Hi @all,

I am a current industrial design student and I'm having an issue with a mechanical problem. And by looking through this forum I think I found quite a lot qualified guys who maybe have an idea to adress my problem.

Currently I'm designing a foldable/collapsible shelter for homeless people. These shelters are produced by a specific company and financed by advertising and donations. The shelters are quite rigid and placed at particular points in a city (and they are permanently placed there, so no carrying them around, etc.).

My problem is that after the shelter is "unfolded", the hinges should overcome the "slack point" or "dead point" so it can be tightened with a ratchet and a strap band.
I tried to illustrate it quickly so you understand better what I'm dealing with. Please let me know if something is unclear so i can try to explain it in a better way.

First, this is how the opening looks like (including overcoming this "slack point"). I thought about the mechanism in a ballpoint pen where it "clicks" and the mechanism is locked.



next....the closing movement! Actually it's just the opening movement reversed :



Next I want to show you 3 photos of a little cardboard model I made. I painted the "rubs" and hinges in, so it's better understandable how they unfold.





In the next picture I want to show, the direction in which the rods and joints are folding and unfolding:


And in this picture I wanted to give a quick overview on how the shelter looks from the top- and sideview. And also illustrate that the surfaces are angular, so it stiffens out when tightening with the ratchet strapband.

again an illustration of the folding planes:



And at last a quick sketch of how feather-hinge could maybe bring the whole thing above the slack point! Only problem is...how do I get it back to folding ??



And before I forget: The holes that are existing when the shelter is unfolded get covered by a pvc plane so that the
whole thing is closed.

Ok...I would be so appreciative if someone has ANY IDEA of how to solve this problem. I worked on this particular problem for so many hours but I think you guys have way more talent and understanding in how to solve it.

Thank you so much!
Chris