Abstract: A drive mechanism having a sprocket and a belt with inter-engaging lugs and receptacles on the belt and sprocket, respectively, wherein orthographic motion is obtained of the lugs into and out of the receptacles so as to provide for smooth, high efficiency transmission of drive forces by providing a fulcrum at inter-pitch spacing positions about which the belt bends along a radius centered at the fulcrum to bring the lugs directly into registry with the receptacles in the sprocket. The system provides virtual sprocket teeth, thereby effectively doubling or multiplying the number of teeth on the sprocket, compared to lugs on the belt so that a small, low-inertia, sprocket-belt drive system effectively provides the smoothness of transmission of a system with twice or greater the number of sprocket teeth than lugs, but without the cost of such additional teeth and lugs and without sacrificing belt life due to additional flexures of the belt.