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. 01, 2016
Filed:
Dec. 10, 2013
Atlas Copco Industrial Technique Ab, Stockholm, SE;
Erik Vilhelm Persson, Solna, SE;
Arne Torgny Roloff, Stockholm, SE;
ATLAS COPCO INDUSTRIAL TECHNIQUE AB, Stockholm, SE;
Abstract
In an apparatus and a method of evaluating a clamp force (F) in a threaded joint between a bolt and a matching threaded piece during a tightening operation, a torque (T) provided to the joint is continuously measured and ultra-sonic pulses are simultaneously induced into the bolt such that a time of flight (TOF) of the pulses in the bolt is measured. In response to an increase of the measured torque (T) an increase rate (dT/dα) of the torque (T) is determined, from which an initial rotation angle (α) where the torque (T) starts to increase due to bolt deformation is determined. An increase rate (dTOF/dα) of the time of flight (TOF) is also determined. A total increase of the time of flight (ΔTOF) during the tightening operation is then determined based on the initial rotation angle (α) and the increase rate (dTOF/dα) of the time of flight (TOF).