General Signal Corporation

Maria Toth

Frank L Browne

Frederick A Reker

A simplified linkage and cam member having first and second cam surfaces for interacting with a bail to drive said bail between first and second limits is provided. The cam surfaces restrict the movement of the bail when the bail is at either limit. However, when the bail is intermediate of the limits, the relationship of the effective portions of the cam surfaces allow increased bail movement for a given position of the cam member and associated cam surfaces. The structure is particularly well adapted for actuating a bail from a first to a second position wherein forces other than those applied by the cam also act on the bail; and at a critical bail position, the other forces take control and urge continued motion of the bail independent of the cam member. In such structure, the bail is first urged to move by the first cam surface, and at a critical point in its movement, it jumps from the first cam surface to the second cam surface and, for at least part of the remaining motion of the bail, the second cam surface serves to restrain the bail motion. The cam surfaces may be symmetrical in design and provide effective forces on the bail at both the start and end of the motion. The bail may, for example, constitute the actuating arm of a circuit breaker which is within an enclosure and actuated by an external arm coupled by the linkage and cam member.

Cam member for actuating and/or restraining the motion of a bail

When electrical equipment is used in a hazardous atmosphere, it must be enclosed in an explosion proof enclosure so an electrical spark cannot cause a fire or explosion. The present invention provides a means for assuring that an explosion proof enclosure which has been opened for inspection, repair or adjustment of the electrical apparatus is restored to its original condition. To this end, a visually inspectable locking means is provided. The locking means can be engaged only when the enclosure compartment and its associated cover are restored to their original explosion proof relationship. The locking means does not exert any distorting force on the mating threads of the enclosure.

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Terryville, CT, United States of America

Maria Toth