| 摘要 |
PURPOSE:To eliminate the ragged strain of a pipe joint developed during its manufacturing and consequently obtain the pipe joint conforming to the normal shape and dimensions by a method wherein the intermediate portion of the pipe joint is softened by heating and controlled the shape utilizing the shrinkage of diameter developed by softening with a core. CONSTITUTION:The end pipe 7 of a pipe joint 1 is held on a pivoting power source 15 side, while the spigot part 3 of the pipe joint 1 is held with a pivoting socket 3. The intermediate portion 4 of the pipe joint 1 is softened by being heated with a heat source 17 under the state just mentioned above, resulting in causing the shrinkage of its diameter. After that, the pipe joint 1 is released and shifted to a core 13, the shape and dimensions of which conforms to those of the normal inner surface of the intermediate portion 4 of the pipe joint 1. The core 13 is inserted from the end pipe 7 side of the pipe joint 1 so as to abut the intermediate portion 4 against the core 13 by pushing the spigot part 3 with a press plate 19 in order to control the shape and dimensions of the inner surface of the intermediate portion 4. Next, the pipe joint is sildified by cooling. After the cooling of the pipe joint, the press plate 19 is separated from the pipe joint. Finally, the pipe joint is released from the core 13 by pushing up a stripper plate 20 (not shown in fig.) attached on the core 13. The pipe joint is used by fitting a packing 9 (not shown in fig.) in a grooved part 8. |
