Track pin seal

Claim 1

AN ENDLESS TRACK LINK CONSTRUCTION COMPRISING: A BUSHING HAVING COAXIAL CYLINDRICAL INNER AND OUTER SURFACES AND AN AXIALLY OUTWARD FACING FLAT SEALING SURFACE ON ONE OF ITS AXIALLY OPPOSITE ENDS, A FIRST SIDE BAR HAVING A BUSHING BORE IN PRESS FIT RELATIONSHIP WITH SAID ONE END OF SAID BUSHING, A CYLINDRICAL PIN EXTENDING THROUGH SAID BUSHING WITH ONE END EXTENDING AXIALLY BEYOND SAID ONE END OF SAID BUSHING, A SECOND SIDE BAR HAVING A PIN BORE IN PRESS FIT RELATIONSHIP WITH SAID ONE END OF SAID PIN, A COUNTERBORE IN SAID SECOND SIDE BAR IN CONFRONTING RELATION TO SAID ONE END OF SAID BUSHING, AND AN ANNULAR SEAL STRUCTURE HAVING AN ANNULARLY CONTINUOUS AND RESILIENTLY FLEXIBLE NONMETALLIC BACKUP PORTION IN STATIC SEALING ENGAGEMENT WITH SAID COUNTERBORE AND INCLUDING ANNULAR SURFACES CONVERGING RADIALLY AND AXIALLY INWARDLY FROM ITS AXIALLY OPPOSITE SIDES TO AN ANNULAR WIPING EDGE IN NONROTATABLE SEALING ENGAGEMENT WITH SAID PIN, AND A HARD RELATIVELY INFLEXIBLE ANNULAR SEAL RING PORTION HAVING A FLAT AND ANNULARLY CONTINUOUS SEALING FACE AT ONE OF ITS AXIALLY OPPOSITE SIDES IN RELATIVELY ROTATABLE SEALING ENGAGEMENT WITH SAID SEALING SURFACE ON SAID BUSHING AND HAVING ITS OTHER AXIAL SIDE BONDED TO SAID FLEXIBLE PORTION, SAID SEAL RING PORTION HAVING AN INTERIOR DIAMETER SUBSTANTIALLY GREATER THAN THE DIAMETER OF SAID PIN AND AN EXTERIOR DIAMETER SUBSTANTIALLY SMALLER THAN THE EXTERIOR DIAMETER OF SAID FLEXIBLE PORTION.