Issues with Jansen Linkage

There are two main concerns I have with the Theo Jansen linkages, which have shown up in rough prototypes.

If the node that I have labeled as F in my drawings, referenced in the previous blog post, can get even a little bit out-of-plane, it can collapse towards the fixed node, B.  I will certainly try to ruggedize the hinges at F, and hope that solves the problem.  I am already planning to make linkage BH and GH extra wide (out-of-plane) to establish some degree of out-of-plane stability...  i.e.  keep the walker from collapsing if it gets pushed sideways.

Another tricky issue is that in a practical build, with some width and depth to linkages, segment CH comes very close to fixed point B.  This can be an issue for me since I was planning to give the axle at B a large diameter since it would extend out as a structural component for out-of-plane support.  Worst case, I might need to curve linakage CH a bit to make sure that it does not contact anything connected to the main axle at B. 

I hope there will be no need to make motion-stops around some nodes, or guides to keep linkages in--plane.

Two tips from a veteran

1, scale up

2, concentrate on the joints: find your perfect compromise between makebility and precision (you will have to make tons of them)

3 (bonus tip), find (and use) the tag “theo jansen” or “strandbeest” on LMR