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Wheels for Detachable Solid Tires.

27th April 1911, Page 7
27th April 1911
Page 7
Page 7, 27th April 1911 — Wheels for Detachable Solid Tires.
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Which of the following most accurately describes the problem?

Most commercial-vehicle users have experienced annoyance due to delays in the re-tiring of wheels, particularly if the tires fitted are of the band section, such as is now admittedly superior to the clinched pattern for heavy loads. It is not every wheelwright who possesses a hydraulic press of sufficient power to force on to the felloes a large band-section solid-rubber tire, and various methods have been devised Ii) obviate the necessity for the use of such a press. The Polilek Co. offers a Colonial type of tire in which the band is staked on to the felloes by means of wooden wedges. Another system which has been somewhat-extensively used is that of the Shrewsbury-Challiner Co., in which a steel cone is forced in, by means of bolts, between the tire and a cone-shaped rim which surrounds the felines.

Quite recently, an entirely-new method has been brought to our notice : it is the invention of Mr. E. W. Thomas, of 48, Chatsworth Road, Luton, and takes the form of a cast-steel wheel, as illustrated herewith. It will be noticed that, in this wheel, the rim is not continuous. In the illustration given there is one gap in the rim, hut, of Coil SC. there may be two, three or any number of gaps, according to the size of the wheel and the load intended to be carried. Each gap --or the one gap if only one be provided—is occunied by a wedgeshaped block. The ends of the rim, which butt against the side of this block, are provided with flanges, and these at e drilled to take bolts, by means of which the ends of the rim may be clamped against the wedge-shaped block. The object of the gap or gams in the wheel is to enable the ends of the rim to be drawn towards one another when the block is removed, and, thereby, the rim may be contracted and the diameter of the wheel appreciably diminished. When the ends are thus drawn together, and the wheel temporarily made smaller in diameter, a band-section tire may be slipped over the wheel rim. When the tire has been placed in position, the tension bolts may he removed, thus allowing the rim to resume its normal condition and diameter, so far as the rubber tire will permit. The spring in the wheel rim will then grip the band-section tire more or less firmly.

Further pressure may be applied by drawing in, sideways, the wedgeshaped block or blocks. The taper on these wedges is approximately one in 30, and the bolt. by which each wedge is drawn into position has cutupon it a 1A-in. standard Whitworth thread. The axial force which may be obtained on a 11-in. bolt by the application of the average pressure which a man is capable of exerting at the end of a standard single-ended spanner, for such a bolt, is about seven tons, and, as there is an additional mechanical advantage, due to the taper of the wedge, of 30 to one, there is available for the purpose of expanding the wheel within the tire, if we neglect friction, a force of Do tons on the ends of the rim, which pressure, it will be agreed, should be sufficient to expand the wheel and securely to retain the tire in position.

The rim of the steel wheel should be machined up, with the block or blocks in position, to the normal or expanded diameter, so that the wheel need only be distorted while a tire is being fitted or removed from the wheel. it is obvious that the true circular shape of the wheel iint cannot be altered without creating stress in the wheel spokes, and, in order to enable these spokes so to adapt themselves temporarily to the distortion caused by the contracting of the rim, they are made of curved shape, as shown in the transverse sectional view of the wheel.

One of our views has been reproduced from a photograph of a quarter-full-sized model that has been made for experimental purposes, and in this model it was found possible, by means of a t-in. Whitworth bolt, to distort the rim sufficiently to enable a tire to be mounted or dismounted.

We understand that the patentee desires to place the rights of his invention with a manufacturer who would be prepared to put it on the market on a commercial scale. If, as we anticipate, it should prove entirely satisfactory in use, it should be highly acceptable to commercial-vehicle users in the Colonies and abroad, as well as in many places in Great Britain and Ireland which are far remote from any tire maker's depot, or a powerful hydraulic press.

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People: E. W. Thomas

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