A SUGGESTION TO TRACTOR DESIGNERS.
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RECENTLY I inspected a farm tractor on which the spuds were attached to the wheel rims, each by two bolts. The intention, I gathered, was that, when it was necessary to run the machine on a hard road, the spuds could be taken off. What degree of removability they would be likely to possess after a winter's work on a farm it is difficult to say, but it oecarred to me that it would probably be nil. That is, for all practical purposes, the spuds might have been made solid with.the wheel rims, as the bolts would probably be rusted ,into position and require to be' chiselledoff the rims 'before the tractor 'could be used on the roads.
Spuds that are to be effective on soft ground are obviously not fitted for road traction, and it is necessary either to remove them or to fit the wheels with rubber pads or something of the kind when' on the road.
In this connection, therefore, the two photographs which are published herewith may !be of interest to designers. Thep illustrate the method by' which this difficulty was surmounted on certain German gun-tractors used in the war. In this case the spuds are formed on the end of a series of arms disposed tangentially around, and pivoted to, a geared sleeve, which is capable of rotation relative to the wheel hub. A square key, projecting from the hub, enables the sleeve to be rotated, when it can he locked in position. When the tractor is used op a. 'hard road, the spud arms are in the position
• shown in the photograph, and the spuds do not protrude outside the wheel rim. On soft ground, rotation of the, sleeve brings the arms into a radial position, and the spuds protrude through the rim. This type of design appears to have distinct possibilities from the farm tractor point of view. I am not aware' whether it is patented or not, but doubtless some modification will suggest itself to designers, by which any such difficulty, should it exist, could be overcome.