Self propelled mower with safety device

Abstract

An autonomous self-propelled mowing vehicle includes a frame fitted with a drive mechanism, a mowing device for mowing plants, a bumper device, and a control unit. The bumper device includes a first and a second impact detector. The first impact detector is depressible up to a stop and is provided with a first switch which emits a first signal to the control unit at a first switching point, if the first impact detector is depressed beyond the switching point. The second impact detector is deformable and locally depressible, and is provided with a second switch which emits a second signal to the control unit if the second impact detector is depressed at least beyond a predetermined depression threshold. The control unit is configured to stop the drive mechanism upon receiving the second signal, and to regulate the drive mechanism in such a way that the speed of the mowing vehicle is reduced to a lower mowing speed upon receiving the first signal without receiving the second signal. This prevents plants to be mowed from pushing the bumper away across the bumper width beyond the switching point of the first impact detector, without losing its long depressibility, because the second impact detector, which itself has a much smaller depressibility, detects obstacles at the lower (mowing) speed by being depressed itself.