Reliance Precision Limited

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  • Racks and Pinions

Racks and Pinions

A rack and pinion system gives the ability to transfer rotary to linear motion, with all the accuracy expected of a geared system.

The racks are manufactured from ground, hardened stainless steel or ground stainless steel and available with a choice of accuracies, pitches, and lengths, plus the facility to provide modifications such as flats, journals or custom ends. Hobbed stainless steel and brass racks are also available.  The rack pinions are plain or anti-backlash, also with a choice of accuracies, pitches, bore sizes, alternative materials and coatings.

Ground racks can be used for both measurement and actuation. In general the smaller pitches (1 mm) suit measurement as the smaller pinion diameter gives higher linear resolutions. The larger pitches (2 mm and 2.5 mm) allow for a higher load capacity. For most applications the rack can be used for both the feedback and the actuation; however in very precise applications it is best to us a non-drive section of the rack for feedback, alternatively a separate rack can be used. Hobbed racks are more suited to light actuation applications where cost is a key consideration.

We offer three types of rack – rectangular racks, solid round racks and tubular racks.  Rectangular racks are used when the application requires the rack to be stationary and the rack pinion provides the element of motion. Our rectangular racks are used with a motor, slide and carriage for example in the printing industry for the actuation of paper cutting knives in a printing press. Round racks are a more flexible alternative, with regard to mounting, used for example in XY stages. The tubular racks allow for the passage of fluids, fibre-optics, gasses etc, making them ideal for medical and scientific applications, such as laboratory automation pick and place mechanisms.  

For a fully integrated solution the Racktuator™ is a combined rack and intelligent motor  actuation system. Bringing together Reliance’s racks and Cool Muscle servo system, the Racktuator™ provides a very high level of control and accuracy in a compact, space saving package.

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