JP2009259438A - Overcurrent tripping mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overcurrent tripping mechanism with a small number of parts, in which bimetal action is supported by biasing a force that makes the bimetal bend by overcurrent to push an engagement member to an engaging release direction, and in which the time necessary to block a current path is made constant. <P>SOLUTION: The overcurrent tripping mechanism prepared in a case of a circuit breaker includes a bimetal formed of long plates with one end fixed, and an engagement member push-driven by bimetal, wherein the biasing means is provided near an arrangement position of the bimetal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an overcurrent tripping mechanism in a circuit breaker.

  Conventionally, in a circuit breaker using an overcurrent tripping mechanism, as described in Patent Document 1, when an abnormality such as an overcurrent, a short circuit, or a leakage occurs in a main circuit, a bimetal provided in the case 21 The tripping mechanism composed of the contact piece 23 and the engagement piece 24 is driven to release the pressing of the movable contact by the opening / closing mechanism, and the main circuit is shut off by separating the movable contact from the fixed contact by a spring. There was a circuit breaker.

Further, in the circuit breaker using the overcurrent tripping mechanism, as described in Patent Document 2, when the engagement with the latch member is released inside the case 31, the contact is generated by the force accumulated at the normal time. The engaging piece 34 for forcibly opening the portion and the one end side as a fixed end and the other end side as a free end, and when the overcurrent flows through the energizing circuit, the free end presses the engaging piece 34 in the unlocking direction. There is a circuit breaker that houses a bimetal 33 to be driven, an adjustment screw that changes the relative positional relationship between the bimetal 33 and the engaging piece 34, and a nut member through which a screw hole into which the adjustment screw is screwed. It was.
JP 2004-55173 A JP2008-34313

  However, in the invention described in Patent Document 1, the bimetal is bent when an overcurrent flows, and the engaging piece is pressed in the release direction, but the force by which the bimetal attempts to press the engaging piece is not transmitted well to the engaging piece. There is a drawback that the engaging piece may not operate normally. Thereby, there exists a fault that the time until a latching piece interrupts | blocks an electric circuit becomes non-constant. Further, in order to solve this, it is conceivable to weaken the force for holding the engaging piece, but there is a drawback that the time until the electric circuit is cut off may be too short.

  Further, in the invention described in Patent Document 2, the bimetal is bent when an overcurrent flows, and the engaging piece is pressed in the release direction, but the force by which the bimetal attempts to press the engaging piece is not transmitted well to the engaging piece. There is a drawback that the engaging piece may not operate normally. Thereby, there exists a fault that the time until a latching piece interrupts | blocks an electric circuit becomes non-constant. Further, in order to solve this, it is conceivable to weaken the force for holding the engaging piece, but there is a drawback that the time until the electric circuit is cut off may be too short.

  For this reason, the problem to be solved by the present invention is that the overcurrent flows, the bimetal is bent, and the force to try to press the engaging piece in the release direction is urged to help the operation of the bimetal, and the electric circuit is interrupted. To provide an overcurrent tripping mechanism with a constant number of parts required until a certain number of parts is obtained.

  The overcurrent tripping mechanism of the present invention made to solve the above-described problem is an overcurrent tripping mechanism provided inside a case of a circuit breaker, and the overcurrent tripping mechanism is formed from a long plate. In addition, a biasing means is provided in the vicinity of the position where the bimetal is disposed, and a bimetal having one end fixed and the other end freely provided, and a hook piece that is pressed and driven by the bimetal.

  According to the overcurrent tripping mechanism of the present invention, it is possible to assist the force with which the bimetal presses the engaging piece by providing the biasing means in the vicinity of the arrangement position of the bimetal. As a result, it is possible to obtain a constant time until the force by which the bimetal attempts to press the engaging piece is normally transmitted and the electric circuit is cut off.

  In the present invention, a structure that can obtain a constant time until interruption of the electric circuit can be obtained with a small number of parts.

Embodiments of the present invention will be described below.
An overcurrent tripping mechanism provided in the case 1 and 11 of the circuit breaker, the overcurrent tripping mechanism is formed of a long plate and has one end fixed to the load seats 2 and 12 and the other end freely 2 and the engaging piece 4 that is pressed and driven by the bimetals 3 and 13, and the first biasing springs 5 and 15 are placed on the upper surfaces of the bimetals 3 and 13 near the fixing position of the bimetals 3 and 13 and the case 1. , 11, and the second urging springs 6, 16 are provided near the contact surface between the bimetals 3, 13 and the load seats 2, 12 between the lower portions of the load seats 2, 12 and the cases 1, 11. It was. By providing the first urging springs 5, 15 and the second urging springs 6, 16, it is possible to promote that the bimetal 3, 13 is bent and presses the engaging piece 4 due to overcurrent. In addition, it is possible to reduce the fear that the force of the bimetal 3 or 13 is not transmitted well to the engagement piece 4 and the electric circuit is not normally cut off.
The biasing means is not limited to the spring shown in the present embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  As described above, the overcurrent tripping mechanism of the present invention provides a biasing means for promoting the bending of the bimetal in the vicinity of the arrangement position of the bimetal, so that the electric circuit is normally interrupted when an overcurrent flows. It is what I do.

It is sectional drawing of the overcurrent tripping mechanism in Example 1 of this invention. It is an expanded sectional view of the A section in Example 1 of the present invention. It is sectional drawing of the overcurrent trip mechanism of patent document 1 in a prior art. It is sectional drawing of the overcurrent trip mechanism of patent document 2 in a prior art.

Explanation of symbols

1, 11, 21, 31 Case 2, 12, 22, 32 Bimetal 3, 13 Load seat 4, 24, 34 Engagement piece 5, 15 First biasing spring 6, 16 Second biasing spring

Claims (1)

  An overcurrent tripping mechanism provided inside a case of a circuit breaker, wherein the overcurrent tripping mechanism is formed of a long plate and has one end fixed and the other end freely provided, and the bimetal An overcurrent tripping mechanism comprising an engaging piece that is pressed and driven by a biasing means provided in the vicinity of the bimetal arrangement position.

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