James Waldby wrote:
On Sat, 25 Jun 2011 13:41:50 -0700, Denis G. wrote:
On Jun 23, 1:24Â pm, "Pete C." wrote: [...]
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
[snip concept description]
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.
...
http://www.youtube.com/watch?v=VyKDDR9dd6k
Per http://www.ascom-italy.it/products-file.php?idc=13&idp=17 etc,
that ATS 200 has 7 times the necessary capacity. A much-smaller BHT
40 would be big enough for 30 tons, but still weighs a bunch of tons
and isn't composed of 150# pieces that can be assembled in under an
hour. Nowhere close to Pete's specs.
That is a completely different design. Note that is a fully mobile
gantry crane, while my design is four lift legs that attach to the
container and rely on the container for most of the structure. There are
no cross pieces on the top in my design nor any lower horizontal members
other than the chain binders. My design does not move other than
vertically either, so it doesn't need the extra strength that a
traveling gantry does.
I expect since a two point support condition (diagonal ends) would be
likely at points during a lift, that each leg needs to be built to
handle a 30k# load plus margin. Given that there are plenty of log
splitters with twice the capacity that are not overly massive it seems a
30K# capacity per leg is not unrealistic. Since the leg is composed of
three main sections - inner tube, outer tube and hydraulic cylinder -
which connect via the cross pins for the cylinder, disassembling those
three sections should be pretty easy. Each section shouldn't weigh much
more than the 150# goal, perhaps 200# at most.
For assembly, I expect to have a small lift frame that will temporarily
attach at the top of the container to provide an upper attachment point
for a ratchet type hoist to lift the assembled 500-600# leg into
position where it can be attached to the containers top corner lift
point. Once attached at that point, gravity will hold the leg in
position while the others are attached and while the chain binders are
attached for the lower support. Disassembly will be the opposite
sequence.
A 4" bore hydraulic cylinder running at 2,500+ PSI will provide the 30k#
lift capacity. That cylinder should be able to fit into a leg assembly
composed of something like 6" and 7" square tube of reasonable wall
thickness. That size tube would appear to be sufficiently strong for the
limited side loads involved. Remember, the trainer is moved under the
container, the container doesn't move horizontally. This is the same
concept as truck campers which routinely lift 4,000# campers with a set
of 2,000# capacity jacks.
I think the under-150#-per-piece spec is unrealistic.
It is for a traveling gantry crane, but that's not what I'm trying to
build.
Instead allow
up to say 500# each, building parts on small wagons or trailers like
items #90153 plus #37510 at http://www.harborfreight.com/, with some
of them having stabilizer support legs that swing out and pin in place.
Two parts would be left and right sides of a lift frame, to lift one
end of the container.
Again, in my design there is no lift frame, only four discrete lift legs
which rely on the existing lift frame which is integral to the
container. Each lift leg breaks down into three components for
transport.
Other parts would be sets of rollers with stands.
With one end of container lifted, insert a roller set under the end,
then adjust and brace the legs of the stand. Put the transport trailer
near the stand and attach winch between trailer front and container.
Remove lift frame, then winch container onto trailer, or possibly move
lift frame to other end of container and put another roller set or two
under container before winching it aboard.
Nope, the idea is to simply lift the container 5' vertical, back the
trailer under it into position then lower the container to rest on the
trailer just like a big truck camper. The only horizontal movement is
the trailer backing under the raised container.