JPH089881Y2 - circuit protector - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] The inventors of the present application have already applied for a push button type circuit protector in Japanese Patent Application No. 62-191048.
This is a circuit protector with a just reset type trip-free mechanism that combines a power supply opening / closing function with a similar external shape with a tubular fuse holder with a push type handle instead of an OFF lever type and an overcurrent protection function.

However, in Japanese Patent Application No. 62-191048, the push button is divided into an ON-side operation unit and an OFF-side operation unit at the approximate center of the button surface, even though it is a push-button type, and if you want to perform an ON operation, press the OFF operation unit to turn it ON. Without doing so, there was a problem that the operation as intended by the operator could not be performed. Therefore, the inventors of the present invention intend to provide a complete push button type circuit protector in which the push button operation section is not divided into the ON side and the OFF side, and ON / OFF can be repeated each time it is pressed no matter where the operation section is pressed. To do.

[Constitution of device]

(1) Opening / closing with respect to the fixed contact together with the movable contact in accordance with the swing of the first suspension part that has at least the movable contact and the first suspension part substantially integrally and has a restricted movement trajectory. Operating link bearing A blocking spring which is directly or indirectly suspended between the link bearing and the case and always urges the link bearing in the contact opening direction. One end of the link bearing is the first suspension of the link bearing. A link spring, which is rotatably supported by the main part, and the other end of which is rotatably supported by a second suspension part provided on a handle, which will be described later, comprises a main body part and a projection part protruding from the main body part. , The main body has a contact surface, and both ends of the contact surface have an ON-side contact portion and OF
The F-side abutting portion is provided, and the protrusion is formed on the opposite side of the abutting surface of the main body, and the tip of the protrusion has an inclined surface from the ON-side abutting portion of the abutting surface. A holding claw that extends substantially parallel to the abutting surface toward the OFF-side abutting part, a second suspension part provided near the holding claw, a latch with a stopper, and a suspension between the latch and the link spring, and always holds A latch spring for bending and urging the latch and the link spring in a direction in which the claw and the holding claw engaging projection of the case, which will be described later, are disengaged, a latch accommodating concave portion and a mechanism accommodating portion, and the latch accommodating concave portion and the mechanism accommodating portion are provided. In between, a holding claw engaging projection having an inclined surface corresponding to the holding claw of the latch and a holding claw sliding guide surface,
Similarly, a case having a stopper engaging protrusion corresponding to the stopper of the latch is formed, and the inclined surface of the holding claw and the inclined surface of the retaining claw engaging projection form a pair to form a first engaging portion, and The stopper and the stopper engaging projection form a pair to form a second engaging portion, and the second suspension portion is close to the mechanism housing portion side when the first engaging portion is engaged, When the engaging portion of the second engaging portion is engaged, it is close to the latch storage recess side, and the first suspending portion is swung via the link spring according to the position of each of the second suspending portions. The contact is in the closed position when the suspension is in the position where the first engaging part is engaged, and the contact is in the open position when the second engaging part is in the engaged position, and In the state where either the first engaging portion or the second engaging portion is engaged, or in the intermediate transition process thereof,
The second suspension portion includes a first suspension portion and a latch contact surface.
The holding claw engaging protrusion and the stopper engaging protrusion are disposed and formed in the case at positions where the ON side abutting end and the OFF side abutting end are constrained within a range within a virtual triangle. In the state where the engaging portion of is engaged, the inclined surface of the retaining claw of the latch and the inclined surface of the retaining claw engaging protrusion of the case are contact points with respect to the line segment connecting the first suspension portion and the second suspension portion. Is inclined at an angle such that the engagement is deepened by the reaction force of the contact pressure, and the link bearing and the first suspension portion are substantially integrally combined with each other via the engaging means, The link receiving of the engaging means and the engagement of the first suspension portion are configured to be disengaged by the integrally combined overload detecting means, and the operation surface is provided on the case outer surface of the recess of the latch accommodating portion of the case. The ON operation contact part and the OFF contact part corresponding to the ON side contact end and the OFF side contact part of the latch, respectively. Scan and the stopper operation button that has been subjected to means, it is constructed by a spring for urging the operation buttons to constantly casing outward.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 are views for explaining the internal mechanism in an assembled state, in which the case is half removed, FIG. 1 shows a stable state of “OFF”, and FIG. 2 shows “ON”. Fig. 3 shows a stable state in which the latch is manually biased in the ON direction, but the contact is opened by releasing the engagement due to the action of the overcurrent detection element, a so-called trip-free state. .
FIG. 4 is an exploded perspective view of main mechanical components.

In the figure, reference numeral 1 denotes a case, which is made of an insulating material, and in this example, is divided into two at the cross-sectional portions shown in FIGS.

Inside the case, there is a mechanism storage 64 and a latch storage recess 65.
A stopper engaging projection 20 and a holding claw engaging projection 18 having an inclined surface 67 and a guide surface 66 at the positions shown in the drawing.

A terminal plate 14 extends a terminal portion 58 to the outside of the case, and a fixed contact 16 is fixed inside the case, and is fixedly mounted on the case 1.

Reference numeral 13 is a connection conductor, which similarly extends the terminal portion 55 to the outside of the case, and the end portion on the side opposite to the terminal portion 55 is bent into an L shape and fixedly mounted at a predetermined position of the case mechanism housing portion as shown in the figure. It
The L-shaped end has a notch 53 and engaging grooves 51, 5 at the end.
2. Suspension grooves 49 and 50 are formed respectively.

Reference numeral 9 denotes a link bearing, in which the claws 35 and 36 provided at the base end are engaged with the engaging grooves 51 and 52 of the connection conductor 13 and penetrate through the notch 53 of the connection conductor 13 as well. Extends to the right for a long time.

The engagement between the claws 35 and 36 and the engagement grooves 51 and 52 is maintained by the blocking spring 12 which will be described later, and the link bearing 9 is biased rightward in the drawing with respect to the connection conductor 13.

The other end of the link bearing 9 is bent and has a mounting end 37,
At the mounting end, an insulating bushing 10 having a high expansion side surface 42 and a low expansion side surface 41, into which a protrusion 40 of the bimetal 11 to which the movable contact 15 is fixed is inserted in a hole 39, is fitted, and the bimetal 11 is movable. Supports the end on the contact 15 side.

At the base end of the bimetal 11, the width 44 is the connecting conductor.
The notch 53 of the 13 is inserted, and the fixing surface 43 is formed by the link receiving claws 35, 3
It is loosely held between 6 and the protrusion 68 of the case 1, and the stop surface 69 is supported by the base to prevent the movement to the left in the figure.

The bimetal 11 has the claws 35 and 36 of the link bearing 9 and the engaging grooves 51 and 52.
The movable contact 15 fixed to the bimetal and the fixed contact 16 fixed to the terminal plate 14 are opened / closed by swinging substantially integrally with the swing of the engaging base end portion as a fulcrum.

The fixing surface 43 of the bimetal 11 is fixed to the end portion 48 of the lead wire 17, the other end portion 47 of the lead wire 17 is fixed to the connecting conductor 13, and the terminal plate 14 is fixed between the terminal portions 58 and 55. The contact point 16, the movable contact point 15, the bimetal 11, the lead wire 17, and the connection conductor 13 are electrically connected.

Further, in the middle part of the link bearing 9, the suspension part of the breaking spring 12 is provided.
34 and a link engaging part that uses part of the inner edge of the rectangular hole
31, link spring stop surfaces 32, 33 are formed.

12 is a breaking spring, and one end 45 is on the suspension portion 34 of the link bearing 9,
One end 61 is suspended in the suspension grooves 49, 50 of the connecting conductor 13 so that the link bearing 9 is always on the right side of the drawing with respect to the connecting conductor 13 and the claws 35, 36 of the link bearing 9 engage with the connecting conductor 13. The engaging portion with the grooves 51, 52 is used as a fulcrum to urge it to rotate counterclockwise in the drawing.

Reference numeral 4 denotes a latch, which contacts the tip of the main body having an abutting surface including the ON-side abutting portion 24 and the OFF-side abutting portion 25, and the surface of the holder portion opposite to the abutting surface. A holding claw 70 having an inclined surface 27 extending in the direction from the ON side contact portion to the OFF side contact portion substantially parallel to the surface, a second suspension portion 26 near the holding claw 70, and a projection having a stopper 23 have.

The above-mentioned latch 4 has a contact surface exposed outward in the latch accommodating recess 65 of the case 1, and the holding claw 70, the second suspension 26,
The stopper 23 is stored toward the mechanism storage portion 64 side of the case 1.

Here, the holding claw 70 and the holding claw engaging protrusion 18 are paired to form a first engaging portion, and the stopper 23 and the stopper engaging protrusion 20 are paired to form a second engaging portion. Both the first engaging portion and the second engaging portion are engaged in a direction that prevents the latch 4 from falling out of the case from the latch housing recess 65.

Further, as shown in FIG. 2, when the first engaging portion is engaged, the second engaging portion is disengaged, and the abutting surfaces including the abutting portions 24 and 25 of the latch 4 in the latch accommodating recess 65 are relatively moved. Has moved to the bottom of the figure.

Further, as shown in FIG. 1, the first engagement is disengaged when the second engaging portion is engaged, and the tip of the holding claw 70 is operated on the sliding guide surface 66 of the holding claw engaging projection 18. In the latch accommodating recess 65, the contact surface including the contact portions 24 and 25 of the latch 4 moves relatively upward in the drawing.

The latch 4 and the link bearing 9 are connected by a link spring 6 and a link 8. The U-shaped link spring 6 is suspended between the second suspension portion 26 of the latch 4 and the first suspension portion 29 of the link 8, and the V-shaped groove 28 of the link 8 is the link engagement portion of the link bearing 9. The joint 31 is engaged with the V-shaped bottom. The link 8 also has a bimetal contact surface 30 that is fitted in the rectangular hole of the link bearing 9 and projects toward the bimetal 11 side.

Further, a latch spring 7 is interposed between the link spring 6 and the latch 4, and the latch spring 7 is shown in the drawing such that the link spring 6 is clockwise with respect to the latch 4 about the second suspension portion 26. It is biased to rotate.

In FIGS. 1 and 2, the link spring 6 is always biased clockwise by the latch spring 7 around the second suspension portion 26, and the first suspension portion 29 is linked with the link. Since it is pressed against the stop surfaces 32 and 33 of the bearing 9,
The suspension part 29 of FIG. 2 is always located below the line segment connecting the second suspension part 26 and the engaging part 31, and the breaking spring 12
The rotational urging force of the link bearing 9 by the force acts in the direction in which the second suspension portion 26 and the engagement portion 31 are brought closer to each other, so that the first suspension portion
29 is located on the stop surfaces 32, 33 of the link bearing 9 and does not come off, and the first suspension portion 29 behaves as if it were formed integrally with the link bearing 9.

Now, the latch holding claw 70 and the case holding claw engaging protrusion 18
In the state where the first engaging portion of the above is engaged, that is, the state of FIG. 2, the second suspension portion 26 is engaged with the stopper 23 of the latch and the second engaging portion of the stopper engaging protrusion 20 of the case. The position relationship is arranged so that it is closer to the mechanism side than when it is in the state shown in FIG. 1, that is, in the state shown in FIG. 1, and the first suspension portion 29 inserts the link bearing 9 into the pawl of the link bearing 9 via the link spring 6. 35,3
6 is pressed against the urging force of the breaking spring 12 so as to rotate in the clockwise direction in the drawing with the engaging portions of the grooves 51 and 52 of the connecting conductor 13 as the fulcrum. At this time, the contacts come into contact with each other, and due to the reaction force thereof, the inclined surface 27 of the holding claw 70 of the latch 4 and the inclined surface 67 of the holding claw engaging protrusion 18 of the case 1 form the second suspension portion 26 and the first suspension portion. With respect to the line segment connecting 29, the first engagement is inclined at an angle that makes it deeper and the second engagement is continued while maintaining the engagement.
Continue to maintain the contact closed state shown in the figure. Further, the latch 4 has an abutting surface including the abutting portions 24 and 25, and the latch housing recess 6 of the case 1.
Maintains a position relatively below 5.

Next, in the state where the stopper 23 of the latch 4 and the second engagement of the stopper engagement protrusion 20 of the case 1 are combined, that is, in the state of FIG. 1, the second suspension portion 26 is As compared with the state shown in FIG. 2 in which the engaging portions are connected, the link bearing 9 is located farther than the mechanical portion. Therefore, the link bearing 9 is urged by the blocking spring 12 so that the pawls 35 and 36 of the link bearing 9 and the connecting conductors are connected. 1
Until the stopper 23 and the stopper engaging projection 20 are engaged with each other with the engaging portions of the grooves 51 and 52 of the third fulcrum as a fulcrum, the contacts are rotated counterclockwise in the figure and the contacts are stably opened and closed. The contact surface of the latch 4 including the contact portions 24 and 25 with respect to the latch storage portion 65 has a case 1 size.
The state in which it is relatively above the latch receiving concave portion 65 inside is maintained.

At this time, the tip of the latch holding claw 70 is in contact with the holding claw sliding guide surface 66 of the case 1, the stopper 23 and the stopper engaging projection 20 are disengaged, and the latch 4 is removed from the latch accommodating recess 65 of the case 1. It does not fall out toward you.

Further, in any of the states of FIG. 1 and FIG.
In any of the transitions from FIG. 2 to FIG. 2 and from FIG. 2 to FIG. 1, the link spring 6 causes the stop faces 32, 3 of the link bearing 9 to move.
While in contact with 3, the second suspension portion 26 includes the first suspension portion 29, the end portion of the contact surface of the latch 4 on the ON side contact portion 24 side, OF
Virtual 3 made with 3 points at the end of the F side contact part 25 as vertices
The positional relationship between the first and second engaging portions is set so as to move within the prism.

Reference numeral 3 denotes an operation button, which has an abutting surface 71 on the outside of the case 1, an ON operation abutting portion 21 of the latch 4 on the inside of the case, and a latch 4 on the inside of the case.
An OFF operation contact portion 22 corresponding to the OFF contact portion 25 is provided, and a spring 5 that constantly urges the operation button 3 outward with respect to the case 1 is provided between the operation button 3 and the case 1. The operation button 3 is prevented from being pulled out of the case 1 by the edge frame 2 fitted in the case 1.

The circuit protector according to the present invention constructed as described above is manually moved by the operation of the operation button from the contact open state shown in FIG. 1 to the contact closed state shown in FIG. 2 as follows.

That is, in the state shown in FIG. 1, when the contact surface 71 of the operation button 3 is pressed to the right in the figure with the finger, the ON operation contact portion 21 of the operation button 3 causes the ON side contact portion 24 of the latch 4 to move. Since the latch 4 is pushed rightward in the figure, the latch 4 is pushed rightward in the figure in the handle accommodating recess, and the second suspension portion 26 also moves rightward in the figure. At this time, as described above, the second suspension portion 26 has the end portion on the contact surface ON side contact portion 24 side of the latch 4 and the OFF side contact portion 25.
Since the respective positional relationships are set so as to move only within the virtual triangle having the apex side end and the first suspension portion 29 as the apex, the ON side contact portion 24 of the latch and the second suspension portion 26 and the first suspension 29 are at least approximately in line, or the second suspension 26 is subject to a force to move further down in FIG. The tip of the holding claw 70 contacts the holding claw sliding guide surface 66 of the case and is prevented from moving downward in the figure. It is constrained so that it can only move to the right in the figure while being in contact with the holding claw sliding guide of the case. The rightward movement of the second suspension portion 26 is transmitted to the first suspension portion 29 via the link spring 6, and the first suspension portion has the link bearing 9 as described above.
Since it behaves as if it is almost integral with the contact spring 9, the link bearing 9 from the state shown in FIG. 1 uses the engaging portions of the claws 35, 36 and the engaging grooves 51, 52 of the connecting conductor 13 as fulcrums as fulcrums. It rotates clockwise in the figure against the rotational biasing force.

Eventually, a bimetal that rotates almost integrally with the link bearing 9
The movable contact 15 fixed to 11 approaches and contacts the fixed contact 16 to electrically close the terminals 58 and 55.

Further, if the ON-side contact surface 71 of the operation button 4 is pressed continuously, the tip of the holding claw 70 exceeds the holding claw sliding guide surface 66 while the movable contact is operated as the fixed contact due to the bending of the bimetal. Since there is nothing that prevents the second suspension portion 26 from moving downward in FIG. 1, the tip portion of the holding claw 70 and the second suspension portion suddenly move downward in FIG. At this time, the latch spring 7 is urged in the direction opposite to the moving direction, but the second suspension portion moves downward in the figure against the urging force by the operation button operating force of the finger.

After that, when the finger is released from the contact surface 71 of the operation button 3, the second suspension portion 26 uses the contact pressure between the contact points as a drag force and the link bearing 9
Rotates counterclockwise in the figure and moves to the left in the figure in accordance with the rotation, and tries to return to the original position, but when it returns slightly to the original position, this time with the inclined surface 27 of the latch holding claw 70. , The inclined surface 67 of the holding claw engaging protrusion 18 of the case engages, and as described above, the inclined surface is formed in the second line with respect to the straight line connecting the second suspension section 26 and the first suspension section 29. Since the suspension portion 26 is selected at an angle such that the engagement becomes deeper when the suspension portion 26 tries to move to the left in the figure by the reaction force of the contact pressure, the engagement is maintained and the contact closed state and the latched state are maintained. Is maintained as in FIG.

The contact pressure between the contacts is generated by the bending of the link spring 6 and the bending of the bimetal with respect to the link bearing 9 in the state shown in FIG.

Next, in order to manually shift from the contact closed state shown in FIG. 2 to the contact opened state shown in FIG. 1, the contact surface 71 of the operation button 3 in the state shown in FIG. When pressed with, the operation button 3 turns off.
The operation contact portion 22 and the OFF-side contact portion 25 of the latch 4 come into contact with each other, the holding claw 70 of the latch moves to the right in the figure, and the inclined surface 67 of the holding claw engagement projection 18 of the case 1 and the latch 4 of the case 1. Inclined surface of holding claw 70
Since the second suspension part 26 is separated from the second suspension part 27, the second suspension part 26 is in a virtual triangle whose apexes are the ends of the contact parts 24 and 25 of the contact surface of the first suspension part 29 and the latch. When the OFF-side contact portion 25 of the latch is pressed rightward in the drawing against the first suspension portion 29 whose position is restricted, the second suspension portion 26 moves upward in the drawing, that is, the holding claw engaging protrusion. 18 moves in the direction in which the first engagement between the holding claw 70 and the holding claw 70 is released.

If the contact surface of the operation button 3 is continuously pressed as it is, the inclined surfaces 67 and 27 are completely disengaged, and even if the second suspension portion 26 moves to the left side in the drawing, the engagement is stopped. Second suspension
26 moves up.

Next, when the finger pressing the operation button 3 is released, the link bearing 9 is rotated in the same direction by the urging force of the breaking spring 12 to the link bearing 9 in the counterclockwise direction in the figure, The movable contact 15 is separated from the fixed contact 16, and the biasing force of the latch spring 7 causes the latch 4 and the link spring 6 to bend at the angle shown in FIG. 1 so that the first engaging portion does not engage again. While maintaining the position, the second suspension 26 moves to the left in the figure,
Latch stopper 23 and case 1 stopper engaging protrusion
It stops at the position where it abuts 20, and holds the state at the contact open position shown in FIG.

Further, a case where the energized current reaches the size of the overcurrent region from the state where the contact is "on" as shown in FIG. 2 will be described with reference to FIGS.

In FIG. 2, when the current flowing between the terminals 58 and 55 reaches the magnitude of the overcurrent region, self-heating due to the current flowing in the bimetal 11 causes the both ends of the bimetal to be fulcrums to the high expansion side 42 side of the central portion. Is excessively curved, and finally, the bimetal contact surface 30 of the link 8 in the state shown in FIG.
It tries to rotate clockwise with 31 as the fulcrum,
Initially, in FIG. 2, the contact force of the contact pressure is applied in the direction of contracting the space between the second suspension portion 26 and the engaging portion 31, so that the force that tends to move the intermediate first suspension portion 29 downward. However, the link does not rotate, exceeding the bending force of the bimetal. When the bending force of the bimetal becomes further excessive, the link 8 finally rotates in the clockwise direction in the figure, and the line segment connecting the second suspension portion 26 and the engagement portion 31 is used as the dead point, and the first suspension portion is reached. When 29 exceeds the dead point on the opposite side, that is, slightly above the line segment in the figure, there is no support for the biasing force of the breaking spring 12 to the link bearing 9 in the counterclockwise direction in the figure, and Due to the rotational urging force, the link bearing 9 rotates counterclockwise in the figure with the engaging portions of the engaging portions 51 and 52 of the claws 35 and 36 and the connecting conductor 13 as a fulcrum, and the contacts are separated. The link 8 is an engaging portion
As the 31 fulcrum, it rotates clockwise in the figure to reach the state shown in FIG.

FIG. 3 shows a state in which the operation button 3 is pressed to the right in the end figure, but when the constraint of the operation button to the right is released from the state in FIG. The force that restrains the suspension portion 29 at the positions of the stop surfaces 32, 33 of the link bearing 9 has been released,
Since the first engagement between the inclined surfaces 27 and 67 is also released, the biasing force of the latch spring 7 causes the second suspension portion 26 to move upward in FIG. The suspension portion 29 has a structure in which the first suspension portion 29 is formed into a third portion by bending the latch spring 7.
While moving from the position shown in the drawing to the position shown in FIG. 1, the second suspension portion 26 moves to the left in the drawing due to the respective positional relationships,
It completely returns to the position shown in Fig. 1 and becomes stable.

[Effect of device]

As described above, according to the present invention, Japanese Patent Application No. 62-191048
On the other hand, by installing an operation button equipped with an ON operation contact part and an OFF operation contact part via a spring that always urges the case outward, and by providing a retaining means from above the case,
At the time of F operation, push button operation position is turned on as in Japanese Patent Application No. 62-191048
It has an effect that a circuit protector capable of shifting from ON to OFF and from ON to OFF can be obtained by pushing once regardless of which position of the operation button is pressed, without being restricted to the OFF side.

In addition, it is equipped with a just-reset type trip-free mechanism and has a small number of parts. Most of them are assembled by insertion and fitting, which is labor-saving and can be provided at low cost.

[Brief description of drawings]

 Fig. 1 is a sectional view in the "off" state. Fig. 2 is a sectional view in the "on" state. Fig. 3 is a sectional view in the "automatic shutoff" state. Fig. 4 is an exploded view of the main parts. 4 …… Latch 5 …… Spring 6 …… Link spring 7 …… Latch spring 8 …… Link 9 …… Link bearing 11 …… Bimetal 12 …… Interrupting spring 13 …… Connecting conductor 15 …… Moveable contact 16 …… Fixed Contact 18 …… Engagement protrusion 20 …… Stopper engagement protrusion 21 …… ON operation contact part 22 …… OFF operation contact part 23 …… Stopper 24 …… ON side contact part 25 …… OFF side contact part 26 …… Second suspension section 27 …… Sloping section 28 …… V-shaped groove 29 …… First suspension section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-64-33824 (JP, A) JP-A-63-81720 (JP, A) Actually open 63-633943 (JP, U) Actual-open Sho-56- 13325 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A movable contact and at least a first suspension portion are substantially integrally formed with each other, and the movable contact and the fixed contact are provided in accordance with the swing of the first suspension portion whose movement locus is restricted. A link bearing that opens and closes by being directly or indirectly suspended between the link bearing and the case to constantly urge the link bearing in the contact opening direction, one end of which is the first of the link bearings. Link spring, which is rotatably supported by the suspension part, and whose other end is rotatably supported by a second suspension part provided on a handle described later, a main body part, and a projection part protruding from the main body part. The main body has contact surfaces, and both ends of the contact surface have ON-side contact parts and OFF-side contact parts.
Side contact portion, the protrusion is formed on the side opposite to the contact surface of the main body, and the tip end of the protrusion has an inclined surface and the contact surface is turned off from the ON side contact portion. The holding claw extending substantially parallel to the contact surface toward the side contact portion, the second suspension portion provided in the vicinity of the retaining claw, the latch having the stopper, and the suspension claw suspended between the latch and the link spring, and the retaining claw at all times. And a latch spring for bending and urging the latch and the link spring in a direction in which the holding claw engaging projection of the case is disengaged, and a latch storing recess and a mechanism storing portion are provided between the latch storing recess and the mechanism storing portion. The holding claw includes a case having a holding claw engaging projection having an inclined surface corresponding to the holding claw of the latch and a holding claw sliding guide surface, and a stopper engaging projection similarly corresponding to the stopper of the latch. And the inclined surface of the holding claw engaging projection are paired to form the first engaging member. And the stopper and the stopper engaging projection form a pair to form a second engaging portion, and the second suspension portion has the mechanism accommodating portion side when the first engaging portion is engaged. And the latch engagement recess side when the second engaging portion is engaged, and the first suspension portion is oscillated via the link spring according to each position of the second suspension portion. The second suspension portion is in the closed position when the second suspension portion is in the engaged position, and the contact point is in the open position when the second suspension portion is in the engaged position. The second suspension portion is in the position, and in the state in which either the first engagement portion or the second engagement portion is engaged, or in the intermediate transition process thereof, the second suspension portion and the first suspension portion, Latch contact surface ON
The holding claw engaging projections and the stopper engaging projections are arranged and formed in the case at positions where the side contacting end and the OFF side contacting end are constrained within a range within a virtual triangle. When the engaging portion is engaged, the first suspension portion and the second suspension portion
With respect to the line segment connecting the suspension parts of, the inclined surface of the latch holding claw and the inclined surface of the case holding claw engaging protrusion are inclined at an angle such that engagement is deepened by the reaction force of the contact pressure of the contact point, The link bearing and the first suspension portion are substantially integrally combined with each other via the engaging means, and the link bearing of the engaging means is coupled by the overload detecting means substantially integrally combined with the link bearing. And the first suspension portion are disengaged from each other, and the operation surface, the ON-side contact end portion and the OFF-side contact end portion of the latch are provided on the outer side of the case of the recess of the latch housing portion of the case. It is characterized by comprising a corresponding ON operation contact portion, OFF operation contact portion, an operation button provided with a means for retaining the case, and a spring for constantly urging the operation button outward of the case. circuit protector.