Wind Springs are used to power a variety of tools. They have to be wound up in the Coil Winder before they are able to apply charge to items.
The wind spring is used to store mechanical energy. Once wound up with the coil winder, it can be used in another winder to provide a small amount of power, or it can be used to run various tools. Note that when charging coils, they run the risk of breaking, a risk which gets larger and larger as they are wound tighter and tighter.