| 摘要 |
<p>PROBLEM TO BE SOLVED: To wind, at winding a heating wire into a groove, the heating wire at constant pitch only by pushing to prevent projection of the heating wire without deteriorating inserting performance of the heating wire to the groove, in a mat of thermoplastic resin which is used for molding a heat fusion joint of a saddle system such as saddle joint and service tee joint and in which the heating wire is wind in a spiral shape. SOLUTION: In an inner peripheral side of the groove 14 formed into spiral shape, a throat part 17 having narrower width than a diameter of the heating wore 2 is formed by forming a projection 16 to a partition wall, and a guide 18 is formed which is inclined toward an opening enlarging from the throat part 17. Winding of the heating wire 2 is carried out such that the heating wire 2 is pushed to the guide 18 and pushed into the throat part 17, thereby to be forcedly fitted to a bottom of the groove. The heating wire 2 fitted to the bottom of the groove is prevented, at it throat part 17, from projecting, and a lateral moving is restricted to enable winding at constant pitch.</p> |
