Patent ID: 7880105
Filing Date: 2011-02-01
Classification: H01H

Abstract:
1. A circuit breaker comprising: a power transmission mechanism for driving a movable contact and a fixed contact constructing a make and break contact in a direction that said contacts separate from each other and contact thereon, an interruption spring imparting driving force in a direction that the driving force separates said movable contact from said fixed contact through said power transmission mechanism, a case incorporated with a latch mechanism for restricting movement of said power transmission mechanism at a place that an energized condition of said interruption spring is held, and a small case incorporated with a pull-out operation section for releasing the restriction of said power transmission mechanism by said latch mechanism and detachably fixed to said case, characterized in that said pull-out operation section incorporated in said small case is provided with a lever having first and second arms and rotatably supported on a shaft, and operation means for rotating said first arm, said operation means being arranged so as to oppose to said first arm of said lever, said lever is arranged so that a tip of said second arm is able to engage with and rest on said latch mechanism, and made so that the restriction of said power transmission mechanism by said latch mechanism is released by rotation of said lever, said small case is provided with at least for high speed interruption and for low speed interruption, and one of them combined with said case according to the duty, a gap between said first arm and said operation means is set larger for low speed interruption than for high speed interruption, and a ratio b