Recently, a community member asked “The Green Machine” for a mechanism that allows a person to push their wheelchair from its side instead of the back. This allows the “pusher” to easily communicate with the individual in the wheelchair. The team was intrigued by this opportunity and decided to take on the challenge! We looked through similar designs of this concept and gathered ideas from team members and mentors. From this, we designed a working prototype with 3D CAD software (SolidWorks) and produced a model using a 3D printer.
At the beginning stages of the project, we understood that some sort of handle on the side of the chair had to be created for the wheelchair to be pushed in that way. We had spare plastic piping that could be constructed into a “L” shaped pole which could act as a sideway handle for this wheelchair. Then, we needed to connect this piping to the wheelchair. Using CAD, we attempted several designs. The first two models we tried were unable to grip onto the wheelchair properly, they were not strong enough to hold-up to the intended use. We discovered that the 3D printed models required PLA plastic filament, which isn’t as strong as other plastic materials like PET or PVC. We continued to increase the density of the plastic in order to increase strength, until we reached a suitable model (see image here to the right).
While this design did work as intended, it proved unreliable during use. This led to another brainstorming session, during which it was suggested that we modify the tubing (the “L” shaped pole) in order to fit in one of the existing crevices on the wheelchair. Instead of the “L” shape, we adjusted both the length of the pole and the shape into an “I”, which is held in place by an attached bracket (see this photo of the adjusted model here to the left).
This was a fun project for us as a team, a smaller version of the “here’s the problem, what’s the solution” challenge that we face every season when designing and fabricating a robot. We practiced brainstorming, prototyping, iterations, fabrication, and repeated this cycle until we found a solution that helped solve the problem faced by our community member. Thank you again, to the individual who trusted “The Green Machine” to create this mechanism, and we look forward to seeing it in daily use around Edina High School! – by Jimmy V.