US Patent 7699728 Variable speed transmission

A variable speed transmission of the continuously variable type. The transmission includes an input pulley having primary and secondary sheaves and an output pulley having primary and secondary sheaves. The primary and secondary sheaves of the input pulley are mounted on a first axle shaft carried by an actuator plate and the primary and secondary sheaves of the output pulley are carried on a second axle shaft carried by the actuator plate. The input shaft of the transmission carries pin mounted roller bearings which are received in skewed slots in an actuator sleeve so that the actuator sleeve is moved axially along the input shaft in response to variations in torque loading. The actuator plate is annular and includes a central circumferential groove receiving pin mounted roller bearings carried by the actuator sleeve so that the actuator plate, and the axle shafts carried thereby, undergoes the same axial movement as the actuator sleeve in response to variations in torque loading. One sheave of each pulley is fixedly mounted on the respective axle shaft and the other sheave is slidably and rotatably mounted on the shaft. The mounting of the pulleys on the respective axle shafts is such that axial movement of the actuator plate has the effect of moving the sheaves of one pulley apart and simultaneously moving the sheaves of the other pulley together whereby to cause the entrained drive belt to move radially outwardly relative to the sheaves of one pulley while moving radially inwardly with respect to the sheaves of the other pulley whereby to change the drive ratio of the transmission.