F O R M 2

THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)

1. Title of the invention:
IMPROVED SWITCH DISCONNECTOR MECHANISM WITH MECHANICAL ACTUATION

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:

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to a switch disconnector mechanism for use in switchgear applications. More particularly, the invention relates to an improved switch disconnector mechanism with mechanical actuation. The switch disconnector mechanism as described herein is actuated by a knob means manually. However, the mechanism as described herein and in the appended claimed can be motorized without departing from the scope of the present invention.

BACKGROUND AND THE PRIOR ART

Present invention relates to a mechanical actuation of electrical contacts for a Switch Disconnector. Conventionally, a switch Disconnector is a device comprising of moving contacts, fixed contacts, and a mechanism for mechanical actuation of the contacts. The purpose of the switch Disconnector is to carry, make and break normal current in the circuit. The switch will be either in closed or open condition. Switch is said to be open when there is no contact between the moving and fixed contacts and vice versa. An external mechanical actuation has to be given for operating the switch. For this purpose, a mechanism is provided, which can have manually independent operation.

The invention is an actuating mechanism for contact systems in a switch Disconnector, which is intended to make, break and carry current in electrical installations (switchboards). Most of the Existing mechanisms are based on dead centre concepts and are mainly link based.

US 5736698 provides a manually operated switch device for the control of electrical equipment, wherein the electrical elements of the switch are assembled in a housing and the mechanical elements are mounted on a body piece attached to the housing. At least one linearly transferrable slide member communicates with the body piece, the slide member having contact or guide surfaces adapted to cooperate with the stationary contacts,which is connected to the slide member via at least one spring-type element. A power-spring-arming plate which is movable in parallel relationship with the slide member, in such a manner that during the movement of the power-spring-arming plate, the slide member is moved correspondingly under the force exerted by the power springs. By virtue of this arrangement, the switching phase always occurs in a consistent manner, irrespective of the speed used for rotating the switch operating lever.

The conventional disconnector has the following disadvantages:

• Earlier mechanisms are integral part of contact system itself, which makes it complex for mechanism repair and maintenance.
• Most of the previous mechanisms are dead centre based concepts, which limits the efficiency of operation, by not utilizing the springs to its maximum limits.
• Previous mechanisms were mainly link based concepts, which reduce the velocity of operation due to large friction between moving links.

Therefore there is a need to provide a disconnector which overcomes the disadvantages of the conventional disconnector mechanism. The present invention therefore provides a disconnector mechanism wherein mechanism can be given as a separate module, which makes it easier to assemble or dismantle for repair and maintenance. The inventors have found that there still remain a scope of improvement in the existing switch disconnector mechanisms which would be able to address the problems faced in the prior art mechanism and provide the industries with switch disconnector mechanism having enhanced efficient operation. In this mechanism stored energy concept is used, which assures better, rigid and efficient operation. Also to reduce the sliding parts and in turn to minimize the friction, more of cam and gear based assemblies are employed in this present mechanism. The stored energy spring concept is known in the art, however, the prior art fails to teach any mechanism which could increase the efficiency and speed of operation by using less number of mechanism components/parts. The mechanism of the present invention has been provided with certain unique profiles and co-operation of components/parts which has resulted in enhanced efficient and fast operation.

OBJECTS OF THE INVENTION

A basic object of the present invention is to overcome the disadvantages/drawbacks of the known art.

Another object of the present invention is to increase the operating velocity by minimizing the friction which can be attained by using more of cam and gear based assemblies and by reducing the sliding parts.

Another object of the present invention is to utilize stored energy concept for mechanism operation.

These and other advantages of the present invention will become readily apparent from the following detailed description read 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.

There is provided an improved switch disconnector mechanism.

According to one embodiment of the present invention, there is provided to an improved switch disconnector mechanism for use in switchgear operations, said disconnector mechanism comprising:
a top housing and a bottom housing for securing other components/parts of the mechanism;
a knob means fixed on the said top housing such that said knob means is operable by a user for ON or OFF operations;
sub assembly 1 comprising a top moving plate means and a bottom moving plate means, wherein said moving plate means having substantially rectangular cut outs such that placing of said top moving plate means on the bottom moving plate means defines plural slot profiles and wherein said top moving plate means having plural limb profiles which passes through the said bottom moving plate means,
at least one spring means housed in the said slot profiles;
sub assembly 2 comprising
said top housing having plural slot profiles for operative placement of at least one leaf spring means, and
plural guiding means in said top housing;
driver means in communication with said knob means at its one end and the other end communicating with said bottom moving plate in a manner to provide rack and pinion action between said driver means and said bottom moving plate;
cam assembly comprising at least one cam means and plural spring means whereby said spring means are being guided by the guiding means in the said top housing;
wherein said cam means being movably mounted on said driver means such that said cam means being restricted of being lifted in substantially upward direction during operation;
moving bridge assembly consisting moving contact as present in conventional circuit breaker mechanism;
at least one fixed contact as present in conventional circuit breaker mechanism;
wherein when the said knob means is operated from OFF state to ON state the top moving plate means is stopped by the cam means by said cam spring means and said bottom moving plate means starts moving substantially horizontally resulting in charging of spring means connected between the top moving plate means and the bottom moving plate means
wherein said driver means rotates corresponding to the rotation of said knob means thereby charging the leaf spring means;
wherein said spring means connected between the top moving plate means and the bottom moving plate means reaches almost its final charging position by rotation of the knob means through a desired angle whereby said driver means releases the said cam means from stopping the top moving plate means thereby moving said top moving plate means which results in operative engagement of said limb profiles with the moving bridge assembly thereby moving the moving contact to come in contact with the fixed contact.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

So that those having ordinary skill in the art will more readily understand how to construct an improved switch disconnector mechanism for use in switchgears in accordance with the present disclosure, exemplary embodiments are described in details herein below with reference the accompanying drawings wherein:

Fig 1 illustrates the exploded view of the present invention.

Fig 2 illustrates the mechanism where the two springs has been connected to the Top moving plate and Bottom moving Plate.

Fig 3 illustrates the mechanism where the Leaf springs are placed in the slot provided in Top Housing.

Fig 4 illustrates the Driver having a unique profile which will stop/arrest the movement of cam from lifting up.

Fig 5 illustrates the a Gear profile in Bottom moving plate will help in achieving rack and pinion connection between driver and bottom moving plate.

Fig 6 illustrates a Top moving plate having two unique profiles.

Fig 7 illustrates the mechanism components placed on the Middle housing.

Fig 8 illustrates the different views of mechanism in OFF state.

Fig 9 illustrates the use of knob for rotating the driver in clockwise direction.

Fig 10 illustrates the different views when the mechanism is operated from OFF to ON state.

Fig 11 illustrates the different views of the mechanism when the mechanism is operated from OFF to ON state.

Fig 12 illustrates the different views of mechanism during CAM operation.

Fig 13 illustrates the different views of the mechanism when the mechanism reached its final position from OFF to ON state.

Fig 14 illustrates the different views of the mechanism in ON state.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.

Accordingly in the present invention a knob is given, for the mechanism to actuate the contact systems of a switch Disconnector. Knob rotation is constrained to 90 degrees. Rotation of 0-900 attains switching ON and vice versa for Switch OFF. When the operator rotates the knob from 0-900 the spring gets charged till 720 thereafter releasing the cam due to the cam profile, which allows the moving contacts to move linearly and make the contact. The remaining 180 movement is given by the leaf spring, which holds the knob at either ON or OFF position. Same phenomenon is applicable for reverse operation of knob, from 90-00.

Construction:
Switch Disconnector is divided into 2 main divisions. On top it has the mechanism, and below that, it has the contact systems. The mechanism gives the required energy, when operated by an operator to close and open the contact system. Figure 1 shows the exploded view of the entire Switch Disconnector.

1 Knob
2 Top Housing
3 Cam Spring
4 Cam
5 Leaf Spring
6 Driver
7 Top Moving plate
8 Bottom Moving plate
9 main Springs
10 Middle Housing
11 Contact Springs
12 Contact Spring Holders
13 Moving Bridge
14 Moving Contacts
15 Fixed Contacts
16 Bottom Housing

Figure 2 shows the sub mechanism-1, where the two springs has been connected to the Top moving plate and Bottom moving Plate.

Figure 3 shows the sub mechanism-2, here the Leaf springs are placed in the slot provided in Top Housing. The cam springs are placed on the guide in Top housing.

Figure 4 shows a Driver having a unique profile which will stop/arrest the movement of cam from lifting up. When it is rotated along the axis with help of Knob and also the gear profile make this driver to act as a pinion. The driver comprises plural flange means which stop the movement of the cam means.

Figure 5 shows a Gear profile in Bottom moving plate will help in achieving rack and pinion connection between driver and bottom moving plate.

Figure 6 shows a Top moving plate having two unique profiles.
1).The cam profile at the top of the top moving plate will act as self releasing latch, when it is stopped by the cam.
2).The cam profile at bottom of the two limbs which are used to lift the moving bridge in turn open and close the contacts.

Figure 7 shows how the mechanism components placed on the Middle housing. On the Middle Housing the driver is placed on the hole in the middle housing. Then the sub mechanism – 1, is placed on the middle housing. The cam is placed on the top of the Sub mechanism-1. Then the sub-mechanism 2 is placed on the top of the middle housing

Figure 8 (a) shows the top view of the mechanism when it is in OFF state. i.e. When the moving contact is isolated from the fixed contact. In Off state the springs connected between the top moving plate and bottom moving plate is compressed to certain force. The top moving plate is stopped by the cam with help of cam springs. The driver is placed between the leaf springs; this will retain the driver at 90 so that it ensures the position of bottom moving plate.

Figure 8 (B) shows the lateral view of the mechanism when it is in OFF State. The limbs at the top moving plate are connected to the moving bridge. This held the moving bridge in OFF state. The moving contacts are connected to moving bridge with help of spring holder and spring. This is normal state. (i.e., uncompressed spring)

Figure 9 (a) shows the top view of the mechanism when the mechanism is operated from OFF to ON state. For this operation the operator should use knob for rotating the driver in clockwise direction. As a result of this following reactions are taken place in the mechanism. The moving plate is stopped by the cam with help of cam springs. Due to the rack and pinion connection the bottom plate will start moving horizontally which results in charging of spring connected between the top moving plate and the bottom moving plate. The unique profile in driver also helps in stopping the cam from lifting up. The leaf spring gets charged due to the driver rotation .

Figure 9 (b) shows the lateral view of the mechanism, when the mechanism is operated from OFF to ON state. Since the top moving plate is stopped by the cam with help of springs and driver. The Top moving plate held at the initial position only. So Moving bridge cannot move, this ensures the OFF state of the mechanism.

Figure 10(a) shows the top view of the mechanism when the mechanism is operated from OFF to ON state. Here the operator further rotates the driver in clockwise direction. As a result of this following reactions are taken place in the mechanism. The springs connected between the top moving plate and bottom moving plate attains it final charging condition. The unique profile in driver releases the cam from stopping the bottom moving plate.

Figure 10 (b) shows the lateral view of the mechanism, when the mechanism is operated from OFF to ON state. Since the springs between the top moving plate and bottom moving plate attained its fully charged condition. The force acting the top moving plate due to the spring force tries to lift up the cam.

Figure 11(a) shows the top view of the mechanism when the mechanism is operated from OFF to ON state. Here the driver releases the cam, which result in following reactions is in the mechanism. The springs connected between the top moving plate and bottom moving plate attains it full charged condition. The unique profile in the driver releases the cam, but still the cam spring force is acting on the cam. At the same time the force acting on the top moving plate tries to move the top moving plate. Due to the cam profile in the top plate and the cam, the force in the top moving plate is utilized to lift the cam up. As shown in the figure below. This latch releasing action is what we call as self latch releasing arrangement.

Figure 11 (b) shows the lateral view of the mechanism, when the mechanism is operated from OFF to ON state. Due to the spring force in the top moving plate. The top moving plate starts moving. This results in lifting the moving bridge along with the moving contact mechanism.

Figure 12 (a) shows the top view of the mechanism when the mechanism crossed the cam releasing point from OFF to ON state. Here the top moving plate moves along with the moving bridge due to the spring energy stored between top and bottom moving bridge.

Figure 12 (b) shows the lateral view of the mechanism when the moving bridge starts the physical contact between fixed and moving contact. Due to the moving bridge movement the moving contact comes in to contact with the fixed contact.

Figure 13 (a) shows the top view of the mechanism when the mechanism reached its final position from OFF to ON state. Here the bottom moving plate reaches its final position due to spring force on the leaf spring. This in turn moves the top moving plate along the moving bridge.

Figure 13(b) shows the lateral view of the mechanism when the moving contact starts the giving contact pressure. Due to the leaf spring action the moving bridge further lifts up. This in turn compresses the contact spring through spring holder. This develops the required contact pressure on the system.

Figure 14 (a) shows the top view of the mechanism when the mechanism in ON state. After top moving plate reaches its final position, the cam gets down and stops the movement of the top moving plate due to spring force on the cam spring. This state of the switch is called ON State.

Figure 14 (b) shows the lateral view of the mechanism, when the Switch is in ON State. Now the contact spring develops the required contact pressure and thus this state is called as the ON state of the switch.

ADVANTAGES:
a) Compact mechanism with manual independent operation.
b) Modular mechanism.
c) High velocity mechanism
d) Self latch releasing arrangement.

Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein with modifications. However, all such modifications are deemed to be within the scope of the claims.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.

WE CLAIM

1. An improved switch disconnector mechanism for use in switchgear operations , said disconnector mechanism comprising:
a top housing and a bottom housing for securing other components/parts of the mechanism;
a knob means fixed on the said top housing such that said knob means is operable by a user for ON or OFF operations;
sub assembly 1 comprising a top moving plate means and a bottom moving plate means, wherein said moving plate means having substantially rectangular cut outs such that placing of said top moving plate means on the bottom moving plate means defines plural slot profiles and wherein said top moving plate means having plural limb profiles which passes through the said bottom moving plate means,
at least one spring means housed in the said slot profiles;
sub assembly 2 comprising
said top housing having plural slot profiles for operative placement of at least one leaf spring means, and
plural guiding means in said top housing;
driver means in communication with said knob means at its one end and the other end communicating with said bottom moving plate in a manner to provide rack and pinion action between said driver means and said bottom moving plate;
cam assembly comprising at least one cam means and plural spring means whereby said spring means are being guided by the guiding means in the said top housing;
wherein said cam means being movably mounted on said driver means such that said cam means being restricted of being lifted in substantially upward direction during operation;
moving bridge assembly consisting moving contact as present in conventional circuit breaker mechanism;
at least one fixed contact as present in conventional circuit breaker mechanism;
wherein when the said knob means is operated from OFF state to ON state the top moving plate means is stopped by the cam means by said cam spring means and said bottom moving plate means starts moving substantially horizontally resulting in charging of spring means connected between the top moving plate means and the bottom moving plate means
wherein said driver means rotates corresponding to the rotation of said knob means thereby charging the leaf spring means;
wherein said spring means connected between the top moving plate means and the bottom moving plate means reaches almost its final charging position by rotation of the knob means through a desired angle whereby said driver means releases the said cam means from stopping the top moving plate means thereby moving said top moving plate means which results in operative engagement of said limb profiles with the moving bridge assembly thereby moving the moving contact to come in contact with the fixed contact.

2. Mechanism as claimed in claim 1 wherein said bottom moving plate means comprising linear gear profile.

3. Mechanism as claimed in claim 1 wherein said driver means comprising a gear profile such that the said gear profile co-operate with said linear gear profile of the bottom moving plate means.

4. Mechanism as claimed in claim 1 wherein said driver means further comprising at least one flange means adapted to stop of cam movement.

5. Mechanism as claimed in claim 1 wherein said top moving plate comprising at least one cam projection means providing self releasing latch action.

6. Mechanism as claimed in claim 5 wherein said cam projection means is substantially convex quadrilateral such that the resultant spring force acting on it is in an upward direction providing an uplift to said top moving plate means.

7. Mechanism as claimed in claim 1 wherein said limbs of the top moving plate means comprising cam profile adapted for lifting the moving bridge.
8. Mechanism as claimed in any preceding claim comprising at least one contact spring means.

9. Mechanism as claimed in any preceding claim comprising at least one contact spring holder means.

10. Mechanism as claimed in claim 1 wherein said spring means located in between the said top moving plate means and said bottom moving plate means attains its fully charged position through about 72° rotation of the knob.

11. Mechanism as claimed in claim 1 wherein said leaf spring means adapted to provide about 18° movement of said knob to either OFF or ON position.

12. An improved switch disconnector mechanism with mechanical actuation as herein described and illustrated with reference to accompanying drawings.