Concept
A steamroller (or steam roller) is a form of road roller – a type of heavy construction machinery used for leveling surfaces, such as roads or airfields – that is powered by a steam engine. The leveling/flattening action is achieved through a combination of the size and weight of the vehicle and the rolls: the smooth wheels and the large cylinder or drum fitted in place of treaded road wheels. The majority of steam rollers are outwardly similar to traction engines as many traction engine manufacturers later produced rollers based on their existing designs, and the patents owned by certain roller manufacturers tended to influence the general arrangements used by others. The key difference between the two vehicles is that on a roller the main roll replaces the front wheels and axle that would be fitted to a traction engine, and the driving wheels are smooth-tired. The word steamroller frequently refers to road rollers in general, regardless of the method of propulsion. Before about 1850, the word steamroller meant a fixed machine for rolling and curving steel plates for boilers and ships. From then on, it also meant a mobile device for flattening ground. An early steamroller was patented by Louis Lemoine in France in 1859 and demonstrated sometime before February 1861. In Britain, a 30-ton steamroller was designed in 1863 by William Clark and partner W.F. Batho. Having failed to impress the British municipal road authorities it was transferred to Kolkata where it continued to work. The company Aveling and Porter was the first to successfully sell the product commercially and subsequently became the largest manufacturer in Britain. In 1866 they produced a prototype roller with 3 foot-wide rollers fitted to the rear of a standard 12 nominal horsepower traction engine. This experimental machine was described by local papers as 'the world's first steamroller' and it caused a public spectacle. In 1867, the steam road roller was patented and the company began production of the first practical steam roller – the new machine's rollers were mounted at the front instead of the back and it weighed in excess of 30 tons.
