Gears are commonly used to transmit rotational motion between machinery shafts. When gears of different types and sizes are combined, they can change the rate of rotation, the direction of the axis of rotation, and change rotary motion to linear motion.1 a toothed wheel that engages with another toothed wheel or with a rack in order to change the speed or direction of transmitted motion. 2 a mechanism for transmitting motion by gears, esp. for a specific purpose. Rack and pinion gear system is used to transmit rotary motion into linear motion. The rack is a portion of a gear having an infinite pitch diameter and the line of action is tangent to the pinion. It is helical gear box used as pinion driver Gears are mechanisms that mesh together via teeth and are used to transmit rotary motion from one shaft to another. Gears are defined by two important items: radius and number of teeth. They are typically mounted, or connected to other parts, via a shaft or base A pair of gears are compounded if they have a common axis and are integral, such as gear A, B, C, D and E.
