All About Bulldozers
The term bulldozer may be used in a broad sense to include both a bulldozer and an angle dozer. These machines may be further divided, on the basis of their mountings, into crawler-tractor or wheel-tractor mounted. Based on the method of raising and lowering the blade, a bulldozer may be classified as cable-controlled or as hydraulically controlled. Each type of bulldozer has a place in the construction industry. For some projects either type will be satisfactory, while for other projects one type will be superior. Bulldozers are versatile machines on many construction projects, where they may be used from the start to the finish for such operations as: 1. Clearing land of timber and stumps; 2. Opening up pilot roads through mountains and rocky terrain; 3. Moving earth for haul distances up to approximately 300 feet; 4. Helping load tractor-pulled scrapers; 5. Spreading earth fill; 6. Backfilling trenches; 7. Clearing construction sites of debris; 8. Maintaining haul roads; 9. Clearing the floors of borrow and quarry pits Bulldozers are mounted with blades perpendicular to the direction of travel, while angle dozers are mounted with the blades set at an angle with the direction of travel. The former push the earth forward, while the latter push it forward and to one side. Some blades may be adjusted to permit their use as bulldozers and angle dozers. The size of a bulldozer is indicated by the length and height of the blade. Plates may be installed at the ends of a blade to reduce the spillage when a machine is used for moving earth. At one time bulldozers were mounted on crawler-tractors only. However, with the development of wheel tractors, bulldozers have been mounted on them also. Each type of mounting has advantages under certain conditions. For some jobs, the conditions are such that either type may be used satisfactorily. Under certain conditions, bulldozers are satisfactory machines for moving earth for such jobs as excavating ponds for stock water, trench silos, and highway cuts, stripping the topsoil from land or ore deposits, constructing low levees, backfilling trenches, spreading material on fills, etc. In general, haul distances should be less than 300 feet. Either a crawler-mounted or a wheel-mounted tractor may be used, a crawler-mounted machine having an advantage on short hauls with soft or muddy ground, and a wheel-mounted machine possibly having an advantage on longer hauls and firm ground. The output of a bulldozer will vary with the conditions under which it operates. During the first passes over a given lane most of the initial earth will spill off the ends of the blade to form a window on each side of the lane. After these windows have been built up to form a trench, further end spillage will be reduced or eliminated, with a substantial increase in output. |
