Patent ID: 8863355

Claim:
A caster wheel assembly comprising: a hub, said hub comprising a generally annular body centered about a central axis, said hub having an outer peripheral rim section and an inner bearing section, said hub further including an annular web section disposed between said rim section and said bearing section, said bearing section including an inner bearing seat defined by a counter-bore, said rim section including an annular outer rim surface, said rim surface including an annularly dished concave region disposed between a pair of cylindrical lips, a bearing, said bearing disposed inside said counter-bore of said hub, said bearing comprising a roller bearing having a plurality of roller elements trapped between inner and outer races, a bushing having a cylindrical outer surface disposed inside said inner race of said bearing, said bushing further including a flange configured to abut an axial face of said bearing inner race, a tread surrounding said rim surface, said tread fabricated from a resilient elastomeric material, said tread having a convex inner periphery conforming to said annularly dished concave region of said rim surface in a nested relationship, said tread further including a cylindrical pad on each side of said convex inner periphery, said cylindrical pads disposed in direct surface-to-surface contact with said cylindrical lips of said rim surface, said tread further including an outermost rolling surface, said outermost rolling surface being convexly rounded, and wherein said annularly dished concave region of said outer rim surface has a parabolic OD cross-section, wherein said parabolic OD cross-section is defined by the equation y=A*x 2 , where A is between 1.5 and 4.