| 摘要 |
The present invention is carried out to supply a small sized and lightweight steel pipe bending apparatus so as to bring to construction sites, so as to keep thinning a thickness of the pipe at lower level and so as to obtain the pipe with a desired bending radius. The following apparatus realizes above-mentioned objectives of the present invention. A pipe bending apparatus comprises; a heating means to heat a steel pipe circularly around an center axis of the pipe, a cooling means to cool the heated portion of the pipe circularly around the center axis of the pipe, a tensile force applying means to apply the tensile force on points of application which are located in the opposite directions from the circular heated portion, a variable controlling means to control the tensile force variably, a transfer means to transfer the heated portion and the steel pipe relatively to the heating means and the cooling means in the direction of the axis of the steel pipe and a controlling means to control a velocity of the transfer.
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