Impact Testing Thwaites Cabbed Dumpers


As the leader in site dumper safety, Thwaites have manufactured and offered machines fitted with cabs for over 30 years.

Today the 6-ton and 9-ton range are both available with cab options. Thwaites were keen however to go one step further. In a controlled environment an impact test was conducted enabling an assessment of the structural integrity of the cabs fitted, if impacted during the loading procedure by an excavator.

For the test, a standard 9 tonne Thwaites Dumper was selected, the excavator used was a 14tonne machine (as it would most likely be on site) with a fully extended boom, slewing a loaded bucket at full speed.

The ground conditions for the test were wet, with the environment on the Thwaites proving ground created to be consistent with those found on site.
The standard fit cab on all Thwaites dumpers is compliant to ROPS (Rollover Protection System) & FOPS (Falling Object Protective Structures) ISO 3471 & ISO 3449.

The test criteria, brief and execution were conducted by Thwaites Engineering Manager Bob McElvogue who divided the test into two sections.

Test 1:
This test was to assess the structural integrity of the cab by striking the unit at the ‘A’ pillar.

Test 2:
This test was to assess the structural integrity of the fully finished cab by striking the unit at the front via a screen guard.

The findings of test 1:
No failures were observed or reported on inspection, the energy of impact was absorbed through the cab structure.

The findings of test 2:
No failures were observed or reported on inspection. The screen guard performed well in absorbing the initial impact with the force being distributed through the cab frame.

Thwaites are pleased to continue to offer these cabbed machines to the market. Subsequently Thwaites 6-ton and 9-ton dumpers are now recommended by the Major Contractors Group for use on their projects by main contractors, sub-contractors and hirers.

Important Recommendations:
The Contractors Plant-Hire Association (CPA) via a stakeholder working group produced and issued in May of 2019 The safe use of dumper guidance.

The guidance included the following section:
Using dumpers safely depends on a number of factors including planning, supervision, selection of a suitable machine, competence of personnel, effective exclusion zones and keeping within the operational limits of the dumper. If any of these are deficient, the risk of a serious accident increases significantly and it is therefore essential that all of those involved ensure that dumper operations are properly planned, managed, supervised and carried out safely by competent people.

Thwaites recommends that in conjunction with the CPA guidance and HSE (Health & Safety Executive) guidance that operators do not remain in the cab during loading. Always carry out your own risk assessment before operating any item of plant equipment and ALWAYS wear a seat belt.