A planetary gear-set for continuously varying the output ratio between torque and rotational velocity, in which a central static sun-gear is considered as a reference to all other components. The structural aspects include a set of segments of a ring gear each such segment includes a linked couple of cogwheels. Another set of couples of linked cogwheels, is a sun-gear follower and the coupled member is output transfer cogwheel. A mechanism for changing the orientation of the output transfer cogwheel with respect to the sun-gear follower. A transient link connects between the above two separate systems of sets.