JPH08153454A - Circuit breaker - Google Patents

Abstract

PURPOSE: To easily transfer the arc generated at the interruption of a cable run with an inexpensive structure by protruding a metal mounting screw formed of a magnetic body for fixing a fixed contact to an insulating case to the vicinity of a fixed contact. CONSTITUTION: At contact opening, an arc A is generated between a movable contact 1a and a fixed contact 13a. This arc is guided in an arrowed direction by the electromagnetic force, and transferred to a mounting screw 7 as shown by an arc C. In this case, since the mounting screw 7 is protruded to the vicinity of the fixed contact 13a, the arc A is quickly transferred from the fixed contact 13a to the top end part of the mounting screw 7, and reaches an arc extinguishing grid, in which it is extinguished. Thus, the remarkable wear of the fixed contact 3b by arc can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker, and more particularly to a circuit breaker suitable for easily inducing an arc generated when the electric circuit is cut off.

[0002]

2. Description of the Related Art Conventionally, a circuit breaker of this type is shown in FIG. In the figure, an arc extinguishing grid 2 is provided in front of a movable contact 1 having a movable contact 1a,
A fixed contact 3a is fixed to one end of the fixed contactor 3, and a plate-shaped arc runner 4 made of metal is attached to a conductor 3b to which an external conductor (not shown) is connected at the other end. The fixed contactor 3 is fixed to the insulating case 5 with a fixing screw 6. In the electric path, when the movable contact 1 is closed, a current flows from the movable contact 1a through the fixed contact 3a and the conductor 3b.

With the above structure, when an overload current flows in the electric circuit, a current detection relay (not shown) operates to mechanically open the movable contact 1 as shown in FIG. This time,
An arc A is generated between the movable contact 1a and the fixed contact 3a. This arc is guided by the electromagnetic force in the direction of the arrow, moves to the arc runner 4 as shown by the arc B, reaches the arc extinguishing grid 2, and is extinguished. As a result, the fixed contact 3
It is possible to prevent remarkable wear due to the arc of a.

[0004]

In the conventional circuit breaker as described above, since the arc runner 4 for guiding the arc generated when the electric circuit is cut off is mounted on the fixed contactor 3, the manufacturing cost of the arc runner is reduced. Also, there is a problem in that the attachment cost to the fixed contact is high.

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a circuit breaker which can easily transfer an arc with an inexpensive structure.

[0006]

In the circuit breaker according to the present invention, there is provided a fixed contact having a conductor housed in an insulating case and having a fixed contact fixed to one end thereof which can be contacted and separated from the movable contact, and a fixed contact. A metal member for fixing the fixed contact to an insulating case in front of the fixed contact, wherein the metal member is provided so as to protrude to the vicinity of the fixed contact.

Further, the metal member is a screw which penetrates the insulating case and is screwed into the conductor of the fixed contact.

Further, a small diameter portion is formed at the tip of the screw.

Furthermore, the tip portion of the screw is bent in a direction away from the fixed contact to form an inclined portion.

[0010]

In the circuit breaker constructed as described above, the foot of the arc generated when the electric circuit is cut off is transferred from the fixed contact to the tip of the metal member.

Further, the foot of the arc is moved from the fixed contact to the tip of the screw.

Further, the foot of the arc is quickly transferred from the fixed contact to the small diameter portion of the screw.

Furthermore, the foot of the transferred arc runs on the inclined portion.

[0014]

【Example】

Example 1. 1 to 4 each show a circuit breaker according to an embodiment of the present invention. FIG. 1 is a side sectional view showing an on state, FIG. 2 is a side view of a main part showing an off state, and FIG. It is a side view which shows a trip state. In the figure, reference numeral 1 denotes a movable contactor having a movable contact 1a, which is rotatably supported by a shaft 6a provided on a movable arm 6. Reference numeral 2 is an arc-extinguishing grid provided in front of the movable contact 1, 3 is a fixed contact having a conductor 3b bent in a substantially U shape, and one end of the conductor is in contact with the movable contact 1a. The fixed contact 3a which separates is fixed, and an external conductor (not shown) is connected to the other end. Reference numeral 7 denotes a metal mounting screw made of a magnetic material such as iron, that is, a metal member, which penetrates the insulating case 5 in front of the fixed contact 3 and is screwed to the conductor 3b of the fixed contact 3, and which has a full length. Thus, the screw portion 7a is formed, and the screw portion 7a is provided so as to protrude to the vicinity of the fixed contact 3a. In this embodiment, the tip of the screw 7 is located above the upper surface of the fixed contact 3a, but it may be at the same height as the upper surface.

Reference numeral 8 is a frame installed in the insulating case 5, 9 is an overcurrent responding device, and includes an electromagnetic coil 9a and a yoke 9b.
And a movable iron piece 9c and a pulling spring 9d for constantly urging the movable iron piece toward the anti-electromagnetic coil side. 1
Reference numeral 0 is a trip bar that is operated by the suction operation of the movable iron piece 9c, and 11 is a latch that is attached to the trip bar 10 and that is rotated by the operation of the trip bar 10, and is rotatably supported by the frame 8 by a pin 12. 13 is a latch 1
A torsion spring that always urges 1 clockwise, 14 is a latch 1
The pin 1 is a latch that rotates when it is disengaged by the rotation of 1.
A frame 5 rotatably supports the frame 8. 16
Is a torsion spring that constantly urges the latch 14 clockwise, 1
7 is an operation handle protruding from the insulating case 5 to the outside.
It rotates with a part of the frame 8 as a fulcrum. A toggle link mechanism 18 includes an upper link 18a connected to the operation handle 17 and a lower link 18b connected to the movable contact 1.
And a pin 18c connecting both links. Reference numeral 19 is a tension spring stretched between the pin 18c and the operating handle 17, and 20 is a lever, a part of which is rotatably connected to the upper end of the upper link 18a, and is locked to the notch 14a of the latch 14. It is also rotatably supported by the frame 8 by the pin 21.

Next, the operation will be described. In the ON state shown in FIG. 1, the operation handle 17 is turned OFF (arrow 2
(Direction 2), the line of action of the tension spring 19 changes to collapse the toggle link mechanism 18. Then, the movable contact 1 is pulled up by the toggle link mechanism 18 and separated from the fixed contact 3. This off state is shown in FIG.

Next, when an overload current flows in the ON state of FIG. 1, the movable iron piece 9c is attracted to the electromagnetic coil 9a side, the trip bar 10 is pushed by the tip of the movable iron piece 9c, and the latch 11 twists the spring 16. To rotate clockwise.
Then, the latch 14 is disengaged from the latch 11 and rotated counterclockwise by the twist spring 16, so that the lever 20 disengages from the notch 14a of the latch 14 and pivots clockwise to collapse the toggle link mechanism 18 and pull it. The pulling force of the spring 19 separates the movable contact 1. This trip state is shown in FIG.

When the contacts are separated as described above, an arc A is generated between the movable contact 1a and the fixed contact 3a as shown in FIG. This arc is guided in the direction of the arrow by the electromagnetic force and moves to the mounting screw 7 as shown by the arc C. In this case, since the mounting screw 7 is provided up to the vicinity of the fixed contact 3a, the arc A quickly moves from the fixed contact 3a to the tip of the mounting screw 7 and reaches the arc extinguishing grid 2 to extinguish the arc. To be done. As a result, it is possible to prevent the fixed contact 3b from being significantly consumed by the arc. According to this embodiment, by using the mounting screw of the fixed contactor in place of the conventional arc runner, the manufacturing cost of the arc runner and the mounting cost to the fixed contactor become unnecessary, and the structure can be constructed at low cost. Also, the mounting screws are easy to manufacture and easy to mount.

Example 2. Although the mounting screw 7 in which the screw portion 7a is formed over the entire length is shown in the first embodiment, in the second embodiment, as shown in FIG. 5, the tip of the mounting screw 70 is outside the screw portion 70a. Small diameter part 70 without screws with small diameter
b is formed. According to this embodiment, in addition to the effect of the first embodiment, the length of screwing the conductor 3a of the fixed contactor 3 and the mounting screw 70 is shortened, so that the mounting work time can be shortened.

Example 3. Further, as shown in FIG. 6, after the mounting screw 71 is screwed onto the conductor 3b of the fixed contactor 3, the tip portion thereof, that is, the portion protruding upward from the fixed contact 3a is moved away from the fixed contact 3a, that is, the arc extinguishing grid. The inclined portion 71a bent in the two directions may be formed. According to this embodiment, the arc transferred to the mounting screw 71 travels along the inclined portion 71a, so that the wear of the fixed contact 3a can be further reduced. . The small-diameter portion 70b formed on the mounting screw 70 as shown in FIG. 5 may be bent in a direction away from the fixed contact 3a. In this case, the same effect as that of the third embodiment can be obtained and the bending process is easy. Becomes

[0021]

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

By using a metal member for fixing the fixed contactor in place of the conventional arc runner, the manufacturing cost of the arc runner and the mounting cost to the fixed contactor are unnecessary, and the structure can be constructed at low cost.

Further, by using the screw as the metal member, the manufacture is simple and the mounting is easy.

By forming the small diameter portion at the tip of the screw, the arc can be transferred quickly and the screw length of the fixed contact and the mounting screw can be shortened, so that the mounting work time can be shortened.

By bending the tip of the screw in a direction away from the fixed contact to form an inclined portion, the arc transferred to the screw travels on the inclined portion, so that wear of the fixed contact 3a can be further reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an overall configuration of a circuit breaker that is Embodiment 1 of the present invention.

FIG. 2 is a side view of an essential part showing an off state of a circuit breaker.

FIG. 3 is a side view of an essential part showing a tripped state of the circuit breaker.

FIG. 4 is a main part explanatory diagram for explaining an operation.

FIG. 5 is a sectional view of a main part of a circuit breaker showing a second embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a circuit breaker showing a third embodiment of the present invention.

FIG. 7 is a partially cutaway side sectional view showing a conventional circuit breaker.

FIG. 8 is an explanatory diagram of a main part for explaining an operation.

[Explanation of symbols]

1 Moving contact 5 Insulation case 1a Moving contact 7 Mounting screw (metal member) 3 Fixed contact 3a Fixed contact 3b Conductor

Claims (4)

[Claims] 1. A fixed contactor having a conductor housed in an insulating case and having a fixed contact at one end fixed to a movable contact and a movable contact, and the fixed contactor fixed to the insulating case in front of the fixed contact. A circuit breaker characterized in that the metal member is provided up to the vicinity of the fixed contact. 2. The metal member is a screw penetrating the mold case and screwed into the conductor.
Circuit breaker described. 3. The circuit breaker according to claim 2, wherein a small diameter portion is formed at the tip of the screw. 4. The circuit breaker according to claim 1, wherein the tip of the screw is bent in a direction away from the fixed contact to form an inclined portion.