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One-way rotation mechanism

  1. Jul 4, 2017 #1
    Does anyone know if the following is available as an off-the-shelf component and what would it be called?
    One-way rotation mechanism
    Has detents or stops at specified intervals (such as every 90 degrees)
    Fairly small - for attaching an approximately 2" diameter wheel or circular disc to
    Doesn't require a lot of force to pull it out of the detent and begin rotation again, rotates freely with minimal friction
  2. jcsd
  3. Jul 4, 2017 #2


    Staff: Mentor

    It sounds like you are describing a ratchet and pawl.

  4. Jul 4, 2017 #3
    Yes, I've considered this. The question is whether it can be specified to rotate freely + have stops at specified intervals such as every 45 degrees. Any advice on good suppliers where something like this could be sourced would be appreciated.
  5. Jul 4, 2017 #4


    Staff: Mentor

    That mechanism is used in everything from wind up wrist watches to megaton winches. So you'll have to be much more specific in your requirements before shopping.

    Strength, environment, materials, durability, teeth per revolution, the list of properties goes on and on. Your question is far too broad.
    Last edited: Jul 4, 2017
  6. Jul 4, 2017 #5


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    Science Advisor
    Homework Helper
    Gold Member

    A ratchet and pawl can rotates pretty freely. Depends on the strength of the spring. If that's a concern then more info is required. What do you mean by "freely"? How freely? Not even any air resistance?
  7. Jul 4, 2017 #6


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    Science Advisor
    Gold Member

    Really depends on whether you want a precision indexing function or just a sequential stop go stop go function .

    There are many standard mechanisms and almost as many books describing them . Probably many of these books are now available online .

    Try searching on 'indexing mechanisms' and 'intermittent motion mechanisms' .
  8. Jul 5, 2017 #7


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    Gold Member

  9. Jul 6, 2017 #8
    Cheapest way to understand them is to buy one......don't pay more than 10 bucks for one.


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