Steuervorrichtung zum Verändern der Wanddicke eines Vorformlings in einer Blasform-Maschine

A parison controller of blow molding apparatus for varying the thickness of a parison extruded from an ejection orifice by displacing in an up and down direction a core provided at the ejection orifice of the die of a cross head. The parison controller of blow molding apparatus has a motor through which the core is displaced. It further includes: a rod connected to the core provided at the cross head; a female threaded portion formed on the upper portion of the rod; a rotating rod having a male threaded portion threaded into said female threaded portion; a reduction gear connected to said rotating rod through a thrust bearing; and the motor connected to the reduction gear. Since the core forming the ejection orifice for ejecting the parison is displaced through a motor, a reduction in the size thereof and saving of resources may be achieved and a high quality parison may be obtained as compared with a conventional parison controller which uses a hydraulic system.