BOLT-TIGHTENING METHOD USING AN IMPACT WRENCH

摘要

The present invention provides an impact wrench and a bolt-tightening method such that a spring force is applied, through the circumference of a spindle coupled with the output shaft of an electric motor, in the forward direction to a hammer which is capable of forward and rearward movement and rotational motion following the spindle. An impact sensor detects release of the hammer from the impact shaft and an angle sensor measures the angle of rotation of the impact shaft. This permits measurement of the torque of the impact shaft by measuring the amount by which the angle of rotation of the impact shaft advances each time the impact force is generated.