A caster 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 include 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 pounds (45 kg) or less to 100,000 pounds (45 t). Wheel materials include cast iron, polyurethane, forged steel, plastic, rubber, stainless steel, aluminum, and more.

Types of Casters

Casters comprise two major categories: Swivel Caster Wheels and Rigid Caster Wheels.

Swivel Caster

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:
Locking casters,Kingpin-less casters,Hollow Kingpin casters,Plate casters,Stem casters

Rigid Caster

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.
Locking casters,Kingpin-less casters,Hollow Kingpin casters,Plate casters,Stem casters

Caster Design

Mount,Swivel head,Yoke,Spring mechanism,Wheel,Wheel bearings,Axle bolt and nut,Break.

Applications

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:

Load capacity (the total load applied on the casters)
The number of casters to be used on the equipment (usually four or six casters)
Floor type (concrete, steel, linoleum, carpet, etc.)
Floor condition (are there cracks, bumps, unlevel floors?)
Environment (is the equipment operating in high temperatures, wet or humid conditions, etc.)
Floor cleanliness (are the floors clean or contain debris such as metal chips, grease, gravel, etc.)
Many casters are specifically designed for each of the following applications.

Industrial and automotive,Heavy industrial,High temperature,Medical and so on