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Group 13: Seat For Child With Spinabifida


A short statement on the project’s goal.

Taylor Madewell, Udochi Nwofia, and Ryan Roberts

Problem Statement

Christopher is a one year old boy with Spina Bifida. He requires a sitting device, similar to a wheelchair, to assist him in his mobility and strengthening of his lower body muscles. His family would like it to last until he’s old enough to walk, with some assistance. It is also intended to be a multi-terrain vehicle that can be used indoors and out.

Design Specifications

  • Must be safe for a toddler to to use
  • Must be able to be used daily for several years
  • Must compensate for growth of child
  • Must be able to be used indoors and outdoors

Background Research

Spina bifida is a developmental defect occurring when a baby’s spine fails to develop or close properly. It can lead to muscle weakness, stiffness and sometimes paralysis. There are various products, such as the Bell’s Bumbas wheelchair and th GoGrit Freedom Chair. While both of these products would be helpful to Christopher, the products have a long wait list, and the family does not know when they will be able to acquire either.

Concept Design 1

Describe concept 1, hand drawings, simple CAD, description.

Concept Design 2

Describe concept 2, hand drawings, simple CAD, description.

Concept Design 3

Describe concept 3, hand drawings, simple CAD, description.

Selected Concept Design

We created a decision matrix shown below, however we felt that a combination of different aspects of each design would make a better product.

Decision Matrix

Engineering Analysis 1

Your goal for analysis, your method of analysis, and results.

Document Fabrication Process

The majority of the fabrication was completed over the summer of 2021. With the assistance of Tennessee Technological University’s various workshops and the managers overlooking them, most notably Mark Davis and Jeff Randolph, the wheelchair was created using several tools made available to me.

The initial steps in fabrication was actually to redesign some aspects of the final design such as the driving mechanism and wheel connections. Mark Davis assisted me with this redesign and together we created a CAD drawing using new parts that would improve the quality of the wheelchair. Once the design was complete, we got to work on cutting, shaping, and bending the many beams needed to create the T-frame of the wheelchair. Then we asked Jeff to help us create a press fitting in the crossbeam to house the bearings that allow the wheels to rotate within the frame. The gear-driving mechanism that Mark and I developed is shown in picture 1, and picture 2 shows a CAD sketch of the crossbeam and gear mechanism.

After the T-frame was completed, shown in picture 3, Mark and I got to work on the wheel connections and press fitting in the gear mechanism. After some slight alterations to the beams, the back wheels were attached and the front wheel was also attached using a smaller bearing and a rod welded to the wheel. The frame at this point was free standing, shown in picture 4. We also attached two plates of steel to help align the bike chain from the to gears and provided overall stability to the frame.

We then welded the backrest frame, that we shaped earlier in the summer to the T-frame, shown in picture 5. Next we attached a seat plate and a back plate, both of which were created using scrap metal sheets and rods, shaped using various machines, and welded by Mark. Picture 6 shows the completed frame.

Finally we were able to take the entire wheelchair apart and powder coat it to apply a protective coating to the metal while also giving it some color. The full assembled wheelchair with coloring is shown in picture 7.

The final part of the project was to get some seat cushions upholstered and attached to the plates.

Testing Results

No testing has been done.


2021 Spring