Patent ID: 7390068

Claim:
An apparatus comprising: a base; a wheel by which the base is configured to be wheeled across a floor, the wheel including a tread and a hub, the hub having an inner surface surrounding an axis and defining a bore, an outer surface surrounding the inner surface, and a slot extending radially outward from the bore to the outer surface; a shaft that is centered on the axis and coupled to the base and configured to be received in the bore and has a groove; and a clip configured to be attached to the hub in an installed position in which the clip extends from within the groove outward through the slot to secure the hub to the shaft, the installed position being axially between the base and the tread; wherein the clip is configured to be pulled by a hook in a radially outward direction to withdraw the clip from the groove to release the hub from the shaft; and the clip can also be pushed in a direction opposite said radially outward direction, to withdraw the clip from the groove to release the hub from the shaft.