From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Article from 'The Autocar' detailing the invention of a springless resilient wheel, intended to make pneumatic tyres unnecessary.
| Identifier | ExFiles\Box 4\4\ 04-page21 | |
| Date | 19th July 1912 | |
| The Autocar. A Springless Resilient Wheel. July 19th, 1912 A Further Attempt to Render the Pneumatic Tyre Unnecessary. A FORM of resilient wheel has been invented by Mr. W. S. Boult, 32, North Side, Wimbledon Common, London, S.W., which depends for its resiliency, not upon any form of elastic material, springs, etc., but upon the torque of the drive. The wheel consists of a tyre carrying rim from which is suspended by means of a number of links the internal hub portion secured to or running on the axle. The principle is best explained by the aid of a model, therefore we reproduce herewith two photographs of a very rough cardboard model. Fig. 1 shows the position of the wheel members when the car is running on a smooth road; and fig. 2 indicates what happens when the outer rim and tyre encounter an obstruction. A is the outer rim and B the inner wheel, these being connected together by six links J.{Mr Johnson W.M.} C represents the propeller-shaft casing or radius rods, and D the axle. E is a driving drum (representing the worm wheel or crown bevel) round which an elastic cord F is wound. The outer end of the elastic cord F is attached to the front part of the member C, so that driving torque is applied to the wheel, tending to make it run forward as indicated by the arrow. This tendency to run forward is neutralised by the elastic G, which represents the opposing resultant of drag and weight. In fig. 1, which represents the conditions when running on a smooth road, it will be noticed that the links J have inclined considerably backwards, the inner wheel being consequently slightly raised. When the car is stationary and the drive disengaged the links are, of course, vertical, and it is only the torque slightly overcoming the weight which causes the backward inclination. In fig. 2 an obstruction H having been placed in front of the wheel, the inclination of the links is somewhat on the other side of the vertical—the inner wheel being lower and farther forward in relation to the outer wheel than before. In the model, of course, this relative movement of the wheel members is brought about by pushing the rim back with the obstruction, but in the case of a running car, the obstruction would delay the outer rim, giving it time to mount easily over the obstruction, while the inner wheel with its load would, it is claimed, be neither delayed nor lifted to the same extent, but relieved in this way of a considerable amount of the shock, in this manner performing the function of a pneumatic tyre. After passing over the obstruction the outer rim would run forward and again resume the position shown in fig. 1. The inventor also claims that if the obstruction were very large and the car were going fast the loaded inner wheel would swing first down, and then high up in front and pull the outer rim up over the obstruction. An important consideration in regard to these wheels is that their resilience does not vary with the load carried, as increased load means correspondingly increased tractive effort, so that the normal angle of the cranks remains constant. It must be mentioned that the model is purely diagrammatic, for it will doubtless be noticed at once that the links of a car wheel on this system would have to be situated between the two portions of the wheel; it would be impossible for the links of the model to swing round their centres. The inventor has, however, drawn up designs to scale showing how the system can be applied to car wheels. Fig. 2.—Showing the action of Boult's wheel when meeting a road obstruction or inequality. Fig. 1.—Cardboard model showing the principle of Boult's resilient wheel. The relative positions of the components being the same as under normal conditions of drive. Key: A, outer wheel rim carrying tyre. B, inner wheel suspended by driving axle C, propeller-shaft casing D, axle case E, drum representing driving drum gear member F, maybe cord representing driving shaft G, elastic cord offering resistance to forward motion H (see fig. 2), road obstruction J, links between inner and outer wheel members. | ||