A Tractor Wheel with retractable spuds
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A FTER two years of practical development a new type Nvheel for agricultural tractors has gone into production in Germany, the maker being Atlas, G.m.b.H., Augsburg, X, Neuburger Str., 38, Germany. This interesting wheel resembles a hollow drum, and it contains a mechanism by means of which a set of spuds, movable radially in slots in the rim, can be pushed out to any degree or withdrawn so that the wheel can operate on the field and on the road. Its rim has, in all, 12 slots, arranged obliquely across the tread, and the spuds sliding in them are stout steel plates. By means of two connecting rods linked on the inner corners of these plates, each is connected to a common muff on the hub inside the wheel, and therefore concentric with the axle around which the wheel turns. When this muff is turned in one direction, the connecting rods all force out the spuds, whilst the reverse movement causes these to be drawn in.
The mechanism operating the movement of the spuds has to be stationary in relation to the revolving wheel. This problem has been solved in an ingenious and simple manner. Fitted on the side of the wheel turned towards the tractor is a brake drum with an internal ring of teeth. The drum turns constantly with the wheel until an external band brake is applied, which holds the drum while the wheel continues revolving. Meshing with the internal gear of the dram is a pinion, which extends inwardly beyond the drum teeth and there engages with a rack in loop form.
The pinion shaft being fixed on the side of the wheel,
this rack is forced to move and, being in the form mentioned, it will successively move backwards and forwards, because in one way the teeth along the inner top edge, and in the other way those along the inner bottom edge, mesh with the pinion. The loop rack is connected with the muff and, therefore, effects the necessary movement of the latter. The spuds are locked automatically in any position, the moment the brake is released, by pawls engaging with the internal gear on the brake drum and preventing its movement.
Both driving wheels of a tractor have naturally to be of this type, but only a simple brake mechanism is required to control the spuds on them. The plates can be moved only when the tractor is running. If the new wheel fulfils expectations it will do away with the irksome and timerobbing fitting or detaching of spuds or rings on agricultural tractors. Also the grippers are self-cleaning, which is an asset.