harvested crop material is fed to the cylindrical cutter - head of a forage harvester by a feeding assembly consisting of opposed pairs of upper and lower feed rolls . the articulated upper roll assembly floats to accommodate variations in the flow of crop material . the downstream upper feed roll is carried on a pair of opposite radius arms which are rigidly coupled by a transverse leveler shaft , providing a stable frame and minimizing cocking or twisting of the roll . a second pair of feed roll arms is pivotally connected to the radius arms and extends forward to support the upstream feed roll which is journaled on a shaft rigidly connected between the feed roll arms . a stop and biasing arrangement provides that each upper roll may float independently , the articulation of the feed roll assembly being such that upward movement of either roll or the rolls together is subject to the restoring force of a tension spring . however , upward movement of the upstream roll in relation to the downstream roll is restricted by a stop which limits rotational movement between the feed roll arms and the radius arms supporting the rolls .