Circuit breaker having shock-proof trip-actuating assembly

The trip mechanism of a molded case type circuit breaker is actuated by a plunger that is integral with and axially extends from the end of a reciprocally-movable core member of a solenoid mounted within the breaker housing. The free end of the plunger strikes the trip bar of the breaker when the solenoid is energized in response to a current overload condition in the circuit being protected. The solenoid core member and plunger are mechanically locked in NO-TRIP position by spring-biased keeper means that is automatically released from its "lock" position by the magnetic field generated by the solenoid coil when it is energized. A spring automatically resets the trip-actuating assembly when the current-overload condition has been corrected and the solenoid coil is deenergized. The trip-actuating assembly is not only compact, reliable and inexpensive but is inherently adapted to withstand severe mechanical shocks and impacts, such as those encountered aboard naval vessels, and is thus especially suited for use in circuit breakers that will be employed to protect electrical circuits and equipment subjected to such rough service conditions.