Patent ID: 8636568

Claim:
A combine threshing system comprising: (i) a rotor comprising: an in-feed area at a front end of the rotor; and a rotor body configured to convey material along a helical path from the front end of the rotor body to a rear end of the rotor body, and (ii) a substantially cylindrical threshing chamber positioned circumferentially around and spaced apart from the rotor body, the threshing chamber comprising: a lower portion substantially concentric with the rotor body and having an inner surface positioned at a first distance from an outer surface of the rotor body; and an upper portion comprising: a first inner surface substantially concentric with the rotor body and positioned at the first distance from the outer surface of the rotor body; and a second inner surface substantially concentric with the rotor body, the second inner surface being discontinuous with the first inner surface and positioned at a second distance from the outer surface of the rotor body, the second distance being greater than the first distance, wherein the first inner surface of the upper portion of the threshing chamber and the inner surface of the lower portion of the threshing chamber occupies about 270 degrees of the circumferential perimeter of the rotor body or less than about 270 degrees of the circumferential perimeter of the rotor body at an edge of rotor body.