Patent ID: 6697570
Filing Date: 2004-02-24
Classification: B25D,H02H,H02P,Y10S

Abstract:
A process for a start-up safety routine of an electrical hand-tool that produces at least one direction of rotation and comprises an electrical motor and a safety device, wherein the safety device is actuated by a microcontroller upon exceeding a limit value (&agr;G) and interrupts the transmission of the torque between a tool and the electrical motor; the process comprising the steps of connecting the electrical motor to the current supply, for a short time period (T0), using one of a fixed impedance and a resistance determined by the microcontroller, wherein the impedance is zero and wherein the step of connecting includes the step of directly connecting the electrical motor to the power supply; measuring, via the microcontroller, the angle of rotation (&phgr;(t)) of the rotor using measurement means that determine one of the angle of rotation (&phgr;(t)) and the speed over the time period (T0); calculating, via the microprocessor, one of the angular acceleration of the rotor and a value dependent on the angular acceleration of the rotor based on the measured angle of rotation (&phgr;(t)) of the rotor and; ascertaining from one of the angular acceleration of the rotor and the value dependent on the angular acceleration of the rotor at least one of a limit value (&agr;G) and a shut-off point in time (tA) using a projection of a rotor start-up acceleration readable by the microcontroller.