inspired by Strandbeest structure

May 1, 2015

The work of Theo Jansen inspired the design of Ragno, which means "spider" in Italian. The gate of this crawling creature is dictated by the ratio of the lengths of each linkage. The ratio I used for this design is consistent with the "Golden ratio" that Jansen explains in his work.

The components that comprise the spider include 1/8" MDF laser-cut linkages (~115 pieces), 1" 2-56 screws to hold the joints (~40 screws), and 1/4" stainless steel shafts to hold the entire assembly together (5 rods). In total, the assembly took 3 hours.

I ultimately settled on linkage system that used multiple layers of woven linkages to add support and structure to the piece. I have seen this been done before, and noticed that the structures tend to fall down from lack of support, so I wanted to improve upon this design, while maintaining aesthetic.

After iterating through a few different exterior designs (above), I settled on a straight arm system (below) that bulged by the joints, to ensure that the material wasn't too thin that it would fracture upon assembly. The holes were designed to be close-fits if the piece was sandwiched in the middle and threaded if it was on the exterior (last piece that screw comes in contact with).

After assembling the entire structure, I soon realized that there was too much friction in the joints, making it very difficult to move. This is mostly due to the size of the hole in the joints and the draft angles that the laser cutter puts on pieces that are cut from the machine. Future iterations will have post-ops that make each of the holes concentric and bearings in each joint to ensure motion that has less friction.