This was an earlier brain child, that just reached maturity. It might require too high of voltage out current, but it would be a cheaper build, maybe. Less precision, definitely. Oh, and it would look sick. Do a looped one sided flexible chain. Each link would have matching electromagnets. As the links move down, creating the lift if you will, the motors and wheels being at the bottom of the chain, the links would run against a brushes that wild activate from that new link on down. Add in a couple diodes, and as the links were retracted, the magnets would disengage.
Like I said, I need to do math on how much current/voltage I’m talking about. EMF might be an issue. Pace makers. Small metal bits. Whatever.
What about a zipper. Yet again, make the chain only roll one way, but instead of magnets, have two chains, with opposite facings, zippering together.
I’d love to just go inspector gadget, but that seems the most complicated, mainly due to the number of concentric rings I’d need. That and how to actuate them is kinda slippy.