Patent ID: 8033751

Claim:
A control system for controlling movement of individual hydraulically moveable ends of a screed head carried by a boom of a machine so as to maintain a selected elevation position between each end of the screed head and a reference in a concrete paving application as the screed head is moved toward the machine, comprising: an elevation receiver, mounted on a first end of the screed head, providing a first signal indicating the position of the first end of the screed head in relation to the reference; an elevation receiver, mounted on a second end of the screed head, providing a second signal indicating the position of the second end of the screed head in relation to the reference; a first sensor, mounted on the screed head, for sensing the orientation of the screed head along its length from the first end to the second end and providing a third signal indicating such orientation; a second sensor for sensing rotational movement of the machine about a generally vertical axis which will induce an error in the third signal from the first sensor and providing a fourth signal indicating such rotational movement; and a control circuit, responsive to the elevation receivers and to the first and second sensors, for controlling the hydraulically moveable ends of the screed head using the first and second signals from the elevation receivers when the first and second signals are available, and for controlling the hydraulically moveable ends of the screed head using the third signal from the first sensor and the fourth signal from the second sensor, and one of the first and second signals from the elevation receivers when the other of the first and second signals is not available.