Patent ID: 7510472

Claim:
A crop residue system positioned downstream from a rotor of a combine, the rotor conveying a crop material supply path, the crop residue system comprising: a chopper assembly extending laterally across the material supply path, the chopper assembly having a rotary chopper element with a plurality of blades mounted thereon, the chopper assembly further includes a chopper grate assembly including a grate portion mounted generally parallel to the rotary chopper element across the material supply path to define a material flow path between said grate portion and the rotary chopper element, said grate portion including a plurality of spaced slots therealong, said slots extending generally transversely across the grate portion in general alignment with the direction of material flow along the material flow path; an active counter knife assembly having a shaft rotation axis therethrough, positioned generally beneath and parallel to said grate portion, the active counter knife assembly including a rotatable shaft having a plurality of knife elements mounted thereon at positions generally alignable with said slots of said grate portion, said rotatable shaft rotatably movable about its shaft rotation axis, said knife elements of said rotatable shaft and said slots of said grate portion coordinately sized to permit said knife elements to project and move through said slots as said rotatable shaft is caused to rotate about its shaft rotation axis; and a drive mechanism operatively connected to said rotatable shaft and operable to rotatably drive said rotatable shaft about its shaft rotation axis, such that at least one of the speed and direction of the rotatble shaft is varied.