Abstract: A load responsive torque sensing unit adapted to drive the rotor of an axial flow combine and including a variable pitch V-belt input sheave, and an output shaft concentric therewith, the latter having means for connecting it drivingly to the combine rotor. The input sheave consists of a pair of sheave sections, one of which is axially fixed on the output shaft in direct driving relationship, and the other of which is axially slidable, but freely rotatable, relative to the output shaft toward and away from the fixed section for V-belt reception therebetween.

Abstract: A dual speed gear case mechanism adapted to drive the rotor of an axial flow combine and which receives its power from the combine engine. The mechanism includes a housing which is tiltably mounted on the chassis of the combine and has a rearwardly projecting input shaft which carries a variable diameter torque sensing V-belt sheave and a forwardly projecting output shaft connected in driving relationship to the combine rotor, the two shafts being offset from each other. Speed-change gearing within the housing is controlled by a shift fork having external operating connections. The housing tilts about the axis of the output shaft so that the input shaft may be adjusted toward and away from its associated drive sheave for V-belt tensioning purposes. Gauge mechanism is provided for facilitating a determination of the correct inclination of the gear case housing to attain proper V-belt tension.