Patent ID: 6698298
Filing Date: 2004-03-02
Classification: B25B

Abstract:
A torque wrench for additional tightening inspection for tightening a bolt in a tightened state, comprising:a wrench body; torque detecting means for detecting a torque in tightening said bolt, said torque detecting means being arranged in the wrench body; rotation angle detecting means for detecting a rotation angle of the wrench body, said rotation angle detecting means being arranged in said wrench body; first arithmetic means for assuming a torque gradient line in a rotating state of said bolt based on input information acquired in a stable domain after rotation of said bolt in the tightened state by the wrench body and a referential torsion characteristic gradient line set in advance, said input information being torque information detected by said torque detecting means and the rotation angle detected by said rotation angle detecting means; second arithmetic means for assuming a torque gradient line in a stationary state of said bolt obtained from said input information before the rotation of said bolt; and third arithmetic means for determining an intersection between the torque gradient line in the rotating state obtained by said first arithmetic means and the torque gradient line in the stationary state obtained by said second arithmetic means, and determining a torque value at the intersection as a torque measurement.