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. 19, 1998
Filed:
Aug. 22, 1996
Naotaka Kawaguchi, Numazu, JP;
Kyoichi Sasaki, Numazu, JP;
Toshiba Kikai Kabushiki Kaisha, Tokyo-to, JP;
Abstract
A barrel for a twin screw extruder having a pair of helical screws has a barrel body provided with a pair of partly overlapping cylindrical bores, and the pair of helical screws are rotatably supported in the pair of cylindrical bores of the barrel to mix and extrude a molding material. An abrasion resistant layer is formed in at least portions of the surfaces of the pair of cylindrical bores extending in the vicinity of at least one of the two lines of intersection of the pair of partly overlapping cylindrical bores. The abrasion resistance of the abrasion resistant layer has a maximum in a portion thereof around the line of intersection of the pair of cylindrical bores and decreases gradually with distance from the line of intersection. The abrasion resistant layer is formed by depositing a material containing a hard substance by build-up welding, and the hard substance content of the material in the abrasion resistant layer is varied with distance from the line of intersection. The abrasion resistant layer is formed by depositing a material consisting of a corrosion resistant base alloy and a hard substance. The abrasion resistant layer may be formed on a corrosion resistant layer formed over the entire surfaces of the pair of cylindrical bores.