A series of gear systems is disclosed, each of which comprises least one double-shaft, reversible planetary stage including a combination of an open positive gear system having lantern-gear teeth and an output system. “z1” represents the lantern-gear arrangement, and a number of teeth z2 is assigned...http://www.google.fr/patents/US7351177?utm_source=gb-gplus-shareBrevet US7351177 - Series of gearboxes
