| 摘要 |
PURPOSE:To bring the position of contactors of a high-frequency welding device to just before squeeze rollers or the same position as said rollers and to reduce the defective length of a top end by inserting a stationary holder for holding said contactors to the inside of a half-formed pipe through the aperture just prior to closing and bringing the contactors into press contact with the inside wall at the aperture edge. CONSTITUTION:A welding device is installed between guide rolls 9 and squeeze rolls 10 and a stationary holder 7 is passed through an aperture (b) and is extended to near the squeeze rolls 10, 11 to support a movable block 2, a pressure spring 5, etc. Both electrode contactors at the end of the block 2 are then brought into press contact with the inside wall at both side edges of the aperture and high frequency current is passed through the point V to heat the shortest passage thereof. On the other hand, the rolls 10 press the pipe (a) from the right and left outsides to accomplish resistance welding. The distance between the contactors 1 and the point V is thus considerably shortened by which the defective part of the top end of welding is reduced and the yield is improved. |
