Abstract: A chopper drum assembly for a forage harvester including a chopper drum housing, a shear bar, a shear bar holder and a wear plate assembly. The chopper drum housing includes a first part and a wear plate assembly support surface. The shear bar holder is pivotally connected at a first end to the first part of the chopper drum housing and fixedly connected to the shear bar at a second end. A first end of the wear plate assembly is pivotally connected to the second end of the shear bar holder adjacent the shear bar, and a second end of the wear plate assembly is supported by the wear plate assembly support surface wherein, the wear plate support surface is arranged to be inclined to the horizontal.

Abstract: An adjustment apparatus for a forage harvester having a shear bar adjustably mounted on a housing. A chopper drum is supported from the housing and mounted for rotation about an axis and further provided with a plurality of circumferentially spaced knife supports to which at least one chopper knife can be adjustably secured. In use the chopper knives cooperate with the shear bar to chop incoming crop. The adjustment apparatus includes a lateral element, at least one location element and at least one radially inwardly directed guide surface. The adjustment apparatus also includes at least one shear bar alignment surface on one or more of the location elements.

Abstract: An adjustment apparatus for a forage harvester having a shear bar adjustably mounted on a housing. A chopper drum is supported from the housing and mounted for rotation about an axis and further provided with a plurality of circumferentially spaced knife supports to which at least one chopper knife can be adjustably secured. In use the chopper knives cooperate with the shear bar to chop incoming crop. The adjustment apparatus includes a lateral element, at least one location element and at least one radially inwardly directed guide surface, each radially inwardly directed guide surface describing a desired outer path of an unworn chopper knife. Each guide surface is adjustably located with respect to the lateral element.