US Patent 7849760 Speed changer with pre-determined gears, particularly for cycles

A speed changer is used to control derailleurs using cables from a single rotating handle, the deraileurs being connected respectively to an elastic return element. The speed changer includes at least two cable-maneuvering mechanisms. The mechanism for maneuvering the cable of the rear derailleur, which rotates integrally with the handle, can cause the rear cable to loosen or tighten when the handle is rotated in one direction. The speed changer is characterized in that the rotating assembly, formed by at least one mechanism for maneuvering the rear cable and the handle, can be connected to rotate intermittently with the mechanism for maneuvering the front cable of the front derailleur which, depending on the direction in which the handle is rotated, can cause the front cable of the front derailleur to tighten or loosen.