| 摘要 |
In a slow-make type circuit breaker for opening and closing a main circuit contact in synchronism with the manual operation of a rotary operation handle, a ratchet unit 12 as an artificial quick-make means for forcibly increasing the operating force of the operation handle in the middle of a stroke for ON operation of the contact is constituted by a convex cam 11 made of metal and coupled with the operation handle 5, a ratchet 12b made of metal and disposed at a point close to an ON position of the operation handle so as to face the cam, a driving spring 12c for pressing the ratchet toward a rotary movement path of the cam, and a ratchet case 12a in which these parts are incorporated. The unit is fabricated inside a cover 1b of a circuit breaker body. Here, the cam and the ratchet are formed as common parts, and the driving spring is selected in accordance with the kind of circuit breaker.
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