Rack and pinions are used for lifting mechanisms (vertical movement), horizontal motion, positioning mechanisms, stoppers and also to permit the synchronous rotation of several shafts in general industrial machinery. However, also, they are used in steering systems to change the direction of vehicles. The characteristics of rack and pinion systems in steering are as follows: simple structure, high rigidity, small and Spur Gear Rack lightweight, and exceptional responsiveness. With this mechanism, the pinion, mounted to the steering shaft, is certainly meshed with a steering rack to transmit rotary motion laterlly (transforming it to linear movement) to ensure that you can control the wheel. In addition, rack and pinions are utilized for several other purposes, such as playthings and lateral slide gates.
As a mechanical component to transfer rotary into linear movement, gear racks are often in comparison to ball screws. There are benefits and drawbacks for using racks instead of ball screws. The advantages of a equipment rack are its mechanical simplicity, huge load carrying capacity, and no limit to the distance, etc. One disadvantage though is the backlash. The advantages of a ball screw are the high precision and lower backlash while its shortcomings include the limit in length due to deflection.
There are applications where in fact the gear rack is stationary, while the pinion traverses and others where the pinion rotates upon a fixed axis while the gear rack moves. The previous is used broadly in conveying systems as the latter can be used in extrusion systems and lifting/lowering applications.
To provide many variations of rack and pinion, KHK has many types of gear racks in stock. If the application requires a long length requiring multiple gear racks in series, we have racks with the tooth forms properly configured at the ends. These are described as “equipment racks with machined ends”. When a gear rack is produced, the tooth cutting process and heat treatment process can cause it to try & walk out true. We are 
able to control this with unique presses & remedial processes.