Continuously variable transmission capable of torque control

A continuously-variable-ratio transmission ("CVT") of a band-and-sheave type including control mechanism (17) operable (via 18) by a driver or other operator, a ratio-varying component ("variator") comprising at least one band (1) in driving contact with two pulley units (2, 6) presenting parallel but separated axes of rotation but sharing a substantially common radial plane, in which each pulley unit comprises shaft mechanism (5, 9) and two sheaves (3,4;

• 7,8) mounted thereon, axial separation of the sheaves being variable whereby to alter a radius of contact between the band and an associated pulley unit and so alter a transmitted ratio, in which there is a torque-sensitive connection (21, 22) between at least one of the pulley units and its shaft mechanism capable of generating an axial unit/shaft mechanism force that is a function of a magnitude and direction of a torque a pulley unit is transmitting, and in which loading mechanism (30, 15, 25, 36, 39;
• 31, 16, 26, 37, 39) operate on the pulley units to urge their sheaves together with a loading force characterised in that the torque sensitive connection comprises a power transmitting connection and the input of power to the variator by way of a shaft mechanism on either of the two axes has the effect, by way of the torque-sensitive connection, of tending to cause the axial separation of the sheaves of a unit on that shaft mechanism to increase relative to that of the sheaves of a corresponding unit on the other shaft mechanism.