Abstract: The handle operator for a circuit breaker mounted in an enclosure is locked in the OFF position when the enclosure is opened by a lock-out member which directly engages the operator member of the handle operator which contacts and moves the circuit breaker handle. The lock-out member is a metal plate having an engagement edge which is positioned transverse to an engagement edge of the metal plate forming the handle operator member. Preferably, the lock-out member plate has a slot in which the engagement edge of the operator plate is received. The operator plate is pivotally mounted for rotation in its own plane and the lock-out plate slides parallel to the operator plate and has a flange providing the engagement edge which engages the operator plate at a point where any attempt to rotate the operator plate to move the circuit breaker handle toward the ON position, jams the lock-out plate into tighter contact with the operator plate.

Abstract: The handle of an electrical switch reciprocally movable in a slot in the switch housing is locked in a desired position by a locking mechanism which includes a base plate secured to the housing adjacent one end of the handle slot. A hasp member is hinged to the base plate at a hinge end for rotation about a hinge axis transverse to the path of reciprocal movement of the handle. The hasp member is rotatable between a locking position in which it overlaps the front end of the slot so that the handle cannot be moved away from the second end of the slot. A staple extending transversely from the base plate protrudes through an opening in the hasp member and has an opening for receiving one or more padlocks for locking the hasp member in the blocking position. In a second embodiment, the hasp member has a second opening through which the handle protrudes for locking the handle at the front end of the slot.

Abstract: An operating mechanism for an enclosure-mounted circuit breaker includes a slider for engaging the circuit breaker handle; a shaft-driven pivot for moving the slider between the handle on, off and reset positions; a holder for holding the slider in its reset position; a base plate for supporting the pivot and the slider; and a door-mounted rotary handle for rotating the shaft and operating the pivot. The rotary handle may engage the shaft in the on and off positions, and may be detached from the shaft in the reset position. The pivot may include a first pivot arm having a first cam surface for holding the slider in its reset position. A second cam surface on a second pivot arm may engage a first slider surface from off to on; a second slider surface from on to off, from off toward reset, and to resist reset to off; and an oblique slider surface when adjacent reset. The second cam surface may disengage the oblique surface at reset.