Abstract: A dual follower variable valve timing mechanism for varying the timing of the intake and exhaust valves of an internal combustion engine. Adjacent sets of angularly offset cams are provided on a rotatable camshaft for actuating each valve of the engine, one cam of the set providing a short duration timing and the other cam of the set providing a long duration timing. A first follower for each set of cams has leading and trailing portions having control surfaces which conjointly engage the respective cams. A second, crescent-shaped follower is pivotally mounted in one end of the rocker arm that actuates the valve and has control surfaces which engage the first follower. Links connect the first follower with a crank which is rotatable in opposite directions by a control mechanism responsive to different operating parameters of the engine.In another embodiment, the first follower includes spaced pair of leading rollers and a central, trailing roller which engage the cams.

Abstract: A mechanism for varying the timing of the valves of an internal combustion engine wherein an elongated finger follower for each of the intake and/or each of the exhaust valves of the engine is disposed between and movable while engaged with the cams for the respective valves and linkage means that extends between the valves and the finger followers. The proximal ends of the followers are pivotally connected to the swingable ends of a plurality of cranks, the opposite ends of the cranks being connected to a control shaft that is mounted for limited rotational movement about an axis adjacent and parallel to the axis of rotation of the engine camshaft. Each finger follower has a convex surface engageable with the actuating linkage for its associated valve and a concave control surface engageable with the cam associated with a particular valve.

Abstract: Mechanism for varying the timing of the valves of an internal combustion engine to obtain optimum efficiency and performance of the engine throughout a substantial portion of its operating speed range, wherein cam means for at least each intake valve is mounted on a rotatable cam shaft of the engine. Each cam means includes at least one and preferably a pair of axially spaced first cam members contoured to provide a first timing for their associated valves such as to provide optimum performance throughout one operating speed range of the engine and a second cam member of smaller size than and positioned between the first cam members and contoured to provide optimum performance throughout another operating speed range. Timing of the valves is normally controlled by the first cam members acting through linkage connected to the valves, and a plurality of elongated finger followers are provided for coaction with the second cam members to render them effective to control the timing of the valves.