I built a lifting frame as shown in
http://www.metalworking.com/dropbox/_2000_retired_files/LIFTER.TXT
Note the use of the chain! The cross beam can take far more load in
compression than in bending.

I have used mine to lift a 500Kg (1100lb) tote of alfalfa cubes up out
of a trailer. The trailer was then moved out of the way and the tote
lowered.

My come-along is a chain and lever type rated 3Tons doubled, 1.5T
single.

Ted