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:
Nov. 12, 2013
Filed:
Jan. 20, 2011
Atsushi Imai, Saitama, JP;
Tooru Imai, Saitama, JP;
Atsushi Imai, Saitama, JP;
Tooru Imai, Saitama, JP;
Other;
Abstract
A bolt-axial-force measuring method and instrument capable of easily and precisely measuring an axial force of a bolt are provided. The bolt is screw-joined and coupled to a piston of a bolt tensioner, and a hydraulic pressure is supplied to its pressure chamber so that the bolt is elongated by applying a tensile force equal to or more than a necessary bolt-fastening force. A nut separating from a fastened member due to the elongation of the bolt is seated again on the fastened member, and the hydraulic pressure in the pressure chamber is discharged to release the tensile force of the bolt. A pressure change of the pressure chamber from which the hydraulic pressure is discharged is detected by a pressure sensor, a point where a change rate of the pressure change detected by a measuring apparatus is suddenly reduced is detected as an inflection point, and a pressure value of the pressure chamber at the inflection point is multiplied by a pressure receiving area of the pressure chamber, whereby the axial force of the bolt is calculated.