Patent ID: 8434437

Claim:
A valve drive system comprising a support element and switchable cam follower that is linked on the support element in an articulated way, wherein the cam follower includes an outer lever having arms between which an inner lever runs, at least the outer lever is provided on a top side thereof with a contact surface for a lifting cam, the inner lever has, on a bottom side on a first end, a contact for a gas-exchange valve and at least on the other end includes two side walls that are spaced apart and in which opposing boreholes extend, the side walls are bridged by a single, tubular axle piece that sits in the boreholes and includes an opening in which two diametrically opposed coupling pistons run, the single, tubular axle piece extends between the side walls in a cross borehole in a head of the support element, the levers run on a common swivel pin in a region of the first end and on the other end, the arms of the outer lever have a catch surface for the coupling pistons, the coupling pistons are brought out from the opening into engagement with the catch surfaces section-wise in a coupled state, such that a large valve stroke is realized and a comparatively smaller valve stroke or a zero valve stroke is provided for decoupling, the outer lever is forced back by a restoring spring from a pivoted mode, and the arms of the outer lever extend in a direction toward the other end only up to the axle piece and grip over the axle piece like a roof with a half-shell-like or quarter-shell-like segment as a catch surface, such that, for the coupled case, the coupling pistons can be extended section-wise under the catch surface and an extension thereof is limited at an inner end of the segment.