Abstract: A forage harvester comprises a feeder for feeding harvested crop material to the processing mechanism along a crop feed path It is equipped with a foreign object detector for signaling the presence of foreign objects in said harvested crop. The detector comprises a sensor having a detection field extending into at least a portion of said path. The sensor is substantially symmetric with respect to a direction transverse to the crop feed path and the detector further comprises a restriction system distinct from said sensor, making said detection field asymmetric with respect to said transverse direction. As a result, the detector becomes less sensitive to noise caused by the other components of the harvester.

Abstract: A forage harvester is provided with a front unit, comprising a rotatable cutterhead to which crop material is fed by stationary lower feedrolls and movable upper feedrolls. The latter are journalled in a pair of bearing housings, connected to load arms, which are linked to crank arms pivotally attached to a feeder frame. Each load arm has a protruding member to which a spring is attached for compressing incoming crop material to an even mat. The springs also push the upper feedrolls rearwardly to compensate the reaction forces from the material flow and prevent excessive wear of the feedroll axles at their passage through the feeder frame.