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' magazine detailing the function of a four-cylinder, engine-operated Kellogg tyre pump.
| Identifier | ExFiles\Box 77\4\ scan0050 | |
| Date | 21th September 1912 | |
| H.H. 588a (160 H) (S.A. 801. 19-2-15) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 0950. THE AUTOCAR, September 21st, 1912. 519 EC 449 A Four-cylinder Tyre Pump. Operated by the Engine. THE modern tendency of motorists to avail themselves of the power of the engine for work other than the driving of the car is shown not only in the unusual amount of attention that is being given to self-starting devices put into a state for operation by the engine, such as those on the compressed air or the wound spring types, but also in apparatus to do other work, such as the inflation of tyres by mechanical means. One of the latest of these devices to make its appearance in this country is the Kellogg air pump, which, however, has been to the fore for some time in America, and is already used as a standard equipment on some of the leading cars in that country, while several manufacturers make a point of fitting it to order. Fig. 1.—The four-cylinder Kellogg pump. The Kellogg is a four-cylinder pump; in fact, it is nothing more than a tiny four-cylinder engine with the principle of its working inverted. In other words, instead of the pump crankshaft, driven by the pressure of gases in the cylinders, helping the car engine, the latter drives the pump crankshaft which, through its connecting rods and pistons, drives the gases—or rather air—out of the pump cylinders into the tyres. The accompanying illustrations nearly explain its principle of working. Having delivered air on the upstroke to the delivery pipe, the pistons move downwards from the top of the cylinders, but as the delivery pipe is fitted with a non-return valve a partial vacuum is formed in the space they leave in the cylinders on their downward travel; and it is only when the pistons reach the bottom of their down stroke and uncover the small holes C (figs. 1 and 2), seen near the bases of the cylinders, that a fresh supply of air is obtainable. Naturally, this air fills the partial vacuum rapidly, and as the piston again moves upwards with the rotation of the crank, the air thus obtained is compressed above the pistons and forced past the delivery valves and through the delivery orifice seen at A (fig. 2) to the hose and tyres. We have referred to the pistons being moved by connecting rods worked off a crankshaft; strictly speaking, however, they are worked by eccentrics, but the principle remains the same, since an eccentric is only a crank pin of such large diameter as to include the shaft within its circumference. The cylinder barrels are made of steel tube, but the casting at the top of the cylinders and the crank case are very cleanly run from aluminium, and thus the weight of the entire pump is kept down to a minimum; in fact, it only weighs about 4 lbs. The four cylinders are held in position by the two braces B (figs. 1 and 3) which, surrounding the boss of the main shaft bear- Fig. 2.—Crank or eccentric shaft of the pump, with cylinders. The bearings in which the shaft runs are also seen in the photograph. These are provided with keys fitting into keyways cut in the bearing seatings of the crank case to prevent their rotation. Fig. 3.—The main component parts of the Kellogg air pump crank case. The upper half is made in two parts, seen at each side, the one on the left showing its inside surface, that on the right its exterior. | ||