driving phonograph turntables. In automobiles Automobiles using this drive system included the Anglo-Dane, the Arista, the Armadale, the Astra, the Allvelo, the Bukh & Gry, the Cartercar, the Crown 12HP Model Two (1905-1906), the Davis Totem, the Kelsey, the Lambert, the LuLu, the Metz, the Ner-a Car, the Richardson and the Turicum. The Turicum's friction drive consisted of a flat steel disk coupled directly to the engine. This primary disk subsequently drove a smaller leather covered wheel oriented normal to its surface. Assuming a constant rotational velocity on the primary wheel, the angular velocity on the disk's surface will increase proportionally to the distance from the center of rotation. Therefore, positioning the smaller wheel at different points along the larger wheel's surface varies the gear ratio. Furthermore, since there are no limitations beyond the minimum and maximum positions, the gear ratios are infinitely adjustable. The Lambert's friction drive (illustrated) was similar but used an aluminium-faced driving disk and a fiber-faced driven wheel. In railway locomotives Plymouth Locomotive Works's first three models, the AL, BL and CL were equipped with a friction drive. Early models of the permanent way maintenance ganger's Wickham trolley used a vee-twin JAP engine. This drove through a large flat flywheel and a friction drive. Belt drives A belt drive is a form of friction drive but is usually categorized separately from the "disk and wheel" type of friction drive. See also References External links Animated image of a toroidal CVT on HowStuffWorks Automotive transmission technologies Continuously variable transmissions