Variable speed reversible drive for a harvesting apparatus

Abstract

An agricultural crop harvester's feeding and gathering units are driven by a power source on the harvester through a sheave assembly journaled on a countershaft mounted towards the rear of the feeding unit. Power is thence transmitted by a variable ratio V-belt drive to a speed reducing and direction reversing planetary gear unit mounted forwardly on the feeding unit and finally to the gathering and feeding mechanisms by drives of conventional design. In the variable ratio V-belt drive, the effective diameter of a split sheave output portion of the countershaft sheave assembly is selectively adjusted hydraulically while, in inverse response, the effective diameter of a spring loaded variable driven split sheave, integral with the planetary gear unit, adjusts automatically. In addition, the driven sheave is provided with a coaxial cam arrangement responsive to changes in torque transmitted so that its effective diameter also adjusts automatically to provide appropriate belt tension. Interposing a speed reducing planetary gear unit in the drive system following the V-belt drive makes possible the use of comparatively higher belt speeds and smaller sheave diameters and facilitates provision of a selectively reversible drive to the gathering and feeding units. The reversed speed of rotation of the output of the planetary unit is substantially lower than its forward speed.