Continuously variable transmission employing cable wound around variable diameter drums

Abstract

A continuously variable transmission system for coupling between a rotating drive shaft and an output shaft employs a first drum rotated by the drive shaft and a second drum connected to the output shaft. At least one, and typically both, of the drums have a region of adjustable effective diameter. A closed cable encircling the first and the second drums is wrapped around each of the first and the second drums a plurality of times so as to provide effective tractional locking even at low clamping forces. In preferred embodiments, a mechanism is provided for preventing creep of the cable along the drum. The mechanism typically includes a number of elements each having a helical groove and deployed such that the cable engages a part of the groove, and a mechanism for rotating the elements so as to change the portion of the groove with which the cable engages.

Dependencies are inferred from the claim text.