Abstract: Certain pipe sections require an annular sealing gasket to be permanently positioned on the spigot portion. This is especially desirable with pipe sections formed with helically preceding reinforcing ribs. Disclosed is pipe section including a spigot end 2 having an annular groove 4 positioned adjacent the end surface thereof. Within groove 4 is placed fluid, settable bedding material 14 which has positioned therein and impregnated thereby a reinforcing material 15, preferably consisting of a ribbon of fiberglass material. Annular sealing gasket 3 is positioned in this groove 4 and onto the settable material 14 which is caused to intimately contact both the surface of the groove 4 and the sealing gasket 3. The thus sealed, bonded and reinforced spigot end retains the structural integrity and resistance to crushing loads and impact strength as is inherent in the rib reinforced pipe section.

Abstract: A coupling comprises a body of fiber glass reinforced plastic which has a rubber sleeve embedded therein. The rubber sleeve is a one piece unit which includes specially shaped sealing gaskets on either end and has a rubber liner spanning the area between these sealing gaskets. This rubber sleeve is stretched onto a steel and plastic molding mandrel. This stretching places the rubber liner under tension which reduces the cross-sectional area of the liner and compensates for thermal expansion of the liner during curing. The mandrel/sleeve combination is rotated in order to wind a thermosetting resin impregnated fiber glass roving around the outer circumference of the mandrel/sleeve combination, thus embedding the sleeve in the fiber glass reinforced resin matrix. The thermosetting resin is cured at elevated temperatures, hardening into a rigid coupling with the embedded rubber sleeve integral therewith.

Abstract: Mandrel for making a coupling which coupling comprises a body of fiber glass reinforced plastic which has a rubber sleeve embedded therein. The rubber sleeve is a one piece unit which includes specially shaped sealing gaskets on either end and has a rubber liner spanning the area between these sealing gaskets. This rubber sleeve is stretched onto a steel and plastic molding mandrel. This stretching places the rubber liner under tension which reduces the cross-sectional area of the liner and compensates for thermal expansion of the liner during curing. The mandrel/sleeve combination is rotated in order to wind a thermosetting resin impregnated fiber glass roving around the outer circumference of the mandrel/sleeve combination, thus embedding the sleeve in the fiber glass reinforced resin matrix. The thermosetting resin is cured at elevated temperatures, hardening into a rigid coupling with the embedded rubber sleeve integral therewith.

Abstract: Joints for thermoplastic pipe. The necessity of providing a sealing ring between the socket and spigot of such a joint results in forming a ring groove in the socket and affixing the sealing ring within this ring groove. The present invention contemplates forming a sealing ring groove 6 so configured around a sealing ring 11 with a substantially axially incompressible portion 12 to lock the sealing ring in place and also to enhance the ease of assembly and ability of the thus assembled joint to structurally withstand elevated hydrostatic pressures. Also disclosed is an apparatus 20 and 44 for forming the preferred socket configuration.