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:
Dec. 07, 2021
Filed:
Sep. 02, 2016
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Jun Nitta, Tokyo, JP;
Shigeru Yonemura, Tokyo, JP;
Satoshi Shirakami, Tokyo, JP;
Takashi Yasutomi, Tokyo, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
Abstract
There is provided a hole widening method including a preparing process of preparing a forming tool which has a diameter-increasing portion increasing in diameter from a front end side toward a rear end side and a line-shaped projection formed to protrude outward from a surface of the diameter-increasing portion, and a workpiece in which a pilot hole is formed; and a hole widening process of successively widening the pilot hole by pushing the forming tool into the pilot hole such that the line-shaped projection of the forming tool comes into point contact with a part of a circumferential edge portion of the pilot hole in the workpiece two times or more, and forming a stretched flange.