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:
Mar. 06, 1990
Filed:
Oct. 14, 1987
Masayuki Hosono, Sohka, JP;
Kenji Waragai, Sohka, JP;
Hirozo Uejo, Ube, JP;
Mitsuru Tokumoto, Ube, JP;
SMS Corporation, Tokyo, JP;
Ube Industries, Ltd., Ube, JP;
Abstract
A double-walled tube assembly has an elongate inner tube of thermoplastic resin, and an elongate extruded outer tube of thermoplastic resin including a plurality of ribs having a constant height longitudinally of the outer tube and extending over the entire length of the outer tube, the ribs projecting toward the center of the outer tube. The ribs have distal ends fused to the outer perpiheral surface of the inner tube over the entire length of the inner and outer tubes. The rib width is from 0.5 to 1.5 mm. To continuously manufacture the double-walled tube assembly, the pre-molded inner tube is fed to an extrusion molding machine having a cross-head die, and thermoplastic resin is extruded from the cross-head die into an elongate outer tube around the inner tube. The inner tube and the extruded outer tube are fed into a sizing die device, in which the outer tube in a softened state is contracted toward the outer peripheral surface of the inner tube until the distal ends of the ribs of the outer tube are fused to the outer peripheral surface of the inner tube.