articulated lorry
A truck is a combination in road haulage .
The road train is also called articulated train or trailer train , in Switzerland trailer train .
definition
According to the definition established by law, a truck combination is a combination of a heavy goods vehicle (HGV) with a trailer , while a tractor unit with a semi-trailer is known as a truck . The definition is used in the same way in Switzerland and South Tyrol as it is in Austria. The truck is also referred to as a motor vehicle or machine vehicle in a truck trailer . In the case of a truck, the front axle of the trailer is mounted on a turntable. This means that there are at least two pivot points in a road train: the trailer coupling and the turntable. This makes it more difficult to reverse, but the truck can make tighter turns than an articulated truck.
In Germany, a road train is generally limited to a towing vehicle with a trailer. As an exception, however, up to two trailers may be carried behind pure tractors .
If the combination of a towing vehicle and two trailers is longer than the maximum permitted 18.75 m, the legislature in Germany has drawn the limit at a length of 21 m at a maximum permitted speed of 25 km / h. A tractor unit for operation with two trailers at the same time is therefore usually very short. In agriculture , the combination of a tractor with two trailers is quite common. At Showmen special permits are often issued for pulling two trailers in excess of the normally permitted train length. These trains then often have yellow beacons or all-round flashing lights on the tractor and not infrequently another one at the rear of the last trailer.
These restrictions also apply in Germany to combinations of articulated lorries and trucks ( EuroCombi ) in which a trailer is attached to an articulated vehicle. As you can see in the photo on the right, this is currently only legal in Sweden in Europe and in only 30 countries in the USA. Road trains with up to three trailers are legal in Australia, provided that it is a special roadtrain route. There are those on which only a semi-trailer and one trailer are allowed, other routes allow one semi-trailer and two trailers coupled one behind the other. Most often, such routes start about a hundred kilometers from the coast, as there is less traffic, no larger cities and wider roads. In the unpopulated Australian outback , as many trailers are usually coupled behind the first semi-trailer as the tractor can pull.
Types of road trains
- Trailer train: truck with a trailer
- EuroCombi : trucks with several trailers (steered front and / or rear axle of the trailer)
- Road Train : Truck with several trailers (unguided central axle of the trailer)
Also mentioned for the sake of completeness, but not a truck in the sense of the legal definition:
- Semi-trailer: tractor with semi-trailer (see: semi-trailer )
The trailer hitch
The trailer can either be connected to a truck with a ball coupling, a hook coupling or a so-called " jaw coupling " (a coupling with a catch). For safety reasons, open-ended couplings have become established above 7.5 t gross vehicle weight.
Hook couplings that do not close automatically have been banned in civil public road traffic in Germany and Austria since the late 1970s, as there is a risk that the trailer could separate from the towing vehicle while driving. In the civilian sector, the Americans parted ways with the hook coupling a good ten years later; it is still used in the military.
Ball head couplings are almost only found on small trailers (i.e. cars and delivery vans), as coupling is easier with them compared to a jaw coupling.
If the coupling is always on the towing vehicle, the trailer has a drawbar , the free end of which is either equipped with a half-shell for use on a ball head coupling or with a drawbar eye for use in a jaw coupling.
Advantages and disadvantages of the truck in comparison with the articulated truck
advantages
- Truck trains have a much better maneuverability than articulated trucks. In the case of narrow loading and unloading points, the load can still be moved with the solo truck. After uncoupling the semi-trailer, there is no longer any loading area on the tractor unit. In addition, you can maneuver "overhead" with the coupling at the front.
- The towing point of the trailer is on the trailer coupling at the rear of the tractor. On many tandem trailers, the coupling is often in the lower area behind the drive axle.
- Together, the loading areas can be up to 15.65 m long, which is 2.03 m longer for a truck than for a semitrailer . The loading area is interrupted roughly in the middle by the rear of the truck and the front of the trailer, but a euro truck (with an optimized loading length denomination) can load up to five euro pallets more (39) more freight than a euro trailer its 13.60 m loading area, namely 34.
- The use of swap bodies or containers with support legs for the driver to pick up and swap independently is possible.
disadvantage
- Due to the modern logistical international planning, the cargoes in the customs ports often have to be shipped by reloading. This means that full loads are loaded and unloaded faster on articulated trucks. The driver of a truck trailer must uncouple his truck (machine vehicle) from the trailer and park it separately.
- If this flexibility is to be achieved with a truck trailer, so-called swap bodies must be used, i.e. systems in which a suitably equipped truck can park its loading area without outside help and pick up another one. Compared to vehicles with fixed superstructures, swap bodies have an empty weight that is several tons higher, which reduces the payload.
- If the towing vehicle breaks down due to a technical defect, the freight in the hold cannot be transported any further. To get a swap body down from a decommissioned truck, a crane is usually needed. However, a defective tractor unit can be separated from a trailer by conventional towing .
- Road trains with central axle trailers as tandem trailers with their unguided two axles that are rigidly arranged in the middle alleviate the maneuvering problem. Maneuvering is considerably more difficult with a two-axle trailer whose front axle is steered. However, both trailer types are more manoeuvrable than a semitrailer - at least forwards.
- The total costly damage that can result from incorrectly reversing with trucks has been reason enough for many haulage companies since the 1980s to replace their trucks with articulated trucks, even though there is around 10 m³ less loading space available on a semitrailer than on one Articulated lorry.
- Even empty trucks that park a swap body and therefore no longer have any loading space, in contrast to the semitrailer tractors that go under the generic term " tractor ", are subject to the Sunday and public holiday ban that applies in some European countries. However, the legislature also provides for exceptions.
- In order to fully load or unload a load, two ramp contacts are always required, which are very time-consuming. There is an exception if there is a through-loading facility if there is a door at the front of the trailer and a bascule bridge between the units.
- Trailers often have to be parked unattended.
Individual evidence
- ↑ http://www.verkehrsportal.de/board/index.php?showtopic=90589
- ↑ Book: Commercial vehicle technology, page 105-107. Vieweg + Teubner Verlag 2008 ISBN 978-3-8348-0374-0
