Patent ID: 6068810
Filing Date: 2000-05-30
Classification: B29C

Abstract:
The process which comprises:mounting a plasticizing unit having a plasticizing screw within a cylinder;connecting a rotatable and axially movable injection piston to said screw;connecting a first end of a rotatable quill to said piston, wherein said first end has an end face;rotating said quill, piston and screw by a motor means connecting to a second end of said quill;forming a hydraulic cavity by the piston and quill end face and communicating a hydraulic channel with the hydraulic cavity;transferring hydraulic fluid via said hydraulic channel to said hydraulic cavity and thereby moving said piston and screw away from the quill;subsequently moving the screw and piston towards the quill to displace hydraulic fluid out of the hydraulic cavity and into the hydraulic channel and to thereby cause back pressure in the channel;counteracting the back pressure by acting on the second end of the quill; andincluding counteracting said back pressure at least in part by a thrust bearing adjacent the second end of said quill and at least in part by hydraulic pressure acting on the second end of said quill, and wherein said hydraulic pressure acting on the second end of the quill includes lubricating said thrust bearing with hydraulic fluid.