I am trying to design a gearbox of sorts that would climb a rope from turning a gear (motor, handcrank, etc). The largest issue is that, while both the top and the bottom of the rope will be attached to something, I cannot predict how taut the rope will be.

I was thinking about just wrapping the rope around a large worm gear and hoping that the weight of the device itself would generate enough friction to stop the rope from slipping off, but it doesn't seem like the best solution. I also thought about using a few helical gears radially around the rope, turning them with an internal gear ring that wraps around them, but this seems like an overly engineered solution that might not even work.

Any and all input is greatly appreciated.


  • $\begingroup$ Is this a project? see here: dailymail.co.uk/sciencetech/article-3458878/… $\endgroup$ – Solar Mike Dec 11 '17 at 5:28
  • $\begingroup$ I think you'll need to elaborate a bit on "I cannot predict how taut the rope will be." If that means "It has to work on both a tight rope and a loose one.", tight meaning your mechanism cannot count on being able to deflect the rope, that will constrain the solutions. It might also be helpful to indicate roughly the thickness and strength of the rope, perhaps also its composition if you know it. What might work with climbing rope may not work with parachute cord or twisted sisal. $\endgroup$ – scanny Dec 11 '17 at 6:08

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