Tracks-B-Gone: Wheelchair Wheel Cleaning Device
Objective
The Craig H. Neilsen Foundation and the Shepard Center commissioned the design of a device to clean the tires on a manual wheelchair while the user is seated. The product needed to be compact, lightweight, and easy to use. It should also be reliable and effective in cleaning the user's wheels.
Skills, Software, and Applied Knowledge
- SolidWorks
- MATLAB
- Market research
- Surveys
- Presentations
- Technical Reports
- CNC Programming
- Woodshop experience
- Fabrication
- Experience working with clients and stakeholders
- Task analysis
- Specification sheet
- Evaluation matrix
- Experimentation and trial testing
- Video production
- Working with interdisciplinary peers
My Contribution
I contributed to every part of the process. My main responsibilities included research, surveying, data analysis, brainstorming, creating prototype designs, building prototypes, testing the prototypes, writing reports, and creating the final presentation and video summary.
Process
Research
Currently, there is no commercially available product to clean wheelchair tires, despite previous attempts to address this issue through university and personal projects. These previous attempts were hindered by high costs, lack of portability, limited compatibility with different wheelchair designs, and a lack of adaptability. Manual cleaning methods using wipes or brushes are often challenging and uncomfortable for wheelchair users. However, a survey revealed that a significant majority (85%) of respondents expressed interest in purchasing a cleaning device if one was available. The survey also indicated that most wheelchair users find their wheels frequently getting dirty but only clean them when necessary due to inconvenience. Among the existing cleaning methods, scrubbing the wheels with cleaner and dry brushing the tires was found to be the most effective and least difficult.
Criteria and Specifications
Low-Fidelity Prototypes
Platform Design
Curved Design
Attached Design
Three prototypes were created and ranked from 1 to 10 to indicate the significance of the criteria in the success of the design. Each concept was also weighted from 1 to 5 based on how well it accomplished each criterion. The higher the concept ranking (with 5 being the best) in the highly weighted criteria, the better the concept comparatively.
Mid-Fidelity Prototypes
The platform design was chosen for further development, and the next steps involved determining the dimensions of various components, including the ramp length, ramp angle, roller spacing, roller diameter, and brush height.
To assess the effectiveness of different brush types and heights, preliminary testing was conducted by coating the wheelchair tires with mud and rubbing brushes against the tires in a unidirectional manner, both with and without water. Visual inspection revealed that stiff horsehair and plastic bristle brushes were the most effective. The optimal roller spacing and brush height were determined by varying these parameters and measuring the force required to pull the tire tangentially from the top of the wheel using a force gauge. The effectiveness of cleaning was also compared for each brush height and roller spacing combination, with the mud test repeated for the most effective combinations.
Final Design
The final design consists of two identical units featuring two rollers supported by a frame that collects any fallen dirt, a bristle brush fixed between the rollers, and a two-tiered ramp for easier wheelchair access. The first roller includes a fixed ratchet gear that interacts with a moving ratchet arm attached to the frame, facilitating effortless egress. Grip attachments on the unit's bottom and ramp prevent slipping, while modular components ensure easy cleaning, maintenance, and transportability. The design allows for simple brush replacement without disassembling the units. Designed as a user-friendly and easily manufacturable solution, it employs simple machines to enable manual tire cleaning with minimal effort.