The Caterpillar D7 is a medium bulldozer

Bulldozer

A bulldozer is a crawler equipped with a substantial metal plate used to push large quantities of soil, sand, rubble, etc., during construction work and typically equipped at the rear with a claw-like device to loosen densely-compacted materials.Bulldozers can be found on a wide range of sites,...

 manufactured by Caterpillar Inc.

Caterpillar Inc.

Caterpillar Inc. , also known as "CAT", designs, manufactures, markets and sells machinery and engines and sells financial products and insurance to customers via a worldwide dealer network. Caterpillar is the world's largest manufacturer of construction and mining equipment, diesel and natural gas...

. The first D7 appeared in 1938. The D7C came next in 1955. The D7D came in 1959. The 160hp D7E in 1961. The 180hp D7F 1969.The 200hp D7G in 1974.The 215hp in 1986.The D7H was the first D7 to come with the exclusive elevated drive sprocket undercarriage.The D7R replaced the D7H in 1996 with the current D7R Series 2 replacing that.

In March 2008, at Conexpo

CONEXPO-CON/AGG

Conexpo-Con/Agg is a trade show for the construction industry that takes place every three years. It is currently held at the Las Vegas Convention Center where the last show was held in March 2011. The next show is scheduled for March 4-8, 2014...

 2008 held every 3 years in Las Vegas, Caterpillar introduced the D7E. This 235hp D7E comes with an electric drive system powered by a 537cid C9.3 diesel engine. The C9.3 powers a generator that turns out electricity that will supply power to a pair of AC drive motors. Compared to the Caterpillar D7R Series II, the D7E is 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 240hp power and an operating weight of 25 tons, is in the middle of Caterpillar's track-type tractors, which range in size from the D3 57 kW (77 hp), 7 t (8 short tons), to the D11

Caterpillar D11

The Caterpillar D11 is a large bulldozer, manufactured by Caterpillar Inc. in East Peoria, Illinois, and mainly used in the mining industry. Primarily designed as a bulldozer, it also used for push-loading scrapers, and ripping rock overburden.-D11N:...

 698 kW (935 hp), 112 t (124 short tons). It is primarily used to move material short distances or through challenging terrain. The vehicle is powerful, yet small and light 16 to 20 t (18 to 23 short tons) 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

Tractor

A tractor is a vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction...

 without the blade

Blade

A blade is that portion of a tool, weapon, or machine with a cutting edge and/or a pointed tip that is designed to cut and/or puncture, stab, slash, chop, slice, thrust, or scrape animate or inanimate surfaces or materials...

 and ripper

Ripper

Ripper may refer to:* Jack the Ripper, a pseudonym given to an unidentified serial killer active in the largely impoverished Whitechapel area and adjacent districts of London in the latter half of 1888...

s is commonly used by farm

Farm

A farm is an area of land, or, for aquaculture, lake, river or sea, including various structures, devoted primarily to the practice of producing and managing food , fibres and, increasingly, fuel. It is the basic production facility in food production. Farms may be owned and operated by a single...

ers.

The US Army used armored D7G to clear mine fields and unarmored D7G and D7H for earthworks. The armor

Armored bulldozer

The armored bulldozer is a basic tool of combat engineering. These combat engineering vehicles combine the earth moving capabilities of the bulldozer with armor which protects the vehicle and its operator in or near combat. Most are civilian bulldozers modified by addition of vehicle armor/military...

 was developed by the Israel Military Industries

Israel Military Industries

Israel Weapons Industries , formerly the "Magen" division of the Israel Military Industries Ltd. is an Israeli firearms manufacturer. In 2005, the Small Arms Division of IMI was privatized....

 (IMI). Later, the US Army developed a remote control

Remote control

A remote control is a component of an electronics device, most commonly a television set, used for operating the television device wirelessly from a short line-of-sight distance.The remote control is usually contracted to remote...

led version of the D7G for mine

Land mine

A land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....

-clearing applications.

The United States Marine Corps

United States Marine Corps

The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...

has replaced its fleet of D7Gs with John Deere's 850J MCT in 2009

The current model is the D7R Series 2 Track-Type Tractor and will be replaced by the D7E in early 2009.

Dozer blades

The dozer blade on front of the tractor usually comes in 4 varieties:

1. A Straight Blade ("S-Blade") which is short and has no lateral curve, no side wings, and can be used for fine grading.

1. An Angle Blade: The most common type that is used on Canada and Bolivia. Angle Blade is held by an U shape frame that has 3 holes on each side, to set the blade to 3 positions: to the right, center and left.

1. A Universal Blade ("U-Blade") which is tall and very curved, and has large side wings to carry more material.

1. A "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.

External links

• Article on the Hybrid Dozer - D7E Redefines Dozer Productivity
• Caterpillar D7E Track-Type Tractor - Official Caterpillar website
• Caterpillar D-Series Track-Type Tractors - Official Caterpillar website
• olive-drab.com : Caterpillar D7 Bulldozer replaced in 2009