Condition-responsive spring driven actuator

In combination with an electrical circuit, a condition-responsive, spring driven actuator for an electrical switch comprising:

• an actuator housing, an axially displaceable actuator shaft concentrically related to said housing and connected to a contact for an electrical switch movable between a circuit-closed position and a circuit-open position, a helical compression spring seated within the housing and connected with said shaft for continuously urging said shaft to advance in axial displacement for moving said contact to a circuit-open position, means for restraining said shaft against axial displacement including a fulcrum mounted on said housing, a lever arm supported for pivotal motion by said fulcrum having one end attached to said shaft, the other end thereof being depressible relative to said one end for causing said shaft to be displaced against the applied force of said spring, means for supporting said other end in a depressed configuration comprising a frangible bar transversely related to said arm in spaced relation with said fulcrum for securing the arm against pivotal motion, means for supporting the bar at each of the opposite ends thereof in fixed relation with said housing, and means for causing said bar to separate for releasing said lever arm for pivotal motion, including a pendulous mass having a bore extended therethrough and suspended in concentric relation with said bar.