Controlling tightening force of bolt connection - by tightening, releasing, retightening using force computed from torque angle differential, achieved torque and bolt pitch

摘要

The method of controlling the tightening force of a belt connection involves tightening the bolt with a screwdriver (15) to a state below the final desired tightness, loosening it, computing the required force to achieve the desired state, and then tightening it. The computation takes into account measured values of the differential of the screwdriver torque versus angle in the second step and the final tightening torque during the third step as well as the bolt pitch. ADVANTAGE - Does not require absolute angle measurement and excludes angle measurement errors associated with reversing bolt rotation direction.