FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: SAFETY SHUTTER MECHANISM WITHOUT SPRING IN OPEN DOOR OPERATION OF MCC MODULE
2. Applicants):

(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 safety shutter for motor control center. More particularly the present invention relates to a safety shutter mechanism without spring in open door operation of motor control center (MCC) module.
BACKGROUND AND PRIOR ART OF THE INVENTION
Safety shutter is a mechanism which isolate live conductor like droppers from functional unit like module when it is not in service position. This safety shutter is nothing but a barrier between live contact and the functional unit.
Motor control center receives power from power control center and feed it to a number of load points, majority of them are motors operating on an electrical installations. It is a multi compartment with a common bus system to distribute power. On a common bus system motor control units are mounted individually to feed respective motors. These individual feeders normally called as 'modules'. Individual feeders are typically constructed as withdrawable, semi-withdrawable, and plug-in and it contains motor controlling, protection and monitoring equipments.
When modules are operated, it connects/disconnects the incoming bus to motor through control and protection equipment's.
Safety shutter is a mechanism, which isolate live conductor like droppers from functional unit like module when it is not in service position. Functional unit has 3 different positions service, test and isolation. In service condition moving contacts are engaged with stationary conductor whereas in test and isolation both are disengaged. When module is in service and test conditions, it should be isolated from live conductor.
In open door operation of the module, power contacts are moving with the module. Thus, the care has to be taken such that the power contacts will not hit the safety shutter at any position. Operating the safety shutter mechanism is operated once the module is inserted in isolated condition will take care of this condition.
The present inventors found that for open door operation of MCC module, when module is in isolation, the safety shutter completely opens. When the module is moving form isolated to test to service position, the safety shutter remains open. When the module is racking out, the position of the module will change from service to test to isolation. In all these positions, the safety

shutter will remain open. But as soon as it conies out of isolated position, the safety shutter
closes immediately.
This assured 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. Vice versa it will allow engaging contacts when module is
racked in.
The present mechanism is used for safety shutter in any product.
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 a lever, which will operate the safety shutter
mechanism when the module is inserted and comes to isolated position.
Another object of the present invention is to provide a safety shutter mechanism without spring
in open door operation of motor control center (MCC) module.
Yet another object of the present invention is to provide in open door operation of the module
where the safety shutter mechanism has to be operated with the help of one lever.
Yet another object of the present invention is to provide a operation of the safety shutter
mechanism is independent of spring or gravity.
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 the system is provided a safety shutter mechanism without spring in open door operation of motor control center (MCC ) module, said mechanism comprising: a tray means;

a module base means operatively connected with said tray means;
a lever means mounted on said tray means; and
a pin means mounted at the bottom of said module base means at the rear side of said module
base means.
Other aspects, advantages, and salient features of the invention will become apparent to those
skilled in the art from the following detailed description, which, taken in conjunction with the
annexed drawings, discloses exemplary embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a safety shutter mechanism without spring in open door operation of motor control center (MCC) module.
The safety shutter mechanism is operated once the module is inserted in isolated condition. Afterwards, during the operation of the module from isolated to test to service, the lever will operate in such a way that the safety shutter mechanism will remain in the same position and the safety shutter will remain open. Similarly, while operating the module from service to test to isolated, the lever will ensure that the safety shutter will remain open throughout the operation of the module, Once the module is withdrawn, the safety shutter mechanism will operate closing the shutter and ensuring the prevention of the direct contact between live busbar and the person operating the module. The total operation of safety shutter is independent of spring. The present invention provides in open door operation of the module, the safety shutter mechanism operated with the help of one lever. The condition of operating the safety shutter mechanism is that, the safety shutter is open when the module comes in isolated position. The shutter remains open when the module is operated from isolated to test to service and vice a versa. The safety shutter closes when the module is taken out of the panel beyond isolated position ensuring that no live part is accessible. The safety shutter mechanism is independent of spring or gravity.
According to one of the embodiment of the present invention there is provided a safety shutter mechanism without spring in open door operation of motor control center (MCC) module. The mechanism comprising a tray means, a module base means operatively connected with and tray means, a lever means mounted on and tray means and a pin means mounted at the bottom of and module base means at the rear side of and module base means.

The module base means comprises a fixed means mounted on and tray means and a plunger means adapted to move horizontally along the tray means to operate safety shutter. The plunger means comprises of a collar and neck at the rear end of and plunger means. The lever means comprises a cam means having a slot with substantially zig-zag profile ( point 1 of lever and point 2 of lever) for the movement of lever and cam means having pair of guiding pin means of lever means are positioned on diagonally opposite side of sad clam slot means to assist the mounting of and lever on and tray means, an extension means having a substantially U-shaped modular profile welded on front side of and lever means adapted to get locked with the neck of and plunger means .
The cam means is for depth wise movement of and plunger means.
The tray means comprises plurality of slot means having substantially 'Z' like profile (point 1 of slot, point 2 of slot and point 3 of slot) adapted for horizontal and depth wise movement of and lever means.
The module base means movement results in the insertion of and pin means in cam slot means of
lever means adapted for movement of lever means.
The pin means moves in and cam means.
The pin means moves and lever horizontally and depth wise.
The pin moving from point 1 to 2 of lever pushes lever horizontally.
The pin moving beyond point 2 of lever pushes lever depth wise.
The lever when in depth-wise motion pushes and plunger means and opening of safety shutter.
The guiding pin of lever means reaches point 2 of slot and depth-wise movement of lever means
gets stopped and horizontal movement starts.
The lever means move horizontally and the guiding pin reach at point 3 of the slot on the tray
adapted for at this point, the module has reached isolated position and safety shutter remains
open.
The lever means do not move after point 3 of slot means and safety shutter remains open as long
as module is moving from isolated to test to service and reverse way.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The above and other aspects, features, and advantages of certain exemplary embodiments of the
present invention will be more apparent from the following description taken in conjunction with
the accompanying drawings in which:
Figure 1 illustrates the safety shutter mechanism.
Figure 2 illustrates the M.S. lever mounted on the tray with the help of 2 pins.
Figure 3 illustrates the extension of the lever which is welded to the lever on the front side
Figure 4 illustrates the assembly of the lever and the extension will look.
Figure 5 illustrates the pin which is getting mounted at the bottom side of the module base.
Figure 6 illustrates the top view of the tray.
Figure 7 illustrates the pin will always align that lever at the initial condition.
Figure 8 illustrates the pin will push the lever horizontally.
Figure 9 illustrates the plunger of the safety shutter mechanism.
Figure 10 illustrates the movement of pin which is fixed at the bottom of the module base of the
lever.
Fig. 11 illustrates the condition when the module has travelled from Isolated position to service
position.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity
and clarity and may have not been drawn to scale. For example, the dimensions of some of the
elements in the figure may be exaggerated relative to other elements to help to improve
understanding of various exemplary embodiments of the present disclosure.
Throughout the drawings, it should be noted that like reference numbers are used to depict the
same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWING
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be

made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness. The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a tray means" or "a pin means" or "a lever means" includes reference to one or more of such means. By the term "substantially" it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
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 system and method has been discussed below to describe the way it operates. However, such description should not be considered as any limitation of scope of the present system. 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.
Construction:
The main embodiment of the present invention consists of Safety shutter operating mechanism, one M.S. lever mounted on the tray with the help of 2 pins and one pin fixed at the bottom side of the MCC module base at the rear side.
Fig.l shows the safety shutter mechanism in which point 1 shows a fixed part which is mounted on the tray and point 2 shows the plunger which moves horizontally along the tray to operate the

safety shutter. The detailed view of the plunger is shown in Fig.l; the plunger has a collar and neck at the rear end.
Fig.2 shows the M.S. lever mounted on the tray with the help of 2 pins. The 2 pins are fixed on the lever at positions shown by point 1. Point 2 shows the cam slot on the lever which is responsible for the movement of the lever resulting in the corresponding depthwise movement of the plunger of the safety shutter mechanism.
Fig.3 shows the extension of the lever which is welded to the lever on the front side. Thus, the assembly of the lever and the extension will look as shown in fig.4. The U-shape profile of the extension gets locked with the neck of the plunger. It always remains locked with the plunger. The plunger is shown in Fig. 1, the plunger has a collar and neck at the rear end. Fig.5 shows the pin which is getting mounted at the bottom side of the module base. The movement of the module will result in the insertion of the pin in the cam slot of the lever resulting in the movement of the lever.
Fig.6 shows the top view of the tray. The slots provided on the tray as shown by point 1, are for guiding the lever while moving on the tray. The slots will allow the horizontal as well as the depth wise movement of the lever. As the operation of the lever is totally independent of spring, the lever can be horizontally anywhere on the tray. But the entry chamfer provided on the lever will ensure that while entering, the pin will always align that lever at the initial condition as shown in fig. 7 by point 1.
When module moves in further, the pin mounted at the bottom of the module base will enter the cam slot of the lever. While moving from point 1 to point 2 of the lever, the pin will push the lever horizontally as shown in fig.8. But there will not be any depth wise movement of the lever. After this point, there is no allowable horizontal movement of the lever. Only depthwise movement of the lever is allowed. So, when the module is pushed in further, the pin mounted at the bottom of the module base will push the lever depthwise pushing the plunger of the safety shutter mechanism in as shown in fig. 9. There will be movement of the pin on the lever from point 1 to point 2 as shown in fig. 9 pushing the lever in depthwise direction. This will push the plunger of the safety shutter mechanism in. This results in the opening of the safety shutter. When the guiding pin on the lever reaches point 2 of the slot (as shown in fig.6), the depthwise movement of the lever is stopped. Now horizontal movement of the lever is allowed. Thus, the pin which is fixed at the bottom of the module base will move from point 2 to point 3 of the lever

as shown in fig. 10. Correspondingly, the lever will move horizontally and the guiding pin will reach at point 3 of the slot on the tray. At this point, the module has reached isolated position. For the movement of the module from isolated to test to service and from service to test to isolated, the safety shutter should remain open. So, the lever should not move after this point even if the module will move in. Thus, the cam slot is provided as shown by point 2 as shown in fig.2. This will allow the module to move in without further movement of the lever. Thus, the safety shutter will remain open as long as the module is moving from isolated to test to service and reverse way. While taking the module out of isolated position, the reverse action will take place. Final position of the pin on the lever when module is taken out completely is point 1 shown in Fig. 6. Direction of depthwise movement of the module is shown by the arrow in fig.l 1
Advantages:
a) Once the module is inserted in the panel, the safety shutter will open when the module is in isolated position and remains open throughout the operation of the module.
b) When module is taken out from the panel, the safety shutter will close ensuring that the live busbars are not directly accessible.
c) The operation of the safety shutter is independent of spring.
Features:
a) Safety of the operator when module is not in the panel.
b) Shutter will remain open throughout the operation of the module ensuring that the power contacts will not hit the shutter in any position of the module.
c) The operation of the safety shutter is independent of spring or gravity.

WE CLAIM:
1. A safety shutter mechanism without spring in open door operation of motor control
center (MCC) module, said mechanism comprising:
a tray means;
a module base means operatively connected with said tray means ;
a lever means mounted on said tray means; and
a pin means mounted at the bottom of said module base means at the rear side of
said module base means
wherein said module base means comprises a fixed means mounted on said tray
means and a plunger means adapted to move horizontally along the tray means to
operate safety shutter.
2. Mechanism as claimed in claim 1 wherein said plunger means comprising a collar and neck at the rear end of said plunger means.
3. Mechanism as claimed in claim 1 wherein said lever means comprising
a cam means having a slot with substantially zig-zag profile ( point 1 of lever and point 2 of lever) adapted for movement of said lever, said cam means having; pair of guiding pin means of lever means are positioned on diagonally opposite side of sad clam slot means adapted to assist the mounting of said lever on said tray means;
an extension means having a substantially U-shaped modular profile welded on front side of said lever means adapted to get locked with the neck of said plunger means.
4. Mechanism as claimed in claim 3 wherein said cam means is adapted for depth wise
movement of said plunger means.

5. Mechanism as claimed in claim 1 wherein said tray means comprising plurality of slot
means having substantially 'Z' like profile (point 1 of slot ,point 2 of slot and point 3 of
slot) for horizontal and depth wise movement of said lever means.
6. • Mechanism as claimed in claim 1 wherein said module base means moves so as to
provide insertion of said pin means in cam slot means of lever means adapted for movement of lever means.
7. Mechanism as claimed in claim 1 wherein said pin means moves in said cam means.
8. Mechanism as claimed in claim 7 wherein said pin means moves said lever horizontally and depth wise.
9. Mechanism as claimed in claim 7 wherein said pin moving from point 1 to 2 of lever pushes lever horizontally.
10. Mechanism as claimed in claim 7 wherein said pin moving beyond point 2 of lever pushes lever depth wise.
11. Mechanism as claimed in any of the preceding claims wherein said lever in depth-wise motion pushes said plunger means and opening of safety shutter.
12. Mechanism as claimed in any of the preceding claims wherein said guiding pin of lever means reaches point 2 of slot and depth-wise movement of lever means gets stopped and horizontal movement starts.
13. Mechanism as claimed in claim 1 wherein said lever means move horizontally and the guiding pin reach at point 3 of the slot on the tray adapted for at this point, the module has reached Isolated position and safety shutter remains open.

14, Mechanism as claimed in claim 13 wherein said lever means do not move after point 3 of
slot means and safety shutter remains open as long as module is moving from isolated to
test to service and reverse way.
15. A safety shutter mechanism without spring in open door operation of motor control
center (MCC) module as herein substantially described and illustrated with the
accompanying drawings.