A grader, also commonly referred to as a road grader, motor grader, or simply a blade, is a form of

heavy equipment Heavy equipment or heavy machinery refers to heavy-duty vehicles specially designed to execute construction tasks, most frequently involving earthwork operations or other large construction tasks. ''Heavy equipment'' usually comprises five e ...

with a long blade used to create a flat surface during grading. Although the earliest models were towed behind horses, and later

tractor A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commo ...

s, most modern graders are self-propelled and thus technically "motor graders". Typical graders have three

axle An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, beari ...

s, with the steering wheels in front, followed by the grading

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 ...

, then a cab and

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ...

atop

tandem Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction. The original use of the term in English was in ''tandem harness'', which is used for two ...

rear axles. Some graders also have front wheel drive for improved performance. Some graders have optional rear attachments, such as a ripper,

scarifier A dethatcher or lawn scarifier is a device that removes thatch from lawns. Types of dethatchers include motorized dethatchers or those that can be pulled behind a garden tractor. Thatch removal (dethatching) Scarification or de-thatching of ...

, or

compactor A compactor is a machine or mechanism used to reduce the size of material such as waste material or bio mass through compaction. A trash compactor is often used by a home or business to reduce the volume of trash it produces. A baler-wrapper comp ...

. A blade forward of the front axle may also be added. For snowplowing and some dirt grading operations, a main blade extension can also be mounted. Capacities range from a blade width of 2.50 to 7.30 m (8 to 24 ft) and engines from 93–373 kW (125–500 hp). Certain graders can operate multiple attachments, or be designed for specialized tasks like underground mining.

Function

civil engineering Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewa ...

"rough grading" is performed by heavy equipment such as

wheel tractor-scraper In civil engineering, a wheel tractor-scraper (also known as a Tournapull) is a type of heavy equipment used for earthmoving. It has a pan/hopper for loading and carrying material. The pan has a tapered horizontal front cutting edge that cuts in ...

s and

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 ...

s. Graders are used to "finish grade", with the angle, tilt (or pitch) and height of their blade capable of being adjusted to a high level of precision. Graders are commonly used in the construction and maintenance of

dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debris: scattered pieces of waste or remains * Dust: a gener ...

and

gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...

roads. In constructing paved roads, they prepare a wide flat

base course The base course or basecourse in pavements is a layer of material in an asphalt roadway, race track, riding arena, or sporting field. It is located under the surface layer consisting of the ''wearing course'' and sometimes an extra ''binder cour ...

for the final

road surface A road surface (British English), or pavement (American English), is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, hoggin, cob ...

. Graders are also used to set native

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

foundation Foundation may refer to: * Foundation (nonprofit), a type of charitable organization ** Foundation (United States law), a type of charitable organization in the U.S. ** Private foundation, a charitable organization that, while serving a good cause ...

pads to finish grade prior to the construction of large buildings. Graders can produce canted surfaces for drainage or safety. They may be used to produce drainage ditches with shallow V-shaped cross-sections on either side of highways.

Steering Steering is a system of components, linkages, and other parts that allows a driver to control the direction of the vehicle. Introduction The most conventional steering arrangement allows a driver to turn the front wheels of a vehicle using ...

is performed via a

steering wheel A steering wheel (also called a driving wheel (UK), a hand wheel, or simply wheel) is a type of steering control in vehicles. Steering wheels are used in most modern land vehicles, including all mass-production automobiles, buses, light an ...

, or a

joystick A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...

capable of controlling both the angle and cant of the front wheels. Many models also allow frame articulation between the front and rear axles, which allows a smaller turning radius in addition to allowing the operator to adjust articulation angle to aid in the efficiency of moving material. Other implement functions are typically hydraulically powered, and can be directly controlled by

lever A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or '' fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is d ...

s, or by joystick inputs or electronic switches controlling

electrohydraulic servo valve An electrohydraulic servo valve (EHSV) is an electrically-operated valve that controls how hydraulic fluid is sent to an actuator.https://www.moog.com/literature/ICD/Valves-Introduction.pdf Servo valves are often used to control powerful hydrauli ...

s. Graders are also outfitted with modern digital grade control technologies, such as those manufactured by Topcon Positioning Systems, Inc.,

Trimble Navigation Trimble Inc. is an American software, hardware, and services technology company. Trimble supports global industries in building & construction, agriculture, geospatial, natural resources and utilities, governments, transportation and others. Trim ...

Leica Geosystems Leica Geosystems (formerly known as Wild Heerbrugg or just Wild) based in eastern Switzerland produces products and systems for surveying and geographical measurement (geomatics). Its products employ a variety of technologies including GPS sa ...

or Mikrofyn. These may combine both

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The ...

and

GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...

guidance to extablish precise grade control and (potentially) "stakeless" construction. Manufacturers such as

John Deere Deere & Company, doing business as John Deere (), is an American corporation that manufactures agricultural machinery, heavy equipment, forestry machinery, diesel engines, drivetrains (axles, transmissions, gearboxes) used in heavy equipment, ...

have also began to integrate these technologies during construction.

History

Early graders were drawn by humans and draft animals. The era of motorization by

traction engine A traction engine is a steam engine, steam-powered tractor used to move heavy loads on roads, plough ground or to provide power at a chosen location. The name derives from the Latin ''tractus'', meaning 'drawn', since the prime function of any t ...

steam tractor :''This article refers to the steam-powered agricultural tractor; for other types of steam tractor, see: Traction engine'' A steam tractor is a vehicle powered by a steam engine which is used for pulling. In North America, the term ''steam ...

s, motor trucks, and

s saw such towed graders grow in size and productivity. The first self-propelled grader was made in 1920 by the Russell Grader Manufacturing Company, which called it the Russell Motor Hi-Way Patrol. These early graders were created by adding the grader blade as an attachment to a generalist tractor unit. After purchasing the company in 1928,

Caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sy ...

went on to truly integrate the tractor and grader into one design—at the same time replacing crawler tracks with wheels to yield the first rubber-tire self-propelled grader, the Caterpillar Auto Patrol, released in 1931.

Regional uses

In addition to their use in road construction, graders may also be used to perform roughly equivalent work. In some locales such as

Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe Northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54°N, or may be based on other geographical factors ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

, and places in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, graders are often used in municipal and residential

snow removal Snow removal or snow clearing is the job of removing snow after a snowfall to make travel easier and safer. This is done by both individual households and by governments and institutions. De-icing and anti-icing De-icing is defined as removal ...

. In scrubland and grassland areas of

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, graders are often an essential piece of equipment on

ranch A ranch (from es, rancho/Mexican Spanish) is an area of land, including various structures, given primarily to ranching, the practice of raising grazing livestock such as cattle and sheep. It is a subtype of a farm. These terms are most ofte ...

es, large

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 ...

s, and

plantation A plantation is an agricultural estate, generally centered on a plantation house, meant for farming that specializes in cash crops, usually mainly planted with a single crop, with perhaps ancillary areas for vegetables for eating and so on. Th ...

s to make dirt tracks where the absence of rocks and trees means bulldozers are not required. Descosweep

Manufacturers

* Case CE *

Caterpillar Inc. Caterpillar Inc. (stock symbol CAT) is an American ''Fortune'' 500 corporation and the world's largest construction-equipment manufacturer. In 2018, Caterpillar was ranked number 65 on the ''Fortune'' 500 list and number 238 on the Global ''Fo ...

Deere & Company Deere & Company, doing business as John Deere (), is an American corporation that manufactures agricultural machinery, heavy equipment, forestry machinery, diesel engines, drivetrains (axles, transmissions, gearboxes) used in heavy equipmen ...

Galion Iron Works Galion Iron Works is the original name of the company that built the ''Galion'' brand of construction equipment. Known for their graders, it also manufactured rollers, cranes, asphalt millers and even riding squeegees among other machines. Gal ...

* HEPCO *

Komatsu Limited or () is a Japanese multinational corporation that manufactures construction, mining, forestry and military equipment, as well as diesel engines and industrial equipment like press machines, lasers and thermoelectric generators. Its headquart ...

LiuGong Construction Machinery, LLC. LiuGong, officially Guangxi LiuGong Machinery Co., Ltd., is a Chinese multinational construction machinery manufacturing company headquartered in Liuzhou, China. It is the world's 10th-largest construction equipment manufacturer by market share ...

Mitsubishi Heavy Industries is a Japanese multinational engineering, electrical equipment and electronics corporation headquartered in Tokyo, Japan. MHI is one of the core companies of the Mitsubishi Group and its automobile division is the predecessor of Mitsubishi ...

New Holland Construction New Holland Construction is an American manufacturer of construction machinery. Along with New Holland Agriculture, New Holland Construction is a brand of CNH. New Holland Construction produces construction equipment including backhoes, excav ...

* Sany *

Terex Corporation Terex Corporation is an American worldwide manufacturer of lifting and material-handling plant for a variety of industries including construction, infrastructure, quarrying, recycling, energy, mining, shipping, transportation, refining and ut ...

Volvo The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...

SDLG Shandong Lingong Construction Machinery Co., Ltd. (abbreviated SDLG), founded in 1972, is a subsidiary corporation of Volvo Construction Equipment, headquartered in Linyi, Shandong. Shandong Lingong Construction Machinery Co. is one of the most ...

XCMG Xuzhou Construction Machinery Group Co., Ltd. (XCMG Group) ( zh, s=徐工集团, p=Xúgōng Jítuán) is a Chinese multinational state-owned heavy machinery manufacturing company with headquarters in Xuzhou, Jiangsu. Founded in 1989, XCMG ...

References

External links

Video with technical development from gradersphotos/videos from different type of grader works
*''A Road-Scraper That Cuts Through Snow'',

Popular Science ''Popular Science'' (also known as ''PopSci'') is an American digital magazine carrying popular science content, which refers to articles for the general reader on science and technology subjects. ''Popular Science'' has won over 58 awards, incl ...