JPH03205733A - Circuit breaker - Google Patents

Abstract

PURPOSE:To shrink the storage space of a lead wire and obtain the stable switching performance by locating a lead wire connection section on one side of a moving contact, and connecting the lead wire connection section and the moving contact with the U-shaped lead wire. CONSTITUTION:The lead wire connection section 8a of a connecting plate 8 is folded and erected from one side of a base section 8b screwed to a case 1, and the connecting plate 8 is arranged near a moving contact 4 so that the lead wire connection section 8a is located in parallel on its side. A lead wire 7 is formed into a U-shape, and both ends are welded to the moving contact 4 and the lead wire connection section 8a of the connecting plate 8 respectively. The insertion interval of the lead wire connection section 7 is rarely required in the longitudinal direction, and the longitudinal storage space of the lead wire 7 provided on the case 1 is made very little. The longitudinal storage space of the lead wire 7 is made about a half, the deformation resistance applied from the lead wire 7 is made small, the switching speed is stabilized, and the cutoff performance is improved.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a small circuit breaker such as a molded case circuit breaker or an earth leakage breaker, and more particularly to a structure for electrically connecting a movable contact that moves to open and close to a fixed connection plate.

[Conventional technology]

In the above circuit breaker, there is a movable contact that opens and closes with respect to a fixed contact fixed to the case, and a movable contact that is fixed to the case on the opposite side of the fixed contact across the movable contact and connected to the overcurrent detection section. The connected connection plate is generally connected with a flexible lead wire. Twisted wires made of thin copper wires are used as lead wires. In that case, for example, as described in Japanese Utility Model Application No. 57-194237, the lead wire connection portion of the connection plate is arranged on the longitudinal line of the movable contact, and both ends are connected to the movable contact and the lead of the connection plate, respectively. The lead wires joined to the wire connections are also typically placed on the same line.

[Problem to be solved by the invention]

Such a lead wire moves and deforms with the opening and closing movements of the movable contact, exerts a resistance force on the movable contact, and is repeatedly subjected to bending loads. This resistance affects the opening/closing speed of the movable contact, and large deformation of the lead wire may lead to breakage due to fatigue. Therefore, it is necessary to give the lead wire as much slack as possible to improve its flexibility, and also to provide a space for accommodating the lead wire so as not to impede its movement or deformation. However, in conventional circuit breakers, movable contacts,
Since the lead wires and the lead wire connection portions of the connection plate are arranged in tandem, attempting to provide the above margin increases the length of the case, making it difficult to downsize the circuit breaker. If the longitudinal dimension is forcibly reduced, the force that deforms the lead wire during opening and closing operations becomes excessive, and the force of the closing spring of the opening and closing mechanism may not be able to overcome this force, resulting in a closing failure. Therefore, the present invention has devised a lead wire connection structure to reduce the lead wire housing space, and at the same time reduce the resistance to the movable contact so as to achieve stable switching performance. The purpose is to provide equipment.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a movable contact that opens and closes with respect to a fixed contact fixed to a case, and a connecting plate fixed to the case, which is connected to a flexible lead wire to conduct electricity. In a circuit breaker that is connected to a circuit breaker, the lead wire connection portion of the connection plate is located on the side of the movable contact, and the lead wire connection portion and the movable contact are connected by making the lead wire into a U-shape. shall be taken as a thing.

[For use]

Since the lead wire connection portion of the connection plate is located on the side of the movable contact, there is almost no need for a longitudinal spacing between the movable contact and the connection plate. Further, since the deformation of the lead wire due to the opening/closing movement of the movable contactor results in torsional deformation, the resistance is lower than that of bending deformation, and furthermore, the amount of vertical movement of the lead wire is also reduced.

【Example】

FIG. 1 shows an embodiment of a three-pole circuit breaker according to the present invention, and the figure is a longitudinal sectional view of the central pole portion in a closed circuit state. Further, FIG. 2 is a plan view of the movable contact portion, and FIG. 3 is a longitudinal sectional view of the movable contact portion in an open state. In FIG. 1, l is a molded resin case, 2 is also a cover, 3 is a fixed contact that is tightened to the case 1 with a screw (not shown) and is equipped with a fixed contact 3a, and 4 is a movable contact 4a.
5 is a resin holder that holds the movable contact 4 via a shaft 6, 7 is a lead wire whose one end is welded to the movable contact 4, and 8 is attached to the case l with a screw (not shown). The connection plate 9 is tightened and the other end of the lead wire 7 is welded to the lead wire connection part 8a, and the connection plate 9 is made up of a heater conductor 9a and a bimetal 9b welded to this, and is connected at the L-bent base of the heater conductor 9a. Overcurrent detection unit connected to plate 8, 1
0 is a terminal plate on the load side welded to the heater conductor 9a. The connection plate 8 and the heater conductor 9a may be integrally formed. In the illustrated closed circuit state, current flows from the fixed contact 3 that also serves as a terminal board on the power supply side, through the fixed contact 3a, the movable contact 4a, the movable contact 4, the lead wire 7, the connection plate 8, and the heater conductor 9a to the terminal plate 10. flows to The holder 5 has an opening/closing shaft 11 whose cross-sectional shape is shown by a broken line in FIG.
The respective poles are integrally connected and rotatably supported by the case 1 via this opening/closing shaft 11. Although not shown,
A contact spring that biases the movable contact 4 toward the fixed contact 3 is inserted between the holder 5 and the movable contact 4, and applies contact pressure between the contacts 3a and 4a. Reference numeral 12 denotes an operating handle for opening and closing operations.Although not explained in detail, an opening/closing mechanism 13 is provided between the operating handle 12 and the holder 5. When the opening operation is performed, the holder 5 rotates clockwise in the figure around the opening/closing shaft 11, and the movable contact 4 is rotated as shown in FIG.
to separate. Furthermore, when an overload current flows through the circuit breaker, the bimetal 9b bends to the left in the figure due to the heat generated by the heater conductor 9a, tripping the tripping mechanism 14 and separating the movable contact. To close the separated movable contact 4 again, after opening, simply close the operating handle 12 to the left in the figure, and when tripping, reset the tripping mechanism 14 and then close again. Close the operating handle 12. Now, in the illustrated circuit breaker, the connection plate 8 is connected to the case 1.
The lead wire connection portion 8 is screwed from one side of the base 8b to the
This connection plate 8 is placed in close proximity to the movable contact 4 such that the lead wire connection portion 8a is located parallel to the side thereof. The lead wire 7 has a U-shape, and both ends are welded to the movable contact 4 and the lead wire connection portion 8a of the connection plate 8, respectively, as described above. According to such a structure, the lead wire 7 is given slack in the lateral direction between the movable contactor 4 and the lead wire connecting portion 8a,
Since almost no insertion interval between the lead wire connection parts 7 is required in the longitudinal direction, the lead wires 7 to be provided in the case 1 are
The storage space in the longitudinal direction becomes small. Further, since the deformation of the lead wire 7 due to the opening/closing movement of the movable contactor 4 is torsional deformation, the deformation is easier than conventional bending deformation. Therefore, there is no need to allow the lead wire 7 as much slack as in the conventional case, and it can be housed in a case with the same lateral dimension as the conventional case. Since there is almost no vertical movement, the space around the lead wire 7 can also be made smaller than before. Furthermore, the torsional deformation has a smaller resistance force than the bending deformation, and its fluctuation is also smaller, so the movable contact 4 can be operated with a smaller force than before, and variations in opening/closing speed are also reduced. FIG. 4 is a plan view of a movable contact portion showing another embodiment,
In this case, the lead wire connection portions 8a are raised on both sides of the connection plate 8, and the two lead wires 7 are connected as a pair. This makes it possible to handle circuit breakers with large rated currents, and also allows the lead wire 7 to be made thinner for each lead wire 7 if the rated current is the same.

【Effect of the invention】

According to this invention, there is almost no need for a lead wire insertion interval in the longitudinal direction between the movable contactor and the connection plate, and the space for accommodating the lead wires in the longitudinal direction is approximately half that of the conventional one. At the same time, the deformation resistance that the movable contact receives from the lead wire during the opening/closing operation is reduced, the opening/closing speed is stabilized, and the breaking performance is improved.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view of the center pole portion of the circuit breaker in the closed state, Fig. 2 is a plan view of its movable contact portion, and Fig. 3 is the same as in Fig. 1. FIG. 4 is a side view of the movable contact portion in an open state, and FIG. 4 is a plan view of the movable contact portion of another embodiment. ■...Case, 3...Fixed contact, 4...Movable contact, 7...Lead wire, 8...Connection plate, 8a is lead wire connection part.

Claims (1)

[Claims] 1) In a circuit breaker in which a movable contact that opens and closes with respect to a fixed contact fixed to a case and a connection plate fixed to the case are electrically connected by a flexible lead wire, the connection A circuit breaker characterized in that a lead wire connecting portion of a plate is located on a side of a movable contact, and the lead wire connecting portion and the movable contact are connected with the lead wire in a U-shape.