Dump truck
From Wikipedia, the free encyclopedia
A dump truck or production truck is a truck used for transporting loose material (such as sand, gravel, or dirt) for construction. A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear, the front of which can be lifted up to allow the contents to be deposited on the ground behind the truck at the site of delivery. In the UK the term applies to off-road construction plant only, the road vehicle is known as a tipper.
[edit] Types of dump trucks
Dump trucks come in a variety of configurations each specified to accomplish a specific task in the construction material supply chain.
[edit] Standard dump truck
A standard dump truck is a full truck chassis with a dump body mounted to the frame. The dump body is raised by a hydraulic ram mounted forward of the front bulkhead, between the truck cab (traction unit) and the dump body (semi-trailer). The tailgate can be configured to swing on hinges or it can be configured in the "High Lift Tailgate" format wherein pneumatic rams lift the gate open and up above the dump body.
A standard dump truck has one front axle, and one or more rear axles which typically have dual wheels on each side. Common configurations for a standard dump truck include the six wheeler which has one rear axle, the ten wheeler with two rear axles, and the tri-axle with three rear axles. These are mainly found in inner cities and in the deep south.
The short wheelbase of a standard dump truck makes it more maneuverable than the higher capacity semi-trailer dump trucks.
[edit] Articulated dump truck
An articulated dump truck has a hinge between the cab and the dump box, but is distinct from semi trailer trucks in that the cab is a permanent fixture, not a separable vehicle. Steering is accomplished via hydraulic rams that pivot the entire cab, rather than rack and pinion steering on the front axle. This vehicle is highly adaptable to rough terrain. In line with its use in rough terrain longer distances and overly flat surfaces tend to cause driveline troubles, and failures. Articulated trucks are often referred to as the modern scraper, in the sense that they carry a much higher maintenance burden than most trucks.
[edit] Transfer dump truck
 Example of a transfer truck and trailer |
A transfer dump (colloquially referred to as a "Slam-Bang!" because of the noise made when transferring) is a standard dump truck which pulls a separate trailer which can also be loaded with aggregate (gravel, sand, asphalt, etc.)
The second aggregate container, (B box) on the trailer which is powered by either an electric or pneumatic motor, rides on small wheels and rolls on rails off of the trailer frame and into the empty main dump (A) box. The key advantage of this configuration is to maximize payload capacity without sacrificing the maneuverability of the short and nimble standard dump truck. Transfer dumps are typically seen in the western United States because of the peculiar weight restrictions on western highways.
[edit] Truck and pup
A truck and pup is very similar to a transfer dump. It consists of a standard dump truck pulling a dump trailer. The pup trailer, unlike the transfer, has its own hydraulic ram and is capable of self-unloading.
[edit] Super dump truck
A super dump is similar to a standard dump truck except it is equipped with trailing axles or sting axle to maximize the payload .
[edit] Semi trailer end dump truck
A semi end dump is a tractor-trailer combination wherein the trailer itself contains the hydraulic hoist. A typical semi end dump has a 3-axle tractor pulling a 2-axle semi-trailer. The key advantage of a semi end dump is rapid unloading.
[edit] Semi trailer bottom dump truck
A semi bottom dump (or "belly dump") is a 3-axle tractor pulling a 2-axle trailer with a clam shell type dump gate in the belly of the trailer. The key advantage of a semi bottom dump is its ability to lay material in a wind row. In addition, a semi bottom dump is maneuverable in reverse, unlike the double and triple trailer configurations described below.
[edit] Double and triple trailer bottom dump truck
Double and triple bottom dumps consist of a 2-axle tractor pulling one single-axle semi-trailer and an additional full trailer (or two full trailers in the case of triples). These dump trucks allow the driver to lay material in wind rows without ever leaving the cab or even stopping the truck. The main disadvantage is the difficulty in backing double and triple units in reverse.
[edit] Side dump truck
A side dump truck consists of a 3-axle tractor pulling a 2-axle semi-trailer. It has hydraulic rams which tilt the dump body onto its side, spilling the material to either the left or right side of the trailer. The key advantages of the side dump are that it allows rapid unloading and can carry more weight in western United States. In addition, it is almost immune to upset (tipping over) while dumping unlike the semi end dumps which are very prone to tipping over. It is, however, highly likely that a side dump trailer will tip over if dumping is stopped prematurely. A disadvantage occurs when dumping lose materials or cobble sized stone, the side dump will often get stuck in its own pile.
[edit] Off-road dump truck
Off-road dump trucks more closely resemble heavy construction equipment or engineering vehicles than they do highway dump trucks. They are used strictly off-road for mining and heavy dirt hauling jobs.
The term ‘Dump’ Truck is not generally used by the mining industry, or by the manufacturers that build these machines. The more appropriate US term for this strictly off road vehicle is, ‘Haul’ truck. The classification bottom and side for example, describes how the loaded material is discharged once loaded. In the case of the Haul truck illustrated, a Liebherr T 282B the load is discharged to the rear, designating this particular vehicle as an end dump. Bottom dump normally describes a trailer that discharges its load by opening two cam shell doors under the load space, in some examples several trailers (road train) are pulled by one truck mainly these are on road machines. The only remaining example of what is described as a unitized bottom dump coal hauler is manufactured by Kress Corporation. This large capacity truck is used for the transportation of coal from a loading device (shovel) directly to a power station or bulk storage area.
[edit] Winter service vehicles
Many winter service vehicle units are based on dump trucks, to allow the placement of ballast to weigh the truck down or to hold salt for spreading on the road.
[edit] Dangers
Potentially flying goods must be covered (i.e. using a canvas, straps or a rope) to prevent loose material from flying outside the bed when the truck is moving, and to keep the goods from damaging other vehicles. Also heavier items loaded over the edge of the truck must be secured to prevent them from dropping off the truck in turns, on bad roads or when braking the vehicle.
Trucks are normally built for some amount of off road driving or construction site driving, which means that bumpers are either placed high or not even there because the chassis and height of the drivers seat protects the driver fairly. The disadvantage is that in a collision with a family car, the entire motor section or luggage compartment goes under the truck bumper ant only the roof and window section makes mentionable contact to the truck. This means that passengers in the car could be cut off at chest height instead of having minor damage in the lower leg region which would be the part the car is protecting through its design. Several countries have made rules that new trucks should have bumpers approximately 40 cm above ground in order to protect other drivers better. Also there are rules about how long the load or construction of the truck can go beyond the rear bumper. This to prevent that cars rear-ending the truck will be cut off. Several pictures on the internet show the last case, in example a Corvette sticking out 50 cm from the edge of a semi trailer [1].
[edit] See also
- BelAZ
- Caterpillar Inc.
- Dumper
- Euclid Trucks
- Liebherr
- Komatsu
- List of dump truck manufacturers
- International
- Peterbilt
- Semi-trailer and semi-trailer truck
- Tractor unit
- Train
- Waste collection vehicle
- Hitachi Construction Machinery (Europe)
- Terex Corporation
[edit] External links and references
- VRML Simulation of an Excavator, Tower Crane, and Dumptruck
- Side Dump Industries Manufacturer of side dump semitrailers
- Tisvol Manufacturer of end dump semitrailers
- Vortex Truck and Equipment Manufacturer of grapple dump trucks
