A gardening appliance has a traction drive system with a clutch, an electric motor drive system and a user-triggerable signalling device. The clutch is designed to, as a result of forward rotation, automatically engage for forward drive of the gardening appliance and, as a result of backward rotation, automatically disengage for freewheeling of the gardening appliance. The electric motor drive system is designed to effect the forward rotation and the backward rotation of the clutch. A method of operating the appliance includes: a) in a user-triggered manner by way of a change in a signal state of the signalling device, operating the electric motor drive system in a running-down and/or braking operating mode in order to lower a motor rotational speed of the forward-rotating electric motor drive system; b) acquiring whether a back electromotive force caused by the electric motor drive system or a variable based on the back electromotive force satisfies a standstill criterion, wherein the standstill criterion is characteristic of an attainment of a standstill state of the electric motor drive system; and c) when the standstill criterion is satisfied, operating the electric motor drive system in a backward-rotation operating mode to effect the backward rotation of the electric motor drive system for disengaging the clutch for freewheeling of the gardening appliance.

A clutch controller provides protective disengagement of a clutch between an engine and driven machinery to prevent engine failure due to rapid onset overload. Sensor signals of measured parameters are used by the controller to determine potential engine failure. Multiple, successive sensor signals and elapsed times are assessed during which the current sensor signal value and the scaled rate of change in signal values is compared against a predefined amount. The clutch controller sends a clutch disengagement signal if a calculation result is indicative of imminent failure.

A clutch controller provides protective disengagement of a clutch between an engine and driven machinery to prevent engine failure due to rapid onset overload. Sensor signals of measured parameters are used by the controller to determine potential engine failure. Multiple, successive sensor signals and elapsed times are assessed during which the current sensor signal value and the scaled rate of change in signal values is compared against a predefined amount. The clutch controller sends a clutch disengagement signal if a calculation result is indicative of imminent failure.

A method for operating a clutch in a power tool having an electric motor having an open-loop and closed-loop control device for closed-loop and open-loop control of motor power of the tool, and having a sensor, wherein the tool is operable in a first or second operating mode; in the first mode, the clutch is actuated after a predetermined time if a predetermined rotational speed threshold is undershot, and in the second mode, the clutch is actuated if a first predetermined motor current threshold value is exceeded. The method comprises setting the second mode; measuring the current of the motor; and reducing the motor rotational speed from a first rotational speed value to a second rotational speed value if a second predetermined current threshold value is exceeded, wherein a torque that can be generated by the tool is increased from a first torque value to a second torque value.

A gardening appliance has a traction drive system with a clutch, an electric motor drive system and a user-triggerable signalling device. The electric motor drive system effects forward rotation and backward rotation of the clutch. An operating method includes: a) in a user-triggered manner, operating the electric motor drive system in a running-down and/or braking operating mode to lower a motor rotational speed of the forward-rotating electric motor drive system; b) acquiring whether a back electromotive force caused by the electric motor drive system satisfies a standstill criterion, wherein the standstill criterion is characteristic of an attainment of a standstill state of the electric motor drive system; and c) when the standstill criterion is satisfied, operating the electric motor drive system in a backward-rotation operating mode to effect the backward rotation of the electric motor drive system for disengaging the clutch for freewheeling operation.