Aveling and Porter: Road Locomotive
Note: This is a sub-section of Aveling and Porter
Extract from Steam Locomotion on Common Roads by William Fletcher. Published 1891.
Messrs. Aveling and Porter, of Rochester, have during the last thirty-two years devoted themselves almost exclusively to the manufacture of traction engines ploughing engines, and steam road rollers, and during this period their name has been associated with numerous valuable patents relating to this branch of engineering.
In 1858, the late Mr Thomas Aveling designed and patented an arrangement for making portable engines self-moving, he applied a driving chain for communicating the power from the crankshaft to the axle, and in other ways modified the construction of Messrs. Clayton and Shuttleworth's engines, so that they would propel themselves from farm to farm, and haul a thrashing machine behind them. Judging by the testimonials given in Messrs. Aveling's catalogues of thirty years ago, many a portable engine was altered so as to do without horses, to the delight of the owners whom, we need scarcely add, after having one engine fitted with the loco- motive gear and front steerage, lost no time in ordering the necessary castings for altering the rest.
In some of the traction engines of these early times, a horse was placed in a pair of shafts for steering the engine along the road, but Mr. Aveling arranged a very simple steering gear, illustrated on a previous page in this book.
In 1860, Messrs. Aveling showed a chain traction engine at the Canterbury Show of the R.A.S.E., and at the London Exhibition, 1862. Referring to both these exhibits we quote the following from the firm's catalogue for 1863: " In the Exhibition of 185 1 there was not one traction engine, and it was the general belief that none could be contrived to answer any commercial purpose.
In the 1862 Exhibition nine of these engines were shown in the eastern annex. At the Royal Show at Canterbury, in 1860, Mr. Aveling exhibited a self-propelling engine — this was regarded with indifference by the officers of the society, and was catalogued with the miscellaneous articles. The Engineer in 1862, said "Mr. Aveling's traction engine is the best, we think, that has yet been produced"
In 1864 one of these road engines, named "El Buey," made for the Traction Engine Company of Buenos Ayres, hauled a load of 28 tons up Star Hill, at Rochester, which incline is 305 yards long, and rises one in twelve the whole distance; the engine also drew a train of 22 tons over soft ground in the locality of the Common, crossing a ditch 4.5 ft. wide and 2 ft. deep.
We should be delighted to follow up the history of Messrs. Aveling and Porter's many improvements, but we will briefly refer to an engine exhibited at Oxford, in 1870, and then leave the agricultural types to notice the quick-speed road locomotives.
Up to 1870 all the Rochester firm's engines were of the chain type, but the little five-horse power engine, shown at the Royal Show at Oxford, was driven entirely by gearing, and steered from the foot-plate. In this engine the ordinary cast-iron crankshaft brackets were dispensed with, the plates of the fire-box sides being carried upward and backward to serve the same purpose, and fitted with suitable bearings, while a neat cross casting served to render them perfectly steady.
About this time Mr. Thompson's road steamers were being made by Messrs. Burrell and others, fitted with rubber-tyred wheels, as previously described. We mentioned under Mr Thompson's name that the india-rubber was not a suitable material for taking any driving strain, it should only be used as springs. Fig. 68 shows the creep of the rubber tyre. Now, Messrs. Aveling and Greig's patent rubber-tyre wheel of 1870 was introduced to rectify this defect.
Figs. 88 and 89 show this wheel in section, from which it will be seen that the india-rubber is attached to the tyre of the wheel in segments, by a process patented by Messrs. Sterne and Co. The great advantage of this plan was, that if a segment got damaged it could easily and quickly be removed, and replaced by a spare segment at moderate cost. To avoid all possibility of slip in wet weather, and on clay soils, Mr. Aveling introduced the steel angle-iron crossbars» arranged so as to take the traction, without neutralising the benefit derived from the elastic action of the rubber. As the rubber yielded, affording the flexible broad bearing on the road, which was the secret of the success of the Thompson engine, the steel straps could slide between the intermediate guides. The rubber was thus protected; and from severe experiments carried out by Messrs. Aveling, the wheels tyred in this manner proved a success.
In 1871, Messrs. Aveling and Porter commenced to build high-speed road engines, specially equipped for military purposes, called "Steam Sappers" — engines of this type have been purchased by the French, Italian, and the English Governments. One was tested at the Wolverhampton Show of the R.A.S.E., having a cylinder 7.75 in. diameter and 10 in. stroke. The gearing ratio was seventeen to one. This engine was fitted with Mr. W. Bridges Adams's spring driving wheels, which are represented by the following illustrations: Fig. 90, shows a section of the wheel. Fig. 91 shows a pair of these wheels very clearly — one complete, and the other with one of the angle-iron rings removed so as to show the india-rubber blocks between the inner and the outer tyres. The spokes of the wheel are riveted to a strong tee-iron ring which forms the inner tyre, while outside this there is a hoop of sufficient strength, stiffened by an angle-iron ring, placed near each of the outer edges of the tyre, and provided on its face with the usual diagonal strips for giving the wheel increased adhesion. Between the inner tyre of tee-iron and the outer ring just described are inserted blocks of india-rubber, which are kept in place sideways by the angle-iron rings. These inner and outer tyres are connected by a drag-link clearly shown by the engravings, which prevents any friction taking place on the rubber blocks. This wheel is simple and has proved durable, but the cost of the india-rubber was too great to compensate for the advantages gained.
Messrs. Aveling have continued to build road engines suitable for running at a speed of five or six miles an hour with light loads, and slower when hauling heavy loads, as used by various Governments. These military engines or "steam sappers" have been of Messrs. Aveling’s standard types, slightly modified to suit the requirements, and they have given the utmost satisfaction.
We must now describe the fine road locomotive introduced in 1878, one of which was shown at the Bristol Show of the R.A.S.E., and another at the Paris Exhibition of that year. One of the chief features of the engine was the arrangement of the gearing inside the bearings, and not on the overhanging ends of shafts outside the bearings. Everyone acquainted with the working of gearing subject to very heavy strains will know how to appreciate this improvement; the bearings are more fairly worn, and the gearing is maintained rigidly in truth. Another important gain in the arrangement patented by Mr. Aveling, is, that at the same time small pinions and large spur wheels are alike dispensed with, the employment of an intermediate shaft, securing the reduction of speed between the crank- shaft and the driving wheels. The slow gear ratio being 26 to 1. This engine was fitted with Messrs. Aveling's patent crankshaft brackets, which are formed out of the side plates of the fire-box extended upwards and backwards, carrying the crankshaft, countershaft, and driving axle bearings in one plate.
The driving wheels are 7 ft. in diameter, and 16 in. wide on face, and are constructed of a specially strong section of tee iron. The winding drum on the hind axle is capable of holding 100 yards of 0.75 in. diameter wire rope, the compensating gear wheels are of large size. The boiler was intended for a working steam pressure of 150 lbs. per square inch, the fire-box stays being pitched four inches apart.
Fig. 92 gives a plan of the gearing, while Fig. 93 shows a transverse section through the hind part of the engine. From these views it will be seen that the whole of the crankshaft and countershaft gearing is arranged to work between the wrought iron brackets, and the fly-wheel is fixed close to the crankshaft bearing. The pinions for the two speeds are keyed fast upon the crankshaft, instead of sliding on "feathers," the arrangement for altering the speed is shown in plan Fig. 92. The intermediate shaft is fixed, and serves as a stay to the side plates, and the sliding sleeve, which carries the spur wheel and the fast and slow speed pinions, revolves on it. The two crankshaft pinions are of the same size, and the intermediate spur wheel gears with one or the other, as required.
When the parts are in the position shown in the plan, the engine is in its fast gear; but if the sleeve be moved to the right, the other crankshaft pinion comes into gear; also the right hand sleeve pinion gears into the right hand spur wheel upon the countershaft, and the engine is in slow speed. The engine is stronger, narrower, more compact in consequence, and the wear and tear most certainly reduced.
Without staying to refer to many details of interest, we pass on to notice another arrangement of gearing exhibited by Messrs. Aveling and Porter on one of their traction engines at the Smithfield Show, 1883. Fig. 94 shows this arrangement of inside gear, kindly supplied by the proprietors of Engineering from which it will be seen that the crank-shaft carries two pinions a and b keyed fast on it The intermediate shaft is fixed, and on it turn the two wheels c and d and the long pinion, the two wheels just named being cast together and bolted to the pinion. In the positions shown in the engraving the engine is in slow gear, the pinion b on the crankshaft engaging with the wheel d on the intermediate shaft By means of the clutch and lever shown, however, the wheels and pinion c d and e can be slid to the left along the intermediate shaft so 'as to make the wheel c gear into the pinion, and thus get a faster motion, the pinion c being of such a length that it remains in gear with the wheel f.
Fig. 94 also shows Messrs. Aveling and Porter's cast-iron plate bracket for carrying the crankshaft, fixed intermediate shaft and countershaft bearing. It will be seen that these cheeks are secured to the outside of the fire-box side plates, and have flanges provided for bolting the transverse plates to them, making a sound and thoroughly mechanical job.
It is impossible to speak too highly of the well-designed and latest pattern road locomotive shown by Fig. 95. The cylinder is thoroughly steam jacketed, and placed as near the smoke-box as possible. The side plates of the fire-box shell are carried upwards and backward for taking the four bearings of the various shafts. The first and second motion gearing is placed inside the bearings as before. An extra tank is provided beneath the boiler barrel, connected by a pipe with the tank under the foot-plate. The working parts of the engine are neatly boxed in, and the fly-wheel is of the disc pattern so as not to frighten horses. The driving wheels, compensating gear and draw bar are all exceedingly strong, and intended for rough usage and continuous road haulage work. Messrs. Aveling and Porter's road locomotive and dynamo are shown by Fig. 96 — engines of this type were sent to Suakim for military purposes.
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