A semi-trailer truck is the combination of a tractor unit and one or more semi-trailers to carry freight. A semi-trailer attaches to the tractor with a fifth-wheel coupling (hitch), with much of its weight borne by the tractor. The result is that both the tractor and semi-trailer will have a distinctly different design than a rigid truck and trailer.
Kingpin or king pin, originally a target in early ball games like ground billiards, has taken on a meaning of 'key component' and metaphorically of 'boss'. Today, it may refer to:
A trailer is an unpowered vehicle towed by a powered vehicle. It is commonly used for the transport of goods and materials.
A dump truck, known also as a dumper truck or tipper truck is used for transporting loose material for construction. A typical dump truck is equipped with an open-box bed, which is hinged at the rear and equipped with hydraulic rams to lift the front, allowing the material in the bed to be deposited ("dumped") on the ground behind the truck at the site of delivery. In the UK, Australia and India the term applies to off-road construction plant only, and the road vehicle is known as a tipper lorry, tip-truck, tip-trailer, tipper truck, or tipper.
A dolly is an unpowered vehicle designed for connection to a tractor unit, truck or prime mover vehicle with strong traction power.
An articulated vehicle is a vehicle which has a permanent or semi-permanent pivot joint in its construction, allowing the vehicle to turn more sharply. There are many kinds of articulated vehicles, from heavy equipment to buses, trams and trains. Steam locomotives were sometimes articulated in that the driving wheels could pivot around.
A tractor unit 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.
A semi-trailer is a trailer without a front axle. In the United States, the term is also used to refer to the combination of a truck and a semi-trailer, a tractor-trailer.
The fifth-wheel coupling provides the link between a semi-trailer and the towing truck, tractor unit, leading trailer or dolly. Some camper trailers use a fifth-wheel configuration, requiring the coupling to be installed in the bed of a pickup truck as a towing vehicle, and "fifth wheel" is therefore sometimes used as a synonym for such campers in North America. The coupling consists of a kingpin, a 2-or-3 1⁄2-inch-diameter vertical steel pin protruding from the bottom of the front of the semi-trailer, and a horseshoe-shaped coupling device called a fifth wheel on the rear of the towing vehicle.
A Toter, or Mobile Home Toter is a tractor unit specifically designed for the modular and manufactured housing industries. Some toters are highly adapted for purposes of delivering or removing mobile homes on smaller home sites. Others look and operate similar to over-the-road semi-trailer tractors with longer wheelbases and sleeper cabs.
An articulated hauler, articulated dump truck (ADT), or sometimes a dump hauler, is a very large heavy duty type of dump truck used to transport loads over rough terrain, and occasionally public roads. 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.
In the road transport or trucking industry a B-train consists of two trailers linked together by a fifth wheel, and are up to 27.5 m (92 ft) long. The fifth wheel coupling is located at the rear of the lead, or first, trailer and is mounted on a "tail" section commonly located immediately above the lead trailer axles. In North America this area of the lead trailer is often referred to as the "bridge". The twin-trailer assembly is hooked up to a tractor unit via the tractor unit's fifth wheel in the customary manner.
Truck classifications are typically based upon the maximum loaded weight of the truck (typically using the gross vehicle weight rating and sometimes also the gross trailer weight rating, and can vary among jurisdictions.
A specialized set of jargon describe the tools, equipment, and employment sectors used in the trucking industry in the United States. Some terms may be used within other English-speaking countries, or within the freight industry in general. For example, shore power is a term borrowed from shipping terminology, in which electrical power is transferred from shore to ship, instead of the ship relying upon idling its engines. Drawing power from land lines is more efficient than engine idling and eliminates localized air pollution. Another borrowed term is "landing gear", which refers to the legs which support the front end of a semi-trailer when it is not connected to a semi-truck. Some nicknames are obvious wordplay, such as "portable parking lot", in reference to a truck that carries automobiles.
In transport, D-value is a rating in kN that is typically attributed to mechanical couplings, and reflects dynamic loading limits between a towing vehicle and a trailer.
The corresponding formula for a truck and trailer combination, used to determine the required D-value of a coupling, is:
A terminal tractor, known in the United States as a shunt truck, spotter truck, spotting tractor, yard truck, yard dog, yard goat, yard horse, yard jockey or mule, is a semi-tractor intended to move semi trailers within a cargo yard, warehouse facility, or intermodal facility, much like a switcher locomotive is used to position railcars.
The Mack M123 (G792) was a 10-ton 6x6 semi-tractor introduced in 1955; the Mack M125 was a heavy cargo truck version of the M123. The M123 was used to tow tank transporter trailers while the M125 towed field artillery pieces.
The M809 Series 5-ton 6x6 truck (G908) was a family of heavy tactical trucks built for the United States Armed Forces. The basic cargo version was designed to transport a 5-ton (4,500 kg), 14 ft (4.3 m) long load over all terrain in all weather. In on-road service the load weight was doubled. Built by AM General, they evolved into the M939 Series.
