Abstract: A variable ratio drive assembly (10) including: a planetary gear device (13) having an input shaft (15), an output shaft (17), with the shafts having a common rotational axis (21), an input gear (16) attached to the input shaft, an output gear (18) attached to the output shaft, a carriage (20) mounted for rotation about said axis, at least one planetary gear (19) meshed with the input gear and output gear, the planetary gear being rotatably mounted in the carriage, a ring gear (23) fixed to the carriage so as to be rotated about said axis, a pump gear (24) meshingly engaged with the ring gear, a pump device (51) drivingly connected to the pump gear and restriction means to control the flow so that said pump device (51) applies a torque to said pump gear to control rotation of said ring gear and therefore rotation of said output shaft.

Abstract: A variable ratio drive assembly (10) including: a planetary gear device (13) having an input shaft (15), an output shaft (17), with the shafts having a common rotational axis (21), an input gear (16) attached to the input shaft, an output gear (18) attached to the output shaft, a carriage (20) mounted for rotation about said axis, at least one planetary gear (19) meshed with the input gear and output gear, the planetary gear being rotatably mounted in the carriage, a ring gear (23) fixed to the carriage so as to be rotated about said axis, a pump gear (24) meshingly engaged with the ring gear, a pump device (51) drivingly connected to the pump gear and restriction means to control the flow so that said pump device (51) applies a torque to said pump gear to control rotation of said ring gear and therefore rotation of said output shaft.