Information AboutSteamroller |
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A steamroller (or '''steam roller''') is a form of Road Roller – a type of heavy construction machinery used for levelling surfaces, such as roads or airfields – that is powered by a Steam Engine . The levelling/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. steamroller]] The majority of steam rollers are outwardly similar to Traction Engine s 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 Wheel s and axle that would be fitted to a Traction Engine . In many parts of the world, the term ''steam roller'' is still used to refer to a Road Roller , regardless of the method of propulsion. This typically only applies to the largest examples (used for road-making). This article concentrates on steam-powered rollers; see Road Roller for a description of motor (eg diesel) rollers. CONFIGURATIONS The majority of rollers were of the same basic configuration, with two large smooth wheels at the back and a single wide roll at the front. However, there was also a distinctive variant, the tandem, which had two wide rolls, one front, one rear (see photo ). This configuration is still used frequently for small motor Road Roller s for use on minor pavement and road repairs. Another variation was the convertible: a combined engine which could be either a steam roller or a traction engine and could be changed from one form to the other in a relatively short time – i.e. less than half a day. Convertible engines were liked by local authorities since the same machine could be used for haulage in the winter and road-mending in the summer (for example). DESIGN FEATURES Although most steam roller designs are derived from Traction Engine s, and were manufactured by the same companies, there are a number of features that set them apart. Wheels The most obvious difference is in the wheels. All traction engines were built with large fabricated spoked steel wheels with wide rims. Those intended for road use would have continuous solid rubber 'tyres' bolted around the rims, to improve traction on tarmac. Engines intended for agricultural use would have a series of 'strakes' bolted diagonally across the rims (like the tread on a modern pneumatic tractor tyre), and the wheels were typically wider to spread the load more evenly. Steam rollers, on the other hand, had smooth rear wheels and a roller at the front. The roller was a single wide cylinder supported at either end. This replaced the separate wheels and axle of a traction engine. Smokebox In the conventional arrangement, the front roller is mounted centrally, forward of the chimney. In order to allow enough clearance from the boiler (and hence a larger front roll), the Smokebox is extended forward substantially at the top to incorporate a support plate on which to mount the bearing for the roller assembly. This gives the distinctive 'hooded' look to the front of a steam roller. It also necessitates a different design of smokebox door – it has to drop down, rather than opening sideways, due to the limited access available. Special equipment The rear rollers were fitted with scraper bars. As the vehicle moved along, these removed any surface material that had become stuck to the roll, to prevent a build-up of material and ensure a flat finish was maintained. Some steam rollers were fitted with a scarifier mounted on the tender box at the rear. They could be swung down to road level and used to rip up the old surface before a road was remade. Another 'extra' was a tar sprayer - a bar mounted on the back of the roller. This was not a common fixture. USE (UK) A number of companies owned fleets of steam rollers and contracted them out to local authorities. Many were still in use into the 1960s, and part of the M1 Motorway was made with the help of steam rollers. |
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