| 摘要 |
PURPOSE:To enable continuously molding of a synthetic resin pipe whose external circumference possesses a spiral reinforcing line and inside of a pipe wall is flat, by a method wherein a molding center core and a line material made of semimolten synthetic resin are wound spirally round a molding shaft in order through cooperative operation with a synchronously rotating auxiliary shaft. CONSTITUTION:A molding center core 48 in an endless state is wound spirally round molding shafts 14 each, a halfway part of the endless molding center core 48 is wound round auxiliary shafts 29 each spirally in the reverse direction through a V belt 43 by slackening downward the halfway part of the endless molding center core 48 and twist of the center core 48 is prevented. Then a line material 1 is wound round the center core 48, a spiral reinforcing line B is formed with a U-shaped part 1a and a pipe wall A whose inside is flat is formed of a long and short side parts 1b, 1c which are superposed upon each other. Then cut grooves C is formed in order by piercing the top of the reinforcing line B with a cutter 52, the center core 48 is pulled off from the inside of the reinforcing line B through the cut grooves C and returned to the starting part of winding. Then a semimolten belt-like material 2 is integrated with the cut groove C by entering a part of the same into the cut groove C. With this construction, the inside is made flat and soft flexibility, low flow path resistance and high crushing-resistant strength can be obtained in a synthetic resin pipe. |
