Abstract: The swivel caster includes a wheel, a yoke leg and a plastic top cap. The wheel is underneath and assembled with the yoke leg by a nut and axle which is through two axle holes of the yoke leg and the center of the wheel hub. There is an open hole in the yoke leg body so a metal shaft can bolt up inside and then be pressed into the inner hole of the plastic top cap. There is an insert molded into the yoke body hole and the upper part of the insert performs as a raceway. The king pin or metal shaft, extends through the insert and is then fixed with the plastic top cap. The raceway of the insert holds several small metal balls. The plastic top cap has a lip that forms a raceway for the small balls.

Abstract: A caster includes a yoke having a yoke leg with a yoke leg axle opening through the yoke leg. A wheel having a hub and a hub axle opening through the hub is attached to the yoke leg with an axle bolt. A thread guard is located between the hub and the yoke leg. The thread guard has a disk-shaped body with a thread guard axle opening through the body for receiving the axle bolt. The thread guard further includes an outer surface facing toward the yoke leg and an inner surface facing toward the hub, and the outer surface includes a raised ridge extending away from the body. The ridge substantially surrounds and conforms to the shape of the yoke leg. The ridge preferably extends from the body past the outer surface of the yoke leg.