Patent ID: 8234936
Filing Date: 2012-08-07
Classification: B25B

Abstract:
1. A torque wrench comprising: a shaft-like strain body having a leading end coupled with a replaceable tightening portion; pairs of first and second distortion sensors for measuring an amount of distortion of the strain body, one of the first distortion sensors and one of the second distortion sensors being arranged on one of opposite sides in a tightening force application direction of the strain body, at spaced points in an axial direction of the strain body, the other first distortion sensor and the other second distortion sensor being arranged on the other side in the tightening force application direction of the strain body, at spaced points in the axial direction of the strain body; a housing comprising: a front side cover part in a tubular shape adapted to receive the leading end of the strain body, a leading endface of the front side cover part being provided with a hole for receiving a proximal end of the tightening portion; and a back side grip part in a tubular shape adapted to receive a proximal end of the strain body, the back side grip part being provided therein with a shaft extending in a direction orthogonal to the tightening force application direction and through the strain body; a torque computation section for performing a computation of a tightening torque T while correcting an error due to a change in a point on the housing where a tightening force is applied by a user of the torque wrench, at least based on measurement results of the first and second distortion sensors; and an output portion for outputting at least a result of the computation performed in the torque computation section as a tightening torque measurement value, wherein a rear end of the strain body is fixed to the back side grip part to prevent movement of the rear end of the strain body in the tightening force application direction.