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. 17, 2013
Filed:
Jul. 08, 2011
Norikazu Tezuka, Takasago, JP;
Kazuharu Hirokawa, Takasago, JP;
Keisuke Ihara, Takasago, JP;
Kei Osawa, Takasago, JP;
Hiroshi Ishikawa, Takasago, JP;
Taiji Torigoe, Takasago, JP;
Ryuichi Yamamoto, Takasago, JP;
Yukihiro Hashimoto, Takasago, JP;
Nobuyuki Izutsu, Takasago, JP;
Koji Takahashi, Takasago, JP;
Norikazu Tezuka, Takasago, JP;
Kazuharu Hirokawa, Takasago, JP;
Keisuke Ihara, Takasago, JP;
Kei Osawa, Takasago, JP;
Hiroshi Ishikawa, Takasago, JP;
Taiji Torigoe, Takasago, JP;
Ryuichi Yamamoto, Takasago, JP;
Yukihiro Hashimoto, Takasago, JP;
Nobuyuki Izutsu, Takasago, JP;
Koji Takahashi, Takasago, JP;
Mitsubishi Heavy Industries, Tokyo, JP;
Abstract
A bolt has a male screw with a surface hardening portion that has an increased surface hardness and that is applied with a compressive residual stress. The male screw is formed by cutting the bolt, and performing a process to provide at least on the surface of the male screw of the bolt the surface hardening portion that has increased hardness and that is applied with a compressive residual stress. As a result, the fatigue resistance of the male screw is improved and the bolt is effective for use in a portion where the male screw is subject to a repetitive stress.