Curriculum Vitae ~ Michael Farrow

 

MEng Aerospace Engineering Graduate

Real Engineering Examples

 

External Access Step

 

Another of my more successful projects was the development of a damage resistant external step, to allow easy access to the driver and commander side doors, and the rear troop doors. The existing step fitted to the vehicle was a piece of bent tubing looping around from the base of the vehicle, to form a foothold.

 

Rear view of detached step

Obviously, on such a mobile vehicle, these steps would regularly impact obstacles and were prone to irreparable damage. I was tasked with developing a flexible step which would allow the same level of access to the user, but deform plastically when impacted.

My first solution to the problem was to create a footplate from punched sheet steel and suspend it on two flexible wire rope sections, bolted to the vehicle.

Rear view of detached step

In addition to the extra flexibility offered by the wire rope section, the step was able to ride up wire rope when impacted to reduce it's plastic deformation. The first prototypes were not successful, as due to vehicle vibration the steps would jangle loudly.

The second generation of step was much more successful. Development improvements included a swaged section above the footplate to fix it firmly and the reduction of the swaged eye mountings at the top to allow better movement. In addition, shoulder bolts were introduced to mount the steps, to elliminate over tightening on the production line.

The completed step is able to swing freely about the upper mounting bolts, deforming when hit, but it not allowed to rattle or jangle.

Rear view of detached step

(Above) Step slightly deformed from normal position. (Below) Fully deformed step.

Rear view of detached step

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