Sealing structure for piston and cylinder device

Claim 1

IN A PISTON AND CYLINDER DEVICE, AN ANNULAR SEAL FOR SEALING BETWEEN RELATIVELY RECIPROCATING PARTS, COMPRISING: A METALLIC MEMBER HAVING AN ANNULAR SURFACE FOR GUIDING SAID PARTS IN SAID RECIPROCATION, SAID MEMBERS HAVING AN ANNULAR PORTION EXTENDING LONGITUDINALLY IN THE DIRECTION OF RECIPROCATION AND HAVING A SHOULDER ADJACENT BUT SPACED FROM SAID ANNULAR SURFACE; A CLAMPING MEMBER OPPOSED TO SAID METALLIC MEMBER AND FORMING A FINITE CAVITY THEREWITH FOR RECEIVING A RESILIENT SEAL, SAID CLAMPING MEMBER FACIALLY ABUTTING SAID METALLIC MEMBER AND SAID RESILIENT SEAL ALONG A LINE GENERALLY PERPENDICULAR TO THE AXIS OF THE RECIPROCATING PARTS; AND AN ANNULAR RESILIENT ONE-PIECE SEAL HAVING A LIP PORTION EXTENDING LONGITUDINALLY IN THE DIRECTION OF SAID RECIPROCATION FOR SEALING BETWEEN THE RELATIVELY MOVABLE PARTS, AND A BASE PORTION EXTENDING GENERALFLY RADIALLY THEREFROM INTO SAID CAVITY, SAID BASE HAVING A HEEL AT THE JUNCTION OF SAID LIP PORTION AND BASE PORTION WITH A STEP AT THE HEEL SEATED ON SAID SHOULDER, SAID SHOULDER HOLDING BASE OF THE SEAL WITHIN SAID CAVITY AND THE HEEL OF THE SEAL AWAY FROM THE RELATIVELY RECIPROCATING SURFACE SEALINGLY ENGAGED BY THE SEALING LIP PORTION.