Caster wheel

A caster (British spelling is castor) is a wheeled device typically mounted to a larger object that enables relatively easy rolling movement of the object. Casters are essentially special housings that includes a wheel, facilitating the installation of wheels on objects. Casters are found virtually everywhere, from office desk chairs to shipyards, from hospital beds to automotive factories. They range in size from the very small furniture casters to massive industrial casters, and individual load capacities span 100 lbs or less to 100,000 lbs (45000 kg). Wheel materials include cast iron, plastic, rubber, polyurethane, forged steel, stainless steel, aluminum, and more.

Casters comprise two major categories: a swivel caster pivots around a kingpin, so it rotates as well as rolls, while a rigid caster has its wheel mounted in a fixed frame, or rig, and only rolls.

This type of caster allows for movement in multiple directions. They can have one or two sets of raceways that allow the caster to swivel 360 degrees under a load. The different types of swivel casters include the following:

This style of caster only allows forward and backward movement. Rigid casters tend to be stronger than swivel casters. They are rated at the same capacity as the swivel casters for safety reasons. They can be a one piece construction or a two piece construction that is riveted or welded.

The key dimensions to consider when determining the proper type of caster and caster size for a particular type of equipment and application are its overall height, swivel radius, and swivel offset (see Caster Dimensions diagram). The key elements of a caster include the following:

Casters are available in a large selection of various rigs and yokes, wheel materials, swivel offsets, and wheel configurations. In many cases, it can become extremely difficult to choose the right caster for the application. In order to help the user to determine the right caster to use, it's important to take a couple of factors into consideration, which include:

Many casters are specifically designed for each of the following applications.

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