| 摘要 |
<p>PURPOSE:To eliminate the possibility of stopping the flow of sewage inside a joint by eliminating the accumulation of impurities by making the stopper portion at the receiving end of the joint at right angles with its inner surface, and also making the height of the stopper portion substantially the same as the thickness of a pipe to be inserted through such an arrangement wherein the differently leveled portion which becomes a stopper portion is formed substantially at right angles by preliminary forming, and after that the joint is processed by blow forming. CONSTITUTION:A preliminary receiving mouth 12 is formed at the end of a synthetic resin pipe 11. The inner circumference of said receiving mouth 12 is tapered from its end to its inner portion, and its differently leveled portion 13 which becomes a stopper portion of a pipe to be inserted is formed substantially at right angles. Said receiving mouth 12 is softened by heating it up to 90-130 deg.C and an inner metal mold 15 is inserted into there and airtightness is maintained therein. Said receiving mouth 12 is caused to inflate until it is brought to tightly contact with an outer metal mold by injecting pressurized fluid of about 10kg/cm<2> such as compressed air, etc. and then it is cooled while pressure is maintained, and as metal molds are removed, blow forming completes. When an inserting pipe 19 is inserted into a diameter expanded receiving mouth 2 thus formed, the inner surface of the inserted pipe 19 becomes the same level as that of the pipe 11.</p> |
