Patent ID: 7832286
Filing Date: 2010-11-16
Classification: B25B

Abstract:
1. A torque wrench, comprising: a tightening unit; a housing; an axis; a strain body including a tip part for replaceably connecting the tightening unit thereto; a setting unit for selectively inputting a type of the tightening unit thereto; a distortion sensor for detecting a distorted amount of the strain body corresponding to a tightening force of the tightening unit; a torque computation unit, in which a plurality of predetermined torque reference values required for computing tightening torques of different types of tightening units and corresponding to effective lengths of the tightening units have been prepared in advance, for computing the tightening torque T=(R×D) based on an appropriate one value R of the torque reference values that corresponds to the type of the tightening unit and a detection result D of the distortion sensor; an output unit for outputting at least a computation result by the torque computation unit as a tightening torque measurement value; and a memory unit, externally connected to a device incorporating the torque computation unit, for storing therein the predetermined torque reference values for outputting to the computation unit, wherein said torque reference value R is determined by R=T0/D0, in which T0 is a tightening torque at a preset reference weight, and D0 is an output value of said distortion sensor at said preset reference weight; wherein the housing includes: a front side cover part in a cylindrical shape for accommodating the tip part of the strain body, a tip face thereof having a hole for inserting a base end part of the tightening unit; and a back side grip part in a cylindrical shape for accommodating a base end part of the strain body, wherein the axis is disposed inside the back side grip part and extends in a direction orthogonal to the tightening force of the tightening unit so as to pass through the strain body, and wherein the back side grip part is capable of tilting slightly with respect to the front side cover part with the axis rotatably supporting the back side grip part.