JPH031875Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a circuit breaker using bimetal.

Conventionally, circuit breakers used in automobiles to protect high-current load circuits such as power windows, defoggers, and blower motors have a pair of terminal plates fixed to the bottom wall of the case, and a compression coil for operation inside the case. A holder that is always urged upward by a spring is arranged, a bimetal is attached to this holder via a pair of compression coil springs for contact pressure, and an adjustment screw is screwed into the case, and the tip of the holder is locking the bimetal and holding the bimetal in contact with the pair of terminal plates by a pair of compression coil springs for contact pressure;
When the bimetal is bent and deformed during an overcurrent, it becomes unlatched from the adjustment screw, and the bimetal along with the holder moves upward by the spring force of the operating compression coil spring and comes off from the pair of terminal plates. A configuration that performs a disconnection operation is common, but such a configuration has the disadvantage of requiring a large number of parts and increasing costs.

Therefore, an object of the present invention is to provide a circuit breaker that can reduce the number of parts and reduce costs.

To summarize the present invention, a spring member is interposed in an inclined manner between a bimetal and a case that are in contact with a pair of terminal plates, and this spring member increases the contact pressure against the pair of bimetal terminal plates and the pair of terminal plates. It is characterized by a structure in which a force for releasing the contact is obtained.

An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a plastic case with an open top, and a protrusion 1a is formed on the inner surface of the bottom wall of the case 1, oriented diagonally upward toward the front. 2, 2 are a pair of terminal boards, which are fixed to both the left and right ends of the bottom wall of the case 1 by caulking tongue pieces, etc.
Contact pieces 2a, 2a are formed at the upper end portions of the case 1, respectively, to extend along the inner surfaces of both the left and right end portions of the front wall of the case 1. 3
is a long bimetal on the left and right, and approximately in the center of its lower edge is a protrusion 3 pointing diagonally downward on the rear side.
A is formed, and contact portions 4, 4 are attached to both left and right end portions of the front portion by spot welding or the like. The bimetal 3 is disposed inside the case 1, and between the bimetal 3 and the bottom wall of the case 1 there are protrusions 3a, 1a on the top,
A compression coil spring 5, which is a spring member, is interposed with the lower end thereof being fitted. Therefore, the compression coil spring 5 is formed into an inclined shape that is oriented diagonally upward on the front side, and its contact portions 4, 4 are connected to the bimetal 3 by contact pieces 2a, 2a of the terminal plates 2, 2.
In addition, the upper edge of the bimetal 3 is connected to a locking member screwed into approximately the center of the front wall of the case 1. The bimetal 3 is locked to the tip of the barrel adjustment screw 6, and the bimetal 3 is prevented from moving upward, so that the contact portions 4, 4 are connected to the contact pieces 2 of the terminal plates 2, 2.
It is held at the original position in contact with a and 2a. 7
A lid member is attached to the upper opening of the case 1, and a return hole 7a is formed in this lid member.

Next, the operation of this embodiment will be explained. Terminal plates 2, 2 are interposed in large current load circuits such as automobile power windows, defoggers, blower motors, etc. One terminal plate 2, a contact piece 2a, a contact part 4,
A load current flows through the path of the bimetal 3, the contact portion 4, the contact piece 2a, and the other terminal plate 2. When an overcurrent flows, the bimetal 3 generates heat and bends and deforms inward of the case 1, and finally the upper edge of the bimetal 3 comes off the tip of the adjustment screw 6 and is unlocked. The bimetal 3 is moved by the upward force of the compression coil spring 5, and the contact portions 4, 4 are separated upward from the contact pieces 2a, 2a of the terminal plates 2, 2, and the contact is released. The circuit is opened and a breaker operation is performed. In this case, the upper edge of the bimetal 3 comes into contact with the back surface of the lid member 7, and the bimetal 3 comes to be stopped at the operating position. The bimetal 3 is located directly below the return hole 7a, and the lower edge of the bimetal 3 is located below the tip of the adjustment screw 6. Therefore, after the bimetal 3 is naturally cooled, if a push rod (not shown) is inserted into the return hole 7a of the lid member 7 and the upper edge of the bimetal 3 is pressed, the bimetal 3 will be pressed against the spring of the compression coil spring 5. The bimetal 3 is moved downward against the force, and the upper edge of the bimetal 3 is relatched to the tip of the adjustment screw 6, returning to its original position.

In the above embodiment, one compression coil spring 5 is interposed between the substantially central part of the bimetal 3 and the bottom wall of the case 1, but instead, the compression coil spring 5 is interposed between the left and right ends of the bimetal 3 and the case 1. Two compression coil springs may be interposed between the first and second bottom walls.

In addition, the present invention is not limited only to the embodiments described above and shown in the drawings, but can be applied not only as a circuit breaker for automobiles but also as a circuit breaker for general equipment without departing from the scope of the invention. Of course, it can be implemented with appropriate modifications.

As is clear from the embodiments described above, the present invention has a spring member interposed between the bimetal and the case in an inclined manner to prevent the component force in the direction in which the bimetal comes into contact with a pair of terminal plates and the contact. Since the structure is configured to obtain a component force in the releasing direction, there is no need for a conventional holder for mounting the bimetal and a pair of contact pressure compression coil springs for applying contact pressure to the bimetal, which reduces the number of parts. It is possible to provide a circuit breaker that has practical effects such as being able to reduce the number of parts, thereby reducing costs and reducing weight.

[Brief explanation of the drawing]

FIG. 1 is a vertical side view showing an embodiment of the present invention;
FIG. 2 is an exploded perspective view of the same embodiment. In the drawings, 1 is a case, 1a is a protrusion, 2 and 2 are terminal plates, 3 is a bimetal, 3a is a protrusion, 5 is a compression coil spring (spring member), and 6 is an adjustment screw (locking member).

Claims (1)

[Scope of utility model registration request] A pair of terminal boards fixed to a case, a bimetal disposed in the case so as to be in contact with these terminal boards, and a bimetal interposed in an inclined manner between the bimetal and the case, and the bimetal a spring member that applies a component of force in the direction of contacting the pair of terminal plates and a component of force in the direction of releasing the contact; and a spring member provided in the case that applies a component of force in the direction of releasing the contact of the spring member. A circuit breaker comprising: a locking member that locks the bimetal, and the bimetal is deformed by bending when an overcurrent occurs to release the circuit breaker from the locking member.