Automatic steering device for row crop harvesters

Claim 1

IN A ROW CROP HARVESTING APPARATUS WHICH INCLUDES A TRACTOR, A HARVESTER REARWARDLY OF THE TRACTOR, A TONGUE UNIT CONNECTING THE TRACTOR AND HARVESTER, SAID TONGUE UNIT INCLUDING A REAR MAIN PORTION RIGID WITH THE HARVESTER AND A FORWARD PORTION PIVOTALLY CONNECTED TO THE REAR PORTION FOR RELATIVE ROTATION ABOUT A VERTICAL AXIS, AND A FLUID PRESSURE RAM CONNECTED IN ARTICULATING RELATION TO THE TONGUE PORTIONS ON ONE SIDE THEREOF; A CROP ROW SENSING DEVICE MOUNTED ON THE MAIN TONGUE PROTION AND COMPRISING A PAIR OF TRANSVERSELY SPACED DEPENDING SENSING FINGERS ADAPTED AT THEIR LOWER ENDS FOR ENGAGEMENT WITH A CROP ROW, MEANS MOUNTING THE FINGERS FOR INDEPENDENT MOVEMENT IN A VERTICAL PLANE, MEANS ACTING ON THE FINGERS YIELDABLY URGING THE SAME DOWNWARDLY, AND MEANS CONTROLLED BY THE VERTICAL MOVEMENT OF ONE FINGER RELATIVE TO THE OTHER FINGER TO FEED FLUID UNDER PRESSURE TO ONE END OR THE OTHER OF THE RAM TO EXTEND OR CONTRACT THE SAME.