Friday, September 3, 2010

Designing for failure...

Traveling full time in a RV will get you pretty intimate with its inner workings, materials and how it is put toghether.

After 6 months in our Airstream Safari, I am starting to appreciate the time honored design and materials of this legendary brand. This rig is tough and designed for traveling.

As the initial minor repairs demonstrated, the main issues with this production period of Airstream is materials and design in the interiors.

The latest minor repair was an interesting case on the lack of forethought on the part of Airstream, and how a minor failure, can snowball into a nightmare.

The issue started with the failure of this type of hook & lash system in the cabinetry. It failed in a couple of places. Basically the spring based catch looses its ability to retain the open position while un-hooked and you can no longer fully close and secure the drawers. The obvious solution...to replace the part....but it seems to be somewhat of a specialty item, as it is not available in any hardware store.


Latch

With a screw driver, you can reset the catch open again...but eventually it fails again.
If not fixed promptly, the hook in the drawer starts to push onto the latch, which in turn is mounted on a horizontal piece of wood. This piece of solid wood in turn, is held in place with 2 wood screws that, unfortunately, go in into the kitchen cabinetry structure made out of particle board. With enough pushing form the failed hook/latch system, the horizontal piece of wood becomes loose.

Now, you have a bigger problem. Even if you find the rare latches, or...if you replace them with standard ones, the horizontal piece of wood that serves as the mounting base is loose.


View of the drawer area and the horizontal mounting boards on the back.
The top board with the new angle brackets.


By the way, just in case the how this affects day to day RV life is not clear...
In this condition, you can not safely tow the trailer, the drawer(s), if not closed properly will swing open in the first turn and cause further damage to the cabinetry and interior of the trailer.

Well, easy fix right? Just re-tighten those wood screws. Not so fast...
When you try to get access to those screws you find that they are about 1/2 and inch from the body of the trailer. You will need a fairy with a nano-screw driver to do the task for you...or dismantle the kitchen to re-tighten 2 miserable screws.

Even if you are successful at this daunting task, you will find that the screws become loose back very easily because they are going into particle board.

To be able to travel, I secured the mounting board with duct tape first...then with Gorilla Tape, which is better for this type of repairs.




After looking carefully at the whole assembly, concluded that the correct way to secure the mounting boards was with L angle brackets.
This way, the wood screws are not destroying the particle board, and the fix is accessible without major disassemble of the kitchen.


Designing for failure means designing with failure in mind.
What happens if this system or that piece fails?
Will it cause further damage?
Will it be easily repaired?

1 comments:

kaeschbacher said...

I think you are ready to start designing vehicles for rough-road travel. Great insights on the problems created by poor materials selection for construction.
Best to bypass particle board and use good, solid wood to start with.