ELONGATION DRIVE DEVICE OF STRETCH ROD IN STRETCH BLOW MOLDING MACHINE AND BOTTOM-TYPE LIFTING DRIVE DEVICE

摘要

Improvement of simplicity and durability of a stretch rod extending device and a bottom mold lifting device, equipped on a stretch blow molding machine, is achieved by applying a combination of a magnetic screw shaft and a magnetic nut member, which is able to convert rotary - linear movement smoothly without contact. The nut member and the screw shaft of the extending device 6 and lifting device 30 comprise a magnetic nut member 65, 116 and a magnetic screw shaft 66, 117, having spiral N magnetic pole and S magnetic pole alternately provided on inner peripheral surface of a cylindrical member and outer peripheral surface of a shaft at a same regular pitch. The magnetic screw shaft is inserted into the plunger 61, 115, having the magnetic nut member equipped inside with keeping required clearance so as to match the magnetic pole to oppose the magnetic nut member at the same poles each other.