C&e Fein Gmbh

Michael Kaufmann

Bernd Mayer

Ulf Rinckleb

A power screwdriver is disclosed, having a drive for driving a tool spindle having a controller for controlling the drive, having a monitoring device for monitoring the rotation speed or the torque, and having a monitoring device for monitoring a switch-off criterion, which monitoring device is coupled to the controller, in order to switch off the drive when the switch-off criterion is reached, with the controller being programmed such that (a) the drive is first of all accelerated until the rotation speed has reached a specific first rotation speed; (b) if the rotation speed then falls by at least a specific amount within a specific time increment, or the torque rises by at least a specific amount within a specific time increment, the drive is braked until the rotation speed has reached a specific second rotation speed, which is lower than the first rotation speed; (c) the drive is then regulated at the second rotation speed for a specific time; and (d) after step (c), the drive is accelerated again at most until the rotation speed reaches the first rotation speed.

Power screwdriver

The invention relates to a method for decelerating a drive movement of a power tool and to a power tool suitable for carrying out the method, having a drive driven by a motor, an energy supply device for the provision of electrical energy, a controller having a motor controller for activating the motor and an operating-state recognition module which is to detect at least one operating-state variable and, as a function of this, to output a brake signal, the controller being designed to initiate, as a function of the brake signal, a braking procedure in which brake cycles are provided which have a first time segment, in which the motor is short-circuited, and a second time segment in which current is fed to the motor opposite to its original direction of rotation.

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Ellwangen, Germany

Michael Kaufmann