Commercial dump trucks have become one of the great contributors to the construction industry since it was first envisioned in the early part of the 20th century. It has certainly evolved from the original design of a cable and pulley system to the hydraulically operated modern dump trucks of today

It is certainly amazing to the average viewer of this vehicle’s operations as to how the heavy loads being carried can be lifted up to allow the material to be deposited on the ground behind or below the truck. Crowds are still fascinated with the workings of this vehicle and gather at construction sites to watch this commercial vehicle perform its job.

How does a dump truck do its job? Listed below are the features of this vehicle that allow it to function and perform its necessary work.

Basic Dump Truck Design

Although there are numerous types of commercial dump trucks on the market, there are distinct similarities in their design. There is a cab connected to a box on a hoist frame, with varying numbers of axles beneath both cab and box. The cab contains the engine, usually a diesel engine. Although the box may lift or empty in different directions depending upon the particular model, all of the trucks have some type of lifting mechanism that is typically mounted between the cab and the bed.

Basic Lifting Mechanism

The bed of commercial dump trucks is lifted so that the contents can be dumped behind, below or alongside of the truck at a particular location. A lifting mechanism is located at the front and rear of the hoist frame. This serves to support and tilt the dump body at the pivot points at the front and back of the frame. Also mounted to the hoist frame is a hydraulic cylinder that pivots the lift arm assembly which in turn exerts a lifting motion or force on the dump bed body.

The truck engine is the source of power for the hydraulic cylinder through the transmission of the truck. This power is transferred from the transmission to the hydraulic piston system by means of the power take-off (PTO). The PTO is a drive shaft that is connected to the transmission. The purpose of the PTO is to provide power to the pump that dispenses fluid to the valves in the hydraulic system. The varying fluid levels control the motion of the piston which is basically converting the fluid force of the hydraulic system into a mechanical force to allow the lift arm assembly to either lift or lower the dump truck body.

Lifting Constraints

The ability of the entire lifting mechanism to lift the load in the dump body does have some limitations. The size and fit of the pistons in the hydraulic cylinders can limit the maximum height to which the top of the dump body can be raised. The load itself can be another factor in the height-lifting limitations of the box, both by the weight of the load and by distribution in the dump body. Speed of the lifting mechanism is affected both upwardly and downwardly by the hydraulic system design and the regulator valves.

So that is how the commercial dump trucks of today function. Without the capabilities of this large commercial vehicle, the construction industry would most likely come to a standstill. We are thankful that they help in providing places to live and work; places to relax and have fun; and the roads that carry us to these destinations.