ABSTRACT
A higher power, and a smaller size, is the main trend in the evolution of the power sources for the application in modern machinery. Three principal components are recognized in modern machinery. These are a source of power, and a working member, that are connected to each other by means of a transmission. Gears made of wood represent a perfect example of gears most extensively used in the past. Wooden gears were used in the design of windmills for pumping seawater, and for producing flour. In the pre-Eulerian period of gear art, numerous intuitive attempts were undertaken to come up with the most favorable geometry of a gear tooth flank. The condition of contact between the tooth flanks is the first fundamental condition to be met in gearings of all types in parallel-axes gearing, in intersected-axes, as well as in crossed-axes gearing.
