1. Trang chủ
  2. » Kỹ Thuật - Công Nghệ

An Encyclopedia of the History of Technology part 47 pdf

10 336 0

Đang tải... (xem toàn văn)

THÔNG TIN TÀI LIỆU

Thông tin cơ bản

Định dạng
Số trang 10
Dung lượng 515,37 KB

Nội dung

PART THREE: TRANSPORT 442 antagonism. Trevithick’s steam transport experiments were thenceforth confined to rails. In 1804 a locomotive of his design drew a load of some 10 tonnes and 70 men the 15.5km (9.75 miles) from Penydaran to Abercynon, South Wales, in just over four hours. It was Trevithick’s use of high pressure steam, rather than Watt’s self-imposed restriction to atmospheric pressure working, that allowed the development of locomotion. BICYCLES The idea of using human muscular effort for the propulsion of light road vehicles seems to originate as early as Roman times but, apart from spasmodic experiments, was not seriously developed until the late eighteenth and early nineteenth centuries. The hobby-horse (or dandy-horse) era took off in 1817 when Baron Karl Drais von Sauerbronn of Mannheim demonstrated his ‘Draisine’ in the Luxembourg Gardens in Paris. It had a wooden frame, a steerable front wheel, and an armrest behind the handlebars which gave the rider a greater purchase in thrusting his feet against the ground. In spite of the inefficiency of this awkward method of propulsion, a journey from Beaune to Dijon, a distance of 37km (just over 23 miles) could be made by Draisine in 2 1/2 hours, an average speed of 15kph or nearly 9 1/2mph. The popularity of the vehicle as a fashionable novelty, rather than a practical means of transport, led to its rapid adoption in other countries as well as France, particularly England (see Figure 8.5), Germany and the USA. Figure 8.3: Nicolas Cugnot’s steam Traction Engine built in 1769 to draw artillery. ROADS, BRIDGES AND VEHICLES 443 The first man to appreciate the gyroscopic effect of two wheels mounted in line and the possibility that it gave of lifting the feet from off the ground was Kirkpatrick Macmillan, a blacksmith of Courthill, Dumfriesshire. In 1839 he invented and built the world’s first pedal-operated bicycle (Figure 8.6). A curved wooden backbone carried the rider and a saddle, the front wheel being steerable. The iron-tyred wooden wheels were carried on brass bearings, the drive to the rear wheel, which had a pair of cranks keyed to the axle driven by connecting rods, being from two swinging levers, pivoted ahead of the rider and ending in pedals for the rider’s feet. Macmillan often rode his machine on the 22.5km (14 miles) stretch between Courthill and Dumfries and the 64km (40 miles) to Glasgow. In spite of the blacksmith’s success and that of a number of copyists, the machine did not catch on and experiment in the following twenty years was largely confined to tricycles and quadricycles. Figure 8.4: Richard Trevithick’s steam carriage of 1802. Little public interest was shown and Trevithick turned his attention to rail locomotion. PART THREE: TRANSPORT 444 Figure 8.6: Kirkpatrick Macmillan’s bicycle of 1839. For the first time, the rider’s feet were off the ground. Figure 8.5: An early ‘hobby horse’ of 1818. ROADS, BRIDGES AND VEHICLES 445 Soon after 1860 the boneshaker made its appearance, basically a variant of the velocipede of Pierre Michaux of Paris. The frame or backbone was of wrought iron and the drive was by pedals keyed directly to the axle of the steerable front wheel (Figure 8.7). The machine incorporated a brake, a lever on the frame pressing a shoe against the periphery of the rear wheel tyre. By 1865 Michaux was building over 400 machines a year which sold for around £8. The first bicycle journal in the world was started at Grenoble in 1869, and the first cycle show took place in Paris in the same year. Wire spoked wheels, tubular frames, solid rubber tyres, mudguards, freewheels and change-speed gears were among the different features on the machines exhibited. French superiority in the bicycle industry was to last until the outbreak of the Franco-Prussian War in 1870. It was Coventry that was to become the centre of the industry in England, with an early example of both exporting and diversification. The Coventry Sewing Machine Company had received an order for 400 bicycles for France, an export frustrated by the 1870 war. They decided to explore the market in Britain, with some success, and managed to dispose of the stock made for the French order. In the following ten years the diameter of the front wheel, already larger than the rear wheel, was gradually increased, the rear wheel Figure 8.7: Pierre Michaux’s Velocipede of about 1863 was a hobby horse with pedals fixed to the front wheel. PART THREE: TRANSPORT 446 becoming smaller while the saddle of successive models moved forward until the rider was poised directly above the front axle. In this position he could use his leg power and body weight most effectively. Thus was developed the ordinary bicycle as it was then called, more frequently referred to today as the penny-farthing. In this, the radius of the front wheel was about equal to the length of the rider’s leg. The problems of mounting a 183cm (6ft) diameter wheel required considerable skill, as did staying there—and dismounting with a degree of decorum. Figure 8.8 illustrates an example of this variety of bicycle. In the 1870s and 1880s development was to evolve the safety bicycle (Figure 8.9), forerunner and prototype of the machine we know today, with equal-sized front and rear wheels, the rear one being driven by a chain and sprocket. The diamond frame of tubular steel became standard after 1900 and the pneumatic rubber tyres of J.B.Dunlop after 1893 (see p. 449). Figure 8.8: Starley & Hillman’s ‘Ariel’ of 1870. ROADS, BRIDGES AND VEHICLES 447 MOTOR CYCLES A little-noticed event happened in December 1868, when a small single- cylinder Perraux steam engine and boiler was fitter to a Michaux velocipede. Thus the first truly successful bicycle became the basis for the first motor cycle, starting a separate line of development that was ultimately to lead to the age of the motor car. This was by no means the first time that such a machine had been suggested: it was a favourite subject for cartoonists, such as Leech, Rowlandson and Cruikshank from about 1820. It led to no commercial development but was undoubtedly the prototype of the motor cycle. Perhaps its most successful follower was the steam tricycle made by L.D.Copeland of Philadelphia in 1884, of which some 200 were built. Progress had to wait for the invention of the internal combustion engine, particularly that of Gottlieb Daimler, who produced a two-wheeler of remarkably primitive aspect driven by an air-cooled four-stroke petrol engine in 1885. His interest in motor cycles soon waned and he devoted himself, as did Karl Benz, to cars (see p. 450). In 1895 Count Albert de Dion and Georges Bouton, pioneers of steam-driven vehicles for twelve years, produced their first light-weight, high-speed petrol engine and soon fitted it to a tricycle. It ran at 1500rpm, compared to Daimler’s 800rpm, weighed 18kg (40lb) and generated 1/2hp. A 13/4hp de Dion Bouton tricycle was Figure 8.9: Humber Safety Bicycle, 1890. PART THREE: TRANSPORT 448 first in its class in the Paris-Marseilles-Paris road trial of 1896, averaging 22.5kph over the 1126km course. They licensed many foreign firms to manufacture their engines, as did Daimler. By 1900 over fifty companies in England were building motor bicycles or tricycles. Most of the early models kept strictly to the diamond- shaped frame of the ‘safety’ pedal bicycle. Coventry was again the centre of the industry which really took off with the repeal of the ‘Red Flag’ Act in 1896, a maximum speed of 12mph (19kph) then becoming permissible. At first manufacturers tended to concentrate their efforts on the production of tricycles and quadricycles so that motor-cyclists could obtain the freedom of movement offered by the motor car but with a lower initial expenditure and at reduced running cost. These multi-wheeled cycles had the sociable advantage over the motor bicycle that they could carry a passenger. However, development along these lines virtually ceased with the invention of the sidecar by W. G.Graham in 1903. The first really practical two-wheeler was produced by Michel and Eugène Werner, two Paris journalists, in 1897. It was little more than an engine-assisted bicycle, with the engine mounted on the handlebars and driving the front wheel. This arrangement was somewhat top-heavy and in 1901 the Werners as well as Messrs Phelon and Moore and others started to build machines with the engine mounted low in the frame and driving the rear wheel by belt or chain, thus establishing the classic layout of motor bicycle used still today. The motor bicycle movement had begun, with popular competitions and trials. Among these was the Tourist Trophy, or TT, races held annually on the Isle of Man, as racing on the public roads of mainland Great Britain was illegal, as it remains today (except for the occasional event licensed by local bye-laws). The first TT was held in 1907 when the winner was a Norton, and this gave a notable boost to the British motor cycle industry. An American ‘Indian’ won in 1911 with similar benefit to the United States manufacturers. By 1914 the motor-cycle speed record stood at 150kph (93.5mph). Further development was curtailed by the outbreak of the First World War, the production of machines, except for war purposes, being prohibited after 1915. Many motor-cyclists of the period found employment for their talents as the first army dispatch riders and rendered sterling service throughout the war. The TT races were re-established in 1920, British motor cycles remaining dominant until 1951 when, for a decade, the Italian makers—Moto-Guzzi, Gilera and M.V.Augusta—took the lead with the German firm NSU. From the early 1960s the Japanese Honda became supreme, by which time the British motor cycle industry was but a shadow of its former glory when, as in 1937, a 1000cc Brough Superior with a JAP engine held the world speed record at 273kph (170mph). In 1978, at Bonneville Flats, Utah, a two-litre Kawasaki Special reasserted the supremacy of the Japanese industry by taking the world speed record at 512.6kph (318.5mph) —a far cry from Ernest and Pierre Michaux’s alcohol-fuelled steam cycle of 1868. ROADS, BRIDGES AND VEHICLES 449 The period after the Second World War introduced a general need for fuel economy which did much to promote the moped and the autocycle. The first of the former, in the early 1950s, was the 50cc NSU from Germany, followed shortly by the Italian Vespa and Lambretta machines, with small wheels, 125cc engines and a front apron affording some protection against the weather for the rider. The design of the moped originated in the folding scooters such as the Corgi used by paratroops during the war. Another development of the same period, in vogue for some years, was the bubble-car. Heinkel and Messerschmitt were both prominent makes of these machines, the designs of which owed much to the cockpits of the aircraft which these companies had been building during the war. The passenger sat unsociably behind the driver; more sociable—and more bubble-shaped—was the BMW machine in which side-by-side seating was provided. Still in Germany, a possible resurgence of the three-wheeled bubble-car was revealed by the Volkswagen Research Division in a design study of early 1986. This vehicle was said to have a maximum speed of 193kph (120mph) and a fuel consumption of only 21.2km/l 59.9 miles per gallon (49.9 US) with a 1.4l engine. Its road-holding at speed was said to be superior to that of the same company’s Golf saloon. THE MOTOR CAR It is unfortunate, perhaps even unfair, that so many inventions are ascribed to those who brought them to full commercial fruition rather than to those who were their true originators. Just as James Watt was the great improver of Thomas Newcomen’s rather inefficient steam engine, those whose names are usually associated with the invention of the motor car had their forerunners, while the same applies to many of its component parts. Rudolph Ackermann, a London printseller, for instance, patented the form of steering known since then by his name. In fact, it was invented for windmill carriages just over a hundred years earlier in 1714 by Du Quet, whose name is virtually unknown. Likewise, John Boyd Dunlop is credited with inventing the pneumatic tyre in 1888 (he fitted them to the rear wheels of his small son’s pedal tricycle) and was the first to bring it into general use on any appreciable scale, with the formation of the Pneumatic Tyre Company, later to become the Dunlop Company. In fact R.W.Thompson’s ‘aerial tyres’ were also pneumatic and have been in use for horse-drawn carriages from 1845. While Gottlieb Daimler and Karl Benz can claim to be the first to exploit petrol-engined motor cars from 1886, Siegfried Marcus had some success in running a petrol-driven four-wheeler vehicle in Vienna in 1875 (see Figure 8.10). Unfortunately the Viennese police objected to the noise it made and, as it was to Marcus no more than an engineering exercise, he did not persist PART THREE: TRANSPORT 450 in its development. In fact, both Daimler and Benz were almost preceded by Edward Butler, a London engineer, who patented a three-wheeled ‘petrol cycle’ in 1884, but did not have it running until 1888. It differed from Benz’s ‘Patent Motor Wagon’ (see p. 38, Figure 8; p. 451) in having two steerable wheels at the front and a single driving wheel at the rear. Two horizontal water-cooled cylinders drove overhung cranks on the axle of this wheel drawing petrol from a spray carburettor which was fired by an electric spark. Numerous trials and demonstration runs were made but the lack of enthusiasm of his financial backers and the restrictive road laws in Britain at the time defeated Butler. He broke up his machine and sold the brass and copper for scrap in 1896—ironically the very year that the laws relating to road vehicles were relaxed. Thus it is to Daimler and Benz that the credit must be given for building the first motor cars to go into production and to become both a technical and a commercial success. Although they lived only some 96km (60 miles) apart, neither man knew anything of the other’s early experiments; ultimately they were to combine forces as Daimler Benz, later Mercedes Benz. Gottfried Daimler, of Cannstatt near Stuttgart, invented the light, high-speed petrol engine in 1884 and in the following year built his ‘quadricycle’, a curious, wooden-framed motor cycle with a pair of small side wheels mounted on out- Figure 8.10: Model of Siegfried Marcus’ Motor Car of 1875. ROADS, BRIDGES AND VEHICLES 451 riggers to prevent it from overturning, such as are sometimes used on a child’s fairy cycle today. Also in 1885, Karl Benz built his first model, a three-wheeled ‘Patent Motorwagen’, which ran in the streets of Mannheim in 1886; its engine was of 984cc and produced 0.9hp (673W) at 400rpm (see p. 38). In the same year Daimler fitted a 469cc engine to a Victoria carriage, working at up to 700rpm and generating 1.1kW (1.5hp). With Wilhelm Maybach, whose spray carburettor contributed so much to the success of his engine, Daimler started building cars in 1899. Benz produced four cars for sale but found difficulty in attracting buyers. His French agent, Emile Roger, had more success, while Daimler granted licences to both Peugeot and Panhard-Levassor in France to build his latest two-cylinder 1.65hp engines in 1889. Further French interest was shown by the entry of Michelin into the pneumatic tyre market in 1894–5, de Dion Bouton, who adopted Robert Bosch’s electric ignition in 1897, and Renault, who built the first car with shaft drive in 1898. The first American car was built by the Duryea brothers in 1893, while Fiat started the industry in Italy with a car driven by a twin horizontally-opposed cylinder engine in 1899. A significant feature of the early development of the motor car and the internal combustion engine is the relatively small contribution made by British engineers, especially in comparison with their major role in the history of the steam engine and its application to the railway locomotive (see Chapter 11). The plain reason was parliamentary obduracy, which confirmed public apathy by imposing draconian laws on the operation of motorized road vehicles. The ‘Red Flag’ Act, passed in 1865, required that ‘at least three persons shall be employed to drive or conduct a locomotive’ on the public roads, a locomotive meaning anything from an agricultural or showman’s steam tractor to a three- wheeled, petrol engine car. One such person ‘shall precede each locomotive on foot by not less than 60 yards carrying a red flag constantly on display’, the law declared. A speed limit of 4mph (6.5kph) was also stipulated and, though the red flag was no longer a requirement after 1878, the pedestrian advance warning was still legally necessary until the Act was finally repealed in 1896, an event commemorated annually today in the London to Brighton Veteran Car Run. The lead of the French is shown by the fact that in the previous year a race from Paris to Bordeaux and back (1178km) (732 miles) had been won by Emile Levassor in a Panhard-Levassor at an average speed of 24kph (15mph). The speed limit in Britain was still only 12mph (19kph). Naturally there was much opposition to the British laws. Notable was Sir David Salomans of Southborough, who had built an electrically-propelled tricycle in 1874, was one of the promoters of the Self-Propelled Traffic Association in 1895 and organized the first ‘motor show’ in the country, held in Tunbridge Wells in October of that year. Flouting the Red Flag Act, Sir David drove to the show from Southborough in a Peugeot with an engine of Daimler manufacture to join the other three cars that were on display. . Heinkel and Messerschmitt were both prominent makes of these machines, the designs of which owed much to the cockpits of the aircraft which these companies had been building during the war. The passenger. time, the rider’s feet were off the ground. Figure 8.5: An early ‘hobby horse’ of 1818. ROADS, BRIDGES AND VEHICLES 445 Soon after 1860 the boneshaker made its appearance, basically a variant of the velocipede. 1870 war. They decided to explore the market in Britain, with some success, and managed to dispose of the stock made for the French order. In the following ten years the diameter of the front

Ngày đăng: 04/07/2014, 01:20

TỪ KHÓA LIÊN QUAN