A dropped axle is the axle of a vehicle that is bent upwards towards the ends, i.e. the centre is 'dropped'. This gives two advantages: the centre of gravity of the bodywork is lowered relative to the wheels, which improves stability; secondly the wheels may be of larger diameter, giving a smoother ride over a rough surface.
Dropped axles were first used for carts: light two-wheeled horse-drawn vehicles. Their introduction represents one of the safety improvements from the high and unstable dog cart or jaunting car to the lower and more stable governess cart. Their ultimate development was in the float or milk float, where a dropped axle was used to give a low load bed for easy loading of churns or similar unstable liquid cargo.
A cart is a vehicle designed for transport, using two wheels and normally pulled by one or a pair of draught animals. A handcart is pulled or pushed by one or more people. It is different from a dray or wagon, which is a heavy transport vehicle with four wheels and typically two or more horses, or a carriage, which is used exclusively for transporting humans.
A jaunting car is a light two-wheeled carriage for a single horse, in its most common form with seats for two or four persons placed back to back, with the foot-boards projecting over the wheels. It was the typical conveyance for persons in Ireland at one time.
A governess cart is a small two-wheeled horse-drawn cart. Their distinguishing feature is a small tub body, with two opposed inward-facing seats. They could seat four, although there was little room for four large adults. The driver sat sideways on one of these seats. The centre rear of the body was lowered, or else had a small hinged door, and there was a step beneath. The wheels were of moderate size, always fitted with mud guards, and usually carried on elliptical springs. The axle was either straight or dropped, giving a low, stable, centre of gravity.
Cart wheels with dropped axle. Note that the weight of the springs has turned the axle upside down.
Dropped axles were made of forged wrought iron. Although wood was widely used for axles, owing to its lightness, it could not easily be shaped with the sharp curves required to drop an axle. Shaping such an axle by sawing or cutting would place an area of cross-grain across the upright part and would rapidly break.
Wrought iron is an iron alloy with a very low carbon content in contrast to cast iron. It is a semi-fused mass of iron with fibrous slag inclusions, which gives it a "grain" resembling wood that is visible when it is etched or bent to the point of failure. Wrought iron is tough, malleable, ductile, corrosion-resistant and easily welded. Before the development of effective methods of steelmaking and the availability of large quantities of steel, wrought iron was the most common form of malleable iron. It was given the name wrought because it was hammered, rolled or otherwise worked while hot enough to expel molten slag. The modern functional equivalent of wrought iron is mild or low carbon steel. Neither wrought iron nor mild steel contain enough carbon to be hardenable by heating and quenching.
As cars increased in speed after World War I, the use of a dropped front beam axle became almost universal, so as to lower the mass of their heavy front-mounted engines, improving stability when cornering. Rear axles were also beam axles, but needed to remain straight as they contained the halfshafts.
World War I, also known as the First World War or the Great War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously described as "the war to end all wars", it led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history. It is also one of the deadliest conflicts in history, with an estimated nine million combatants and seven million civilian deaths as a direct result of the war, while resulting genocides and the 1918 influenza pandemic caused another 50 to 100 million deaths worldwide.
A beam axle, rigid axle or solid axle is a dependent suspension design, in which a set of wheels is connected laterally by a single beam or shaft. Beam axles were once commonly used at the rear wheels of a vehicle, but historically they have also been used as front axles in rear-wheel-drive vehicles. In most automobiles, beam axles have been replaced by front and rear independent suspensions.
Axles were made of drop-forged H girder sections, so forging their upswept ends was a simple addition. To avoid creating stress risers, the drop was formed as smooth curves, not as sharp corners. Bugatti famously used a round bar for their axles, with the spring passing through holes within it and avoiding the U bolts that il patron found so ungainly. For further lowering, at the cost of reduced suspension travel, some axles were also prepared for racing by being mounted above the leafsprings, rather than below, although this was more common for straight rear axles than dropped front axles.
Automobiles Ettore Bugatti was a French car manufacturer of high-performance automobiles, founded in 1909 in the then-German city of Molsheim, Alsace by the Italian-born industrial designer Ettore Bugatti. The cars were known for their design beauty and for their many race victories. Famous Bugattis include the Type 35 Grand Prix cars, the Type 41 "Royale", the Type 57 "Atlantic" and the Type 55 sports car.
Ettore Arco Isidoro Bugatti was an Italian-born French automobile designer and manufacturer. He is remembered as the founder and proprietor of the automobile manufacturing company Automobiles E. Bugatti.
See also
Portal axle, geared hubs, used for the opposite effect to a dropped axle, so as to increase ground clearance for off-road vehicles.
Portal axles are an offroad technology where the axle tube is above the center of the wheel hub and where there is a reduction gearbox in the hub. This gives two advantages: ground clearance is increased, particularly beneath the low-slung differential housing of the main axles; and secondly the hub gearing allows the axle halfshafts to drive the same power but at reduced torque. This reduces load on the axle crownwheel and differential.
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Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition.
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In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels. For road vehicles with more than two axles, the wheelbase is the distance between the steering (front) axle and the centerpoint of the driving axle group. In the case of a tri-axle truck, the wheelbase would be the distance between the steering axle and a point midway between the two rear axles.
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A swing axle is a simple type of independent suspension designed and patented by Edmund Rumpler in 1903. This was a revolutionary invention in the automotive industry, allowing wheels to react to irregularities of road surfaces independently, and enable the vehicle to maintain a strong road holding. The first automotive application was the Rumpler Tropfenwagen, later followed by the Mercedes 130H/150H/170H, the Standard Superior, the Volkswagen Beetle and its derivatives, and the Chevrolet Corvair, amongst others.
Under the Whyte notation for the classification of steam locomotives, 4-4-4 represents the wheel arrangement of four leading wheels on two axles, four powered and coupled driving wheels on two axles, and four trailing wheels on two axles. In the United States, this arrangement was named the Reading type, since the Philadelphia and Reading Railroad was the first to use it. In Canada, this type is known as the Jubilee.
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The Canon de 19 C modèle 1875 was a coastal defense gun designed and built in the 1870s. A number of guns were also converted to railway guns during World War I in order to meet a need for heavy artillery.
