Editing Bulldozer

{{short description|Mobile machine which uses a frontal blade to push large volumes of material}}
{{redirect|Dozer}}
{{Other uses|Bulldozer (disambiguation)}}
{{More citations needed|date=May 2025}}
[[File:CatD9T.jpg|thumb|300px|A large bulldozer with multi-shank ripper, the [[Caterpillar D9]]]]

A '''bulldozer''' or '''dozer''' (also called a '''crawler''') is a large [[tractor]] equipped with a metal [[#Blade|blade]] at the front for pushing material ([[soil]], sand, snow, rubble, or rock) during [[construction]] work. It travels most commonly on [[continuous track]]s, though specialized models riding on large [[Heavy equipment#Traction: Off-the-road tires and tracks|off-road tires]] are also produced. Its most popular accessory is a [[#Ripper|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, [[mining]] and [[quarrying]], on farms, in [[heavy industry]] factories, and in military applications in both peace and wartime.

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 the generally similar [[Loader (equipment)|front-end loader]] designed for carrying material rather than pushing it. The term originally referred only to the blade attachment but is now commonly applied to any crawler tractor with a front-mounted blade.

== Description ==
{{stack|[[File:Liebherr 722 Planierraupe 1.JPG|thumb|A [[Liebherr]] bulldozer with a straight blade]]
|[[File:Liebherr 722 Planierraupe 2.JPG|thumb|The same bulldozer's multishank ripper]]}}

Typically, bulldozers are large and powerful [[tractor]]s with [[continuous track]]ed treads. The tracks give them excellent traction and mobility through very rough terrain. Wide tracks also help distribute the vehicle's weight over a large area (decreasing [[ground pressure]]), thus preventing it from sinking in [[sand]]y or [[mud]]dy ground. Extra-wide tracks are known as swamp tracks or low ground pressure (lgp) tracks. Bulldozers have [[Transmission system|transmission systems]] designed to take advantage of the track system and provide excellent [[tractive force]].

These traits allow bulldozers to excel in [[road building]], [[construction]], [[mining]], [[forestry]], [[land clearing]], infrastructure development, and any other projects requiring highly mobile, powerful, and stable earth-moving equipment.

A variant is the all-wheel-drive wheeled bulldozer, which generally has four large rubber-tired wheels, hydraulically operated [[Steering#Articulated steering|articulated steering]], and a hydraulically actuated blade mounted forward of the articulation joint.

The bulldozer's primary tools are the blade and the ripper:
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=== Blade ===
[[File:Wintershall Monte Kali 01.jpg|thumb|Bulldozer with combination blade]]
[[File:Komatsu bulldozer pushing coal in Power plant Ljubljana (winter 2017).jpg|thumb|Bulldozer pushing up to 7 m<sup>3</sup> with semi-U blade with large side wings]]

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 "[[Wheel tractor-scraper|scraper]]" to increase productivity. The towed [[Fresno Scraper]], invented in 1883 by [[James Porteous]], was the first design to enable this to be done economically, removing the soil from an area being [[cut and fill|cut]] and depositing where needed as [[cut and fill|fill]]. Dozer blades with a reinforced center section for pushing are known as "bull blades".

Dozer blades are added to [[combat engineering vehicle]]s and other military equipment, such as [[artillery tractor]]s such as the [[Hitachi Type 73|Type 73]] or [[M8 tractor]], to clear battlefield obstacles and prepare firing positions.<ref name="trewhitt">{{cite book |last=Trewhitt |first=Philip |title=Armoured Fighting Vehicles |year=1999 |publisher=Dempsey-Parr |isbn=1-84084-328-4}}</ref> Dozer blades may be mounted on [[main battle tank]]s to clear antitank obstacles or mines, and dig improvised shelters.

=== Ripper ===
[[File:Caterpillar D9N.jpg|thumb|A [[Caterpillar D9]]N equipped with a single-shank ripper]]
[[File:Liebherr 724 Planierraupe 4.jpg|thumb|Multishank 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. It is raised and lowered as desired by hydraulic cylinders. 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 rubble. 

A variant of the ripper is the stumpbuster,<ref>{{cite web |title=The Essential Guide to Stump-Related Attachments for Heavy Machinery |url=https://www.boomandbucket.com/blog/the-essential-guide-to-stump-related-attachments-for-heavy-machinery |website=www.boomandbucket.com |access-date=3 February 2024 |language=en}}</ref> a single spike protruding horizontally used to split a tree stump.
{{-}}

== Variants ==
[[File:Liebherr 631 Kettenlader 1.JPG|thumb|right|A [[tracked loader]] is designed to carry rather than push or rough-grade material]]
{{Further|topic=the small airborne bulldozer|Clark CA1}}
=== Armored bulldozers ===
{{main|Armored bulldozer}}
[[File:D9-IDF-2018-Zachi-Evenor-1.jpg|thumb|An armored [[IDF Caterpillar D9]] bulldozer used by the [[Israel Defense Forces|Israeli Military]]]]
Bulldozers employed for [[Combat engineer|combat-engineering roles]] are often fitted with [[armor]] to protect the driver from firearms and debris, enabling bulldozers to operate in combat zones. The most widely documented use is the [[Israel Defense Forces|Israeli Military]] militarized [[IDF Caterpillar D9|Caterpillar D9]], for earth moving, clearing terrain obstacles, opening routes, and detonating explosive charges. The IDF used armoured bulldozers extensively during [[2004 Israeli operation in Rafah|Operation Rainbow]] where they were used to uproot [[Gaza Strip smuggling tunnels]] and destroy residential neighbourhoods, water wells and pipes, and agricultural land<ref>{{Cite news|date=2012-08-28|title=Profile: Rachel Corrie|language=en-GB|work=BBC News|url=https://www.bbc.com/news/world-middle-east-19395651|access-date=2021-07-22}}</ref><ref name=":1">{{Cite web|date=October 2004|title=Razing Rafah: Mass Home Demolitions in the Gaza Strip|url=https://hrw.org/reports/2004/rafah1004/rafah1004text.pdf|access-date=2021-07-22|archive-url=https://web.archive.org/web/20060324184921/https://hrw.org/reports/2004/rafah1004/rafah1004text.pdf|archive-date=2006-03-24}}</ref> to expand the military [[buffer zone]] along the [[Philadelphi Route]].<ref name=":1" /> This use drew criticism against both the use and the suppliers of armoured bulldozers from human-rights organizations such as the EWASH-coalition and [[Human Rights Watch]],<ref>{{Cite web|date=2004-11-21|title=Israel: Caterpillar Should Suspend Bulldozer Sales|url=https://www.hrw.org/news/2004/11/21/israel-caterpillar-should-suspend-bulldozer-sales|access-date=2021-07-22|website=Human Rights Watch|language=en}}</ref><ref>{{Cite web|title=Israel's violations of human rights regarding water and sanitation in the OPT - Report by Al-Haq and EWASH to CESCR - Non-Un document|url=https://www.un.org/unispal/document/auto-insert-195880/|access-date=2021-07-22|website=Question of Palestine|language=en-US}}</ref> the latter of whom urged [[Caterpillar Inc.|Caterpillar]] to cease their sale of bulldozers to the IDF. The use of bulldozers was seen as necessary by Israeli authorities to uproot smuggling tunnels, destroy houses used by Palestinian gunmen, and expand the buffer zone.<ref name=":1" /><ref>{{Cite news|date=2012-08-28|title=Profile: Rachel Corrie|language=en-GB|work=BBC News|url=https://www.bbc.com/news/world-middle-east-19395651|access-date=2021-07-22}}</ref>

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 [[Strike action|strikes]] or demolition of [[Eminent domain|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|date=August 2020}}

== History ==
[[File:Cat45-mojave.jpg|thumb|alt=A train of over fifteen wagons crossing the desert, a flat sandy expanse with scrub-like bushes and a mountain range in the distance.|Two [[Holt tractor|Holt 45]] gas [[Continuous track|crawling-type]] tractors team up to pull a long wagon train in the [[Mojave Desert]] during construction of the [[Los Angeles Aqueduct]] in 1909.]]
[[File:Fiat Allis 41B Dozer.jpg|thumb|Heavy 1970s bulldozer [[Fiat Allis]] 41-B, the largest of its day]]

The first bulldozers were adapted from [[Holt Manufacturing Company|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.<ref>{{cite book|url=https://books.google.com/books?id=OZVrxulVBtoC&q=James+Cummings+J.+Earl+McLeod+bulldozer&pg=PA189 |title=Kansas Curiosities: Quirky Characters, Roadside Oddities & Other Offbeat Stuff|isbn=9780762765799|access-date=2012-04-01|last1=Grout|first1=Pam|date=15 June 2010|publisher=Rowman & Littlefield }}</ref> 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."<ref>[https://patents.google.com/patent/US1522378?oq=1522378 Patent 1522378, Attachment For Tractors, John E McLeod and James D Cummings, Filed December 18, 1923.]</ref>

By the 1920s, tracked vehicles became common, particularly the [[Caterpillar 60]]. Rubber-tired vehicles came into use in the 1940s. To dig [[canal]]s, raise earthen [[dam]]s, and do other earth-moving jobs, these tractors were equipped with a large, thick, metal plate in front. (The blade got its curved shape later). In some early models, the driver sat on top in the open without a cabin. The three main types of bulldozer blades are a U-blade for pushing and carrying soil relatively long distances, a straight blade for "knocking down" and spreading piles of soil, and a brush [[Rake (tool)|rake]] for removing brush and roots. These attachments (home-built or built by small equipment manufacturers of attachments for wheeled and crawler tractors and trucks) appeared by 1929.

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 [[earthworks (engineering)|earthworks]]. Firms such as [[Caterpillar Inc.|Caterpillar]], [[Komatsu Limited|Komatsu]], [[Clark Equipment Company|Clark Equipment Co]], [[Case CE|Case]], [[Euclid Trucks|Euclid]],<ref>{{cite web|last=Haddock|first=Keith|title=Euclid-General Motors' Crawler Tractor|url=http://pendergast.ca/antiqueengine/euclid.htm|publisher=PEI Tractor Club|access-date=11 September 2011|url-status=dead|archive-url=https://web.archive.org/web/20120319094927/http://pendergast.ca/antiqueengine/euclid.htm|archive-date=19 March 2012}}</ref> [[Allis Chalmers]], [[Liebherr]], [[LiuGong Construction Machinery, LLC.|LiuGong]], [[Terex]], [[Fiat-Allis]], [[Deere & Company|John Deere]], [[Massey Ferguson]], [[BEML]], XGMA, and [[International Harvester]] manufactured large, tracked-type earthmoving machines. [[R.G. LeTourneau]] and Caterpillar manufactured large, rubber-tired bulldozers.

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 [[Hydraulics|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.

A more recent innovation is the outfitting of bulldozers with [[GPS]] technology, such as manufactured by [[Topcon]] Positioning Systems, Inc., [[Trimble Inc]], or [[Leica Geosystems]], for precise grade control and (potentially) "stakeless" construction. As a response to the many, and often varying claims about these systems, the Kellogg Report<ref>The Kellogg Report LLC (2010). Article: The Kellogg Report. Retrieved December 15, 2010 from [https://web.archive.org/web/20110111000139/http://www.kelloggreport.com/index.html kelloggreport.com]</ref> published in 2010 a detailed comparison of all the manufacturers' systems, evaluating more than 200 features for dozers alone.

The best-known maker of bulldozers is Caterpillar. Komatsu, Liebherr, Case, [[Hitachi Construction Machinery|Hitachi]], [[Volvo Construction Equipment|Volvo]], and John Deere are present-day competitors. Although these machines began as modified farm tractors, they became the mainstay for big civil construction projects, and found their way into use by [[military]] construction units worldwide. The best-known model, the [[Caterpillar D9]], was also used to clear [[Landmines|mine]]s and [[demolition|demolish]] enemy structures.

==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 (two in five of the crawler-type dozers made worldwide).<ref name=production>{{cite news|title=Shantui officially largest dozer producer in the world |url=http://www.earthmover.com.au/new-equipment/2011/may/shantui-officially-largest-dozer-producer-in-the-world |newspaper=The Earthmover & Civil Contractor |date=May 2011 |url-status=dead |archive-url=https://web.archive.org/web/20130521222430/http://www.earthmover.com.au/new-equipment/2011/may/shantui-officially-largest-dozer-producer-in-the-world |archive-date=2013-05-21 }}</ref> The next-largest producer by number of units is Caterpillar Inc., which produced 6,400 units.<ref name=production />

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.<ref>[http://www.komatsu.com.au/AboutKomatsu/NewsAndPublications/News/Pages/THE-WORLDS-BIGGEST-DOZER-ROLLS-OFF-THE-LINE.aspx "The Worlds biggest Dozer Rolls Off The Line"] {{Webarchive|url=https://web.archive.org/web/20151230225927/http://www.komatsu.com.au/AboutKomatsu/NewsAndPublications/News/Pages/THE-WORLDS-BIGGEST-DOZER-ROLLS-OFF-THE-LINE.aspx |date=2015-12-30 }}- Retrieved 2016-02-26</ref>

==Etymology==
* A 19th-century term{{what|reason=What term - specifically?|date=March 2025}} used in engineering for a horizontal [[forging press]]{{cn|date=March 2025}}
* 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.{{cn|date=March 2025}}
*By the late 1870s, "to bulldoze"{{clarification needed|reason=How did it go from "bulldose"/"bulldosing" to "bulldoze" and "bulldozing"? A clarifying citation for this is necessary.|date=March 2025}} and "bulldozing" were being used throughout the United States to describe intimidation "by violent and unlawful means",<ref name=":0">{{Cite book|last=Bartlett|first=John Russell|title=Dictionary of Americanisms: A Glossary of Words and Phrases, Usually Regarded as Peculiar to the United States|publisher=Little, Brown, and Company|year=1877|isbn=1346051569|url=https://books.google.com/books?id=SSjVupdDGPYC|pages=76–77}}</ref> which sometimes meant a severe whipping or coercion, or other intimidation, such as at gunpoint.<ref name="History of the Bulldozer" /> 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]].<ref>{{cite web |last1=Kelly |first1=John |title=What in the Word?! The racist roots of 'bulldozer' |url=https://blog.oxforddictionaries.com/2018/02/14/word-racist-roots-bulldozer/ |website=[[Oxford English Dictionary|Oxford Dictionaries]] |publisher=[[Oxford University Press]] |access-date=21 October 2018 |url-status=dead |archive-url=https://web.archive.org/web/20190321011558/https://blog.oxforddictionaries.com/2018/02/14/word-racist-roots-bulldozer/ |archive-date=2019-03-21}}</ref><ref>{{cite web |last1=Tréguer |first1=Pascal |title=Original Meaning of 'bulldozer': A Racist Bully |url=https://wordhistories.net/2018/02/19/bulldozer-political-origin/ |website=Word Histories |date=19 February 2018 |access-date=13 March 2022 |quote=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.}}</ref><ref>{{cite web |last1=Hollandbeck |first1=Andy |title=In a Word: The Racist Origins of 'Bulldozer' |url=https://www.saturdayeveningpost.com/2020/10/in-a-word-the-racist-origins-of-bulldozer/ |website=Saturday Evening Post |access-date=13 March 2022 |date=8 October 2020}}</ref> 
* 1886: "Bulldozer" meant a large-caliber [[pistol]] and the person who wielded it.<ref name="History of the Bulldozer">{{cite web |url=http://inventors.about.com/od/bstartinventions/a/bulldozer.htm |title=History of the Bulldozer |access-date=2008-12-17 |archive-date=2023-02-21 |archive-url=https://web.archive.org/web/20230221222636/https://www.thoughtco.com/history-of-the-bulldozer-1991353 |url-status=dead }}</ref>
* 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.<ref name="History of the Bulldozer" />
* 1930s: applied to the vehicle{{cn|date=March 2025}}

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.{{cn|date=March 2025}} "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 unrelated verb "[[wikt:doze|dozing]]" (for being somnolent, napping).

== Gallery ==
<gallery mode="nolines" widths="200" heights="200">
File:Cat D11 View 2.jpg|[[Caterpillar D11]]N with a double shank ripper
File:Poti Seaport, Georgia — Receiving of New Bulldozers for Solid Waste Management (03).jpg|Bulldozer for solid waste management
File:QRH Challenger 2s in Estonia MOD 45167094.jpg|British [[Challenger 2]] tank fitted with pivoting dozer blade, 2020
File:Cabless Cat D8.jpg|[[Caterpillar D8]] bulldozer without a cab
File:First Tractor Company - old working model - 01.jpg|A [[First Tractor Company]] bulldozer still operational in 2012 on [[Xinbu Island]], Hainan, China
File:Zettelmeyer ZD 3001.jpg|Zettelmeyer ZD 3001 wheeled bulldozer
File:Skid-steer bulldozer.webp|[[Skid-steer loader|Skid-steer]] bulldozer
File:Bulldozer 2.jpg|[[John Deere]] bulldozer
</gallery>

==See also==
* [[Acco super bulldozer]], largest bulldozer manufactured
* ''[[Athanas]]'' for the 'bulldozer shrimp' (from the way it pushes sand about)
* [[Wheel tractor-scraper|Land scraper]] or land leveler - an earth moving machine that is pulled behind a tractor rather than pushed.
<!-- * [[Marvin Heemeyer]], known for his rampage with a modified bulldozer -->== References ==
{{Reflist}}

== External links ==
{{Commons category|Bulldozers}}
* [http://www.kenkenkikki.jp/special/no02/e_index.htm The mechanism of a bulldozer] {{Webarchive|url=https://web.archive.org/web/20050725081013/http://www.kenkenkikki.jp/special/no02/e_index.htm |date=2005-07-25 }} (Short illustrated explanations, with flash animations, suitable for kids)
* [https://web.archive.org/web/20080527234406/http://www.oldengine.org/members/holland/images/Australia2005/Australia2005%20440.jpg Old engine Bulldozer pages photos]
* [http://www.jlconline.com/products-tools/equipment/when-bulldozers-roamed-the-earth_o?he=9a1f48df195430f054b36c445e7e1bb5310d31ee When Bulldozers roamed the earth]

Bulldozer Working Video
* [https://www.youtube.com/@dozexearthmovers Ash dyke work and Ground leveling construction]

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[[Category:Bulldozers| ]]
[[Category:Construction equipment]]
[[Category:Demolition]]
[[Category:Engineering vehicles]]
[[Category:Heavy equipment]]
[[Category:Tracked vehicles]]
[[Category:American inventions]]