Motor-driven vertical type injection molding apparatus

U.S. Patent Number: 5393210

Abstract: A motor-driven vertical type injection molding apparatus with stable screw back pressure is provided with a simple structure. A plurality of guide shafts extending in the perpendicular direction are integrally provided in a lower base of an injection unit. A screw holding member is supported on the plurality of guide shafts to be movable in the perpendicular direction. The screw holding member is moved in the perpendicular direction by an injection motor through a ball screw mechanism. A screw extension shaft is integrally connected to the upper end of a screw. The screw extension shaft is supported on the screw holding member to be movable in the axial direction and rotatable. The screw extension shaft and screw are rotated by a measuring motor. In a measuring step, the dead weight of the screw holding member automatically resists the reactive force (screw back pressure) of a molten resin at a screw tip end portion.

Inventors: Kasai; Shozo (Kawasaki, JP), Tohbo; Yozo (Yokohama, JP), Nikaido; Norio (Tsuchiura, JP), Sugawara; Hirofumi (Chichibu, JP)

Assignee: Canon Kabushiki Kaisha (Tokyo, JP)

Application Number: 08/270,804

Issued: 1995-02-28

Expired: 2007-02-28

Classes: 425/145 ; 264/40.4; 425/550; 425/556

Field of search: 425/145,550,556 264/40.4

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