This project stems off an idea I've played with for a while; I even wrote a blog post for a job application in 2019 musing about its potential design. Here's the idea: a modular pogo stick/scooter combination. I'm not sure if something like this is even worth building, but I decided to create a CAD model simply as a design exercise. I may build a prototype now that I know exactly how it will work, but for now this is just a CAD project. While I made a conscious effort to design parts that would be easy to make and assemble, I know that the process of building this product would certainly force some design changes, so I don't consider this design to be fully finished.
With so many different components, I could have never figured out how this invention would work without sketching out each subassembly thoroughly. Truthfully, I can't fully understand a design idea unless I sketch it out. I won't show every sketch I made (too many to post), but here are a few:
Here are some CAD renderings for the prototype, designed in Fusion 360. Most of the modeling work was done after sketching out my plans, but some components were redesigned on the fly. I modeled every part except for the two collars on the shaft, the wheels, and some nuts and bolts – thanks to McMaster Carr for those. I want to continue to work on the swapping mechanisms; they need to be quick and easy to use but also sturdy enough to withstand regular use. Right now the design feels a bit too "engineered" – I want to step it back more and make it approachable for anyone to use.
One thing I learned from making this CAD model is that there is a lot more design work to be done than you think. When I wrote my blog post, I thought that I had the working mechanisms of my invention fully fleshed out, but when I began this process, I realized that there was much more to consider. Mechanisms that I originally thought would involve one or two parts really had 5, 10, or more. For example, I originally glossed over the way that the scooter would turn, but I eventually found out about headsets, which can have a dozen different components. Each subassembly requires thoughtful attention. Most people think they know the basic working principle of a scooter or pogo stick, but there is so much hidden complexity. I borrowed a lot of designs from already existing scooters and pogo sticks, but my main challenge was integrating the two mechanisms together, because they each come with their own tricky design constraints. I also learned a lot of advanced solid modeling techniques and tricks through this project.
If you have any questions, comments, or suggestions for improvements, please reach out and let me know. Thanks!