Patent ID: 7140618

Claim:
A gasketed bell in the cylindrical body of a pipe or fitting, the pipe or fitting having a longitudinal axis and comprising an enlarged, generally cylindrical, one piece plastic hub formed in the forward end of said body, said hub having a cylindrical section of a first diameter suitable to overfit an end of an adjacent length of pipe, said hub including an integral, radially inward open, internal groove of a second diameter, said second diameter being greater than said first diameter, said internal groove being defined forwardly by an integral, radially inward bent retainer at the open end of said hub where the end of said adjacent length of pipe is to be inserted, said internal groove being defined rearwardly by an integral, circular, generally angular corner, said internal groove having a generally cylindrical, dual-functional, composite gasket disposed therein, said composite gasket comprising forward and rearward axially disposed portions, said forward, axially disposed portion being formed of a non-elastomeric, substantially rigid plastic and being substantially non-flexible in the axial direction, and having a first leading edge and a first trailing edge, said first leading edge of said forward axially disposed portion being in substantial contact with the inner surface of said radially inwardly bent retainer, said non-elastomeric, substantially rigid plastic being incapable of rapidly returning to its original length after being significantly stretched, said forward axially disposed portion having a substantially cylindrical radially outward surface radially spaced from the longitudinal axis of the gasket by a substantially constant distance from substantially said first leading edge to substantially said first trailing edge, said forward axially disposed portion comprising the major portion by volume of said gasket, said rearward axially disposed portion being formed of an elastomeric material and being adjacent and in contact with and fixedly attached to said forward axially disposed portion, said rearward axially disposed portion comprising a minor portion by volume of said gasket, said rearward axially disposed portion having a second leading edge and a second trailing edge, said second leading edge of said second axially disposed portion being in contact with said first trailing edge of said forward axially disposed portion, said second trailing edge having a rounded corner seated in said integral, circular, angular corner of said internal groove, said circular generally angular corner having a cross-section of 90° or less.