| 摘要 |
<p>PURPOSE:To eliminate burr formation on and facilitate manufacture of a pipe fitting, which performs fusion joining upon mounting of a thermoplastic resin pipe where a heating wire is wound at the inner surface of the end face, by forming a spiral groove and a flat part extending in the axial direction in a part of the circumferential direction at the outer surface of the inner cylinder member where heating wire is wound. CONSTITUTION:A die 20 of an injection molding machine is made in two-split structure having a cavity 21, and a spiral convex 23 is formed on the inner surface of the cavity 21, and the area near the split surfaces 22 is formed in flat end face 14. A mandrel 25 is mounted in this cavity 21, and molten resin to form inner cylinder member is injected by the injection molding machine into the gap between the mandrel and cavity 21. Thereby the inner cylinder member 10 of small wall thickness is constructed where a spiral groove 13 is formed in circumferential direction at the outer surface while a flat part 14 is formed in the same plane as the bottom surface of the groove 13 in a position symmetrical about the axis of the groove 13. For this inner cylinder member 10 a heating wire 30 is wound within the groove 13, and molten resin is spouted onto the outer surface of the inner cylinder member 10 to form an outer cylinder member 40. Thus a pipe fitting 1 is provided.</p> |
