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Mechanism Geometry

  1. Jun 29, 2011 #1
    Ok, I have a problem similar to a slider crank but not quite.


    Fixed points are A and B, all others are free to pivot. The beam labeled 20 is rotating around, at this snapshot 40 degrees from vertical. How can I find how many degrees back and forth the beam that is fixed at A turns in response? I'd quite like to find a general solution

    I really can't figure out the geometry for this one :blushing:
  2. jcsd
  3. Jun 29, 2011 #2
    this can be done with some simple construction..DRAW EVERY THING TO SCALE
    Draw an arc showing the motion of the rod fixed to B.

    Then divide that arc into maybe 5 pts.Measure the length the 150 rod.

    From each of those 5 pts, draw an arc of radius 150(the 150 rod length).This shows the various positions of the 150 rod during the motion of the B rod.

    Then from A draw an arc of radius 40(the 40 rod length) to intersect.Join the points of intersection between the various points(between the 150 rod and the 40 rod) with a curve.

    I hope this is clear.
  4. Jun 30, 2011 #3
    Thank you for your reply. It is clear, however I was hoping for a mathmatical solution rather than graphical.
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