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