What is Caster?
Casters are small pivoted wheels. They are not equipped with cars or other means of transportation, but fastened to the ends of supporting legs of heavy things, such as furniture, pianos, beds in hospital and etc., to facilitate easy movement of these heavy objects.
Furniture casters were invented and patented by David A. Fisher, Jr., an African American inventor, on March 14, 1876 (U.S. patent # 174, 794). With the rapid development of modern industrial, casters are becoming diverse in functions, materials and appearances. For instances, we can see rubber casters, stainless steel casters, swivel casters, heavy duty casters, corner casters, wide rolling casters and so on in our lives.
Generally speaking, the coefficient of rolling friction is much more less than that of sliding friction. Therefore, under the same weight, the force of sliding friction to prevent move an item is much more than that of rolling friction. That is, it is much easier to “roll” an item than to “push” it. That is why wheels are used in all means of transportation on ground, so do casters for furniture and other heavy items.
With the help of casters, we only need less force to move heavier objects since casters can roll on the ground other than slide. At the same time, casters reduce the potential of injuries in work related movement.
The most common materials used for the construction of casters include metal, such as zinc and brass, and rubber. The architectures of casters are made of metal to provide enough support while the resilient material such as rubber is used for wheels of casters to guarantee the rolling capability. Although the functions of casters are same, different types of casters have different performance and the selection of casters should be determined by the circumference of applications.