shutter housing of the safety shutter assembly mechanism, according to one embodiment of the present invention.
[0027] FIG.7 illustrates a bottom shutter of the safety shutter assembly mechanism, according to one embodiment of the present invention.
[0028] FIG.8 illustrates a top shutter of the safety shutter assembly
mechanism, according to one embodiment of the present invention.
[0029] FIG.9 illustrates the safety shutter assembly mechanism, according to one embodiment of the present invention.
[0030] Although specific features of the present invention are shown in
some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0031] In the following detailed description, reference is made to the
accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These

embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0032] The various embodiments of the present invention provide a
safety shutter assembly mechanism for switchboards. The movable part of a contact is mounted on a module of the switchboard which is the male part and the stationary part of a contact is mounted on a structure which is the female part. When a module is pushed inside the structure, female contacts get engaged with male contacts and the module gets the power supply. This position is called as service position. But when module is pulled out, both the contacts gets disengaged with each other. In this position, the stationary part of the contact is live and at this condition it is not accessible. To avoid the access of stationary live conductor, safety shutter is used. This safety shutter provides a path to engage the female contacts with the male contacts when module is in service condition. When both the contacts are disengaged, the shutter assembly mechanism avoids the access of the live stationary conductor for human or any other module part.
[0033] FIG.l illustrates the safety shutter assembly mechanism,
according to one embodiment of the present invention. The safety shutter assembly includes a housing mechanism 1 assembled with a functional unit such as a stationary part of the module. The housing mechanism 1 includes a connecting cam 3 and a lever 4 coupled to it. The cam 3 comprises a connecting pin 2.The lever 4 is assembled with the connecting pin using a connecting means such as a metallic pin to transfer the motion to the safety shutter assembly mechanism.

[0034] The safety shutter assembly mechanism further comprises a top safety shutter 7 and a bottom safety shutter 6. The top safety shutter 7 and the bottom safety shutter 6 are enclosed within a shutter housing. The connecting pin 2 herein includes two limbs. One limb 22 is connected with the lower part 62 of lever and the other limb 21 is connected with bottom safety shutter 6. The upper part 61 of the lever is connected with the top safety shutter 7. The safety shutters 6 and 7 are assembled to the lever 4 and connecting pin 2 using rivets 8, for instance, plastic rivets.
[0035] The cam 3 is designed in such a way that it converts the radial
movement of the cam into a rotational movement. When the module is racked in, it pushes the cam 3. This in turn causes a rotation of the connecting pin 2 by 180 degree. The rotation of the connecting pin 2 exerts a force on the down side of the bottom safety shutter 6 and a force on the upper side of the lever 4. The lever 4 in turn exerts a force which pushes of the top safety shutter 6 in the upper side to provide an opening of the safety shutter.
[0036] Similarly, the racking out of the module from the switch board pushes the cam 3 in an opposite direction as compared to the normal position. This in turn causes a rotation of the connecting pin 2 by 180 degrees in an anticlockwise direction. The rotation of the connecting pin 2 in an anticlockwise direction exerts a force on the top side of the bottom safety shutter 6 and a force on the bottom side of the lever 4. The lever 4 in turns exerts a force which pushes the bottom side of the top safety shutter 6, to enable a shutting operation of the safety shutter.
[0037] FIG. 2 illustrates a housing mechanism of the safety shutter
assembly mechanism, according to one embodiment of the present invention. The housing mechanism 1 is mounted on the tray 9 which is the stationary

part. The housing mechanism 1 has cam 3 inside it which is the moving part 41. The housing mechanism 1 provides the space for the rotation of the cam 3. When the module pushes the cam 3, the cam moves forward in a horizontal direction and when the module is taken out, it releases the cam 3 in a backward direction. The housing mechanism 1 also includes a lever 4 attached to it using a connecting means.
[0038] FIG.3 illustrates the connecting pin of the safety shutter
assembly. The connecting pin 2 includes two limbs. One limb 32 is adapted to be connected with the lever 4 and other limb 31 is connected with the bottom side safety shutter 6. The movement of the connecting pin 2 in a clockwise direction during the rack in of the module pushes the bottom side safety shutter 6 in a downward direction from the normal position.
[0039] FIG.4 illustrates the cam of the safety shutter assembly. The cam 3 comprises a connecting pin 2. The connecting pin 2 is assembled in the cam 3 with the help of a metal pin. The cam 3 includes a slot which extends along the length of the cam 3 through the interior of the cam 3. The shape of the slot inside the cam 3 is given in such a way that when the cam 3 moves in a forward direction, the connecting pin 2 rotates in a clockwise direction. Similarly, when the cam 3 moves in backward direction, the connecting pin 2 rotates in an anti-clockwise direction.
[0040] FJG.5 illustrates the lever of the safety shutter assembly. The
lever 4 as shown in the FIG.5 includes one hole on each end section. The hole on a first end section of the lever is adapted to receive the limb of the connecting pin 2. The hole on a second end section of the lever is adapted to engage with the top safety shutter 7. The rotation of the connecting pin 2 in a clockwise direction turns the lever 4 which is connected to connected pin 2. When the lever 4 rotates, it pushes the top side safety shutter 7 in an upward direction as compared to the standard position.

[0041] FIG.6 illustrates the safety shutter housing of the safety shutter
assembly. The safety shutter housing 5 is arranged on a structure panel on which the top safety shutter 7 and the bottom safety shutter 6 are mounted. The safety shutter housing 5 guides the movement of the top safety shutter 7 and the bottom safety shutter 6 in a vertical direction in response to the movement of the module. The person is not exposed to a live contact even when the module is in isolation position, since the safety shutter 5 becomes the barrier between a live contact and the module.
[0042] FIG.7 illustrates the bottom side shutter of the safety shutter
assembly. The connecting pin 2 includes two limbs. One limb 32 is connected with the lever 4 and the other limb 31 is connected with the bottom safety shutter 6. When the connecting pin 2 rotates in a clockwise direction, it pushes the bottom safety shutter 6 in a downward direction. This inturn opens the bottom side shutter 6 of the safety shutter assembly. Similarly when connecting pin 2 moves in an anti-clockwise direction, it pulls back the bottom shutter 6 to the original position.
[0043] FIG.8 illustrates the top side shutter of the safety shutter
assembly. The limb 32 of the connecting pin 2 is connected with the opening on one end section 62 of the lever 4 and the opening on other end section 61 of the lever 4 is connected with the top safety shutter 7. When the connecting pin 2 rotates in a clockwise direction, it in turns rotates the lever 4 which is connected to the connected pin 2. When the lever 4 is rotated, it pushes the top side safety shutter 7 in an upward direction. Similarly when a connecting pin 2 is rotated in anti-clockwise direction, it inturn rotates the lever 4 which is connected to the connecting pin 2. When the lever 4 is rotated, it pulls back the top safety shutter 7 to the original position.

[0044] FIG.9 illustrates the rivets of the safety shutter assembly. The
safety shutters 6, 7 are assembled to the lever 4 and the connecting pin 2 using a plurality of rivets 8. The safety shutter housing 5 is mounted on the panel structure. This guides the movement of top 7 and bottom safety shutter 6 in vertical direction. The rivet 8 is made of of plastic or metal or any other suitable material,
G) ADVANTAGES OF THE INVENTION
[0045] Thus the various embodiments of the present invention provide a protective safety shutter assembly mechanism for switchboards.
[0046] The safety shutter assembly of the present invention functions as a barrier between the live contacts and the functional units such as modules assuring the safety of a person who is working in front of the panel.
[0047] The safety shutter system of the present invention is very
compact and converts the horizontal movement of the module into vertical movement of the shutter thereby opening and closing the shutter according the position of the module.
[0048] The safety shutter assembly of the present invention is compact
enough to be used in compact modules, for instance modules with a height of 140 mm and the like.
[0049] Although the invention is described with various specific
embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

[0050] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.

CLAIMS
What is claimed is:
1. A shutter assembly mechanism for switchboards having at least one module, the
mechanism comprising:
a housing mechanism attached with the at least one module;
a cam provided in the housing mechanism;
a connecting pin attached to the cam;
a lever coupled to the connecting pin;
a top shutter connected to at least one end section of the lever;
a bottom shutter connected to at least one end section of the lever; and
a shutter housing enclosing the top shutter and the bottom shutter;
where in a rotational movement of the cam causes the top shutter and the bottom shutter to open during a rack-in of the module and causes the top shutter and the bottom shutter to close during a rack-out of the module to provide a safety shutting operation.
2. The shutter assembly mechanism according to claim 1, wherein the top shutter
and the bottom shutter are connected with the lever through a rivet.
3. The shutter assembly mechanism according to claim 1, wherein at least one rivet is formed of plastic.
4. The shutter assembly mechanism according to claim 1, wherein one end of the connecting pin is attached to the lever and other end of the connecting pin is attached to the bottom shutter.

5. The shutter assembly mechanism according to claim 1, wherein the cam is shaped to convert a radial movement to the rotational movement.

6. The shutter assembly mechanism according to claim 1, wherein the rotational movement of the cam causes a rotation of the connecting pin.

7. The shutter assembly mechanism according to claim 1, wherein the rotation of the connecting pin induce a force on one side of the bottom shutter.

8. The shutter assembly mechanism according to claim 1, wherein the rotation of the connecting pin induce a force on one side of the lever.

9. The shutter assembly mechanism according to claim 1, wherein the lever transfers the force induced on the lever to the top shutter thereby pushing away the top shutter from the bottom shutter during rack-in of the module.

10. The shutter assembly mechanism according to claim 1, wherein the lever transfers the force induced on the lever to the top shutter thereby drawing the top shutter towards the bottom shutter during rack-out of the module.