| 摘要 |
A circuit breaker includes a movable contact, a fixed contact, a switching device, a switching operation handle, and an over-current tripping device. The switching device has a switching lever connected to the handle, a toggle linkage having an upper link and a lower link for connecting to the movable contact, a tripping mechanism for activating the toggle linkage in response to over-current, and an operation spring tightly stretched between the switching lever and the toggle linkage. A locking member is provided in the switching device for interconnecting the toggle linkage and the switching lever and for restricting a movement range of the switching lever according to an operational position of the toggle linkage. When main-circuit contact points are stuck, the locking member restricts the movement of the switching lever and prevents the handle from moving to the OFF position.
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