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:
TRIPPING MECHANISM FOR ELECTRICAL PROTECTION APPARATUS
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 and protection
devices and particularly to the protection devices which employ spring biased and interface assisted mechanism. The present invention more particularly relates to an arrangement in the electrical protection apparatus which aids in tripping by improving force balance configuration.
B) BACKGROUND OF THE INVENTION
[0002] A circuit breaker is an automatically-operated electrical switch
designed to protect an electrical circuit from damage caused by overload or short circuit. The circuit breakers detect a fault condition and interrupts continuity to immediately discontinue electrical flow. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.
[0003] Isolation of electrical circuits is necessary to protect downstream
equipments or apparatus against high currents/voltage arising during short circuit or overload currents. The conventional devices used to accomplish electrical isolation during fault have evolved from early fuse elements with obvious need of replacement of fuse to reenergize the circuit. Although, invention of electrical protection devices such as circuit breakers and relays overcame this problem, a need exists to minimize the response time of these protection devices at abnormal situations.
[0004] In the existing technique, a method of operating a circuit breaker
includes the step of rotating an interface plate from a first position to a second position. An opening latch shaft is rotated from a third position to a fourth position with the interface plate. A set of contacts is opened when the opening latch shaft is in

the fourth position. The interface pJate is further rotated from the second position to a fifth position. A closing latch shaft is rotated from a sixth position to a seventh position when the interface plate rotates from the second position to the fifth position while keeping the opening shaft in forth position. The energy stored in compression springs is discharged when the closing latch shaft rotates from the sixth position to the seventh position.
[0005] Thus there exists a need to provide an improved electrical protection
device to achieve quickness and reliability in operation. Also there exists the need for a simple design to avoid intricate complex structure which may further entangle troubleshooting.
[0006] The abovementioned shortcomings, disadvantages and problems are
addressed herein and which will be understood by reading and studying the following specification.
C) OBJECTS OF THE INVENTION
[0007] The primary object of the present invention is to provide an
accelerated interface lever assist mechanism for electrical protection devices.
[0008] Another object of the present invention is to provide an accelerated
interface lever assist mechanism which is simple and compact.
[0009] Yet another object of the present invention is to provide an
accelerated interface lever assist mechanism with increased reliability.
[0010] Yet another object of the present invention is to provide an
accelerated interface lever assist mechanism which achieves fast tripping.

[0011] Yet another object of the present invention is to provide an
accelerated interface lever assist mechanism which isolates faulted or overloaded feeders to avoid damages to the device.
[0012] 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.
D) SUMMARY OF THE INVENTION
[0013] The various embodiments of the present invention provide an
accelerated interface lever assist mechanism. According to one embodiment of the present invention, the circuit breaker consists of mechanism housing along with the terminals and interface lever. Further the interface lever is attached to at least one of the terminal by solid means such as welding.
[0014] The accelerated interface lever assist mechanism consists of housing,
a pivot assembly, a compensation system, at least two sliders, a trip indicator, a main spring, an interface lever, terminals, a reaction point and an action point. The mechanism generates a force during operation which acts along the pivot assembly through the point of reaction. The force is further transferred to the force action spring, trip indicator and the slider. The force in turn moves the spring, trip indicator and slider.
[0015] The slider is provided with a plurality of recesses through which
interface lever acts. During actuation acted through the pivot assembly, the trip indicator moves and attains an intermediate position. The interface lever acts along with the pivot and during normal operation the interface lever connects with contact attached to terminal. This interface lever does work in control contact.

[0016] The interface lever along with the main spring provides a force
balance in the device, thereby creating an equilibrium condition. During this equilibrium condition, trip indicator takes the position wherein the slider and main spring are in contact. During tripping condition, the slider moves by certain distance and main spring force starts decreasing as it is ready to undergo for force direction reversal. The interface lever ensures a certain degree of over travel required for establishing current through control contact.
[0017] When the slider moves in the direction opposite to its normal position,
the degree of over travel decreases. At an intermediate position, when mechanism spring is at about force reversal condition slider movement is adjusted in such a way that the slider pushes interface lever. The interface lever is pushed by motion of slider under influence of actuation coming from pivot assembly. Further, the interface lever flips over to other direction, thereby accelerating a motion of the slider and thereby tripping mechanism.
[0018] During tripping action, the interface lever and main spring acts
simultaneously to achieve a tripped condition which is another equilibrium condition. In the tripped condition, the slider and interface lever and the trip indicator occupies the tripped condition. During reset operation by a secondary means, the reset button slider is moved in an opposite direction. The trip indicator, the main spring, and the interface lever operationally connected to the slider also moves with the slider and attain another equilibrium condition. In case of reset operation, a force is induced on the slider motion which brings back the interface lever to equilibrium condition.
E) BRIEF DESCRIPTION OF THE DRAWINGS:
[0019] 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:

[0020] FIG. I illustrates a cross-sectionai front view of the accelerated
interface lever assist mechanism according to one embodiment of the present invention.
[0021] FIG. 2 illustrates a cross-sectional rear view of the accelerated
interface lever assist mechanism according to one embodiment of the present invention.
[0022] FIG. 3 shows the slider with recesses through which the interface
lever acts according to one embodiment of the present invention.
[0023] FIG. 4 shows other sectional view of the slider with a plurality of
recesses through which interface lever acts according to one embodiment of the present invention.
[0024] FIG. 5 illustrates the slider position and interface lever position in a
tripped condition according to one embodiment of the present invention.
[0025] FIG. 6 shows shows other side view of the accelerated interface lever
assist mechanism showing an equilibrium state of main spring, trip indicator according to one embodiment of the present invention.
[0026] FIG. 7 shows the interface lever as a standalone component according
fa one embodiment of the present invention.
[0027] Although 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
[0028] In the following detailed description, 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.
[0029] The various embodiments of the present invention provide an
accelerated interface lever assist mechanism for electrical protection device such as thermal overload relay. According to one embodiment of the present invention, the thermal overload relay consists of mechanism housing 100 along with the terminals 107 and an interface lever 106. Further the interface lever 106 is attached to at least one of the terminal 107 by a solid means such as welding.
[0030] The Thermal overload relay primarily consists of a mechanism
housing 100, pivot assembly 101, a compensation system 102, at least two sliders 103a and 103b, a trip indicator 104, a main spring 105, an interface lever 106, terminals 107, a reaction point 108 and an action point 109. The mechanism generates a force during operation which acts along the pivot assembly 101 through the reaction point 108. The force is further transferred to the force action spring, trip indicator 104 and the slider 103. The force in turn moves the spring, trip indicator and slider.
[0031] FIG. 1 illustrates a cross sectional front view of the interface lever
assists mechanism according to one embodiment of the present invention. With respect to FIG. 1, the interface lever assist mechanism constitutes of a mechanism housing (100) along with the terminals (107) and interface lever (106). Further the

interface lever (106) is attached to at least one of the terminal (107) by solid means such as welding.
[0032] FIG. 2 illustrates a cross sectional rear view of interface lever assist
mechanism according to one embodiment of the present invention. With respect to FIG. 2, the assembly consists of mechanism housing (100), a pivot assembly (101). a compensation system (102), at least two sliders (103-A and 103-B), a trip indicator (104), a main spring (105), an interface lever (106), terminals (107), a reaction point (108) and action point (109). From pivot assembly (101) through reaction point (108) the slider reaction point, trip indicator (104) and main spring (105) acts along with this force action spring and trip indicator (104) thus the slider (103) moves.
[0033] FIG. 3 illustrates the interface lever provided with a plurality of
recesses according to one embodiment of the present invention. The slider (103) is a given a small recesses through which interface lever acts in FIG 02. During actuation of the pivot assembly (101), the trip indicator (104) moves and takes intermediate position as shown in FIG. 2. The interface lever (106) acts along the pivot (101) and during normal operation interface lever (106) connects with contact attached to terminal (107). This interface lever (106) works under control contact.
[0034] The force balance situation is created with the help of the interface
lever (106) along with main mechanism spring (105) and creates an equilibrium condition. During this equilibrium condition, the trip indicator (104) takes the position as shown in FIG.01. During tripping condition slider (103) moves by certain distance and the main spring force starts decreasing as it is ready to undergo for force direction reversal. Interface lever (106) ensures certain degree of over travel required for establishing current through control contact.
[0035] When the slider (103) moves in the direction shown in the FIG.3, the
over travel starts decreasing and at one intermediate position when mechanism spring

(105) is at about force reversal condition slider (103) movement is adjusted in such a way that the slider (103) pushes interface lever. Since interface lever (106) is pushed by motion of slider under influence of actuation coming from pivot assembly (101) interface lever (106) flips over to other direction and thereby accelerating motion of slider and thereby tripping mechanism. During tripping action, interface lever (106) and main spring (105) acts thereby achieving tripped condition which is another equilibrium condition B.
[0036] FIG. 4 shows other sectional view of the slider (103) which is a given
a small recesses through which interface lever (106) acts according to one embodiment of the present invention.
[0037] FIG. 5 shows a new slider (103) position and interface lever (106)
position with respect to accelerated interface lever assist mechanism according to one embodiment of the present invention. The trip indicator (104) also occupies the tripped condition as shown in the figure 5.
[0038] FIG. 6 illustrates a perspective view of interface lever asset
mechanism showing another equilibrium state of the main spring (105), trip indicator (104) and the slider 103 according to one embodiment of the present invention. During the reset operation by a secondary means, the reset button slider is moved in an opposite direction, for instance rotated at an angle of 180 degree with respect to the first equilibrium position. The trip indicator (104), the main spring (105), the interface lever (106) operationally connected to slider 103 also moves with the slider and attains the equilibrium condition A.
[0039] FIG. 7 shows the interface lever (106) as a standalone component
with respect to the accelerated interface lever assist mechanism according to one embodiment of the present invention. The slider is provided with a plurality of small recesses. In case of reset operation, the main spring exerts a force on the slider which

sets the slider in motion. The movement of the slider 103 brings back the interface lever (106) to equilibrium 'A' condition.
G) ADVANTAGES OF THE INVENTION
[0040] The various embodiments of the present invention provide an
interface lever assist mechanism which is simple and compact and achieves fast tripping with increased reliability.The present invention provides a mechanism where the housing consists along with the terminals and interface lever. Further the interface lever is attached to at least one of the terminal by solid means such as welding. The present invention provides a flexible arrangement which helps in fast tripping.
[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 tripping mechanism for electrical protection apparatus, the mechanism comprising: a housing; a pivot assembly; a compensation system; at least one slider; a slider reaction point; a trip indicator; a main spring; and an interface lever;
wherein the at least two sliders are provided with a plurality of recesses through with the interface lever acts to accelerate the mechanism thereby reducing the tripping time.
2. The mechanism according to claim 1, further comprising at least one of a slider reaction point and a slider action point.
3. The mechanism according to claim 1, wherein the actuation of the pivot assembly exerts a force on the main spring and trip indicator thereby inducing a movement on the slider.
4. The mechanism according to claim 1, wherein an actuation of the pivot assembly moves the trip indicator so as to attain an intermediate position.
5. The mechanism according to claim 1, wherein the interface lever acts along the pivot assembly and connects with a contact attached to a terminal during normal operation.

6. The mechanism according to claim 1, wherein the interface lever and the main spring creates a force balance to provide an equilibrium condition.
7. The mechanism according to claim 1, wherein the slider moves in the direction opposite to a normal position during a tripping condition.
8. The mechanism according to claim 1, wherein the interface lever is pushed by motion of slider due to actuation of the pivot assembly at an intermediate position.
9. The mechanism according to claim 1, wherein the interface lever flips over to a direction thereby accelerating a motion of the slider for tripping.

10. The mechanism according to claim 1, wherein the interface lever and main spring acts simultaneously to achieve a tripped condition.
11. The mechanism according to claim 1, wherein the trip indicator, the main spring, and the interface lever are operationally connected to the slider such that a movement of the slider provides for an equilibrium position.
12. The mechanism according to claim 1, further comprising a reset button to induce a force on the slider to bring back the interface lever to an equilibrium condition.