Crawler tractor, also known as crawler bulldozer, was successfully developed by American Benjamin Holt in 1904. It was formed by installing a manned bulldozer in front of the crawler tractor. The first source of power was the steam engine. After that, crawler bulldozers powered by natural gas and gasoline engines were successfully developed one after another, and the blades of bulldozers were also developed from artificial lift to wire rope lift.
In 1925, 5Holt Manufacturing Company merged with C.L, Best Bulldozer Company to form Caterpillar Bulldozer Company, becoming the world's first bulldozer equipment manufacturer. Benjamin Holt is also one of the founders of Caterpillar Inc.
In 1931, the first batch of 60 diesel bulldozers successfully rolled off the assembly line. With the continuous advancement of technology, all bulldozers are powered by diesel engines, and bulldozer blades and scarifiers are all lifted by hydraulic cylinders. In addition to crawler-type bulldozers, there are also tire-type bulldozers, which appeared about ten years later than crawler-type bulldozers. Because crawler bulldozers have better adhesion and can exert greater traction, the variety and quantity of their products far exceed those of tire bulldozers at home and abroad. Internationally, Caterpillar is the world's largest construction machinery manufacturing company. Crawler bulldozers include 9 series D3-D11 of large, medium and small, the largest D11 RCD, and the flywheel power of diesel engine reaches 634kw; Japan's Komatsu ranks second.
In 1947,The introduction and production of the D50 crawler bulldozer began. There are 13 series of crawler bulldozers, ranging from D21-D575, the smallest is D21, the diesel engine flywheel power is 29.5kw, the largest is D575A-3SD, the diesel engine flywheel power reaches 858kw, and it is also the largest bulldozer in the world.
In 1972, a unique bulldozer manufacturer was the German Liebheer Group. After several years of research and development, it launched a prototype and mass-produced PR721-PR731 and PR741 hydrostatic drive crawler bulldozers in 1974. All bulldozers are driven by hydrostatic pressure. . Due to the limitation of hydraulic components, the maximum power is currently only 295Kw, while the model PR751 is used for mining.
