I'd never heard of this, but I gotta say, it seems like an incredibly bad idea. Quite aside from the fact that I imagine the mechanics of it would be tricky (And thus likely to go wrong, like half catching and then slipping off halfway through the lift)...belts aren't designed to take that kind of a load.
Positing a very well made 1.5" leather belt, with a 1.5" overlap which is completely coated with a high quality rubber cement, then a double locking line of stitching with a 100 tex cotton thread at a 1mm spacing, and assuming that the leather is of sufficient quality that it's breakage can effectively be disregarded. Further positing a Stryker MX-PRO stretcher with a weight of 81 lbs and a normally weight distributed pt who weighs 215 lbs.
By doing some basic research (Which really just took the WA out of my WAGs, but admittedly left the G), and some rough back of the napkin calculations, I figure you've got about 30 cycles before the glue shears, and then about another 20 before you start popping stitches (The first 2-4 will have a few cycles in between popping, after that I'd anticipate a catastrophic failure.) And bear in mind, this is assuming an exceptionally well made belt.
PS: Have I mentioned that I was most of the way through an engineering degree before I dropped out to pursue EMS? Also, I spent way longer on this than I expected to, I'm assuming no one cares about how I arrived at those numbers, but if you're interested, let me know, I'll gladly share.
