Patent ID: 7424919
Filing Date: 2008-09-16
Classification: B25B

Abstract:
1. A method for determining an angular displacement of an output shaft of an impulse nut runner at tightening of a screw joint to a desired final torque level, wherein the impulse nut runner includes an impulse unit with a motor driven inertia drive member delivering one torque impulse per full revolution relative to the output shaft, and an angle sensing device arranged to detect a rotational movement of the inertia drive member, said method comprising: defining a threshold torque level from which the rotational movement of the inertia drive member is to be detected, determining a total rotation angle of the inertia drive member accomplished by a total number of torque impulses counted from said threshold torque level, and calculating a total angular movement of the output shaft accomplished by the total number of torque impulses counted from said threshold torque level by reducing said determined total rotation angle of the inertia drive member counted from said threshold torque level by the total angular movement of said total number of full revolutions minus one full revolution.