| 摘要 |
PURPOSE:To shorten the time for working and to improve its productivity of a titled device by forming and cutting the end face of a main pipe that is joined to a head pipe to a specified shape, keeping the end face of a reinforcing member which is joined with the two open state and resistance-welding the end faces. CONSTITUTION:The whole or joined end face 8 of the main pipe 7 joined to the head pipe 9 is formed to an ellipse and cut straight or obliquely in two steps, and joined end faces 11, 12 of a reinforcing member 10 are slightly opened. The minor axis of the pipe 7 is made smaller than the diameter of the pipe 9, and a projection 20 is provided at the contact 18. The pipe 9 and the end of the member 10, the pipe 9 and the end face of the pipe 7, and the pipe 7 and the end 11 of the member 10 are joined respectively by projection-welding or spot-welding. At this time, upper and lower electrodes of the welding device are shaped to permit easy attaching of pipes 9, 7 and butt welding is performed. Thus, a bicycle head of high quality can be obtained by simple working and in a short joining time. |
