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A hydraulic modular trailer (HMT) is a special platform trailer unit which feature swing axles, hydraulic suspension, independently steerable axles, two or more axle rows, compatible to join two or more units longitudinally and laterally and uses power pack unit (PPU) to steer and adjust height. [1] These trailer units are used to transport oversized load, which are difficult to disassemble and are overweight. These trailers are manufactured using high tensile steel, which makes it possible to bear the weight of the load with the help of one or more ballast tractors which push and pull these units via drawbar or gooseneck this combination of tractor and trailer is also termed as heavy hauler.
Typical loads include oil rig modules, bridge sections, buildings, ship sections, and industrial machinery such as generators and turbines also many militaries uses HMT for tank transportation. There is a limited number of manufacturers who produce these heavy-duty trailers because the market share of oversized loads is very thin when we talk about the over all transportation industry. There are self powered units of hydraulic modular trailer which are called SPMT which are used when the ballast tractors can not be applied due to space.
In 1957 the first every hydraulic modular trailers were made by Willy Scheuerle a Germany based trailer specialist which were four axles 32 wheeled modules for Robert Wynn and Sons Ltd, a Shaftesbury-based Guinness Book of Record-winning heavy haulage company. [2] Wynns were also the first to use pneumatic tires for loads weighing more than 100 tons and also to use hydraulic suspension trailers which were manufactured by Cranes Trailers limited from Dereham. [3]
In 1962 Cranes Trailers limited developed two four-axle 32-wheel modules for Pickfords a London based heavy haulage company with combined payload capacity of 160 tons on a total of eight axles and 64 wheels the modules incorporated hydraulic suspensions and each axle interlinked with mechanical steering system at an operational height varied from 2.9 to 3.11ft. The modules had drawbar coupling which could be coupled at any of both ends or even both for push-pull combination. [4]
In 1963 Goldhofer developed modular trailers in Europe for heavy haulers. [5] In the same year, Cometto developed a 300-ton capacity module in 14-axle, seven-row configuration. [6] Scheuerle also demonstrated its modules at events in 19867 [7] and later King Truck Equipment Ltd signed an agreement with Scheuerle which gave them exclusive manufacturing rights to produce their trailers in the UK. [8]
In 1971, King Truck Equipment Ltd demonstrated two units that were custom-built for Pickfords. A single unit was able to carry 150 tons on six axle rows and 48 wheels in total. Who would use them mostly with their Scammell ballast tractors via a drawbar coupling. These trailers had independent suspension and steering abilities via the Petter twin-cylinder diesel engine used as a PPU. [9]
In the 1970s, many manufacturers started to developed HMTs as the industry believed that the conventional low loaders had various limitations. To comply with new regulations and keeping safety in mind, the industry knew that they needed more axles to distribute the payload and the ultimate solution for the demand would be HMTs. Manufacturers opted hydraulic suspension instead of mechanical leaf springs and air suspension due to its efficient size and adjustable characteristics. Manufacturers chose high-tensile steel instead of aluminum because when it comes to HMTs and oversize loads, the minimizing the weight of the HMT is not relevant when they have their own payload capacity excluding the ballast tractor. The only weak point that existed on a HMT were the tires, [10] which are still a significant weakness till today, that's the reason why SPMTs have solid tires. HMTs operate at a higher speed then SPMts that's why solid tires are not an option for HMTs.
The number of axles on a HMT is not specified; two-, three-, four-, five-, six-, and eight-axle units are manufactured. Multiple units can be coupled longitudinally and laterally to transport a heavier load; each axle has a lifting capacity ranging from 18 tons to 45 tons. With a steering capacity of 50 to 60 degrees. Some combinations require a trailer operator who controls steering and height adjustments of the trailer via a controller which is modular and can be mounted at the frontend or rear end of the trailer. Huge combinations may also have a cabin for the operator, while typical combinations have a seat attached to the controller.[ citation needed ]
Hydraulic cylinders are used for steering and suspension of the trailer each axle has an individual suspension cylinder, steering rod which is connected to the main steering cylinder which is at the frontend of the trailer which makes all the axles steer at once in the same direction one row of axle consist of two turn tables, two knees, two suspension cylinders and four to eight wheels attached to a high strength metal platform. Steering and suspension cylinders are hydraulically operated using hydraulic fluid through hose pipe from the hydraulic tank, which is located near the PPU. PPU, which powers the steering, suspension to and fro flow of hydraulic fluid from hydraulic tank to suspensions and steering cylinders, puts out about 18 to 25 hp of power and are available in both diesel and petrol variants manufactured by renowned brands like Kohler, Yanmar and Hatz.[ citation needed ]
Multiple units of HMT can be interconnected longitudinally by pins and interconnecting couplings mounted in the centre of the chassis in the front and rear to interconnect them laterally they are bolted on the side wall of the chassis. HMTs can not move themselves, so There are two ways by which a HMT can be coupled with a tractor unit which can push and pull the trailer, these are gooseneck and drawbar.
[ citation needed ]
Gooseneck is the most common coupling used in the industry as the name suggest a swan shaped coupling is coupled to the trailer and the tractor via connection of trailer pin and tractor fifth wheel. This coupling can be hydraulically adjusted to suit the tractor's height also the steering controls are connected to the coupling. Goosenecks are easy to use and gives benefit to using conventional tractors, [11] but this coupling has two huge drawbacks this coupling can not be applied in a two file or side by side HMT configuration which limits the payload, and also it can not be applied in push and pull configuration. Goosenecks are manufactured by the trailers manufactures themselves. Drawbar is the most efficient and economical coupling which consists of an A-shaped frame with an I-shaped loop which is coupled to the trailer and connected to a ballast tractor via a towing hitch of the tractor. This coupling is widely used in developing countries because of its economical cost. Unlike gooseneck, this coupling can be applied to side by side and push & pull configuration [12] which, but this coupling can not be connected to a typical tractor, it requires a ballast tractor which has a ballast box instead of a fifth wheel and tow hitches in the rear and front. [13] Draw bars and tow hitches are manufacture red by companies like jost and Ringfeder.[ citation needed ]
Since 2005 in the United States of America, HMT have extra features and design changes which include widening axles, and half way folding system. Due to different road regulations in different states, almost all manufacturers have adopted the US design and developed a product for the US market. These HMT trailers are named dual lane trailers, which comes from the widening characteristic of the trailer. Dual lane trailers have capability to change its width from 13 feet (4.0 m) to 20 feet (6.1 m) wide to make transport of empty trailers easy and also comply with state regulations when required. [14]
A trailer is an unpowered vehicle towed by a powered vehicle. It is commonly used for the transport of goods and materials.
A dolly is an unpowered vehicle designed for connection to a tractor unit, truck or prime mover vehicle with strong traction power.
A tractor unit, also known as a truck unit, lorry unit, power unit, prime mover, ten-wheeler, semi-tractor, semi-truck, semi-lorry, tractor cab, truck cab, lorry cab, big rig tractor, big rig truck or big rig lorry or simply a tractor, truck, lorry, semi, big rig or rig, is a characteristically heavy-duty towing engine that provides motive power for hauling a towed or trailered load. These fall into two categories: heavy- and medium-duty military and commercial rear-wheel-drive semi-tractors used for hauling semi-trailers, and very heavy-duty typically off-road-capable, often 6×6, military and commercial tractor units, including ballast tractors.
Mammoet is a privately held Dutch company specializing in engineered heavy lifting and transport of large objects.
A semi-trailer is a trailer without a front axle. The combination of a semi-trailer and a tractor truck is called a semi-trailer truck.
Tadano Faun GmbH is a German manufacturer of mobile cranes based in the Franconian (Bavaria) town of Lauf an der Pegnitz. It is a 100% subsidiary company of the Japanese Tadano Limited. All Tadano all-terrain cranes are developed and produced in the plant in Lauf an der Pegnitz and then distributed across the globe by Tadano Faun GmbH’s global sales and service network.
Ringfeder name is a German brand based in Krefeld founded in 1922. The brand manufactures bolt couplings, hook couplings, drawbar eyes, underrun protections and accessories. Ringfeder is part of VBG Truck Equipment, one of the divisions in the VBG Group, a large international industrial group.
A heavy hauler is a very large transporter for moving oversize loads too large for road travel without an escort and special permit.
A self-propelled modular transporter or sometimes self-propelled modular trailer (SPMT) is a platform heavy hauler with a large array of wheels which is an upgraded version of a hydraulic modular trailer. SPMTs are used for transporting massive objects, such as large bridge sections, oil refining equipment, cranes, motors, spacecraft and other objects that are too big or heavy for trucks. Ballast tractors can however provide traction and braking for the SPMTs on inclines and descents.
A ballast tractor is a specially weighted tractor unit of a heavy hauler combination. It is designed to utilize a drawbar to pull or push heavy or exceptionally large trailer loads which are loaded in a hydraulic modular trailer. When feasible, lowboy-style semi-trailers are used to minimize the height of a load's center of mass. Typical drivetrains are 6×4 and 6×6, but 8×6 and 8×8 are also available. Typical ballast tractor loads include oil rig modules, bridge sections, buildings, ship sections, and industrial machinery such as generators and turbines.
A drawbar is a solid coupling between a hauling vehicle and its hauled load. Drawbars are in common use with rail transport; road trailers, both large and small, industrial and recreational; and agricultural equipment.
In transportation, heavy lift refers to the handling and installation of heavy items which are indivisible, and of weights generally accepted to be over 100 tons and of widths/heights of more than 100 meters. These oversized items are transported from one place to another, then lifted or installed into place. Characteristic for heavy-lift goods is the absence of standardization, which requires individual transport planning.
A tank transporter is a combination of a heavy tractor unit or a ballast tractor and a mating full trailer, hydraulic modular trailer or semi-trailer, used for transporting tanks and other armoured fighting vehicles. Some also function as tank recovery vehicles, the tractors of which may be armoured for protection in combat conditions.
A lowboy is a semi-trailer with two drops in deck height: one right after the gooseneck and one right before the wheels. This allows the deck to be extremely low compared with other trailers. It offers the ability to carry legal loads up to 12 ft (3.66 m) tall, which other trailers cannot. Lowboys are used to haul heavy equipment such as bulldozers and large industrial equipment.
Willème was a French truck manufacturer.
The Rotinoff Super Atlantic is a 6×4 ballast tractor made by the British company Rotinoff Motors Ltd. The tractor was designed for GCW of 200 tons with the help of a Rolls-Royce six cylinder supercharged engine producing almost 335 bhp with support of six speed main gearbox and a three speed auxiliary box for critical conditions. Kirkstall axles were used due to heavy operations of the tractor which had tire size of 18.00-25 and 14.0024 as optional to bring the vehicle to still it was equipped with compressed air brakes the drum measured 19 by 4 and 19 by 7 front and rear respectively.
MOL is a manufacturer of specialist trucks and trailers, based in Hooglede, Belgium. Specializes in manufacturing of trailers, waste vehicles, port equipement, trucks and rail equipments.
Nicolas Industrie S.A.S. is a French manufacturer of heavy trucks, trailers, HMT and SPMTs, mostly intended for oversize loads. Nicolas has been located in Champs-sur-Yonne since 1969, which is also when they started to develop vehicles meant particularly for very heavy loads. Their trucks, sold under the Tractomas brand, are built to single order. They most often incorporate Renault cabs and other parts, as well as a number of proprietary parts from manufacturers around the world. The Nicolas Tractomas TR1010 D100 currently holds the record as the world's largest road going truck, weighing in at 71 tonnes.
Faymonville Group is a trailer and heavy transport equipment manufacturer operating worldwide. Started back in the 1960s in Rocherath, Belgium as a blacksmith shop later started to manufacture and sell agriculture machines and tractor cabins in 1962 opened a new production unit to fulfill the demand of forestry vehicles. In the late 1960s, the company manufactured its first semi-trailer. Today it manufactures every type of trailer for different transportation needs, ranging from flatbeds to SPMTs. With 4 production facilities spread around Europe in Luxembourg, Belgium, Poland and Italy while having its headquarters in Luxembourg.
Nicolas Tractomas is a heavy-duty built-to-order ballast tractor specifically to tow hydraulic modular trailers and road trains used for movement of oversize loads manufactured by French manufacturer Nicolas Industrie based in Auxerre. The tractor was bespoke build with preferred engine, gearbox, drivetrain and ballast with a Renault kerax cabin. The production of the tractor began in 1979 and lasted till 2016. The TR1010 D100 model of the tractor was awarded the Guinness World Record in 2015 for the largest road truck in the world, weighing 71 tons.
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