JP2530688Y2 - Circuit breaker for wiring breaker - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention belongs] This invention relates to overcurrent response elements such as a direct heat type bimetal that generates when a large current such as a short-circuit current of a relatively small circuit breaker is cut off, and an electric circuit configuration. The present invention relates to a commutation device for reducing thermal stress of a member.

[Conventional technology and its problems]

Generally, when a large current, such as a short-circuit current, flows into a small circuit breaker, this large current is instantaneously tripped to the contacts in the circuit components, the flexible conductor, and the directly heated bimetal of the overcurrent trip device. The flow will continue until the shut-off is completed. Therefore, a circuit breaker that requires a large breaking capacity must be able to withstand the large thermal stress caused by this large current, and for that purpose, in particular, the fixed contact, movable contact, movable contact There is a choice between increasing the heat capacity of the flexible conductor and the direct heat type bimetal connected to the element, or giving up the direct heat type bimetal method, both of which are adopted because the product becomes larger and the cost increases. The fact was not.

A circuit breaker provided with a commutation device, an example of which is shown in FIG. 9, is known as a device devised from the above. In the figure, an insulating case 1 has an opening / closing mechanism 3 for opening and closing an electric circuit component 2 and a contact portion thereof, and detects an overcurrent in the electric circuit component 2 and detects the overcurrent and connects the electric circuit component 2 via the opening / closing mechanism 3. An overcurrent trip device 4 that performs a breaking operation and a commutation device 5 that bypasses the overcurrent trip device 4 from the middle of the electric circuit configuration unit are housed. The electric circuit forming unit 2 includes a power supply terminal 11, a fixed contact 12 extended from the power supply terminal 11, and a movable contact connected to the opening / closing mechanism 3 so as to be able to contact and separate from the fixed contact 12.
13 and a flexible conductor having one end connected to the movable contact 13 and the other end connected to the free end of the bimetal 31 of the overcurrent trip device 4.
14, a load-side terminal 15 that is overlapped and connected to the fixed-side connection end of the bimetal 31, an arc-extinguishing chamber 16 surrounding a contact portion between the fixed contact 12a of the fixed contact 12 and the movable contact 13a of the movable contact 13. A contact spring 17 supported by the opening / closing mechanism 3 and applying a contact pressure to the movable contact 13; The opening / closing mechanism 3 is rotatably supported by the insulating case 1 and the side plate 21 and has a connecting rod 22.
An operating handle 23 connected to the movable contact 13 via
A latch 24 which engages with the movable contact 13 via the connecting rod 22 to support the contact spring 17 and engages with the instantaneous tripping movable piece 32 of the overcurrent tripping device 4, a latch 24 and an operation handle 23 And an opening / closing spring 25 stretched between them. The overcurrent trip device 4 is arranged so as to surround the bimetal 31 and the movable piece 32 and the bimetal 31, and when the large current such as the short-circuit current flows through the bimetal 31, the movable piece 32 is attracted.
An iron core 33 that is disengaged from the latch 24 to perform a breaking operation, a return spring 34 elastically mounted between the free end of the movable piece 32 and the inner wall of the insulating case 1, and fitted into a recess of the insulating case 1. The adjusting screw 35 is screwed into the screw hole plate 6, the tip of which abuts on the connection end between the bimetal 31 and the load-side terminal 15 to change the tripping operation current of the bimetal 31 by twisting. The commutation device 4 has a flexible conductor between one of the arc-extinguishing grids 16a constituting the arc-extinguishing chamber 16 and one of the arc-extinguishing grids 16a located on the separation side of the movable contact 13 and the load-side terminal 15. It is provided so as to bypass 14 and the bimetal 31, and is composed of an insulated wire 41 and a terminal 42 connected to both ends thereof, and a screw 43 connecting the terminal 42 to the arc-extinguishing grid 16a and the load-side terminal 15. ing.

In the above configuration, when an overcurrent flows through the circuit breaker for wiring, the bimetal 31 is bent by heat generation, or the movable piece 32 is attracted by the iron core 33, whereby the engagement between the movable piece 32 and the latch 24 is released, The latch 24 is rotated by the open / close spring 25, and the movable contact
13 is separated from the fixed contact 12, that is, cuts off. When the breaking operation is performed, an arc is generated between the movable contact 13a and the fixed contact 12a, and when the movable contact 13 approaches the arc-extinguishing grid 16a at the separation position, the arc from the movable contact 13 is extinguished. It is commutated to the commutation device 5 via the arc grid 16a, and the arc extinguishing chamber 1
The arc energy in 6 becomes small and the arc quenching is accelerated. This is the same even when the breaking current is a large current such as a short-circuit current, and as a result, the fixed contacts 12a,
The movable contact 13a, the flexible conductor 14, and the bimetal 31 are protected from thermal stress without increasing the heat capacity. However, the commutation device 5 has a large number of parts because the insulated wire 41 is laid in a narrow space without interfering with the operation of the opening / closing mechanism 3 or the terminals 42 are connected to both ends and the screws 43 are connected by screwing. In addition, there is a disadvantage that the assembly and connection work is troublesome and takes much longer time than expected, so that the high cost cannot be solved.

[Purpose of the invention]

It is an object of the present invention to provide a commutation device for a circuit breaker for wiring, which eliminates the above-mentioned disadvantages of the related art and eliminates connection by screwing or the like without increasing the size and making assembly easy and costly. is there.

[Points of the invention]

The point of this invention is to achieve the above-mentioned purpose,
A side plate made of a metal plate provided in an insulating case is provided for supporting an opening / closing mechanism for controlling the movable contact to and from the fixed contact, and a part of the side plate on the arc extinguishing chamber side is extinguished. A commutation plate formed extending to the position of the arc-extinguishing grid in the arc chamber is arranged on the side plate side of the arc-extinguishing grid, connected to the load-side terminal, and has a tip extended to near the upper end of the side plate. The side plate reverse flow plate side is connected to the tip of the connection piece, the fixed end of the overcurrent response element is connected to the tip of the connection piece, the movable end of the overcurrent response element is connected to the It is connected to a movable contact, and consists only of deformation and connection of an essential member.

[Example of the invention]

1 and 2 are views showing an embodiment of a commutation device of a circuit breaker for wiring according to the present invention, wherein FIG. 1 is a longitudinal sectional view at the time of closing, and FIG. 2 shows a separating operation process. It is principal part sectional drawing.
In the figure, the same parts as those of the conventional type shown in FIG. The difference of this embodiment from the conventional type is that the commutation device 5
The commutation plate 26a also serving as an arc-extinguishing grid is extended to the arc-extinguishing chamber 16 side of the side plate 26 that supports the opening / closing mechanism 3, and the connection piece 15a of the load-side terminal 15 connected to the bimetal 31a fixed-side connection end is overlapped. Is fixed to the side plate 26. Therefore, in the configuration of the commutation device 5, only the commutation plate 26a is formed integrally with the side plate 26, and no other special members are required. The arc extinguishing chamber 16
The arc-extinguishing grids 16a are vertically arranged as one means adopted to further improve the breaking capacity in a limited space, and directly engage with the cost reduction of the commutation device 5. is not.

In the above configuration, a large current such as a short-circuit current flows in the electric circuit constituting section 2 of the circuit breaker for wiring, and the instantaneous trip of the overcurrent tripping device 4 causes the movable iron piece 32 and the latch 24 to be disengaged from each other. When the child 13 starts to separate, an arc 7 is generated between the fixed contact 12a and the movable contact 13a as shown in FIG. The movable contact 13 is a connecting portion 26b between the side plate 26 and the commutation plate 26a.
Approaching, the foot 7a of the arc 7 is commutated from the movable contact 13a to the connection portion 26b, drawn into the arc-extinguishing chamber 16 and extinguished. From this, the current that was initially flowing from the movable contact 13 to the load-side terminal 15 via the flexible conductor 14 and the bimetal 31 can be bypassed to the side plate 26,
The fixed contact, 12a, the movable contact 13a, the flexible conductor 14, and the bimetal 31 are protected from thermal stress. Therefore, the resistance to short-circuit current can be increased without increasing the heat capacity of the electric circuit component.

Next, two different embodiments of the commutation device for a circuit breaker according to the present invention will be described with reference to FIGS. 3 to 5 and FIGS. 6 to 8. FIG. The difference between these embodiments and the embodiment shown in FIG. 1 lies in the means for connecting the side plate 26 and the load-side terminal 15. First, the connecting means in the embodiment shown in FIGS.
A screw hole 15b is provided at a point where the fixed-side connection end and the connection piece 15 of the load-side terminal 15 overlap, and an adjusting screw 27 having a spherical end is screwed into the screw hole 15b. On the other hand, a guide hole 26c having a diameter smaller than the screw diameter is provided at a position where the tip of the adjustment screw 27 of the side plate 26 contacts, so that a stable contact state can be obtained and the tripping operation current of the bimetal 31 can be adjusted. It has become. Next, the connecting means in the embodiment shown in FIGS.
The contact piece 15c bent at a right angle is extended to the tip of the contact hole 15a, and the connection piece 15a is attached to the bimetal 31 in the same manner as in the embodiment of FIG.
Are fixedly connected to each other and a screw hole 15b is provided. An adjusting screw 28 that can freely advance and retreat and comes into contact with the surface of the side plate 26 is screwed into the screw hole 15b. On the other hand, a contact edge 26d is formed at a position of the side plate 26 opposite to the contact piece 15c so that the upper surface of the contact piece 15c is elastically slidably contacted. Therefore, in this embodiment, the tripping operation current of the bimetal 31 can be adjusted.

In the above configuration, both of the two embodiments differ from the above-described embodiment of FIG. 1 only in the means for connecting the side plate 26 and the load terminal 15, so that this connection is made securely. As far as possible, the process from arc generation at the time of interruption of short-circuit current to arc extinction via commutation is the same, and a description thereof will be omitted.

[Effect of the invention]

According to this invention, a commutation plate that also serves as a part of the arc-extinguishing grid is extended to a side plate made of a metal plate that supports an opening / closing mechanism, and a third plate is connected to a connection piece that is extended to a load-side terminal. By doing so, it is possible to provide an inexpensive commutation device of a circuit breaker for wiring that is easy to assemble without requiring special parts.

[Brief description of the drawings]

1 and 2 show an embodiment of a commutation device for a circuit breaker according to the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a diagram showing a commutation process of an arc during a breaking operation. FIGS. 3 to 5 and FIGS. 6 to 8 show two different embodiments of the commutation device of the circuit breaker according to the present invention, and FIG. 3 is a longitudinal sectional view of the former. FIG. 4 is an enlarged side view of an essential part of FIG. 3, FIG. 5 is an enlarged sectional view taken along line IV-IV of FIG.
FIG. 6 is a longitudinal sectional view of the main part of the latter, FIG. 7 is an enlarged side view of the main part of FIG. 6, FIG. 8 is a view on arrow P of FIG. 7, and FIG. It is a longitudinal section showing an example of a commutation device. 3 ... opening / closing mechanism, 5 ... commutation device, 12 ... fixed contact,
13 movable contact, 15 load terminal, 15a connection piece, 15b screw hole, 15c contact piece, 16 arc-extinguishing chamber, 16
a ... Arc extinguishing grid, 26 ... Side plate, 26a ... Commutation plate, 26d ... Contact edge, 27 ... Adjustment screw, 31 ... Bimetal.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Yamazaki 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi Inside Fuji Electric Co., Ltd. (56) References JP-A-56-42918 (JP, A) JP-A Sho 52-42268 (JP, A) JP-A-52-48067 (JP, A) Japanese Utility Model Application No. Sho 59-112456 (JP, U) Japanese Utility Model Application No. Sho 52-53365 (JP, U)

Claims (2)

(57) [Scope of request for utility model registration] An open / close mechanism for controlling the contact of a movable contact with a fixed contact is provided, and a side plate made of a metal plate is provided in an insulating case. A commutation plate formed by extending a part of the arc extinguishing grid to the position of the arc extinguishing grid is arranged on the side plate side of the arc extinguishing grid, connected to the load side terminal, and the tip is near the upper end of the side plate. Providing an extended connection piece, connecting the reverse flow plate side of the side plate to the tip of the connection piece, and connecting the fixed end of the overcurrent response element to the tip of the connection piece; A commutation device for a circuit breaker for wiring, wherein a movable end of the circuit breaker is connected to the movable contact. 2. A commutation device according to claim 1, wherein the connecting piece is connected by overlapping the tip of the connecting piece with one end of the overcurrent responsive element, and an adjusting screw is screwed into the connecting portion. A commutation device for a circuit breaker for wiring, wherein a tip of an adjusting screw is in contact with a side plate.