the oldham coupling permits torque to be transmitted from the large planet gear 13 a to the small planet gear 13 b while allowing the axis of small planet gear to be offset from the axis of the large planet gear 13 a such that the small drive planet gear 13 b is free to float in the annular space between the ring gear 12 and the idler sun gear 11 optional bearings 20 may be used to support the small drive planet gears 13 b the bearings 20 provides a predetermined supporting stiffness in relation to the stiffness of idler planet gear support bearings 17 and 18 bearings 20 permits the small planet gears 13 b to float under a load and thus to distribute the load in a predetermined proportion between the small planet gears 13 b and the idler planet gears 14 a a further design variation is shown in fig7 where a drive planet gear assembly 13 g with a gear coupling is used to transmit torque from the larger planet gears 13 a supported on a double row roller bearing 16 dr to the small planet 13 b while allowing the small planet gear 13 b to float with respect to the large planet gear 13 a other design variations are possible without deviating from the sprit of current invention the embodiment and design variations disclosed herein should be considered as ways for explaining or implementing current invention not as ways to limit the scope of current invention other usage of current invention is also possible for example the input shaft and output shaft to the epicyclic gear train a can be reversed with proper design.