Following on from 12 long years of heavy use, the existing 198 maxi boxes were showing signs of their age, with replacements being urgently required. Rather than re-manufacture what has failed before, we thought that this was an apt time to have a complete design review on the units, with a view to improving their performance of longevity.
When conducting a design review, the first items to look at are: where the original units failed in service. Firstly, the padlock and hasp style NATO locking system, was one of the items open to abuse, when keys were lost or simply left back at the workshop. This resulted in the NATO lock being prized open with a crow bar, damaging not only the lock, but the cabinet as well.
We decided to completely do away with this system and went for the standard issue, heavy duty locking system on the Polstore drawer cabinets. Not only is this a fool proof way to secure the box, but if damaged by abuse it will completely lock the box out, preventing its use. This can then be repaired in around 20 minutes, using basic tools and standard components.
We next turned our attention to the chassis, with the standard tubed tyres being replaced with heavy duty run flat tyres on re-enforced rims.
Not only improving its service life but removing down time from punctures and also allowing us to remove the spare wheel previously fitted to the units.
Areas of stress and corrosion were then re-designed and re-enforced to provide a stronger chassis and remove areas for water / sand to collect. The chassis was then painted in a heavy-duty texture powder coat system, which is more resilient to knocks and abrasions when compared to its smooth finish counterpart.
The final item was the parking brake, which previously relied on a standard wheel locking system to one of the rear wheels. This was replaced with a hydraulic handbrake system with the disc fitted directly to the new rear axle, braking both rear wheels.
This not only drastically improved the effectiveness of the brake, improving safety, but by moving to a solid rear axle (instead of the corner stub axles) a much stronger and more rigid chassis was created.
The units are now in service with the USAF and should provide them with many years of hard use and offer a substantial improvement upon the outgoing units.
Super Heavy Duty! Just what we need when rolling around flightline and transporting across the world.