O-ring rotary seal construction

Claim 1

IN A CARTRIDGE-TYPE SEAL FOR INSERTION IN THE ANNULAR SPACE BETWEEN A SHAFT AND A FRAME OPENING DEFINING FIRST AND SECOND CONCENTRIC CYLINDRICAL SURFACES, THE COMBINATION COMPRISING AN ANNULAR CARTRIDGE HAVING A FIRST WALL AND A SECOND WALL, SAID WALLS BEING FIXEDLY MOUNTED WITH RESPECT TO THE FIRST CYLINDRICAL SURFACE AND EXTENDING TO WITHIN THE VICINITY OF THE SECOND CYLINDRICAL SURFACE TO DEFINE AN ANNULAR CLEARANCE SPACE WITH RESPECT TO THE LATTER, AN O-RING PRESENTING ARCUATE SEALING SURFACES IN ENGAGEMENT WITH THE FIRST WALL OF THE CARTRIDGE AND THE SECOND CYLINDRICAL SURFACE RESPECTIVELY, A RETAINING RING OF PLASTIC OR THE LIKE ARRANGED ADJACENT THE O-RING FOR MOUNTING ON SAID SECOND CYLINDRICAL SURFACE, SAID O-RING AND RETAINING RING HAVING ADJACENT PORTIONS OF APPROXIMATELY THE SAME RADIAL THICKNESS PROFILED TO DEFINE A SHALLOW ANNULAR VALLEY BETWEEN THEM, A GARTER SPRING IN SAID VALLEY, SAID GARTER SPRING BEING PRESTRESSED TO EXERT BOTH THE RETAINING RING AND O-RING ANGLED FORCES HAVING RADIAL COMPONENTS IN THE SAME DIRECTION AS WELL AS AXIAL COMPONENTS IN OPPOSITE DIRECTIONS, SAID RETAINING RING BEING IN GRIPPING ENGAGEMENT WITH THE SECOND CYLINDRICAL SURFACE TO PRECLUDE RELATIVE MOVEMENT BETWEEN THE O-RING AND RETAINING RING.