Motorized turning tool e.g. screw driver, has two coils, where electric signal present between two coils is measured, and control unit arranged to determine position of metal part according to physical characteristic of measured signal

摘要

The tool e.g. screw driver, has a moving metal part comprising a core and two coils that are connected electrically in series. A production unit is arranged to produce a control signal at extremities of a coil assembly to generate an electromagnetic flow so as to move the moving part from one position to another position. Electric signal present between the two coils is measured. A determination unit or a control unit (4) is arranged to determine a position of the metal part according to a physical characteristic of the measured signal.