Patent ID: 6868742
Filing Date: 2005-03-22
Classification: B25B

Abstract:
1. A method for determining a torque magnitude transferred to a threaded fastener at each one of a series of torque impulses delivered to the fastener by a torque impulse tool which includes a torque delivering rotation motor with a rotor, an output shaft connectable to the fastener, and an impulse unit intermittently coupling said motor to said output shaft, wherein said impulse unit comprises an inertia drive member connected to said motor rotor, said method comprising: determining a retardation magnitude of said inertia drive member during each impulse generating phase, calculating a magnitude of dynamic torque delivered to the fastener by said inertia drive member during each impulse generating phase as a function of said determined retardation magnitude and a total inertia moment of said inertia drive member and rotating parts of the impulse tool which form a rigid unit with said inertia drive member, and calculating a magnitude of installed torque in the threaded fastener as a sum of torque delivered by said motor and the dynamic torque delivered by the total inertia moment of said inertia drive member and the rotating parts of the impulse tool which form a rigid unit with said inertia drive member.