Circuit-interrupting devices having pressure-operated contacts

Claim 1

AN ENCLOSED CIRCUIT-INTERRUPTING UNIT INCLUDING A RELATIVELY STATIONARY CONTACT AND A COOPERABLE PRESSUREOPERATED MOVABLE CONTACT, A MASS OF CONFINED CONDUCTING MATERIAL HAVING THE CHARACTERISTIC OF DESORBING AN ARCEXTINGUISHING GAS UPON THE PASSAGE OF EXCESS ELECTRICAL CURRENT THROUGH THE SAID MASS, MEANS CONNECTING SAID MASS IN THE ELECTRICAL CIRCUIT PASSING THROUGH THE CIRCUIT-INTERRUPTING UNIT, WHEREBY PRESSURE WILL BE GENERATED DURING THE PASSAGE OF EXCESS CURRENT THROUGH THE UNIT AND EFFECT OPENING OF THE MOVABLE CONTACT, PISTON MEANS ASSOCIATED WITH SAID PRESSURE-OPERATED MOVABLE CONTACT, MEANS DEFINING A BALLAST CHAMBER (52) BEHIND THE PISTON MEANS, MEANS DEFINING A PRESSURE CHAMBER (50) ABOUT THE SEPARABLE CONTACTS AND IN COMMUNICATION WITH SAID MASS OF CONDUCTING MATERIAL, AND RELATIVELY SMALL GAS-CONNECTING MEANS (28) PNEUMATICALLY CONNECTING THE BALLAST CHAMBER WITH THE PRESSURE CHAMBER TO THEREBY PREVENT AMBIENT TEMPERATURE CHANGES FROM EFFECTING OPENING OF THE CONTACTS BY THE EQUALIZATION OF THE SLIGHT INCREASE OF GAS PRESSURE BUILT UP IN THE PRESSURE CHAMBER.