Kelio istorija. Kelių tiesimo metodai ir technika

Abstract

Stem was also used to power other construction equipment. The first documented application occurred in the United States in 1838 when William Otis produced a steam-powered shovel for railroad works. The next documented use was Eli Blake's jaw-type rock crusher, built in Connecticut in 1858 to produce stone for pavements. The Blake crusher could produce about 5 m' of broken stone per hour, which far exceeded the output achieved by breaking by hand. Animal power was used tor earthworks via hourse- and ox-drawn plows, scoops, scrapers, spreaders, levelling drags, and carts. In particular. earthmoving had been by hand-carried baskets panniers', wheelbarrows, and carts. The u heelbarrow was invented in China in about A. D. WO and took another millennium to reach Europe. Benjamin Colt trom California produced a usable steam-powered tractor in 1885, as a prelude to introducing the gasoline-powered crawler tractor with self-laying tracks in 1904. A tractor with a forward blade, the now famous bulldozer, was first used in 1923. Hydraulic controls for the blade were introduced in 1925.