Bob Engelhardt wrote:

I think it's a Good Idea. I can see where you'd be all keen to do it G.

I think (no professional basis here) that the critical issue is rack
prevention. For your 4' lift I would try to leave 4' of leg in the
tube. Just seems right.

A standard container is 8'6" high, a high cube is 9'6". Since the lift
leg attaches at the top, that makes it 8'6" long, which given a 5' lift
stroke leaves about 3' overlap which should be enough given the size of
the tube.

Also, the lower point of attachment to the
container is vital for rack prevention. Instead of a foot up from the
bottom, I think attached to the bottom would be way better. If it
starts to rack, it could run away and be REALLY exciting.

It can't be at the bottom since that would interfere with the lower
attachment points to connect on a container chassis. Any racking forces
really end up applied to the container frame via those angle plates near
the bottom, rather than pulling out since pulling out forces on one leg
inherently translate into pushing in forces on the opposite leg. Recall
that the container frame is not only strong enough to handle top lifting
the loaded container, it can also handle 5 or 6 loaded containers
stacked on top (over 400,000#). They really are incredibly strong.


I think that the 5 degree inclination could be a problem. I figure that
after being extended 4', the legs want to be 8" further apart. How are
you going to handle that?

I don't see it as a problem. I've seen plenty of lift trucks and cranes
that have their outriggers set at more significant angles and the feet
slide just fine as they spread.

As far as backing a trailer under it: how wide is the trailer compared
to the container? How much margin?

8' wide container, 8' wide trailer or container chassis. With the leg
spread, I'd expect to have 6" of clearance at each side. A truck camper
being loaded on a dually truck usually has about 3" clearance per side.