| 摘要 |
PURPOSE:To form a straight pipe in good-shaped bent pipe by straightening a pipe bend deformation part without any defect, by inserting the insertion member that almost equal outer diameter correction member is linked with a fine linking member into the straight pipe inner hole which is restrained to a bending die and by drawing out the insertion member after the pipe bend. CONSTITUTION:A straight pipe 3 is fastened to a bending die 1 and bound with a die 2. The core metal 4 composed of the insertion member 4a that the straightening member 4b of the globular body, etc., having the outer diameter about equal to the inner diameter of the straight pipe 3 is inserted into the inner hole of the straight pipe 3. The straight pipe 3 is bent in the prescribed curvature by pulling around a pressure die 6 along the bending die 1 curved face. Thereafter, the straightening member 4b is pulled out by drawing the insertion member 4a to form the pipe material deformed inner part in the circular inner hole having no such defect as wrinkle, etc. This chain 5 may be formed in a flexible body or oscillatable rigid body.
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