Snap action switch

Claim 1

IN A SWITCH, A HOUSING, A CHAMBER IN SAID HOUSING, A PAIR OF SPACED TERMINALS EXTENDING THROUGH A WALL OF SAID HOUSING AND HAVING CONTACT PORTIONS SPACEDLY POSITIONED WITHIN SAID CHAMBER, A DIAPHRAGM DIVIDING SAID CHAMBER, A CONTACT MEMBER IN ENGAGEMENT WITH SAID DIAPHRAGM, YIELDING MEANS IN SAID CHAMBER AND POSITIONED TO HOLD SAID DIAPHRAGM AND CONTACT MEMBER AWAY FROM SAID TERMINAL PORTIONS, PASSAGE MEANS POSITIONED TO DELIVER FLUID PRESSURE AGAINST SAID DIAPHRAGM ON THE SIDE THEREOF OPPOSITE FROM THAT OPPOSED TO SAID TERMINAL PORTIONS, A CIRCULAR SEAT FORMED IN SAID CHAMBER AND POSITIONED TO RECEIVE A CENTRAL PORTION OF SAID DIAPHRAGM THEREAGAINST IN RESPONSE TO THE ACTION OF SAID YIELDING MEANS, SAID SEAT BEING SURROUNDED BY AN ANNULAR SEGMENT OF SAID CHAMBER, SAID MEANS FOR DELIVERING FLUID PRESSURE TO SAID DIAPHRAGM COMPRISING A PASSAGE COMMUNICATING WITH SAID ANNULAR CHAMBER SEGMENT, A WELL FORMED WITHIN SAID CIRCULAR SEAT, A PASSAGE FORMED IN SAID CIRCULAR SEAT AND POSITIONED TO PLACE SAID WELL IN COMMUNICATION WITH SAID ANNULAR CHAMBER SEGMENT AND CHECK VALVE MEANS POSITIONED TO PERMIT PASSAGE OF PRESSURE FROM SAID WELL TO SAID ANNULAR CHAMBER SEGMENT AND TO PREVENT PASSAGE OF FLUID PRESSURE FROM SAID ANNULAR CHAMBER SEGMENT TO SAID WELL.