Fabricating Mechanical automata - Week 01
Apart and together again
For this week I learned how hard it is to find a simple mechanical toy. It took visiting a couple of stores before I found one that was interesting (and it still had batteries included). I found a mechanical toy car shaped as a dinosaur that when pressed down spins the back wheels on their own. There’s also a small switch to turn on four LEDs in the wheels.
Figure 1. Functioning toy pre-disassembly
Rebuilding the toy took longer than I expected, and it was partially due to errors on my part. When I first opened the gearbox, the gears all flew out and I wasn’t able to see how each fit together, so I had to figure out the puzzle of how the spring and its enclosure activated the gears and spun the back axel of the car.
I also had to restart several times during the reassembly because of my missing the order of operations of parts. At first I had the gearbox and toy body put together before I realized the dinosaur head / button had to be placed inside first. The process in general was a lot of trial and error to see where pieces fit and the order they needed to be in. Making sure the LEDs stayed in place was also a challenge and the electronic components were frustrating to deal with (especially because they added little functionality to the toy).
Figure 8. Functioning spring gearbox
The toy is surprisingly complex and not what I thought. When I first bought the it, I thought the mechanism work due to a string tied around the button attached to the spring, so pressing down would wrap the string around the axel which would unwind when pressure is released. Even the cam to move the dinosaur’s mouth was a simple yet complex addition in the way the cam moved a bracket, transferring motion to the front of the toy, and pushed the silver jaw up and down.
Figure 9.
After taking the toy apart, I didn’t think I’d be able to put it back together. The gearbox was also held together by plastic clips that (I came close to breaking), so seeing it work like the original video was a good dopamine hit.