FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section ] 0 and rule ] 3)
TITLE OF THE INVENTION:
SAFETY SHUTTER ASSEMBLY FOR MODULES OF
SWITCHBOARD
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 modules of electrical switchboard. The present invention more particularly relates to a protective shutter device for modules of electrical switchboard with a pad lock lever assembly.
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. 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 Centers (MCC) which are part of a switchboard. The MCC modules are mounted inside a board or panel board for operator safety.
[0003] Safety shutter is a mechanism which isolate live conductor like
droppers from functional unit like module when it is not in service position. The functional unit has three different positions such as service position, test position and isolation position. In service condition, the moving contacts are engaged with stationary conductor whereas in both test condition and isolation condition both the moving contacts and stationary conductors are disengaged. When module is in service condition and test condition, the module should be isolated from live conductor.
[0004] When module is in test condition or isolated condition, the
safety shutter is in closed condition. When module is rack in the panel, the safety shutter starts opening. The safety shutter opens completely when the

module comes to service condition and the moving contacts are engaged with stationary current carrying conductor. The movement of safety shutter depends upon the movement of module.
|0005] When module is racking out, the safety shutter starts closing
with respect to the module movement. The safety shutter is completely closed down when the moving contact is completely disengaged from the stationary conductor. This assures safety of person who is working in front of panel. The operating person cannot see live contact even if module is in isolation position since safety shutter becomes the barrier between live contact and functional unit. Vice versa the safety shutter allows the engaging of contacts when the module is rack in.
[0006] However, when module is removed for maintenance purpose,
the safety shutter remains in closed condition and the live conductor such as the dropper contacts are not exposed. In this condition, the safety shutter is pushed in manually which lead to expose the live conductor, which is unsafe.
|0007] Hence, there exists a need to provide a locking mechanism for
switchboards which allows locking of safety shutter when module is not there in feeder compartment. There also exists a need to provide a locking mechanism which prevents contact of operating personal with the live conductor.
[0008] 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

[0009] The primary object of the present invention is to provide an
improved locking mechanism for safety shutter mechanism for switchboards.
[00101 Another object of the present invention is to provide a safety
shutter mechanism for compact modules of switchboards.
[0011] Yet another object of the present invention is to provide a safety
shutter assembly mechanism which functions in response to the movement of the module.
[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 the module is in test condition 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] The various embodiments of the present invention provide a
pad lock for safety shutter mechanism in switchboards. The mechanism comprising of mainly two parts a safety shutter mechanism mounted above the tray (also called as housing mechanism of safety shutter) and pad locking lever mechanism mounted below the tray.

[0016] A padlock lever comprising at least one limb placed in a center
leads in to the housing mechanism of safety shutter and locks the movement. At the end of this pad lock Jever an extrusion is provided for locking the safety shutter and a projection is provided at the other end of the pad lock lever for fixing the pad lock lever to the tray.
[0017] According to one embodiment, the one end of the pad lock
lever is attached to the tray with a small bolt.
[0018] According to one embodiment, the extrusion at one end of the
pad lock lever is larger than a cut out provided on the tray.
[0019] According to one embodiment, wherein the pad lock lever is
lifted to pass the limb of pad lock lever in to a housing mechanism of the safety shutter during closed condition.
[0020] According to one embodiment, an opening is provided on the
extrusion at one end of the pad lock lever to lock the pad lock lever with a lock. The pad lock lever is made of metal
[0021] According to one embodiment, the safety shutter mechanism
includes at least one module attached with the housing mechanism, 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 a( least one end of the lever, a bottom shutter connected to at least one end of the lever; and a shutter housing enclosing the top shutter and the bottom shutter. A rotational movement of the cam causes the top shutter and the bottom shutter to open during a rack-in position of the module and causes the top shutter and the bottom shutter to close during a rack-out position of the module to provide a safety shutting operation.

[0022] According to one embodiment, at least one rivet is adopted to
connect the top shutter and the bottom shutter with the lever.
[0023] According to one embodiment, at least one end of the
connecting pin is attached to the lever and at least one end of the connecting pin is attached to the bottom shutter.
[0024] According to one embodiment, the cam is shaped to convert a
radial movement to the rotational movement and the rotational movement of the cam causes a rotation of the connecting pin. The rotation of the connecting pin induces a force on one side of the bottom shutter. The rotation of the connecting pin induces a force on one side of the lever. The [ever transfers the force induced on the lever to the top shutter thereby pushing away the top shutter from the bottom shutter during the rack-in position of the module. The lever transfers the force induced on the lever to the top shutter thereby drawing the top shutter towards the bottom shutter during the rack-out position of the module. So this avoids the movement of safety shutter, thus locking the module.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0025] 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:
[0026] FIG.l is a perspective view of a safety shutter assembly
mechanism, according to one embodiment of the present invention.
[0027] FIG.2 is a perspective view of a pad lock lever of the safety
shutter assembly mechanism, according to one embodiment of the present invention.

[0028] FIG.3 illustrates a pad lock lever assembled with tray of the
safety shutter housing assembly mechanism, according to one embodiment of the present invention.
[0029] FIG.4 is a perspective view of a lever and safety shutter
assembly of the safety shutter assembly mechanism, according to one embodiment of the present invention.
[0030] FIG.5 is a perspective view illustrating a provision for lever
assembly below safety shutter assembly, according to one embodiment of the present invention.
[0031] FIG.6 illustrates a housing of the safety shutter assembly
mechanism, according to one embodiment of the present invention.
[0032] FIG.7 illustrates a side view of pad locking of the safety shutter
assembly mechanism, according to one embodiment of the present invention.
[0033] FIG.8 is a perspective view of the padlocking mechanism of
safety shutter assembly mechanism, according to one embodiment of the present invention.
[0034] 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
[0035] 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.
[0036] The various embodiments of the present invention provide a
pad lock for safety shutter mechanism in switchboards. The mechanism comprising of mainly two parts a safety shutter mechanism mounted above the tray (also called as housing mechanism of safety shutter) and pad locking lever mechanism mounted below the tray.
[0037] A padlock lever comprising at least one limb placed in a center
leads in to the housing mechanism of safety shutter and locks the movement. At the end of this pad lock lever an extrusion is provided for locking the safety shutter and a projection is provided at the other end of the pad lock lever for fixing the pad lock lever to the tray.
J0038J According to one embodiment, the one end of the pad lock
lever is attached to the tray with a small bolt.
[0039J According to one embodiment, the extrusion at one end of the
pad lock lever is larger than a cut out provided on the tray.
[0040] According to one embodiment, wherein the pad lock lever is
lifted to pass the limb of pad lock lever in to a housing mechanism of the safety shutter during closed condition,
[0041] According to one embodiment, an opening is provided on the
extrusion at one end of the pad lock lever to lock the pad lock lever with a lock. The pad lock lever is made of metal

[0042] According to one embodiment, the safety shutter mechanism
includes at least one module attached with the housing mechanism, a cam provided in the housing mechanism, a connecting pin attached to the cam. a fever coupled to the connecting pin, a top shutter connected to at least one end of the lever, a bottom shutter connected to at least one end of the lever; and a shutter housing enclosing the top shutter and the bottom shutter. A rotational movement of the cam causes the top shutter and the bottom shutter to open during a rack-in position of the module and causes the top shutter and the bottom shutter to close during a rack-out position of the module to provide a safety shutting operation.
[0043] According to one embodiment, at least one rivet is adopted to
connect the top shutter and the bottom shutter with the lever.
(0044] According to one embodiment, at least one end of the
connecting pin is attached to the lever and at least one end of the connecting pin is attached to the bottom shutter.
[0045] According to one embodiment, the cam is shaped to convert a
radial movement to the rotational movement and the rotational movement of the cam causes a rotation of the connecting pin. The rotation of the connecting pin induces a force on one side of the bottom shutter. The rotation of the connecting pin induces a force on one side of the lever. The lever transfers the force induced on the lever to the top shutter thereby pushing away the top shutter from the bottom shutter during the rack-in position of the module. The lever transfers the force induced on the lever to the top shutter thereby drawing the top shutter towards the bottom shutter during the rack-out position of the module. So this avoids the movement of safety shutter, thus locking the module.

[0046] FIG.l is a perspective view of a safety shutter assembly
mechanism, according to one embodiment of the present invention. The assembly includes a housing mechanism 11 mounted on a tray 19 wherein the tray 19 is a stationary part of the module. The housing mechanism 11 is assembled with a functional unit comprising a connecting lever 13. The connecting lever 13 comprises one or more connecting pins 12. The connecting pin 12 has two limbs, one limb of the connecting pin 12 is connected with the lower part of the connecting lever 13 and the other limb of the connecting pin 12 is connected with the bottom safety shutter 16. The upper part of the connecting lever 13 is connected to the top safety shutter 17. The safety shutters 16 and 17 are assembled to the connecting lever 13 and the connecting pin 12 using plastic rivets 18. The assembly mainly comprising of two parts a safety shutter mechanism 15 mounted above the tray 19 and pad locking lever 21 mechanism mounted below the tray 19 ( as shown in FIG. 3). The housing mechanism II further includes, a cam 14 which is a moving part inside the housing mechanism 11. When the module pushes the cam 14, the cam 13 moves forward in horizontal direction with respect to the tray 19 and when module is taken out it releases the cam 13 in the backward direction.
[0047] FIG.2 illustrates a pad lock lever of the safety shutter assembly
mechanism, according to one embodiment of the present invention. A pad
lock 21 is a mechanism by which safety shutter 15 used in feeders is locked
when module is not in the feeder. This is positive locking by which
movement of safety shutter 15 is positively locked and avoids manual
movement of safety shutter 15. A padlock lever 21 as shown in FIG. 2a
comprising at least one limb 22 placed in center leads in to the housing
mechanism 11 of safety shutter 15 and locks the movement. At one end
of the pad lock lever 21 an extrusion 23 is provided for locking the safety shutter 15 and a projection 24 is provided at the other end of the pad lock lever 21 for fixing the pad lock lever 21 to the tray 19. The pad lock lever 21

is fixed to the tray 19 with the help of small boJt 25 as shown in FIG. 2b and FIG. 3. The pad lock lever 21 is made of metal.
[0048] FIG. 3 illustrates the pad lock Sever assembled with the tray of
the safety shutter housing assembly mechanism, according to one embodiment of the present invention. The pad lock lever 21 is fixed with the tray 19 by small M6 bolt 25. At one end of the pad lock lever 21 an extrusion 23 is provided which is larger than the cut out provided on the tray 19. This ensures that pad lock lever 21 will lock the safety shutter 15 movement during the closed condition.
[0049] FIG. 4 illustrates a lever and safety shutter assembly of the
safety shutter assembly mechanism, according to one embodiment of the present invention. When safety shutter 15 is in closed condition pad lock lever 21 is lifted because of which limb of pad lock lever 22 goes in to the housing mechanism 11 of safety shutter 15 and lock the safety shutter 15 movement. This assures safety of person who is working in front of panel. The person will never see live contact even if module is in isolation position since safety shutter becomes the barrier between live contact and functional unit.
[0050] FIG. 5 illustrates the provision for lever below safety shutter
assembly, according to one embodiment of the present invention. When safety shutter 15 is in open condition the pad lock lever 21 is not lifted because of which limb of the pad lock lever 22 does not go into the housing mechanism 11 of safety shutter 15. This allows for engaging contacts when the module is rack in.
[0051] FIG. 6 illustrates a housing mechanism for the safety shutter
assembly mechanism, according to one embodiment of the present invention. One limb is provided in the middle 22 of the pad lock lever 21 which goes in

to the housing mechanism 11 of safety shutter 15 and locks the movement of the safety shutter 15. The housing mechanism ] 1 is mounted on the tray 19. The tray 19 is the stationary part. The housing mechanism 11 includes cam 14 inside the housing mechanism 11 and the cam 14 is a moving part. When the module pushes the cam 14. the cam 14 moves forward in horizontal direction with respect to the tray 19 and when module is taken out it releases the cam 14 in the backward direction. A special arrangement is provided to the cam 14 inside the housing mechanism II, to convert horizontal movement of the cam 14 to a rotational movement. This rotational movement leads to the opening and closing of the safety shutter mechanism 15.
[0052] FIG. 7 illustrates a side view of pad locking of the safety
shutter assembly mechanism, according to one embodiment of the present invention. The pad lock lever 21 gets assembled in a particular sequence below the tray 19 and is fixed with the tray 19 by an M6 bolt 25. At one end of the pad lock lever 21 an extrusion 23 is provided for locking the safety shutter 15 and a projection 24 is provided at the other end of the pad lock lever 21 for fixing the pad lock lever 21 to the tray 19 as shown in FIG. 7. When safety shutter 15 is in closed condition pad lock lever 21 is lifted because of which limb of pad lock lever 22 goes in housing mechanism 11. So the pad lock lever 21 avoids the movement of the safety shutter 15. Then a lock 71 is inserted into the hole provided on the protrusion at one end 23 of the pad lock lever 21 and the pad lock lever 21 is locked with the lock 71. This positive locking avoids unintentional movement of the safety shutter 15 when module is not there above the tray 19.
[0053] FIG. 8 illustrates the final assembly of pad locking mechanism
of safety shutter assembly mechanism, according to one embodiment of the present invention. When safety shutter 15 is in closed condition, pad lock lever 21 is lifted because of which limb of pad lock lever 22 goes in to the

housing mechanism 11 of the safety shutter 15. So this avoids the movement of safety shutter further and the pad lock lever is locked with the help of the lock 71 as shown in FIG. 8.
[0054] Pad lock 21 is a mechanism by which safety shutter 15 which is
used in feeders can be locked when module is not in the feeder. This is positive locking by which movement of safety shutter 15 is positively locked and avoids manual movement of safety shutter 15. Safety shutter 15 is a mechanism which isolate live conductor like droppers from functional unit like module when it is not in service position.
[00551 When module is in test or isolation, safety shutter 15 is in
closed condition. When module is rack in the safety shutter 15 slowly starts opening. It opens completely when module comes to service condition and moving contacts engaged with stationary current carrying conductor. The movement of safety shutter 15 depends upon the movement of module.
[0056] When module is racking out the safety shutter starts closing
with respect to module movement. It completely closes down when the
moving contact completely gets disengaged from stationary contacts. This
assures the safety of the person working in front of the panel. The person
will never see live contact even if module is in isolation position since safety
shutter 15 becomes the barrier between live contact and the functional unit.
Similarly, it will allow engaging contacts when module is rack in.
[0057] When the module is removed out for maintenance purpose or
for some other purpose, the safety shutter 15 is in closed condition and dropper contacts are not exposed. In that condition safety shutter can be pushed in manually (Though module is not there), but the dropper contact which are live get exposed. This condition is unsafe for any person working near the panel. To avoid this unsafe condition safety shutter 15 is locked with the help of pad lock lever 21 and the lock 71.

G) ADVANTAGES OF THE INVENTION
[0058] Thus the various embodiments of the present invention provide
a protective safety shutter assembly mechanism for switchboards which
allows locking of safety shutter when the module is not in the compartment.
[0059] The safety shutter assembly of the present invention introduces
a compact mechanism of pad locking which is adapted to be used in compact safety shutters in modules.
[0060] The safety shutter system of the present invention ensures the
safety of the person working in front of the panel when the module is not in the feeder compartment. Also the droppers are exposed if safety shutter mechanism operates manually, which in turn avoids contact of the person with live conductor.
[0061] 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.
[0062] 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 safety shutter assembly in switchboards, the assembly comprising;
a tray:
a pad locking lever assembly; and a safety shutter mechanism
wherein the safety shutter mechanism is mounted above the tray and the pad locking lever mechanism is mounted below the tray.
2. The assembly according to claim 1. wherein the padlock lever assembly
comprises:
a pad lock lever and wherein one end of the pad lock lever is attached to the
tray with a bolt;
at least one limb at a center of the pad lock lever leading in to the safety
shutter mechanism;
an extrusion at one end of the pad lock lever for locking a safety shutter, and
wherein the extrusion at one end of the pad lock lever is larger than a cut out
provided on the tray;
an opening provided on the extrusion at one end of the pad lock lever to lock
the pad lock lever with a lock; and
a projection at one end of the pad lock lever for fixing the pad lock lever to
the tray:.
3. The assembly according to claim 1, wherein the pad lock lever is lifted to pass the limb of pad lock lever into a housing in the safety shutter mechanism during a closed condition.
4. The assembly according to claim 1, wherein the pad lock lever is made of metal.

5. The assembly according to claim 1, wherein the safety shutter mechanism further comprises:
at least one module attached with the housing mechanism; a cam provided in the housing mechanism and wherein the cam is shaped to convert a radial movement to the rotational movement; a connecting pin attached to the cam and wherein one end of the connecting pin is attached to the lever; a lever coupled to the connecting pin; a top shutter connected to at least one end of the lever; a bottom shutter connected to at least one end of the lever; a rivet to connect the top shutter and the bottom shutter with the lever; and a shutter housing enclosing the top shutter and the bottom shutter; wherein a rotational movement of the cam causes the top shutter and the bottom shutter to open during a rack-in position of the module and causes the top shutter and the bottom shutter to close during a rack-out position of the module to provide a safety shutting operation.
6. The assembly according to claim 8, wherein at least one end of the connecting pin is attached to the bottom shutter.
7. The assembly mechanism according to claim 12, wherein the rotational movement of the cam causes a rotation of the connecting pin to induce a force on one side of the lever thereby inducing a force on one side of the bottom shutter.
8. The assembly according to claim 15, 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 the rack-in position of the module.

9. The assembly according to claim 15, wherein the lever transfers the force induced on the lever to the top shutter thereby drawing the top shutter towards the bottom shutter during the rack-out position of the module.