Excavator

An excavator is a piece of heavy construction equipment consisting of a boom, a dipper or stick, and a bucket mounted on a rotating platform called the house, used to dig and move earth, rock and other material. The excavator descended from the steam shovel, which was converted into the diesel- and electric-powered power shovel once operators replaced steam engines with internal combustion and electric motors, and modern excavators dig by pulling the bucket toward the machine the way a dragline does, rather than pushing it away as earlier powered shovels did. Hydraulic systems, using pressurized fluid to drive cylinders and motors, replaced the winches, chains and steel ropes of earlier cable-operated excavators, and in 1993 the manufacturer Yanmar introduced the first zero tail swing excavator, which keeps its counterweight within the width of its tracks as it rotates, improving safety in confined work sites.