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A grader, also commonly referred to as a road grader, motor grader, or simply blade, is a form of heavy equipment with a long blade used to create a flat surface during grading. Although the earliest models were towed behind horses, and later tractors, most modern graders are self-propelled and thus technically "motor graders".
Typical graders have three axles, with the steering wheels in front, followed by the grading blade or mouldboard, then a cab and engine atop tandem rear axles. Some graders also have front-wheel drives for improved performance. Some graders have optional rear attachments, such as a ripper, scarifier, or compactor. 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.
In civil engineering "rough grading" is performed by heavy equipment such as wheel tractor-scrapers and bulldozers. 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 and gravel roads. In constructing paved roads, they prepare a wide flat base course for the final road surface. Graders are also used to set native soil or gravel foundation pads to finish grade before 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 is performed via a steering wheel, or a joystick 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 the articulation angle to aid in the efficiency of moving material. Other implement functions are typically hydraulically powered and can be directly controlled by levers, or by joystick inputs or electronic switches controlling electrohydraulic servo valves.
Graders are also outfitted with modern digital grade control technologies, such as those manufactured by Topcon Positioning Systems, Inc., Trimble Navigation, Leica Geosystems, or Mikrofyn. [1] These may combine both laser and GPS guidance to establish precise grade control and (potentially) "stateless" construction. Manufacturers such as John Deere have also begun to integrate these technologies during construction. [2]
Early graders were drawn by humans and draft animals. The Fresno Scraper is a machine pulled by horses used for constructing canals and ditches in sandy soil. The design of the Fresno Scraper forms the basis of most modern earthmoving scrapers, having the ability to scrape and move a quantity of soil, and also to discharge it at a controlled depth, thus quadrupling the volume which could be handled manually. The Fresno scraper was invented in 1883 by James Porteous. Working with farmers in Fresno, California, he had recognised the dependence of the Central San Joaquin Valley on irrigation, and the need for a more efficient means of constructing canals and ditches in the sandy soil. In perfecting the design of his machine, Porteous made several revisions on his own and also traded ideas with William Deidrick, Frank Dusy, and Abijah McCall, who invented and held patents on similar scrapers.[ citation needed ]
The era of motorization by traction engines, steam tractors, motor trucks, and tractors 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 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. [3]
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, Canada, and places in the United States, graders are often used in municipal and residential snow removal. In scrubland and grassland areas of Australia and Africa, graders are often an essential piece of equipment on ranches, large farms, and plantations to make dirt tracks where the absence of rocks and trees means bulldozers are not required.
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commonly, the term is used to describe a farm vehicle that provides the power and traction to mechanize agricultural tasks, especially tillage, and now many more. Agricultural implements may be towed behind or mounted on the tractor, and the tractor may also provide a source of power if the implement is mechanised.
A skid loader, skid-steer loader (SSL), or skidsteer is any of a class of compact heavy equipment with lift arms that can attach to a wide variety of buckets and other labor-saving tools or attachments.
The Caterpillar D9 is a large track-type tractor designed and manufactured by Caterpillar Inc. It is usually sold as a bulldozer equipped with a detachable large blade and a rear ripper attachment.
Excavators are heavy construction equipment primarily consisting of a boom, dipper, bucket, and cab on a rotating platform known as the "house".
A bulldozer or dozer 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.
The Fresno scraper is a machine pulled by horses used for constructing canals and ditches in sandy soil. The design of the Fresno scraper forms the basis of most modern earthmoving scrapers, having the ability to scrape and move a quantity of soil, and also to discharge it at a controlled depth, thus quadrupling the volume which could be handled manually.
James Porteous (1848–1922) was the Scottish-American inventor of the Fresno scraper.
A loader is a heavy equipment machine used in construction to move or load materials such as soil, rock, sand, demolition debris, etc. into or onto another type of machinery.
A backhoe loader, also called a loader backhoe, loader excavator, tractor excavator, digger or colloquially shortened to backhoe within the industry, is a heavy equipment vehicle that consists of a tractor-like unit fitted with a loader-style shovel/bucket on the front and a backhoe on the back. Due to its (relatively) small size and versatility, backhoe loaders are very common in urban engineering and small construction projects as well as developing countries. This type of machine is similar to and derived from what is now known as a TLB (Tractor-Loader-Backhoe), which is to say, an agricultural tractor fitted with a front loader and rear backhoe attachment.
Heavy equipment, heavy machinery, earthmovers, construction vehicles, or construction equipment, 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 equipment systems: the implement, traction, structure, power train, and control/information.
A dump truck, known also as a dumping truck, dump trailer, dumper trailer, dump lorry or dumper lorry or a dumper for short, is used for transporting materials for construction as well as coal. A typical dump truck is equipped with an open-box bed, which is hinged at the rear and equipped with hydraulic rams to lift the front, allowing the material in the bed to be deposited ("dumped") on the ground behind the truck at the site of delivery. In the UK, Australia, South Africa and India the term applies to off-road construction plants only and the road vehicle is known as a tip lorry, tipper lorry, tipper truck, tip truck, tip trailer or tipper trailer or simply a tipper.
The Caterpillar D11T is a large bulldozer introduced by Caterpillar Inc. in 1986 to replace its D10. Weighing 248,500 pounds (112,700 kg), it is Caterpillar's largest and most powerful bulldozer. Mainly used in the mining industry, it is also employed to push-load scrapers, and rip rock overburden. D11s are manufactured in East Peoria, Illinois.
The Caterpillar D6 track-type tractor is a medium bulldozer manufactured by Caterpillar Inc. with a nominal operating weight of 18 short tons (16 t). The military versions were classified as the SNL G152 medium tractor, under the G-numbers classification system used for army tractors.
In civil engineering, a wheel tractor-scraper 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 into the soil like a carpenter's plane or cheese slicer and fills the hopper which has a movable ejection system. The horsepower of the machine, depth of the cut, type of material, and slope of the cut area affect how quickly the pan is filled.
A road roller is a compactor-type engineering vehicle used to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations. Similar rollers are used also at landfills or in agriculture.
Muir Hill (Engineers) Ltd was a general engineering company based at Old Trafford, Manchester, England. It was established in the early 1920s and specialised in products to expand the use of the Fordson tractor, which in the pre-war days included sprung road wheels, bucket loaders, simple rail locomotives, and in particular in the 1930s they developed the dumper truck. Later they built high horse power tractors.
A heavy equipment operator operates heavy equipment used in engineering and construction projects. Typically only skilled workers may operate heavy equipment, and there is specialized training for learning to use heavy equipment.
The Euclid Company of Ohio was a manufacturer which specialized in heavy equipment for earthmoving, particularly dump trucks, loaders and wheel tractor-scrapers. It operated in the US from the 1920s to the 1950s, when it was purchased by General Motors. The firm was later bought by Hitachi Construction Machinery.
An articulated hauler, articulated dump truck (ADT), or sometimes a dump hauler, is a very large heavy-duty type of dump truck used to transport loads over rough terrain, and occasionally on public roads. The vehicle usually has all-wheel drive and consists of two basic units: the front section, generally called the tractor, and the rear section that contains the dump body, called the hauler or trailer section. Steering is made by pivoting the front in relation to the back by hydraulic rams. This way, all wheels follow the same path, making it an excellent off-road vehicle.
GPS when applied in the earthmoving industry can be a viable asset to contractors and increase the overall efficiency of the job. Since GPS satellite positioning information is free to the public, it allows for everyone to take advantage of its uses. Heavy equipment manufacturers, in conjunction with GPS guidance system manufacturers, have been co-developing GPS guidance systems for heavy equipment since the late 1990s. These systems allow the equipment operator to use GPS position data to make decisions based on actual grade and design features. Some heavy equipment guidance systems can even operate the machine's implements automatically from a set design that was created for the particular jobsite. GPS guidance systems can have tolerances as small as two to three centimeters making them extremely accurate compared to relying on the operator's skill level. Since the machine's GPS system has the ability to know when it is off the design grade, this can reduce surveying and material costs required for a specific job.