Separating unit for combine harvesters

Abstract

A combine harvester comprising at least one generally cylindrical crop handling unit having tandem threshing and separating sections through which material is advanced along a generally helical path. A conveyor is provided for receiving crop material from a forwardly positioned crop header and delivering it axially into the cylindrical unit. During operation, grain is separated from the crop material and discharged through concaves and grates in the threshing and separating sections, respectively, onto a grain pan which in turn deposits it on cleaning sieves located rearwardly of the grain pan. The clean grain is elevated to a storage tank mounted on the combine while the residue is conveyed rearwardly and expelled onto the field. The grate in the separating section is cylindrical in configuration and comprises a plurality of generally transverse members retained by spaced longitudinal rub bars defining a configuration of apertures permitting discharge of grain over most or all of the circumferential surface of the cylindrical unit. One or more of the transverse members have at least one slightly askew section to assist advancement of crop material along its helical path in the separating section of the combine. A portion of the separation grate extends into the threshing section.