Answers.Body: <p>Would this solve your problem? Depending on the direction of the input, only one axle will turn.
  <img src="https://i.sstatic.net/ySowI.jpg" alt="Depending on the direction of the input, only one axle will turn"></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-12-25T00:52:47.043Z
Answers.Text: Does this solve @Ari Porad 's problem? The best resolution you could get with this device is 1/4 of a turn.
Answers.UserDisplayName: MindS1
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-12-25T20:34:44.903Z
Answers.Text: ^ Why would you say that? It's free to rotate as much as it wants, because the four-lobed "Gears" will simply slip underneath the angled stoppers, in one direction.
Answers.UserDisplayName: RallyToMe
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-12-25T21:24:39.657Z
Answers.Text: @RallyToMe, technically MindS1 is right, it could take as much as a quarter turn until the knob wheel gets locked. This can however be reduced by using ordinary gears, the more teeth the smaller the error at the price of increased size.
Answers.UserDisplayName: zovits
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-04-15T17:00:23.523Z
Answers.LastActivityDate: 2014-04-15T17:00:23.523Z
Answers.UserDisplayName: zovits
Body: <p>I need a mechanism so that if a (NXT) motor rotates forward, it moves one gear, but the other stays still, but if it rotates backwards, the first gear does not move, but the second one does. </p>
  
  <p>I found an example solution for one half of the problem <a href="http://www.youtube.com/watch?v=v_IstqVQB8A" rel="noreferrer">here</a> (I would need 2 of these), but that seems like it would take part of a rotation to pick up, and I need mine to be really precise.</p>
  
  <p>I am building this for the Z-Axis/Extruder of the <a href="http://reprap.org/wiki/NXTStrap" rel="noreferrer">NXTStrap</a>.</p>
  
Tags: <nxt><building><technic><gears><mechanical>
Title: How can I make a precise one-way clutch using Technic elements?
UserDisplayName: Ari Porad
ThreadText: # How can I make a precise one-way clutch using Technic elements?
  
  (Asked by: username_0 on 2014-04-12)
  
  I need a mechanism so that if a (NXT) motor rotates forward, it moves one gear, but the other stays still, but if it rotates backwards, the first gear does not move, but the second one does.
  
  I found an example solution for one half of the problem [here](http://www.youtube.com/watch?v=v_IstqVQB8A) (I would need 2 of these), but that seems like it would take part of a rotation to pick up, and I need mine to be really precise.
  
  I am building this for the Z-Axis/Extruder of the [NXTStrap](http://reprap.org/wiki/NXTStrap).
  
  **Tags:** nxt, building, technic, gears, mechanical
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2014-04-15. Score: 15 | Accepted answer
  
  Would this solve your problem? Depending on the direction of the input, only one axle will turn.
  ![Depending on the direction of the input, only one axle will turn](https://i.sstatic.net/ySowI.jpg)
  
  > **Comments:**
  > **username_2**: Does this solve @username_0 's problem? The best resolution you could get with this device is 1/4 of a turn.  
  > **username_3**: ^ Why would you say that? It's free to rotate as much as it wants, because the four-lobed "Gears" will simply slip underneath the angled stoppers, in one direction.  
  > **username_1**: @username_3, technically username_2 is right, it could take as much as a quarter turn until the knob wheel gets locked. This can however be reduced by using ordinary gears, the more teeth the smaller the error at the price of increased size.  
  
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