| 摘要 |
<p>A method and a device for determining the torque magnitude transferred to a threaded fastener (25) at each one of a series of torque impulses delivered to the fastener (25), including application of repeated torque impulses on the fastener (25) by a power tool having a motor (20) with a rotor (21) and a pulse unit (23) intermittently coupling the pulse unit (23) to an output shaft (24). The pulse unit (23) comprises an inertia drive member (27) which is accelerated by the motor (20) and arranged to transfer its kinetic energy to the output shaft (24) at each torque impulse, and a rotation detecting device (35, 38) is provided to indicate the instantaneous rotation movement of the inertia drive member (27). At each impulse generation, the intertia drive member (27) is retarded, and the retardation magnitude as a function of time is calculated, wherein the product of the retardation magnitude and the total inertia moment of the drive member (27) and other rotating parts of the tool forming a rigid unit with the inertia drive member (27) reflects the torque magnitude transferred to the fastener (25) at each impulse.</p> |
