Casters are devices of fork assemblies and wheels, which are fixed to the base of the equipment for the purpose of easy mobility. The functions of casters are to swivel, roll, turn and move. Caster wheels operate by means of bearing above the wheels that give them a 360 degree rotational freedom. The accessories of castor wheels include swivel locks, swivel assembly seals, wheel bearing seals, wheel brakes and thread guards. Casters are attached to equipment by means of mounting plate or by inserting an expandable rubber stem or round or square solid stem into the tubing or by bolting octagonal shaped stem with cross drilled holes into the angle iron legs or by a threaded stem which goes into a tapped hole and which is locked in place with a lock nut. Factors to be taken account in casters are capacity, roll ability, flooring, and operating environment. Usually nylon, stainless steel, rubber, plastic and aluminum are used for manufacturing casters.
The types of casters are listed below:
Single wheel casters
Dual wheel casters
Ball wheel casters
Light duty casters
Heavy duty casters
Central lock caster wheels
Medical caster wheels
Hospital bed casters
Maneuverability and flexibility
Simplifies the job of house cleaning
Provides frontal support in wheel chair base
Improves space utilization
Casters are used in furniture, shopping carts, home appliances like refrigerators, office equipment, institutional equipment, and in medical equipment such as stretchers and beds. Heavy duty casters are employed in platform trucks, assemblies, and carts. Industrial caster wheels are employed in shipping and storage industries due to their low speed and manually manipulated applications. For outdoor or in gritty and irregular surfaces, pneumatic castors are used. For stability in pebbled areas, rubber castors are ideal.