Pretty sure it’s the same as an epi-pen as well.
It blows my mind. It’s a disposable, single use device that at the press of button:
1. Inserts the needle in your skin, 2. Slowly presses the plunger until the dose is injected 3. Then retracts the needle with plunger
Three distinct and seemingly opposing motions. With timing. All in a little plastic enclosure. It sure I can think of a toy with that kind of mechanism.
Edit: I took one of these cars apart as a kid to see how it worked. This site brought back a lot of memories. The little coil spring inside the gear. I have to get my hands on one of these now…
They did still produce a version relatively recently (looks like they're discontinued entirely now?), but the cars were significantly lighter and less powerful, all-plastic where the originals had metal bodies
Then I leaned on it and discovered it makes a starting noise and vrooms the engine.
I felt like I was 10 years old again.
Gears are all around us. Clocks, cars, bikes, even your printer has countless gears! For the purposes of this analysis, we'll focus on two properties of gears: gears can be used to multiply torque and used to change speeds.
Why is torque important here? Winding the spring in this toy requires significant torque. But this is product for kids, so how can we make it easier for them? The answer is gears! Gears give the kids a mechanical advantage. Now the kids only need to input a modest force to wind up the stiff spring.