| 摘要 |
PURPOSE:To easily form a synthetic resin drain pipe of diverse diameters by a method in which a coupling projection is provided on one end of a synthetic resin strip material, a groove to be coupled is provided in the other end, while the strip material is twisted spirally, and the coupling projection is connected with the groove to be coupled. CONSTITUTION:A coupling projection 2 is provided over the whole length on one end of the outside of a long synthetic resin strip plate 1, and a coupling groove 3 consisting of tiers and a groove 6 is provided over whole length on the other side of the outside of the plate 1. The strip plate is twisted spirally to form a cylinder, the adjacent coupling projection 2 is connected with the adjacent coupling groove 3, and a rib 4 is spirally coupled over the whole length of the coupled portion to a projected line 5 on the surface of the outside of the coupled portion. Drain pipes of various diameters can be obtained without the use of a large number of molds. |
