Patent ID: 8047741

Claim:
A milling machine for milling a ground surface, comprising: a chassis having a direction of travel; a running gear supporting the chassis and including front and rear track-laying units; a rotatable milling drum supported from the chassis between the front and rear track-laying units, the drum having a working width for milling a strip from the ground surface, the strip having two substantially vertical milled edges; a steering system operable to steer at least one of the track-laying units; a mechanical sensing member pivotable about a vertical axis and operable to engage one of the previously milled edges of a previously milled strip; a sensor associated with the sensing member and operable to detect an angular position of the sensing member about the vertical axis; a controller operably associated with the sensor and the steering system, the controller operable to steer the machine so that the machine follows a path defined by the previously milled edge engaged by the pivotable sensing member; a left-hand edge guard and a right-hand edge guard extending longitudinally adjacent two ends of the milling drum; a second sensing member, the first and second sensing members being connected to the left and right edge guards, respectively, the first and second sensing members being selectively activateable; and vertical adjustment mechanisms operably associated with the edge guards for adjusting vertical positions of the edge guards; wherein the controller is operable to detect one of the edge guards being in a higher position and the other of the edge guards being in a lower position, and the controller is operable to activate the pivotable sensing member associated with the edge guard in the lower position.