Patent ID: 8322946

Claim:
A material-leveling system comprising a material-leveling assembly including a mobile-support frame and a material-leveling implement coupled to the mobile-support frame to move with the mobile-support frame relative to ground, and an automatic-leveling system including means for controlling movement of the material-leveling implement relative to a reference plane established by a grade laser so that a final-grade level of material is established in response to the material-leveling assembly moving through a work area, wherein the automatic-leveling system includes an implement-positioning system arranged to interconnect the material-leveling implement and the mobile-support frame to cause the material-leveling implement to move relative to the mobile-support frame, a sensor system coupled to the material-leveling implement to move therewith and configured to sense the grade laser, and a control system interconnecting the sensor system and the implement-positioning system to cause position signals received from the sensor system to be converted into movement commands that cause the material-leveling implement to move so that the final grade level is established in the work area, wherein the sensor system includes a first vertical-position receiver unit coupled to the material-leveling implement and a second vertical-position receiver unit coupled to the material-leveling implement in spaced-apart relation to the first vertical-position receiver unit and the first and second vertical-position receiver units are arranged to extend in an upward direction away from the material-leveling implement, wherein the sensor system further includes a rotational-position unit coupled to the implement-positioning system to move therewith and spaced-apart from the first and second vertical-position receivers units to cause a rotational position of the material-leveling implement to be sensed by the sensor system.