| 摘要 |
<p>SAFETY SWITCH A switch for providing a safety function when its main contacts are fused or stuck together in the "ON" position, comprising a housing containing a pair of main contacts, one being designated an ON contact, and the other main contact being carried by a movable switch arm in the housing. This switch arm has a first end which carries the movable main contact and a second end, and spring means mechanically coupled to the movable switch arm normally bias the movable main contact toward open position away from engagement with the ON contact. Switch operating means including movable actuator means overcome the biasing force of the spring means for moving the movable main contact to closed position into engagement with the ON main contact. There are auxiliary safety contact means within the switch housing for completing a safety circuit and/or for deenergizing the main circuit in response to abnormal movement of the movable switch arm when the actuator means is moved to OFF position, but the movable main contact remains fused or stuck to the ON main contact. In further embodiments, safety contact means become triggered and moved from a first to a second position for providing a safety function, for example by closing a safety circuit or by opening the main circuit, when the actuator means are moved to OFF position but the main contacts remain fused or stuck together in their ON relationship.</p> |
