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. 28, 1990
Filed:
Sep. 26, 1988
Applicant:
Inventor:
Nobuo Tsuno, Kasugai, JP;
Assignee:
NGK Insulators, Ltd., Nagoya, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F16K / ;
U.S. Cl.
CPC ...
251368 ; 251356 ; 425559 ;
Abstract
A backflow-preventing valve for use in a screw head of a screw injection-molding machine which has an annular shape and comprises a ceramic member is disclosed and a metallic member. At least a surface portion of a backflow-preventing valve which is brought into contact with a material to be injected and a screw groove or a valve seat is constituted by a ceramic material.