Toothed Gears

Toothed gears are used to transmit motion and power between shafts rotating in a specified velocity ratio. Although there are other, and often simpler, ways of doing this (such as belt drives and friction discs) few provide the positive drive without slip and permit such high torques to be transmitted as the toothed gear. Furthermore, gears adequately lubricated operate at remarkably high efficiencies, over a very wide speed range (limited only by imperfections arising during manufacture or assembly), and between shafts whose axes are parallel, intersecting or skew.