FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
Title of the invention - RESETTING MECHANISM
FOR TRIPPING DEVICE IN CIRCUIT BREAKERS
2. Applicant
(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 INVENTION
The present invention relates to a resetting mechanism for tripping devices. More particularly, the invention relates to a resetting mechanism comprising linking component which has microprocessor or electronic release for the protection having flux-shift trip device enclosed in the same release compartment thereby achieving instantaneous resetting of flux shift device improving tripping operation and increasing the life of circuit breaker.
The mechanism can be used where the resetting of a tripping device such as under voltage release, shunt release and equivalent tripping coils and the like.
BACKGROUND AND PRIOR ART
Switching device e.g electrical circuit breakers are widely complemented by internal accessories such as auxiliary contact, trip alarm contact, shunt release, under-voltage release etc.
Function of electric circuit breaker is to make, carry and break the current. At normal operating conditions when the circuit breaker is carrying current, the operating knob indicates ON position. At abnormal condition due to overload or under-voltage, the circuit breaker gets tripped because of the tripping signal from protective release or remotely tripping through the shunt release or through under-voltage release, operating knob indicates TRIP position. For switching the circuit breaker to ON position after any tripping event, it needs to be manually reset the operating mechanism. RESET position is slightly advanced position than OFF position of the circuit breaker.
Under-voltage release is an important protection device for a circuit breaker. Apart from providing under-voltage protection, it is increasingly used for electrical interlocking. This calls for no momentary touching of contacts during changeover.
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US5805041 describes an electronic trip unit conversion kit includes a flux shifter and reset arrangement to articulate the circuit breaker operating mechanism upon the occurrence of an overcurrent condition to separate the circuit breaker contacts and to reset the flux shifter after the circuit breaker contacts have become separated. The arrangement however does no use any latching means
US5670923 describes a field-installable circuit breaker trip unit conversion kit in the form of a flux shifter unit that interfaces with the circuit breaker operating mechanism is installable without dismantling the circuit breaker components.
US4913503 describes an integrated protection unit is a circuit breaker which includes basic overcurrent protection facility along with selective electrical accessories. A molded plastic accessory access cover secured to the integrated protection unit cover protects the accessory components contained within the integrated protection unit cover from the environment.
US5122771 describes multi-functional accessory actuator-reset unit is arranged within a circuit breaker enclosure to interact between the circuit breaker operating mechanism and the flux-shifter trip actuator mounted within the circuit breaker case and the accessory unit mounted within the circuit breaker cover.
US5014025 describes an integrated protection unit is a circuit breaker which includes basic overcurrent protection facility along with selective electrical accessories.
None of the documents discussed above teaches such integration and arrangement of components for instantaneous resetting of flux shift.
Conventionally actuation for resetting of under-voltage release is taken from drive shaft. When circuit breaker is tried to be switched ON without under-voltage
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release energized, under-voltage actuator trips circuit breaker only when drive shaft moves from OFF position to the ON position resulting into momentary touching of contacts. This momentary touching of contacts leads to carry the short circuit current in the changeover circuit breaker for small duration resulting into erosion of contact buttons and hence reducing life of circuit breaker.
Further these accessories have to take the actuation from the mechanism and hence have a side bias for their operation. This means that the accessories meant to be inserted in the right half of the switching device will not be workable in the left half of the switching device and vice-versa. Hence to mount these accessories one has to go through extensive preparations to avoid confusion.
Thus there is a need to provide for an improved resetting mechanism to avoid momentary touching of contacts thereby increasing the life of circuit breakers.
The present inventors have now found that linking component when integrated and interconnected establishing elctro-mechanical connection between circuit breaker and flux shift tripping plate ensures instantaneous positive resetting of the trip plate without requirement of any special interfacing mechanism.
OBJECTS OF INVENTION
Thus one of the objects of the present invention is to provide a compact, integrated trip resetting mechanism in which resetting lever is mounted on the mechanism itself which acts as dual functional component. During abnormal condition, flux shift plunger actuates the resetter and it trips the circuit breaker by disengaging the trip-plate from latch. After tripping during resetting operation, fork rotates the resetter & resetter brings back the plunger of flux-shift to its latch position.
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Another object of the present invention is to provide trip resetter without use of return spring.
Another object of the invention is to eliminate any special interface mechanism thereby reducing the number of components mounted and hence providing a compact assembly.
Yet another object of the present invention is to provide a resetting lever acting as an intermediate link between flux shift device & the trip plate of the circuit breaker
Another object of the invention is to provide a circuit breaker with an improved trip mechanism that is simple and economical in construction.
SUMMARY OF INVENTION
According to one aspect of the present invention there is provided a resetting mechanism for use in flux shift tripping devices for circuit breakers, said mechanism comprising:
microprocessor or electronic release means in a compartment;
flux shift tripping device operatively connected to said release means in the compartment; and
intermediate link means connecting said flux shift device and trip plate of the circuit breaker;
wherein said means being integrated and interconnected so as to achieve instantaneous resetting of flux shift device improving tripping operation by
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eliminating need of any special interface mechanism thereby providing a simple and compact assembly.
DETAILED DESCRIPTION OF INVENTION
The mechanism of the present invention comprises an intermediate link between flux shift device and the trip plate of the circuit breaker. During every tripping operation this intermediate link ensures positive resetting of flux shift tripping device. The intermediate link being reset lever is mounted on the electrical circuit breaker.
The flux shift device and microprocessor are enclosed in the same release compartment of circuit breaker.
One embodiment of the present invention describes an actuator means being fork of circuit breaker co-operatively linked to resetting lever.
Another embodiment of the present invention describes actuation of the plunger of flux shift trip device. The actuating plunger in turn actuates resetter component/resetting lever, which is the part of the mechanism. The trip-plate is latch with the latch-bracket of the mechanism. This disengages the trip plate from the latch-bracket which interns trips the circuit breaker
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 illustrates side view of the compact trip-resetting mechanism in circuit breaker in OFF position of the present invention.
Figure 2 illustrates side view of the compact trip-resetting mechanism in circuit breaker in ON position of the present invention.
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Figure 3 illustrates Tripping action through the flux shift device and the operative connection of the components of the trip resetting mechanism of the present invention.
Figure 4 illustrates Resetting action through the flux shift device and the operative connection of the components of the trip resetting mechanism of the present invention.
DETAILED DESCRIPTION OF ACCOMPANYING FIGURES
In figure 3 the tripping action through the flux shift trip device and the operative connection of the components of the trip resetting mechanism of the present invention is illustrated. The trip unit comprising flux shift device (1) (shown in figure 2) adapts the trip command, actuating the plunger (1a) of flux shift trip device (1) on sensing an abnormal conditions i.e. fault. The actuation of the plunger (1a) of flux shift trip device (1) in turn actuates resetter component/resetting lever (3), which is the part of the mechanism (4). The trip-plate (5) is latch with the latch-bracket (6) of the mechanism (4). This disengages the trip plate from the latch-bracket which interns trips the circuit breaker as shown in the figure (3).
In figure 4 the resetting action through the flux shift trip device and the operative connection of the components of the trip resetting mechanism of the present invention is illustrated. The resetting action of the flux shift trip device (1) occurs when the fork which is the part of the mechanism is intentionally rotated clockwise, rotates the resetter(3) which interns pushes & resets the plunger(la) of the flux shift device(1). After resetting action , circuit breaker is ready for next closing operation as shown in the figure (1).
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WE CLAIM
1. A resetting mechanism for use in flux shift tripping devices for circuit
breakers, said mechanism comprising:
microprocessor or electronic release means in a compartment;
flux shift tripping device operatively connected to said release means in the compartment; and
intermediate link means connecting said flux shift device and trip plate of the circuit breaker;
wherein said means being integrated and interconnected so as to achieve instantaneous resetting of flux shift device improving tripping operation by eliminating need of any special interface mechanism thereby providing a simple and compact assembly.
2. A resetting mechanism as claimed in claim 1, wherein said intermediate link means comprises resetting lever.
3. A resetting mechanism as claimed in claim 1, wherein the intermediate links means being mounted on the circuit breaker adapted to positively reset the flux shift trip device after every tripping operation.
4. A resetting mechanism as claimed in claims 1 to 3 further comprises
plunger.
5. A resetting mechanism as claimed in claim 4, wherein the plunger being
operatively connected to the resetting lever such that the actuation of the
plunger co-operatively actuates the resetting lever to latch the trip plate
with the trip bracket.
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6. A resetting mechanism as claimed in any preceding claim further comprises tripping latch.
7. A resetting mechanism as claimed in any preceding claims further comprises fork.
8. A resetting mechanism as herein substantially described and illustrated with reference to the accompanying figures.
Dated this the 30,n day of March 2007

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ABSTRACT
TITLE: RESETTING MECHANISM OF TRIPPING DEVICE IN CIRCUIT BREAKERS
The present invention relates to a resetting mechanism for use in flux shift tripping devices for circuit breakers. The mechanism comprises microprocessor or electronic release means in a compartment, flux shift tripping device operatively connected to said release means in the compartment and intermediate link means (3) connecting said flux shift device (1) and trip plate of the circuit breaker.
Figure 3