Developing a Low-Cost Tilting Seat for Tanzanian Wheelchairs

Only 2% of people in East Africa with postural disabilities have assistive devices for their condition. Within this 2% of the population, only a small portion of the devices are appropriate for the user’s situation. For people with postural disabilities, sitting at certain angles for extended periods can lead to issues like discomfort and pressure sores. Tilt-in-space wheelchairs are the best existing solution for this problem, but currently existing models in the US range in cost from $500 to $4000. Combined with import prices and the available resources in Tanzania, these costs pose a large barrier to those affected by postural disabilities. Kyaro is a Tanzanian Non-Governmental Organization dedicated to making user-specific assistive tech accessible in East Africa, and, by working with Kyaro Assistive Technology, our team has developed a tilt-in-space wheelchair that addresses the needs of Tanzanians with postural disabilities, while keeping a low-cost of manufacturing. Our final prototype consists of two components: an outer frame and a tilting chair. The two are assembled at the chair’s pivot point with ball bearings carrying the load of the user. The chair has a latch mechanism that gives the ability to lock the seat in place at 4 different angles ranging from 0°-45°. The pivot design is based on the user’s center of mass being as close to the pivot as possible, minimizing the input force required by their caregiver to tilt them. Our current prototype satisfies all of our high-priority requirements, as it supports a 185 lb load through 50 load cycles, tilts, and locks at 0°, 15°, 30°, and 45°, requiring a max tilting force of 82.3 N, and costing only $47.33 to fabricate. Future work includes fabricating the wheelchair using steel pipes and true welds, like those done by Kyaro’s manufacturers, to better understand how the final product will function in Arusha, Tanzania.