I'm trying to get a single side of a mechanical parallelogram (with 2 bones parallel and equal in length) to carry the "Neck Base" along a fixed angle as a parallelogram only allows.

I've tried restricting the movement of the bone within the IK chain (pictures show that there are none, but I did try) to allow zero rotational movement, but the "Neck Base" still rotates weirdly and not smoothly. It reacts the same way without any of said rotational restrictions, if that helps.

I do have a Bone Constraint on both "Neck Rod Front" and "Neck Rod Back" to share the same rotation angle in only one axis as shown.

Is there a way to connect "Neck Rod Back" to the "Neck Base" to maintain that angle?

Is there a better way to complete this method of movement?

Here's a link for the file for testing.

https://ufile.io/wmhn6


Pictures:

[![Rest Position][1]][1]
Rest Position

[![Forward Position][3]][3]
Forward Position

[![Up position][4]][4]
Up Position

[Short Gif][5]


  [1]: https://i.sstatic.net/SwzRe.jpg
  [2]: https://i.sstatic.net/7FOXU.jpg
  [3]: https://i.sstatic.net/ubm44.jpg
  [4]: https://i.sstatic.net/RdRR2.jpg
  [5]: https://gfycat.com/ConstantConstantAruanas "Gif"