Abstract: A caster includes a wheel body having a hub portion and an axle extending from the hub portion. Lock engaging members are disposed around the hub portion. An upright mounting frame includes a lower mounting portion journalled to the axle, and an upper mounting portion extending upwardly from the lower mounting portion. The upper mounting portion is spaced apart from the wheel body to define an upright passage therebetween. A support frame is movable relative to the mounting frame, and includes an upper force transmitting member to support a load. A confining member extends downward from the upper force transmitting member into the upright passage, and has an outer wall facing the wheel body. A spring member biases the upper force transmitting member to move upwardly and away from the mounting frame.