Abstract: A fast-action solenoid actuating mechanism operable against high opposing loads and wherein the load being moved is connected to the solenoid armature by energy storing means effective to store increasing amounts of energy as the armature moves toward its retracted position. The energy storing means typically comprises a plurality of springs having very substantially differing spring rates and so arranged that initial movement of the armature is opposed primarily by the lower rate spring means and thereafter by the higher rate spring means until the accumulated stored energy together with the magnetic energy exceeds a required load operating force as the armature moves into its fully retracted position. All stored energy is automatically released during the final approach to retracted position and the armature is free to return to its extended position when the solenoid is de-energized. The mechanism may be utilized to operate a wide variety of devices such as switches, relays, valves, etc.