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How do I arrest a rotation at any angle

  1. Feb 5, 2015 #1
    How would I go about creating something like a hatch, that could be arrested at any instance. I am looking for a solution for a 0-90, 90-180, and 0-180 degree range.
    A 360 degree solution such as a whiteboard, would work just as well. If you know how this can be made, or know a link that illustrates building plans, please say so.
  2. jcsd
  3. Feb 5, 2015 #2

    Simon Bridge

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    The two pics illustrate two methods.
    i.e. the whiteboard is held against tilting by the screws at the pivots to either side. The hatch is held up by pneumatic rods.
    There are many other approaches.
    What's the problem?
  4. Feb 5, 2015 #3
    What other approaches do you know?

    Problems arise in the details. I need detailed parts and plans.
  5. Feb 5, 2015 #4

    Simon Bridge

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    The problem here is that your question is too general ...

    You could use a ratchet, hydraulics, and extendable stick, a bit of gum, a peg, your hand, a friend, magnets, a motor, gravity... it goes on.
    You have provided two examples of how you may go about holding a hatch open at an angle of your choosing.
    Well done: you have answered your own question.
  6. Feb 6, 2015 #5
    The rotation could be restricted to a pre-determined angle by using a spring loaded detent. The detent mechanism is fixed on the hinge of the hatch or the white board.
  7. Feb 6, 2015 #6
    I need the building details. Whatever complete solution you know, please explain it in detail. If you know more than one, start with the simplest.

    Machinekraft, I need to arrest the board/hatch at any angle
    Last edited: Feb 6, 2015
  8. Feb 6, 2015 #7


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    It is impossible to give building details if you don't explain in detail what you want to do. And even then: designing something for your specific application could be a lot of work, don't expect everyone to be happy to have the opportunity to work for free.
  9. Feb 6, 2015 #8
    This is an open-ended question. I don't expect anyone to build this the way I want it built. I know there would be many ways to approach this, but in order to maximize responses, I leave it to each member to answer in a way that is most comfortable for that member. This is a rudimentary problem. I'd expect anyone with some engineering background would have some kind of solution.
    Last edited: Feb 6, 2015
  10. Feb 6, 2015 #9
    What about a bike drum brake ?

    Attached Files:

  11. Feb 6, 2015 #10
    After google searching in order to gain some kind of understanding as to what it is I am looking at, I don't see how this would arrest and fix a surface.
  12. Feb 6, 2015 #11


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    Welcome to the PF.

    The problem with asking your question in that way is that it wastes a lot of other people's time. As engineers, we want to know what the constraints are going in, so we can start to home in on some good potential solutions. Even when brainstorming, we want to know what constraints are fixed, and where we have freedom to innovate.
  13. Feb 6, 2015 #12
    Could you be more specific?
    The constraint is to arrest a range of motion of 360 degrees, or just 45 degrees. The illustration of the whiteboard is also a constraint. An explanation of the lock knob with an illustration would be great.
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