February 17 - April 10 2024
3D printed model of our final toggle cover design
The goal of this project was to design a product for a client in a power wheelchair to help improve their day-to-day life.
Our team decided to focus on designing a protective toggle cover that would attach to the client’s wheelchair armrest and protect their hand and joystick from rain, snow, or moisture in general. Therefore our design involved the following objectives:
Because our design had to fit on the wheelchair armrest, had to be portable for the client to attach and detach, and make economical sense, our constrains were:
Our final design met and exceeded all of these criteria while staying within our constraints.
March 2 2024
To get ourselves familiar with the problem we were approaching, we were assigned to do research on the client’s condition and potential solutions to the everyday issues she faced.
We had set our sights on protecting the client and their wheelchair from rain and snow, so I decided to do my research on canopy covers for wheelchairs. I found that they did exist but were extremely expensive; many being upwards of $1000. I therefore tried looking into potential ways of constructing a similar product at a fraction of the price.
I also considered using linear actuators to motorize the canopy cover so that deploying and retracting the canopy could be done at the push of a button.
Existing canopy covers costing upwards of $1000
My research on linear actuators
March 2 - March 9 2024
Once we were familiarized with our client’s situation and potential remedies to the problem of her travelling outdoors in the rain and snow, we started brainstorming for prototypes.
I made several revisions of the canopy cover. The first design involved the use of linear actuators and motor controllers that would extend and retract sections of the canopy, all being controlled by a remote attached to the armrest.
However, I quickly realized this design was overcomplicated, and switched to a similar design using fishing line so that the product would be more lightweight and waterproof. Unfortunately, this design proved to be too complicated as well.
Linear actuator motorized canopy design
Fishing line motorized canopy design
Multiview of manual handle canopy design
Engineering drawing of manual handle canopy design
CAD Model of manual handle canopy design
My final iteration of the wheelchair canopy cover involved a manual canopy cover, just like the ones I researched in my assignment. It used a long handle positioned on the right side, which was the client’s more mobile side.
To my utter disappointment, my group and I realized that given our time constraints, something as complex as a deployable canopy cover for a power wheelchair was out of our scope of expertise. As a result, we shifted our focus to only protecting the wheelchair toggle, which was also something the client mentioned was a problem.
March 9 - March 16 2024
My group and I made several initial prototypes of the toggle cover design.
We initially started with plain rectangular boxes models for the hand. We saw this as an adequate first start to cover prototyping, but knew this design could be heavily improved upon.
Physical model of the initial toggle cover
Low-fidelity CAD Model of the initial toggle cover
CAD model of the first iteration of the toggle cover
Shape of the toggle
For our first iteration of the toggle cover, we shifted to a sleeker half trapezoid design as we thought it would better contort to the shape of the armrest in which it would attach to as well as minimizing the chance of water buildup inside.
Once we proved that this design could work, we quickly created a second iteration of the prototype with better dimensions to fit the hand, as well as some slots for replaceable plexiglass covers.
We 3D printed this second design as well as cut out some plexiglass inserts, and the product turned out great!
However, after putting the cover through our testing plan, we discovered that there were some minor issues we had to address.
For one, there was no slot on the top to secure the plexiglass inserts on the side. This meant that after enough water built up on top of the cover, it would dribble down the side of the cover and into the cover. Thankfully, the water would just spill out after getting in due to the slope on the inside, but it still wasn’t ideal.
The second issue was that the top part of the cover was not strong enough. One of the joint sections actually broke and had to be hot glued back together.
To address both of these issues, we decided to add slots on the top section of the cover.
Printed and assembled second iteration of the toggle cover
CAD model and image of plexiglass inserts for the design
March 16 - March 23 2024