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Dump Truck Project

A short, individual project in design of how to dump stuff off a truck, due in one week.


Our company builds truck bodies for a wide range of truck sizes and chassis. The boss wants us to explore the design of a dump truck body for large trucks. Standard designs require very large forces in the hydraulic cylinder during the lifting operation. One or two 8 to 10 inch (200 to 250 mm) diameter cylinder(s) operating at 2000 psi (14 MPa) are required by our competitors. The large components are costly and the stresses produced by such large forces require reinforcing the dump body and truck chassis.

Two of the more obvious methods of reducing cylinder force are:

  • Locate the cylinder at the front of the dump body: This requires a very long stroke cylinder. We assume that this solution is not possible for us (patent infringements, space limitations, etc)
  • A cable-and-pulley system to simply double the cylinder travel for each pulley used: Half the force times twice the travel means that the hydraulic pump, lines, valves, etc must be the same size in order to raise the dump body in the same amount of time. The added complexity (see complexity analysis) is not worth the cost savings in the cylinder.

The Project

  1. Find examples of existent dumping mechanisms for large trucks on the Web. Include a properly cited image of at least one such mechanism in your report.
  2. Using simple statics and including one or more free body diagrams, calculate the magnitude of, and show where the cylinder force, is a maximum, and where it is a minimum during its travel.
  3. Conceptualize at least one mechanism to significantly reduce the required maximum cylinder force, which means trying to make the lift force more uniform over the entire cylinder stroke.
  4. A brief explanation of your concept and why you think it is a good solution. Consider factors of effectiveness, efficiency, simplicity, maintainability, safety, and cost - albeit only qualitatively. Explain any trade-offs you made.

NOTE: The cylinder and associated mechanism must be entirely under the dump body in the lowered position.


One report per student. Neat hand-drawn sketches are acceptable for your design. Sufficient information (descriptions, calculations, etc) must be presented so the reader can fully understand your thoughts. All four points above must be addressed.

An image (e.g. from the web, properly cited) of a typical dump truck mechanism in a real truck must be included in your report.

See also

mec723/dump_truck_project.txt · Last modified: 2020.03.12 13:30 (external edit)