I've been working on an idea, but am finding myself stumbling against a few limitations, both in my knowledge base and in my supply lines, tho I thought I might throw out a question here and see what sticks to the wall, so to speak...
I'm trying to work out a straight pull (as opposed to something involving a lever, like a come along) lifting rig that will act as a force multiplier to allow an exertion of 30 pounds of force (or so) at a time to be applied to lift a trapeze bearing a rider from a single central pulley. I can put together a block & tackle style rig without too many problems (I've done rigging for stage professionally, and a bit on my own time for pleasure, natch), but I'm trying to determine the best way to make a doubled safety system to reduce the chance of accidentally shock loading the system back to the lifter, because the intent is to have the system hooked up to some potentially delicate body parts.
I was thinking using ratcheting pulleys in at least 2 positions in the block & tackle rig, but haven't worked with them in a bdsm context before and don't know much about them, and the only ones I've found with an idle eyeball search have a 150 pound weight limit, which is perilously close to the weight limit I'm aiming to be able to lift.
I'm reasonably sure that there has to be some good equipment along these lines in either nautical or rock/mountain climbing applications, but neither is a field I really have any experience with.
Any suggestions anyone?