Rack and Pinion Principle

The rack was originally a vertically mounted technical device with teeth, usually made of metal, to hang items in different heights. So seen in the kitchen, where the temperature in pots over open fires was regulated by changes in altitude on the rack.
As part of the progressive industrialization racks were used as machine elements. They are generally used to implement a rotary motion into linear motion or vice versa.

With rack actuators, the rack is a straight machine element with a number of uprisings, the teeth, in which a gearwheel interacts. This is how the tilting of a Bessemer converter is done by the help of a rack rotary actuator. The piston Hz (i.e. feed or procedure) of a rack rotary actuator is calculated according to the mean circumference of the ring gear of the drive gear and its speed n to Hz = π × d × n.

With the rack and pinion rotary actuators, the rotational axis of the gear is orthogonal to the displacement direction of the toothed rack.

Examples of movement transformations:

• Generating a rotational movement by displacing the rack to a hydraulic cylinder
• Generating a rectilinear motion by an electric motor