JPH04169022A - Breaker bimetal and circuit breaker - Google Patents

Abstract

PURPOSE:To secure a contact pressure of a contact by bending a bimetal element in double to form the bending portion as a supporting point, one end as the fitting portion of a moving contact and the other end as the operating point of applied pressure so that the total length can be shortened and moderate snap motion can be performed. CONSTITUTION:As temperature rises, a bimetal element 1a is expanded bigger than a bimetal element 1b so that a bimetal 1 is curved and transformed counterclokwise while being kept at a bending angle and an operating point 4 is moved gradually to the same direction because a moving contact 5 is protruded on a fixed contact 6. When the direction of applied pressure F is moved to the left of a supporting point 2, all of the bimetal 1 is rotationally moved counterclockwise to set the moving contact 5 apart from the fixed contact 6. At this time, breaking motion is performed in an extremely short time because not only applied pressure F but also repulsion as a result of the transformation of the bimetal 1 causing the moving contact 5 to be pushed against the fixed contact 6 occur. It is thus possible to easily obtain sufficiently moderate snap motion and shorten the total length because of bending form.

Description

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

The present invention relates to a bimetal for a breaker and a circuit breaker with a manual opening/closing mechanism configured using the bimetal.

[Conventional technology]

Generally, small circuit breakers do not have a switch function that can be turned on and off manually, but only have a reset mechanism to turn them on from an off state. However, there is also a demand for a small breaker with a switch function, and to meet this demand, circuit breakers with a manual opening/closing mechanism have also been proposed (for example,
(See Publication No. 108).

[Problem to be solved by the invention]

The problem with the above publication is that the vertical dimension is large due to the characteristics of its structure, and the snap action during opening and closing does not provide a sufficient sense of moderation, and the contact pressure of the contact decreases just before shutting off. There may also be problems such as not being able to fine-tune the break time. The present invention has focused on this point and has been made for the purpose of obtaining a bimetal that can solve the above-mentioned problems and a small circuit breaker using the bimetal.

[Means to solve the problem]

In order to achieve the above-mentioned object, in the bimetal for a breaker of the present invention, a bimetal formed by stacking two bimetal elements is folded in half, and the bent portion is used as a fulcrum that is rotatably supported by a support member. is used as the mounting part for the movable contact, and the other end is used as the point of application of pressure force for snap action. Further, the circuit breaker of the present invention has a movable contact attached to one end of the above-mentioned bimetal folded in half, and a support member rotatably supports the fulcrum of the folded portion, and an extension line connecting the fulcrum of the bimetal and the other end is provided. An operating lever rotatably supported is provided, and a spring inserted between the operating lever and the other end of the bimetal applies a pressing force for a snap action to the bimetal, and the supporting member and the movable contact are The terminals are configured to open and close between the terminals connected to the fixed contacts provided correspondingly to the terminals.

[Effect]

FIGS. 1(a) and 1(b) are explanatory diagrams of the basic structure and operation of the bimetal of the present invention. The bimetal element 1 is composed of a bimetal element 1a having a high expansion coefficient and a bimetal element 1b having a low expansion coefficient, as in the well-known structure, but is bent into an L-shape at the center as shown in the figure. The bent portion serves as a fulcrum 2 that is rotatably supported by a support member (not shown), one end serves as a movable contact mounting portion 3 to which a movable contact 5 is attached, and the other end serves as a point of action 4 for the pressing force F for snap action. . 6 is a fixed contact arranged corresponding to the movable contact 5. In such a configuration, when the temperature rises, the element 1a expands more than the element tb, and the bimetal 1 deforms into a curve as shown by the dashed-dotted line in the figure while maintaining the bending angle.
Since the movable contact 5 is in contact with the fixed contact 6, the point of action 4 gradually moves to the left. When the direction of the pressurizing force F moves beyond the fulcrum 2 to the left, the entire bimetal 1 rotates counterclockwise, and the movable contact 5 separates from the fixed contact 6 as shown by the two-dot chain line in the figure. . The breaking operation at this time is performed in an extremely short time because not only the pressurizing force F but also the repulsive force due to the deformation of the bimetal 1 and the pressing of the movable contact 5 against the fixed contact 6 are applied. That is, according to the bimetal of the present invention, a snap action with sufficient moderation can be easily obtained, and since it is bent, the overall length is shortened, and the movable contact 5 is pressed against the fixed contact 6 by the deformation of the bimetal 1. This ensures that the necessary contact pressure is maintained even on the verge of disconnection. Note that FIG. 1(a) and FIG. 1Cb) show the case where the bending is reversed, and the basic operation remains the same except that the arrangement of the contacts 5 and 6 is reversed. Further, although the figure shows a case where the sheet is bent at 90 degrees, the bending angle is not limited to 90 degrees and can be arbitrarily selected. In addition, even if it is a straight line that is not bent, if a fulcrum is provided between the point of action and the contact part, the characteristics of a snapping action with a sense of moderation and ensuring contact pressure of the contact point can be exhibited as is.

【Example】

Next, an embodiment of a circuit breaker constructed using the bimetal of the present invention will be described with reference to FIG. 2 and the subsequent drawings. 11 is a case, 12 and 13 are terminals fixed to the case 11, 14 is a support portion formed on the terminal I2, and the fixed contact 6 is attached to the terminal 13. As shown in FIG. 4, a V-shaped notch 15 is provided on the upper edge of the support portion 14, and the bimetal l has protrusions 16 protruding from both side edges of the bent portion. This is the fulcrum point 2. Reference numeral 17 denotes an operating lever rotatably supported by the case 11, and the operating lever 17 is composed of a holder 18 attached to the case 11 via a shaft 19 and a knob 20 screwed into the holder 18. The shaft l9 is located almost directly above the notch 15, and a coil spring 21 is provided inside the holder 18 and inserted between the knob 20 and the point of action 4 at the end of the bimetal l. Pressure force for snap action is applied to l. This embodiment has the above-mentioned configuration, and the on state shown in FIG. 2 and the off state shown in FIG. 3 can be switched arbitrarily like a normal switch by operating 1<-17. can. Also, when an overcurrent flows in the off state, bimetal 1 bends as shown by the broken line, and when the point of action at the tip of bimetal 1 reaches the dead point, it instantly switches to the state shown in Figure 3 and the circuit is automatically cut off. be done. This state remains stable even when the bimetal l cools down and returns to its original shape, but the circuit will return to normal if it is manually turned on as shown in FIG. Note that by rotating the knob 20 and moving the inside of the holder I8 up and down, the pressing force of the spring 21 can be changed and the break time can be adjusted.

【Effect of the invention】

As is clear from the above embodiments, the bimetal for a breaker of the present invention is made by folding a bimetal element in half, using the folded part as a fulcrum, one end as a mounting part for a movable contact, and the other end as a point of application of pressing force. It is easy to obtain a bimetal with a short overall length, a snap action with a sense of moderation, and a secure contact pressure at the contact point. In addition, the circuit breaker of the present invention is constructed using the above-mentioned bimetal, and has advantages such as having a switch function while being small, providing a sufficient sense of moderation when opening and closing, and ensuring contact pressure at the contact points. It is possible to obtain a breaker with

[Brief explanation of drawings]

Figures 1 (a) and (b) are explanatory diagrams of the basic structure and operation of the bimetal of the present invention, Figures 2 and 3 are cross-sectional views of one embodiment of the circuit breaker of the present invention, and Figure 4. is a perspective view of the main part thereof. l...bimetal, la, lb...bimetal element, 2...fulcrum, 3...movable contact attachment part, 4...
... Point of action, 5... Movable contact, 6... Fixed contact, 11
...Case, 12.13...Terminal, 14...Support part, I5...Notch, 16...Protrusion, I7...Operation lever, I8...Holder, 19...・Axis, 20...
・Knob, 2I Coil spring, F... Pressure force for snap action. Patent applicant: Tokai Rika Denki Seisakusho Co., Ltd. Agent
Patent attorney Maeda Ao and 1 other person @ 11(a)
No. 1111 (bl happy figure 4

Claims (1)

[Claims] A bimetal (1) formed by stacking one or two bimetal elements (1a) (1b) is folded in half and the folded portion is rotatably supported by a support member (14) as a fulcrum. (2)
and one end is the attachment part (3) of the movable contact (5),
A bimetal for a breaker, characterized in that the other end is used as a pressure application point (4) for snap action. 2. A bimetal (1) that is folded in half, has a movable contact (5) attached to one end, and is rotatably supported at the fulcrum (2) of the folded portion by a support member (14); An operating lever (17) rotatably supported on an extension line connecting the fulcrum (2) and the other end, and a bimetallic member inserted between the operating lever (17) and the other end of the bimetal (1). (1) Pressure force (F) for snap action
a spring (21) that biases the support member (14) and a fixed contact (6) provided corresponding to the movable contact (5).
A circuit breaker characterized by comprising terminals (12) and (13) respectively connected to.