Abstract: A hydraulic reel drive wherein the reel motor is driven by a hydraulic pump, which is adjustable in a continuous manner and operates therewith in a closed oil circulating system. The advantage of this arrangement is that the reel always rotates uniformly independently of the instantaneous load thereon. Another advantage thereof is that by using a hydraulic pump, which is adjustable in a continuous manner, only that amount of oil is ever circulated as is required to drive the reel at a predetermined rotational speed.

Abstract: A control unit for an agricultural harvesting machine is arranged so that the width of a passage or opening between two machine elements can be precisely adjusted as simply as possible. Adjustable stops are in the form of plungers are displaceably guided in cylinders. Each cylinder is connected to a multi-chamber pump which contains a displaceable stepped piston. Individual chambers of the multi-chamber pump and the steps of the piston are mutually matched so that the same quantity of hydraulic fluid is squeezed out from the two chambers of the multi-chamber pump and the plungers move in and out in synchronism. The control unit is particularly suitable for use in foragers, combines other agricultural harvesting machines.