Vacuum operated pump

Claim 1

IN A TWO-STAGE PUMP, IN COMBINATION, A HOUSING HAVING FIRST AND SECOND PORTIONS JOINED TO FORM A CHAMBER, A FLEXIBLE DIAPHRAM EXTENDING TRANSVERSELY OF SAID CHAMBER AND HAVING THE OUTER PERIPHERY THEREOF IN SEALING ENGAGEMENT WITH THE JUNCTION OF SAID HOUSING PORTIONS FOR DIVIDING SAID CHAMBER INTO TWO COMPARTMENTS, SAID HOUSING INCLUDING TWO CYLINDER MEANS ONE AT EACH OF OPPOSITE SIDES OF THE DIAPHRAM, A PISTON IN EACH OF SAID CYLINDERS, EACH OF SAID PISTONS HAVING A PISTON ROD PORTION EXTENDING INTO ENGAGEMENT WITH ONE SIDE OF SAID DIAPHRAGM, ONE OF SAID PISTON ROD PORTIONS EXTENDING THROUGH SAID DIAPHRAGM INTO AN ATTACHMENT JUNCTURE WITH THE OTHER OF THE PISTON ROD PORTIONS, SAID DIAPHRAGM BEING RETAINED BETWEEN SAID PISTON ROD PORTIONS IN THE CENTRAL AREA OF THE DIAPHRAGM, ONE OF SAID PISTON ROD PORTIONS HAVING A VALVE CHAMBER THEREIN AT THE ATTACHMENT JUNCTURE THEREOF, GENERALLY ALIGNED PASSAGE MEANS EXTENDING THROUGH SAID PISTON ROD PORTIONS FROM EACH OF OPPOSITE SIDES OF SAID VALVE CHAMBER AND THROUGH EACH OF SAID PISTONS FOR FLUID CONNECTION OF SAID VALVE CHAMBER WITH BOTH OF SAID CYLINDERS, A SINGLE VALVE MEMBER IN SAID VALVE CHAMBER PROVIDING THE DUAL FUNCTION OF A DISCHARGE VALVE FOR ONE OF SAID CYLINDERS AND AN INLET VALVE FOR THE OTHER OF SAID CYLINDERS FOR CONTROL OF DISCHARGE OF PRESSURIZED FLUID FROM SAID ONE CYLINDER INTO SAID OTHER CYLINDER, AND CONTROL MEANS ACTUATED BY ONE OF SAID PISTONS FOR ALTERNATELY AND OPPOSITELY CONNECTING SAID COMPARTMENTS TO SOURCES OF HIGH AND LOW PRESSURE FOR CAUSING SAID DIAPHRAGM TO EFFECT RECIPROCATION OF SAID PISTONS.