Wheel tractor scrapers: load, haul and spread in one machine

A wheel tractor scraper is a self-propelled earthmover with a large bowl between its axles. As it drives forward, the bowl's cutting edge slices a thin layer of soil, filling the bowl. The scraper then hauls the load at speed and spreads it in an even layer at the fill area. One machine does the work of an excavator, a truck and a dozer.

Today the market is dominated by Caterpillar, the only major manufacturer still offering a full range of self-propelled scrapers. Tractor-towed (pull) scrapers are also common in agriculture and land levelling.

Types of scrapers

• Single-engine, open-bowl scrapers usually need a push from a dozer to load fully.
• Twin-engine scrapers have a second engine driving the rear wheels for traction on grades and soft ground.
• Elevating scrapers use a chain elevator to load themselves without a push tractor.
• Push-pull scrapers connect two twin-engine scrapers with hitches so they help each other load.

When scrapers make sense

Scrapers are most efficient for large-volume earthmoving over haul distances of roughly 150–1,500 m (500–5,000 ft): highway construction, dams, land development and mine reclamation. In suitable soils they offer one of the lowest costs per cubic metre of any earthmoving method.