A
pinion gear transfers a rotatory motion to linear motion. Various size
of pinion gears are available for different applications. It is also
known as rack and pinion gear. Apart from mining purpose, it is widely
used in automotive industry in steering system and different machines. In steering; the rack and pinion gears are connected to the steering wheel through a shaft. The shaft makes the pinion turn when the steering wheel starts rotating. The rotating pinion glides the rack back and forth. The rack is connected to the tyre and the force makes the tyre rotate. This is how a pinion gear works in automotive steering which are used in cars. Whereas; the machines with movable table like milling and grinders, the pinion is affixed to a handle and the rack are connected to the underside of the movable table. Here the rack and the pinion move in linear motion moving the table back and forth in linear motion. It is applicable in grinders and milling machines.
Also the pinion gears are used in meat processing machines. Same like grinder, the pinion is attached on a handle in meat processing machine. But, the rack is affix to a plunger. The rack pressurizes the plunger into the meat holding section. Then the rack force pushes the meat from the spigot. There is a possibility that in future, pinion gears can be seen using in mini-machines and robots.