Variable gear ratio drive mechanism for switch rails has rack with curved set of teeth engaging circular pinion on eccentric shaft to give continuously changing ratio as pinion rotates

摘要

A circular pinion (1) is mounted on an eccentric shaft and can rotate through a given angle (Phi). The teeth on the pinion engages with matching teeth on a longitudinally-movable (S) rack (2). The shape of the rack and the eccentricity of the pinion may be chosen to give the desires variation in gear ratio as the motion takes place.