Tuesday was another relaxed day without power. Ben and I got to the shop today hoping to brainstorm improvements for the chair. He was curious as to how they were able to bend the hand rims on the wheels 360 degrees. I walked him outside to show him the jig, which is a table which they lock to the ground, and the table had two circles, one 25 cm radius, the other 14 cm, with the small one on top of the short one. They put the pipe into the bender and walk it around till it creates a circle. I had tried doing this on the first day, but it didnt work. The hand rims are a smaller tube, so it is able to bend easily. The armrest needs to be larger to support the weight of the user as they transfer in and out of the chair. So when you try to bend the larger tube, it crumples when the stress gets too large. After ruining a large amount of steel the first day trying this, I had given up on it, trying to minimize the materials I used. But today we decided to try bending another tube by bending a little bit, shifting the tube, bending a little more, and continuing this until the whole pipe was bent (a little over 1/4 of a circle). We then checked it against the armrest we made in Boston with the hydraulic bender… it was a near perfect match and certainly would work!
We decided this would be the best size for the armrest, something we had concluded on in Boston, but wanted to test a larger size with someone here. Because we were wasting time trying to get that size work, we figure this one will do just fine. With that positive feedback, Ben and I continued to roll, as we improved on the locking mechanism for the armrest by putting a bushing through the armrest for the bolt to easily slide into. Ben also came up with an efficient way to tying a string to the bolt for a quick and easy release. After running out of things to think about, we went into town with Daniel to have our seat sewn together.
Ben and I were happy with the way the day ended up. We celebrated by ordering Chipsi Mayai, a french fry omelette. It was surprisingly tasty.
Yesterday, Ben and I fixed the seat to the wheelchair, put the wheels on, and began riding it around looking for problems. There was an immediate and apparent problem to the front wheel locking mechanism. The pipes were not bending, but they did begin to separate at the joint and a slight angle appeared (between the base and the front pipe). I spent some time thinking about the forces acting on the joint, and realized we needed to put a bolt in from the bottom to push the smaller pipe which runs through the inside upwards. Knowing the high torque put on the joint by the caster wheel, which is at a large distance and high force, and knowing the bolt would have to be added close to the joint, I wasnt too sure what would happen. What ended up happening was that the pipe was pushed down onto the bolt with such great force that it began to dent to pipe. This was bad. We tried troubleshooting it by adding another smaller pipe to reinforce it. It wasn’t great, but would do for now. Without much hope for the joint in the future, Ben and I decided to ask Daniel about Tish’s mechanism, as he knew more about it than we did. “Oh, its in the back if you want to see it!”… I guess I probably should have asked a bit earlier in my trip…
Ben and I checked it out, and man was it stable. It was ten times better than the mockup we had made in Boston. We rode the chair around, and realized it was much better than ours stability wise, though it takes much longer to take apart. So after some deliberation, Ben and I decided we would remake the bottom part of our chair, matching what Tish had made except for its folding aspect. Seeing her chair confirmed some of my suspicions that I had early on when making my prototype for the lock, but I had no time to investigate these suspicions. So, yet another lesson learned.
We took our chair back to the hotel with us to have Zakeria test it today. He rode it from our hotel to the main road. The street we are staying on is the worst road I have ever seen, and is a great off-road test for our chair. It seemed like the chair did pretty well, though near the end seemed to be veering to the right a bit. Once we got to the bus stand, Zakeria stood up on his crutches to watch us fold it, as he had yet explained it to him, and wanted to show him once before he did it. When we took off the front wheel, I immediately saw that the inside tube had separated from its welded position… I couldn’t let anyone sit in the chair for fear that they would get hurt. We helped pay for Zakeria’s motorcycle taxi ride because we felt bad for causing him trouble, and assured him we would make a better one for him to test.
So we ended up going to the shop to return the chair and solidify our plans for Friday when there is hopefully power. After we confirmed what we would do, I decided Ben would be able to build that part of the chair and I could work on the jig tomorrow. Before cutting some of the material I would need for the jig, I decided to confront Daniel about something that would have to be said eventually. I didn’t want to waste material building a jig if they were never going to use it, so I asked him about his thoughts on putting the chair into production. When I asked him this during the first week, he told me that yes, people would buy it. Today, he told me that they would try to make four or five chairs on their own and set them in the shop to see if people would want to spend the extra money on it (even though most of the money comes from donors). He told me that he would estimate raising the price from 420,000 TSH to 500,000 TSH ($53 increase). Im not sure about the cost of the materials that would be added on, but this seems close to reasonable, maybe a bit high. His answer was something I expected, but Ben did not. He did not like hearing this, and I too realized Daniel’s plan didn’t make sense logically.
I then began looking for scrap parts to make a prototype. I found some sheet metal that was twisted about in every other direction. Using the table clamp, I was able to straighten it out well enough for a prototype. I got all the parts I needed to make a rough go at the jig, and with luck there will be power and I will be able to work on that tomorrow.
I am pretty happy with were we are at. Though I know we could have been at this point after the second week, I realize all the times I have failed have helped me realize the wrong way to do it, and find the right way. So unfortunately I wont be able to build any attachments for the wheelchair, but I think by the time I leave next Saturday we will have our primary objectives fulfilled. It is hard to believe I only have 9 days left! Ben and I are going to try to make the most out of them!
