| 摘要 |
PURPOSE:To improve the efficiency in working, etc., by providing the outer split die and inner split die having a screw forming part moving them in the ladial direction respectively via a cam means as well and arranging the lift mechanism of the inner and outer dies and the rotary means of the inner die. CONSTITUTION:The outer die 8 having a screw projecting part 8A is held by an outer die holder 4, the outer die 8 is divided into outer split dies 9 which are respectively made movable freely in the radial direction. An inner die 23 is composed of plural inner split dies 24 which are made movable freely in the radial direction for the inner die cradle 21 respectively, and on the outer peripheral face of the inner die 23, the screw recessed part 23A corresponding to the screw projecting part 8A of the outer die 8 is formed. A screw step difference is eliminated by vertically moving the inner die 23 and outer die 8 by the crank shaft of a transfer press, etc., and rotating the inner die 8 around the axial line of the body 16 to be worked. Since the screw forming can be performed with one time of the vertical movement of a press, the working efficiency is improved and simultaneously the quality of screws is improved as well.
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