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. 05, 1986
Filed:
Aug. 07, 1984
Kazuo Watanabe, Kitakyushu, JP;
Hiromi Seki, Kitakyushu, JP;
Kenji Yamada, Kitakyushu, JP;
Yoshito Tsuyama, Tokyo, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
First, a rectangular metal plate having thinner and thicker portions corresponding to a lighter-wall portion and heavier-wall portion of a pipe to be manufactured is prepared. Before bending the plate until both edges thereof meet to form a tubular piece, the plate width is adjusted by cutting off part of the thinner portion so that the desired peripheral lengths are attained in both lighter- and heavier-wall portions of the pipe. The width-adjusted plate is then bent until both edges are butted together to form a tubular piece. By butt-welding the adjoining edges, a metal pipe with longitudinally differentiated wall thickness is obtained.