antique Universal metal lunch box w/ slide out drawer, WWI vintage lunch pail 1913 patent dates

Antique Universal metal lunchbox with unusual slide out side opening. No thermos, though there's a wire rack at the top interior to hold a bottle or maybe just a glass beverage bottle. Original leather handle is intact and overall this is in really good condition though it's over a hundred years old. Patents dated 1913 are embossed on the bottom of the box.