GEARS

Spur gears• gear having involuted teeth either straight or helically cut on a cylindrical

surface. Two such gears are used to transmit power between parallel shafts

Worm gear

• 1.A gear consisting of a spirally threaded shaft and a wheel with marginal teeth that mesh into it.

• 2.The toothed wheel of this gear; a worm wheel.

Crown gear• a gear whose teeth project parallel to the axis and whose pitch surface is a

plane