JP2001332162A - Movable contact for circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a useful movable contact for improving the breaking performance and relability of a circuit breaker by eliminating poor strength of the movable contact to be used in combination with an arc-extinguishing chamber having a smaller inner width. SOLUTION: A fixed contact for the circuit breaker is formed in sheet metal construction by putting an end 4a of the contact having the movable contact 5 in the arc-extinguishing chamber 9 in the state of facing a contact point 3 of the fixed contact 2 in a contact/separation movable manner and connecting an arm portion 4b, to linked to a closing spring 10, at the other end to a lever of a switching handle 8. A reinforcing plate 12 is integrally joined to the end of the contact to be reinforced for improving bending rigidity. Thus, the inner width of the arc-extinguishing chamber is decreased for improving breaking performance, the lowering of strength due to the decreased width at the end of the movable contact is prevented, and the deformation of the movable contact due to impact force during inputting the breaker is inhibited, assuring mechanical strength necessary for a required contact pressure between the fixed and movable contacts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a circuit breaker for wiring,
The present invention relates to a movable contact of a circuit breaker for an earth leakage breaker and the like.

[0002]

2. Description of the Related Art First, FIG. 4 shows an overall configuration of a circuit breaker described above, and FIG. 5 shows a conventional structure of a movable contact incorporated in the circuit breaker. 4 (a) and 4 (b), 1 is a resin case, 2 is a fixed contact, 3 is a fixed contact, 4 is a movable contact, 5 is a movable contact, and 6 is a flexible lead connected to the movable contact 4. Line, 7 is an overcurrent detection device, 8 is an open / close handle,
8a is a handle lever, 9 is an arc-extinguishing chamber having a U-shaped cross section formed on the bottom side of the case 1 corresponding to the fixed contact 3 and the movable contact 5 of each pole individually, and 9a is a moving path of the movable contact 4. An arc-extinguishing grid plate attached along the arc-extinguishing chamber, 10 is an opening / closing spring of a contact opening / closing mechanism, 11 is a latch, and the movable contact 4 inserts the tip to which the movable contact 5 is fixed into the arc-extinguishing chamber 9. The fixed contact 2 is opposed to the fixed contact 3 and the upper end of the contact is pivotally connected to the handle lever 8a in a swingable manner. The opening / closing spring (tensile coil spring) 10 is stretched between the movable contact 4 and the latch 11.

Here, the movable contact 4 is a sheet metal processed product obtained by pressing and bending a copper plate. As shown in FIGS. 5 (a) to 5 (c), the movable contact 4 is connected to the tip 4a to which the movable contact 5 is fixed. It has a bifurcated arm portion 4b extending upward, and a shaft portion 4b-1 connected to the handle lever 8a of the opening / closing handle 8 protrudes laterally from the upper end of the arm portion 4b. Arm 4c from the lower end of 4b behind tip 4a
Is extended, and the lower end hook of the opening / closing spring 10 is hooked here. In the assembled state shown in FIG. 4, the tip 4a of the movable contact 4 to which the movable contact 5 is fixed enters the arc-extinguishing chamber 9 and faces the fixed contact 2 so as to be able to contact and separate therefrom. The width of the tip 4a is set to a size corresponding to the inner width of the arc-extinguishing chamber 9.

The opening and closing operation of such a circuit breaker is well known. When the circuit breaker is turned on in FIG.
The movable contact 4 is pressed against the fixed contact 2 by the spring force described above to apply a predetermined contact pressure between the fixed contact 3 and the movable contact 5. Here, the opening / closing handle 8 is turned from ON to OF.
When moving to the F position, the movable contact 4
Receives the spring force of the open / close spring 10 and reverses to the right.
The movable contact 4 is separated from the fixed contact 2. Also, when an abnormal current flows in the main circuit in the energized state, the overcurrent detection device 7
Operates to release the latch 11 of the opening / closing mechanism, and the upper fulcrum of the opening / closing spring 10 moves to the right side of the upper fulcrum of the movable contact 4 following this, and drives the movable contact 4 to the opening position. And trip the circuit breaker.

[0005]

The conventional circuit breaker incorporating the above-mentioned movable contact 4 having a sheet metal structure has the following problems to be solved. That is,
In order to enhance the breaking performance of the circuit breaker, it is necessary to extinguish the arc generated between the fixed contact 3 and the movable contact 5 at the time of current interruption, and for that purpose, the arc extinguishing chamber 9 is required.
The movable contact 5 of the movable contact 4 moving inside the arc-extinguishing chamber is inserted deep into the arc-extinguishing chamber. It is effective to increase the cooling effect by touching the inside of the arc extinguishing chamber 9, but if the inner width of the arc extinguishing chamber 9 is reduced, the width of the tip 4a of the movable contact 4 moving in the arc extinguishing chamber must necessarily be reduced. is there.

On the other hand, the movable contact 4 sufficiently withstands an impact force applied when the circuit breaker is turned on, and has a mechanical strength necessary to secure a predetermined contact pressure between the fixed / movable contact in the ON state. It is. On the other hand, the movable contact used for a circuit breaker for wiring and the like is a small component, and the movable contact (made of copper) 4 having a sheet metal structure shown in FIG. 5 has a relatively small plate thickness. If the width of the distal end portion 4a is smaller than the current state, the bending rigidity is reduced and the contact distal end portion is deformed by the impact force applied when the circuit breaker is turned on due to insufficient strength. Therefore, there is a possibility that the required contact pressure cannot be ensured and thus cannot be achieved.

For this reason, in a circuit breaker such as a wiring breaker employing a movable contact having a conventional structure, the inner width of the arc-extinguishing chamber and the width of the tip of the contact are required to improve the breaking performance. It is difficult to narrow down than the product. The present invention has been made in view of the above points, and an object of the present invention is to improve the breaking performance and reliability by eliminating insufficient strength of a movable contact used in combination with an arc-extinguishing chamber having a narrow inner width. It is another object of the present invention to provide an improved movable contact of a circuit breaker.

[0008]

According to the present invention, in order to achieve the above object, according to the present invention, a contact tip provided with a movable contact can be brought into and out of contact with a fixed contact by placing the tip of the contact in an arc-extinguishing chamber. In the movable contact of the circuit breaker, the arm of the other end is connected to the lever of the opening / closing handle and connected to the opening / closing spring of the contact opening / closing mechanism. A reinforcing plate is attached to the back side of the part and they are integrally connected, and the insufficient strength due to the narrowing of the tip of the movable contact according to the reduction of the inner width of the arc extinction chamber is reinforced with the reinforcing plate. (Claim 1). Further, a connecting arm portion of an opening / closing spring can be formed on the reinforcing plate using the reinforcing plate (claim 2).

(2) In the second aspect of the present invention, the distal end portion of the contact is double-folded to increase its bending rigidity, and the movable contact is fixed to the front surface of the folded portion (claim 3). (3) In the third invention, the movable contact is divided into two parts, a contact tip to which the movable contact is fixed, and an arm, and the contact tip is made of a tough part (for example, by increasing the thickness of the plate and increasing its cross section. (Increase the coefficient), and then connect it to the arm of the sheet metal structure and assemble it (claim 4).

The inner width of the arc-extinguishing chamber is narrowed for the purpose of improving the breaking performance of the circuit breaker by reinforcing the tip of the movable contact by means as described in the above items. Even if the width of the tip is reduced, the mechanical strength required to obtain the required contact pressure between the fixed / movable contacts in the closed state can be secured without being deformed by the impact force when the circuit breaker is closed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on illustrated embodiments. In each of the embodiments, FIG.
Are given the same reference numerals, and detailed description thereof will be omitted. Embodiment 1 FIGS. 1A to 1D show an embodiment corresponding to claims 1 and 2 of the present invention. In this embodiment, the shape of the movable contact 4 is basically the same as the movable contact having the sheet metal structure shown in FIG. 5, but the reinforcing plate 12 is overlapped on the back side of the contact tip 4a. The two are integrally joined by brazing, caulking, or the like to reinforce the distal end portion 4a of the movable contact 4 to increase the bending rigidity.
The material of the reinforcing plate 12 is preferably a high-rigidity, non-magnetic stainless steel or the like, but may be a magnetic material such as a steel plate.

Further, the reinforcing plate 12 of the illustrated embodiment has an arm 1 whose upper end is bent in an L-shape and protrudes toward the back side of the contact.
2a is formed, and a hook of the opening / closing spring 10 is hooked on the arm portion 12a. As described above, the arc extinguishing chamber 9
The movable contact 4 having a sheet metal structure incorporated in the circuit breaker in combination with the above structure has a structure in which the contact tip 4a is reinforced by the reinforcing plate 12, so that the inner width of the arc-extinguishing chamber 9 is improved in order to enhance the breaking performance. Even if the width of the tip 4a of the movable contact 4 is reduced in accordance with this, it is possible to ensure the strength that the movable contact 4 is not unduly deformed by the impact force when the breaker is turned on. it can.

[Embodiment 2] FIG. 2 shows an embodiment corresponding to claim 3 of the present invention. In this embodiment, with respect to the movable contact 4 having a sheet metal structure, a tip portion 4a extending downward from an arm portion 4b is folded back and overlapped as shown in the drawing, and a movable contact 5 is provided on the front surface of the folded portion.
Is fixed.

According to this structure, the bending rigidity of the contact tip 4a is increased as compared with the conventional structure shown in FIG. Therefore, as in the first embodiment, even if the width of the distal end portion 4a is reduced, it is possible to ensure the strength that the movable contactor 4 is not deformed by the impact force when the breaker is turned on, and it is possible to ensure the contact. The cross-sectional area of the tip 4a is twice as large as that of the prior art, so that the heat generation due to current flow can be reduced.

[Embodiment 3] FIG. 3 shows an embodiment corresponding to claim 4 of the present invention. In this embodiment, the movable contact 4 is composed of two parts, a contact tip 4a and an arm 4b having a sheet metal structure. Here, the contact tip 4a has a thickness t so as to have a large section modulus, for example. It is a tough part made of thick copper material, and its upper end is integrally joined to the front end face of the forked arm portion 4b by brazing, caulking or the like. With such a configuration, the bending rigidity of the distal end portion 4a of the movable contact 4 is greatly enhanced as compared with the conventional structure of FIG. 5, so that the same effects as those of the above-described embodiments can be obtained.

[0016]

As described above, according to the present invention, a movable contact incorporated in a circuit breaker in combination with an arc-extinguishing chamber for wiring breakers, earth leakage breakers, and the like.
2. The mechanical strength of a contact tip provided with a movable contact is determined.
Alternatively, the inner width of the arc-extinguishing chamber is reduced by strengthening by means of 3 and 4, and the width of the tip of the movable contact is reduced accordingly. The strength that prevents the movable contact from being unduly deformed by the impact force at the time can be ensured, thereby greatly contributing to improvement in the breaking performance and reliability of the circuit breaker.

[Brief description of the drawings]

FIGS. 1A and 1B are configuration diagrams of a movable contact corresponding to a first embodiment of the present invention, wherein FIG. 1A is an assembly configuration diagram of a circuit breaker incorporating a movable contact, and FIG. Sectional view showing the positional relationship between the arc chamber and the movable contact, (c) and (d) are external perspective views of the movable contact as seen from the front and back sides, respectively.

FIG. 2 is an external perspective view of a movable contact corresponding to a second embodiment of the present invention.

FIG. 3 is an external perspective view of a movable contact corresponding to a third embodiment of the present invention.

4A and 4B are assembly configuration diagrams of a circuit breaker incorporating a movable contact having a conventional structure, wherein FIG. 4A is a longitudinal side view, and FIG.
Sectional view showing the positional relationship between the arc extinguishing chamber and the movable contact in the figure.

FIG. 5 is a structural view of a movable contact in FIG. 4;
Is the external perspective view, (b) and (c) are the side and rear views of the movable contact in combination with the open / close spring, respectively.

[Explanation of symbols]

 2 Fixed contact 3 Fixed contact 4 Movable contact 4a Contact tip 4b Arm 5 Movable contact 8 Open / close handle 9 Arc extinguishing chamber 10 Open / close spring 12 Reinforcement plate 12a Arm for opening / closing spring

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Zenkichi Hasegawa 1-1, Tanabe Nitta, Kawasaki, Kawasaki, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Yoshiaki Kawashima 1, Tanabe Nitta, Kawasaki, Kawasaki, Kanagawa, Japan No. 1 Inside Fuji Electric Co., Ltd. (72) Inventor Tadahisa Aoki 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term inside Fuji Electric Co., Ltd. 5G030 AA06 XX08 5G051 FA01 FA03

Claims (4)

[Claims] An end of a contact provided with a movable contact is inserted into an arc-extinguishing chamber so as to face the contact of a fixed contact so as to be able to come and go, and an arm on the other end is connected to a lever of an opening / closing handle. A circuit breaker, wherein a movable contact of a circuit breaker, which is a sheet metal processed product connected to an opening / closing spring of a contact opening / closing mechanism, is integrally connected with a reinforcing plate attached to the back side of the contact tip. The movable contact of the vessel. 2. The movable contact according to claim 1, wherein a connecting arm of an opening / closing spring is formed on the reinforcing plate. 3. A contact tip provided with a movable contact is inserted into an arc-extinguishing chamber to face the contact of a fixed contact so as to be able to contact and separate, and an arm on the other end is connected to a lever of an opening / closing handle. A circuit breaker, which is a sheet metal processed product connected to an opening / closing spring of a contact opening / closing mechanism. Movable contact. 4. A contact tip provided with a movable contact is inserted into an arc-extinguishing chamber to face the contact of the movable contact so as to be able to contact and separate, and an arm on the other end is connected to a lever of an opening / closing handle. In the movable contact of the circuit breaker connected to the opening / closing spring of the contact opening / closing mechanism, the movable contact is divided into two parts, the contact tip to which the movable contact is fixed and the arm, and the contact tip is tough. A movable contact of a circuit breaker, which is connected to an arm as a part.