Bulldozer
Overview
 
A bulldozer is a crawler (continuous tracked tractor
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...

) equipped with a substantial metal plate (known as a blade) used to push large quantities of soil, sand, rubble, etc., during construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...

 work and typically equipped at the rear with a claw-like device (known as a ripper) to loosen densely-compacted materials.

Bulldozers can be found on a wide range of sites, mine
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

s and quarries
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...

, military bases, heavy industry factories, engineering projects and farms.

The term "bulldozer" is often used erroneously to mean any heavy equipment (sometimes a loader
Loader (equipment)
A loader is a heavy equipment machine often used in construction, primarily used to load material into or onto another type of machinery .-Heavy equipment front loaders:A loader A loader is a heavy equipment machine often used in construction, primarily used to load material (such as asphalt,...

 and sometimes an excavator
Excavator
Excavators are heavy construction equipment consisting of a boom, stick, bucket and cab on a rotating platform . The house sits atop an undercarriage with tracks or wheels. A cable-operated excavator uses winches and steel ropes to accomplish the movements. They are a natural progression from the...

), but precisely, the term refers only to a tractor (usually tracked) fitted with a dozer blade.
Encyclopedia
A bulldozer is a crawler (continuous tracked tractor
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...

) equipped with a substantial metal plate (known as a blade) used to push large quantities of soil, sand, rubble, etc., during construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...

 work and typically equipped at the rear with a claw-like device (known as a ripper) to loosen densely-compacted materials.

Bulldozers can be found on a wide range of sites, mine
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

s and quarries
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...

, military bases, heavy industry factories, engineering projects and farms.

The term "bulldozer" is often used erroneously to mean any heavy equipment (sometimes a loader
Loader (equipment)
A loader is a heavy equipment machine often used in construction, primarily used to load material into or onto another type of machinery .-Heavy equipment front loaders:A loader A loader is a heavy equipment machine often used in construction, primarily used to load material (such as asphalt,...

 and sometimes an excavator
Excavator
Excavators are heavy construction equipment consisting of a boom, stick, bucket and cab on a rotating platform . The house sits atop an undercarriage with tracks or wheels. A cable-operated excavator uses winches and steel ropes to accomplish the movements. They are a natural progression from the...

), but precisely, the term refers only to a tractor (usually tracked) fitted with a dozer blade. That is the meaning used here.

Description

Most often, bulldozers are large and powerful tracked heavy equipment. The tracks give them excellent ground hold and mobility through very rough terrain. Wide tracks help distribute the bulldozer's weight over a large area (decreasing pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

), thus preventing it from sinking in sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

y or mud
Mud
Mud is a mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone . When geological deposits of mud are formed in estuaries the resultant layers are termed bay muds...

dy ground. Extra wide tracks are known as 'swamp tracks'. Bulldozers have excellent ground hold and a torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

 divider
designed to convert the engine's power into improved dragging ability. The Caterpillar D9, for example, can easily tow tank
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...

s that weigh more than 70 tons. Because of these attributes, bulldozers are used to clear areas of obstacles, shrubbery, burnt vehicles, and remains of structures.

The bulldozer's primary tools are the blade and the ripper.

Blade

The bulldozer 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...

 is a heavy metal plate on the front of the tractor, used to push objects, and shoving sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

, soil and debris
Debris
Debris is rubble, wreckage, ruins, litter and discarded garbage/refuse/trash, scattered remains of something destroyed, or, in geology, large rock fragments left by a melting glacier etc. The singular form of debris is debris...

. Dozer blades usually come in three varieties:
  1. A straight blade ("S blade") which is short and has no lateral curve and no side wings and can be used for fine grading.
  2. A universal blade ("U blade") which is tall and very curved, and has large side wings to carry more material.
  3. An "S-U" combination blade which is shorter, has less curvature, and smaller side wings. This blade is typically used for pushing piles of large rocks, such as at a quarry.


Blades can be fitted straight across the frame, or at an angle, sometimes using additional 'tilt cylinders' to vary the angle while moving. The bottom edge of the blade can be sharpened, e.g. to cut tree stumps.

Sometimes a bulldozer is used to push another piece of earth moving equipment known as a "scraper
Wheel tractor-scraper
In civil engineering, a wheel tractor-scraper is a piece of heavy equipment used for earthmoving.The rear part has a vertically moveable hopper with a sharp horizontal front edge. The hopper can be hydraulically lowered and raised. When the hopper is lowered, the front edge cuts into the soil or...

". The towed Fresno Scraper
Fresno Scraper
The Fresno Scraper is a machine used for constructing canals and ditches in sandy soil.It was invented in 1883 by the Scottish immigrant and entrepreneur James Porteous who, having worked with farmers in Fresno, California, had recognised the dependence of the Central San Joaquin Valley on...

, invented in 1883 by James Porteous
James Porteous
James Porteous was the Scottish-American inventor of the Fresno Scraper.James Porteous was born in Haddington, East Lothian, Scotland. His father, William Porteous, had been a wheelwright and blacksmith who built and repaired carriages, wagons and farm equipment...

, was the first design to enable this to be done economically, removing the soil from the cut
Cut and fill
In earthmoving, cut and fill is the process of constructing a railway, road or canal whereby the amount of material from cuts roughly matches the amount of fill needed to make nearby embankments, so minimizing the amount of construction labor...

and depositing it elsewhere on shallow ground (fill). Many dozer blades have a reinforced center section with this purpose in mind, and are called "bull blades".

In military use, dozer blades are fixed on combat engineering vehicle
Combat engineering vehicle
Military engineering vehicles are vehicles built for the construction work or for the transportation of combat engineers on the battlefield. These vehicles can range from civilian equipment to purpose built military vehicles....

s and can optionally be fitted on other vehicles, such as artillery tractor
Artillery tractor
Artillery tractor is a kind of tractor, also referred to as a gun tractor, a vehicle used to tow artillery pieces of varying weights.-Traction:...

s such as the Type 73 or M8 Tractor
M8 Tractor
-Construction:The M8 is a full-track tractor based on the chassis of the M41 Walker Bulldog light tank. It was used to tow cargo trailers and artillery such as the Skysweeper 75 mm anti-aircraft gun and the M59 Long Tom gun. The basic M8 variant could be quickly adapted for carrying projectiles and...

. Dozer blades can also be mounted on main battle tank
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...

s, where it can be used to clear antitank obstacles, mines, and dig improvised shelters. Combat applications for dozer blades include clearing battlefield obstacles and preparing fire positions.

Ripper

The ripper is the long claw-like device on the back of the bulldozer. Rippers can come as a single (single shank/giant ripper) or in groups of two or more (multi shank rippers). Usually, a single shank is preferred for heavy ripping. The ripper shank is fitted with a replaceable tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...

 steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

 tip.

Ripping rock breaks the ground surface rock or pavement into small rubble easy to handle and transport, which can then be removed so grading can take place. With agricultural ripping, a farmer breaks up rocky or very hard earth (such as podzol hardpan) which is otherwise unploughable, in order to farm it. For example, much of the best land in the California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 wine country consists of old lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 flows. The grower shatters the lava with heavy bulldozers so surface crops or trees can be planted.

A less common rear attachment is a stumpbuster, which is a single spike that protrudes horizontally and can be raised to get it (mostly) out of the way. A stumpbuster is used to split a tree stump. A bulldozer with a stumpbuster is used for landclearing operations, and probably has a brush-rake blade.

Modifications

Bulldozers have been further modified over time to evolve into new machines which can work in ways that the original bulldozer cannot.

One example is that loader
Loader (equipment)
A loader is a heavy equipment machine often used in construction, primarily used to load material into or onto another type of machinery .-Heavy equipment front loaders:A loader A loader is a heavy equipment machine often used in construction, primarily used to load material (such as asphalt,...

 tractors were created by removing the blade and substituting a large volume bucket and hydraulic arms which can raise and lower the bucket, thus making it useful for scooping up earth and loading it into truck
Truck
A truck or lorry is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, with the smallest being mechanically similar to an automobile...

s, these are often known as a Drott.

Other modifications to the original bulldozer include making it smaller to let it operate in small work areas where movement is limited, such as in mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

. A very small bulldozer is sometimes called a calfdozer.

Some lightweight form of bulldozer are commonly used in snow removal and as a tool for preparing winter sports areas for ski and snowboard sports.

Nevertheless, the original earthmoving bulldozers are still irreplaceable as their tasks are concentrated in deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....

, earthmoving, ground levelling, and road carving. Heavy bulldozers are mainly employed to level the terrain to prepare it for construction. The construction, however, is mainly done by small bulldozers and loader
Loader (equipment)
A loader is a heavy equipment machine often used in construction, primarily used to load material into or onto another type of machinery .-Heavy equipment front loaders:A loader A loader is a heavy equipment machine often used in construction, primarily used to load material (such as asphalt,...

 tractors.

Armored bulldozers

Some bulldozers, especially bulldozers in military
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...

 usage, have been fitted with armor to protect the driver from enemy fire, enabling the bulldozer to operate in battle zones. The best-known use of an armored bulldozer
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...

 is probably the use by the Israeli Defence Forces (IDF) of the IDF Caterpillar D9
IDF Caterpillar D9
The Israeli Armored CAT D9 — nicknamed Doobi — is a Caterpillar D9 armored bulldozer that was modified by the Israel Defence Forces, Israeli Military Industries and Israel Aerospace Industries to increase the survivability of the armored bulldozer in hostile environments and enable it...

, for earth moving, clearing terrain obstacles, opening routes, detonating explosive charges and demolishing structures
House demolition in the Israeli-Palestinian conflict
House demolition is a controversial tactic used by the Israeli Defence Forces and Israeli settlers in Jerusalem, the West Bank, and the Gaza Strip against Palestinians....

 whilst under fire. The extensive use of armored bulldozers during the Second Intifada drew controversy and criticism from human rights organizations while military experts saw it as a key factor in reducing IDF casualties.

Some bulldozers have been fitted with armor by non-government civilian operators to prevent bystanders or police from interfering with the work performed by the bulldozer, as in the case of strikes
Strike action
Strike action, also called labour strike, on strike, greve , or simply strike, is a work stoppage caused by the mass refusal of employees to work. A strike usually takes place in response to employee grievances. Strikes became important during the industrial revolution, when mass labour became...

 or demolition of condemned buildings. This has also been done by civilians with a dispute with the authorities, such as Marvin Heemeyer
Marvin Heemeyer
Marvin John Heemeyer was a welder and an automobile muffler repair shop owner. Outraged over the outcome of a zoning dispute, he armored a Komatsu D355A bulldozer with layers of steel and concrete and used it on June 4, 2004, to demolish the town hall, a former judge's home, and other buildings in...

, who outfitted his Komatsu D355A bulldozer with homemade composite armor to then demolish government buildings.

History

The first bulldozers were adapted from Holt
Benjamin Holt
Benjamin Leroy Holt was an American inventor who was the first to patent and manufacture a first practical crawler-type tread tractor. The continuous-type track is used for heavy agricultural and engineering vehicles to spread the weight over a large area to prevent the vehicle from sinking into...

 farm tractors that were used to plow fields. The versatility of tractors in soft ground for logging and road building contributed to the development of the armoured tank
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...

 in World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

.

In 1923, a young farmer named James Cummings and a draftsman named J. Earl McLeod made the first designs for a bulldozer. A replica is on display at the city park in Morrowville, Kansas
Morrowville, Kansas
Morrowville is a city in Washington County, Kansas, United States. As of the 2010 census, the city population was 155.-Geography:Morrowville is located at . According to the United States Census Bureau, the city has a total area of , all of it land.-Area attractions:*...

 where the two built the first bulldozer.

By the 1920s, tracked vehicles became common, particularly the Caterpillar 60
Caterpillar 60
The Caterpillar Sixty was a crawler tractor manufactured by the Caterpillar Tractor Company from 1925 until 1931. The Sixty was the largest tractor in Caterpillar's product line at that time....

. Rubber tired vehicles came into use in the 1940s. To dig canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

s, raise earth dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

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. There are three main types of bulldozer blades: a U-blade for pushing and carrying dirt relatively long distances, a straight blade for "knocking down" and spreading piles of dirt, and a brush rake
Rake
Rake may refer to:* Rake , a horticultural implement, a long-handled tool with tines* Rake or hay rake, a farm implement* Rake or castor angle – various fork offset angles in bicycle and motorcycle geometry...

 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
Earthworks (engineering)
Earthworks are engineering works created through the moving or processing of quantities of soil or unformed rock.- Civil engineering use :Typical earthworks include roads, railway beds, causeways, dams, levees, canals, and berms...

. Firms like Caterpillar
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...

, Komatsu, Case
Case CE
Case CE, also Case Construction Equipment or simply Case, is a brand of construction equipment from CNH Global. Under this brand name, CNH Global is the fourth largest manufacturer of construction equipment behind CAT , JCB and Komatsu -History:The origins of Case can be traced back to 1842, when...

, JCB
J. C. Bamford
JCB is a global construction, demolition and agricultural equipment company headquartered in Rocester, United Kingdom. It is the world's third-largest construction equipment manufacturer. It produces over 300 types of machines, including diggers , excavators, tractors and diesel engines...

, Euclid
Euclid
Euclid , fl. 300 BC, also known as Euclid of Alexandria, was a Greek mathematician, often referred to as the "Father of Geometry". He was active in Alexandria during the reign of Ptolemy I...

 , Allis Chalmers, Liebherr
Liebherr
* The Liebherr Group, a German manufacturing complex established in 1949 by Hans Liebherr* Liebherr Grazer AK* Liebherr T 282B, an off- highway, ultra class, rigid frame, two- axle, diesel/electricappointed...

, LiuGong
LiuGong Construction Machinery, LLC.
LiuGong Construction Machinery Also known as, Guangxi LiuGong Machinery Co., Ltd. is China's largest construction equipment manufacturer and ranks 21st largest in the world. LiuGong both manufacturers and sells its construction equipment around the world...

, Terex
Terex
Terex Corporation is an American-based diversified global manufacturer of a broad range of heavy equipment for a variety of industries, including construction, infrastructure, quarrying, recycling, surface mining, shipping, transportation, refining, utility and maintenance...

, Fiat-Allis, John Deere
Deere & Company
Deere & Company, usually known by its brand name John Deere , is an American corporation based in Moline, Illinois, and the leading manufacturer of agricultural machinery in the world. In 2010, it was listed as 107th in the Fortune 500 ranking...

 and International Harvester
International Harvester
International Harvester Company was a United States agricultural machinery, construction equipment, vehicle, commercial truck, and household and commercial products manufacturer. In 1902, J.P...

 manufactured large tracked-type earthmoving machines. R.G. LeTourneau and Caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...

 manufactured large rubber tired bulldozers.

Bulldozers grew more sophisticated as time passed. Improvements include drivetrains analogous to (in automobiles) an automatic transmission
Automatic transmission
An automatic transmission is one type of motor vehicle transmission that can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears manually...

 instead of a manual transmission such as the early Euclid C-6 and TC-12 or Model C Tournadozer, blade movement controlled by hydraulic
Hydraulics
Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control,...

 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
Topcon
Topcon is a Japanese manufacturer of optical equipment for ophthalmology and surveying. Their headquarters are in Itabashi, Tokyo. They are affiliated with Toshiba, which holds 40% of Topcon's stock.-History of Topcon:...

 Positioning Systems, Inc., Trimble Inc
Trimble Inc
Trimble Navigation, Ltd. , based in Sunnyvale, California, is a provider of advanced positioning equipment, most notably GPS receivers, laser rangefinders and inertial navigation systems. The company is best known in the fields of surveying, construction, agriculture, scientific instrumentation,...

, or Leica Geosystems
Leica Geosystems
Leica Geosystems based in eastern Switzerland produces products and systems for surveying and geographical measurement...

 for precise grade control and (potentially) "stakeless" construction. As a response to the many, -and often varying claims about these systems, The Kellogg Report 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 probably Caterpillar in the USA, which earned its reputation by making tough, durable, reliable machines. Komatsu, JCB 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
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...

 construction units worldwide. The best known model, the Caterpillar D9
Caterpillar D9
Caterpillar D9 - General Characteristics Engineering Role: Heavy bulldozer Propulsion: Caterpillar tracks Engine model:CAT C18 ACERT 3408 HEUI Gross power: 464 hp D9T 474 hp D9R...

, was also used to clear mines and demolish
Demolition
Demolition is the tearing-down of buildings and other structures, the opposite of construction. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for re-use....

 enemy structures.

History of the word

  • 19th century: term used in engineering for a horizontal forging press.
  • 1886: "bulldozer" meant a large-caliber pistol
    Pistol
    When distinguished as a subset of handguns, a pistol is a handgun with a chamber that is integral with the barrel, as opposed to a revolver, wherein the chamber is separate from the barrel as a revolving cylinder. Typically, pistols have an effective range of about 100 feet.-History:The pistol...

     and the person who wielded it.
  • Around 1880: In the USA, a "bull-dose" was a large and efficient dose of any sort of medicine or punishment. 'Bull-dosing' meant a severe whip
    Whip
    A whip is a tool traditionally used by humans to exert control over animals or other people, through pain compliance or fear of pain, although in some activities whips can be used without use of pain, such as an additional pressure aid in dressage...

    ping or coercion, or other intimidation
    Intimidation
    Intimidation is intentional behavior "which would cause a person of ordinary sensibilities" fear of injury or harm. It's not necessary to prove that the behavior was so violent as to cause terror or that the victim was actually frightened.Criminal threatening is the crime of intentionally or...

     such as at gunpoint
    Gunpoint
    Gunpoint is the direction that a gun is pointing. It may also refer to:*Gunpoint , a 1966 movie Western starring Audie Murphy*"At gunpoint", under threat from a gun: see Coercion#Physical...

    .
  • Late 19th century: "bulldozing" meant using big force to push over or through any obstacle.
  • 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, and now refers to the whole machine not just the attachment. In contemporary usage, "bulldozer" is often shortened to "dozer".

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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