Mold for making composite tube couplings

Abstract

An apparatus is disclosed for making a composite tube with end couplings. The composite tube is made utilizing known equipment and process to form spaced end sections and a central section having an inner corrugated portion and surrounding portion bonded to at least certain crests of the corrugations. A spaced pair of generally cylindrical end couplings are formed by sequentially telescoping the end sections over an internal cylindrically contoured die part and continuing the telescoping until an inner surface of the telescoped end section engages at least three circumferentially spaced fingers to locate the telescoped end section in concentric relationship with the core part. An external die part is positioned in spaced concentric relationship around the telescoped end section, the external die part having an inner surface contoured to the desired external configuration of a coupling being formed. A heat softened thermoplastic material is injected into the space between the die inner surface and the core to form a coupling. As the thermoplastic material is injected it is maintained at a sufficiently elevated temperature to effect a bonding between the coupling and the telescoped end section.