Vertically adjustable caster

A heavy duty vertically adjustable spring biased caster comprising, in combination, a caster frame having an upper region and a lower region, caster mounting structure affixed to said frame upper region for attaching said frame to the member being supported by the caster, said frame lower region including spaced vertically disposed side plates each having outer and inner sides, a horizontally disposed pivot shaft extending between and through said side plates, pivot shaft adjustment means mounted on said plates' outer sides supporting said pivot shaft for selected vertical adjustment on said side plates, a caster wheel support pivotally mounted on said pivot shaft, a caster wheel rotatably mounted on said support having an axis substantially parallel to said pivot shaft and radially spaced therefrom, a spring cradle mounted on said pivot shaft, torque restraint means interposed between said spring cradle and said caster frame preventing rotation of said cradle on said shaft and permitting vertical adjustment of said cradle with said pivot shaft, and spring means interposed between said caster wheel support and said spring cradle biasing said wheel support about said shaft in a direction to engage said caster wheel with a supporting surface, vertical adjustment of said pivot shaft simultaneously vertically adjusting said caster wheel support, caster wheel, spring cradle and spring means.