Rolling diaphragm devices having loose coupling between piston and piston rod to render the piston floating

Claim 1

A ROLLING DIAPHRAGM DEVICE PRECLUDING DAMAGE TO THE ROLLING DIAPHRAGM RESULTING FROM A MISALIGNMENT OF THE PISTON AND OF THE PISTON ROD OF THE DEVICE, SAID ROLLING DIAPHRAGM DEVICE INCLUDING (A) A CYLINDER BODY HAVING AN INTERNAL CYLINDRICAL WALL; (B) A RECIPROCATING PISTON ARRANGED INSIDE OF SAID CYLINDER BODY AND DEFINING A GAP BETWEEN THE LATERAL WALL THEREOF AND SAID CYLINDRICAL WALL OF SAID CYLINDER BODY; (C) A ROLLING DIAPHRAGM HAVING A RADIALLY OUTER FLANGE CLAMPED TO SAID CYLINDER BODY, A RADIALLY INNER FLANGE CLAMPED TO SAID PISTON, AND A ROLLING WALL INTERMEDIATE SAID RADIALLY OUTER FLANGE AND SAID RADIALLY INNER FLANGE FORMING A CONVOLUTION SITUATED INSIDE SAID GAP; (D) A PISTON ROD FOR OPERATING SAID PISTON, SAID PISTON ROD HAVING A CIRCULAR CROSS-SECTION OF PREDETERMINED DIAMETER; (E) A SLIDE-BEARING FOR SAID PISTON ROD INTEGRAL WITH SAID CYLINDER BODY; (F) A PLATE MEMBER ARRANGED INSIDE SAID PISTON AT RIGHT ANGLES TO THE AXIS THEREOF AND FORMING AN INTEGRAL PART THEREOF, SAID PLATE MEMBER HAVING A CIRCULAR APERTURE COAXIAL TO SAID PISTON AND HAVING A LARGER DIAMETER THAN SAID PISTON ROD, SAID PISTON ROD PROJECTING THROUGH SAID APERTURE LEAVING A SUBSTANTIAL RADIAL CLEARANCE BETWEEN SAID PISTON ROD AND SAID APERTURE IN SAID PLATE MEMBER ALLOWING THE END OF SAID PISTON ROD ADJACENT SAID PISTON TO MOVE RADIALLY RELATIVE TO SAID PISTON WITHIN THE LIMITS OF SAID APERTURE; AND (G) ABUTMENT MEANS ON SAID PISTON ROD COOPERATING WITH SAID PLATE MEMBER AND PROJECTING TRANSVERSELY ACROSS THE PORTION OF SAID PISTON ROD SITUATED BETWEEN THE END OF SAID PISTON ROD ADJACENT SAID PISTON AND SAID CIRCULAR APERTURE IN SAID PLATE MEMBER, WHEREBY SAID PLATE MEMBER ALLOWS MOVEMENT OF SAID ABUTMENT MEANS RELATIVE TO SAID PISTON IN A DIRECTION LONGITUDINALLY OF SAID PISTON ROD WITHIN LIMITS DEFINED BY SAID PISTON AND SAID CIRCULAR APERTURE IN SAID PLATE MEMBER.