QL+ Students from Cal Poly designed and built a rear-wheel wheelchair lift for Army Veteran, Tammy Landeen. Tammy is a 10-year Army Veteran living in Maine. She was injured in a horseback riding accident in 2005, which caused her to become paralyzed from the waist down. She is very active and enjoys spending time outdoors, regardless of the season.
Tammy asked QL+ to create a device that would allow her to easily and independently change the tires on her wheelchair. Before this device, Tammy had to have assistance from others to replace her wheels to keep from tracking mud and sand into her house. Much like when you remove your shoes coming into your home, Tammy needed a way to exchange her outdoor wheels for her clean indoor wheels.
After the team interviewed Tammy, a list was created of the highest priority needs that are necessary for this project. The device needs to lift her and her wheelchair to allow her to change her tires. The highest priority needs that the device must satisfy are as follows: the design must not damage the wheelchair in any manner, the device needs to be independently operated without the assistance of another individual, the device needs to be quick and easy-to-use, and the device must be stable during use and possess high reliability. Additionally, it was mentioned that the device needs to be able to accommodate multiple styles of wheelchair tires up to 1/2 in radial difference. The device needs to fit within Tammy’s enclosed porch and have as small a footprint as possible while still satisfying all needs. The device will not be an attachment to the wheelchair and instead be a stationary device that will be installed in Tammy’s porch. However, the device needs to be freestanding and not require any hardware to mount or attach it to the porch. For convenience, the device needs to be lightweight and not require excessive mechanical power to operate.
As a result of the three-ideation sessions, the span of the project solutions was narrowed down to five concepts. Of these five concepts, three were selected for construction into physical concept models. The team decided to move forward with the Lat-Pulldown Model. After some preliminary testing, the team concluded that a simpler lifting device would sufficiently meet the project requirements. They decided to progress to an electro-mechanical system. In the team’s new design, they removed the mechanical pull-down mechanism, changed the axle interface material from aluminum to UHMW (Ultra-high-molecular-weight polyethylene), included a linear actuator to life the user from below, and made it “push button” actuated, per Tammy’s request.
We are very proud of this team and their work!