A NEW FORM OF TYRE CONSTRUCTION.
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A Résumé of Recently Published Patent
Specifications.
FINE OF the most interesting tyre Li patents of recent years is covered by specification No. 222,956, for which The Dunlop Rubber Co., Ltd., are responsible. It appears to foreshadow a new type of tyre, neither normal nor joiv-pressnre, but coming somewhere between the two. It would seem to have the advantages of both and the disad
vantages of neither. Its interest for motor users of all classes can hardly, therefore, be exaggerated.
The difference in principle between the normal and low-pressure types of tyre, and their comparative advantages and. disadvantages, are summed up in the preliminary paragraphs of this specification. It runs : "t has been customary, in some cases, to maintain relatively
high-fluid pressures in the tyre, and, in other cases, to increase the sectional dimensions and reduce the thickness of the casing. Such high-inflation pressures as are necessary to enable the tyres to support the loads they are called upon to carry with the smallest amount of deflection practicable, whilst they reduce the amount of flexing which takes place and thus prolong the life of the tyres, seriously reduce their cushioning proper ties. On thc other hand, tyres having increased sectional dimensions with thin casings, although they enable the use of reduced inflation pressures, and minimize the damaging effects of flexing, offer serious disadvantages in other respects." If the objects of the present invention be attained, then the damaging and de structive effects of flexing upon the cas ing will he greatly reduced, the carrying capacity maintained, and the cushioning value increased, without incurring the disadvantages which arise from the use of tyres of largely increased section, having specially thin walls.
To understand the main feature of this new tyre it is necessary, first of all, to become acquainted with some of the details of the construction of ordinary tyres. As a rule, a pneumatic tyre cover is built up as a casing of two or more plies of cotton cloth, cord fabric, or other textile material coated with thin layers of rubber to enable them to adhere to each other. To the outer surface of the casing so formed is affixed a suitable protecting enver of rubber having such additional thickness at its centre as may be desired, to form the tread or wearing portion. Covers built up in this manner are usually moulded to shape and vulcanized in moulds properly to secure the adhesion of all parts together.
In practice the life of a tyre so consiructed depends largely upon the ability of the textile fabric of which the casing is formed to resist the flexing to which it is 'subjected by constant bending of the tyre as each portion of its circumference successively comes under load and is released therefrom as the tyre revolves.
In this new tyre, instead of arranging the textile material as the inner layer of the tyre cover, as has hitherto been the practice, so that the inner layer lies concentric with and immediately sur rounds the air tube, it is now constructed with the textile component arranged within the rubber walls of the cover in P50 such a manner that it does not lie concentric with the inner tube. It is disposed eccentrically to the wall of the inflated tube in such a manner that the portion of the textile component lying under the tread of the, tyre forms the inner surface of the cover, whereas at the sides and base portions it lies near the outer surface of the cover and at some distance from the inner surface. ;
Such an arrangement provides a tyre cover having walls of approximately even thickness except a t the tread portion, where an ad-. sitional thickness of rubber may be added to provide for tread abrasion. The textile component passes gradually through the wall of the cover from the inside surface under the tread portion to a point near the outside surface at its edges or beads.
These new tyres will be, most probably, slightly larger in diameter than the normal or high-pressure tyres which they will be designed to replace. The effect of the re-arrangement of the textile lining, as described, will be to prevent the crushing of the timer plies on flexing. In this new design it will be the -inner
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rubber face of the walls of the cover which will sustain the crushing force due to the flexing. Several constructions, all of them embodying the principle which has just been described, are referred to in the specification. The drawing which we reproduce is typical.
Other Patents of Interest. AccoRDING to II. R. Ricardo, it is well known that as the mixture strength of the charge in an .internalcombustion engine is reduced; the -thermal efficiency is increased. In addition, the heat flow is reduced, and the general reliability and durability of the engine-more particularly as regards those parts which are directly affected by the heat, such as the exhaust valyes and the sparking pings, are improved. The difficulty is that it is not, in the usual type of engine, possible to use mixtures of the preferred low strength. In the engines which he describes in specifications Nos_ 222,971 and 222,972,, a method of surmounting this difficulty is patented. Mixtare of about the usual strength is introduced into the cylinders by orthodox . means, at the usual times, and in the usual place, namely, near the head of the cylinders. At the end of the suction stroke, there is a further induction of air or of air diluted by inert gas. The introduction of this second, and subsidiary charge, is effected in such a manner that stratification occurs, the rich mixture staying at the top of the cylinder near the ignition point, whilst the air, or dilute air, stays near the lower end. It is'claimed that the main charge is easily ignited, and that the consequent turbulence thoroughly mixes the two charges so that the expanding mixture has a comparatively low temperature and exhibits all the properties of a very weak mixture.
THE invention which is described in 'specification 'No. 222,955, by S. E. Alley, is mainly applicable to light locomotive construction, but may be used in connection with road vehicles. Its object is to promote the accessibility of the various components of a steam-engined. vehicle. The frame Overhangs both axles at front and rear. At one end the boiler is located, and at the other the engine.
A SIMPLIFIED construction of a wheeled trailer is described in specification No. 222,985, by the Eagle Engi
neering CO., Ltd. The frame of the trailer is hinged to the aide, and transmits the motive force direct, relieving the body of -all strain. There is a spring connection; between the body and the frame.
IN specification No. 222,077, General
. Motors Research Corp. describe a method of removing carbon from cylinder beads. A solution containing benzole, naphthalene and certain ether ingredients; is placed, in the cylinder while the engine is hot. The engine is then turned over several times and left for some hours. When the engine is subsequently started, the carbon is blown out through the exhaust.
TIME and distance-recording mechan ism for motor vehicles, of the type in which speed, total and trip mileage, and also time occupied during any one trip, are all shown on suitable dials, is described in specification No. 222%589, by C. M. H., Bath.