Pressure switch

Claim 1

A PRESSURE SWITCH, COMPRISING, A CYLINDER HAVING A PAIR OF ADJACENT, ALIGNED CHAMBERS THEREIN, ONE OF SAID CHAMBERS BEING SUBSTANTIALLY SMALLER IN BORE THAN THE OTHER, MEANS FOR SUPPLYING FLUID PRESSURE TO THE SMALLER OF SAID CHAMBERS, A DIFFERENTIAL PISTON DISPOSED WITHIN SAID CHAMBERS AND RESPONSIVE TO SAID FLUID PRESSURE TO BE MOVED THEREBY FROM THE SMALLER CHAMBER TOWARD THE LARGER CHAMBER TO A DEPRESSED POSITION, SAID PISTON INCLUDING A RELATIVELY LARGE PORTION DISPOSED WITHIN THE LARGER OF SAID CHAMBERS AND HAVING A RELATIVELY LARGE PISTON FACE THEREON, AND A RELATIVELY SMALL PORTION DISPOSED WITHIN THE SMALLER OF SAID CHAMBERS AND HAVING A RELATIVELY SMALL PISTON FACE THEREON EXPOSED TO SAID FLUID PRESSURE, EACH OF SAID PISTON PORTIONS HAVING A DIAMETER SLIGHTLY LESS THAN THE DIAMETER OF THE CHAMBER IN WHICH IT IS DISPOSED, AND BOTH OF SAID PISTON FACES BEING DIRECTED AWAY FROM SAID DEPRESSED POSITION, RESILIENT MEANS IN SAID CYLINDER FOR PRODUCING A FORCE ON SAID PISTON COUNTER TO THAT PRODUCED BY SAID FLUID PRESSURE AND FOR MAINTAINING SAID PISTON IN A NON-DEPRESSED POSITION IN THE ABSENCE OF SAID FLUID PRESSURE, TWO SPACED PAIRS OF CONTACTS MOUNTED ON SAID CYLINDER, A MOVABLE SWITCH ELEMENT ON SAID PISTON AND SUCCESSIVELY ENGAGEABLE WITH SAID PAIRS OF CONTACTS IN A SWITCH CLOSING POSITION WHEN SAID PISTON IS MOVED TOWARD A DEPRESSED POSITION, AND AN INSULATING MEANS ON SAID MOVABLE ELEMENT AND ENGAGEABLE WITH ONE PAIR OF SAID CONTACTS FOR PREVENTING CONCURRENT CLOSURE OF BOTH PAIR OF SAID CONTACTS WHEN SAID PISTON IS IN SAID DEPRESSED POSITION, SAID CYLINDER HAVING A BYPASS PORT EXTENDING FROM THE SMALLER CHAMBER TO THE LARGER CHAMBER FOR SUPPLYING FLUID PRESSURE TO SAID LATTER CHAMBER FOR ACTING ON SAID RELATIVELY LARGE PISTON FACE, THE INLET END OF SAID BYPASS PORT BEING POSITIONED SO THAT IT IS CLOSED BY THE SMALLER PORTION OF SAID PISTON WHEN THE PISTON IS IN SAID NON-DEPRESSED POSITION BUT IS AUTOMATICALLY OPENED WHEN SAID PISTON MOVES TO SAID DEPRESSED POSITION.