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the ground and gravity level has the catipillar friction

The Caterpillar D4 is a commonly used, small track-type bulldozer manufactured by its namesake, the worlds leading manufacturer of construction equipment; Caterpillar Inc.

A tractor built in 1904 by Benjamin Holt with tracks made of chain and wood slats was reported to have been observed that the tractor crawled like a caterpillar. The name stuck. Holt received the first patent for a practical continuous track for use with a tractor on December 7, 1907.

The Caterpillar Tractor Company was the result of a merger between Holt Manufacturing Co., and C.L. Best Tractor Co. Holt made a track-type tractor they called the Caterpillar, hence the name of the company.