Patent ID: 7926584
Filing Date: 2011-04-19
Classification: B25D,H01F,H02K,H02P

Abstract:
1. A method of controlling a hand-held power tool including a striking piston ( 5 ) for applying blows to a working tool ( 7 ), a linear motor ( 2 ) for driving the striking piston ( 5 ) and including a rotor ( 3 ) displaceable axially along a percussion axis (A), and an air spring ( 4 ) located between the striking piston ( 5 ) and the rotor ( 3 ), the method comprising the steps of displacing the rotor ( 3 ), in a first operating state ( 17 a ) that corresponds to a stable percussion operation between a front, in an operational direction of the power tool, reversal point (W) located near the striking piston ( 5 ) and a rear reversal point (W) spaced from the front reversal point; displacing the rotor ( 3 ) toward the striking piston ( 5 ) in an operating state ( 17 b ) other than the first operating state ( 17 a ) and which includes a delay step ( 18 ) in which the rotor movement toward the striking piston ( 5 ) is delayed electromagnetically; and a calculating step ( 22 ) that precedes the delay step ( 18 ) and in which computing means ( 9 ) of the power tool calculates a delay time (tV) at which the delay step ( 18 ) is initiated from sensor-acquired data of a kinematic actual movement state (l(x(t), v(t), a(t)) of the rotor ( 3 ).