This invention relates generally to grain threshing apparatus and in particular to an apparatus for threshing grain wherein an impeller is rotatable within a concave or tubular screen. This application is a division of application Serial No. 560,552, now Patent No. 2,906,270. An object of this invention is to provide an improved apparatus for threshing grain.
Buchele, Wesley F., "Apparatus for threshing grain" (1963). Iowa State University Patents. 15.