The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 07, 1991
Filed:
Sep. 08, 1989
Toshiba Kikai Kabushiki Kaisha, Tokyo, JP;
Abstract
Products having a relatively large thickness such as optical lenses for various industrial applications are molded by an injection molding machine by advancing the screw by operating an injection cylinder for filling metered quantity of a molten resin into a metal mold. The screw is rotated while it is being advanced. A plurality of position setters are provided along the stroke of the screw and their outputs are respectively compared with the output of a screw position detector by using comparators. The outputs of the comparators are used to effect a program control of screw rotation in multistages. According to a modified embodiment, during the filling step effected by screw rotation, the injection speed is varied stepwisely. The injection speed is reduced to zero for a short interval and then increased again. The number of revolutions of the screw, however, is maintained at a constant value until the injection speed is increased again.