| 摘要 |
PURPOSE:To facilitate the drawing of a mandrel from a pipe by constituting a mandrel with the segment forming the taper in the line direction on the inner face and the main shaft the segment inside movably by forming the taper conforming to this taper on the outer face. CONSTITUTION:A pipe blank 7 is held by a manipulator 15, a carrier cylinder 18 is extended to move the manipulator 15 to the downstream side, the tip of the mandrel 9 projecting from the blank 7 is inserted between the dies 2, 3 of a forging press 6 and the tip of the blank 7 is set between the dies 2, 3 by advancing the manipulater 15 further. The pipe blank 7 is then formed by the dies 2, 3. After completion of the pipe making the mandrel 9 is easily drawn out of the pipe by contracting the outer diameter of the mandrel 9 by conforming the taper 30 of a main shaft 31 to the taper 34 of a segment 37 by contracting the cylinder 33 of the mandrel 9.
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