This valve has been designed for use with two cylinders in sequence for reversible plough to obtain the automatic alignment of load andits overturning. The rotation of the frame is upwards. Two different calibrated restrictors have been designed, depending on the diameter of the overturning cylinder, onto which the valves are fitted. This valve allows the plough to be stopped at 90° (dead head point). Operating instructions: first the alignment cylinder starts lining up the load. Once it reaches the end of stroke, the overturning cylinder starts the rotation. Upon the completion of this the alignment cylinder takes the plough back into its working position. It is possible to interrupt the overturning cycle at any point and retake the plough to the working position.