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An articulated hauler, or sometimes a Dump Hauler, is a very large heavy duty type of dump truck used to transport loads over rough terrain. 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. Manufacturers include Caterpillar, Terex, John Deere/(Bell Equipment ), Moxy/Doosan and Volvo CE. 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. Ranging from concrete mixer, water tanker and container truck, over to up-size off-road semi-trailer hauler, hook loader or crane, as well as used to transport timber and as a woodchipper platform. Its chassis have also been used for military purposes given that it only is surpassed by tracked vehicles 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 Volvo's tractor subsidiary Volvo BM (the future Volvo CE). This was essentially a trailer with a powered axle mated to an agricultural tractor and utilizing its power take-off 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 the company's cooperation with Volvo 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 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. 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 and instead of a tractor derived cab, a new purpose designed cab. Since there have been developments in brakes, differentials and other aspects of the drive-train to increase speed, usability and reliability. Full suspension came with the 2007 Volvo CE A35E/A40E. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Articulated hauler」の詳細全文を読む スポンサード リンク
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