pulleys in hands vs range of motion

For discussion of hand designs.
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pulleys in hands vs range of motion

Postby nathanstenzel » Mon Mar 02, 2015 4:43 pm

It may add a little bit of parts and complexity, but if we use a set of pulleys for each tensioner wire, we could multiply the range of motion that we can get out of a hand, if it has strength, but not much range of motion. We could probably also use the pulleys to trade some range of motion for strength. We would just need to make sure that the strings go through guide slots whenever we use pulleys so that the strings do not slip off the pulleys.

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Re: pulleys in hands vs range of motion

Postby laird » Tue Mar 03, 2015 6:32 pm

Very interesting idea. I could imagine pullies attached to the tensioner pins, so the lines double back to the palm and tie off. That would double the finger movement for the same range of motion. It's an interesting tradeoff between range of motion and force of motion.
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Re: pulleys in hands vs range of motion

Postby Peregrine Hawthorn » Thu Mar 19, 2015 6:32 am

In my experience, you want to maximize your grip strength by using as much range of motion as comfortable to open and close the fingers. Hands that use a smaller range of motion carry dramatically less of my strength through to the fingers.

So far, it's actually been the size of the hinges that determines the range of motion needed to close the fingers. I'd be curious to see another simple mechanism that could do the same, preferably without making the cable go around any tight corners so monofilament cable would work.
Heavy duty hand user, and co-designer of the Talon.

I break hands and then tell you how I did it.

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