A powerful machine used for moving earth, rocks, or debris, the bulldozer is employed worldwide in road building, construction, demolition, and farming. It is distinguished by its movable broad steel blade and tractorlike design. A powerful diesel engine drives the machine.
Bulldozer is an earth-moving machine. It consists of a large, steel blade attached to the front of a tractor. The term is also used to mean the blade alone. The blade is mounted on a tractor that has either rubber tires or endless tracks like those of a battle tank. The driver can raise or lower the blade with a power control. Bulldozers are major tools in grading and excavating land for construction projects of all sizes, including earth dams, highways, railroads, and airports.
Also called a Dozer, powerful machine for pushing earth or rocks, used in road building, farming, construction, and wrecking; it consists of a heavy, broad steel blade or plate mounted on the front of a tractor. Sometimes it uses a four-wheel-drive tractor, but usually a track or crawler type, mounted on continuous metal treads, is employed. The blade may be lifted and forced down by hydraulic rams. For digging, the blade is held below surface level; for transporting, it is held at the surface level; and for spreading, it is held above the surface level, as the tractor moves forward.
Bulldozers are used for shallow digging and ditching; short-range transportation of material; spreading soil dumped from trucks; rough grading; removing trees, stumps, and boulders; and cleaning and leveling around loading equipment. A bulldozer alone can do many types of excavation, and it is useful in combination with other machinery in most excavation work.
Bulldozers are useful for shallow digging and ditchdigging; short-distance transportation of material; spreading soil dumped from trucks; rough grading; removing trees, stumps, and boulders; and cleaning and leveling around loading equipment. A bulldozer alone can do many types of excavation and is useful as a helper machine on almost any job of this sort. Bulldozers can even tunnel under water.
Instead of wheels, virtually all bulldozers have tracks mounted on metal treads similar to those on a tank. These tracks use bogies (small rollers, sprockets, or wheels) mounted at the sides of the bulldozer to distribute its weight along the track. Bogies are tightly sealed to keep out dirt and rocks. Some are mounted on sealed and lubricated cylinders that move up and down, making it easier for the bulldozer to move over obstacles.
Bulldozer blades vary from about 6 to 25 feet (2 to 8 meters) in width and from about 2 to 7 feet (0.6 to 2 meters) in height. Two sets of hydraulic arms, called rams, mounted on either side of the forward portion of the engine enclosure, control the height and angle of the blade. The lower half of the blade is mounted on a frame that attaches to the bulldozer's undercarriage along each side.
The steel blade itself, reinforced at the bottom, may be straight, angled, or U-shaped, depending on its intended use. The operator sits in an open or enclosed cab at the top rear of the machine and manipulates multiple gearshifts to make the bulldozer do its work.
