Vacuum switch

Claim 1

A SWITCHING SYSTEM, COMPRISING A CLOSED CASING, MEANS CONNECTED TO SAID CASING FOR MAINTAINING A VACUUM THEREIN, SAID CASING HAVING AN OPENING IN ONE WALL THEREOF, A PERFORATED, HOLLOW CYLINDRICAL MEMBER IN SAID CASING AXIALLY ALIGNED WITH SAID OPENING, SAID MEMBER HAVING A RADIAL HOLE, A PISTON MOVABLY MOUNTED IN SAID MEMBER, SPRING MEANS IN SAID MEMBER BEARING ON SAID PISTON AND URGING SAID PISTON TO CLOSE SAID HOLE, A TUBE CONNECTED TO SAID OPENING, A VALVE CONNECTED TO SAID TUBE AND COMMUNICATING WITH THE ATMOSPHERE FOR ADMITTING AIR TO THE TUBE AND RETRACTION OF THE PISTON WHEN THE VALVE IS OPEN, A PAIR OF NORMALLY OPEN SWITCH CONTACTS DISPOSED IN SAID CASING, AN ELECTRIC APPARATUS IN CIRCUIT WITH SAID SWITCH CONTACTS ADAPTED TO BE OPERATED WHEN THE SWITCH CONTACTS ARE CLOSED, AN ACTUATING ELEMENT CARRIED BY SAID PISTON DISPOSED TO CLOSE THE SWITCH CONTACTS WHEN THE PISTON IS RETRACTED, SAID VALVE INCLUDING A HEAD HAVING A PASSAGE THERETHROUGH COMMUNICATING WITH SAID TUBE, A FLEXIBLE VALVE ELEMENT CARRIED BY SAID HEAD IN NORMALLY OPEN POSITION, AND A SHEET SUPPORTED BETWEEN SUPPLY AND TAKEUP ROLLERS AND MOVABLE PAST SAID HEAD AND DIRECTLY AGAINST SAID VALVE ELEMENT UNDER TENSION SO THAT SAID FLEXIBLE VALVE ELEMENT IS RETRACTED TO CLOSE SAID PASSAGE, SAID SHEET HAVING SPACED PERFORATIONS ARRANGED IN A COLUMN EXTENDING LENGTHWISE OF THE SHEET IN ALIGNMENT WITH SAID VALVE ELEMENT, WHEREBY SAID VALVE ELEMENT AUTOMATICALLY ENTERS SAID PERFORATIONS AND OPEN SAID PASSAGE FOR CLOSING SAID