| 摘要 |
A continuous tube T is formed by spirally-winding an extruded thermoplastic ribbon R having mating edges which are joined together to form a spiral seam and having at least one reinforcing rib 3 which, when in its spiral wrapped form, projects radially out from the tube. At predetermined lengths, the tube is cut and at the same time the outer surfaces of the tube on each side of the cut are shaped to facilitate handling and interconnecting of pipe section 1 thus formed. At least one end of the pipe has an annular groove 6 at a uniform distance from that end. This groove is formed by cutting a path through each of the radially extending reinforcing ribs intersecting its annular path. An elastomeric O-ring 8 engages the outer surface of the pipe and the axial movement of the O-ring is restrained by the walls of the groove formed by the radially extending reinforcing ribs. An apparatus 30 for cutting the tube at predetermined lengths into pipe sections while the tube is proceeding out of the spirally-winding operation also imparts to the outer surfaces the desired shape as well as cuts the groove for the elastomeric O-ring. This apparatus performs this cutting and shaping operation without interrupting the continuous forming of the tube from the spirally-wound thermoplastic ribbon. |
