Articulated dump trucks (ADT) are used to move sand, soil, gravel, and rock. They are among the newest additions to the construction and mining industries, with most advancement and demands occurring within the last two decades. An articulated dump truck is also useful for dumping material into a dump; hence its name.

The ADT consists of a tractor trailer with an articulated frame and a rear component for dumping. Manufacturers typically offer 4X4, 6X6, or 6X4 drive configurations.^[1]

Contents 1 History 1.1 Early Articulated Units 1.2 ADT Design Advancements 1.3 Ground-breaking Models 1.4 Bell 1.5 Caterpillar 1.6 Volvo 1.7 Komatsu 1.8 John Deere 1.9 Moxy 2 Features/How it Works 2.1 The ADT: Inside and Out 2.2 Design and Improvements 3 Common Manufacturers 4 Additional Photos 5 References

[edit] History

[edit] Early Articulated Units

The first articulated unit can be traced back to 1940. Units were designed for pulling scrapers and were later paired to the bottom for dumping purposes. Manufacturers such as Allis-Chalmers, Caterpillar, and IH started launching versions of these hauler trailers for their scraper prime movers.

In the 1950’s, manufacturers began offering tractors with reinforced wagons attached to the rear. The trailer/tractor combination marks the early beginnings of today’s ADT.

[edit] ADT Design Advancements

Shawnee Poole, Horley, Hudson, and a Swedish company called Lihnell were among some of the companies to quickly adapt the articulated dump truck prototype, but it was Northfield, an English company, who built the first two-axle integrated hauler in 1957. The company's model could carry as much as 12.5 tons and included many of the features found in today’s ADTs, such as 180-degree articulation and hydraulic rams.^[2]

Lihnell also developed a tractor-trailer version in 1950. Its version consisted of Bolinder-Munktell farm tractor that pulled a trailer with the help of a powered axle.

A breakthrough in ADTs occurred in 1965. It was a DR630 dump truck model with a 4X4 configuration and a single axle trailer. The same year, Volvo signed an agreement with Lihnell, securing itself as the world leader in this market.

Meanwhile, a Norwegian company called Moxy introduced the first official ADT, a 6X6 truck. Moxy joined forces with Komatsu and sold its ADTs under its own name between 1986 and 2000.

In 1974, DJB Engineering of England launched its first ADT called the D250. DJB units featured the same engines and drivetrain components as Caterpillar engines.

South African Equipment company Bell Equipment launched its first line of ADTs in 1985, a 25-ton B25. This proved successful enough for the company to join with John Deer & Co. to distribute Bell ADTs under the John Deere name.

[edit] Ground-breaking Models

[edit] Bell

The Bell B30B, which was produced in 1985, was a 40-ton capacity vehicle using mass produced parts, which were easy and flexible to find. In the early 1990s, Bell produced a B20B, a 30-ton capacity machine that was given a 26 flywheel horsepower Mercedes-Benz engine. Their latest edition is the Bell B40D, a Mercedes-Benz engine with four-valve technology and electronically managed high-pressure injector, capable of carrying 40.4 tons with a 413 flywheel horsepower.^[3]

[edit] Caterpillar

The Caterpillar D550Bwas the largest ADT in the industry when it was produced in 1987.

The Caterpillar D400E ejector, produced in 1996, was the first ejector truck developed. It had a capacity for 40 tons and contained a 405 flywheel horsepower engine. It was unique for its safety in dumping, as it could dump without raising the center of gravity.

The Caterpillar 740, produced in 2001, was known for its new features: high horsepower to weight ratio, electronic transmission, and an engine compression brake that made downhill breaking much easier. The 40-ton vehicle also consisted of a radiator mounted on the back of the cab for improved visibility. An articulated dump truck is also useful for dumping material into a dump; hence it is called a dump truck.

[edit] Volvo

The Volvo A30D propelled Volvo as a leader in the ADT market. This 31-ton capability vehicle included a “load and dump” brake – a system that allowed for all brakes to be applied and neutralized through the transmission by pressing a single button.^[4]

The DR631 was the first ADT produced in mass quantities to answer demands for an all terrain hauler that could be relied upon.^[5]

[edit] Komatsu

Komatsu’s HM350-2 and HM300-2 is known for providing the highest speeds and lowest dump body.

[edit] John Deere

John Deere’s D-Series 2500 and 400D models were popular for their smooth runs and simple operation procedures.

[edit] Moxy

Moxy’s newest model has been named the largest ADT in the world, with a 51-ton capacity. This machine is popular because of the growing demands of hauling more material per trip.^[6]

[edit] Features/How it Works

[edit] The ADT: Inside and Out

The articulated frame of the ADT has made it a popular choice among contractors. It provides easy maneuverability and the front and back frames are easily separated by an oscillating hitch, a feature that keeps the wheels on the ground and minimizes stress on the truck’s frame. As well, the ADT has smaller costs contributed to construction and operation.^[7]

The cab has also undergone various improvements for maximum comfort. It is also where most of the controls are housed.

The source of the power is derived from the engine, or the powertrain, which is located beneath the cab.

The chassis allows for the payload (the materials being carried) to balance with the weight ratio. The rear is also where the hydraulics is located, a feature that allows the dump truck to be raised and lowered, and in some instances, to be released. The brakes and suspension are also located in the rear of the ADT, to be controlled by switches and levers in the cab.^[8]

[edit] Design and Improvements

Because of the simple design of the ADT, other equipment can be easily mounted on the chassis beside the rear dumping body, including:

• Water tanks
• Log and pipe carriers
• Fuel trucks
• Hydraulic booms
• Drill rigs
• Special trailers (for hauling woodchips or coals)

Other improvements include electronic controls and diagnostics, higher horsepower engines, frame design, and smoother gear selection.^[9]

Optional features include A/C, retarder, rearview camera, heated box, auto lube, ejector and tailgate.

All ADTs have an oscillation joint located between the cab and the body of the truck. This allows for the truck to move separately from the body.^[10]

The ADT is designed for maximum productivity, which makes it much more efficient than most equipment when it comes to hauling dirt, rock, and gravel. Salient to its success is the ability of the operator to choose from a 4X4 or six-wheel drive, dependent upon the conditions of the terrain. This feature makes the ADT especially efficient at working in sand or deep mud.

The articulated steering technique allows for tighter turns and better movement, a feature especially important in difficult-to-manage terrain. Operators can have better control of the machinery with the use of retardation systems (exhaust brakes, transmission retarders).

[edit] Common Manufacturers

• Bell
• Brandt
• Case
• Caterpillar
• Desmond
• Dezzi
• Haulmax
• Hitachi
• Iveco
• JCB
• John Deere
• Komatsu
• Link-Belt
• Moxy
• Terex
• Volvo
• Volvo BM

[edit] Additional Photos

[edit] References

1. ↑ Haddock, Keith. The Earthmover Encylopedia. Motorbooks: St. Paul, 2002. 157-169.
2. ↑ Haddock, Keith. The Earthmover Encylopedia. Motorbooks: St. Paul, 2002. 157-169.
3. ↑ Haddock, Keith. The Earthmover Encylopedia. Motorbooks: St. Paul, 2002. 157-169.
4. ↑ Haddock, Keith. The Earthmover Encylopedia. Motorbooks: St. Paul, 2002. 157-169.
5. ↑ Articulated Haulers. Volvo. 2008-09-24.
6. ↑ For Tricky Soils and Tough Terrain. Forester. 2008-09-24.
7. ↑ Haddock, Keith. The Earthmover Encylopedia. Motorbooks: St. Paul, 2002. 157-169.
8. ↑ ADTs. Deere. 2008-09-24.
9. ↑ Haddock, Keith. The Earthmover Encylopedia. Motorbooks: St. Paul, 2002. 157-169.
10. ↑ Supplier Newsline. Forestnet. 2008-09-24.