Bicycle Freewheel Mechanism

The general premise of this exhibit is to see and play with the inner workings of a common object that doesn't usually show off its guts. I thought of maybe showcasing a toaster pop-up mechanism or some other commonly used mechanical device, but I ended up choosing the ratcheting freewheel crank mechanism that is used in most bicycles.

As you can see in the video, this mechanism doesn't actually have a crank attached, so it is easiest to drive it from the toothed sprocket end. What happens is the three spring loaded ratchet pawls grip onto teeth on the inside of the sprocket when the mechanism is turned forward, but they slip and click when the mechanism is turned in the other direction.

Ideally the final version of this exhibit would have a nicer turning interface, maybe even an actual bike crank. I would also like to add a source of angular inertia to keep the freewheel spinning a bit longer in the direction of the clicks. This could come in the form of a real bike wheel.

If I could get the parts to work well together, I'd like to keep the freewheel as large and colorful as possible so the workings of the mechanism are very clear even if the rest of the parts come from an actual bicycle.

I imagine a visitor approaching this exhibit and turning the crank because it is generally understood that is what you do on a bike. Once the wheel is going, the large, bright, spinning colors and the louder than usual clicking sounds would force his/her attention to the freewheel where the mechanism is being demonstrated.

I like the learning aspect of this type of exhibit, but I don't think it has much meaningful interaction other than turning the crank to watch the mechanism do its thing, and I'd prefer it to encourage more inquisitive interactions.