FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
SWITCH OPERATING MECHANISM;
LARSEN & TOUBRO LIMITED, A COMPANY INCORPORATED UNDER THE INDIAN COMPANIES ACT, 1956, WHOSE ADDRESS IS L&T HOUSE, BALLARD ESTATE, MUMBAI -400 001, MAHARASHTRA, INDIA
THE FOLLOWING SPECIFICATION
PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF INVENTION:
This invention relates to the field of switches.
BACKGROUND OF THE INVENTION
A switch is normally used inside an electronic circuit and provides positive contact while eliminating resistor from the circuit. Micro switches are the advanced switches that provide a very efficient way of handling power in newer electronic controllers. A micro switch is basically an electric switch that is actuated by a physical motion of mechanical devices and is generally packaged in a small form factor to allow placement in small spaces. Micro-switches are normally directly operated by a moving member.
Accurate positioning of the switch is necessary to provide an electrical contact without any loss. This is generally achieved by carrying out few adjustments in the mechanisms. However, sometimes accurate positioning of the switch does not take place due to vibrations or human error or handling skill of a worker during the adjustment procedure. The failure of accurate positioning of switch may result is damaged switch &/or non-functioning of the switch. Further, the ON/OFF operation of the switch cannot be checked before using it in any device.
In the state of art, a block is assembled to the rod for adjusting it by moving up and down based on the feel of the assembler. Said block is a cubicle piece with a chamfer on one side. This chamfered side is used for actuating the switch. The assembler adjusts the position of this block on the rod based on the feel. The actuation of the micro switch is not seen, when assembled. Hence the adjustment is based on the operator's past experience.
The block is locked using a locknut. The block is threaded onto the rod. It is locked in place by a standard nut. The block and nut are tightened (locked) against each other. The block without this lock nut can shift from its adjusted position. This can happen due to vibrations during transportation or normal running.
The cover is then assembled with the junction body. The cover hides the switch adjustment within the assembly. The correctness of adjustment is known by switching a pump 'ONV'OFF'. Said Pump is the total dispensing unit used for Petroleum products. The motor and other electronics of the pump starts, when
2

Petroleum products. The motor and other electronics of the pump starts, when the pump is switched 'ON'. For any re-adjustment the cover has to be disassembled. The procedure may be repeated until satisfactory results are achieved.
Thus there is a need for a mechanism in micro switches that allows limited misalignment of the assembly.
SUMMARY OF THE INVENTION:
The present invention provides a switch operating mechanism. A movable actuator protrudes out of the mechanism. The housing of the switch operating mechanism is preferably a molded junction box. The bracket of the new mechanism can be attached to the junction box body. The bracket is also used for mounting a micro switch. The micro switch is adapted within the housing such that it is electrically coupled to the actuator. A link connected to the actuator within the housing is also provided wherein said actuator is moved to rotate the link about a hinge point to actuate the ON-OFF operation of the micro switch without requiring any adjustment in the position of said micro switch thereby allowing least misalignment of the micro switch.
As per the present invention, the actuator within the switch operating mechanism is moved linearly in up and down position to actuate the link. Said link is rotatably joined to the housing through the hinge point. The link is provided with a cam profile on the other side of the hinge point. The micro-switch is turned 'ON' or 'OFF', depending on cam position of the link.
As per the present invention this ON/OFF operation of the micro switch ON/OFF can be checked, before using said micro switch in any device. No adjustment of the micro switch is necessary. Any replacement can be done by removing the cover from the housing and repeating the procedure until a satisfactory result is achieved. This cover is then assembled with the junction body and the switch operating mechanism may be used in various electrical equipments or devices like petrol dispensing unit etc.
Other features, advantages and objects of the invention will be apparent from the following description.
3

BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will now be described by way of example with reference to the accompanying drawings in which:
Figure 1 shows the isometric view of the switch operating mechanism.
Figure 2 shows the exploded view of the switch operating mechanism.
Figure 3 shows the cross sectional view of the isometric view of the switch operating mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
The present invention describes a switch operating mechanism that operates a micro switch. Figure 1 shows the isometric view of the switch operating mechanism. As shown in Figure 1, the micro switch (3) is mounted on a bracket (1). Said bracket (1) is mounted on a housing (8) comprising a junction body (not shown). The operating rod of the micro switch (3) is mounted in a cover (not shown). Said cover and housing (8) together make a junction box.
As per the present invention, to operate the micro switch an external part in this case rod, as mentioned above is moved linearly for actuation. This external part (rod) presses the link (9), which has a cam profile on one side, and a dome shape on the other side. The dome is touching the external part and is hinged. When the link (9) is pressed by the external part, it rotates about the hinge point. The cam profile of the link (9) actuates the micro-switch. Depending upon the position of the cam, the micro-switch (3) is switched 'ON' or switched 'OFF'. The ON/OFF actuation of the switch (3) may be checked before using it in any device. The dome shape on the link (9) allows limited misalignment of the assembly. The switch (3) and link (9) are mounted in the same housing (8). The housing (8) is a molded part. This eliminates the misalignment between two assemblies.
Figure 2 shows the isometric view of the switch operating mechanism. Both Figure 1 and Figure 2 shows microswitch (3) being assembled to the bracket (1). A rod (not shown) actuates the link (9) in the vertical direction shown by the dotted arrow. The link is pushed down by the rod and rotates about a pin (2). The link (9) has a cam profile, which releases the switch (3) when the rod is down. The link (9) is hooked to the bracket (1) by a spring (10). The link comes back to 'up' position when the rod goes up. This operates the switch.
4

The microswitch is isolated from the rod. This prevents damage to the switch even if it is misaligned.
Figure 3 shows the cross sectional view of the isometric view of the switch operating mechanism. This figure shows the microswitch assembly (3) and the switch rod (12) along with the junction box cover (11).
Thus the present invention provides a mechanism to operate a micro switch that requires no adjustment after it is used in any electrical equipment using such microswitches. The performance of the micro-switch is not affected from misalignment of parts used in the assembly. Further, the parts used in the switch mechanism are completely interchangeable. The switch in most of the applications is operated by a linear moving member. This requires accurate positioning of the parts. Any misalignment causes malfunction. All electrical equipment manufacturers using micro switch. All petrol dispensing unit manufacturers using direct contact type switches.
The foregoing description of the invention has been described for purposes of clarity and understanding. It is not intended to limit the invention to the precise form disclosed. Various modifications may be possible within the scope and equivalence of the appended claims.
5

WE CLAIM
1. A switch operating mechanism comprising:
a housing having a cover;
a movable actuator protruding externally to the cover of the housing;
a micro switch adapted within the housing, said micro switch being electrically coupled to the actuator;
a link connected to the actuator within the housing;
whereby said actuator is moved to rotate the link about a hinge point to actuate the ON-OFF operation of the micro switch without requiring any adjustment in the position of said micro switch thereby allowing least misalignment of the micro switch.
2. The switch operating mechanism as claimed in claim 1 wherein the actuator is moved linearly.
3. The switch operating mechanism as claimed in claim 1 wherein the link has a cam profile on the other side of the hinge point.
4. The switch operating mechanism as claimed in claim 1 wherein the micro-switch is switched 'ON' or switched 'OFF', depending on cam position.
5. The switch operating mechanism as claimed in claim 1 wherein the ON/OFF operation of the micro switch ON/OFF can be checked before using said micro switch in any device.
6. The switch operating mechanism as claimed in claim 1 wherein the housing is a molded junction box.
7. The switch operating mechanism as claimed in claim 1 wherein the micro switch is mounted on a bracket.
8. The switch operating mechanism as claimed in claims 6 and 7 wherein the bracket is further mounted on the junction box body.
Dated this 19th day of October, 2006
FOR LARSEN & TOUBRO LIMITED By their Agents
(GIRISH VIJAYANAND SHETH) KRISHNA & SAURASTRI
6

Name : Larsen & Toubro Limited Appl. No. : /MUM/2006

Sheet No. : 1 Total Sheets : 3


10

Figure 1

(GIRISH VIJAYANAND SHETH) KRISHNA & SAURASTRI

Name : Larsen & Toubro Limited Appl. No. : /MUM/2006

Sheet No. : 2 Total Sheets : 3

Figure 2

(GIRISH VIJAYANAND SHETH) KRISHNA & SAURASTRI

Name : Larsen & Toubro Limited Appl. No. : /MUM/2006

Sheet No. : 3 Total Sheets : 3


12
Figure 3