Welding goggles. You would open them to prepare for your work, close them to make the weld, open to check where you are at and reposition, etc. You can see that the spring on the left side (when worn) is positioned in a way to hold the lids open, and also to make the lids snap closed if you flick the handle. Additionally, the long tubes for the eyes help protect the wearer from light generated from other nearby operations. These would also be perfect for naps.