Method

To design a folding chair, I looked up other designs of folding chairs. This was so that I
could refer to their mechanism and perhaps use those references to my own design. However, this proved to be a harder challenge than I initially thought. As far as I could tell, there were two main problems that stood in the way.

The first main problem was the splitting of the backrest and seating. While it is common
knowledge for folding the chair flat. I could not do this, especially, if I wanted to use “Seiza” as the seating. This can be explained by three points. The first being the mechanism. The seat’s thickness and choice of material, plywood, would not be able to handle the stress of holding on to the mechanism together much less allowing the seat to fold in and out. The second problem is the attachments of the mechanism would interfere with the seating. As the seat is quite small, the user would completely cover the seat. If anything was added to the seat via screws or nuts it would be felt by the user. Inlaying the screws or bolts would not work as the plywood is so thin that breakage is inevitable. Finally the third problem was time. I did not have time to explore other possibilities.

The second main problem was the 3D nature of the “Seiza”. Which would not fold flat
even if you separated the backrest and seat. The 3D curves stand out. In fact, most
mechanisms that are used for folding chairs do not work for this design. As the 3D curve would interact with them. So there was a lot of time in thought to getting the chair to lay flat.

After going through a number of iterations via model making I decided that the best
method was to have pipes be shaped in a rectangle that fit each other on the inside. These rectangles are shaped slightly differently, however, they can still fold flat. These slight differences in the rectangles would allow the legs to stay together when closed. With the rectangles’ opening it would allow the seat to lay “flat”. On one of the rectangles (outer rectangle) I cut out and reattach a section of tubing to allow that area to rotate freely. This section is also where I would attach the seating to the legs. For the chair aspect, I would be using magnets to hold the chair’s position when folded out. To hold the distance between the legs, when folded out, I used steel cables. These cables also encouraged users to not push the legs the opposite way. As the cables would bend, something that the steel cables do not like and provide resistance/push back when opened in the opposite direction.

The final iteration of the prototype involved using aluminum. As it was much lighter than
steel. This was essential, to me, as portable items are synonymous to being light. This was so that they could be easily carried. This particular base could be held by my pinky with no strain, as an example.

I also made steel brackets that were loose, and welded shut on top of the aluminum
pipes. These steel brackets are where the magnets were going to be placed as well as the seat itself. It also was where the cables come in and are crimped at the ends.

Reflection: What Worked?

The prototype works like a folding chair and despite the prototype’s weight can easily
support a user’s weight. The prototype has a few ways to prevent users from opening in the wrong direction. The first being, the cables are made of steel and are unyielding. As such they prefer to be straight and not tangled if pushed the other direction. The cables’ tangledness also prevents the legs from opening up too far in the other direction. The second is the direction the seat is facing. As the seat cannot overrotate due to the rectangles being smaller than the seat itself. This helps encourage users to open the seat in the correct orientation. 

This was the first time that I worked with aluminum and was really happy that I was able
to use them to make a prototype. There are a few issues, and overall I am happy that I got the chance to work with it as compared to steel.

As the chair uses the “Seiza” seating the chair feels nice to sit on as well as following
through with the meditation aspect.

Reflection: What Could be Improved?

The problems are on the technical side, on my end, rather than its comparison to
“meditation” chairs. As in terms of design and concept, it matches what I set out to do.

In the first and last frame of the image, above, you can see the chair being used and
carried. Yet these legs do not stay flat, if at all. It is moving all over the place. While I had designed the rectangles to stay flat when closed. The seat’s 3D curvature pushes the interior rectangle just enough to break them apart. I needed to reshape the interior rectangle’s attachment to the chair so that it could match the seat when folded flat and thus not disrupt the bond.

As anyone can tell from these images, the seat completely remained the same. Worse
yet, I did not make a way to have the seat be secured when folded flat. This can be seen in the first and last images when the seat is being carried. The seat moves with wild abandonment and you would need to secure it with your hands. While this can be done with a single hand. It is disappointing to not carry it, however, you choose.

In terms of making the chair flat. It would require a different material than plywood. Or
perhaps a design that can allow for collapsibility. Although that remains to be discovered as I did not have the chance to explore the possibility.

The magnets used for this project were perhaps a bit too powerful. While it did its job, in
preventing the chair from slipping out, it had ripped itself off from the seat it was secured on to.  For one reason or another, the epoxy and scratched surface of the painted seat did not want to stay together and it took a lot of regluing to get them to stay together.

Lastly is the welding job of the aluminum is quite poor in comparison to my steel welds.
While this was the first time I had successfully welded aluminum together it is not a pretty weld.  I could have tried to redo it. Although, with so little time left for this project. There was little to be done. So in this regard, it is something I wished to improve on to have a cleaner look.