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:
Sep. 14, 2010
Filed:
Jul. 29, 2004
Takefumi Nakako, Amagasaki, JP;
Takeyuki Yoshida, Amagasaki, JP;
Shigeo Matsubara, Chiyoda-ku, JP;
Toshiharu Kittaka, Chuo-ku, JP;
Hiroki Kanazawa, Chuo-ku, JP;
Takefumi Nakako, Amagasaki, JP;
Takeyuki Yoshida, Amagasaki, JP;
Shigeo Matsubara, Chiyoda-ku, JP;
Toshiharu Kittaka, Chuo-ku, JP;
Hiroki Kanazawa, Chuo-ku, JP;
Nisshin Steel Co., Ltd., Tokyo, JP;
Abstract
A high-strength steel pipe rockbolt has an expansive rockbolt main body prepared by processing a high-strength steel sheet of 1.8-2.3 mm in thickness with a tensile strength of 490-640 N/mmand an elongation of 20% or more into a welded pipe and roll-forming the welded pipe into a shaped pipe having one or more concavities extending along an axial direction. Use of the high-strength steel sheet ensures sufficient strength of the shaped pipe regardless of a decrease in thickness. The thin welded pipe is also advantageous in resistance to cracking caused by accumulation of strains introduced during roll-forming, swaging both ends of the welded pipe and hydraulic expansion. Moreover, expansive deformation of the shaped pipe is initiated by injection of a pressurized fluid at a low pressure, so that the expansive deformation is completed in a short time period with an improved working efficiency.