Variable diameter torque sensing drive

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. A compression spring yieldingly biases the shiftable section toward the fixed section, while a cam on the shiftable section cooperates with a pair of cam followers which rotate in unison with the fixed section and shaft in such a manner that an increase in the load on the output shaft will cause the cam to ride on the followers and force the slidable section toward the fixed section, thus increasing the side forces acting on the V-belt to prevent belt slippage, thereby tensioning the belt only insofar as is required to transmit the necessary torque for output shaft driving purposes. The unit is designed for cooperation with a special draw bolt arrangement which facilitates dismantling of the unit.