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An articulated hauler, articulated dump truck (ADT), or sometimes a dump hauler, is a very large heavy-duty type of
dump truck A dump truck, known also as a dumping truck, dump lorry or dumper lorry or a dumper for short, is used for transporting materials (such as dirt, gravel, or demolition waste) for construction as well as coal. A typical dump truck is equipped ...
used to transport loads over rough
terrain Terrain (), alternatively relief or topographical relief, is the dimension and shape of a given surface of land. In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientati ...
, and occasionally on public roads. The vehicle usually has
all-wheel drive An all-wheel drive vehicle (AWD vehicle) is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand. Types The most common forms of all-wheel drive are: ;1x1 : All unicycles Reflects one axle with ...
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 An off-road vehicle (ORV), also known as an off-highway vehicle (OHV), overland vehicle or adventure vehicle, is a type of transportation specifically engineered to navigate unpaved roads and surfaces. These include trails, forest roads, and ...
. Manufacturers include Volvo CE,
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 ...
,
Terex Terex Corporation is an American company and worldwide manufacturer of materials processing machinery, waste and recycling equipment, mobile elevating work platforms, and equipment for the electric utility industry. Terex does business in the ...
,
John Deere Deere & Company, Trade name, doing business as John Deere (), is an American corporation that manufactures agricultural machinery, heavy equipment, forestry machinery, diesel engines, drivetrains (axles, Transmission (mechanical device), transmi ...
/ Bell Equipment, Moxy/ Doosan, Astra and
Komatsu Limited or is a Japanese multinational corporation that manufactures construction, mining, forestry and military heavy equipment, as well as diesel engines and industrial equipment like press machines, lasers and thermoelectric generators. Its headq ...
. With half of the global sales, Volvo is the market leader in the segment, and is also the prime pioneer of the vehicle, enabling its introduction to the markets in 1966. Although first envisioned as a soil and aggregate transporter (dumper), the chassis have since been used for many other applications including agriculture, mining, construction and highway maintenance. Ranging from
concrete mixer A concrete mixer (also cement mixer) is a device that homogeneously combines cement, Construction aggregate, aggregate (e.g. sand or gravel), and water to form concrete. A typical concrete mixer uses a revolving drum to mix the components. For ...
, water tanker and container truck, over to upsize off-road
semi-trailer A semi-trailer is a trailer (vehicle), trailer without a front axle. The combination of a semi-trailer and a tractor truck is called a ''semi-trailer truck'' (also known simply as a "semi-trailer", "tractor trailer", or "semi" in the United Sta ...
hauler (on-road applications), hook loader or crane, as well as used to transport timber and as a
woodchipper A tree chipper or woodchipper is a machine used for reducing wood (generally tree limbs or trunks) into smaller woodchips. They are often portable, being mounted on wheels on frames suitable for towing behind a truck or van. Power is general ...
platform. Its chassis have also been used for military purposes given that it only is surpassed by
tracked vehicle Continuous track or tracked treads are a system of vehicle propulsion used in tracked vehicles, running on a continuous band of treads or track plates driven by two or more wheels. The large surface area of the tracks distributes the we ...
s in off-road capabilities. An example is the Archer Artillery System.


History

In 1955 the Swedish company tractor trailer manufacturer Lihnells Vagn AB (Livab) started to develop a specialized dump vehicle in cooperation with Bolinder-Munktell (BM), which in 1950 had been bought by
Volvo The Volvo Group (; 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, distribution and sale of truck ...
but still operated as an independent daughter company. This was essentially a trailer with a powered axle mated to an agricultural tractor and utilizing its
power take-off A power take-off or power takeoff (PTO) is one of several methods for taking power from a power source, such as a running engine, and power transmission#Mechanical power, transmitting it to an application such as an attached implement or separate ...
shaft to drive the trailer's axle. These were not articulated haulers in the modern sense, as the tractor retained its front axle to provide steering. As Livab's cooperation with BM deepened, it started experimenting with getting rid of the front axle by permanently attaching the trailer and instead provide steering through hydraulic cylinders forcing the trailer and wagon to turn in relation to each other. This was made in analogue with systems already developed for use in tandem tractors (see for example
Doe Triple-D The Doe Triple-D or Doe Dual Drive is a make of tractor produced by Ernest Doe & Sons in the 1950s and 1960s in Ulting Essex. Its two engines and 90-degree articulation made it one of the most unorthodox tractors ever built. Development During ...
). The first purpose-built articulated hauler was DR 631, a 4x4, released in 1966, with a larger 6x6 model DR 860 being released in 1968. In 1974 Livab was absorbed into Volvo BM. Meanwhile, a very similar vehicle was developed by another Swedish company, Kockum Landsverk AB. Having a similar tractor derived design it released its first articulated 4x4 dumper truck in 1967 named KL 411 that was replaced by a similar sized 6x6 in 1973 named KL 412. This company competed with Volvo BM until 1982 when it was bought by its bigger competitor. The early articulated haulers were rugged, lacked suspension and had manual transmissions. This made them uncomfortable, noisy and demanding to drive and contributed to operator fatigue. The lack of suspension, other than that inherent in the large tires, also put stress on the drive-train and chassis, making them unsuitable for high-speed operation and in need of frequent service. The top speed was a mere 30 km/h. Many of these concerns have been eliminated with development over the years. In 1970 a Norwegian company now known as Moxy developed its first 6x6 articulated dump truck, which was put into serial production two years later as D15. It featured a bogie undercarriage. This combination later became a de-facto industry standard. The driver situation was addressed with the introduction of front suspension in the Volvo BM 5350 of 1979. This model also saw the introduction of
automatic transmission An automatic transmission (AT) or automatic gearbox is a multi-speed transmission (mechanics), transmission used in motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions. The 1904 ...
and instead of a tractor derived cab, a new purpose designed cab. LeTourneau and Athey ADTs From NZ Contractor magazine· One of RG LeTourneau’s many design innovations was the ADT.. The first ADT, the Tournatailer, built in 1938 and was based on a Model A Tournapull, Then came the 1940 Model C Tournapull. LeTourneau Australia meanwhile built a scow-shaped dumper body for use behind the Australian Tournapull, and this was to become the Tournarocker. Following the war, LeTourneau set about designing tougher articulated rear dumpers which he christened "Tournarockers". In around 1950 the Athey company introduced their two axle AT-15 Articulated Hauler. Since then there have been developments in brakes, differentials and other aspects of the drive-train to increase speed, usability and reliability. Full suspension (meaning all three live axles now are fitted with suspension) came with the 2007 Volvo CE A35E/A40E.
Volvo trucks Volvo Trucks () is a truck manufacturing division of Volvo based in Gothenburg, Sweden. Volvo Trucks was a separate company within Volvo. The Volvo Group was reorganised on 1 January 2012 and as a part of the process, Volvo Trucks ceased to b ...
allow each of the three solid axles to move and twist independent of the other two, and therefore calls it "
independent suspension Independent suspension is any automobile suspension system that allows each wheel on the same axle to move vertically (i.e. reacting to a bump on the road) independently of the others. This is contrasted with a beam axle or deDion axle system in ...
" in their marketing materials, although it still utilizes solid axles, unlike independent suspension in automobiles. Others have since followed suit.


Design

Retained features from its agricultural
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 (vehicle), trailer or machinery such as that used in agriculture, mining or constructio ...
heritage is the operators location and the basic layout. The driver thus sit behind the engine and above the transmission and front drive axle. The permanently attached trailer can not move vertically in relation to the tractor, but can rotate and swing on the horizontal plane. The operator has a conventional steering wheel that actuates
hydraulic cylinder A hydraulic cylinder (also called a linear hydraulic motor) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment ( engineering vehicles ...
s that push and pull the tractor relative to the trailer. The tractor and the trailer sections can move at great angles to each other making for a small turning radius. The trailer axle(s) are driven by a
drive shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power (physics), power, torque, and rotation, usually ...
exiting the rear of the transmission with splines and
universal joint A universal joint (also called a universal coupling or U-joint) is a joint or coupling connecting rigid shafts whose axes are inclined to each other. It is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges ...
s to accommodate the movement between them. All axles are portals with hub reduction and
locking differential A locking differential is a mechanical component, commonly used in vehicles, designed to overcome the chief limitation of a standard open Differential (mechanical device), differential by essentially "locking" both wheels on an axle together as ...
s. Initially the axle differentials were permanently locked but recently some models can run with open but lockable differentials for better high-speed capabilities. The usual twin back axles are combined in a separate frame that can pivot in relation to the "trailer" frame, keeping all wheels on the ground, but until recently always unsprung (called a "
bogie A bogie ( ) (or truck in North American English) comprises two or more Wheelset (rail transport), wheelsets (two Railroad wheel, wheels on an axle), in a frame, attached under a vehicle by a pivot. Bogies take various forms in various modes ...
"). Likewise the less-common trucks with single rear axles usually are unsprung in the rear, while the front axle have suspension to give the operator a better ride. The reinforced cab is sometimes also sprung, as is done in modern cab-over-engine trucks, as is the drivers seat. The way the sections can twist in relation to each other and the way the vehicle steers, making the back tires follow the same path as the front tires, provide for excellent off-road capabilities in combination with all-wheel drive. The top speed is limited at 55–60 km/h (the ungoverned Archer Artillery System has a maximum road speed of "at least 70 km/h"; however this would be at expense of fuel economy and mechanical wear, and would exceed the standard speed of military convoys significantly) and the net loading capacity ranges from just below 25 to a little over 40 tonnes.


Applications

The front section of an articulated hauler can be adapted to many uses to include water tankers,


Comparison to rigid dump trucks

Articulated haulers excel in hauling material over rough terrain e.g. swamps, bogs, marshes. They are rugged and are built to handle great inclines and slippery conditions. This is their main advantage over rigid haulers, which excel in carrying capacity. Where an articulated hauler can take no more than 55 metric tonnes there are models of rigid haulers (haulers with conventional front steering and
rear-wheel drive Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars. Most rear-whee ...
) that can carry up to 310 tonnes such as the Belaz 7550.Giant Earthmovers
: An Illustrated History- p.124: Retrieved 2016-02-23
This is also seen in the way they are used. Whereas rigid haulers find their best usage at large surface mines and big quarries, where there is abundant space and hard level surfaces to drive on, articulated haulers are best used at rugged and cramped sites, such as large construction sites. The articulated haulers relatively small size also make them able to drive on public roads between different worksites at a large construction project—something that is impossible for the largest haul trucks, which might even have to be disassembled to be moved between different locations. For transportation between different construction projects, articulated haulers usually have to be hauled on flatbed trailers as oversize cargo due to their width and weight, as well as their limited speed. However, in reality, it is normal for most articulated trucks to be trailered between worksites, as there are few construction sites giving an opportunity to drive on public roads between work zones, depending on the size of the machine (chassis, wheels, etc.) and the local laws this could also be illegal. For any distance greater than a few miles, it would also be considered uneconomical wear-and-tear on the hauler trucks, to be putting hours on them that aren't contributing towards the paying job. It is far more efficient and quicker to use trucks and trailers and let them do what they specialize in, over-road hauling.


See also

*
Volvo Construction Equipment Volvo Construction Equipment - Volvo CE - (originally Munktells, Bolinder-Munktell, Volvo BM) is a major international company which develops, manufactures, and markets equipment for construction and related industries. It is a subsidiary and bu ...
*
Dump truck A dump truck, known also as a dumping truck, dump lorry or dumper lorry or a dumper for short, is used for transporting materials (such as dirt, gravel, or demolition waste) for construction as well as coal. A typical dump truck is equipped ...
* Doosan Infracore (formerly
Daewoo Daewoo ( ; ; ; ; literally "great universe" and a portmanteau of "''dae''" meaning great, and the given name of founder and chairman Kim Woo-choong) also known as the Daewoo Group, was a major South Korean chaebol (type of conglomerate) and aut ...
Heavy Industries & Machinery) - including Solar brand * Gama Goat * Archer Artillery System


References

{{reflist


External links


Information at theconstructionmachinery.com
Volvo Group Dump trucks Mining equipment nn:Dumpar#Rammestyrte dumparar