"Don Foreman" wrote in message
...
On Sat, 6 May 2006 16:52:18 -0700, "Steve B"
wrote:

Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg
at
the top with a diagonal brace that comes in at 21" on the 48" horizontal
and
150" vertical. I have used one pin at top and bottom, using a grade 8
1/2"
bolt that will fit into sockets top and bottom. The lifting point is
approximately 3" in from the end of the 48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the
middle
of the 150" section with a 150# load? I really think that the maximum I
would lift with this is 21 gallons of water in the winter. Mostly, less
than 50# of groceries including the lift basket. Just a convenience
device
to keep us from making several trips up and down the steep stairs
schlepping
bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries
or
firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the
actual
lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at
least.

So much to do. So little time.

Steve


With 150 lb at 3 feet from CL, your moment is 450 in-lbf. That's
equivalent to a 3 lb load on a cantilevered 150 inch beam, neglecting
the weight of the beam itself -- which doesn't apply here with a
vertical column. Too lazy to get out Machinery's Handbook, but that
doesn't seem like a lot. Note that if the beam does deflect much
then the moment increases so it's an unstable situation.

Could you translate that to a clueless newbie version?

My greatest concern is the top mounting plate. I made a saddle for a 3 ply
2x6 beam that is 18" long. The insertion hole for the pin will be 2" out
from the end of the beam, giving the saddle 16" of contact with the beam.
There will be nine 1/4" x 2" lag bolts. The beam it is attached to is only
supported by an 8x8 post, and that post sits directly onto the top deck, not
running through to the ground or anything solid.

The bottom pin will go into a receiver that I made out of 2x2 square tube,
and welded 8 pieces of rebar onto to go into the concrete form I will make
around the base. I think the base will be substantial, and far steadier
than the top. The base should have no tendency to kick out, as it will go
down subgrade. The top is the weak point.

Again, as I said, this is a convenience grocery hoist, and probably will
lift no more than 50# at a time. Mostly in the 25# range.

But it sure is going to be spooky using it the first time with a test load.

Steve