Forage harvester feed roll assembly designed for minimizing false

Abstract

A forage harvester includes a feed roll assembly for feeding a mat of crop across a fixed shear bar located adjacent a rotating cutterhead for cooperating with the cutterhead knives to cut the mat of crop into lengths. The feed roll assembly includes front and rear lower feed rolls mounted in opposition to and for being contra-rotated relative to front and rear upper feed rolls. The upper feed rolls are carried by a downwardly biased link assembly that is pivotally mounted for permitting the upper feed rolls to move up and down relative to the lower feed rolls in response to varying amounts of crop passing between the lower and upper pairs of feed rolls. A metal detector is mounted within the lower front feed roll and normally operates to a generate a balanced field which extends into the crop feed zone above the lower front feed roll. When a foreign object made of magnetic material passes into the balanced field, it causes the field to become unbalanced resulting in the sending out of a trip signal which actuates a system for immediately stopping the drive to the feed rolls so as to prevent the foreign object from being fed into the cutterhead. Hardened rings are located on the upper front feed roll support shaft and they serve as the inner race for cup bearings used to rotatably support the upper front feed roll on the support shaft.