US 2002/0152820 A1Published application

Torque wrench for further tightening inspection

AssigneeTohnichi Mfg. Co., Ltd.

InventorsHiroshi Tsuji, Nobuyoshi Kobayashi

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Abstract

To provide a torque wrench for additional tightening inspection which corrects an error resulting from the rotation of the torque wrench before the rotation of an inspection bolt so that a precise torque value can be measured by simply tightening the tightening bolt additionally. When the inspection bolt is tightened, the rotation of the wrench is detected before the rotation of the bolt due to the torsion of the wrench itself. The intersection P between a torque gradient line M obtained at that time and a torque gradient line N of a rotating state after the rotation of the bolt makes a measuring point. The torque value at this intersection P is determined to obtain a torque measurement. Here, the torque gradient line N is obtained by connecting several points each corresponding to a torque value 90% the torque value TA at the intersection PA with a referential torsional torque gradient line L.

Claims6

Dependent claims

A torque wrench for additional tightening inspection for tightening a bolt in a tightened state, comprising:

torque detecting means for detecting a torque in tightening said bolt, said torque detecting means being arranged in a wrench body;
rotation angle detecting means for detecting a rotation angle of the torque wrench, 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 the rotation of said bolt and a referential torsion characteristic gradient line set in advance, with torque information detected by said torque detecting means and the rotation angle detected by said rotation angle detecting means as said input information;
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.

3 more elements

A torque wrench for additional tightening inspection for tightening a bolt in a tightened state, comprising:

torque detecting means for detecting a torque in tightening said bolt, said torque detecting means being arranged in a wrench body;
rotation angle detecting means for detecting a rotation angle of the torque wrench, 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 the rotation of said bolt and a referential torsion characteristic gradient line set in advance, with torque information detected by said torque detecting means and the rotation angle detected by said rotation angle detecting means as said input information;
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, as a torque measurement, a torque value at an intersection between the torque gradient line in the rotating state of said bolt obtained by said first arithmetic means and the referential torsion characteristic gradient line when a number of pieces of said input information for arithmetic in said second arithmetic means falls below a number set in advance.

3 more elements

Dependencies are inferred from the claim text.