Here are a trio of prototype chairs i developed to test a few variables. All of the chairs feature the same seat, lumbar & shoulder panels (in size & build), but its the angular relationship between them that changes, as well as the leg formation. While the actual profiles are of my own design, the angular relationship between the seat, lumbar & shoulder supports are based off existing designs: two of them are nearly the same chair, echoing a Jasper Morrison design (although one has ‘sled’ suspension legs, and the other has a higher shoulder rest). The third design is based off an Eames couch (which i’m guessing was Morrison’s inspiration for his chair as well).
Besides the screws, every part of all of these were made from scrap, so you’ll notice un-color matched parts, and odd bits of PT 1-by used as intermediary mounts between seat & side panels. The profile panels were CnC’ed, while everything was built in my shop. In theory, i designed the seat panels to be some-what universal so that once i refined a profile, i could unzip them from one proto and reattached to the new!
Initially when i built these i only used hidden screws from inside the 1-by’s into the side panels such that you didnt see them from the exterior. Pretty much all of them were wobbly at this point, so i reinforced with two more screws from the outside per panel side, but this only helped marginally. The real game changer came when i added the cross brace between the back legs. THEN it didn’t wobble … a lot.
Anyways, first up is the Morrison w/ tall shoulder support. Attentive eyes will notice the puzzle joint on the right panel; i just could NOT get the scrap piece of ply i routed the profiles from to fit all 6 sides, so i had to create that joint to allow me to make it two parts. Besides a bit of sanding to clearance the two, it worked like a charm!
Pros: Pleasant angle relationships, depth of seat, leg stability with cross brace, height of shoulder support, lower location of cross brace = best.
Cons: overall seat height still pretty low (akin to a beach chair or Adirondack), the curvature between seat & lumbar needs to be lessened so those panels can approach each other better which in turn minimizes butts falling out the back,
Next up is the short back w/ Sled legs.
Below is a detail shot of how the 1-by’s were used to bridge the two components. Because this design couldn’t use a cross brace in the back (where it desperately needed it), i put it up front and it … helped… kind of… but it still listed terribly – and cracked ominously. So this one got immobilizer struts running nearly vertically in the back corners which canceled any bounce it might have had. I’m guessing the real solutions lies in doubling up the ply layers around the base, but either way more research is needed.
Pros: angle relationship, depth of seat
Cons: Stability, both lateral and longitudinal- the lengthened legs made for a very unstable platform and audibly cracked (a few times) with my weight on them, swinging from left to right as well as feeling like it might just blow out and drop me backwards!
Lastly is the Eames based proto
Pros: good angles, better seat height, stability w/ crossbrace
Cons: seat depth incredible!!! Each seat panel was 19″w x 14″d and the Eames could have easily been a 19″ square. This cross brace was set higher (again, another test), and i think the lower placement did better to firm up lateral sway.
Overall: the two non-sled designs were by far the better proto’s, although the Eames had too deep a seat, the cross braces were necessary & should be sat lower to maximize effect, and the curvature between seat & lumbar should be minimized to allow the planes to closer approach each other. The taller options for both lumbar & shoulder seemed to be the hit (when neighbor & wife were consulted), and i’m willing to bet most people would not fight a higher overall height.