Thanks for posting that! The big issue I see with that system is that there's no backup for a cable or motor failure. Otherwise it's pretty close to what I was thinking, although I'd still want 12V just for power outages.
The original system I was thinking about had two motors/cables so that if either one failed the system wouldn't fail. I was thinking bigger wheels in a track, that way a "wheel chock" sprung from cable tension could be used as an emergency brake. But, didn't like that she'd be stuck in the elevator in an emergency, and wasn't sure if two hoists would work in tandem (need to research them more). Also if one failed and the cable got stuck, the second one would keep you from falling, but you'd still be trapped (possibly able to go up).
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@Rider and
@HRTKD reported problems with winches (one very unexpected from a tier one manufacturer). I was wondering if hoists had the same problems or not and at 18:30 he talks about the cable strands rolling over each other causing the elevator to shudder. Possibly a higher quality hoist might have a better guide to eliminate that? But even so, will they pull in tandem? What happens if one fails, how do you get out?
Hard to beat the screw-driven system for safety. Seems like it would work with and inexpensive electric motor (cheaper than a hoist/winch anyway), although a long threaded rod will easily make up the difference. What I'm not sure about is how you'd keep the threaded rod lubed and clean. Also, how do you escape the elevator if the motor fails?
@BiduleOhm also talked about a worm-drive, which I believe he meant to be the same as a screw-driven, but it sparked an idea of using a short screw to turn a cog that operated the lift -- seems like it would have all the safety and even less cost. But what I really like about the cog is that there's no cables to foul the system from going down (that is a hand-crank with a prawl could be used to lower the system for emergencies by disengaging the screw). Downside is I don't know of ready-made parts that could be reused for that (more research ;-).
Update: Turns out the brakes on some hoists work via cable friction and the #1 cause of brake failure is a contamination on the cable (grease/water). Given this would be outside with rain and squishy bugs...not a good idea. A hoist would need to have an alternative brake (e.g., brake drum) or gearing mechanism that insures no slippage (e.g., worm drive).