For educational use only. All rights reserved by the contributor(s) and publisher(s).
Gear, endless screw, worm drive
This gear pair model was created by the Illinois Gear & Machine Co. Chicago. Cornell University acquired a set of 15 models around 1950. A similar set can be found at Ohio State University. The so-called "endless screw" is a very old mechanism and can be found in machine drawings of Renaissance artist-engineers such as Francesco di Giorgio Martini and Leonardo da Vinci. The worm drive converts high speed motion about the horizontal axis [as shown in the model] and generates slower rotary motion about a horizontal axis perpendicular to the drive axis. The straight or right-angle worm drive is generally not back drive-able; i.e. one can only move the pair through the helical screw. However, the helical, worm gear pair can be driven from either the high speed helical worm or though the large slow speed gear with helical teeth. [See the Cornell Reuleaux-Voigt model C-9]