A Novel Form of Spring Suspension by
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Means of Pneumatic Tires.
An interesting attempt to reduce the cost of the wear and tear of pneumatic tires, whilst not impairing their resiliency, has been made by Mr. Frederick Hughes, of 1, Arthur Street East, London, E.C. A model of that gentleman's invention has been submitted to us for examination, and it is shown in two of the accompanying illustrations; we also reproduce a diagram which conveys our own suggestion for its adaptation to the back wheels of commercial vehicles. Mr. Hughes is a firm believer in the principle of pneumatic suspension for motor vehicles, but he realizes that the cost of upkeep of air-filled rubber tires for heavy commercial vehicles presents a formidable barrier against their use, and that there are also serious objections against the adoption of any system of pneumatic spring suspension in which pressure tanks, pistons, etc., form component parts.
In the device under notice, although pneumatic tires are employed, no part of their surface is at any time in contact with the road. The main axles are guided by horn plates which are secured to the chassis, and the road wheels which ride on these axles may be shod with steel tires, or, in order that the noise of their running may be minimized, treads made of wood or vulcanite may be fitted. Mr. Hughes proposes to mount the chassis on pneumatic-tired wheels of small diameter, with ordinary laminated springs interposed between their spindles and the frame, and then practically to carry the wheeled chassis over a pair of axles which are located on the chassis by means of the horn plates already mentioned. Small pneumatic-tired wheels are also mounted on the roadwheel hubs. The latter wheels are so disposed that they make rolling contact with the small spring-mounted pneumatic-tired wheels on the chassis. The inventor, by this arrangement. hopes to get the same effect, so far as easy riding is concerned, as would be obtained were the pneumatic tires actually rolling over the surface of the ground : the road shocks, it may be noted, are absorbed before they reach the bearing springs, and they are therefore not transmitted to the chassis. The drive is, of course, transmitted directly to the road wheels,
either through a live axle, or by means of side chains in the manner shown in the above diagram. While the vertical component of each road shock will be absorbed by the pneumatic tires, the horizontal component must be resisted by the horn-plate brackets.
It may be impracticable to adapt this system to existing vehicles, but the idea is certainly novel, and one that offers scope for investigation by enterprising manufacturers. In the accompanying diagram, we show what we consider to he a more-practicable method of applying the principle of pneumatic suspension—using air-filled tires, which are not in contact with the road—than that adopted by Mr. Hughes for his model. The diagram shows a detachable rim suitably registered and secured to the inner face of each road wheel, and, instead of fitting the spring-mounted wheels with pneumatic tires, as is suggested by the inventor, we would adopt plain steel rollers of small diameter. The large pneumatic tire would, of course, have to be of sufficient size and strength to carry the chassis and its imposed load. but, as its tread rolls over an even and polished surface—the peripheries of the rollers, it need not have the wearing surface and armouring of a tire of like size, such as is fitted to an ordinary motorcar wheel. Further, this pneumatic tire does not transmit any of the drive from the engine, and, consequently, a cheaper form could be produced of sufficient strength to carry the load, whilst, as the walls of the outer cover would not require to be so thick and unwieldy, the tire would be more resilient for a given size of inner tube than any ordinary form of pneumatic tire.