JP3304673B2 - Circuit breaker - Google Patents

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 a distribution board.

[0002]

2. Description of the Related Art FIG.
It is a front view showing the internal structure of the conventional circuit breaker shown in Japanese Unexamined Patent Application Publication No. 4 (JP-A) No. 4 (1999). In the figure, reference numeral 1 denotes a case made of a molded article of an insulating resin, which is formed by a base 1a and a cover 1b. Reference numeral 2 denotes a handle pivotally supported between the base 1a and the cover 1b, and a recess 2a is formed in an extended portion extending into the case 1. Reference numeral 3 denotes a fixed contact, 4 denotes a fixed terminal formed by extending a conductor to which the fixed contact 3 is fixed, 5 denotes a movable contact to which a movable contact 6 opposed to the fixed contact 3 is fixed, and an end 5a is a handle. 2 is engaged with the concave portion 2a. Reference numeral 7 denotes a flexible conductor having one end connected to the movable contact 6 and the other end connected to the bimetal 8, and 9 a load-side terminal, one end of which is connected to the bimetal 8. Reference numeral 10 denotes a cradle, and a support portion 10a at one end is rotatably supported,
A latch 10b at the other end is locked by a locking portion 12a provided on a trip plate 12, which will be described later. 11 is an opening / closing spring,
It is stretched between the middle part of the cradle 10 and the movable contact 5. Reference numeral 12 denotes a release plate, which is shown in FIGS.
Has a pair of arms 12b, 12b on both sides as shown in FIG.
Supporting portion 1e of base 1a and supporting portion 1f of cover 1b
It is supported rotatably. 13 is a return spring,
One end thereof abuts at a substantially right angle to the release plate 12,
The release plate 12 is constantly biased clockwise. Reference numeral 14 denotes an iron piece fixed to one end of the bimetal 8, and reference numeral 15 denotes an adjusting screw that is screwed to the load-side terminal 9 and adjusts the positional relationship between the bent portion 12c of the release plate 12 and the bimetal 8.

The cradle 10, the opening / closing spring 11, the extension of the handle 2 and the movable contact 5 form a well-known toggle mechanism.
The fixed contact 3 and the movable contact 6 are brought into contact with and separated from each other by a toggle mechanism, so that an on / off operation is performed. When an abnormal current flows, the trip plate 12 is attracted to the iron piece 14 and moved rightward by the bending of the bimetal 8 due to the overcurrent or the electromagnetic force due to the short circuit current as shown in FIG. Of the latch 10b comes off the locking portion 12a,
The movable contact 6 is separated from the fixed contact 3 by the urging force of the opening / closing spring 11 and trips.

[0004]

Generally, it has been necessary to confirm the operation of the internal mechanism of this type of circuit breaker by performing opening / closing operation by a handle operation and manual trip operation in a state where power is not supplied during assembly. However, in the above-described conventional circuit breaker, the arm 12b of the tripping plate 12 is supported by the support 1e of the base 1a and the support 1f of the cover 1b. The arm 12b of the tripping plate 12 is the support 1
e, the tripping plate 12 floats up during the above operation and comes off the support portion 1e, and the above operation cannot be confirmed. For this reason, there is a problem that a temporary cover having a hole formed in the cover 1b must be attached so that the internal mechanism can be seen, and the operation must be checked.

[0005] As shown in FIGS. 10 and 11,
The engagement between the latching portion 12a of the release plate 12 and the latch 10b is in contact only with the plate thickness of the cradle 10, and when the cradle 10 is inclined to one side,
Alternatively, when the contact surface is formed to be inclined, a concentrated load is applied to the contact surface, and the frictional force is increased, so that the tripping time is prolonged. There was a problem.

[0006] As shown in FIG.
In this case, a pair of arms 12b, 12b of the tripping plate 12 are provided with convex portions on the housing 1 and a cover (not shown) to suspend the latch 10b. Cradle 10
Is tilted as shown by the dashed line, the cradle 1
There is a problem that the contact state between the zero latch 10b and the locking portion 12a is line contact, and the frictional force is increased and the wear is accelerated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to stabilize the trip characteristic.
Thus, a circuit breaker is provided.

[0008]

[0009]

A circuit breaker according to the present invention comprises a handle pivotally supported by a base and a cover;
A movable contact that is connected to a handle and has a movable contact fixed to the tip
The contactor is provided so as to be able to contact and separate from the movable contact.
The fixed contact and the tripping plate
Curved or U-shaped to surround this bimetal
The electromagnetic attraction force generated by the fixed iron piece fixed to the base
A trip device that is displaced by
It is rotatably supported and the other end is engaged with the locking portion of the trip plate.
Between the cradle to be stopped and the movable contact
Circuit breaker with an open / close spring stretched on
The above-mentioned fixed iron piece is provided facing the U-shaped end face of the fixed iron piece.
When the normal current is detected, it is sucked in the displacement direction of the trip plate.
Move the movable iron piece on the cradle side with the release plate.
Suspended on the support arm of the base, and
Make sure that the release plate does not contact the fixed iron piece when raw
It is constituted in.

Further, the trip plate is engaged with the support arm of the base at one point.

The movable iron piece is tripped on its operating side.
It is arranged with an interval to the plate.

[0012]

In the circuit breaker constructed as described above , the tripping plate contacts the fixed iron piece when an abnormal current occurs.
And does not hinder the bending due to the temperature rise of the bimetal.

Further, even if the contact surface of the locking portion between the cradle and the trip plate is inclined, the trip plate is inclined in accordance with the inclination, and the surface contact of the contact surface is ensured.

Also, the movable iron piece is moved by the initial movement by the electromagnetic attraction force.
Move.

[0015]

【Example】

Embodiment 1 FIG. FIGS. 1 and 2 show a main structure inside a circuit breaker according to an embodiment of the present invention. FIG. 1 is a front view showing a closed state of the circuit breaker, and FIG. 2 shows a trip state of the circuit breaker. FIG. FIG. 3 is a perspective view showing a cradle, and FIG.
FIG. 4 is a cross-sectional view showing a state where a tripping plate is incorporated in a case. In the figure, 3, 4, 6 to 9, 11, 13, 1
Reference numeral 5 has the same configuration as that of the above-described conventional example, and a description thereof will be omitted. Reference numeral 100 denotes a circuit breaker case, which is formed of a base 31 and a cover 32 made of a molded product of an insulating resin. The base 31 has an opening closed on one side by a cover 32. A cradle support portion 31a having a substantially V-shaped cross section and a support arm 31b having a substantially U-shaped groove portion 31c formed along the projecting direction are provided on the inner surface of the base 31 so as to protrude. Reference numeral 33 denotes a handle, which includes a rotation support shaft 33a pivotally supported by the base 31 and the cover 32, and an engagement shaft 33 which forms a support shaft of a toggle mechanism by engaging with a movable contact described later.
b. Reference numeral 34 denotes a cradle formed by bending a flat plate material in a direction perpendicular to the rotation direction. One end of the cradle is engaged with and supported by the cradle support portion 31a and serves as a rotation fulcrum. It has a latch 34b which is locked to the cradle locking portion 36a of the release plate 36. The cradle 34 has a spring hook 34c for locking one hook of the opening / closing spring 11, and a kick piece 34d extending horizontally between the support portion 34a and the latch 34b. Reference numeral 35 denotes a base end 35b having an engagement shaft 33b of the handle 33.
The movable contact 6 is engaged with and connected to the movable contact 6. The movable contact 6 has a movable contact 6 that comes into contact with and separates from the fixed contact 3 and a spring hook 35 a that locks the other hook of the opening / closing spring 11.

Reference numeral 200 denotes a tripping device, which includes a bimetal 8 having one end connected to the load terminal 9, a tripping plate 36,
The movable iron piece 37, the fixed iron piece 38, the spring 13, and the adjustment screw 15 are provided. The tripping plate 36 is made of a magnetic material, and is rotatably suspended on a support arm 31 b provided on the base 31. In addition to the cradle locking portion 36a which is partially opened, the tripping plate 36 has a spring support piece 36b which is formed to be inclined at one end and supports the spring 13, and is bent at an L-shaped right angle at the other end. A bimetal engagement portion 36c that is engaged when the bimetal 8 is bent, and a locking portion 36 that is inserted into the groove 31c of the support arm 31b provided on the base 31.
d. The movable iron piece 37 is rotatably suspended by inserting a locking portion 37 a formed by cutting out a part thereof into a groove 31 c of a support arm 31 b provided on the base 31. The movable iron piece 37 is placed side by side on the cradle 34 side of the tripping plate 36, and its operation side is the tripping plate 36.
With a slight gap D. Fixed iron piece 3
Numeral 8 is formed by bending in a U-shape so as to surround the bimetal 8, and is disposed such that an end face 38 a thereof faces the movable iron piece 37. Both ends of the fixed iron piece 38 are held by pins 31q protruding from the base 31 and pins 32a protruding from the cover 32. The spring 13 is fitted on the spring supporting piece 36b of the release plate 36, one end of the spring 13 is in the bent portion of the spring supporting piece 36b, and the other end is the concave portion 31 of the base 31.
d. The spring 13 is disposed to be inclined with respect to the tripping plate 36, and the upper portion of the tripping plate 36 is slightly displaced upward from the fulcrum in an obliquely upward direction against the displacement direction of the tripping plate 36. It is energizing.

Next, the operation will be described. In the closed state shown in FIG. 1, when an abnormal current, for example, an overcurrent flows in the circuit, the bimetal 8 is bent, and the tripping plate 36 is moved rightward in the drawing by the engagement between the bimetal 8 and the bimetal engaging portion 36c. The latch 34b of the cradle 34 is disengaged from the cradle engaging portion 36a of the release plate 36, and the movable contact 35 is rotated counterclockwise by the opening force of the opening / closing spring 11, and the trip state shown in FIG. When a short-circuit current flows, the fixed iron piece 38, the trip plate 36 and the movable iron piece 37
The release plate 36 is moved rightward in the figure due to the electromagnetic attraction generated between the release plate 36 and the cradle 34, and the latch 34b of the cradle 34 is disengaged from the cradle engaging portion 36a of the release plate 36. The movable contact 35 is rotated counterclockwise, and the trip state shown in FIG. 2 is set. The normal opening / closing operation is performed by turning the handle 33.

In the circuit breaker thus constructed, the tripping plate 36 is biased by the spring 13 with the fulcrum slightly shifted from an obliquely upward direction, so that the vertical component is applied to the support arm 31b serving as the fulcrum. Since it acts in the pressing direction, the support position of the release plate 36 is changed to the support arm 3 of the base 31.
1b can be stably held in the groove portion 31c, and when the latch 34b is reset to the cradle engaging portion 36a, the lifting plate 36 can be prevented from rising upward. Further, since the horizontal component acts as a restoring force of the trip plate 36 displaced by the abnormal current, the trip plate 36 is rotated clockwise after the trip operation to return.

Therefore, according to this embodiment, since the components such as the handle 33, the cradle 34, and the release plate 36 are supported only by the base 31, the opening / closing operation by the handle operation or the manual operation by the handle without electricity during assembly is performed. When the operation of the internal mechanism is checked by performing the trip operation, the operation of the opening / closing mechanism can be checked with the cover 32 removed.

Embodiment 2 FIG. Also, as shown in FIGS. 1 and 6, a movable iron piece 37 is superposed and juxtaposed on the cradle 34 side of the tripping plate 36, and the movable arm 37 is provided on the base 31 together with the tripping plate 36. 31 b is rotatably suspended and arranged at a small interval with respect to the end face 38 a of the fixed iron piece 38, so that a strong current is generated between the fixed iron piece 38 and the movable iron piece 37 by the current flowing through the bimetal 8 when an abnormal current occurs. Electromagnetic attraction is generated. Further, the latch 34b is locked to the tripping plate 36, and the tripping plate 36 is difficult to be initially moved. However, since the movable iron piece 37 has no load, it is moved in the gap D by the initial movement by the electromagnetic attraction. It collides with the release plate 36 and assists the initial movement of the release plate 36 in the direction of the release operation.
Furthermore, if the bimetal 8 is prevented from bending due to a temperature rise when an abnormal current is generated, a permanent distortion occurs and the tripping characteristic is impaired. In the present embodiment, the tripping plate 36 is set so as not to contact the fixed iron piece 38. The configuration does not hinder the bending of the bimetal 8.

Therefore, according to the second embodiment, the tripping plate 36 does not hinder the bending of the bimetal 8, and the movable iron piece 37
The trip operation can be accelerated by the electromagnetic force generated in the motor.

Embodiment 3 FIG. FIG. 7 shows another embodiment in which the tripping plate 36 is supported on the base 31. The locking portion 36d of the tripping plate 36 is formed to have a convex curved surface, and
At one point with the groove 31c of the support arm 31b provided on the support arm 31b. According to this embodiment, the tripping plate 36 is engaged with the locking portion 36d of the groove 31c of the support arm 31b of the base 31.
Is suspended at one point of the convex curved surface of the cradle 34 and is pressed by the spring 13, so that even if the latch 34b of the cradle 34 is inclined, the locking portion 36d freely rotates in accordance with the inclination, and the plane of the latch 34b And the cradle engaging portion 36a are corrected so that the entire surface always contacts. For this reason, the contact between the latch 34b and the cradle engaging portion 36a is in surface contact, so that stable tripping characteristics can be obtained, and the wear of the contact surface is reduced.

Embodiment 4 FIG. In the third embodiment, the tripping plate 36 is connected to the support arm 31b at one point of the convex curved surface of the locking portion 36d.
, The latch 36b can rotate so that the latch portion 36d comes into surface contact with the inclination of the latch 34b. On the other hand, the torsional rotation about the suspension direction of the tripping plate 36 is performed. Easy to occur. This torsional rotation is performed by the latch 34 b and the locking portion 36.
By changing the engagement allowance (meaning allowance) of d, the trip time at the time of overcurrent is varied. Therefore, in the fourth embodiment, as in the second embodiment, the movable iron pieces 37 are arranged side by side on the cradle 34 side of the tripping plate 36, and are suspended in the bearing grooves 31b. According to this configuration, since the fulcrum 37a of the movable iron piece 37 is formed linearly and uses the support arm 31b as a support shaft,
The torsional rotation about the hanging direction of the tripping plate 36 is not performed. Therefore, the torsional rotation of the tripping plate 36 is prevented by the movable iron piece 37, and a stable tripping operation without variation in the tripping time limit can be obtained.

[0024]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, the base and the cover are provided.
Handle and the tip connected to this handle
A movable contact with a movable contact fixed to the portion, and the movable contact
Fixed contact provided opposite to and away from
The trip plate is bent by bimetal bending or this bimetal
Formed in a U-shape to surround the base and fixed to the base
To be displaced by electromagnetic attraction force generated by fixed iron pieces
One end is rotatably supported on the removal device and the base, and the other
The end is a cradle that is locked to the locking portion of the release plate,
An open / close spring stretched between the cradle and the movable contact
The circuit breaker provided with
Is provided to face the end face of
The movable iron piece sucked in the displacement direction of the trip plate is
Overlay the release plate on the leddle side and attach the support arm of the base
At the time of occurrence of the abnormal current, and
Is designed so that it does not contact the fixed iron piece.
Normal current is generated, and the tripping plate is displaced by electromagnetic attraction.
The bimetal does not have permanent set when
A stable circuit breaker can be provided.

According to the second aspect of the present invention, since the tripping plate is engaged with the support arm at one point, the tripping plate is inclined even if the contact surface between the latch and the locking portion of the tripping plate is inclined. Therefore, the contact surface can be reliably contacted, so that stable tripping characteristics can be obtained and wear of the contact surface can be reduced.

According to the third aspect of the present invention, the movable iron piece is
Working side is spaced with respect to the trip plate
Therefore, the initial movement of the tripping plate in the direction of the tripping operation is assisted.

[Brief description of the drawings]

FIG. 1 is a front view showing an internal configuration of a circuit breaker according to the present invention in a closed state.

FIG. 2 is a front view showing an internal configuration of the circuit breaker of the present invention in a trip state.

FIG. 3 is a perspective view showing a cradle according to the present invention.

FIG. 4 is a cross-sectional view showing a state in which a trip plate is incorporated in the case of the circuit breaker of the present invention.

FIG. 5 is a front view showing a movable iron piece according to the present invention.

FIG. 6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a sectional view showing another embodiment of the circuit breaker of the present invention in which a trip plate is incorporated in a case.

FIG. 8 is a front view showing an internal configuration of a conventional circuit breaker in a closed state.

FIG. 9 is a front view showing an internal configuration of a conventional circuit breaker in a trip state.

FIG. 10 is a cross-sectional view showing a state in which a conventional tripping plate is assembled.

FIG. 11 is a perspective view showing a conventional state of engagement between a trip plate and a cradle.

FIG. 12 is a front view showing an engagement state between a conventional trip plate and a cradle.

[Description of Signs] 3 Fixed contact 4 Fixed terminal 6 Movable contact 8 Bimetal 11 Opening / closing spring 13
Spring 31 Base 31a Cradle support 31b
Bearing arm 31c Bearing groove 32 Cover 33
Handle 34 Cradle 35 Movable contact 36
Release plate 37 Moving iron 38 Fixed iron

Claims (3)

(57) [Claims] 1. A handle pivotally supported by a base and a cover, a movable contact connected to the handle and having a movable contact fixed at a distal end portion, and a fixed member provided to face the movable contact so as to be able to contact and separate from the movable contact. and contact, bar the trip plate by an abnormal current
Curve the metal or cover it so that it surrounds the bimetal.
A fixed iron piece formed in the shape of a letter and fixed to the base
A trip device that is displaced by an electromagnetic attraction force, a cradle one end of which is rotatably supported by the base and the other end of which is locked by a locking portion of the trip plate, between the cradle and the movable contact. A circuit breaker having an open / closed spring that is stretched, wherein the different
When the normal current is detected, it is sucked in the displacement direction of the trip plate.
Move the movable iron piece on the cradle side with the release plate.
Suspended on the support arm of the base, and the trip plate is fixed when the abnormal current occurs.
A circuit breaker characterized in that it does not come into contact with an iron piece . 2. The circuit breaker according to claim 1, wherein the trip plate is engaged with the support arm of the base at one point. 3. The movable iron piece is provided with a tripping plate on its operating side.
Claims characterized by being arranged with an interval to
3. The circuit breaker according to 1 or 2.