This invention relates to improved casters and particularly to casters of a type having a capacity for resisting or absorbing heavy shock forces, such as may occur if a unit supported by the caster is suddenly dropped or a sudden vertical shock force is otherwise applied to it.
There are on the market casters which are intended to be shock absorbing in use, and which to attain that purpose include a first body structure connectable to a unit to be supported and a second body structure carrying a floor engaging wheel and which is connected pivotally to the first structure for deflection relative thereto upon imposition of a load on the caster. Such pivotal movement is usually resisted by one or more coil springs acting against the wheel carrying structure in a manner urging the wheel downwardly against the floor. Unfortunately, such devices do not produce as effective a shock absorbing action as would be desired since the springs in order to absorb high load forces without bottoming out under heavy load conditions must be too stiff to attain any substantial cushioning effect under light loads.
U.S. Pat. Nos. 1,745,992, 3,566,433 and 4,346,498 show devices of the above discussed general type in which elastomeric cushions have been utilized in lieu of coil springs as the shock absorbing elements.