Abstract: A wheel lock assembly for reversibly rotatably mounting a wheel assembly which comprises an inner race and an outer race and bearings disposed therebetween on a trolley which includes a central bore having a central axis and having a substantially annular recess eccentric relative to the central bore. The wheel lock assembly includes an axle member, the axle member including a cylindrical body portion having a longitudinal axis and an enlarged substantially annular head portion eccentric relative to the longitudinal axis. The wheel lock assembly further includes a cap member and locking screw for fastening the cap member to an end of the body portion of the axle member to draw the cap member into frictional engagement with the inner face and to draw the head portion of the axle member into mating engagement with the recess of the trolley arm.

Abstract: A link pin for connecting a pair of side links to a center link disposed therebetween including rectangular head portions at each end thereof for retaining the pin within the side and center links and a shaft portion disposed between the head portions. The shaft portion includes a pair of end portions and a central portion therebetween and a central axis extending therethrough and first and second offset axes which are parallel to the central axis and disposed on each side thereof. The shaft portion further includes a central protrusion extending from the central portion and radially outwardly from the first offset axis and having an outer arcuate surface defining an arc circumscribed about the first offset axis and a lateral protrusion extending from each of the end portions and radially outwardly from the second offset axis in a direction opposite to the central protrusion, each of the lateral protrusions having an outer surface defining an arc circumscribed about the second offset axis.