JP3147181B2 - Movable contact device for circuit breakers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable contact device used for a circuit breaker for a wiring or an earth leakage breaker, and more particularly to a movable contact device suitable for a circuit breaker having a medium capacity or more.

[0002]

2. Description of the Related Art A movable contact in the above-mentioned circuit breaker is generally rotatably supported by a case via an opening / closing shaft made of an insulating material.
The other end is movably connected to a connection conductor fixed to the case. The movable contact conductor is usually formed of a flat plate conductor. In this case, in a small capacity circuit breaker, the flat conductor is used in a direction in which the cross section is vertically long, that is, in a direction in which the plate thickness is in the width direction.

A movable contact conductor having a vertically long cross section is reasonable because it has a high mechanical strength in the switching direction and requires a small space in the width direction of the circuit breaker. Therefore, there is a problem that the current carrying capacity is restricted due to only the thickness of the plate being obtained. Therefore, in a circuit breaker having a medium size or larger, for example, a 225A frame or larger, the movable contact conductor is configured to have a horizontally long cross section, and the movable contact is joined to a flat surface of the flat plate conductor.

FIGS. 3 and 4 show such a conventional movable contact device . FIG. 3 is a perspective view showing three phases collectively, and FIG. 4 is an enlarged longitudinal sectional view of one phase among them. is there. Figure 3 and
Oite the beauty Figure 4, the movable contact conductor 1 which is press-formed from copper strip is fixed by caulking at around two places to the support bracket 2 made of steel plate side walls on both sides formed by bending, the support bracket 2 is also It is rotatably supported by a pin 4 on a forked holder 3 made of a steel plate. The holder 3 is fitted into an opening / closing shaft 5 of an insulator extending over each phase, and both legs are fixed by U-shaped fittings 6 caulked to this.

[0005] A movable contact 7 is joined to a front portion of the lower surface of the movable contact conductor 1, and a lead wire 8 made of a braided copper wire is attached to a rear end.
Are joined at one end. The other end of the lead wire 8 is joined to a connection conductor (not shown) fixed to the case of the circuit breaker, and this connection conductor is further connected to a conductor of an overcurrent trip device (not shown). A contact spring 9 made of a tension spring is stretched between the support fitting 2 and the holder 3.

[0006]

However, such a conventional configuration has the following problems. (1) As described above, the flat conductor constituting the movable contactor conductor 1 is used in a laterally long cross section, so that a large space is required in the width direction, and it is difficult to downsize the circuit breaker. (2) supplement the mechanical strength of the movable contact conductor 1 in the thickness direction,
Further, since the support fitting 2 is required to pass the pin 4, the structure becomes complicated. (3) The movable contact conductor 1 is connected to a connection conductor (not shown) via a lead wire 8. The lead wire 8 has a certain degree of rigidity, and this rigidity changes depending on the bent state of the lead wire 8. Therefore, the contact pressure and the switching speed between the movable contact 7 and the fixed contact (not shown) are likely to vary. (4) The lead wire 8 may be broken due to fatigue due to repetitive bending caused by the opening and closing movements of the movable contactor. The required space increases. The present invention solves such a problem, requires less space, has a simple structure,
It is another object of the present invention to provide a movable contact device of a circuit breaker that does not require the use of a lead wire.

[0007]

According to the present invention, two flat plate conductors having a vertically long cross section are arranged in parallel on the left and right sides to form a movable contact conductor for one phase, and a movable contact is provided at one end thereof. The connecting conductor fixed at the end to the case of the circuit breaker is slidably sandwiched between the flat conductors, and the connecting conductor is fixed by a spring.
The flat conductor is pressed against the connection conductor, and the connection conductor is further pressed.
The object is achieved by inserting a compression spring between the plate conductors near the body .

[0008]

A two-plate conductor is arranged in parallel with a vertical cross section to form a one-phase movable contact conductor. Thus, as in the case of the small capacity circuit breaker, the dimension in the width direction can be reduced, a large mechanical strength can be obtained in the opening and closing direction, and a wide joint surface of the movable contact can be obtained. At that time,
Since the connecting conductor is sandwiched between two flat conductors, and these are pressed from both sides by springs to electrically connect the two by sliding contact, no lead wire is required.

In this case, current flows in the same direction in the two flat conductors arranged in parallel. Therefore, an electromagnetic attraction force is generated between these currents, and the flat conductor is pressed against the connection conductor to obtain a good contact state. However, when the short-circuit current is interrupted, the electromagnetic attraction force becomes excessive, and there is a possibility that galling may occur on the sliding contact surface. Therefore, by inserting a compression spring between the plate conductors near the connection conductor, the spring force reduces the electromagnetic attraction force, thereby preventing the occurrence of unnecessary contact pressure between the plate conductor and the connection conductor. be able to.

[0010]

EXAMPLES Hereinafter, the embodiment of the present invention will be described with reference to FIGS. Note that the same reference numerals are used for the portions corresponding to the conventional example. Here, FIG. 1 is a plan view showing three phases collectively, and FIG. 2 is a cross-sectional view taken along the line II-II. In FIGS. 1 and 2, the movable contact conductor 1 of each phase is composed of two left and right flat plate conductors 1A and 1B having a vertically long cross section arranged in parallel. Movable contacts 7A and 7B are respectively joined to the lower surfaces of the plate conductors 1A and 1B by brazing. Reference numeral 10 denotes a fixed contact that contacts the movable contacts 7A and 7B in common, and 11 denotes a fixed contact conductor to which the fixed contact 10 is joined.

Reference numeral 12 denotes a connecting conductor made of a plate material, which comprises an L-shaped supporting member 12a and an L-shaped connecting piece 12b joined to the front surface thereof. The movable contact conductor 1 sandwiches the connection piece 12b at the other end of the plate conductors 1A and 1B, and is electrically connected thereto. 4 is a flat conductor 1
The movable contact conductor 1 is supported by the holder 3 with pins penetrating through the A and 1B and the connection piece 12b, and the movable contact conductor 1 rotates about the pin 4 and slides on the connection piece 12b. Numeral 13 denotes compression springs inserted between the movable contact conductor 1 and the holder 3 on both sides of the movable contact conductor 1 and are mounted on the pins 4 to press the flat conductors 1A and 1B against the connecting piece 12b, and to provide a necessary contact pressure therebetween. Generate.

The holder 3 is made of a molding resin.
It is formed integrally with an opening / closing shaft 5 that connects the holders 3 of each phase to each other. The opening / closing shaft 5 is supported by a bearing groove provided on a phase gap wall of a case (not shown), and the holder 3 rotates around the opening / closing shaft 5. 9 is a contact spring composed of a compression spring. In this case, a spring support 14 fixed to the case of the circuit breaker is used.
And the end of the movable contact conductor 1
The movable contact conductor 1 is biased counterclockwise in FIG. 2 around the pin 4 to press the movable contacts 7A and 7B against the fixed contact 10,
The necessary contact pressure is created between them.

In the above configuration, a current flows from the fixed contact conductor 11 to the movable contact conductor 1 via the fixed contact 10 and the movable contacts 7A and 7B, and further flows to the connection conductor 12 which is in sliding contact therewith. As indicated by the arrows in FIG. 1, current flows in the parallel plate conductors 1A and 1B in the same direction, so that an electromagnetic attraction acts between these currents, and the plate conductors 1A and 1B are subjected to the electromagnetic attraction. Thereby, it is pressed against the connection piece 12b, and the contact pressure is increased. At the time of opening operation of the circuit breaker, the holder 3 connected to the toggle link of the opening / closing mechanism (not shown) is driven clockwise in FIG. 2, and the movable contact conductor 1 is pulled up accordingly. At this time, the flat conductors 1A and 1B slide with respect to the connection piece 12b while being pressed by the compression spring 13.

According to the illustrated embodiment, the flat conductors 1A, 1B
, The movable contact conductor 1 is configured as a vertically long section, so that the space in the width direction is small, the mechanical strength in the opening and closing directions is high, and the pins 4 can be directly inserted into the plate conductors 1A and 1B. Thus, the conventional support 2 (FIG. 4) is not required. Further, the flat conductors 1A, 1B
Are arranged in parallel, so that even in a circuit breaker having a medium capacity or more, a sufficient space for joining the movable contacts 7A and 7B and a current-carrying area of the movable contact conductor 1 can be obtained, and heat radiation is good. Becomes The movable contacts 7A and 7B may be provided integrally so as to straddle the flat conductors 1A and 1B.
As shown in the drawing, the contact state with the fixed contact 10 is improved by providing the flat conductors 1A and 1B separately. Further, since the connecting conductor 12 is sandwiched between the two flat conductors 1A and 1B and electrically connected to each other by sliding contact, the conventional lead wire 8 (FIG. 4) becomes unnecessary, and the contact pressure varies and the disconnection occurs. The danger of is eliminated.

1 and 2, the connecting conductor 1
2, a compression spring 16 is inserted between the plate conductors 1A and 1B. The compression spring 16 is composed of flat conductors 1A and 1B.
The pin 17 is fitted over the pin 17 and a ring 18 for retaining is fitted on both ends of the pin 17. According to such a configuration, the electromagnetic attraction force acting between the flat plate conductors 1A and 1B is reduced by the compression spring 16, and galling of the sliding contact surface due to excessive electromagnetic attraction force is prevented.

[0016]

According to the present invention, a movable contact conductor is formed by arranging two flat plate conductors having a vertically long cross section in parallel on the left and right.
The connecting conductor is slidably sandwiched between the flat conductors and pressed by a spring, so that the space in the width direction can be reduced and the circuit breaker can be downsized, and the support bracket between the movable contact conductor and the holder Is unnecessary, the structure is simplified, and furthermore, a lead wire between the movable contact conductor and the connection conductor is not required, so that the opening / closing operation is stabilized and there is no fear of disconnection. Also connect
The insertion of a compression spring between the flat conductors near the conductor
Of the sliding contact surface due to excessive electromagnetic attraction between the flat conductors.
Galling can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a perspective view of a conventional example.

FIG. 4 is an enlarged vertical sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Movable contact conductor 1A Plate conductor 1B Plate conductor 7A Movable contact 7B Movable contact 12 Connection conductor 16 Compression spring 19 Projection

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-23429 (JP, A) JP-A 62-48723 (JP, U) JP-A 13-12778 (JP, Y1) JP-A 18- 10889 (JP, Y1) Jiko 35-11949 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01H 73/02

Claims (1)

(57) [Claims] 1. A movable contact conductor for one phase is constituted by arranging two flat plate conductors having a vertically long cross section in the left and right directions, and a movable contact is provided at one end thereof, and a movable contact conductor is provided at the other end thereof to a circuit breaker case. The fixed connection conductor is slidably sandwiched between the flat conductors , and the flat conductor is pressed against the connection conductor by a spring.
And compressed between the plate conductors near the connection conductor.
A movable contact device for a circuit breaker, wherein a spring is inserted .