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:
Mar. 08, 2011
Filed:
Oct. 01, 2009
Keiichi Nakamura, Wakayama, JP;
Takahiro Hamamoto, Wakayama, JP;
Masaaki Sugino, Nishinomiya, JP;
Suguru Yamaguchi, Amagasaki, JP;
Keiichi Nakamura, Wakayama, JP;
Takahiro Hamamoto, Wakayama, JP;
Masaaki Sugino, Nishinomiya, JP;
Suguru Yamaguchi, Amagasaki, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A threaded joint for steel pipes constituted by a pin having male threads and a box having female threads is improved with respect to ease of insertion of the pin and galling resistance of the threaded portions. The stabbing flanks of the threads in a complete thread portion of one of the pin and a box has a two-step stabbing shape having a chamfer. The two-step stabbing shape has a stabbing flank angle α of 5-45° and a chamfer angle β of 20-60°. The ratio h/H of the chamfer height h to the thread height H of the pin is 0.25-0.50, or the ratio of the cross-sectional area of the chamfered portion to the overall cross-sectional area of the stabbing flank is made at least a value corresponding to a chamfer height ratio h/H of 0.25 and at most a value corresponding to a chamfer height ratio of 0.50.