JP2002056762A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To intercept fusing bodies from adhering to a jointing section jointed with a latch receptacle of a trip crossbar, which are dispersed from an arc extinction equipment at the time of large current shut-off. SOLUTION: A protection cover 19 is equipped to a latch receptacle 13 which interrupts the scattering bodies of the arc extinction equipment 18 from the jointing section 16a jointed with the latch receptacle 13 of the trip crossbar 16. Since the scattering bodies which fly from the arc extinction equipment 18 side at the time of large current shut-off, are interrupted by the protection cover 19, the initial state of the jointing section 16a of the trip crossbar 16 is maintained after large current immediate shut down, and the over-current tripping function after re-setting a circuit breaker is not checked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker such as a wiring breaker or an earth leakage breaker which is used as an overcurrent protector in a switchboard or a control panel, and more particularly, to a method of shielding a splatter of molten material when a current is cut off. About the means.

[0002]

2. Description of the Related Art FIG. 3 is a schematic vertical sectional view of a circuit breaker showing a conventional configuration. In FIG. 3, a power supply terminal 2, a fixed contact 3 integrated with the power supply terminal 2, a movable contact 4 that comes in contact with and separates from the fixed contact 3 via a contact, and one end is a movable contact in a mold case 1. 4, a current path is formed by the coil 6 a of the overcurrent trip device 6, one end of which is connected to the other end of the lead wire 5, and the load-side terminal 7, to which the other end of the coil 6 a is connected. ing. An opening / closing handle 8 is rotatably supported on the mold case 1 by a shaft 9, and the movable contact 4 is connected to the opening / closing handle 8 via a shaft 10. Reference numeral 11 denotes a resin molded product latch which is rotatably supported at one end by the shaft 12 on the mold case 1, and the other end of which is locked by a latch receiver 13. An opening / closing spring 14 composed of a tension spring is hung between the latch 11 and the movable contact 4, and the movable contact 4 receives a clockwise rotational force about the shaft 10 as a fulcrum in the ON state shown in the drawing, and passes through the movable contact. The fixed contact of the fixed contact 3 is pressed with an appropriate contact pressure.

The latch receiver 13 is made of a steel plate, and a pair of left and right arms 13b is formed on both sides of a flat plate-shaped receiving portion 13a, and the upper end thereof is rotatably supported by a mold case 15 by a shaft 15. The upper end surface of the receiving portion 13a is formed as a slope as shown, and the latch 11 is engaged with this slope. The latch receiver 13 receives a counterclockwise rotational force from the latch 11 with the shaft 15 as a fulcrum. However, the latch receiver 13 is stopped by the trip crossbar 16 in which the claw 16a is engaged with the back surface of the receiver 13a. A window hole 13b is formed near a portion of the receiving portion 13a where the claw 16a is engaged. The trip crossbar 16 is a rod-shaped body made of resin, extends laterally across each pole of the circuit breaker, and is rotatably supported by the mold case 1. A trip piece 16b is provided on the trip crossbar 16 so as to face the armature 6b of the overcurrent trip device 6, and a reset spring 17 made of a compression spring is provided between the projecting piece 16b and the latch receiver 13. Has been inserted. Reference numeral 18 denotes an arc extinguishing device formed of a magnetic material in a U-shape, and installed upward so as to surround the opening / closing path of the movable contact 4.

In such a circuit breaker, when the open / close handle 8 is turned off rightward from the illustrated ON state, the connecting shaft 10 of the movable contact 4 is moved along the axis X of the open / close spring 14.
The contact between the movable contact 4 and the dead center passing from right to left in FIG.
, The movable contact 4 is separated from the fixed contact 3 by receiving a rotational force in the counterclockwise direction.

On the other hand, when the current becomes an overcurrent state, the overcurrent tripping device 6 sucks the armature 6b, and the armature 6b which has turned counterclockwise from the state shown in the drawing kicks the projecting piece 16b of the trip crossbar 16 at one end. Then, the trip crossbar 16 is rotated clockwise. As a result, the claw 16a is disengaged from the engagement portion of the latch receiver 13 and the window hole 13b
And the latch receiver 13 thus unlocked
Rotates counterclockwise and comes off the latch 11. Along with this, the latch 11 is also unlocked and rotates clockwise. When the axis X of the opening / closing spring 14 crosses the connecting shaft 10 of the movable contact 4 from left to right in FIG. 3, the spring action of the opening / closing spring 14 on the movable contact 4 is reversed, and The contact 4 receives the rotational force in the counterclockwise direction and separates from the fixed contact 3 (trip operation).
FIG. 4 shows this trip operation state. that time,
An arc is generated between the fixed and movable contacts, and this arc is attracted and extended by the arc extinguishing device 18 made of a magnetic material, and the arc voltage is increased to extinguish the arc.

[0006]

In the above-described conventional circuit breaker, the latch receiver 13 is provided around the arc extinguishing device 18, so that when a large current such as a short-circuit accident is interrupted, the arc receiver is turned off. The metal melt or vapor generated from the arc extinguishing device 18 due to the contact with the splatters is scattered as shown by the arrow in FIG. 4 and adheres to the engaging portion of the trip crossbar 16 with the latch receiver 13, that is, the claw 16a. was there. Therefore, when the circuit breaker is turned on again and used, the frictional force of the engagement surface between the latch receiver 13 and the claw 16a increases, and the engagement can be released even when the overcurrent trip device 6 operates. Therefore, there was a danger that shutoff would be impossible. The object of the present invention is to
An object of the present invention is to cope with such a phenomenon and to improve the operation reliability of the circuit breaker.

[0007]

In order to solve the above-mentioned problems, the present invention comprises a latch receiver installed around an arc extinguishing device, and a trip crossbar for locking the latch receiver from the back, The latch receiver always locks the latch receiving the spring force of the opening / closing spring between the movable contact and the latch receiver. In the circuit breaker to open the movable contact by releasing
The latch receiver is provided with a protective cover for shielding an engagement portion of the trip crossbar with the latch receiver from flying objects of the arc extinguishing device (claim 1). Claim 1
According to the scattered matter flying from the arc extinguishing device side at the time of current interruption is blocked by the protective cover, so the engagement portion of the trip crossbar is maintained in the initial state, and it is assumed that the trip crossbar is turned on again after resetting the circuit breaker. Also, the overcurrent tripping function is not hindered by the flying objects. The protection cover may be provided with a receiving portion for a reset spring mounted between the latch receiver and the trip crossbar.

[0008]

FIG. 1 is a schematic longitudinal sectional view of a circuit breaker according to an embodiment of the present invention. In FIG.
The difference from the prior art is that the protective cover 19
Is attached. FIG. 2 is an enlarged perspective view of the protective cover 19. The protective cover 19 is formed of a heat-resistant resin into the shape shown in FIG. 2, and is fitted into the receiving portion 13a of the latch receiver 13 through the groove 19a from the lower end thereof. The recess 19 corresponds to the window hole 13 b of the latch receiver 13.
b is formed, and forms a relief portion when the claw 16a of the trip crossbar 16 falls into the window hole 13b. As shown in FIG. 1, the protective cover 19 covers the window hole 13 b of the latch receiver 13 from the arc extinguishing device 18 side, and covers an engagement portion (claw 16 a) of the trip crossbar 16 with the latch receiver 13. Thereby, as shown in FIG. 3, even if molten metal or vapor scatters from the arc extinguishing device 18 toward the latch
It does not adhere to a. In FIG. 2, the protective cover 19 is provided with a circular concave portion 19c as a spring receiving portion. As shown in FIG. 1, one end of the reset spring 17 is received by the circular concave portion 19c. Since the spring receiving concave portion 19c can be formed at the same time when the protective cover 19 is formed, the spring receiving concave portion 19c is simpler and less expensive than forming a projection or the like on the latch receiver 13 by pressing.

[0009]

As described above, according to the present invention, a metal cover or the like at the time of current interruption is provided by mounting a protective cover on the latch receiver to shield the engagement portion of the trip crossbar with the latch receiver. Prevents the frictional force between the latch receiver and the trip crossbar from increasing due to adhesion, and maintains the overcurrent tripping function normally even when the circuit breaker is turned on again after a large current interruption such as a short circuit accident be able to.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a circuit breaker showing an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a protective cover in FIG.

FIG. 3 is a schematic longitudinal sectional view of a circuit breaker showing a conventional example.

FIG. 4 is a vertical sectional view of a main part showing a trip state of the circuit breaker of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 fixed contact 4 movable contact 6 overcurrent trip device 11 latch 13 latch receiver 16 trip crossbar 16a pawl 17 reset spring 18 arc extinguishing device 19 protective cover

Claims (2)

[Claims] The present invention comprises a latch receiver installed around an arc extinguishing device, and a trip crossbar for locking the latch receiver from the back. A circuit breaker that constantly locks the latch that receives the signal, and releases the lock by the trip crossbar when an overcurrent occurs, rotates and releases the lock of the latch to open the movable contact. A circuit breaker, wherein a protective cover for shielding an engagement portion of the trip crossbar with the latch receiver from a flying object of the arc extinguishing device is attached to the latch receiver. 2. The circuit breaker according to claim 1, wherein the protection cover is provided with a reset spring receiving portion mounted between the latch receiver and the trip crossbar.