Colloquially known as furniture wheels, furniture casters are wheel assemblies that are attached to the bottoms of furniture legs to provide furniture mobility and shock absorption. Their main purpose is to allow furniture to move across floors with minimal friction and scratching.
Furniture casters are typically used on beds, chairs and tables in homes, offices, schools, hospitals, banquet halls, restaurants, retail stores, truck garages and industrial manufacturing plants and warehouses. However, being able to roll tables, chairs and equipment platforms around smoothly is also important in the manufacturing industry because of the frequency with which equipment, workstations and chairs are moved around. Casters are also very important in hospitals, where computer stations, beds, IV racks and other equipment are constantly in transit. Furniture casters are primarily constructed of wheels, caster frames and legs. The wheels are positioned between the legs of the caster frame, which can be mounted to objects by an axle or bolt. There are two main types of caster frames: swivel frames, which allow full 360º movement; and rigid frames, which allow only back and forth movement. When the wheel is installed into the caster frame, two legs are attached to either side of the wheel and the wheel is held in place between these two legs by an axle or bolt. Examples of industry-specific furniture casters include medical and hospital furniture casters, which are medium-duty with soft rubber or polyamide wheels; and office and household chairs, which are made from lower-duty thermoplastic materials, although bed casters typically have strong metal housings.
The majority of furniture casters are made from materials that are specific to the surface they will be rolling on and the load they are carrying. The most common materials for furniture casters are rubber, which absorbs shock well and is noiseless, thermoplastic, which is ideal for clean environments; and molded polyurethane, which performs well in high-moisture applications. Common surfaces that furniture caster wheels come into contact with are carpet, hardwood and plastic. An alternative to furniture casters are furniture glides, which are wheel-less furniture leg attachments that allow furniture to sit or be moved across the floor with minimal friction and scratching. Office tables and household furniture, which remain stationary and do not need casters, usually use furniture glides instead of casters.