Abstract: An improved concave for use on a combine has a plurality of spaced-apart bars mounted parallel to the axis of rotation of the combine cylinder and at an angle with respect to a radial line passing from the center of the cylinder through each of the bars. The angle of inclination of the bars increases progressively from the intake end to the discharge end of the concave. The passageway between the concave and the cylinder also becomes progressively smaller from the intake to the discharge end of the concave. The angle of inclination of the bars aids the passage of grain between the bars and reduces resistence of the bars to the passage of grain therebetween.

Abstract: A combine includes a longitudinally extending auger mounted in a tubular casing and provided with spiral flighting for conveying cut crop material rearwardly between the exterior surface of the auger and the interior surface of the tubular casing. A longiutidnally extending threshing rotor is mounted on the rearward end of the auger for rotation therewith. A longitudinally extending concave embraces the rotor and is spaced from the rotor to define a threshing space therebetween. The concave includes a grate at its lower end, and an impeller is positioned below the grate for propelling grain and chaff downwardly from said grate toward the sieves and chaffing device below. The chaffing device includes a fan having two outlets for blowing the chaff away from the grain both above and below the sieves. A plurality of spring fingers are located below the impeller for engaging the grain.

Abstract: A combine is described including a longitudinally extending auger which is mounted in a tubular casing. The auger is provided with spiral flighting for conveying cut crop material rearwardly between the exterior surface of the auger and the interior surface of the tubular casing. A longitudinally extending threshing cylinder is mounted on the rearward end of the auger for rotation therewith. The cylinder has a flared configuration with its rearward end having a larger diameter than its forward end. A longitudinally extending concave embraces the cylinder and is longitudinally adjustably movably mounted with respect to the cylinder. The concave also has a flared configuration so that its rearward end has a larger diameter than its forward end and is spaced from the cylinder to define a threshing space therebetween. The forward end of the concave is in communication with the rearward end of the auger so that cut crop material will be delivered to the forward portion of the threshing space.