Recently I used a "3D positioner" made by PMK Mess. It is pretty awesome -- basically you move it to any position, turn the locking knob, and it stays rock solid.
How might it work internally?
I want to know how it works. I would like to be able to answer the following questions.
- How can the joints be locked in place so well using one knob in the center?
- Are there canonical mechanisms that solve this sort of issue?
- What are some good resources or references for designing something like this?
It consists of 2 ball joints and 1 DOF rotational joint. Pictures of each joint are shown below. I would take it apart, but it's not mine.