Flutter-resistant caster

Claim 1

A flutter-resistant caster comprising: (a) mounting means for attaching said caster to an object to be castered; (b) wheel-supporting means pivotally supported on said mounting plate; (c) wheel means rotatably supported on said wheel-supporting means; and (d) bearing means interposed between said mounting means and said wheel-supporting means, said bearing means including a plurality of solid hard rolling elements adapted to roll between a pair of races mounted for limited movement toward and away from each other between a first position where said races are spaced from one another by a distance substantially greater than the diameter of said hard rolling elements, and a second position where said races are sufficiently close to each other so that at least some of said hard rolling elements are rollingly engaged by both of said races; (e) said bearing means further including, between at least some of said hard rolling elements, a plurality of solid resilient rolling elements of similar shape but greater diameter, said resilient rolling elements being arranged to bias said races into said first position; (f) the compressibility and diameter of said resilient elements being such that under no-load conditions, they impose a sufficient pre-load upon said bearing means to impede fluttering of said caster, and that under load conditions, the load is borne essentially by said hard rolling elements without substantial interference by said resilient elements.