| 摘要 |
PURPOSE:To shorten the straight pipe length at the pipe end and to surely prevent the crushing of the pipe end part by pressure-connecting the engaging member with its fitting to the inner face of the pipe end in adequate length in case of bending the pipe material which clamps the pipe end by pressing in the axial direction with heating the one part thereof. CONSTITUTION:A pipe material 1 is bent with pressing it in the axial direction P with heating by high frequency heating coil 3 one part of the pipe material 1 in the state of clamping the pipe 1 end by clamping device 5 and giving the pressure to the pipe 1 by cylinder 9. In this case, a crush preventing jig 12 is inserted into the inner face of the pipe end in adequate length, the diameter of a shoe 15 is expanded by pulling a taper core rod 14 with hydraulic cylinder 17 and pressure-connected to the inner face of the pipe material 1. With this jig 12 the straight pipe length at the pipe end can be shortened and the crushing of the pipe end part is surely prevented.
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