Shortly after lifting the plough, the beam is swivelled in without causing any stress before the turnover process starts. The furrow width is not changed by swivelling in the beam. This prevents wear, especially on the plough body bearings, and also enables a higher ground clearance during turnover. Once the plough has been turned, the frame swivel cylinder automatically returns the beam to the working position. The swivel cylinder extends in accordance with the furrow width. In this respect, a push/pull cable relays the position of the furrow width to a valve, thereby restricting the cylinder travel.