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:
Aug. 31, 1999
Filed:
Aug. 29, 1997
Nissei Plastic Industrial Co., Ltd., Nagano-ken, JP;
Abstract
A screw head device 1 for an injection molding machine includes a ring valve 3 set on a stem portion 2 of a screw head for movement in back and forth direction and for defining a rear side resin passage Rr between its own inner peripheral surface and the stem portion 2, a front side resin passage Rf extending axially and communicated with the rear side resin passage Rr, and a surge preventing mechanism, in which the front end of a screw main body Sm acts as a valve seat for mating with the rear end face of the ring valve 3. At a rear side of the head portion 4, a spacer guide 6 is provided. The outer peripheral surface 6s of the spacer guide 6 is located radially inside of the outer peripheral portion 4s of the head portions end racially outside of the bottom portion Rfd of the front side resin passage Rf. A front ring spacer 7 formed of a ceramic material, such as a boron alloy cermet, and having flat front and rear end faces 7f and 7r is set on the spacer guide 6 with mating the rear end face 7r with the ring valve 3. By this, the front ring spacer 7 is interposed between the 20 head portion 4 and the ring valve 3 to avoid wearing of the ring valve 3 by unevenness of the head portion.