Variable ratio transmission mechanism

A continuously variable transmission mechanism including a roller assembly comprising first and second rollers separately mounted in spaced relation for rotation about a first axis, a disc assembly comprising a disc carrier, first and second discs mounted on the disc carrier in spaced relation to each other for rotation about second axes transverse to the first axis and so that the peripheries of the rollers engage inwardly facing surfaces of the discs with each second axis located between the rollers, means for urging the discs towards the first axis into frictional driving engagement with the roller peripheries, ratio varying means for causing relative movement between the roller assembly and the disc assembly in a direction parallel to the first axis to vary the ratio of the transmission and a three element planetary gear set disposed physically between the first and second rollers and radially inwardly of the discs and having a first element rotatable with the first roller and second element rotatable with the second roller, with one of the first roller and the third element of the planetary gear set being a drive input to the mechanism and the other one thereof being a drive output from the mechanism, the mechanism defining a first fixed ratio power transmission path through said first roller and said first and third elements of the planetary gear set and a second variable ratio power transmission path through said first roller, said discs, said second roller and said second and third elements of the planetary gear set.