| 摘要 |
PURPOSE:To reduce the trouble and time for pierce-working of a pipe, by inserting a center die having a long hole on the outside face, into a pipe, and piercing the edge into the long hole from the outside through the pipe. CONSTITUTION:At first, a pipe 17 which requires piercing is inserted through a center die 10 by providing a clearance, and the pipe 17 is pinched by a punch 14 and a die 13 from both upper and lower parts and is fixed. Subsequently, an edge 16 is dropped vertically through a long hole 15 of the punch 14, is made to pass through the pipe 17, and is pierced to the inside of a long hole 12 of the center die 10. Thereafter, the edge 16 is drawn out to the upper part, the punch 14 and the die 13 are removed, the pipe 17 is floated upward from the center die 10, meshing of a return part 19a against the long hole 12 is detached, and the pipe 17 is then drawn out. In this way, the pipe 17 having a notch hole 19 is mass-produced at a low cost easily and in a short time, without using a milling machine, and also without deforming the pipe 17. |
