| 摘要 |
PURPOSE:To obtain a synthetic resin pipe, which is of precision and a well-regulated form by preventing a reinforcing line from getting out of shape, by a method wherein a spiral reinforcing line is molded simultaneously with a pipe body by an endless molding core mold wound spirally on a molding shaft and an annular press mold is wound round the outside. CONSTITUTION:A semimolten line material 10 to be extruded in a state of a flat plate through a molding die 13 of an extrusion molding device 12 is wound round on driving and rotating molded shafts 5. In this instance, as a molding core mold 14 is wound on the molding shafts 5 beforehand, the line material 10 is molding so that the same forms a U-shaped part 10a, long side part 10b and short side part 10c. On the other hand, as an annular press mold 16a is wound round at two positions on a space between reinforcing lines B of a synthetic resin pipe A, which controls the shape losing of the U-shaped part 10a to be molded on the molding shaft 5. Then the top of the reinforcing line B of the synthetic resin pipe A is pierced with a cutter 18, a cut groove C is formed continuously and then the core mold 14 pulled out from the inside of the reinforcing line B through the cut groove C is returned to a starting end part for winding up.
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