| 摘要 |
PURPOSE:To enable a partial variation in thickness without generating a linear protrusion or a steep stepped part on a parison, by a method wherein blocks provided integrally with a thin plate part possessing an overlapping part an covering the inner circumferential surface of a control segment are arranged on both end parts of the control segment. CONSTITUTION:A blow molding machine performs injection molding of a parison through a slit 5 formed between a care 3 arranged on the central part of the lower end of a parison head body 1 and a die 2 provided on the outer circumference of the core 3. An annular recessed groove 16 is provided on a surface part of the slit 5 of the lower end of the die 2 in the direction meeting at about right angles with the surface part, and control segments 17, 18 constituted by performing pin 23 connection of end parts of circular-arc segment between them so that it may bend freely in a radial direction along the recessed groove 16 are arranged in a necessary position of he inside of the recessed groove 16. Then a block 21 provided integrally with thin plate parts 22a, 22b covering the inner circumferential surface of the control segments respectively and possessing a wedgy tip part forming the smooth inner circumferential surface through mutual overlapping is fitted in on both the other end side positions of the control segments 17, 18 in the recessed groove 16 in the die 2 for adherence. |
