The Caterpillar D7 is a medium track-type tractor manufactured by Caterpillar Inc. and most commonly used as a

bulldozer A bulldozer or dozer (also called a crawler) is a large, motorized machine equipped with a metal blade to the front for pushing material: soil, sand, snow, rubble, or rock during construction work. It travels most commonly on continuous track ...

. The D7 was first manufactured in 1938. A series of improved models were later produced, including the D7C in 1955, the D7D in 1959, the D7E in 1961, the D7F in 1969 and the D7G in 1974. In 1986 the D7H was the first D7 equipped with Caterpillar’s elevated drive sprocket undercarriage. The D7R replaced the D7H in 1996, followed by the D7R Series 2. The electric drive D7E entered service in early 2009, returning to a traditional ‘flat-track’ configuration for this iteration only. The high-drive design returned in 2020 with the introduction of the D7 (forgoing a generational letter under Caterpillar’s new naming system). In March 2008, at Conexpo 2008 held every 3 years in Las Vegas, Caterpillar introduced the D7E. This D7E comes with a diesel-electric drive system powered by a 537cid C9.3 diesel engine. The C9.3 powers a generator that turns out electricity that supplies power to a pair of AC drive motors. Compared to the Caterpillar D7R Series II, the D7E was projected to deliver 25 percent more material moved per gallon of fuel, 10 percent greater productivity and 10 percent lower lifetime operating costs. The D7R Series II at power and an operating weight of around 20 tons, is in the middle of Caterpillar's track-type tractors, which range in size from the D3 , , to the D11 , . It is primarily used to move material short distances or through challenging terrain. The vehicle is powerful, yet small and light () depending on configuration). This makes it ideal for working on very steep slopes, in forests, and for backfilling pipelines safely without risking damage to the pipe. An agricultural version without the

blade A blade is the portion of a tool, weapon, or machine with an edge that is designed to puncture, chop, slice or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are to be used on. Histor ...

and rippers is commonly used by

farm A farm (also called an agricultural holding) is an area of land that is devoted primarily to agricultural processes with the primary objective of producing food and other crops; it is the basic facility in food production. The name is use ...

ers. Specially modified D7E's fitted with

Rome plows Rome plows were large, specially modified armored bulldozers used in South Vietnam by the United States military during the Vietnam War. Background The plows took their name from the city of Rome, Georgia, where they were made by the Rome Plow ...

were used to clear forest in the

Vietnam war The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...

. The

US Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

used

armored Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or f ...

D7G to clear mine fields and unarmored D7G and D7H for earthworks. The armor was developed by the

Israel Military Industries , former_name = Israel Military Industries , type = State-owned enterprise , industry = Arms industry , fate = Acquired by Elbit Systems , successor = Elbit Systems Land , founded = , founder = , defunct = , hq_location_city = Rama ...

(IMI). Later, the US Army developed a

remote control In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such ...

led version of the D7G for mine-clearing applications. The

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through c ...

replaced its fleet of D7Gs with John Deere's 850J MCT in 2009. The Egyptian Army operates an unknown number of armored D7R II.

Blades

The dozer blade on front of the tractor usually comes in 4 varieties: # Straight ("S-Blade") which is short and has no lateral curve, no side wings, and can be used for fine grading. # Angle: A type of blade, typically only 4' in height, that attaches to the dozers C-frame. The C-frame has 3 holes on each side where the blade will be manually pinned into, thus the angle blade has 3 set positions: right angle, left angle, and centered. Most commonly found in pipeline construction, due to the fact that an experienced operator can move and grade large quantities of material in a relatively short amount of time. # Universal ("U-Blade") which is tall and very curved, and has large side wings to carry more material. # "S-U" combination blade which is shorter, has less curvature, and smaller side wings. Various other blade types are used including landfill U-Blades, woodchip U-blades, and two-way blades for work inside the holds of ships. M4 Cat D7 crane

In popular culture

A WW-II era Caterpillar D7 is the main antagonist in the novella '' Killdozer!'' by Theodore Sturgeon. In the 1974 TV movie '' Killdozer!'' a D9 was used instead.

Blades

In popular culture

See also

References

External links