Patent ID: 7017438

Claim:
A hydraulic gear selection drive means in combination with a cone gear selector comprising a hydraulic drive assembly having an input piston, an output piston and a hydraulic coupling between the input and output pistons, the output piston being adapted to move into a gear engagement position in response to movement of said input piston in order to engage a gear, the hydraulic coupling and input and output pistons being mounted co-axially with the gear being selected, the cone gear selector employing a female cone surface and a male cone body having a driven cone surface and a driving cone surface, the driven cone surface being located between the driving cone surface and the female cone surface, the male cone body being axially moveable by a male cone body drive means to cause said cone surfaces to engage, the male cone body drive means comprises said hydraulic drive assembly, said hydraulic drive assembly of said male cone body drive means includes a fixed annular cylinder assembly with thrust bearings coupling the output piston to the male cone body.