Dump truck
A dump truck, known also as a dumping truck, dump lorry or dumper lorry or a dumper for short, is used for transporting materials for construction as well as coal. 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 on the ground behind the truck at the site of delivery. In the UK, Australia, South Africa and India the term applies to off-road construction plants only and the road vehicle is known as a tip lorry, tipper lorry, tipper truck, tip truck, tip trailer or tipper trailer or simply a tipper.
History
The dump truck is thought to have been first conceived in the farms of late 19th century western Europe. Thornycroft developed a steam dust-cart in 1896 with a tipper mechanism. The first motorized dump trucks in the United States were developed by small equipment companies such as The Fruehauf Trailer Corporation, Galion Buggy Co. and Lauth-Juergens among many others around 1910. Hydraulic dump beds were introduced by Wood Hoist Co. shortly after. Such companies flourished during World War I due to massive wartime demand. August Fruehauf had obtained military contracts for his semi-trailer, invented in 1914 and later created the partner vehicle, the semi-truck for use in World War I. After the war, Fruehauf introduced hydraulics in his trailers. They offered hydraulic lift gates, hydraulic winches and a dump trailer for sales in the early 1920s. Fruehauf became the premier supplier of dump trailers and their famed "bathtub dump" was considered to be the best by heavy haulers, road and mining construction firms.Companies like Galion Buggy Co. continued to grow after the war by manufacturing a number of express bodies and some smaller dump bodies that could be easily installed on either stock or converted Model T chassis prior to 1920. Galion and Wood Mfg. Co. built all of the dump bodies offered by Ford on their heavy-duty AA and BB chassis during the 1930s. Galion is the oldest known truck body manufacturer still in operation today.
The first known Canadian dump truck was developed in Saint John, New Brunswick, when Robert T. Mawhinney attached a dump box to a flatbed truck in 1920. The lifting device was a winch attached to a cable that fed over sheave mounted on a mast behind the cab. The cable was connected to the lower front end of the wooden dump box which was attached by a pivot at the back of the truck frame. The operator turned a crank to raise and lower the box.
From the 1930s Euclid, International-Harvester and Mack contributed to ongoing development. Mack modified its existing trucks with varying success. In 1934 Euclid became the first manufacturer in the world to successfully produce a dedicated off-highway truck.
File:Dumptruck - Kanagawa - 2024 Jan 26.webm|thumb|A dump truck with continuous track wheels crosses a river and dumps its load in Kanagawa, Japan
Types
Today, virtually all dump trucks operate by hydraulics and they come in a variety of configurations each designed to accomplish a specific task in the construction material supply chain.Standard dump truck
A standard dump truck is a truck chassis with a dump body mounted to the frame. The bed is raised by a vertical hydraulic ram mounted under the front of the body, or a horizontal hydraulic ram and lever arrangement between the frame rails, and the back of the bed is hinged at the back of the truck. The tailgate can be configured to swing up on top hinges or it can be configured in the "High Lift Tailgate" format wherein pneumatic or hydraulic rams lift the gate open and up above the dump body. Some bodies, typically for hauling grain, have swing-out doors for entering the box and a metering gate/chute in the center for a more controlled dumping.In the United States most standard dump trucks have one front steering axle and one or two rear axles which typically have dual wheels on each side. Tandem rear axles are almost always powered, front steering axles are also sometimes powered. Unpowered axles are sometimes used to support extra weight. Most unpowered rear axles can be raised off the ground to minimize wear when the truck is empty or lightly loaded, and are commonly called "lift axles".
European Union heavy trucks often have two steering axles. Dump truck configurations are two, three, and four axles. The four-axle eight wheeler has two steering axles at the front and two powered axles at the rear and is limited to gross weight in most EU countries. The largest of the standard European dump trucks is commonly called a "centipede" and has seven axles. The front axle is the steering axle, the rear two axles are powered, and the remaining four are lift axles.
The shorter wheelbase of a standard dump truck often makes it more maneuverable than the higher capacity semi-trailer dump trucks.
Semi trailer end dump truck
A semi end dump is a tractor-trailer combination wherein the trailer itself contains the hydraulic hoist. In the US a typical semi end dump has a 3-axle tractor pulling a 2-axle trailer with dual tires, in the EU trailers often have 3 axles and single tires. The key advantage of a semi end dump is a large payload. A key disadvantage is that they are very unstable when raised in the dumping position limiting their use in many applications where the dumping location is uneven or off level. Some end dumps make use of an articulated arm below the box, between the chassis rails, to stabilize the load in the raised position.Frame and Frameless end dump truck
Depending on the structure, semi trailer end dump truck can also be divided into frame trailer and frameless trailer.
The main difference between them is the different structure. The frame dump trailer has a large beam that runs along the bottom of the trailer to support it. The frameless dump trailer has no frame under the trailer but has ribs that go around the body for support and the top rail of the trailer serves as a suspension bridge for support.
The difference in structure also brings with it a difference in weight. Frame dump trailers are heavier. For the same length, a frame dump trailer weighs around 5 ton more than a frameless dump trailer.
Transfer dump truck
A transfer dump truck is a standard dump truck pulling a separate trailer with a movable cargo container, which can also be loaded with construction aggregate, gravel, sand, asphalt, klinkers, snow, wood chips, triple mix, etc.The second aggregate container on the trailer, is powered by an electric motor, a pneumatic motor or a hydraulic line. It rolls on small wheels, riding on rails from the trailer's frame into the empty main dump container. This maximizes payload capacity without sacrificing the maneuverability of the standard dump truck. Transfer dump trucks are typically seen in the western United States due to the peculiar weight restrictions on highways there.
Another configuration is called a triple transfer train, consisting of a "B" and "C" box. These are common on Nevada and Utah Highways, but not in California. Depending on the axle arrangement, a triple transfer can haul up to with a special permit in certain American states., a triple transfer costs a contractor about $105 an hour, while a A/B configuration costs about $85 per hour.
Transfer dump trucks typically haul between of aggregate per load, each truck is capable of 3–5 loads per day, generally speaking.
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.Superdump truck
A super dump is a straight dump truck equipped with a trailing axle, a liftable, load-bearing axle rated as high as. Trailing behind the rear tandem, the trailing axle stretches the outer "bridge" measurement—the distance between the first and last axles—to the maximum overall length allowed. This increases the gross weight allowed under the federal bridge formula, which sets standards for truck size and weight. Depending on the vehicle length and axle configuration, Superdumps can be rated as high as GVW and carry of payload or more. When the truck is empty or ready to offload, the trailing axle toggles up off the road surface on two hydraulic arms to clear the rear of the vehicle. Truck owners call their trailing axle-equipped trucks Superdumps because they far exceed the payload, productivity, and return on investment of a conventional dump truck. The Superdump and trailing axle concept were developed by Strong Industries of Houston, Texas.Semi trailer bottom dump truck
A semi bottom dump, bottom hopper, 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 windrow, a linear heap. In addition, a semi bottom dump is maneuverable in reverse, unlike the double and triple trailer configurations described below. These trailers may be found either of the windrow type shown in the photo or may be of the cross spread type, with the gate opening front to rear instead of left and right. The cross spread type gate will actually spread the cereal grains fairly and evenly from the width of the trailer. By comparison, the windrow-type gate leaves a pile in the middle. The cross spread type gate, on the other hand, tends to jam and may not work very well with coarse materials.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. These dump trucks allow the driver to lay material in windrows without leaving the cab or stopping the truck. The main disadvantage is the difficulty in backing double and triple units.The specific type of dump truck used in any specific country is likely to be closely keyed to the weight and axle limitations of that jurisdiction. Rock, dirt, and other types of materials commonly hauled in trucks of this type are quite heavy, and almost any style of truck can be easily overloaded. Because of that, this type of truck is frequently configured to take advantage of local weight limitations to maximize the cargo. For example, within the United States, the maximum weight limit is throughout the country, except for specific bridges with lower limits. Individual states, in some instances, are allowed to authorize trucks up to. Most states that do so require that the trucks be very long, to spread the weight over more distance. It is in this context that double and triple bottoms are found within the United States.