Input: the green cone.
Output: the pink cone.
Three orange balls contact with both cones.
Each ball has its shaft that slides in radial slots of the yellow fixed disc and in oblique slots of the blue disc.
Turn the blue disc through a worm wheel drive to change angular position of the ball axis, hence distances from contact points (with the input and output cone) to the ball axis, for desired output velocity.
The yellow fixed ring is for positioning the balls.
The pressure at contact places is created by red springs.