The scrapers are highly efficient machines which are used for a variety of construction tasks. They are designed to reduce the operations costs, and to increase the productivity on the job site. The scrapers are heavily used for road construction projects when a firm surface needs to be prepared.
Designed to load, haul and dump loose material, the scrapers are capable to handle a variety of materials, ranging from fine-grained soils to rocks left from demolition work. Beside construction, the scrapers are commonly used for excavation and embankment work.
A typical scraper is consisted of two components: a tractor and a bowl (a large bucket with an opening on the front side). The tractor holds the engine and the operator’s cab, and it is designed with two axles. The bowl is suspended from the frame between the front and rear axles. For a better maneuverability, the scraper tractors are mounted on rubber-tires. With such tires, the scrapers are capable to achieve speeds of 45 Km/h while caring a full load.
Different scrapers are available on the market, and they vary depending on their configuration and specifications. The most common scrapers are: push-pull, push-loaded and elevating.
Push-Pull Scrapers. The push-pull models come with a push block and bail which is mounted on the front of the scraper. A push block and a hook is mounted on the rear end. This model is actually consisted of two scrapers which are connected together. The two scrapers are attached by the hook and bail. The working principle is quite simple: as the rear scraper push, the front scraper loads.
Push-Loaded Scrapers. This model is pushed by a bulldozer while loading. When both forces are combined (the bulldozer and the scraper force), they ensure that the bowl is being loaded to its full capacity.
Elevating Scrapers. These machines come with a chain elevator that serves as a loading mechanism. The working principle is: as the scraper moves forward, the elevator moves the material into the bowl. However, this model cannot handle rocks, and additional weight tends to slow down the machine.
For long, the scrapers have been considered as the most efficient machines for moving large volume of materials. Moreover, the manufactures try to make constant improvements in the design and the manufacturing process have been allowing more and more efficient models, able to implement greater productivity and potential profits in any construction site.