Working depth adjustment from the cab

A coupling rod between the depth control elements provides uniform adjustment at both the front and rear of the machine. The working depth can be adjusted infinitely-variably from the tractor cab, to permit individual reaction to the changing conditions within a field. An easy-to-read scale helps the orientation of the driver. As an alternative, the working depth can also be mechanically adjusted. A spindle is provided on each of the support wheels for this purpose.