摘要 |
<p>A switch (10) for providing a safety function when its main contacts are fused or stuck together in the "ON" position, comprising a housing (16) containing a pair of main contacts (42, 54), one being designated an ON contact, and the other main contact being carried by a movable switch arm (50) in the housing (16). This switch arm (50) has a first end which carries the movable main contact (54) and a second end, and spring means (56) mechanically coupled to the movable switch arm (50) normally bias the movable main contact (54) toward open position away from engagement with the ON contact. Switch operating means including movable actuator means (78) overcome the biasing force of the spring means (56) for moving the movable main contact (54) to closed position into engagement with the ON main contact. There are auxiliary safety contact means (60) 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 (50) when the actuator means (78) is moved to OFF position, but the movable main contact (54) remains fused or stuck to the ON main contact.</p> |