A mechanism for varying the lift and duration of lift of the valves (1) of an internal combustion engine comprises a primary hydraulic cam follower (4) actuated by a primary cam (5), a secondary hydraulic cam follower (8) actuated by a secondary cam (7), a housing (18) for the secondary cam follower...http://www.google.fr/patents/US4502425?utm_source=gb-gplus-shareBrevet US4502425 - Variable lift cam follower
