JP2002075157A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker for enhancing insulation properties and enhancing short-circuit interruption capacity. SOLUTION: The circuit breaker is provided with a movable leaf, whose one end is fixed to a body 2 and whose other end taken as a free end, is fitted with a movable contact, a fixed contact which comes into contact with and separated from the movable contact, a return spring for urging the movable leaf in a direction of opening of the contact, a handle 20 supported turnably on a frame 17 fixed to the body 2, a driving member 28 disposed freely movably in the vertical directions between a disconnection stopping rib 29 installed protrusively in the body 2 and the frame 17 and pressing the movable leaf in the direction, where the contact is pressed downward by a pressing member 23 in order to be closed, when the handle 20 is subjected to on-operation in a state with the pressing member 23 being engaged with a latching member 24, and a return spring 31 for urging the driving member 28 in direction of being separated from the rib 29 for the propose of forming a gap between the driving member 28 and the rib 29, when the contact is opened for separation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker for operating a handle to open and close a contact portion comprising a fixed contact and a movable contact, and forcibly opening the contact portion in response to an excessive current such as a short-circuit current. It is about.

[0002]

2. Description of the Related Art A conventional circuit breaker of this type is disclosed in Japanese Patent Application Laid-Open No. 2000-40458.
In the circuit breaker described in the above publication, FIGS.
As shown in FIG.
A fixed terminal plate 10 having a fixed contact 9 is electrically connected to the power supply terminal 4, and the load terminal 5 is formed of a long conductive plate having elasticity. The movable spring plate 11 to which the bimetal 13 is fixed is electrically connected to the portion. The fixed contact 9 constitutes a contact portion together with a movable contact 12 provided on the movable spring plate 11, and the movable contact 12 provided on the other end of the movable spring plate 11 is fixed in accordance with the operation of the opening / closing / tripping mechanism 6. Approaching and leaving. A braided wire 16 is connected to the other end of the bimetal 13, and is connected to the load-side terminal 5 via the braided wire 16. Therefore,
When the contact portion is closed, an electric path through which a current flows is formed in a route of the power supply side terminal 4-fixed contact 9-movable contact 12-bimetal 13-load side terminal 5. In addition, the movable spring plate 11
A compression spring 27 is arranged between the body 1 and the body 1. The compression spring 27 urges the movable spring plate 11 in a direction in which the movable contact 12 moves away from the fixed contact 9.

The opening / closing / tripping mechanism 6 has a handle 20 rotatably supported in the body 1, and an operating portion 20 a of the handle 20 is moved from the handle insertion hole 3 a on the upper surface of the body 1 to the body 1. It is housed in the housing 1 so as to protrude from the upper surface. A frame 17 is attached to the bottom of the body 1, and a pin 21 is passed through a shaft hole 17 c formed at an upper end of the frame 17 and a hole 20 b of the handle 20.
A handle 20 is rotatably attached to the frame 17. A driving member 28 is disposed in a guide groove 30 formed between a retaining rib 29 erected from the bottom surface of the container 1 and the frame 17 so as to be vertically movable. The drive member 28 moves up and down in response to.

When the driving member 28 is pushed downward in FIG. 9 in response to the turning operation of the handle 20, the movable spring plate 1
The portion between the movable contact 12 and the compression spring 27 in FIG. 1 is pressed downward in the figure by the drive member 28, and the movable contact 12 and the fixed contact 9 come into contact. At this time, the compression spring 2
The spring biasing force 7 acts so as to press the movable spring plate 11 to which the movable contact 12 is fixed to the fixed contact 9 side with the driving member 28 as a fulcrum, thereby increasing the contact pressure between the two contacts 9 and 12. Work on. When the contact is opened, the compression spring 2
The spring biasing force 7 acts to move the movable contact 12 away from the fixed contact 9.

[0005]

In the circuit breaker having the above structure, if an abnormal current such as a short-circuit current flows in the electric circuit when the contact is closed, the contact is forcibly opened by the switching / tripping mechanism 6. However, when the contact portion is forcibly opened, an arc is generated, and the vicinity of the contact portion is exposed to the arc and carbonized. Since the driving member 28 is vertically movable in the guide groove 30 formed between the frame 17 and the retaining rib 29, the driving member 28 and the retaining rib 29 are moved by an arc generated at the time of forced opening. If the driving member 28 is carbonized and is in contact with the retaining rib 29 at the time of opening, the movable contact 12 and the fixed contact 9 are moved along the route of the fixed contact 9, the retaining rib 29, the driving member 28, and the movable spring plate 11. May be short-circuited.

When the contact portion is opened, the movable spring plate 11 is opened.
The movable spring plate 11 is urged in a direction away from the fixed contact 9 by its own spring force and the spring force of the compression spring 27. However, when an excessive short-circuit current flows at the time of closing, the contact portion is welded. There is a problem that the short-circuit breaking current cannot be increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a circuit breaker having improved short-circuit breaking capacity while improving insulation.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a movable contact having one end fixed to a body and having a movable contact at the other end which is a free end. ,
A fixed contact that comes into contact with or separates from the movable contact; a first return spring that urges the movable contact in a direction in which the movable contact moves away from the fixed contact; and a handle rotatably supported by a support member fixed to the body. A pressing member having an intermediate portion in the longitudinal direction connected to the handle via a link mechanism, and an engaging portion for engaging one end of the pressing member, the pressing member and the engaging portion being detachably engaged. A latch member movably attached to the body so as to be urged in a direction in which the pressing member and the engaging portion engage with each other, and a pressing member and the engaging portion when an abnormal current such as an overcurrent or a short-circuit current flows. A tripping member for moving the latch member in a direction to release the engagement state, and a groove into which the other end of the movable contact is inserted, between the movable contact and the other end of the pressing member. Movably arranged, the engagement portion of the latch member is engaged with the pressing member In this state, the driving member is pressed by the other end of the pressing member when the handle is turned on to press the movable contact in a direction in which the movable contact comes into contact with the fixed contact. And a second return for urging the driving member away from the retaining portion such that a gap is formed between the driving member and the retaining portion when the contact is separated. Characterized by comprising a spring, when an abnormal current flows, the tripping member releases the engagement state of the pressing member and the latch member, and when the force for pushing the driving member by the other end of the pressing member is lost, Since the other end of the movable contact is inserted into the groove of the driving member, the spring force of the second return spring acts on the movable contact via the driving member, and the first and second return springs are moved. The movable contact is pressed in the opening direction by the spring force. Since that can enhance the force tripping movable contact from the fixed contact, it is possible to increase the short-circuit breaking capacity. In addition, the second return spring presses the driving member away from the retaining portion to form a gap between the driving member and the retaining portion. There is no danger of short-circuiting in the path, and the insulation can be improved.

According to a second aspect of the present invention, in the first aspect of the present invention, the second return spring is disposed at a position closer to the retaining portion than the center of gravity of the driving member. Is arranged closer to the retaining portion with respect to the position of the center of gravity of the driving member, the biasing force of the second return spring acts in the direction to move the driving member away from the retaining portion, and the driving member can be surely moved away from the retaining portion. it can.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the housing is provided with a storage recess in which the second return spring is disposed. Since the second return spring is disposed in the place, the positioning of the second return spring can be facilitated, the installation work can be facilitated, and the second return spring can be prevented from coming off.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the driving member is provided with a positioning locking portion for locking with the second return spring. By locking the stop with the second return spring, the second
Can be prevented from coming off from the drive member, and the biasing force of the second return spring can reliably urge the drive member away from the retaining portion.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the biasing direction of the second return spring is inclined to the side opposite to the retaining portion with respect to the moving direction of the driving member. The biasing force of the second return spring acts in a direction to move the driving member away from the retaining portion, and the driving member can be surely moved away from the retaining portion.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The circuit breaker of the present embodiment includes a power supply terminal 4, a load terminal 5, and an opening / closing / tripping mechanism 6 inside the housing 1, as shown in FIG. For convenience of explanation, the upper surface of the container shown in FIG. 1 is referred to as an upper surface (front), the lower surface is referred to as a lower surface (rear surface), the right surface is referred to as a right surface, and the left surface is referred to as a left surface.

The body 1 is a body 2 made of a synthetic resin molded product.
And a cover 3 and are connected using a connecting member (not shown) such as a screw. The circuit breaker of the present embodiment is for two poles, and a pair of power supply terminals 4 and 4 and load terminals 5 and 5 are disposed on both left and right sides of the body 2 respectively. A handle 20 to be described later is provided substantially at the center of the upper surface of the cover 3.
A handle insertion hole 3a for inserting the operation portion 20a is provided, and terminal screw operation holes 3b are provided on both left and right sides.
In addition, at the portions facing the power supply side terminal 4 and the load side terminal 5 on both the left and right side surfaces of the housing 1, an electric wire insertion hole 8 is formed by cutting out a joint surface between the body 2 and the cover 3.

The terminal plate of each power supply terminal 4 has a fixed terminal plate 1
0 is formed integrally with each fixed terminal plate 1.
The fixed contact 9 is fixed upward at the other end of the reference numeral 0.
Each fixed terminal plate 10 is fixed to the body 2 using pins 26. A pair of movable spring plates (movable contacts) 11 made of a long conductive plate having elasticity are arranged on the upper surface of the body 2. The movable spring plate 11 is bent obliquely upward from the middle part, and its free end has a corresponding fixed contact 9.
A movable contact 12 constituting a contact portion is fixed downward, and the movable contact 12 comes into contact with and separates from the fixed contact 9 in accordance with the operation of the opening / closing / tripping mechanism 6.

One end of the bimetal 13 is superimposed on one end of the movable spring plate 11 which serves as a fixed end, and a fixing screw 14 is passed through one end of the bimetal 13, one end of the movable spring plate 11 and the bottom surface of the body 2. The movable spring plate 11 and the bimetal 13 are fixed to the body 2 by being screwed and fastened to the nut 15 arranged on the back side of the bottom surface 2. Movable spring plate 1
A concave portion 2a is provided in a portion of the body 2 facing the intermediate portion of the first spring 1. A return spring (first return spring) 27 formed of a compression coil spring is disposed in the concave portion 2a. The spring is urged in the opening direction by the return spring 27. Further, the bimetal 13 is bent in a substantially inverted L-shape from the fixed portion, and its tip portion is inclined and extended upward. The other end of the bimetal 13 has a braided wire 1
The other end of the braided wire 16 is electrically connected to the load-side terminal 5. Here, the electric circuit of the circuit breaker includes the load-side terminal 5, the braided wire 16, the bimetal 13, the movable spring plate 11, the fixed terminal plate 10, and the power supply-side terminal 4.

The movable spring plates 11, 1 on the upper surface of the body 2
A frame (supporting member) 17 for supporting the opening / closing / tripping mechanism 6 is disposed in a portion between the two. The frame 17 includes a fixing piece 17a fixed to the upper surface of the body 2;
It has a pair of side pieces 17b projecting upward from the body 2 from both sides of the fixing piece 17a, and a fixing screw 18 penetrating through the fixing piece 17a and the bottom surface of the body 2 is disposed on the back side of the bottom surface of the body 2. The frame 17 is fixed to the body 2 by being screwed and fastened to the nut 19 thus set. A shaft hole 17c is provided at the upper end of each of the side pieces 17b, 17b, and the pin 21 is passed through the shaft hole 17c and the hole 20b of the handle 20 so that the operating portion 20 of the handle 20 is moved.
The handle 20 is rotatably supported by the frame 17 so that a protrudes from the handle insertion hole 3a of the cover 3 to the outside.

An intermediate portion in the longitudinal direction of a pressing member 23 is connected to the handle 20 via a link 22.
The pressing member 23 is driven according to the rotation operation of the handle 20. The pressing member 23 has side pieces 23b, 23b protruding downward from both side edges of the strip-shaped central piece 23a. The handle 20 has a hole 20b.
And the link insertion hole 20c on the side opposite to the operation portion 20a.
Are provided, and a link 22 is provided in the link insertion hole 20c.
Is inserted at one end. The link 22 is U-shaped,
The other end is inserted through a hole provided in the side piece 23b of the pressing member 23, and is slidably guided by a slit 17d provided in the frame 17.

Also, both side pieces 17b, 17 of the frame 17 are provided.
A shaft hole 17e for receiving a pin 25 for pivotally supporting the latch member 24 is provided at a lower end of the shaft b. The latch member 24 has an engaging projection (engaging portion) 24a that engages with an engaging piece 23c provided on a central piece 23a of the pressing member 23,
By inserting a pin 25 into a shaft hole 17e of the frame 17 and a hole 24b provided at the lower end of the latch member 24, the engagement projection 24a is rotatably attached to and disengaged from the engagement piece 23c. The engaging projection 24a is urged by an urging spring (not shown) so as to approach the engaging piece 23c. In addition, gap adjusting screws 24c, 24c are provided at upper ends of the latch members 24 at portions opposed to the pair of bimetals 13, 13, respectively. Here, when an abnormal current flows in the above-described electric circuit, the bimetal 13 as the tripping member is self-heated, and the gap adjusting screw 24c
And the latch member 24 is rotated against the spring force of the biasing spring, so that the engagement piece 23c and the engagement protrusion 24 are pressed.
The engagement state with the contact point a is released, and the contact portion is forcibly opened. The current value of the abnormal current at which the trip mechanism operates can be set by adjusting the amount of protrusion of the gap adjusting screw 24c.

By the way, at a portion between the two contact portions on the upper surface of the body 2, a retaining rib 29 serving as a retaining portion is protruded, and a guide groove formed between the frame 17 and the retaining rib 29. A driving member 28 is disposed inside 30 so as to be vertically movable. The driving member 28 includes a pair of movable spring plates 11 and 1.
On the lower sides of the driving member 28, grooves 28b, 28b into which the side edges of the distal end portions of the movable spring plates 11, 11 are respectively inserted are provided. A concave portion (housing concave portion) 2b is formed in a portion of the body 2 facing the driving member 28, and a return spring (second return spring) 31 formed of a compression coil spring is provided in the concave portion 2b. The drive member 28 is biased upward by a return spring 31. Further, on the upper surface of the driving member 28, a pressing portion 23 provided on a central piece 23a of the pressing member 23 is provided.
A pressing member receiving portion 28a is provided at a portion facing d.

As described above, the side edge of the movable spring plate 11 is inserted into the groove 28b of the drive member 28, and the spring force of the movable spring plate 11 itself and the spring force of the return spring 27 act on the drive member 28. I do. The drive member 28 is pressed directly upward by the spring force of the return spring 31, and the drive member 28 is urged upward by the spring force of the movable spring plate 11 and the return springs 27 and 31. When the handle 20 is turned from the off position to the on position in a state where the engagement piece 23c of the pressing member 23 and the engagement protrusion 24a of the latch member 24 are engaged, the handle 20 is connected to the handle 20 via the link 22. The pressed pressing member 23 is pressed down, and the pressing member 2
The driving member 28 is moved by the pressing portion 23d of the movable spring plate 1
1 and the return springs 27 and 31 are pressed downward against the spring force. At this time, the movable spring plate 11 is pressed and bent in the closing direction by the driving member 28, and the movable contact 12 and the fixed contact 9 come into contact. Since the driving member 28 presses the portion of the movable spring plate 11 between the movable contact 12 and the compression spring 27 downward, the spring biasing force of the compression spring 27 is applied to the movable contact 12 with the driving member 28 as a fulcrum. It acts so as to press the portion of the fixed movable spring plate 11 to the fixed contact 9 side, and works to increase the contact pressure between the two contacts 9 and 12. Also,
The end of the link 22 on the handle 20 side crosses a line connecting the pin 21 and the end of the link 22 on the pressing member 23 side to reach an inverted state. The spring force of the return spring 27 is
1. Link 22 via driving member 28 and pressing member 23
, The handle 20 is rotationally urged in the direction opposite to the off direction, and locked to the edge of the handle insertion hole 3a.

The operation of the circuit breaker will be described below.
1 and 2 show the ON state. When the handle 20 is rotated clockwise about the pin 21 in a state where the engaging piece 23c of the pressing member 23 is engaged with the engaging protrusion 24a of the latch member 24, the pressing member 23 side of the link 22 follows the slit 17d. To move downward, the pressing member 23
The pressing member 23d pushes down the driving member 28, and the movable spring plate 11 is pushed down against the spring force of the return springs 27 and 31, so that the movable contact 12 and the fixed contact 9 are pressed.
Is in contact with At this time, the handle side of the link 22 moves to the reverse position beyond the line connecting the pin 21 and the pressing member 23 side of the link 22, and the handle 20 is moved to the handle insertion hole 3.
a, thereby opening / closing / tripping mechanism 6,
The latch member 24, the driving member 28, and the movable spring plate 11 are turned on by the return springs 27 and 31 in a uniform manner.
When the electric circuit is closed, the terminals 4 and 5 are electrically connected to each other to supply power to the load.

FIGS. 5 and 6 show the off state. When the handle 20 is rotated counterclockwise from the ON state, the handle 20 side of the link 22 moves from the inverted position to a non-inverted position beyond the line connecting the pin 21 and the pressing member 23 side of the link 22. At this time, the pressing member 23 side of the link 22 moves upward along the slit 17d, and the pressing member 23 moves upward, so that there is no force to push the drive member 28 downward, and the spring force of the return springs 27, 31 As a result, the movable spring plate 11 is pushed up in the opening direction, and the movable contact 12 and the fixed contact 9 are opened. Further, the handle 2 is changed from the state shown in FIG. 5 to the state shown in FIG.
This is done by manipulating 0.

On the other hand, when an abnormal current such as a short-circuit current flows in the electric circuit in the ON state, the bimetal 13 generates heat and bends.
The gap adjusting screw 24c is formed by the bimetal 13 as shown in FIG.
Pressed to the middle left. At this time, the latch member 24 rotates counterclockwise in FIG.
Is disengaged from the engagement piece 23c of the latch member 24 and the engagement protrusion 24a of the latch member 24, so that there is no force to press the drive member 28 downward by the pressing portion 23d of the pressing member 23,
Since the movable spring plate 11 is pushed upward by the spring force of the return springs 27 and 31, the pressing portion 2 of the pressing member 23
3d is pushed upward by the driving member 28, and the pressing member 23 rotates counterclockwise around the pressing member 23 side of the link 22.

As described above, when an abnormal current such as a short-circuit current flows in the electric circuit, and the switching / tripping mechanism 6 trips the contact portion, the movable spring plate 11 has a spring force of the movable spring plate 11 itself and two return springs. Since the spring is pressed in the opening direction by the spring force of the movable contact 12 and the fixed contact 9, the force for detaching the contact portion is increased as compared with the conventional circuit breaker.
Can be prevented from being fixed, and the short-circuit breaking capacity can be increased.

Further, since the return spring 31 is disposed at a position closer to the retaining rib 29 with respect to the position of the center of gravity of the driving member 28, the driving member 28 is moved away from the retaining rib 29 when the contact portion is opened. And a gap is formed between the driving member 28 and the retaining rib 29. Therefore, even if the drive member 28 and the retaining rib 29 around the contact portion are carbonized by being exposed to the arc generated at the time of forced opening, a gap is formed between the driving member 28 and the retaining rib 29. Since the fixed contact 9 and the movable contact 12 are not short-circuited via the driving member 28 and the retaining rib 29, the insulation property can be improved. Further, since the return spring 31 is disposed in the concave portion 2b provided in the body 2, the return spring 31 can be easily positioned, and the work of disposing the return spring 31 is facilitated. 31 can be prevented from coming off the drive member 28.

In the above embodiment, the return spring 3
The return spring 31 is disposed on the body 2 so that the biasing direction of the driving member 1 is substantially the same as the moving direction of the driving member 28. However, as shown in FIGS. The return spring 31 is disposed in the recess 2b obliquely with respect to, so that the biasing direction of the return spring 31 is opposite to the retaining rib 29 with respect to the moving direction of the driving member 28. The spring may be inclined, and the spring force of the return spring 31 acts in a direction to move the driving member 28 away from the retaining rib 29, so that a gap can be reliably formed between the driving member 28 and the retaining rib 29.

The driving member 2 facing the return spring 31
8, a positioning protrusion (locking portion) 28 c for locking with the return spring 31 may be formed.
By locking the locking projection 28c with the locking projection 28c, the return spring 31 can be prevented from coming off the drive member 28, and the spring force of the return spring 31 can be reliably applied to the drive member 28.

In this embodiment, the return springs 27 and 31 made of compression coil springs are used as the first and second return springs, but the first and second return springs are limited to the compression coil springs. Needless to say, a spring member such as a leaf spring may be used instead of the above.

[0030]

As described above, according to the first aspect of the present invention, a movable contact having one end fixed to a body and having a movable contact at the other end serving as a free end comes into contact with and separates from the movable contact. A fixed contact, a first return spring for urging the movable contact in a direction in which the movable contact is separated from the fixed contact, a handle rotatably supported by a support member fixed to the body, and an intermediate portion in a longitudinal direction. A pressing member connected to the handle via a link mechanism, and an engaging portion that engages with one end of the pressing member. A latch member attached to the body and urged in a direction in which the pressing member and the engaging portion engage with each other, and when an abnormal current such as an overcurrent or a short-circuit current flows, the engaging state between the pressing member and the engaging portion is changed. A tripping member for moving the latch member in the releasing direction, and the other end of the movable contact It has a groove to be inserted, is movably arranged between the movable contact and the other end of the pressing member, and is turned on by operating the handle in a state where the engaging portion of the latch member is engaged with the pressing member. Between the driving member pressed by the other end of the pressing member to press the movable contact in a direction in which the movable contact comes into contact with the fixed contact, and between the supporting member protruding from the body to prevent the driving member from coming off And a second return spring for urging the driving member away from the retaining portion so as to form a gap between the driving member and the retaining portion when the contact is separated. The abnormal current flows, the tripping member releases the engagement state of the pressing member and the latch member, and the abnormal current flows, the tripping member releases the engaging state of the pressing member and the latch member, and the pressing member No longer pushes the drive member by the other end of the If, since the groove portion of the drive member the other end side of the movable contactor is inserted,
Since the spring force of the second return spring acts on the movable contact via the driving member and the movable contact is pressed in the opening direction by the spring force of the first and second return springs, the movable contact is fixed. The force for detaching from the contact can be increased, and the short-circuit breaking capacity can be increased. In addition, the second return spring presses the driving member away from the retaining portion and forms a gap between the driving member and the retaining portion.
There is no danger of short-circuiting in the path of the driving member, the retaining portion, and the fixed contact, and there is an effect that the insulation property is improved.

According to a second aspect of the present invention, in the first aspect of the present invention, the second return spring is disposed at a position closer to the retaining portion than the position of the center of gravity of the driving member. Is arranged closer to the retaining portion with respect to the position of the center of gravity of the driving member, the biasing force of the second return spring acts in the direction to move the driving member away from the retaining portion, and the driving member can be surely moved away from the retaining portion. There is an effect that can be.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a storage recess in which the second return spring is disposed is provided in the body, and the second return spring is provided in the storage recess. Since the second return spring is disposed in the place, the positioning of the second return spring can be facilitated, the arrangement work can be facilitated, and the second return spring can be prevented from coming off.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the driving member is provided with a positioning locking portion for locking with the second return spring. By locking the stop with the second return spring, the second return spring can be prevented from coming off the drive member, and the biasing force of the second return spring reliably moves the drive member away from the stopper. There is an effect that it can be energized.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the biasing direction of the second return spring is inclined to the side opposite to the retaining portion with respect to the moving direction of the driving member. In addition, the urging force of the second return spring acts in a direction to move the driving member away from the retaining portion, and there is an effect that the driving member can be surely moved away from the retaining portion.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 3, showing an ON state of a circuit breaker of the present embodiment.

FIG. 2 is a sectional view taken along the line BB of FIG. 3, showing the ON state of the above.

FIG. 3 is a top view of the same.

FIG. 4 is an exploded perspective view in which the part is omitted.

FIG. 5 is a cross-sectional view taken along the line AA of FIG.

6 is a cross-sectional view taken along the line BB of FIG.

FIG. 7 shows the ON state of another circuit breaker of the above, and FIG.
FIG. 4 is a sectional view taken along line AA of FIG.

FIG. 8 is a cross-sectional view taken along line AA of FIG.

FIG. 9 is a sectional view of a conventional circuit breaker.

FIG. 10 is an exploded perspective view of the same.

[Explanation of symbols]

 2 Body 17 Frame 20 Handle 23 Pressing Member 24 Latch Member 28 Driving Member 29 Prevention Rib 31 Return Spring

Claims (5)

[Claims] 1. A movable contact having one end fixed to a body and having a movable contact at the other end serving as a free end, a fixed contact that comes into contact with and separates from the movable contact, and a direction in which the movable contact separates from the fixed contact. A first return spring for urging the movable contact, a handle rotatably supported by a support member fixed to the body, and an intermediate portion in the longitudinal direction connected to the handle via a link mechanism. A pressing member, and an engaging portion that engages with one end of the pressing member. The pressing member and the engaging portion are movably attached to the body so that the pressing member and the engaging portion are detachably engaged. A latch member biased in a direction in which the latch member is engaged, and a tripping member that moves the latch member in a direction to release the engaged state between the pressing member and the engaging portion when an abnormal current such as an overcurrent or a short-circuit current flows. And a groove into which the other end of the movable contact is inserted. The movable contact is pressed by the other end of the pressing member when the handle is turned on while the engaging portion of the latch member is engaged with the pressing member and is movably disposed between the other end of the pressing member. A driving member for pressing the movable contact in a direction in which the movable contact comes into contact with the fixed contact, a retaining portion projecting from the body for holding the driving member and holding the driving member between the supporting member, and a contact opening. A circuit breaker, comprising: a second return spring for urging the driving member away from the retaining portion so that a gap is formed between the driving member and the retaining portion when separated. 2. The circuit breaker according to claim 1, wherein the second return spring is arranged at a position closer to the retaining portion than the position of the center of gravity of the driving member. 3. The circuit breaker according to claim 1, wherein a housing recess in which the second return spring is disposed is provided in the body. 4. A circuit breaker according to claim 1, wherein said drive member is provided with a positioning locking portion for locking with said second return spring. 5. The circuit breaker according to claim 1, wherein a biasing direction of the second return spring is inclined to a side opposite to the retaining portion with respect to a moving direction of the driving member.