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 tracks, though specialized models riding on large off-road tires are also produced. Its most popular accessory is a ripper, a large hook-like device mounted singly or in multiples in the rear to loosen dense materials.
Bulldozers are used heavily in large and small scale construction, road building,
The word "bulldozer" refers only to a motorized unit fitted with a blade designed for pushing. The word is sometimes used inaccurately for other heavy equipment such as a front-end loader designed for carrying rather than pushing material. The term originally referred only to the blade attachment but is now commonly applied to any crawler tractor with a front mounted blade.
Description
Typically, bulldozers are large and powerful
These traits allow bulldozers to excel in
A variant is the all-wheel-drive wheeled bulldozer, which generally has four large rubber-tired wheels, hydraulically operated articulated steering, and a hydraulically actuated blade mounted forward of the articulation joint.
The bulldozer's primary tools are the blade and the ripper:
Blade
Bulldozer blades come in three types:
- straight ("S blade"), short with no lateral curve or side wings. Can be used for fine grading.
- universal ("U blade"), tall and very curved, with large side wings to maximize load.
- combination ("S-U", or semi-U), shorter, with less curvature and smaller side wings. It is typically used for pushing large rocks, as at a quarry.
Blades can be fitted straight across the frame, or at an angle. All can be lifted, some, with additional hydraulic cylinders, can be tilted to vary the angle up to one side.
Sometimes, a bulldozer is used to push or pull another piece of earth-moving equipment known as a "
Dozer blades are added to
Ripper
A ripper is a long, claw-like shank that may be mounted singly or in multiples on the rear of a bulldozer to loosen hard and impacted materials. Usually a single shank is preferred for heavy ripping. The ripper is equipped with a replaceable tungsten steel alloy tip, known as a boot.
Ripping can not only loosen soil (such as podzol hardpan) in agricultural and construction applications but break shaly rock or pavement into easily handled small rubble.
A variant of the ripper is the stumpbuster,[2] a single spike protruding horizontally used to split a tree stump.
Variants
Armored bulldozers
Bulldozers employed for
Some forces' engineer doctrines differentiate between a low-mobility armoured dozer (LMAD) and a high-mobility armoured dozer (HMAD). The LMAD is dependent on a flatbed to move it to its employment site, whereas the HMAD has a more robust engine and drive system designed to give it road mobility with a moderate range and speed. HMADs, however, normally lack the full cross-country mobility characteristics of a dozer blade-equipped tank or armoured personnel carrier.
Some bulldozers have been fitted with armor by civilian operators to prevent bystanders or police from interfering with the work performed by the bulldozer, as in the case of strikes or demolition of condemned buildings. This has also been done by civilians with a dispute with the authorities, such as Marvin Heemeyer, who outfitted his Komatsu D355A bulldozer with homemade composite armor to then demolish government buildings.
Remote-controlled dozers
In recent years, innovations in the construction technology have made remote-controlled bulldozers a reality. Now, heavy machinery can be controlled from up to 1,000 feet away. This contributes to the safety of workers on the jobsite, keeping them at a secure distance from potentially dangerous jobs.
The advancement and the ability to control the heavy machinery from afar provides workers with the sufficient control over the dozers to get the job done. Though these machines are still in their early stages, many construction companies are using them successfully.[citation needed]
History
The first bulldozers were adapted from Holt farm tractors that were used to plough fields. The versatility of tractors in soft ground for logging and road building contributed to the development of the armored tank in World War I.
In 1923, farmer James Cummings and draftsman J. Earl McLeod made the first designs for the bulldozer. A replica is on display at the city park in Morrowville, Kansas, where the two built the first bulldozer.[8] On December 18, 1923, Cummings and McLeod filed U.S. patent #1,522,378 that was later issued on January 6, 1925, for an "Attachment for Tractors."[9]
By the 1920s, tracked vehicles became common, particularly the
Widespread acceptance of the bull-grader does not seem to appear before the mid-1930s. The addition of power down-force provided by hydraulic cylinders instead of just the weight of the blade made them the preferred excavation machine for large and small contractors alike by the 1940s, by which time the term "bulldozer" referred to the entire machine and not just the attachment.
Over the years, bulldozers got bigger and more powerful in response to the demand for equipment suited for ever larger
Bulldozers grew more sophisticated as time passed. Improvements include drivetrains analogous to (in automobiles) an automatic transmission instead of a manual transmission, such as the early Euclid C-6 and TC-12 or Model C Tournadozer, blade movement controlled by hydraulic cylinders or electric motors instead of early models' cable winch/brake, and automatic grade control. Hydraulic cylinders enabled the application of down force, more precise manipulation of the blade, and automated controls.
In the very snowy winter of 1946–47 in the United Kingdom, in at least one case a remote cut-off village running out of food was supplied by a bulldozer towing a big sled carrying necessary supplies.
A more recent innovation is the outfitting of bulldozers with
The best-known maker of bulldozers is Caterpillar.
Manufacturers
Industry statistics based on 2010 production published by Off-Highway Research showed Shantui was the largest producer of bulldozers, making over 10,000 units that year or two in five crawler-type dozers made in the world.[12] The next-largest producer by number of units is Caterpillar Inc., which produced 6,400 units.[12]
Komatsu introduced the D575A in 1981, the D757A-2 in 1991, and the D575A-3 in 2002, which the company touts as the biggest bulldozer in the world.[13]
History of the word
- A 19th-century term used in engineering for a horizontal forging press
- Around 1870s: In the USA, a "bulldose" was a large dose (namely, one large enough to be literally or figuratively effective against a bull) of any sort of medicine or punishment.
- By the late 1870s, "to bulldoze" and "bulldozing" were being used throughout the United States to describe intimidation "by violent and unlawful means",[14] which sometimes meant a severe whipping or coercion, or other intimidation, such as at gunpoint.[15] It had a particular meaning in the Southern United States as a whipping or other punishment for African Americans to suppress black voter turnout in the 1876 United States presidential election.[16][17][18]
- 1886: "Bulldozer" meant a large-caliber pistol and the person who wielded it.[15]
- Late 19th century: "Bulldozing" meant using brute force to push over or through any obstacle, with reference to two bulls pushing against each other's heads in a fight over dominance.[15]
- 1930s: applied to the vehicle
These appeared as early as 1929, but were known as "bull grader" blades, and the term "bulldozer blade" did not appear to come into widespread use until the mid-1930s. "Bulldozer" now refers to the whole machine, not just the attachment. In contemporary usage, "bulldozer" is sometimes shortened to "dozer", and the verb "bulldozing" to "dozing", thus making a homophone with the pre-existing verb "dozing".
Gallery
-
Caterpillar D11N with a double shank ripper
-
Bulldozer for solid waste management
-
British Challenger 2 tank fitted with dozer blade, 2020
-
Caterpillar D8 bulldozer without a cab
-
AFirst Tractor Company bulldozer still operational in 2012 on Xinbu Island, Hainan, China
-
Zettelmeyer ZD 3001 wheeled bulldozer
-
Skid-steer bulldozer
-
John Deere bulldozer
See also
- Acco super bulldozer, largest bulldozer manufactured
- Athanas for the 'bulldozer shrimp' (from the way it pushes sand about)
- Land scraper or land leveler - an earth moving machine that is pulled behind a tractor rather than pushed.
References
- ISBN 1-84084-328-4.
- ^ "The Essential Guide to Stump-Related Attachments for Heavy Machinery". www.boomandbucket.com. Retrieved 3 February 2024.
- ^ "Profile: Rachel Corrie". BBC News. 2012-08-28. Retrieved 2021-07-22.
- ^ a b c "Razing Rafah: Mass Home Demolitions in the Gaza Strip" (PDF). October 2004. Archived from the original (PDF) on 2006-03-24. Retrieved 2021-07-22.
- ^ "Israel: Caterpillar Should Suspend Bulldozer Sales". Human Rights Watch. 2004-11-21. Retrieved 2021-07-22.
- ^ "Israel's violations of human rights regarding water and sanitation in the OPT - Report by Al-Haq and EWASH to CESCR - Non-Un document". Question of Palestine. Retrieved 2021-07-22.
- ^ "Profile: Rachel Corrie". BBC News. 2012-08-28. Retrieved 2021-07-22.
- ISBN 9780762765799. Retrieved 2012-04-01.
- ^ Patent 1522378, Attachment For Tractors, John E McLeod and James D Cummings, Filed December 18, 1923.
- ^ Haddock, Keith. "Euclid-General Motors' Crawler Tractor". PEI Tractor Club. Archived from the original on 19 March 2012. Retrieved 11 September 2011.
- ^ The Kellogg Report LLC (2010). Article: The Kellogg Report. Retrieved December 15, 2010 from kelloggreport.com
- ^ a b "Shantui officially largest dozer producer in the world". The Earthmover & Civil Contractor. May 2011. Archived from the original on 2013-05-21.
- ^ "The Worlds biggest Dozer Rolls Off The Line" Archived 2015-12-30 at the Wayback Machine- Retrieved 2016-02-26
- ISBN 1346051569.
- ^ a b c "History of the Bulldozer". Archived from the original on 2023-02-21. Retrieved 2008-12-17.
- ^ Kelly, John. "What in the Word?! The racist roots of 'bulldozer'". Oxford Dictionaries. Oxford University Press. Archived from the original on 2019-03-21. Retrieved 21 October 2018.
- ^ Tréguer, Pascal (19 February 2018). "Original Meaning of 'bulldozer': A Racist Bully". Word Histories. Retrieved 13 March 2022.
The noun bulldozer is first recorded in 1876, in the plural, in the sense of Southern members or supporters of the Democratic Party who colluded to disenfranchise African-American voters; after the American Civil War (1861-65), the 15th Amendment to the Constitution, ratified on 3rd February 1870, granted Afro-American men the right to vote ... The bulldozers, also known as regulators, used threats and acts of violence in order to prevent Afro-American voters from casting their ballots for candidates of the Republican Party.
- ^ Hollandbeck, Andy (8 October 2020). "In a Word: The Racist Origins of 'Bulldozer'". Saturday Evening Post. Retrieved 13 March 2022.
External links
- The mechanism of a bulldozer Archived 2005-07-25 at the Wayback Machine (Short illustrated explanations, with flash animations, suitable for kids)
- Old engine Bulldozer pages photos
- When Bulldozers roamed the earth