What we think of as new has probably been done before if you take time to search for it. Google patents is the easiest way to search the USPTO content. We use patents as a time stamped proof of design activity which is of course traceable and a legal document.

Some Dumper History

The Dumper is a loose term covering many different machine sizes and types. The dumper being a mobile skip able to empty its own contents. The skip being a large open topped container for building materials or refuse.

A dumper could be a towed trailer incorporating a skip with an emptying function or a mobile machine with an integrated tipping skip. The skip may empty through a hole in the base or through a tipping rearward function around the rear axle area, or through the rear door via a sliding ejector mechanism or a tipping sideways action as we see in the patent examples below. The machines again vary in size from models that can navigate through a domestic doorway to massive machines used on open cast mine sites.

The first dumpers or dump box wagons were horse drawn and were used to empty ash from peoples coal fires or use in agricultural harvesting of crops.

Dumpers referred to as "Site dumpers" are the size and type of machine that are used on building sites, and range in size generally from 1 ton to 10 tons capacity and are mostly 4 wheel drive with centre pivot steering.

Early Dumper Examples

The below dumpers are early examples of the type.

A gravity based motorised dumper example from 1923 clearly based on a road going vehicle.

A High Tip dumper example from 1924. These high tip designs are very popular today on mini-dumpers so they can tip directly into a waste skip.

Advancements in the remote skip latching mechanism in 1932 must have been driven by the skips experiencing un-commanded tipping.

By 1932 we have a multistage hydraulic cylinder being used to tip the skip and a single stage hydraulic cylinder to open the rear door.

This Le Tourneau dump cart trailer is from 1930. Le Tourneau are responsible for many mining innovations and tended to trust cable and winch actuation over hydraulics in these early days. This Dump Cart was significantly strong and intended for mining use. Le Tourneau made their first articulated dump truck in 1938 based on a scraper.

An example of a hydraulic side tipping dumper trailer from 1935.

This is an interesting Euclid machine patent as a centre pivot steering mining dumper from 1963. Euclid are another big name in mining equipment and their 1Z model is thought to be the first dedicated design of off road mining dumper truck in 1934.

Muir-Hill First Site Dumper

Muir Hill Engineers Ltd of Manchester were renamed E. Boydell Ltd after Edward Boydell took over the company.

Muir-Hill are credited with the creation of the site dumper concept in 1927 based on the ever popular Fordson model F tractor reversed and the driver repositioned to the side effectively sitting over what was the front wheel. The skip was then placed over the heavy load bearing rear axle. The later model was based on the Fordson model N. You can find images of these dumpers on google.

This invention patent by Joe Davidson Coldwell assigned to E. Boydell from 1942 clearly shows a dedicated 2WD dumper frame and a layout still found today the patent does mention road use and also rough terrain use..

Basil Thwaites is a famous name in site dumpers and has made many improvements to the site dumper over time. Thwaites from Leamington Spa were a close neighbour and competitor to Benford Ltd of Warwick.

The Thwaites website states they invented the first purpose built 2WD site dumper in 1951 but this was a 6hp forward facing 3 wheeled machine with the skip at the rear and this claim does not seem to align with the Muir-Hill information shown above.