Pete C. wrote:

Attention all bored structural engineers, I need assistance assessing
the viability, and if viable refining the design of some heavy lift
apparatus.

I'm trying to design a lift system that can lift a loaded (up to 60k#)
ISO intermodal cargo container 4'+ vertically so that a container
chassis or regular flatbed trailer can be backed under it for
loading/unloading similar to the way "slide in" truck campers are loaded
and unloaded. A further complication is that the lift unit should be
able to break down into components that are not more than about 150#
each, and be able to be assembled and disassembled by one person in a
reasonable amount of time, say 1hr. The lift unit can not get in the way
of the lower corner points of the container so that it can be
raised/lowered from a normal chassis with corner locks.

I've worked up a rough concept that looks like it could meet these
criteria:

http://wpnet.us/container_lift.jpg

Essentially is it two lift leg left/right pairs that attach to the top
lift points on the container, and rest with an angle plate at the
corners of the container perhaps a foot up from the bottom. The angle
plates have tabs on them that connect to shackles and chain assemblies
which use turnbuckle type load binders to pull the angle plates solidly
against the container frame. The legs are set at a small angle (5 deg or
less), to provide clearance for the trailer to be backed underneath.

The chains and binders fit in the under 150# criteria. The lift legs
should meet the weight criteria when disassembled into the outer tube,
inner tube and hydraulic cylinder components, so that those components
can be assembled while horizontal on the ground and then the unit raised
into place using a ratchet chain hoist or similar.

I own a 40' container and several friends of mine also own similar
containers. Moving these containers typically requires an expensive
crane and/or an expensive "Landol" style tilt bed trailer. With a lift
system like this the savings in being able to readily load/unload from
an ordinary flatbed trailer or container chassis would add up pretty
quickly.

Thoughts, comments, suggestions?

Thanks,

Pete C.


I move a lot of heavy equipment and before I bought my own crane I would
get the local wrecker recovery unit to load and unload equipment. They
would charge me about 120 an hour and if everything is set up the total
bill was always less than 300 bucks. The most of the recovery wreckers
can lift over 40 tons and they have two cables which makes it easier
leveling an uneven load.

John