carl mciver wrote:
I had another one of my ideas today and it concerns needing to lift
things in my garage around my workbench and the area I usually devote to
working on engines and such. There's never enough room to set up my engine
hoist, so I have to roll everything outside or hump it by hand. I'm getting
too beat up to do all that stupid heavy lifting by myself anymore, so ideas
are welcome.
What I had in mind was to install three or so fifteen foot long barn
door tracks in the area I usually work. Suspend from them on rollers a
track (or two) that work like a bridge. Since my work area is partially
under the garage door in the up position, I need the upper tracks to be in
and out of the area, and parallel to the door track. The bridge has to be
lower than the door and track, simply because the frame that holds up the
end of the track is in the way. I'd have to have a rigid drop frame with
the upper rollers to allow the bridge to clear the garage door track.
The door tracks are available in several load ratings. The highest I
can ever see lifting is about five hundred pounds, but most likely in the
order of three fifty or so. The engines I usually work on are about that
much. If I had a double track bridge would I be able to safely double the
load rating of a single rail? I have in mind a foot or so spread between
the bridge tracks that would allow me to raise the hoist point above them to
keep the working height to a maximum. I figure the rails will be spreading
out the load between multiple beams to keep local stresses down.

The other thing to consider is the load carrying ability of my garage
ceiling. It's 2x6's on 24" centers, with 5/8" sheet rock below and
strandboard above for creating floor storage space. I could put some
plywood webs between the roof joists and the ceiling beams to give me a
little more beef, but I'm having a hard time guesstimating what will be safe
and what will be asking for trouble. My work area is one corner of the
garage, so I won't be picking things up out in the middle of the span. That
space is currently occupied by the garage door opener and screw track, which
is a point I can't cross with a device like this anyway.

The best way to mount something like this would be to put a heavy steel channel
strongback on top of the joists above the track to spread out the load. Secure
the hoist track to the strongback with long bolts through the thickness of the
ceiling to avoid weakening the joists by drilling holes in the highly stressed
lower edges. With the load spread over several joists overloading should not be
a problem. What is the total span of the joists and are they the bottom chords
of a truss roof?.