| 摘要 |
A method and a device for determining the torque magnitude transferred to a threaded fastener at each one of a series of torque impulses delivered to the fastener, includes application of repeated torque impulses on the fastener by a power tool having a motor with a rotor and a pulse unit which intermittently couples the motor to an output shaft. The pulse unit includes an inertia drive member which is accelerated by the motor and transfers its kinetic energy to the output shaft at each torque impulse. A rotation detecting device indicates the instantaneous rotation movement of the inertia drive member. At each impulse generation, the inertia drive member is retarded, and the retardation magnitude as a function of time is calculated. The product of the retardation magnitude and the total inertia moment of the drive member and other rotating parts of the tool forming a rigid unit with the inertia drive member reflects the torque magnitude transferred to the fastener at each impulse. |
