| 摘要 |
PROBLEM TO BE SOLVED: To prevent coupling by engagement of a lower part housing and an intermediate housing from breaking off because of the increase of inner pressure in a current break. SOLUTION: In a circuit breaker in which the intermediate housing 1 and the lower part housing 2 of a rectangular box type are provided, a power supply side fixed contact 3 and a negative load side fixed contact 4 are fitted into the intermediate housing 1 so as to be opposing in a front and rear direction, and on the other hand, a movable contact 17 to bridge between the power supply side fixed contact 3 and the negative load side fixed contact 4 is housed in the lower part housing 2, the lower part housing 2 in which an exhaust pit 21 of an arc gas is opened in front and rear walls is coupled with the lower part of the intermediate housing 1 via engagement parts 29, 30, and the power supply side fixed contact 3 and the negative load side fixed contact 4 are pressed down by the front and the rear walls from the back and front direction, a thin-walled part 35 is installed at one part 2a of the front and the rear walls of the lower part housing to press down the fixed contacts 3, 4, and by bending the front and rear walls 2a toward outside by the internal pressure which increases in a current break, the arc gas is made to be released outside from the lower part housing 2. COPYRIGHT: (C)2004,JPO
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