• A NEW PNEUMATIC TYRE.
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A Résumé of Recently Published Patents.
We have from. time to time, in the general news or editorial columns of this journal, expressed' the opinion that important developments in regard to the methods ofespringing" of 'motor vehicles are bound to develop in-the near future. It is generally anticipated that the improvements will probably be effected in the actual design, construction or arrangements of the road springs. An ale terna-tive,solution lies in the oonstruetion of the tyres, and it is clear that one of the best shock-absorbing mediums is the pneumatic tyre, biit as a rule the possibility of much improvement in this direction, although not by any minus-to be ruled entirely out of court, has nevertheless been regarded. a.se .unlikely on practical grounds. There is probably nothing in actual fact to account for this attitude, except the knowledge of the effort that has continually been expended ever since the motorcar came-into being on improvement of this important -part of the ear's anatomy; and the consequent belief that all, or nearly all that can be done has been accomplished.
The belief in this finality, as regards the present type of tyre, has neverbeen held, at least, by Mr. E. B Killen, who is well known in oonnection with various inventions in respect of tyres, and considerable interest undoubtedly will be extended to his latest effort in this direction, which is exemplified in specification No. 139,930.
There are two outstanding features in the construction of this tyre. First, there is the strength of the casing, which, we are informed, is of coed, actually woven to shape in one piece. It is claimed, that although it may be, and preferably is, made of a thickness only half of that customary on ordinary pneumatic tyres, it has nevertheless twice the strength of that of the normal tyre. Secondly, there is the construction of the "wide, supple, gab-le-like tread," which, by reason of its suppleness and shape, affords a .greater circumferential bearing surface on the road, and by, lies width protects the walls of the tyre from damage by stones or other sharp obstruction, C48i encounters with which, as we know to our cost, are the frequent but unfortunately unavoidable experiences of all who travel by road. The increased circumferential contact with the road surface, afforded by the tyre, allows of its carrying a load greater in proportion to itssize than that•which can safely be carried by the ordinary pneumatic. Owing to the thin walls of the tyre, and the flexible nature of the tread, it accommodates itself much.
more readily and extensively to changes in the loading, whether those changes -are brought about gradually or .rapidly, so that, as a matter of fact, the increased area. of contactis largely in proportion to the load.
When a.stone is encountered, owing to the flexibility of the tread, the shock of the encounter, we are informed, is spread over, and accommodated bye a much larger area of the tyre. sham in the ordinary case, and there is cerreetpiently less danger of local damage to the casing. When the rising edge of a large pot-bole or similar obstruction is struck, the tyre, as illustrated in one of the drawings which we reproduce, is almost flattened out. It is claimed that this extreme distOrtion is accomplished without any harm to the tyre, and that the walls are so constructed as to be able to -withstand
this trearnent as a regular thing without offering any protest.
Indeed; owing to the extent of this allowable deflection, it is seriously suggested that it will be practicable, at least on small -chassis, entirely to eliminate the need for the ordinary type of road spring, and rely entirely on the tyro to absorb all shocks. Such aie achievement as this, if it proves possible, will Imo doubteily cause a small revolution mt chassis construction, and'should go far to reduce the cost of construction.
The cross section of the tyre, with the above-named reservations as to walls and tread, may be the same as that of the usual pneumatic, but the shape shown IC our illustrations is preferable for several reasons. It economizes the material of the walls, and owing to its comparative shallowness—a Win, tyre need be only 8 ins, deep, for example—it allows of a large size of wheel.
Space does not permit of a consideration of the details of the construction of the tyre, but a reference to the specification will be well worth the while of mdst of our readers.
Detail Improvements.
The engine crank, in the construction deecribed. by T. G. J-u.ngersert, in speci
fication No. 129, 283, is noteattached to the shaft., but drives the flywheel through the medium of a pair of equal gears, ar ranged as epicyclic gearing. The effect is to vary the length of the strokei of the piston so that the suction and compres sion strokes are only about one-third the length of the expansion and exhaust strokes. It is claimed that by this means more effective use is made of the available work in the exploded gases.
What appears to be a new principle in ploughs is embodied in the garden culti vator, which is the subject of a patent, No. 140,000, by A. R. W. Marshall.
A "furrow cutter" is poeitioned ad vance of the ploughshare, and is reciprocated from the engine, acting through gearing and a connecting rod. The same connecting rod drives the ground wheel of the machine by ratchet and pawl gear, i the action being (1) a' thrust s given to the furrow cutter on one stroke Of the connecting rod, and (2) on the other stroke the machine is propelled forward.
No. 139,911 refers to the construction of four-wheel drive chassis. The object appears tobe the elimination of a reduction in gear and some universal joints. The patentee is 0. Imray.
H. F. Foster, in No. 139,899, makes the inner member of a. friction clutch in two segments, which together are bored to fit upon an eccentric boss. Springs between the ends of the segments wedge the segments into driving contact with the flywheel, and they are separated when required by mechanical means.
Mechanical opening and closing of poppet valves is effected by B. G. cat
tense, in No. 122,180, by locating the -valve-operating rocking levers between two cams, on •parallel shafts.
No. 140,014describes a. method of wholly or partially choking the petrol
pipe to prevent unauthorized use of a car, the patentee being C. A. Beveridge, and No. 140,022, by Beardmore and Co., has reference to a telescopic type of universal coupling.