PURPOSE: To enable the production of a bent tube of a good quality, by locating an absorptive solid board made tape wound in a spiral at the inside of a resin tube and by enabling said work to be freely bent while the resin is not solidified.
CONSTITUTION: A spiral gap 4 is provided between rounds of a winding 1 formed by winding in a piral a tape made of a solid and absorptive board such as pulp papers and cardboards. A waterproof film 2 made of an impermeable material such as polyethylene is closely wound therearound. A resin tube 3 is formed such that a tape made of thermoplastic polyester resin and glass fibre is compactly wound around said work again. A columned core mold 5 made of a flexible rubber, etc., is inserted into the inside of the board winding, the board being expanded with water while thermoplastic resin is not solidified. As a result, a gap between the core mold and the waterproof film is filled with the board, the resin tube being then bent in the axial direction togetherwith the core mold. The bent tube can thus be produced.
SHIRAKAWA TOSHIAKI
INAI TOSHIMI
ISHIDA HIROSHI
SHIMIZU TAKASHI
| JPS4837139A | 1973-06-01 | |||
| JPS4710548A | ||||
| JPS5218744A | 1977-02-12 |