US 5,393,210 AGranted

Motor-driven vertical type injection molding apparatus

AssigneeCanon Kabushiki Kaisha

InventorsShozo Kasai, Yozo Tohbo, Norio Nikaido, Hirofumi Sugawara

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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.

Claims6

Dependent claims

A vertical injection molding apparatus, comprising:

a heating barrel for heating resin material to be injected, said heating barrel being connected to a fixed platen for supporting a stationary die;
a screw, disposed within said heating barrel, for injecting molten resin material into a mold cavity;
a screw holding member for rotatably holding said screw, said screw holding member and said screw having a combined weight so as to exert back pressure to the resin material in said heating barrel while moving together in a rectilinear direction;
measurement means for measuring the amount of said molten resin material in said heating barrel by operating said screw;
a guide frame for guiding up and down movement of said screw holding member;
means for coupling said measurement means to said screw;
and
injection means for generating a driving force on said screw, said injection means comprising a motor for injection and means connected to said screw holding member for converting rotation of said motor into rectilinear movement of said screw holding member.

5 more elements

Dependencies are inferred from the claim text.