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A gasketed pipe joint including a dual-functional, composite gasket, which in addition to forming a seal between a pipe bell and a spigot provides a molding surface for forming a bent retainer in the hub of the pipe or fitting. The dual-functional composite gasket comprises a first axially disposed

A gasketed pipe joint including a dual-functional, composite gasket, which in addition to forming a seal between a pipe bell and a spigot provides a molding surface for forming a bent retainer in the hub of the pipe or fitting. The dual-functional composite gasket comprises a first axially disposed portion formed of a non-elastomeric, substantially rigid, substantially non-resilient plastic material and has a first leading edge and a first trailing edge, and a second axially disposed portion, adjacent the first axially disposed portion, formed of an elastomeric material. Preferably, the gasket comprises a major portion of the non-elastomeric, substantially rigid, substantially non-resilient plastic and a minor portion of the elastomeric material.

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What is claimed is: 1. 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 diame

What is claimed is: 1. 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 90째 or less. 2. The gasketed bell of claim 1, wherein said bent retainer is formed by heating and bending the retainer radially inward until the inner surface of the bent retainer is in direct contact with the outer surface of said non-elastomeric plastic portion of said composite gasket, said non-elastomeric plastic portion being a mold for forming said bent retainer. 3. The gasketed bell of claim 1, wherein said forward axially disposed non-elastomeric major portion comprises from about 51 percent by volume to about 80 percent by volume of said composite gasket and said rearward axially disposed elastomeric portion comprises a minor portion of said composite gasket. 4. The gasketed bell of claim 3, wherein said first trailing edge forms an extension of said non-elastomeric portion into said rearward axially disposed elastomeric portion of said composite gasket. 5. The gasketed bell of claim 4, wherein said extension has a generally axially extending, semi-rectangular cross section surrounded by said elastomeric portion of said composite gasket. 6. The gasketed bell of claim 1, wherein said second trailing edge forms a radially extending elastomeric sealing lip and an adjacent rounded corner, said rounded corner seated in said integral, circular, sharp angular corner of said groove, said composite gasket having no additional plastic retaining ring. 7. The gasketed bell of claim 1, wherein said forward axially disposed portion and said rearward axially disposed portion are fused together at said first trailing edge and second leading edge, and said circular, generally angular corner is axially spaced from said bent retainer by a generally cylindrical base of said internal groove. 8. The gasketed bell of claim 1, wherein said integral, circular, angular corner of said groove has an angle less than 90째. 9. The gasketed bell of claim 1, wherein said non-elastomeric, substantially non-flexible plastic is tinted by a color tint to match the color of said gasketed bell. 10. The gasketed bell of claim 9, wherein said color is red, green, yellow, blue or brown, or a hue of such color. 11. The gasketed bell of claim 1, wherein said forward axially disposed portion is substantially flexible in a radial direction. 12. The gasketed bell of claim 1, wherein said forward axially disposed portion is substantially non-flexible in a radial direction. 13. The gasketed bell of claim 1, wherein said non-elastomeric plastic is a polyolefin. 14. The gasketed bell of claim 13, wherein said elastomeric material is a natural or synthetic rubber. 15. The gasketed bell of claim 1, wherein said composite gasket consists of said forward axially disposed portion and said rearward axially disposed portion. 16. The gasketed bell of claim 1, wherein said forward, axially disposed portion is formed of a non-elastomeric, substantially rigid plastic selected from the group consisting of polyethylene, polypropylene, copolymers of polyethylene and polypropylene, and poly(vinyl chloride). 17. A method for seating a composite gasket in the cylindrical body of a pipe or fitting, the pipe or fitting having a longitudinal axis, which method is conducted in the following sequence, order: a) providing 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, preformed internal groove of a second diameter, said second diameter being greater than said first diameter, said internal groove being defined rearwardly by an integral, circular, angular corner, said integral, circular, angular corner of said internal groove having an angle of 90째 or less, b) inserting a generally cylindrical, dual-functional composite gasket into said groove, said 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 non-elastomeric 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 rearward axially disposed portion being formed of an elastomeric material, 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, said gasket being inserted into said groove such that said rounded corner is seated in said integral, circular, angular corner of said groove and said forwardly axially disposed portion of said gasket is facing axially toward the open end of said hub, and c) heating the outer edge of an end portion of said second diameter section of said hub and bending said heated end portion so as to cause said heated end portion to bend radially inward until the inner surface of said heated end is in substantial contact with said first leading edge of said non-elastomeric, substantially non-flexible plastic portion of said composite gasket which portion serves as a mold for said heated end portion, so as to provide said hub with a bent retainer in which there is substantially no gap between said inner surface of said heated end portion and said first leading edge of said non-elastomeric, substantially non-flexible plastic portion of said composite gasket. 18. The method of claim 17, wherein said non-elastomeric portion comprises a major portion by volume of said composite gasket and said elastomeric portion comprises a minor portion by volume of said composite gasket. 19. The method of claim 18, wherein said first trailing edge forms an extension of said non-elastomeric portion into said rearward axially disposed elastomeric portion of said composite gasket. 20. The method of claim 19, wherein said extension has a generally axially extending, semi-rectangular cross section surrounded by said elastomeric portion of said composite gasket. 21. The method of claim 18, wherein said forward axially disposed non-elastomeric portion is from about 51 percent by volume to about 80 percent by volume of said composite gasket and said rearward axially disposed elastomeric portion comprises the remainder of said composite gasket. 22. The method of claim 21, wherein said forward axially disposed non-elastomeric portion comprises from about 52 percent by volume to about 70 percent by volume of said composite gasket. 23. The method of claim 17, wherein said second trailing edge forms a radially extending elastomeric sealing lip and an adjacent rounded corner, said rounded corner seated in said integral, circular, sharp angular corner of said groove. 24. The method of claim 17, wherein said forward axially disposed portion and said rearward axially disposed portion are fused together at said first trailing edge and second leading edge. 25. The method of claim 17, wherein said integral, circular, angular corner of said groove has an angle of 90째 or less, said composite gasket having no additional plastic retaining ring. 26. The method of claim 17, wherein said forward axially disposed portion is substantially flexible in a radial direction. 27. The method of claim 17, wherein said forward axially disposed portion is substantially non-flexible in a radial direction. 28. The method of claim 17, wherein said non-elastomeric plastic is a polyolefin. 29. The method of claim 28, wherein said elastomeric material is a natural or synthetic rubber. 30. The method of claim 17, wherein said composite gasket consists of said forward axially disposed portion and said rearward axially disposed portion. 31. The method of claim 17, wherein said forward, axially disposed portion is formed of a non-elastomeric, substantially rigid plastic selected from the group consisting of polyethylene, polypropylene, copolymers of polyethylene and polypropylene, and poly(vinyl chloride). 32. A dual-functional, generally cylindrical, composite gasket for forming a seal between a pipe or fitting bell and a spigot comprising: a first axially disposed portion formed of a non-elastomeric, substantially rigid plastic and having a first leading edge and a first trailing edge, said non-elastomeric substantially rigid plastic being incapable of rapidly returning to its original length after being significantly stretched, said first 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, a second axially disposed portion formed of an elastomeric material, having a second leading edge and a second trailing edge, said first trailing edge of said first portion being in substantial contact and fixedly attached to the second leading edge of said second portion, said first and second axially disposed portions having substantially the same outer diameter at and proximal to the point of contact between said first trailing edge and said second leading edge to form a continuous outer surface therebetween, said first axially disposed portion being substantially non-flexible in the axial direction and comprising a major portion by volume of said dual-functional composite gasket and said second axially disposed portion comprising a minor portion by volume of said dual-functional composite gasket, said second trailing edge forming a radially extending elastomeric sealing lip and an adjacent rounded corner, said gasket being adapted for insertion into a groove of said bell such that said first axially disposed portion of said gasket receives said spigot prior to said second axially disposed portion of said gasket when said spigot is inserted into said bell. 33. The dual-functional composite gasket of claim 32, wherein said first trailing edge forms an extension of said first axially disposed portion into said rearward axially disposed portion of said composite gasket. 34. The dual-functional composite gasket of claim 33, wherein said extension has a generally axially extending, semi-rectangular cross section surrounded by said second axially disposed portion of said composite gasket. 35. The dual-functional composite gasket of claim 33, wherein said extension has a generally axially extending semi-dumbbell-shaped cross-section surrounded by said second axially disposed portion of said composite gasket. 36. The dual-functional composite gasket of claim 32, wherein said non-elastomeric plastic first axially disposed major portion comprises between about 52 and about 70 percent by volume of said composite gasket, said composite gasket having no additional plastic retaining ring. 37. The dual-functional composite gasket of claim 36, wherein said first axially disposed portion comprises about 60 percent by volume of said gasket. 38. The dual-functional composite gasket of claim 32, wherein said non-elastomeric plastic is tinted with a colored tint. 39. The dual-functional composite gasket of claim 38, wherein said colored tint renders the non-elastomeric portion red, green, yellow, blue or brown, or a hue of such color. 40. The dual-functional composite gasket of claim 32, wherein said elastomeric material is tinted with a colored tint. 41. The dual functional gasket of claim 32, wherein said first axially disposed portion is substantially flexible in a radial direction. 42. The dual functional gasket of claim 32, wherein said first axially disposed portion is substantially non-flexible in a radial direction. 43. The gasket of claim 32, wherein said non-elastomeric plastic is a polyolefin. 44. The gasketed bell of claim 43, wherein said elastomeric material is a natural or synthetic rubber. 45. The gasket of claim 32, wherein said composite gasket consists of said forward axially disposed portion and said rearward axially disposed portion. 46. The gasket of claim 32, wherein said forward, axially disposed portion is formed of a non-elastomeric, substantially rigid plastic selected from the group consisting of polyethylene, polypropylene, copolymers of polyethylene and polypropylene, and poly(vinyl chloride). 47. A pipe joint formed by inserting the insert end of a first plastic pipe into the gasketed plastic bell in the cylindrical body of a 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 said insert end of said plastic 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 an 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 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 rearward axially disposed portion being formed of an elastomeric material and being adjacent and in contact and fixedly attached to said forward axially disposed portion, said non-elastomeric portion comprises a major portion of said gasket in the range of up to about 80 percent by volume of said composite 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 having a cross-section of 90째 or less, said circular, generally angular corner axially spaced from said bent retainer by a cylindrical base of said internal groove, said bent retainer and said hub being of unitary construction, the outer surface of said first plastic pipe being spaced apart from the inner surface of said forward axially disposed portion and being in contact with the outer surface of said second trailing edge when said plastic pipe has been inserted into said gasketed plastic bell. 48. The pipe joint of claim 47, wherein said non-elastomeric plastic is a polyolefin. 49. The gasketed bell of claim 48, wherein said elastomeric material is a natural or synthetic rubber. 50. The pipe joint of claim 47, wherein said composite gasket consists of said forward axially disposed portion and said rearward axially disposed portion. 51. 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 inwardly extending 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 consists of 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 extending retainer, 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 rearward axially disposed portion being formed of an elastomeric material, and being adjacent and in contact with said forward axially disposed portion, said forward axially disposed portion being fixedly attached to said rearward axially disposed portion by fusion or adhesion to form a unitary gasket, said non-elastomeric plastic being incapable of rapidly returning to its original length after being significantly stretched, 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 having a cross-section of 90째 or less, said circular, generally angular corner axially spaced from said bent retainer by a cylindrical base of said internal groove. 52. The gasketed bell of claim 51, wherein said non-elastomeric portion comprises a major portion of said composite gasket and said elastomeric portion comprises a minor portion of said composite gasket. 53. The gasketed bell of claim 52, wherein said first trailing edge forms a generally axial extension of said first axially disposed portion into said rearward axially disposed portion of said gasket. 54. The gasketed bell of claim 51, wherein said forward axially disposed portion is substantially flexible in a radial direction.