JPH0743912Y2 - Circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a circuit breaker called a circuit protector which is inserted into an electric circuit to interrupt a circuit through which an overcurrent flows to protect the circuit.

"Prior art" Conventional circuit breakers utilize heat generated by overcurrent, and there are some that break part of the circuit by deformation due to that heat to break the circuit, but a complicated forced trip mechanism is required However, the number of parts is large, assembly is troublesome, and the price is high.

Also, there is a simple structure such as a bimetal in which the thermal action plate itself performs the snap action, but this has a drawback that the frequency of contact welding accidents is high and the performance is not stable.

[Means for Solving the Problems] According to the present invention, the insulating substrate is provided with the first terminal, and one end of the heat plate is fixed to the first terminal. The heat-moving plate faces the substrate and extends substantially parallel to the substrate, and bends with respect to the substrate due to a temperature rise. Movable contact pieces are arranged substantially parallel to the heat plate and facing the substrate, and one end of the movable contact piece is overlapped with the free end portion of the heat plate to be connected and fixed. An arcuate spring is interposed between the other end of the movable contact piece and a locking portion projectingly fixed to the base plate, and the arcuate spring applies a biasing force to the movable contact piece in its extension direction. A second terminal facing the other end of the movable contact piece on the opposite side of the substrate is held by the substrate, a fixed contact is attached to the movable contact piece side of the second terminal, and the movable contact pressed against the movable contact is movable contact. Mounted on one side. The receiving portion is fixed to project on the substrate so as to face the connecting portion of the movable contact piece. The other end of the movable contact piece is bent at a substantially right angle so as to face the locking portion to form an engaging portion, and one end edge of the arc spring is formed in the engaging groove formed in the engaging portion and having a triangular cross section. Are inserted and engaged. The other end edge of the arcuate spring is inserted and locked in a locking groove having a triangular cross section formed in the locking portion. With no current flowing between the first terminal and the second terminal, and in the state where the fixed contact and the movable contact are in contact with each other, a straight line connecting the contact point and the engaging point of the engaging portion of the arcuate spring with respect to the straight line The engaging point with the engaging portion is slightly displaced on the side opposite to the substrate, and the connecting portion of the movable contact piece is in pressure contact with the receiving portion.

The first terminal and the second terminal are a thermal plate-movable contact piece-movable contact-
When electrically connected through a fixed contact and the current flowing between the first terminal and the second terminal exceeds a predetermined value, the substrate side of the heat plate expands due to the heating by Joule heat of the heat plate, which is opposite to the substrate. The side contracts and bends with respect to the substrate, so that the movable contact piece slightly rotates around the contact point of both contacts, and the engagement point of the arc spring and the movable contact piece is locked by the contact point of both contacts and the arc spring. When the movable contact is displaced toward the board side from the line connecting the locking point with the part, the movable contact snaps away from the fixed contact to the board side in a snap action, and the current between the first terminal and the second terminal is cut off. .

"Embodiment" FIG. 1 shows an embodiment of the present invention. A first terminal 12 is mounted on a substrate 11 of insulating material. In the figure, a base 13 is fixed to one corner of the substrate 11, and a plate-shaped first plate is provided on the upper end surface of the base 13.
The terminals 12 are brought into contact with each other and fixed with screws. Therefore the first terminal
The substrate 12 is substantially parallel to the substrate 11. One end of a heat plate 14 such as a bimetal is fixed to one end of the first terminal 12. The thermal plate 14 faces the substrate 11 and is substantially parallel to the substrate 11.

A movable contact piece 15 is arranged alongside the heat-moving plate 14 substantially parallel to the heat-moving plate 14, and one end of the movable contact piece 15 is overlapped with the free end of the heat-moving plate 14 to be fixedly connected. For this reason, one end of the movable contact piece 15 is bent at a substantially right angle in the plane toward the thermal plate 14 side, and the connecting portion 15a
And the connection portion 15a is connected to the heat plate 1. The movable contact piece 15 also faces the substrate 11 and is substantially parallel to this.

An arcuate spring is provided between the other end of the movable contact piece 15 and the fixed portion of the substrate 11.
16 are intervened. Therefore, in the figure, the locking part
17 is projectingly fixed on the substrate 11, the locking portion 17 faces the other end surface of the movable contact piece 15, and a locking groove 18 having a triangular cross section is formed in the facing surface, and the locking groove 18 is provided with an arcuate spring 16. One edge is inserted and locked. Further, the end portion of the movable contact piece 15 on the side of the engaging portion 17 is bent at a substantially right angle so as to face the engaging portion 15b to form an engaging portion 15b. An engaging groove 19 having a triangular cross-section is formed on the opposing surface of, and the other end edge of the arcuate spring 16 is inserted and engaged in the engaging groove 19.

The second contact is made near the end of the movable contact piece 15 on the side of the arcuate spring 16 and faces the second end.
The terminal 21 is held on the substrate 11. The base portion 22 is fixed on the substrate 11, and the plate-shaped second terminal 21 is brought into contact with the outgoing end surface of the base portion 22,
It is fixed with screws. The second terminal 21 is opposite to the substrate 11 and closely faces the movable contact piece 15. The movable contact piece of the second terminal 21
A fixed contact 23 is attached to the surface facing 15. Fixed contact 23
The movable contact 24 that is in contact with is attached to the movable contact piece 15.

When no current flows between the first terminal 12 and the second terminal 21 and the fixed contact 23 and the movable contact 24 are in contact with each other, this contact point P ₁
And a line 25 connecting the locking point P ₂ with the locking portion 17 of the arc spring 16
On the other hand, the engagement point P ₃ of the arcuate spring 16 with the movable contact piece 15 is the substrate 11
It is located slightly off on the opposite side. Due to this relationship, the movable contact 24 is pressed against the fixed contact 23 by the action of the arcuate spring 16, and the movable contact piece 15 receives a biasing force that compresses the longitudinal direction thereof.

Also, in this state, the connecting portion 15 of the movable contact piece 15 with the thermal plate 14 is
The connecting portion 15a of the movable contact piece 15 is in pressure contact with the receiving portion 26 that projects and is fixed on the substrate 11 so as to face the a. A protrusion that faces the intermediate portion of the movable contact piece 15 in the longitudinal direction and serves as a fulcrum at reset.
27 is projected on the substrate 11.

According to the above configuration, the first terminal 12 and the second terminal 21 are electrically connected to each other through the thermal plate 14, the movable contact piece 15, the movable contact 24, and the fixed contact 23. When an electric current is passed between the first terminal 12 and the second terminal 21, Joule heat is generated in the heat plate 14 to heat the heat plate 14, and the heat plate 14 extends on the substrate 11 side and the side opposite to the substrate 11. When the movable contact piece 15 contracts and bends in a direction along the substrate 11, the movable contact piece 15 slightly rotates in the clockwise direction in the figure around the contact point P ₁ of the contact point as shown in FIG. Junction P ₃ approaches line 25.

When an overcurrent larger than this state flows between the first terminal 12 and the second terminal 21, the thermal plate 14 is further curved, and therefore the engagement point P ₃ crosses the straight line 25 and approaches the substrate 11 side. At this moment, the movable contact 24 becomes the fixed contact 23 due to the action of the arc spring 16.
Further away, as shown in FIG. 4, it is abruptly displaced toward the substrate 11 side by snap action, and the first terminal 12 and the second terminal 21 are electrically disconnected.

To reset the disconnection state shown in FIG. 4 to the connection state shown in FIG. 2, as shown by an arrow 28 in FIG.
It suffices to push the free end of the above toward the receiving portion 26 side. At this time, the movable contact piece
The reference numeral 15 rotates counterclockwise in the figure with the projection 27 as a fulcrum, and returns to the state shown in FIG.

The receiving portion 26 is made of bimetal as shown in FIG. 5, and the substrate of the connecting portion between the movable contact piece 15 and the heat plate 14 according to the ambient temperature.
It is also possible to change the height relative to 11 so that the current break point is not affected by ambient temperature fluctuations.

Sixth example of combining the circuit breaker and the switch described above
Shown in the figure. In FIG. 6, parts corresponding to those in FIG. 1 are designated by the same reference numerals. An auxiliary plate 31 is provided at a right angle to the substrate 11 so as to be in contact with a side edge of the substrate 11, and the second terminal 21 is bent and extended on the auxiliary plate 31 at a right angle to form a rotation support portion 32. A rotary contact piece 33 is rotatably held on the rotary support portion 32, and
The third terminal 34 is fixed to the auxiliary plate 31 so as to face one end of 33. The knob 35 is rotatably held so as to face the rotary contact piece 33, and the slider 36 is projected on the inner surface of the knob 35.
Is biased by the coil spring 37 in the protruding direction.
When the knob 35 is moved in a seesaw manner, the protruding end of the slider 36 is reciprocally pivoted on the pivotal contact piece 33 to both sides of the pivotal support portion 32. Therefore, the pivotal contact piece 33 also moves in the seesaw motion, and the pivotal contact piece 33. And the third terminal
34 and 34 can be brought into and out of contact with each other, and a switch action is obtained. This switch action is provided on knob 35.
On the side to be turned on, the reset piece 38 is the connecting portion of the movable contact piece 15.
When the knob 35 is operated so as to push the reset piece 38, the taper surface 38a of the reset piece 38 is formed.
Then, the connecting portion 15a is pushed to the substrate 11 side, and the circuit breaker can be reset as described above.

"Effect of the Invention" As described above, the circuit breaker of the present invention has a heat pump 14, a movable contact piece 15, and an arcuate spring 16 as its main components, which is very simple. The second view, as will be appreciated from Figure 3, which rotates the engagement point P ₃ by a fulcrum contact points P ₁ by the force applied to the connecting portion 15a of the movable contact piece 15 by Netsudoban 14 Therefore, the connecting portion 15a, the contact point P ₁ , and the engagement point P _{3 are in a} lever relationship, and even if the contacts 23 and 24 are welded to each other to some extent, the thermal motion plate 14 is bent, The welding can be easily peeled off and the welding resistance is excellent. Heat plate
No. 14 does not apply unreasonable stress because it has a natural bending motion.

Further, the arcuate spring 16 has locking grooves 18 having triangular cross sections at both ends.
Since the movable contact piece 15 is stably locked in the engaging groove 19 and smoothly rotates around the locking point P ₂ as the movable contact piece 15 rotates, it does not hinder the rotation of the movable contact piece 15. Stable operating characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a circuit breaker according to the present invention, FIGS. 2 to 4 are front views showing respective operating states of the circuit breaker shown in FIG. 1, and FIG. FIG. 6 is a perspective view showing a part of a modification of the circuit breaker, and FIG. 6 is a perspective view showing an example in which the circuit breaker of the present invention and a switch are combined.

Claims (1)

[Scope of utility model registration request] 1. A substrate made of an insulating material, a first terminal mounted on the substrate, one end fixed to the first terminal, facing the substrate, extending substantially parallel to the substrate, A heat-moving plate that bends with respect to the substrate when it rises, and a heat-moving plate that is arranged substantially parallel to the heat-moving plate and facing the above-mentioned substrate, and one end of the heat-moving plate is overlapped and fixedly connected. A movable contact piece, and an arcuate spring interposed between the other end of the movable contact piece and a locking portion projectingly fixed to the substrate, and applying a biasing force in the extension direction of the movable contact piece, A second terminal held near the other end of the movable contact piece on the side opposite to the substrate and held by the substrate, a fixed contact attached to the movable contact piece side of the second terminal, and a fixed portion thereof. The movable contact, which is in contact with the contact and is attached to the movable contact piece, faces the connecting portion of the movable contact piece. And a receiving portion projectingly fixed on the substrate, the other end portion of the movable contact piece is bent at a substantially right angle so as to face the locking portion to form an engaging portion. One end edge of the arcuate spring is inserted and engaged in an engaging groove of triangular cross section formed in the joint portion, and the other end edge of the arcuate spring is inserted into an engaging groove of triangular cross section formed in the engaging portion. When the fixed contact and the movable contact are in contact with each other, no current flows between the first terminal and the second terminal, and the contact point and the locking portion of the arcuate spring are locked. The engagement point of the arcuate spring with the engagement portion is located slightly offset from the substrate with respect to the straight line connecting the point, and the connecting portion of the movable contact piece is in pressure contact with the receiving portion. Circuit breaker.