Motor Scraper

Overview

A motor scraper is a self-propelled earthmover that performs four jobs in one pass: it cuts a thin slice of soil, loads it into a bowl carried between its axles, hauls it at road speed, and spreads it back out in a controlled layer at the fill. Because it both digs and hauls, it removes the need for separate excavators and trucks on large cut-and-fill jobs such as highway grading, dams, and airfields, and it lays material in even lifts ready for compaction.

The machine splits into a front Tractor Unit that carries the engine and cab, connected through a Gooseneck & Hitch to the Scraper Bowl riding on the rear axle. Power flows from the Diesel Engine through the Powershift Transmission to the wheels.

How it works

To load, the operator lowers the Scraper Bowl until its Cutting Edge bites into the ground and raises the Apron at the front of the bowl. As the machine drives forward, soil shears off and is forced up into the bowl; the apron then closes to trap the load. The bowl is raised for travel, and at the fill the apron opens while the Ejector, a moving wall inside the bowl, pushes the load out evenly over the cutting edge, which is now set to spread rather than cut. All of these motions are driven by the Hydraulic Cylinder actuators fed from the Hydraulic System.

The single Diesel Engine is a large turbocharged diesel. Its torque passes through a torque converter and the Powershift Transmission, an eight-speed powershift, to the tractor's drive wheels. Because a loaded scraper is hard to fill in poor traction, many jobs use a pusher dozer or a paired scraper to push during the cut.

Steering articulates the Gooseneck & Hitch: the Steering Cylinder pair swings the whole tractor relative to the bowl, giving a tight turning circle for such a long machine. The operator works from an enclosed Operator Cab with a display for transmission, payload, and engine data, and a low-voltage Electrical System system runs the lights and controls.