Device for the variable control of the valves of internal combustion engines, more particularly for the throttle-free load control of 4-stroke engines

Apparatus for variable control of valves in an internal combustion engine having a crankshaft, said apparatus comprising

• first and second camshafts having fixed axes and acting on a rocker lever when in turn acts on a spring loaded valve,
• gear means for phase-shifting said second camshaft relative to said first camshaft, said gear means comprising a driving wheel driving said first camshaft and driven by said crankshaft, a first intermediate wheel driven by said driving wheel, a second intermediate wheel driven by said first intermediate wheel, and a driven wheel driving said second camshaft and driven by said second intermediate wheel, said first and second intermediate wheels having moveable axes, whereby moving said axes of said intermediate wheels phase-shifts said second camshaft relative to said first camshaft, and
• drag means comprising a pair of engaged wheels having different operative diameters mounted on respective first and second camshafts, and friction means effective between one of said pair of wheels and one of said camshafts, thereby generating a drag force which is superposed on the force transmitted to the second camshaft by the driven wheel.