Magnetically operated electric switch

Claim 1

AN ELECTRIC SWITCH, COMPRISING A PAIR OF FERROMAGNETIC CONTACTS MOVABLE WITH REFERENCE TO EACH OTHER BETWEEN CONDITIONS OF ENGAGEMENT AND DISENGAGEMENT AND NORMALLY ASSUMING ONE OF SAID CONDITIONS; A CYLINDER DEFINING A CHAMBER HAVING A FIRST END AND A SECOND END; ACTUATING MEANS INCLUDING A PISTON CONSTITUTING A FIRST AXIALLY MAGNETIZED PERMAMENT MAGNET AND MOVABLE IN SAID CHAMBER BETWEEN A FIRST POSITION IN WHICH THE FIELD OF SAID PERMANENT MAGNET IS EFFECTIVE TO CHANGE THE CONDITION OF SAID CONTACTS AND A SECOND POSITION IN WHICH SAID FIELD IS INEFFECTIVE UPON SAID CONTACTS; A SECOND AXIALLY MAGNETIZED PERMANENT MAGNET PROVIDED IN SAID CYLINDER AT ONE END OF SAID CHAMBER, SAID PERMANENT MAGNETS HAVING THEIR AXES IN ALIGNMENT AND HAVING LIKE POLES ADJACENT TO EACH OTHER SO THAT SAID PISTON IS NORMALLY BIASED TO ONE OF SAID POSITIONS AT THE OTHER END OF SAID CHAMBER; AND FLUID-CONVEYING CONDUIT MEANS COMMUNICATING WITH SAID CYLINDER AT THE OTHER END OF SAID CHAMBER AND AT THE RESPECTIVE SIDE OF SAID PISTON, SAID PISTON BEING RESPONSIVE TO A PREDETERMINED FLUID PRESSURE CHANGE IN SAID CONDUIT MEANS TO MOVE FORM SAID ONE TO THE OTHER POSITION THEREOF.