How do you get a wheelchair over a curb without any lifting?

The idea for this project came to me when I spent a week wheeling my injured friend around in Washington D.C. While there are many ramps for us to access, I found that it was quicker to turn around and haul him up the curb. I quickly grew tired of doing this, so I began using the detours to wheel him to various locations. I figured that there must be some system that would simplify the motion of getting someone over a curb, and so this project was born.

The idea

Work is done when you fight gravity. When you lift someone up in a wheelchair, you are changing their vertical position, so you are doing work. If we can get a wheelchair over a curb without changing the passenger’s vertical position, then we don’t do any work.

The solution

This wheel’s individual spoke lengths can be controlled. This allows the position of the hub to be controlled as well. By the lowering the hub as a passenger mounts a curb, the change in vertical direction changes, and the passenger maintains their vertical position. In doing so, there is no work to be done in moving the passenger in the vertical direction. After the passenger has mounted the curb, the hub can readjust itself to the center of the wheel, lifting the passenger up to the default vertical position.

My Role

I wrote the algorithm for calculating the length of each spoke given the position of the hub within the wheel’s rim. This includes updating the length of the spokes in real-time as the wheel’s rim rotates. I documented every technology (to my knowledge) that could be used to implement this algorithm to position the hub within a wheel’s rim. This was then included as part of the patent.

I selected the positioning of the spokes to ensure that there was no interference between them as well as selected other mechanical components that would be required to interface rotating electrical equipment to a stationary equipment.