Hand truck World

The castors wheel assembly for chairs and the like is disclosed in which the wheel axle and hub are permitted a limited vertical stroke in a slot, a vertically arranged spring being active against the peripheral surface of the axle so that, when the chair is unloaded, the springs of the wheels urge the latter down so that the hubs may engage a friction surface. When the user seats on the chair, the springs are compressed and the rotation of the wheels is unhindered. The total force of the springs in a chair shall overcome the chair’s own weight.

The castors wheel assembly, for chairs, said castor wheel assembly being characterized in that it comprises a body having a horizontally extending slot, said slot having a verticalextent, a pivot axle mounted within said slot for limited vertical movement, a pair of wheel-halves rotatably mounted on opposite end portions of said pivot axle, said body having at opposite ends of said slot seats each having tapered confronting walls,each of said wheel-halves having a hub positioned generally within one of said seats, a spring normally urging said pivot axle so as to bring said hubs of the wheel-halves into wedging frictional contact with said tapered seat walls, said spring being ofa strength to support its proportional share of the weight of an associated chair and being compressible under the load of a person in the chair to release said hub from said seats, said body having means mounting said body for rotation about a verticalaxis which is offset from the axis of said pivot axle.

The castors wheel assembly, characterized in that said axle has a portion received within said slot of a prismatic cross section to prevent rotation of said pivot axle relative to said body.

The castors wheel assembly, characterized in that said movable axle carries a radial pin received within said spring and extending into a bore of said body which receives said spring.

The castors wheel assembly, characterized in that each wheel hub carries a braking disc cooperating with said tapered seat walls.

The castors wheel assembly, characterized in that said tapered seat walls have head projections which axially retain said braking discs and prevent said wheel-halves from movement off of said pivot axle.

The castors wheel assembly, characterized in that said head projections have a resilient yieldability so as to permit the forcible insertion of said braking discs.

It is known to apply to the legs of chairs or armchairs castors-wheels, that is wheel to be mounted rotatably about a vertical axle which is skew relative to the axle of rotation proper of the wheel.

An inherent advantage of such wheels is that they are very easily slid on a floor but this feature can become a trouble when the chair is unloaded as the exceedingly high mobility of the chair may be an inconvenience for the user.

The object of this invention is to provide the castors wheel having a differential sliding capability, that is to say, a chair which becomes braked when unloaded, the ease of assembly of such a wheel being compatible with a mass production of thewheels in question.

According to the invention, the castors wheel assembly is composed by a body portion having a vertical pin about which the assembly can be rotated for orienting a wheel, the body having a horizontally extending vertical slot which is skew relatingto the pin axis and is adapted to receive a pivot axle movable in the vertical plane of the slot, the pivot axle carrying two wheel-halves each having a hub, each hub being housed, in its turn, within a tapered seating walls, a spring urging the pivotaxle in the slot to move the wheel-halves to positions wherein their hub engage the tapered seating walls.