US Patent 7318399 Variable valve mechanism

A valve train comprises a poppet valve 18 actuated by two rotatable cams 30, 32 which can preferably be phase shifted relative to one another. A first rocker 39 is supported on a fixed rocker 40 shaft by way of an eccentric sleeve 42 that is rotatable relative to the rocker shaft 40. A second rocker 37 directly supported on the rocker shaft 40 acts to rotate the eccentric sleeve 42 about the rocker shaft 40. In this way, the first rocker 39, which is operated by a first cam 30 and acts on the poppet valve 18 has its axis of rotation displaced cyclically towards and away from the valve 18 by the action of the second cam 32 and the second rocker 37.