PURPOSE: To easily and efficiently execute the knock-out.
CONSTITUTION: A square pipe stock 1a is deep-drawn with a truncated square conical male die 8 and a female die corresponding to this male die to manufacture a tapered square pipe 1. One pair of stoppers 9 faced to the upper part of the male die 8 are arranged so as to be slidably in the horizontal direction. The stopper 9 is energized to the outer part of the male die 8 with a spring 13 and projecting from the outer peripheral surface of the male die 8 in the ordinary condition. When the female die descended at the time of squeezing, the inclined inner surface of the female die is brought into contact with the tip of each stopper 9, and each stopper 9 is shifted to the center direction of the male die 8 by the component of force in the horizontal direction. At the time of executing the squeezing formation, as ordinarily the tapered square pipe 1 is press-stuck to the inner surface of the female die, at the time of using the female die, the tapered square pipe 1 ascend together with the female die, but the ascending is stopped by hitting to the stopper 9, and the tapered square pipe is separated from the inner surface of the female die. In such a way, the knock-out is automatically executed in the press movement without needing a special process for knock-out.
MIYATA TSUTOMU
TOMITA MASANORI
