| 摘要 |
PURPOSE:To eliminate forming of a ferrule part and to improve material yield in die drawing of a tube by making claws of plural chuck pieces fitted to the tapered part of a tension rod bite the inner face of the tube by drawing and making them correspond to the change of inner diameter. CONSTITUTION:Plural chuck pieces 11 joined by elastic members 14 are fitted to the tapered tip 12A of the tension rod 12 of a tube expander. By inserting the rod 12 into inner diameter of the tube 5 and pulling it, claws 13 of the chuck pieces 11 bite the inner face of the tube. As the tube 5 passes through a die hole 3, the chuck pieces 11 slide on the tapered part 12A, and conform to the change of inner diameter. As a ferrule part chucked to the tube is not formed, the process is simplified and the yield of tube material can be improved. |
