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:
Dec. 03, 1991
Filed:
Feb. 13, 1991
Hidetoshi Yokoi, Setagaya-ku, Tokyo, JP;
Toshikato Okumura, Toyama, JP;
Yukio Nakamura, Kawaguchi, JP;
Noriei Yoneoka, Toda, JP;
Syuiti Hachikawa, Toyama, JP;
Other;
Kabushiki Kaisha Fujikoshi, Toyama, JP;
Abstract
An injection method for making a hole in an injection molded plastic article comprising the steps of filling a mold cavity with a molten plastic and cooling the mold to effect gate seal. A first hole-making punch and a second punch, which are slidably inserted in a bore provided in the mold coinciding with the hole to be made in the article in an axial direction in which a movable mold half is opened and closed, are vibrated with high frequency after gate seal is completed to soften the solidified plastic between the two punches. The punches are then displaced with respect to the bore when the plastic is softened to make the hole. A second injection method comprises the step of making the hole in the molded article by sliding the punches during both dwelling and cooling subsequent to the completion of dwelling after filling the mold with the molten plastic and before gate seal is effected. While said punches are subject to vibration with high frequency or slow reciprocating motion, the side surfaces of the punches are contacted against the hole inner surface to obtain a good cut surface of the hole in the molded article.