20120329601 | MULTIPLE-RATIO INDIVIDUAL-ACTIVATION TRANSMISSION DEVICE - The invention concerns a multiple ratio transmission device with permanent meshing, in particular for making a gearbox capable of providing gear shifts without interrupting the power transmission, for example an automatic control or sequential control gearbox. Said device comprises three coaxial planetary trains using selective coupling means so that each provides local direct drive or at least one transmission ratio. According to the invention, said device comprises two coaxial planetary trains (TP | 12-27-2012 |