Square D Company

Walter C Karch

Joseph J Gribble

A manually operated snap acting switch having contacts in a circuit connecting an electric source to an electric load. The switch has contacts operated by a toggle mechanism and includes elements and mechanisms for causing the levers of the toggle mechanism to move to a tripped position and the contacts of the switch to open whenever the current in the circuit exceeds a predetermined value or in event of a power failure of the source. The elements and mechanism causing the movement of the levers to the tripped position and an opening of the circuit in event the source has a power failure include a spring-biased lever, a solenoid, which is continuously energized by the source, and a latch which is moved to released position by the solenoid plunger when the solenoid is de-energized. The lever which causes the toggle levers to move to the tripped position is held in an inactive position by the latch and moves to an active position when the solenoid is de-energized and the latch is moved to its released position. The solenoid, latch and spring-biased lever are positioned in a cavity in the base of the switch and the toggle mechanism is arranged so its levers do not move to the tripped position when the toggle levers are in the OFF position and the power of the source fails.

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Grafton, WI, United States of America

Walter C Karch