Patent ID: 9101090
Filing Date: 2015-08-11
Classification: A01D,B62D

Abstract:
1. A direction control mechanism for a differential speed steered agricultural machine comprising: right and left drive motors; right and left hydraulic drive pumps connected in tandem to and driven by an engine, each drive pump having a displacement control mechanism including a pintel arm rotatable between first and second positions, rotation of which changes hydraulic fluid flow rate from respective drive pumps to control speed and direction of respective drive motors; a control input shaft connected to the left and right pintel arms, the shaft rotatable about its longitudinal axis and translatable along its longitudinal axis, rotation of the shaft causing simultaneous rotation of the pintel arms in opposite directions, translation of the shaft causing simultaneous rotation of the pintel arms in the same direction; a steering drive motor connected to the control input shaft to rotate the shaft thereby managing relative displacement of the right and left hydraulic pumps; a steering wheel connected to rotate a hydraulic steering valve to the right and left of a central position, the steering valve directing a volume of pressurized hydraulic fluid dependent upon the degree and direction of steering wheel rotation from the central position to the steering drive motor causing rotation of the control input shaft in proportion to the degree of rotation of the steering wheel; an automated steering control apparatus receiving signals from a vehicle guidance system indicative of the degree and magnitude of right and left direction inputs to steer the machine along a predetermined track, the automated steering control apparatus directing a volume of pressurized hydraulic fluid to the steering drive motor, the volume dependent upon the degree and magnitude of the direction change necessary to steer the machine by causing rotation of the control input shaft necessary to achieve the required direction and magnitude of the machine directional change; and a selector valve positionable between first and second positions, the first position enabling machine steering by the steering wheel, the second position enabling machine steering by the vehicle guidance system.