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[Travis] tells us about a neat actuator concept that’s as old as dirt. It’s capable of lifting 7kg when powered by a pager motor, and the only real component is a piece of string.
The concept behind the twisted string actuator, as it’s known to academia, is as simple as putting a motor on one end of a piece of string, tying the other end off to a load, and putting a few twists in the string. It’s an amazingly simple concept that has been known and used for thousands of years: ballistas and bow-string fire starters use the same theory.
[
hackaday.com]
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I wonder if this is practical for 3d printing. It's rather simple in construction, rigidity of the may be an issue.
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Here is a video of an arm using this principle.
[
www.youtube.com]
