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.

Date of Patent:
Nov. 02, 2010

Filed:

Aug. 12, 2008
Applicants:

Tatsumi Makimae, Hiroshima, JP;

Yutaka Fujii, Hiroshima, JP;

Inventors:

Tatsumi Makimae, Hiroshima, JP;

Yutaka Fujii, Hiroshima, JP;

Assignee:
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B23Q 17/00 (2006.01); G01D 1/00 (2006.01); E21B 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A bolt is fastened up to a predetermined snug torque Ts and then the bolt is further fastened by a specified angle θt from a bolt angle corresponding to the snug torque Ts. Herein, in order to obtain excess and deficiency of the fastening angle up to the snug torque Ts, an angle-variation difference between the fastening angle θsb of the bolt at the point where the fastening torque of the bolt has reached the snug torque Ts and a standard angle θsa of the snug torque Ts is calculated. And, addition of this angle-variation difference to a base angle is set as the new specified angle θt to correct the excess and deficiency. Accordingly, variation in a fastening shaft force can be restrained even if the snug torque is set at a relatively high torque in the bolt fastening method using the torque+angle method.


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