Abstract: A system for the lateral guidance of agricultural machines, especially harvesting machines to be guided along a line determined by a crop row or a stand of crop along a previously cut swath, has a deflectible sensor for feeling the position of the crop along the guide line and means for automatically steering the vehicle to maintain the latter along a predetermined path established by this line. The improvement of the invention comprises a deflector fixed rearwardly of the sensor to prevent excessive displacement thereof by individual stalks which may be out-of-place and thereby preclude an excessive response of the automatic steering system because of occasional out-of-place stalks.

Abstract: A row-crop harvester adapted to travel along the ground in a transport direction is provided with four crop sensors. One crop sensor is provided to one side and in front of the harvester and normally feels the edge of the crop in front of the harvester and generates an output that controls an automatic steering system which guides the harvester along this edge. Another sensor is provided at the back of the harvester on the other side from the front sensor and serves to feel the edge of the swath just cut. Another sensor in front of the cutter on the harvester detects a gap in the crop and serves to switch the automatic steering system over from the front sensor to the back sensor in case a gap appears in the crop so that the harvester will not swing back and forth to follow minor crop gaps. In addition another sensor is provided on the front of the harvester so that when it arrives at the end of the field the harvester is automatically stopped and can only be moved by manual takeover of the steering.

Abstract: A standing-crop harvester has a chassis adapted to be displaced along the ground in a transport direction and carrying a pair of guide wheels which are normally controlled from a steering wheel. A sensor carried on an arm in front of the machine detects the edge of a swath in a standing crop and generates an output which varies the impedance of one element of a bridge circuit. Another element of this bridge circuit has its impedance varied in accordance with inclination of the harvester on the ground, another element is varied in accordance with the speed of the harvester on the ground, and a fourth element is varied in accordance with the position of the wheels of the harvester relative to the direction of travel.