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:
Oct. 13, 1981
Filed:
Nov. 23, 1979
Applicant:
Inventors:
Assignee:
Nippon Steel Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B21D / ;
U.S. Cl.
CPC ...
72 51 ; 72368 ; 72389 ; 72473 ; 72478 ;
Abstract
Rolled steel plate is press-fabricated into cylindrical UO pipe with a large wall thickness, by the steps of crimping, U-ing and O-ing. In the U-ing process, a collapsible U-ing punch, including a center block carrying paired side punches on both sides and a bottom punch at the bottom, is used. The U-ing punch insures that the O-shaped workpiece has the desired butt gap by decreasing the ratio of its height to its width when the gap proves to be smaller than the desired butt edge gap, and vice versa when the gap proves to be larger than the desired butt edge gap.