F0RM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - AN IMPROVED MECHANICAL INTERLOCK, DUAL
TOGGLING AND THREE POSITION MECHANISM OF AN ELECTRICAL LOAD BREAK SWITCH
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:

FIELD OF THE INVENTION
The present invention relates to Electrical Switches. More particularly, the invention is concerned about an improved mechanical interlock, dual toggling and three position mechanism of an electrical load break switch.
BACKGROUND OF THE INVENTION
During service period of a load, it is required to disconnect the load. Here the load should be completely isolated and further it should be earthed for complete protection of the system and the service personal. Thus there is a need to have special switch to attain all the aforesaid requirements, such type of switch is commonly known as LOAD BREAK SWITCH, this type of switch is able to obtain perfect isolation between input power supplies and the load and later totally connecting the load to the earth. Load break switches are very much required and used in electrical engineering.
EP 1912230 (A2) relates to a load disconnecting switch with spring action drive for operation at least a switch contact a mechanism in which the disconnector has an engaging and disengaging spring, a switching shaft (2) and a spring force drive for switching movement engaged at the shaft. Here a shaft supports the switching contact a blocking device is provided for the spring force drive, which maintains the spring in a tightening position before reaching a dead center positioning of the engaging spring. A driver is arranged at the switching shaft in a detachably fixed manner, and a mechanical and/or electrical locking device is provided.
The disadvantages in the prior art are such that the mechanism is cumbersome and requires many components. The assembly requires more number of varieties of components leads to bulky and becomes high cost. Thus, there is a need to overcome the disadvantages of the prior art and also develop load break switch which is optimized in terms of material used and their flexible arrangement. Therefore, the present inventors have developed a mechanical interlock, dual toggling and three position mechanism of an electrical load break switch, which achieves the results including the complete protection

of the load and the servicing personnel in a cost effective manner which is commercially beneficial.
OBJECTS OF THE INVENTION
An object of the present invention is to overcome the problems/disadvantages of the prior art.
Another object of the present invention is to provide an improved mechanical interlock, dual toggling and three position mechanism of an electrical load break switch.
Another object of the present invention is to provide an improved mechanism for isolating the load and further connecting it to the earth.
Another object of the present invention is to provide an improved mechanism for an independent system of closing and opening of contacts.
Another object of the present invention is to provide an improved mechanism for interlocking of two switches and padlocking during the load is earthed.
Another object of the present invention is to provide an improved mechanism with a positive indication for the user.
Yet, another object of the present invention is to provide an improved mechanism by using less number of components and cost effective.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided an improved mechanical interlock, dual toggling and/or three position mechanism of an electrical load break switch, said mechanism comprising:
rotating shaft means (5);
operating handle means (4);
spring arm means (13) having a mechanism spring means (14) ;

a link arrangement (15);
plurality of operating shaft means comprising main switch operating shaft means (11) and earth switch operating shaft means (12);
wherein said main switch operating shaft (11) having substantially cylindrical shape with substantially !C shaped profile being adapted to accommodate the bent portion of a connector of a interlock link (9):
wherein said earth switch operating shaft (12) having substantially cylindrical shape with substantially 'C shaped profile being adapted to accommodate the bent portion of a connector of the interlock link(9);
wherein said link arrangement (15) comprising substantially triangular shaped link connector having substantially circular hole substantially at each of the vertices operatively connected to plurality of link connectors; one of vertices of said triangular shaped link connector operatively connected to a substantially rectangular element; one of the link connectors having substantially linear shape having substantially elongated hole at one end operatively connected to the triangular shaped link connector and substantially circular hole at other end operatively connected to the earth switch operating shaft (12) or main switch operating shaft (11) thereby said link arrangement (15) transferring energy provided by the mechanism spring (14) to the rotating shaft (05);
wherein said spring arm means being substantially wound around with mechanism spring (14) means; said spring arm means (13) operatively connected to said main switch operating shaft means (11) and earth switch operating shaft means (12) thereby transferring force from the spring to the link arrangement (15) to drive the rotating shaft means(5);
wherein the interlock link (09) comprising at least two connectors; each connector being operatively connected to other connector forming substantially 'V shape by means of hinge at one end to facilitate the movement of the assembly; said each connector having substantially linear shape being bended at one end adapted to connect to the main switch

operating shaft means (11) or earth switch operating shaft means (12) when any of the operating shaft is rotated thereby interlocking between main switch and earth switch;
wherein said interlock link (09) being in horizontal position when the main switch operating shaft means (11) and the earth switch operating shaft means (12) are in OFF state:
wherein the main switch operating shaft means (11) being rotated in clockwise direction, the interlock link (09) being pushed by the main switch operating shaft means(l 1) to rotate in clockwise direction thereby barring access to the earth switch operating shaft (12) till the main switch is back to OFF position; when the main switch operating shaft (11) is rotated in anticlockwise direction, the interlock link (09) being pulled by the spring to rotate in anticlockwise direction giving the operating handle (04) access to be inserted in main switch operating shaft (11) or earth switch operating shaft (12) to operate the mechanism (01) resulting in Main switch ON or Earth switch ON respectively;
wherein said earth switch operating shaft (12) being rotated in clockwise direction, the interlock link (09) being pushed by the earth switch operating shaft (12) to rotate in anticlockwise direction thereby barring the access to the main switch operating shaft (II) till the earth switch is back to OFF position; when the earth switch operating shaft (12) being rotated in anticlockwise direction, the interlock link (09) being pushed by the spring to rotate in clockwise direction giving operating handle (04) the access to be inserted in main switch operating shaft (11) or earth switch operating shaft (12) to operate the mechanism (01) resulting in Main switch ON or Earth switch ON respectively.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 illustrates a switch as per one embodiment of the present invention.
Fig. 2 illustrates an exploded view of switch as per one embodiment of the present invention.
Fig. 3 illustrates a front view of the Mechanism (01).
Fig. 4 illustrates an isometric view of the Mechanism (01) with a mounting arrangement with switch (02).
Fig. 5 illustrates an isometric view of the Mechanism (01) with a pad locking arrangement (07).

Fig. 6 illustrates an isometric view of the Mechanism (01) with a pad locking arrangement (07) with plate (08) removed.
Fig. 7 illustrates a front view of the Mechanism (01) with mechanism plate (08) removed and both switches in OFF position.
Fig. 8 illustrates a front view of the Mechanism (01) with main switch (11) in ON position thereby rotating the interlock link (09) in clockwise direction.
Fig. 9 illustrates a front view of the Mechanism (01) with one of the mechanism plate (08) removed and both the switch in OFF position.
Fig. 10 illustrates a front view of the Mechanism (01) with Earth switch (12) is in ON position thereby rotating the interlock link (09) in anticlockwise direction.
Fig. 11 illustrates an isometric view of the Mechanism (01) with mechanism plate (08), pad locking arrangement (07) and interlock link (09) removed.
Fig. 12 illustrates an isometric view of the Mechanism (01) with two mechanism plates (08) removed further.
Fig. 13 illustrates a front view of the Mechanism (01) with mechanism plates (08) removed further.
Fig. 14 illustrates a front view of the Mechanism (01) with main switch operating shaft (11) is rotated in clockwise direction up to the dead center of the mechanism (01).
Fig. 15 illustrates a front view of the Mechanism (01) with main switch (11) in ON position.
Fig. 16 illustrates a front view of the Mechanism (01) with one more mechanism plate (08) removed further, showing the spring arm (13), mechanism spring (14), main switch operating shaft (11) and earth switch operating shaft (12) when both switches are in OFF position.
Fig. 17 illustrates a front view of the Mechanism (01) with earth switch operating shaft (12) is rotated in clockwise direction up to the dead center of the mechanism (01).
Fig. 18 illustrates a front view of the Mechanism (01) with earth switch (12) in ON position.
Fig. 19 illustrates a front view of the Mechanism (01) with mechanism plates (08), spring arm (13), and mechanism spring (14) removed with main and earth switch in OFF position
Fig. 20 illustrates a front view of the Mechanism (01) with mechanism plates (08), spring arm (13), and mechanism spring (14) removed.

Fig. 21 illustrates a front view of the Mechanism (01) with one more mechanism plate (08), spring arm (13). and mechanism spring (14) removed further with the main switch (11) in OFF position and earth switch (12) in ON position.
Fig. 22 illustrates an isometric view of the Mechanism (01) with one more mechanism plate (08), spring arm (13) and mechanism spring (14) removed showing the link arrangement to drive the rotating shaft (15) with main switch (11) and earth switch (12) both In OFF position.
Fig. 23 illustrates an isometric view of the Mechanism (01) with the motion transfer plate (16), rotating shaft (05) and ball bearing arrangement (17) to hold the operating shaft in position.
Fig. 24 illustrates a front view of the mechanism (01) with both Main switch & earth switch in OFF position.
Fig. 25 illustrates an isometric view of the mechanism (01) with both Main switch & earth switch in OFF position.
Fig. 26 illustrates a front view of the mechanism (01) with Main switch OFF & earth switch in ON position, pad lock lever (19) held in a position by means of a spring.
Fig. 27 illustrates a front view of the mechanism (01) with Main switch OFF & earth switch in ON position, pad lock lever (19) is pulled to a position barring the access to the earth switch operating shaft (12).
Fig. 28 illustrates an isometric view of the mechanism (01) with Main switch OFF & earth switch in ON position, pad lock lever (19) is pulled to a position barring the access to the earth switch operating shaft (12).
Fig. 29 illustrates an isometric view of the mechanism (01) with Main switch OFF & earth switch in ON position, pad lock lever (19) is pulled to a position barring the access to the earth switch operating shaft (12). Lock latch 1 (20) held in a position by means of a spring. Fig. 30 illustrates an isometric view of the mechanism (01) with Main switch OFF & earth switch in ON position, pad lock lever (19) is pulled to a position barring the access to the earth switch operating shaft (12). Lock iatch 1 (20) locked with lock latch 2 (21).
The arrangement and engagement of the components are described in greater details in the following paragraphs for better understanding of the mechanism and its function at different switching positions.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
According to the invention there is provided an improved mechanical interlock, dual toggling and three position mechanism of an electrical load break switch. The present invention relates to the mechanism used for load break switch that is capable of turning or isolating a load ON and OFF and connecting the load to the earth for complete protection during service period. The mechanism enables the switch to make on overload and break the normal load current. The mechanism adheres to the requirements of a switch being manually independent. The dual toggling, three position mechanisms for a load break switch is obtained in a compact form in this invention along with the provision of earthling the load after breaking the connection of the supply with the load.
The different states of the switch and the related parts thereof are as follows:
Earth/main switch OFF: The state at which the moving contact bridge is in open condition with the mechanism as shown in fig. 6,7,9,11,12,13,16,19 & 22. The interlock link (09) is in horizontal position as shown in fig. 6, 7, 9 & 11 giving operating handle (04) the access to be inserted in main switch operating shaft (11) or earth switch operating shaft (12) to operate the mechanism (01) resulting in Main switch ON or Earth switch ON respectively. The interlock link (09) comprising at least two connectors. Each connector of interlock link is operatively connected to other connector forming substantially 'V shape by means of hinge at one end to facilitate the movement of the assembly. Each connector having substantially linear shape being bended at one end adapted to connect to the main switch operating shaft means (11) or earth switch operating shaft means (12) when any of the operating shaft is rotated thereby interlocking between main switch and earth switch. The movement and the function of the interlock link (09) with respect to the mechanism (01) operation are explained below. Both main switch operating shaft (11) & earth switch operating shaft (12) are held in position with the help of the mechanism arrangement and the spacer/stopper (18) provided. The main switch operating shaft (11) having substantially cylindrical shape with substantially 'C shaped profile to accommodate the bended portion of a connector of ainterlock link (9). Similarly, the earth switch operating shaft (12) having substantially cylindrical shape with substantially 'C shaped profile to accommodate a bended portion of a connector of the interlock link(9).

The spring arm means substantially covered with mechanism spring (14) means. The spring arm means (13) operatively connected to said main switch operating shaft means (11) and earth switch operating shaft means (12) thereby transferring force from the spring to the link arrangement (15) to drive the rotating shaft means(5).As shown in figure 5, the mechanism comprises plurality of plates means (8) namely plate-I (8a), plate-TI (8b), and plate-III (8c). The link arrangement (15) and spring arm means (13) are located on the plate I (8a). The interlock link (09) is located on said plate II(8b).
The pad locking arrangement (07) is held in position as shown in fig. 3, 5, 6,7,8,9 & 10 thereby providing access for the earth switch operating shaft (12). The padlock arrangement (7) is located on said plate 111 (8c).The movement and the function of the pad locking arrangement (07) with respect to the mechanism (01) operation are explained below.
Main switch ON: The handle is rotated in the clockwise direction for the OFF to ON operation as shown in Fig 8, 14 & 15. This rotation is transferred through the main switch operating shaft through the link arrangement (15) to the rotating shaft. The link arrangement (15) comprises substantially triangular shaped link connector, which is having substantially circular hole substantially at each vertice operatively connected to plurality of link connectors. One of vertices of the triangular shaped link connector operatively connected to a substantially rectangular element. One of the link connectors having substantially linear shape having substantially elongated hole at one end operatively connected to the triangular shaped link connector, one of the link connectors having substantially circular hole at the other end operatively connected to the earth switch operating shaft (12) or main switch operating shaft (11) thereby said link arrangement (15) transferring energy provided by the mechanism spring (14) to the rotating shaft (05).After the dead centre is crossed the spring is allowed to expand and release the energy stored through the spring arm. This operation comes to a halt when the moving contact bridge reaches the desired design location, the main switch is closed & the mechanism is stopped at the spacer/stopper (18). As the bridge is operated from the spring after dead centre the velocity of the contacts depends on the rate at which spring discharges required energy.
Fig. 14 shows the main switch operating shaft (11) rotated clockwise partially till the dead center; here the link arrangement (15) is pushed from right hand side to the left hand side

of the mechanism (01) as compared to fig. 13 with the help of the link from the link arrangement (15) connected to the main switch operating shaft (11), thereby transferring the motion to the rotating shaft (05) behind the mechanism causing the moving contact bridge to rotate.
Fig. 15 shows the main switch operating shaft (11) rotated completely and is stopped by the spacer/stopper (18). Here the link arrangement (15) is pushed further from right hand side to the left hand side of the mechanism (01) as compared to fig, 14 with the help of the link from the link arrangement (15) connected to the main switch operating shaft (11), thereby transferring the motion to the rotating shaft (05) behind the mechanism causing the Main switch to close.
As the main switch operating shaft (11) is rotated clockwise the interlock link (09) is push by the main switch operating shaft (11) to rotate in clockwise direction as shown in fig. 8, thereby barring the access to the earth switch operating shaft (12) till the Main switch is back to OFF position. The interlock link (09) is pushed by a unique cut provided on the main switch operating shaft (11) as shown in fig. 6, 11, 12 & 22. The interlock link is spring loaded. Thus the unique interlocking arrangement provides an interlock in between the Main and the earth switch.
Main switch OFF: Similarly the handle is rotated in anticlockwise direction for the ON to OFF operation. This rotation is transferred through the main switch operating shaft through the link arrangement (15) to the rotating shaft. After the dead centre is crossed the spring is allowed to expand and release the energy stored through the spring arm. This operation comes to a halt when the moving contact bridge reaches the desired design location, the main switch is opened & the mechanism is stopped at the spacer/stopper (18). As the bridge is operated from the spring after dead centre the velocity of the contacts depends on the rate at which spring discharges required energy.
Fig. 14 shows the main switch operating shaft (11) rotated anticlockwise partially till the dead center; here the link arrangement (15) is pushed from left hand side to the right hand side of the mechanism (01) as compared to fig.15 with the help of the link from the link arrangement (15) connected to the main switch operating shaft (11), thereby transferring

the motion to the rotating shaft (05) behind the mechanism causing the moving contact bridge to rotate.
Fig. 13 shows the main switch operating shaft (11) rotated completely and is stopped by the spacer/stopper (18). Here the link arrangement (15) is pushed further from left hand side to the right hand side of the mechanism (01) as compared to fig. 14 with the help of the link from the link arrangement (15) connected to the main switch operating shaft (11), thereby transferring the motion to the rotating shaft (05) behind the mechanism causing the Main switch to open.
As the main switch operating shaft (11) is rotated anticlockwise the interlock link (09) is pulled by the spring to rotate in anticlockwise direction as shown in fig. 6, 7 & 9 giving operating handle (04) the access to be inserted in main switch operating shaft (11) or earth switch operating shaft (12) to operate the mechanism (01) resulting in Main switch ON or Earth switch ON respectively.
Earth switch ON: The handle is rotated in the clockwise direction for the OFF to ON operation as shown in Fig 10, 17 & 18. This rotation is transferred through the earth switch operating shaft through the link arrangement to the rotating shaft. After the dead centre is crossed the spring is allowed to expand and release the energy stored through the spring arm. This operation comes to a halt when the moving contact bridge reaches the desired design location, the earth switch is closed & the mechanism is stopped at the spacer/stopper (18). As the bridge is operated from the spring after dead centre the velocity of the contacts depends on the rate at which spring discharges required energy.
Fig. 17 shows the earth switch operating shaft (12) rotated clockwise partially till the dead center; here the link arrangement (15) is pushed from left hand side to the right hand side of the mechanism (01) as compared to fig. 16 with the help of the link from the link arrangement (15) connected to the earth switch operating shaft (12), thereby transferring the motion to the rotating shaft (05) behind the mechanism causing the moving contact bridge to rotate.
Fig. 18 shows the earth switch operating shaft (12) rotated completely and is stopped by the spacer/stopper (18). Here the link arrangement (15) is pushed further from left hand

side to the right hand side of the mechanism (01) as compared to fig. 17 with the help of the link from the link arrangement (15) connected to the earth switch operating shaft (12), thereby transferring the motion to the rotating shaft (05) behind the mechanism causing the earth switch to close.
As the earth switch operating shaft (12) is rotated clockwise the interlock link (09) is push by the earth switch operating shaft (12) to rotate in anticlockwise direction as shown in fig. 10, thereby barring the access to the main switch operating shaft (11) till the earth switch is back to OFF position. The interlock link (09) is pushed by a unique cut provided on the earth switch operating shaft (12) as shown in fig. 6, 11, 12 & 22. The interlock link is spring loaded. Thus the unique interlocking arrangement provides an interlock in between the Main and the earth switch.
Initially when the Earth switch is in OFF position, the spring loaded pad lock lever (19) is held in position by means of a spring as shown in fig. 24 & 25. When the earth switch is operated as shown in fig. 26 the pad lock lever is pulled to the position as shown in fig. 27 & 28, thereby barring the access to the earth switch operating shaft (12). Thus the earth switch can only be operated once the pad lock lever (19) is pulled back to its position as shown in fig. 24 & 25.
Fig. 29 shows Lock latch 1 (20) & lock latch 2 (21), initially lock latch 1 (20) is held in position as shown in fig. 29 by means of a spring. Once the pad lock lever (19) is pulled to a position as shown in fig. 27 & 28 after the earth switch is operated, the lock latch 1 (20) is rotated as shown by the arrow direction in fig. 29 and is locked to lock latch 2 (21) as shown in fig. 30. Thereby ensuring the position of pad lock lever (19) so that earth switch is not operated once it is in ON condition.
Earth switch OFF: Similarly the handle is rotated in anticlockwise direction for the ON to OFF operation. This rotation is transferred through the earth switch operating shaft through the link arrangement to the rotating shaft. After the dead centre is crossed the spring is allowed to expand and release the energy stored through the spring arm. This operation comes to a halt when the moving contact bridge reaches the desired design location, the earth switch is opened & the mechanism is stopped at the spacer/stopper (18).

As the bridge is operated from the spring after dead centre the velocity of the contacts depends on the rate at which spring discharges required energy.
Fig. 17 shows the earth switch operating shaft (12) rotated anticlockwise partially till the dead center; here the link arrangement (15) is pushed from right hand side to the left hand side of the mechanism (01) as compared to fig.18 with the help of the link from the link arrangement (15) connected to the earth switch operating shaft (12), thereby transferring the motion to the rotating shaft (05) behind the mechanism causing the moving contact bridge to rotate.
Fig. 16 shows the earth switch operating shaft (12) rotated completely and is stopped by the spacer/stopper (18). Here the link arrangement (15) is pushed further from right hand side to the left hand side of the mechanism (01) as compared to fig. 17 with the help of the link from the link arrangement (15) connected to the earth switch operating shaft (12), thereby transferring the motion to the rotating shaft (05) behind the mechanism causing the earth switch to open.
As the earth switch operating shaft (12) is rotated anticlockwise the interlock link (09) is pushed by the spring to rotate in clockwise direction as shown in fig. 6, 7 & 9 giving operating handle (04) the access to be inserted in main switch operating shaft (11) or earth switch operating shaft (12) to operate the mechanism (01) resulting in Main switch ON or Earth switch ON respectively.
Here the operation of the pad locking arrangement is vice versa as compared to earth switch ON condition. The lock latch 1 (20) is released from lock latch 2 (21), thus rotating in the reverse direction as shown by the arrow in fig. 29 thereby regaining its position. Thus the pad lock lever (19) is also free to regain its position as shown in fig. 24, 25 & 26, thereby give access to the earth switch operating shaft (12) to switch the earth switch to OFF position. Thereby ensuring complete pad locking for the earth switch operation.
ADVANTAGES OF THE INVENTION
1. Complete protection of the load and the service personal
2. Optimized in terms of materials used
3. Cost effective product
4. Flexible/adjustable arrangement for various variants offered

The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The plates, springs, operating shaft, rotating shaft, and connectors as stated do not limit the scope of the present invention. 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.
Following arc the components/terminologies used in the present invention:
1. Mechanism: Mechanism is an arrangement for making main/earth switch ON to OFF and vice versa.
2. Switch: Is an assembly of the contact system, terminals and other supporting parts.
3. Terminals: Arrangement for connection for current transfer.
4. Operating handle: Device used to operate the mechanism.
5. Rotating shaft: Is a part of mechanism which transmits the motion from the mechanism to the moving contact bridge.
6. Gas filling valve: Non return valve used for gas filling.
7. Pad locking arrangement: Is an arrangement where the specific position of the mechanism is locked, so that it cannot be changed unless it is unlocked.
8. Mechanism plate: Metallic plates are used to house the mechanism components.
9. Interlock link: Is a spring loaded arrangement which provides interlock between main switch and earth switch.
10. Spacers: Metallic tubes used for providing a gap between two mechanism plates (08) for friction less movement.
11. Main switch operating shaft: Main switch operating shaft is use to operate the main switch, between ON and OFF position.
12. Earth switch operating shaft: Earth switch operating shaft is use to operate the earth switch, between ON and OFF position.

13. Spring arm: Spring arm is the element that is used to align the mechanism spring (14) to its position and transfer force from the spring to the link arrangement to drive the rotating shaft (05/).
14. Mechanism spring: It is an element used to store and release energy for achieving manual independence of the mechanism. The spring acts as the sole energy provider to the rotating shaft (05) thus achieving a desired velocity of closure for the contacts independent of the user.
15. Link arrangement to drive rotating shaft: The energy provided by the mechanism spring (14) is transferred to the rotating shaft (05) by means of the push pull link arrangement.
16. Motion transfer plate: Motion transfer plate links the link arrangement (15) to the rotating shaft (05), thereby transferring the motion.
17. Ball bearing arrangement: Ball bearing arrangement holds the operating shaft in desired design position.

18. Spacer/stopper: Arrangement to provide and maintain designed spacing in between the mechanism plates & as a stopper for main switch and earth switch in ON & OFF position.
19. Pad lock lever: Is a spring loaded component use to Barr the access to the earth switch operating shaft (12) once the earth switch in ON.

20. Lock latch 1: Is a spring loaded component use to lock the pad lock lever (12) during the pad locking operation.
21. Lock latch 2: Lock latch 2 provides a mean to lock the lock latch 1 (20) as shown in fig.

We Claim
1. An improved mechanical interlock, dual toggling and/or three position mechanism of an electrical load break switch, said mechanism comprising:
rotating shaft means (5);
operating handle means (4);
spring arm means (13) having a mechanism spring means (14);
a link arrangement (15);
plurality of operating shaft means comprising main switch operating shaft means (11) and earth switch operating shaft means (12);
wherein said main switch operating shaft (11) having substantially cylindrical shape with substantially 'C' shaped profile being adapted to accommodate the bent portion of a connector of a interlock link (9);
wherein said earth switch operating shaft (12) having substantially cylindrical shape with substantially 'C' shaped profile being adapted to accommodate the bent portion of a connector of the interlock link(9);
wherein said link arrangement (15) comprising substantially triangular shaped link connector having substantially circular hole substantially at each of the vertices operatively connected to plurality of link connectors; one of vertices of said triangular shaped link connector operatively connected to a substantially rectangular element; one of the link connectors having substantially linear shape having substantially elongated hole at one end operatively connected to the triangular shaped link connector and substantially circular hole at other end operatively connected to the earth switch operating shaft (12) or main switch operating shaft (11) thereby said link arrangement (15) transferring energy provided by the mechanism spring (14) to the rotating shaft (05);
wherein said spring arm means being substantially wound around with mechanism spring (14) means; said spring arm means (13) operatively connected to said main

switch operating shaft means (11) and earth switch operating shaft means (12) thereby transferring force from the spring to the link arrangement (15) to drive the rotating shaft means(5);
wherein the interlock link (09) comprising at least two connectors; each connector being operatively connected to other connector forming substantially 'V shape by means of hinge at one end to facilitate the movement of the assembly; said each connector having substantially linear shape being bended at one end adapted to connect to the main switch operating shaft means (11) or earth switch operating shaft means (12) when any of the operating shaft is rotated thereby interlocking between main switch and earth switch;
wherein said interlock link (09) being in horizontal position when the main switch operating shaft means (11) and the earth switch operating shaft means (12) are in OFF state;
wherein the main switch operating shaft means (11) being rotated in clockwise direction, the interlock link (09) being pushed by the main switch operating shaft means(ll) to rotate in clockwise direction thereby barring access to the earth switch operating shaft (12) till the main switch is back to OFF position; when the main switch operating shaft (11) is rotated in anticlockwise direction, the interlock link (09) being pulled by the spring to rotate in anticlockwise direction giving the operating handle (04) access to be inserted in main switch operating shaft (11) or earth switch operating shaft (12) to operate the mechanism (01) resulting in Main switch ON or Earth switch ON respectively;
wherein said earth switch operating shaft (12) being rotated in clockwise direction, the interlock link (09) being pushed by the earth switch operating shaft (12) to rotate in anticlockwise direction thereby barring the access to the main switch operating shaft (11) till the earth switch is back to OFF position; when the earth switch operating shaft (12) being rotated in anticlockwise direction, the interlock link (09) being pushed by the spring to rotate in clockwise direction giving operating handle (04) the access to be inserted in main switch operating shaft (11)

or earth switch operating shaft (12) to operate the mechanism (01) resulting in Main switch ON or Earth switch ON respectively.
2. The mechanism as claimed in claim 1 further comprising plurality of plates means (8) comprises plate-I (8a), plate-11 (8b), plate-III (8c).
3. The mechanism as claimed in claim 1 further comprising plurality of spacers (10) having substantially tube shape adapted to provide a gap between said plates (8)
4. The mechanism as claimed in claim 1 wherein said link arrangement (15) being adapted to locate on said plate I (8a).
5. The mechanism as claimed in claim 1 wherein said spring arm means (13) being adapted to locate on said plate I (8a)
6. The mechanism as claimed in claim 1 wherein said interlock link (09) being adapted to locate on said plate II(8b).
7. The mechanism further comprising pad locking arrangement (7); said arrangement comprising :
lock latch 1 means(20) ; lock latch 2 means(21); spring means; padlock lever means (19);
when the earth switch is operated, the pad lock lever (19) being pulled such that the pad lock lever (19) being operatively contacted the earth switch, the lock latch 1 means (20) rotated and is locked to lock latch 2 means (21) thereby barring the access to the earth switch operating shaft means (12);
when the earth switch is in OFF position, the lock latch 1 means (20) being released from lock latch 2 means (21) such that the pad lock lever (19) being dis-contacted from the earth switch thereby given access to the earth switch operating shaft (12) to switch the earth switch to OFF position.

8. The mechanism as claimed in claim 7, wherein said padlock arrangement (7) being adapted to locate on said plate III (8c).
9. The mechanism as claimed in claim 1, wherein any of the operating shaft is rotated in clockwise direction
10. The mechanism as claimed in claim 1, wherein any of the operating shaft is rotated in anti-clockwise direction
11. An improved mechanical interlock, dual toggling and/or three position mechanism of an electrical load break switch as herein substantially described and illustrated with the accompanying drawings.