eli5 How do pull cord music boxes work?

Question

I assume they’re very similar to wind up ones, but how does the cord work. Where is it stored? How does it avoid getting twisted or knotted up? Also as they’re often used in children’s toys how are they waterproof?

In: 3

Answer 1

With a wind up music box, you put energy in by turning the key, which pulls the spring which then works the mechanism. With a pull cord one, you put in energy in by pulling the cord, which pulls the spring…

The cord is wound around a bobbin inside it, so it doesn’t knot.