I've always had a certain fascination with contraptions that move on wheels–even to this day. Bikes, scooters, skateboards, etc. My sophomore year of high school, I got this random idea to "spring-load" a skateboard, so that it might be more fun to ride, and it just wouldn't get out of my head. Every so often, the idea would creep back in, and I'd think, "hmm, this could actually work". So I tried it.
I got the inspiration from seeing unique, well-designed spinoffs of the traditional skateboard, such as electric skateboards, Freebord, a skateboard designed to mimic the feel of a snowboard, and the Sbyke, a skateboard-scooter hybrid. That, and I just really wanted to build something cool. I had been sketching down invention ideas since I was a kid, but this was the first time I actually made a serious prototype. Over the course of a few years, I designed, built and patented this invention, even going so far as to license it to a major toy company, YVolution. Check out my design process, and please, let me know what you think!
This is one of the first rough sketches I drew (and I mean really rough), freestyling my thoughts on paper. I can't say exactly how the idea popped in my head–I think it was more that I was searching for interesting ideas.
Don't try to read my handwriting, here's what I wrote (on right):
"Spring-loaded skateboard for progression use
push down to activate spring
the force of the spring will increase pop in ollie
for a higher jump"
Not exactly the most advanced way to put it, but I was just rushing to get my thoughts down on paper, trying to keep up with my thinking.
As a litmus test for my idea, I thought of making a scale prototype before jumping into the full thing. My parents took me to Toys R Us (rest in peace), and I bought a pack of Tech Decks, the popular mini finger-skateboard toys. I felt a bit embarrassed (I hadn't played with Tech Decks since elementary school), but I was more excited to start building. I thought, "how can I build this with common household materials?" My answer came in the form of pen springs and Krazy Glue. Pen springs had the perfect size and shape, and could be bent into shape fairly easily. At my makeshift desktop workstation, I sawed through the plastic board with a kitchen knife, twisted the spring into shape, and glued it on to the board. I played around with it, showed it to my dad and a few friends, and we noticed a difference–hard to tell from such a small and lightweight prototype, but noticeable. I wanted to keep exploring.
refining the design
Before building a full-scale prototype, I made a few tweaks to the board's design. Mainly, I switched from just one torsion spring to two, allowing for more stability and power. I also flipped the rotation direction of the spring design, such that the spring's coil's contract and the inner diameter decreases as it is rotated. I didn't know this at the outset, but later on learned that this is a fundamental principle of torsion spring design.
I made the prototype from an old skateboard I had lying around the house, and fashioned the springs from hand grippers (on right). I couldn't find springs that rotated as described above, however, so I had to use these, which rotated outward. Not ideal and more likely to wear down, but they worked great for a first prototype. I received a lot of help from Tom Harvat, an engineer and friend of my dad's, with this being the first experience I ever had working in a machine shop. I definitely couldn't have done this without him.
I found torsion springs with adjustable set screws, so I used this opportunity to make the TorqBoard adjustable for different weights. You can easily loosen the set screws and swap out for springs of different resistances.
Manufacturing process: Tom and I started by cutting the tail off the skateboard deck with a bandsaw. We then laid out how the springs would attach to the board, and cut the hand grippers to fit the desired shape. We also cut and welded pieces of scrap metal into a base for the springs. After bolting everything to the deck, we painted the board a sleek matte black and electric green.
The finished product.
Some demo action shots.
Thats it! If you have any comments, I'd love to hear from you.