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.