| 摘要 |
PURPOSE:To manufacture joints excellent in dimensional accuracy and mass productivity by forming a pipe by cold or warm forging and cutting screw by cutting work. CONSTITUTION:A pipe is inserted into a die that has expanded upper half, a tapered part and a small diameter part which is nearly the same in diameter with a pipe 20. An end of it is expanded by pressing in a punch at cold or warm state, and then another end is expanded similarly to make a member (a). Next, an expanded part 21 of the member (a) is inserted into another die, and a punch is pressed in at cold or warm state to make an expanded part 24 in which the expanded part 21 is thickened. The expanded part 21 of another end is then thickened to make a member (b). An annular projection 27 called a dowel is formed in this member (b) using a another die, and a screw 28 is provided by cutting on the outer periphery of expanded parts 26, 26 of the member (c) thus obtained to make a socket S. |
