Rack and pinion

The rack was originally a vertically mounted technical device with teeth, usually made of metal to hang objects in different heights. Thus, the temperature was regulated in pots over open fires due to altitude changes on the rack (boiler hooks), for example, in the kitchen.

As part of the ongoing industrialization racks were also used as machine elements. They serve as a rule for converting a rotary motion into rectilinear motion and vice versa.

Applications:

  • Mountain railway technology ( rack railway )
  • A method of machine parts with the aid of an electric motor
  • Weirs

Geometry of the rack

  • Geometries of toothed racks

Konchoidenverzahnung

Cycloidal

The geometry of the rack corresponds to the unwound geometry of a gear with involute, cycloid or Konchoidenverzahnung. The distance from one tooth to the next tooth is the division of a rack. Divided by the division results in the module of the rack.

The rack to a gear involute has straight flanks.

Applications

Rack and pinion drive

  • Operating principle of the rack drive

Animated rack and pinion drive

The rack and pinion the rack bar is a straight machine element with a number of elevations, the teeth in the gear engages. For example occurs tilting a Bessemer converter using a rack and pinion drive. The stroke (eg feed or path ) of a rack and pinion is calculated according to the mean circumference of the ring gear of the driving gear and its speed.

The rack drive gear wheel the axis of rotation is orthogonal to the displacement direction of the toothed rack.

Examples of motion transformations:

  • Generating a rotational movement by displacing the rack to a hydraulic cylinder
  • Produce a linear movement by an electric motor

Dental splint

However, the most well-known application, this system for rack railways, where the rack as a rack rail running in the rail bed between or is mounted adjacent the leading and supporting rails. In cog railways, a distinction different technical rail traction wheel systems such as:

  • Rack systems of rack railways

Double gearing system Abbot

Rack on sleepers

Ladder rack system Riggenbach

Tooth tip rod system Strub

Drawer drive

Less known, but probably much more widespread is the use of the rack and pinion drive as a drawer of CD players, DVD players, CD and DVD drives and other technical and electronic equipment. The laser unit is moved in some CD and DVD drives by means of a reduction gear and a rack.

Rack and pinion steering

Another large field of application is the use in steering systems. The rack and pinion steering is used in particular in the car to use. A distinction is made between racks with constant and variable ratio. The variable transmission is realized by a change in the toothing geometry on the rack stroke. Inventor of the principle of variable gearing is the Australian Dr. Arthur E. Bishop. In the 1940s, Bishop developed a steering system for the front wheel of an airplane (U.S. Patent 2,508,057 ) before in the 1950s, a steering gear with variable tooth pitch for use in an automobile steering gear followed. In 1958, the first patent was granted with respect to variable gearing and its principle of ratio change, in the form of the wave type rack with eccentric pinion (U.S. Patent 2,865,339 ). This is the first patent of variable tooth pitch for the automotive industry dar. 1973, the use of variable gearing using a helical pinion Bishop has been patented (U.S. Patent 3,753,378 ). In this form the principle of variable gearing is still used today. In 1978, Bishop Y- sectional shape of a rack patented (U.S. Patent 4,116,085 ). 1981 first time chose the Isuzu Piazza, a steering gear with variable tooth pitch to Bishop in conjunction with a helical pinion. The mass production took place at the company JKC from Japan, which followed a hot forging process used for this purpose by cold stamping. In 1982 the use of the variable gearing to Bishop in a steering gear in Holden JB. In subsequent years, Bishop developed process technologies for mass production of variable rack gear with higher accuracy than that of the hot forging with cold embossing. 1986 Bishop patented an apparatus for semi- hot forging of Y - shape rack with variable tooth pitch (U.S. Patent 4,571,982 ). 2001 Bishop was awarded the '' Australian Engineering Innovation Excellence Award '' for the Bishop forging technology for precision semi-hot forging. 2002 racks were first used with variable teeth in Formula 1. In 2003, Bishop PACE Award for apparatus for automatic precision semi-hot forging of variable rack and pinion gears. 2005 The company founder died and inventor Dr. Arthur E. Bishop. Even today, the company owns Bishop Steering Technology Limited many of the hundreds of patents that are registered under the name Bishop. 2010, the companies of the Bishop Steering Technology Group were purchased by the Georgsmarienhütte Group ( GMH group). Developed by Bishop semi-hot forging technology for Y- and D-form rack is still regarded as the leading technology for the mass production of car racks with variable tooth pitch.

Rack jacks

A further application of the rack, the rack winds.

Trammel hook Involute gear Conchoid (mathematics) Perimeter Orthogonality Railroad tie CD-ROM#CD-ROM drives
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