Transmissions of the toroidal-race rolling-traction type

A variator transmission of the toroidal-race rolling traction type comprising at least two input discs (1-4) and at least two output discs (11-13) arranged alternately in coaxial sequence, wherein all discs except the first (1) and last (4) in the sequence are formed with part-toroidal races (9, 10) on both faces of the disc thereby defining a sequence of at least four clearances where an input and output race confront each other across an imaginary torus, and

• a separate set of rollers (14-19) of adjustable orientation arranged to transmit traction across each successive clearance between the respective input and output races;
• means to exert a control force on each said roller;
• each said roller being free to adjust its said orientation to a valve at which the said control force is balanced by the resultant reaction force exerted upon the roller at its interface with the said input and output forces;
• and means (35-19) to transmit drive from the output discs to at least one rotatable output member.