FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION: SWITCHING DEVICE WITH SPRING LATCHING
MECHANISM
APPLICANT: LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra
INDIA.
PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A) TECHNICAL FIELD
[0001] The present invention generally relates to switching devices and particularly relates to electromechanical switching device. The invention more particularly relates to spring latched switching devices,
B) BACK GROUND OF THE INVENTION
[0002] Mechanical latching, permanent magnet latching and electromagnet latching mechanisms are the common latching mechanisms used in the switching devices. In the existing technique, locking at either ON or OFF positions is done by cam or flapper designs in the mechanical latching. Further in the existing technique, a permanent magnet is used to latch the device at either ON or OFF position. A coil is continuously excited to latch the switching device at either ON or OFF positions.
[0003] Further in the existing techniques, the weight per unit force ratio is higher. In case of permanent magnet latching, de-magnetizing at high currents is also higher. Further in the existing technique, there is high power consumption and coil wear in the electromagnet (Continuous duty or high duty) latching. Further there is a mechanical failure of the latch arrangement in mechanical latching.
[0004] Thus there is a need to for a reliable compression spring based latching mechanism for switching devices which avoids high-power consumption and coil wear out.
[0005] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
C) OBJECT OF THE PRESENT INVENTION

[0006] The primary object of the present invention is to provide a coil based spring latched switching device.
[0007] Another object of the present invention is that to provide a coil based spring latched switching device where at least one of the solenoids is excited in a switching process.
[0008] Yet another object of the present invention is to provide a compression spring mechanism which exhibits an upward force on the moving contact when the switching device is in the switched OFF position.
[0009] Yet another object of the present invention is that the compression spring mechanism exhibits a downward force on the moving contact when the switching device is in the switched ON position.
[0010] Yet another object of the present invention is to provide a compression spring latching mechanism to maintain contact pressure at desired levels in the switching device.
[0011 ] Yet another object of the present invention is to provide a compressing spring latching mechanism in combination with a coil design to overcome the spring opposing force.
[0012] Yet another object of the present invention is to provide a compression spring latching mechanism in combination with a coil design to exert a force on the moving contact.
D) SUMMARY OF THE INVENTION
[0013] The various embodiments of the present invention provide a switching device that includes a moving contact, a fixed contact, a coil, a linking assembly, a double

solenoid actuation mechanism, and a compression spring latching mechanism. The double solenoid actuating system and the compression spring latching mechanism in combine provides a flip locking based electro-magnetic actuation switching device having a low duty coil and a reliable compression spring based latching mechanism.
[0014] According to one embodiment of the present invention, the double solenoid actuation mechanism includes two or more solenoids and the armatures of the two solenoids are coupled to the linking assembly.
[0015] According to one embodiment of the present invention, at least one of the solenoids is excited in a switching process.
[0016] According to one embodiment of the present invention, the device is in switched ON position when an ON coil is excited in the double solenoid actuating system.
[0017] According to one embodiment of the present invention, the device is in switched OFF position when an OFF coil is excited in the double solenoid actuating system.
[0018] According to one embodiment of the present invention, the compression spring mechanism exhibits an upward force on the moving contact when the switching device is in the switched OFF position and exhibits a downward force on the moving contact when the switching device is in the switched ON position.
[0019] According to one embodiment of the present invention, the compression spring latching mechanism maintains a contact pressure at desired levels in the switching device. The coil is designed in such a way that the coil overcomes the spring opposing force.

[0020] According to one embodiment of the present invention, the compression spring latching mechanism exerts a force on the moving contact.
[0021] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0023] FIG. 1 is a prior art diagram illustrating a perspective view of an actuator that is used to switch an electrical device in one of the modes through electromechanical actuation.
[0024] FIG. 2 illustrates a front side perspective view of a coil based spring latched switching device, according to one embodiment of the present invention.
[0025] FIG.3a-3b illustrates the schematic view of an actuation mechanism for the switching devices, according to one embodiment of the present invention.
[0026] FIG. 4 illustrates a front side perspective view of a coil based spring latched switching device in ON position, according to one embodiment of the present invention.
[0027] FIG.5a-5b illustrates the perspective view of the compression spring latching mechanism for the switching devices, according to one embodiment of the present invention.

[0028] Although the specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0029] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0030] The various embodiments of the present invention provide a switching device that includes a moving contact, a fixed contact, a coil, a linking assembly, a double solenoid actuation mechanism, and a compression spring latching mechanism. The double solenoid actuating system and the compression spring latching mechanism in combine provides a flip locking based electro-magnetic actuation switching device having a low duty coil and a reliable compression spring based latching mechanism.
[0031] FIG. 1 illustrates the perspective view of an actuator that is used to switch an electrical device in one of the modes through electromechanical actuation, according to prior art. While with respect to FIG. I the actuator includes a coil wounded around a frame 104 and an armature that transverse through the frame 104. The actuator further includes a plunger 102. The contact assembly includes the fixed contact assembly and the moving contact assembly which are connected to a shaft. Further the linking mechanism connects the actuator and the shaft assembly.
[0032] FIG. 2 illustrates the front side perspective view of a coil based spring latched switching device, according to one embodiment of the present invention. The switching

device includes a double solenoid actuating mechanism 202, a linking assembly 204 and a compression spring latch mechanism 206. The coil based spring latched switching device is a low-duty coil and a reliable compression spring based latching mechanism 206. The low-duty coil used in the switching devices prevents high power consumption, coil wear out and high weight per unit force.
[0033] FIG.3a-3b illustrates a schematic view of an actuation mechanism for the switching devices, according to one embodiment of the present invention. The double solenoid actuation mechanism 202 includes two solenoids. The armatures of the two solenoids are coupled to the linking assembly 204. Only one solenoid is excited at a time during the process of switching the devices.
[0034] The switching devices are switched from either ON to OFF or OFF to ON position. The positions of actuators in the solenoid assembly with OFF and ON positions are shown in Fig 3a and Fig 3b respectively. The device is switched ON when the ON coil 304 is excited and the device is switched OFF when the OFF coil 302 is excited as shown in FIG.3a.
[0035] FIG. 4 illustrates a front side perspective view of a coil based spring latched switching device in the ON position, according to one embodiment of the present invention. FIG.5a-5b illustrates the perspective view of the compression spring latching mechanism for the switching devices, according to one embodiment of the present invention. While with respect to FIG.4 the switching device is in the ON position.
[0036] When the switching device is in the OFF position, the compression spring based latching mechanism 206 exhibits an upward force on the moving contact 502 as shown in FIG 5a. Further when the ON coil 304 is excited, the armature is pulled down along with the linking mechanism 204 which in turn exerts a force on the shaft which moves the shaft in a downward direction,

[0037] The coil 104 is designed in the switching devices in such a way that the coil 104 overcomes the spring opposing force. The net force in turn pushes the shaft downwards. After certain travel, the direction of the force exhibited by the compression spring based latching mechanism 206 is reversed as shown in FIG. 5b and the moving contact 502 travels independent of the armature and the linking assembly 204. A mechanical link plate 402 connects both actuators (plungers) and is a part of linking assembly in the switching device.
[0038] A conduction path in the switching device is achieved through the fixed contact 404, the moving contact 502 and the second fixed contact. The compression spring assembly in the switching device maintains a contact pressure in the switching device at desired levels. The device is switched OFF, when the OFF coil 302 is excited which in turn pulls the armature along with linking mechanism 204 against the compression springs force. The linking mechanism 204 attached to the shaft pulls the moving contact 502 upward along with shaft and after certain travel, the springs are positioned to impart an upward force on the moving contact 502. The moving contact 502 is then shifted to the OFF position.
G) ADVANTAGES OF THE INVENTION
[0039] The advantages of the present invention include a reduction in power consumption during the device operation. Further the use of the low-duty coil in the switching devices prevents the coil wear out and high weight per unit force. Moreover, the chance of mechanical failure of latch arrangement is prevented.
[0040] The present invention provides for an actuation switching device which is of less weight and compact.
[0041] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

[0042] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.

CLAIMS
What is claimed is:
1. A switching device with a spring-latching mechanism comprising:
a moving contact;
a fixed contact;
a coil;
a linking assembly;
a double solenoid actuation mechanism; and
a compression spring latching mechanism;
Wherein the double solenoid actuating system and the compression spring
latching mechanism provides for a flip locking based electro-magnetic actuation
switching device and a reliable compression spring based latching mechanism.
2. The switching device of claim 1, wherein compression spring latching mechanism includes a low-duty coil.
3. The switching device of claim 1, wherein the double solenoid actuation mechanism comprises two or more solenoids.
4. The switching device of claim 3, wherein armatures of the two or more solenoids are coupled to the linking assembly.
5. The switching device of claim 3, wherein at least one of the solenoid is excited in a switching process.
6. The switching device of claim 3, wherein the device is in switched ON position when an ON coil is excited in the double solenoid actuating system.
7. The switching device of claim 3, wherein the device is in switched OFF position when an OFF coil is excited in the double solenoid actuating system,
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3 1 MAR

8. The switching device of claim 1, wherein the compression spring mechanism exhibits an upward force on the moving contact when the switching device is in the switched OFF position.
9. The switching device of claim 1, wherein the compression spring mechanism exhibits a downward force on the moving contact when the switching device is in the switched ON position.
10. The switching device of claim 1, wherein the compression spring latching mechanism maintains a contact pressure at desired levels in the switching device.
11. The switching device of claim 1, wherein the coil is designed in such a way that the coil overcomes the spring opposing force.
Dated this the 30th day of March, 2010

Rakesh Prabhu,
Patent Agent, ALMT Legal,
No.2, Lavelle Road,
Bangalore-560 001,
INDIA
To,
The Controller of Patents,
The Patent office,
At Mumbai
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3 1 MAR 2010