Double acting actuator or pump having a pair of rolling diaphragms

Claim 1

IN A DOUBLE ACTING ACTUATOR OR PUMP THE COMBINATION OF: (A) A CYLINDER BODY DEFINING A CYLINDRICAL SPACE; (B) A RECIRPOCATING TANDEM PISTON INSIDE SAID CYLINDER BODY DEFINING A GAP BETWEEN THE RADIALLY OUTER LATERAL SURFACE THEREOF AND THE RADIALLY INNER SURFACE OF SAID CYLINDER BODY, SAID TANDEM PISTON DEFINING A TOTALLY ENCLOSED SPACE BOUNDED BY A PAIR OF END SURFACES AND BY A LATERAL; AND (C) A PAIR OF ROLLING DIAPHRAGMS SUBJECT TO COLLAPSE IN CASE OF PRESSURE REVERSAL, EACH OF SAID PAIR OF ROLLING DIAPHRAGMS HAVING A RADIALLY OUTER PORTION SECURED TO SAID CYLINDER BODY, A RADIALLY INNER PORTION SECURED TO ONE OF SAID PAIR OF END SURFACES OF SAID TANDEM PISTON AND A ROLLING WALL INTERMEDIATE SAID RADIALLY OUTER PORTION AND SAID RADIALLY INNER PORTION ARRANGED INSIDE SAID GAP BETWEEN SAID RADIALLY OUTER SURFACE OF SAID TANDEM PISTON AND SAID RADIALLY INNER SURFACE OF SAID CYLINDER BODY, SAID ROLLING WALL OF EACH OF SAID PAIR OF DIAPHRAGMS BEING SUFFICIENTLY LONG TO LEAVE BUT A RELATIVELY SMALL CLEARANCE BETWEEN THE JUXTAPOSED CONVOLUTIONS FORMED BY SAID ROLLING WALL OF EACH OF SAID PAIR OF DIAPHRAGMS, SAID PAIR OF DIAPHRAGMS SUBDIVIDING SAID CYLINDRICAL SPACE DEFINED BY SAID CYLINDER BODY INTO A PAIR OF AXIALLY OUTER CHAMBERS AND AN AXIALLY INNER CHAMBER NOT COMMUNICATING WITH SAID TOTALLY ENCLOSED SPACE DEFINED BY SAID TANDEM PISTON AND HAVING SUCH A SMALL VOLUME RELATIVE TO THE VOLUME OF EACH OF SAID PAIR OF AXIALLY OUTER CHAMBERS THAT ANY FORCE RESULTING FROM FORMATION OF A VACUUM IN ONE OF SAID PAIR OF AXIALLY OUTER CHAMBERS INCIDENT TO THE SUCTION ACTION OF SAID TANDEM PISTON AND ACTING UPON ONE OF SAID PAIR OF ROLLING DIAPHRAGMS IS BALANCED BY AN OPPOSITE FORCE RESULTING FROM THE FORMATION OF A VACUUM WITHIN SAID AXIALLY INNER CHAMBER.