Many years ago I worked at Jamba Juice. I was getting bored with the day to day grind and managed to convince my stores General Manager and the District Manager to let my build a a prize-wheel. The idea was simple: customers who were having trouble picking a drink could give the wheel a spin, and if they’re lucky they might win a free drink as well. Below is the original graphics I designed in Photoshop for the face of the wheel:

I designed the center of the wheel to look like a blender whipping up a smoothie, you can see the metal blades in the center. I sorted the smoothies in the same order they were on the Jamba menu, and padded the areas with bonus prize slots.

The actual wheel was a pre-made wooden circle available at most hardware stores. I bought the biggest size available. The knobs around the edge are also prefabs I simply screwed into pilot holes I had drilled beforehand. I gave the whole thing a nice orange coat. I had the graphics printed out at a Kinko’s and attached them to the wheel with spray-glue. Around the edge I hammered in nails where the black lines radiated outward. The wheel was complete!

To build the frame I just bought some pre-threaded galvanized pipe from home depot, plus some tee-joints and right-angle pipe fittings. I stuck some generic rubber feet on the bottom and covered everything with a sexy chartreuse green. One interesting challenge that I completely overlooked was the assembly of the pipes. As you can see below, two of the sections have pipes making a complete square… The problem is connecting the last two bits. Once everything is attached, how do you rotate/twist the last fitting to screw it on the pipe?

My solution was to screw the horizontal beams in super-tight on the right, then attach the left sides and unscrew the horizontal beams slightly, while simultaneously screwing them into the other side…. if that makes sense. To reiterate I had to unscrew the horizontal pipes from one side while screwing them into the other to keep a nice balance.

To build the flipper, I printed out a template and headed over to my local Tap Plastics. I had two identical pieces of Plexiglas cut for a few bucks. I used this and a couple bolts to sandwich the Jamba logo graphic I had printed out.

Below is the public facing side of the flipper all done:

For the flipper mechanism I used a bunch of off-the-shelf hardware parts and a little creativity. I’ve labeled everything below, but here’s a run down of the process:

• I got a U-Bolt style clamp and a couple lock nuts. I clamped the u-bolt upside-down to the top green pipe, leaving it’s exposed threads pointing upwards.
• I drilled two holes perpendicularly in some threaded couplings, and screwed them half-way on the u-bolt legs.
• I inserted a threaded-rod through the drilled out couplings. Now I had a threaded rod that could rotate and was mounted above the wheel.
• I used lock nuts to attach / clamp down the flipper.
• I used lock nuts to attach / clamp down a piece of plumbers tape to the back of the threaded rod – this created a lever-arm.
• I attached a couple springs to the lever-arm to give the flipper some tension, and mounted the the springs to the top-green pipe.

In the end, when the flipper turns left/right the threaded rod rotates inside the couplings supporting it, and the lever-arm at the back of the threaded rod turns with the flipper but is constrained by the springs.

Over all, the project came out so-so. It looked great, but had some problems. First let’s take a look at the finished thing. Below is a shot right after it was finished, and a video of it in action. Warning, I filmed it on an ancient camera phone circa 2006/2007, so the quality is pretty bad.

If you watched the video, you may have noticed that the wheel comes to a stop pretty quickly. The wheel was heavy, which was a good thing, as it stored momentum. But it also put a lot of pressure on the joint creating a lot of friction. The project would have benefited greatly by having the wheel on a bearing. Another problem were the nails – they were too weak or the springs were too strong. I didn’t imagine it would be difficult to balance this, but when building prize-wheels it’s important to balance the strength of the flipper vs. the intrinsic strength of the nails/pegs you’re using. Another flaw was the beam holding the wheel. Since the wheel was heavy, it would slowly rotate the green-pipe holding it up. Over time, the wheel would be crooked and unusable. I think I later fixed this issue by drilling some holes / bolts in to the T-Joints securing this pipe so it would be locked and unable to rotate. The U-bolt holding on the flipper would also get torqued and loosen over time. I think the main problem was the springs being too tight. I could have let gravity control the flipper, but then you wouldn’t get that satisfying “click!-click!-click!-click!-click!-click!-click!–click!—click!—–click!—–click!———–click!-” sound.

We installed the prize wheel at the store and a handful of customers got to play with it. Over all it was a fun project and some fun memories. My coworkers reacted to the project in different ways. When I was excited about building it, one of the girls was like “so what?” I couldn’t imagine how she wasn’t impressed by my craftsmanship, so I asked her why she didn’t like my design. “Design?” That’s when the light-bulb went on and she realized this wasn’t some kit-sent from corporate, but rather, something I just pulled out from scratch. Another coworker eventually got jealous and tried to destroy it. Punk. But at least it got a month or so of display time before it was falling apart on it’s own anyway.

And finally, here’s a close up:

October 28, 2013 at 6:23 am | Other Projects