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Title:
TRIPPING MECHANISM PROTECTING FROM RESIDUAL CURRENT AND TRIPPER
Document Type and Number:
WIPO Patent Application WO/2012/083853
Kind Code:
A1
Abstract:
A tripping mechanism protecting from residual current and a tripper (100). The tripping mechanism (102) comprises a tripping bar (20) and a hammer (30). The hammer is engaged with the tripping bar so that the hammer is movable between a normal operating position and a tripping position. The tripping bar has a first engaging portion (23) and a second engaging portion (22A-22C). The first engaging portion interacts with a bar protecting from residual current (40) of a device protecting from residual current so as to operate the tripping bar to activate the hammer to trip. The second engaging portion interacts with at least one of a device protecting from overload and a device protecting from short-circuit so as to operate the tripping bar to activate the hammer to trip. The tripping mechanism is shared by the device protecting from residual current, the device protecting from overload and the device protecting from short-circuit. Therefore, the structures are simplified, and the cost is saved.

Inventors:
SUN, Haitao (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
SHI, Junchang (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
HU, Jiwei (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
FAN, Wenjie (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
Application Number:
CN2011/084367
Publication Date:
June 28, 2012
Filing Date:
December 21, 2011
Export Citation:
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Assignee:
SCHNEIDER ELECTRIC INDUSTRIES SAS (35 rue Joseph Monier, Rueil Malmaison, FR)
SUN, Haitao (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
SHI, Junchang (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
HU, Jiwei (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
FAN, Wenjie (9th Building, No.3000 Longdong RoadPudong, Shanghai 3, 201203, CN)
International Classes:
H01H71/10
Foreign References:
CN102064054A
CN2049020U
CN101710556A
US5686709A
Attorney, Agent or Firm:
LIU, SHEN & ASSOCIATES (A0601, Huibin Building No.8 Beichen Dong Street,Chaoyang District, Beijing 1, 100101, CN)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A tripping mechanism (102) protecting from residual current, comprising: a tripping bar (20) and a hammer (30) interacted with said tripping bar (20) so that said hammer (30) is movable between a normal operating position and a tripping position,

wherein,

said tripping bar (20) has a first engaging portion (23) and a second engaging portion(s) (22A-22C),

a device protecting from residual current is cooperated with said first engaging portion (23) so as to operate said tripping bar (20) to activate said hammer (30) to trip, and

one of a device protecting from overload and a device protecting from short-circuit interacts with said second engaging portion (22A-22C) so as to operate said tripping bar (20) to activate said hammer (30) to trip.

2. The tripping mechanism (102) protecting from residual current as claimed in Claim 1 , wherein,

movement of said hammer (30) between said normal operating position and said tripping position is translational movement.

3. The tripping mechanism (102) protecting from residual current as claimed in Claim 2, wherein,

said tripping bar (20) has an engaged portion (21), and said hammer (30) has an engaging end (31), and the engaged portion (21) of said tripping bar (20) is engaged with the engaging end (31) of said hammer (30) to keep said hammer (30) in said normal operating position.

4. The tripping mechanism (102) protecting from residual current as claimed in Claim 1 , wherein,

said second engaging portion(s) (22A-22C) is (are) in the form of rotational arm which could be cooperated with the device protecting from short-circuit .

5. The tripping mechanism (102) protecting from residual current as claimed in Claim 4, wherein,

the mechanism further comprises a third engaging portion, which is cooperated with the device protecting from overload to realize the tripping of the trip mechanism.

6. The tripping mechanism (102) protecting from residual current as claimed in

Claim 5, wherein,

said third engaging portion is thermal adjusting screws disposed in projections (24A-24C) formed on said tripping bar (20).

7. The tripping mechanism (102) protecting from residual current as claimed in any one of Claims 1-6, wherein,

when said device protecting from residual current is triggered, a bar protecting from residual current (40) of said device protecting from residual current is interacted with said first engaging portion so that the translational movement of said bar protecting from residual current (40) pushes said tripping bar (20) to turn.

8. The tripping mechanism (102) protecting from residual current as claimed in

Claim 7, wherein,

said bar protecting from residual current (40) has a recess portion (42) therein, and the first engaging portion (23) of said tripping bar (20) is constructed as a shape of a platform insertable into said recess portion (42).

9. The tripping mechanism (102) protecting from residual current as claimed in

Claim 7, wherein,

said bar protecting from residual current (40) has a guide limiting portion (411) which is fit with a corresponding guiding portion to guide the translational movement of said bar protecting from residual current (40), and to limit the stroke length of the translational movement of said bar protecting from residual current (40).

10. The tripping mechanism (102) protecting from residual current as claimed in Claim 9, wherein,

said guide limiting portion (411) is a guiding slot (411) formed in said bar protecting from residual current (40), and said corresponding guiding portion is a boss formed on a housing (101) of the tripper, and the boss is inserted into said guiding slot (411).

11. The tripping mechanism (102) protecting from residual current as claimed in Claim 7, wherein,

it further comprises a support (10) which has a guiding passage (11), and said hammer (30) is slidably mounted in said guiding passage (11) and is guided by said guide passage (11).

12. A tripper (100), comprising at least one of an device protecting from overload and a device protecting from short-circuit, and a device protecting from residual current, wherein,

said tripper (100) further comprises the tripping mechanism (102) protecting from residual current as claimed in any one of Claims 1-11, and at least one of the device protecting from overload and the device protecting from short-circuit is fit with one of the second engaging portion(s) (22A-22C) of the tripping bar (20) of said tripping mechanism (102), and said device protecting from residual current is matched with the first engaging portion (23) of said tripping bar (20), so as to trip said tripper (100).

13. The tripper (100) as claimed in Claim 12, wherein,

said tripper (100) is interchangeably assembled on a circuit breaker as an assembly.

Description:
TRIPPING MECHANISM PROTECTING FROM RESIDUAL CURRENT AND

TRIPPER

Technical Field

The present invention relates to a molded case circuit breaker, and particularly relates to a thermal-electromagnetic type tripper for the molded case circuit breaker, which can cooperate with a residual current protector to realize residual current protecting function in additional to overload protection and short circuit protection. Background Art

Molded case circuit breakers have been used widely in medium and low-voltage circuit for distributing electrical energy and protecting lines, power supply and energized equipment.

A molded case circuit breaker generally comprises a tripper performing protecting functions, i.e., overload protection, short circuit protection, time-delayed protection, leakage protection, etc. A circuit breaker as a traditional mechanical structure is ordinarily mainly used to protect against thermal overload and short circuit. A device protecting from thermal overload is commonly composed of a bimetallic strip and a current circuit. When the temperature exceeds a certain threshold, the bimetallic strip will be deformed to push a tripping mechanism to trip. A device protecting from short-circuit commonly consists of a coil and an electromagnet which will act to push the tripping mechanism to trip when short-circuit current exceeds a certain threshold.

Furthermore, besides above protecting functions, the molded case circuit breaker is generally further provided with a device protecting from residual current. The device protecting from residual current is capable of identifying a fault leakage current in a circuit, thereby ensuring the security of people and systems.

Due to the trend of miniaturization and cost reduction of molded case circuit breakers, nowadays the device protecting from residual current is ordinarily cooperated with a thermo-magnetic tripper to cut off a fault leakage current in a circuit. And after clearing of fault, the mechanism of the thermo-magnetic tripper should reset the tripper and the circuit breaker body only after the device protecting from residual current is reset.

In the circuit breaker of the prior art, although it has been realized that the device protecting from residual current is cooperated with the thermo-magnetic tripping mechanism, it is necessary to provide a large tripping force provided by the device protecting from residual current, and the design margin is small. Thereby, in the events that a short-circuit fault occurs, the mechanism is contaminated, and the like, the tripper could not be tripped or tripped incorrectly, and the reliability is reduced.

Disclosure of the Invention

Therefore, there is always a need to improve existing thermal electromagnetic trippers and mechanisms protecting from residual current.

In view of the above mentioned prior art, according to the present invention, a novel tripping mechanism protecting from residual current is provided, comprising a tripping bar and a hammer. Said trip interacts with said tripping bar so as to move the tripping bar between a normal operating position and a tripping position. Said tripping bar has a first engaging portion and a second engaging portion. A bar protecting from residual current of a device protecting from residual current interacts with said first engaging portion so that said tripping bar acts and then motivates said hammer to trip. And at least one of device protecting from overload and a device protecting from short-circuit interacts with said second engaging portion so that said tripping bar acts and then motivates said hammer to trip.

Said second engaging portion is a rotational arm to be cooperated with the device protecting from short-circuit. And said tripping bar further comprises a third engaging portion which is fit with the device protecting from overload to facilitate the tripping bar to act in the event of overload.

With the above structure, a single tripping protecting mechanism is shared by the device protecting from residual current, the device protecting from overload, the device protecting from short-circuit, etc. Thus, the structure is simplified and the cost is reduced. And since the behavior of the mechanism to realize residual current protection by the tripper is same as that of short circuit protection and overload protection, that is, the hammer pushes the circuit breaker to be tripped. Thus, the tripping architecture between the tripper and the circuit breaker body is simplified, and the indication design of fault currents is also simplified.

Preferably, the movement of said hammer between said normal operating position and the tripping position is a translational movement. In addition, said bar protecting from residual current acts on the engaging portion of said bar protecting from residual current so that said tripping bar turns in a first direction, and at least one of said device protecting from overload and said device protecting from short-circuit acts on said second engaging portion, so that said tripping bar turns in said first direction. Preferably, said tripping bar has an engaged portion and said hammer has an engaging end. Said tripping bar is biased so that the engaged portion thereof engages with the engaging end of the hammer to remain said hammer at said normal operating position.

With the above structures, the hammer is released by translational sliding, ensuring that the circuit breaker mechanism is pushed to be tripped reliably and the tripping procedure is simple to ensure the action reliable and stabilized. The bar protecting from residual current can be cooperated with a residual current protector to act, to push the tripping mechanism to be tripped when a leakage current fault occurs, thereby cutting off fault current. To realize tripping, the tripping force to be provided by the protector protecting from residual current can be reduced greatly, thus the design margin is increased greatly and the reliability of products is improved, especially the reliability of the function of protecting from residual current is improved after short-circuit fault occurs(the mechanism is contaminated heavily).

Preferably, when said device protecting from residual current is triggered, said bar protecting from residual current moves translationally along the length direction thereof to push the tripping bar

With this structure, comparing with the prior art structure in which the bar protecting from residual current rotates to push the tripping bar, the space required for the motion of bar protecting from residual current can be reduced, and the reliability of the motion of the bar protecting from residual current can be improved, and the trigger force of device protecting from residual current can be reduced.

Preferably, said bar protecting from residual current is provided with a guide limiting portion which interacts with the corresponding portion provided in a base of the tripping mechanism or a housing of the circuit breaker so as to perform a guiding function for the bar protecting from residual current during the movement of said bar protecting from residual current and limit the travel of said bar protecting from residual current. Preferably, said guide limiting portion is a guiding slot formed in one side of said bar protecting from residual current, and said corresponding portion is a guiding boss provided on the base of said tripping mechanism or the housing of the circuit breaker, and the guiding boss is inserted into said guiding slot.

With this structure, the stability of the motion of the bar protecting from residual current can be ensured by a simple structure.

Preferably, the engaging portion of said bar protecting from residual current is a platform portion arranged on one side of the tripping bar, which is inserted into a recess portion formed in said bar protecting from residual current, so that said recess portion abuts against and pushes the platform portion of said tripping bar during the translational motion of said bar protecting from residual current.

With this structure, when the device protecting from residual current is not reset, since the platform portion of the tripping bar is inserted into the recess portion of the bar protecting from residual current, the turning of the tripping bar in the resetting direction is stopped. That is, the resetting of the tripping mechanism and the tripper body can only by realized until the device protecting from residual current is reset, thus improving the safety of the equipment.

Said tripping mechanism protecting from residual current further comprises a support which has a guiding passage. Said hammer is slidably mounted in said guiding passage, and is guided by said guiding passage.

By providing the support, the hammer can be located more accurately, and the action of the hammer is guided by the support, and the reliability of the operation of the hammer is improved.

Preferably, said tripping mechanism protecting from residual current is arranged on the housing of the tripper to constitute an assembly.

With this structure, the tripper can be assembled with the circuit breaker as a whole, resulting in interchangeability (existing between the circuit breaker and the tripper; between the tripper and the residual current protector), facilitating for industrialized manufacture and meeting the requirements of different customer. By employing the structure of the tripping mechanism, the time of manufacture and assembly of the circuit breaker is also reduced effectively, more facilitating for storage and management of the manufacture.

According to the present invention, a tripper comprising the above tripping mechanism is also provided.

Brief Description of the drawings

Other aspects, features and advantages will become easy to understand and can be determined readily with respect to the following description when taken in conjunction with the accompanying drawings.

Fig.1 is a perspective view illustrating a tripper according to one embodiment of the present invention;

Fig.2 is a perspective view illustrating the tripper showed in Fig.1 from another view;

Fig.3 is a perspective view illustrating a tripping bar of the tripping protecting mechanism for the tripper showed in Fig.1 ;

Fig.4 is a perspective view illustrating a hammer of the tripping protecting mechanism for the tripper showed in Fig.1 ;

Fig.5 is a perspective view illustrating a bar protecting from residual current of the tripping protecting mechanism for the tripper showed in Fig.l;

Fig.6 is a perspective view illustrating a support of the tripping protecting mechanism for the tripper showed in Fig.1 ;

Fig.7 is a schematic view illustrating the assembly of the hammer of Fig.4 and the support of Fig.6;

Fig.8 is a schematic view illustrating the assembly of the tripping bar of Fig.3 and the hammer of Fig.4;

Fig.9 is a schematic view illustrating the assembly of the tripping bar of Fig.3 and the bar protecting from residual current of Fig.5; and,

Fig.10 is schematic views for explaining residual current protection. Fig.1 OA illustrates the state before the mechanism protecting from residual current is triggered, that is, the state before the tripping mechanism is tripped. And Fig.1 OB illustrates the state after the mechanism protecting from residual current is triggered, that is, the state after the tripping mechanism is tripped.

The drawings are intended to describe exemplary embodiments of the present disclosure, and should not be explained to limit the scope of the present disclosure. Unless explicitly indicated, the drawings should not be considered to be drawn in proportion.

Best Mode for Carrying Out the Invention

During describing the embodiments showed in the drawings, specific terms are used for reasons of clarity. However, the disclosure of this patent specification is not intended to be limited to such selected specific terms. And it should be understood that each specific element includes all technical equivalents with similar operations and similar effects. In the following descriptions, the terms "include", "comprise" and the like should be understood to be open-ended, the intent of which is that there may be other unnamed elements or members which may be easily conceived by those skilled in the art according to the instructions of the present invention, except the elements or members indicated.

Although exemplary embodiments are described with some technical limitations with reference to the accompanying drawings, the description is not intended to limit the scope of the present invention. And all components or elements described in the exemplary embodiments of this disclosure are not indispensable to the present invention. Preferred embodiments are described in detail below with reference to the accompanying drawings. Fig.l and Fig.2 illustrate a tripper 100 according to the preferred embodiments. As well known in prior art, the tripper 100 mainly comprises a main housing 101, an assembly part (not shown) assembling the tripper 100 with a circuit breaker, protecting devices (not shown) housed in the main housing 101, and a tripping mechanism 102 substantially mounted on the top portion of the main housing 101, etc. The protecting devices include an overload protecting device, a short-circuit protecting device and a residual current protecting device, which are triggered in the case of overload, short circuit, fault leakage current and the like, thereby tripping the tripping mechanism. As these protecting devices are same as the prior art protecting devices, and are not critical to the present invention. Therefore, those skilled in the art can realize them with reference to the structures in the prior art, and herein detailed description may be omitted.

The tripping mechanism 102 according to the preferred embodiments of the present invention is described in detail below with reference to the accompanying drawings, especially from Fig.3 to Fig.10. The tripping mechanism 102 is designed as an assembly, detachably mounted on the top of the main housing 101 of the tipper 100 and is common among a plurality of different types of trippers. Then the mounted tripper 100 can be assembled with the circuit breaker as a whole.

As shown in Fig.l and Fig.2, the tripping mechanism 102 substantially comprises a support 10, a tripping bar 20, a hammer 30 and a bar protecting from residual current 40. The support 10 is mounted on the main housing 101 of the tripper 100 to house the tripping bar 20, the hammer 30 and the bar protecting from residual current 40 of the tripping mechanism 102. The tripping bar 20 can be pivotable by a shaft passing there through. Two opposite ends of said shaft are arranged on a side plate 50, respectively. Of course, the shaft can also be integrated with the tripping bar 20, and pivotally mounted on the side plate 50 by the two ends of the shaft (i.e., two ends of the tripping bar 20).

In addition, the tripping bar 20 is biased in a predetermined direction by means of a restoring spring (not shown). The spring may be a torsion spring, and one end of torsion arm thereof is caught in the tripping bar 20 and the other end is caught in a corresponding slot (not shown), so as to bias the tripping bar 20 in the predetermined direction (clockwise direction, in the present invention). Of course, other forms of springs or elastic elements may also be adopted to realize like functions, which are all included within the scope of the present invention.

As shown in Fig.3, the tripping bar 20 is generally an elongate rod, and one side (that is horizontal side in Fig.3) of the outer periphery thereof is provided with a engaged portion 21 so as to engage with the hammer 30 which will be described below. In addition, another side (that is downside in Fig.3) of the outer periphery of the tripping bar 20 is provided with a plurality of rotational arms 22A-22C which is jointed with trigger elements of a three-phase short-circuit protecting device, respectively, after mounted on the tripper 100. Three projections 24A-24C are respectively disposed on a top side of Fig.3 of the tripping bar 20, corresponding to three phases. These projections 24A-24C is provided with holes 25A-25C, and thermal adjusting screws (not shown) are threaded into these holes. After assembly, these thermal adjusting screws are respectively fit with trigger elements of the overload protecting device. The length of the thermal adjusting screws protruding from the holes 25A-25C may be adjusted, thus the stroke length of the whole mechanism protecting from overload and the gap between the thermal adjusting screws and the trigger element of the device protecting from overload can be adjusted. In addition, an engaging portion 23 to engage with the bar protecting from residual current is disposed at a different position on one side of the tripping bar 20 which is substantially the same side of the rotational arms 22A-22C, which is to engage with a bar protecting from residual current 40 that will be described below and is formed a substantially shape of platform.

Now with reference to Fig.4 and Fig.8, the hammer 30 is a substantially elongate rod, and one end thereof has a engaging end 31 , and the other end is formed as a substantially disc-shaped execution portion 33 which pushes a locking device of a circuit breaker mechanism and then cuts off fault current. In addition, a rib 32 can be disposed on the main body of the hammer to improve the strength of the whole hammer 30. As shown in Fig.8, after assembly, the hammer 30 is positioned over the tripping bar 20, and the engaging end 31 of the hammer 30 is caught with the engaged portion 21 of the tripping bar 20. As shown in the figures, in preferred embodiments of the present invention, the engaging end 31 of the hammer 30 is a hook, and the engaged portion 21 of the tripping bar 20 is a step. However, it is understood for those skilled in the art that any appropriate shape may be adopted so long as both of them can realize releasable engagement without deviating from the scope of the present invention.

Now with reference to Fig.6 and Fig.7, the hammer 30 is mounted in a guiding passage 11 of the support 10 which is mounted on the base of the tripping mechanism 102. And the guiding passage 11 of the support 10 has a channel (not shown), so as to be matched with the rib 32 of the hammer 30, to ensure correct installation of the hammer 30, and to guide the movement of the hammer 30 during the hammer 30 moves. Of course, the present invention is not limited to this guiding structure, and any guiding structure may be adopted to realize the guiding function for the hammer 30. A bias spring (not shown) is disposed between the hammer 30 and the support 10 so as to bias the hammer 30 in a direction shown by the arrow A in Fig.1 OA and Fig.10B.

Now with reference to Fig.5 and Fig.9, the bar protecting from residual current 40 is an elongate bar, which slides in a predetermined direction when the device protecting from residual current is triggered. The bar protecting from residual current 40 is guided to move by means of a corresponding portion (not shown) of the housing 101 of the tripper 100. Particularly, a protruding portion 41 is formed on one side of the bar protecting from residual current 40, in which a guiding slot 411 is formed. After assembly, a guiding boss (not shown) as the guiding portion of the housing 101 of the tripper is inserted into the guiding slot 411, so that the bar protecting from residual current 40 moves only in the length direction (along the length direction of the bar protecting from residual current 40 in Fig.5) of the guiding slot 411 back and forth, and the stroke length of the movement is defined by the length of the guiding slot 411 in the length direction. Of course, other forms of guiding and limiting structures may be adopted. For example, the guiding boss is formed on the bar protecting from residual current 40, and the guiding slot is formed in the main housing 101 of the tripper, which all falls within the protection scope of the present invention.

In addition, a recess portion 42 is formed in the residual current bar 40 at a corresponding position in the length direction thereof. The recess portion 42 is sized so that it can be engaged with engaging portion23 of the tripping bar 20. Particular, after assembly, the engaging portion 23 of the tripping bar 20 is inserted into the recess portion 42 so as to push the tripping bar 20 to turn through the engagement between the engaging portion 23 and the recess portion 42 following the movement of the bar protecting from residual current 40. However, other structures may also be adopted for the engagement of the tripping bar 20 and the bar protecting from residual current 40. For example, a boss is formed on the bar protecting from residual current, which may abut against the residual-current-protective-bar engaging portion of the tripping bar, thereby pushing the tripping bar to turn. Alternatively, other engaging means may be adopted such as dowels, tenons or the like. Therefore, all structures capable of realizing the above functions should fall within the protection scope of the present invention.

With reference to Fig.1 OA and Fig.10B below, the operating principles of the trip mechanism of the present invention is described.

Fig.10 illustrates the state before the tripping mechanism is triggered. As shown in Fig.1 OA, in this state, under the action of the restoring spring of the tripping bar 20, the engagement between the engaging end 31 of the hammer 30 and the engaged portion 21 of the tripping bar 20 is held, and the hammer 30 is kept in place. And the engaging portion 23 is inserted into the recess portion 42 of the bar protecting from residual current 40. The tripper 100 is in a normal operating status.

When a fault leakage current occurs, a residual current protecting device (not shown) is triggered, so that the bar protecting from residual current 40 moves along the direction shown by arrow A of Fig.1 OA, and then the recess portion 42 of the bar protecting from residual current 40 pushes the engaging portion 23 of the tripping bar 20, so that the tripping bar 20 turns around a shaft in a counter-clockwise direction of Fig.10. With the turning of the tripping bar 20, the engaged portion 21 of the tripping bar 20 and the engaging portion 31 of the hammer 30 are released. Thus, the holding effect of the tripping bar 20 on the hammer 30 is lost, and the hammer 30 moves translationally along the direction shown by arrow A of Fig.1 OA under the action of the bias spring (not shown) and under the guiding of the guiding mechanism of the support 10. The hammer 30 pushes the locking device of the circuit breaker mechanism and then cuts off the fault current. Fig.10B illustrates the state at this moment.

If the fault is not cleared, since the tripping bar 20 is pushed to a position shown in Fig.10B by the recess portion 42 of the bar protecting from residual current 40 at this moment and the bar protecting from residual current 40 is unable to be reset and thereby hinders the turning of the tripping bar 20 along the clockwise direction before clearance of the fault leakage current, despite pushing the hammer 30 in a direction opposite to the direction shown by arrow A, the engaged portion 21 of the tripping bar 20 is unable to engage with the engaging end 31 of the hammer 30. Therefore, the hammer 30 is unable to be reset. After clearance of the fault, through pushing the hammer 30 along the direction opposite to the direction shown by arrow A of Fig.1 OA, the whole tripping mechanism is reset, and at this moment, as the bar protecting from residual current 40 does not hinder the turning of the tripping bar 20 anymore, and the tripping bar 20 turns along the clockwise direction of Fig.10 under the action of the restoring spring so that the engaged portion 21 of the tripping bar 20 is engaged with the engaging end 31 of the hammer 30.

The tripping mechanism according to preferred embodiments of the present invention has been described above with reference to the residual current protecting device. Meanwhile, as mentioned above, said tripping bar 20 is further provided with a plurality of rotational arms 22A-22C which can be fit with the short-circuit protecting device, and the thermal adjusting screw disposed on the tripping bar 20 is fit with the overload protecting device. Therefore, when one of the short-circuit protecting device and the short-circuit protecting device and the like is triggered due to occurrence of overload current, short-circuit current, and the like, the triggered portion of the protecting device pushes the rotational arm 22 of the tripping bar 20 or the thermal adjusting screw of the tripping bar 20, thus resulting in the turning of the tripping bar 20, and the whole tripping mechanism is tripped. Herein the operating mode of the tripping mechanism will not be repeat anymore which is similar to that described above with reference to the residual current protecting device.

For certain embodiments of the present invention which has been described in such way, it is obvious that they may vary in many ways. And within the scope of the present disclosure and the claims, elements and/or features of different exemplary embodiments may be combined and/or replaced with each other. For example, in detailed embodiments, the tripping bar 20 is provided with three rotational arms 22A-22C and three thermal adjusting screws 25A-25C to correspond to three phases. However, the number is not limited, and one or more rotational arms or thermal adjusting screws may also be adopted according to the service condition. The engaged portion of the tripping bar may be a protruding form, and engages with the engaging portion of the hammer in the recess form, and vice versa. The hammer is provided with the rib 32 to improve the strength of the hammer 30, and meanwhile the rib 32 is also used as the guided portion of the hammer so as to be engaged with a corresponding portion of the support to realize sliding guiding for the hammer 30. Certainly, the rib for improving strength and the guiding portion may be formed separately, and other various guiding structures commonly used in the art may also be adopted. The specific positions of the lap engaging portion, the rotational arms and the like of the tripping bar 20 may be changed according to the overall design of the tripper, without being limited to that shown in the drawings. These modifications should not be considered to depart from the scope of the present invention, and the intention of all such improvements is to be included within the scope of the present invention as defined by the appended claims only.