Patent ID: 7702493

Claim:
A method for quality assurance of screw joint tightening of a screw joint to a needed pretension condition (F N ) by a torque delivering power tool, comprising: performing at least one simulation procedure of a screw joint tightening process via a specific algorithm aiming at said needed pretension condition (F N ) by using programmed data concerning screw joint geometry, expected frictional conditions, operational characteristics of the power tool, a chosen tightening strategy, and adaptable values of at least one tightening parameter, thereby arriving at a simulated pretension condition (F S ) acceptably close to said needed pretension condition (F N ), performing in practice a practical screw joint tightening process by controlling the power tool in accordance with said chosen tightening strategy and aiming at said needed pretension condition (F N ) by using said specific algorithm as well as programmed data concerning said screw joint geometry, said operational characteristics of the power tool, and tightening parameter values as derived from said simulation procedure, thereby arriving at a practically processed pretension condition (F P ), comparing said practically processed pretension condition (F P ) with said simulated pretension condition (F S ), and evaluating the outcome of said comparison for quality acceptance or refusal.