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 (pulley) 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. 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 (known as a front post hoist configuration), or a horizontal hydraulic ram and lever arrangement between the frame rails (known as an underbody hoist configuration), and the back of the bed is hinged at the back of the truck. The tailgate (sometimes referred to as an end gate) can be configured to swing up on top hinges (and sometimes also to fold down on lower 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 (4x2 4-wheeler)) or two (6x4 6-wheeler) rear axles which typically have dual wheels on each side. Tandem rear axles are almost always powered, front steering axles are also sometimes powered (4x4, 6x6). 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