Door-mounted operating mechanism for electrical switchgear

Abstract

The present invention is for use with high-tension electrical switchgear enclosed within a cabinet. The output shaft of a spring operating mechanism mounted on the exterior of the main safety door extends through the door and is connected to a bell crank. As the shaft rotates the bell crank, it imparts force to a first substantially vertical push rod which in turn imparts force to a second bell crank. An arm of the second bell crank imparts force to a second push rod which is connected to a lever arm that is connected to the operating shaft of the electrical switch, thereby opening or closing the switch. The first push rod has ball joints at both ends and a free twisting joint along the rod, thereby allowing opening of the door without disconnecting the operating mechanism. A push rod connected to the first bell crank engages a lip affixed to the cabinet wall to prevent opening of the door when the switch is closed. A switch detent, rotatably mounted to the interior of the door on an interlock shaft, is spring-biased to engage the first bell crank when the door is open, preventing closing of the switch. When the door is closed, a push rod engages the wall of the cabinet and rotates a lever arm affixed to the interlock shaft, rotating the detent away from the first bell crank, allowing closing of the switch.