Margaret Knight fought a sexist employee to claim her rightful title as the inventor of the flat-bottomed paper bag in 1858. She was working in paper bag factory when she noticed how difficult it was to pack things into the flimsy, shapeless sacks. So, she decided to invent a machine that folded and glued paper to make a flat-bottomed bag.
Knight spent many late nights drawing up plans before creating a wooden prototype. She couldn't, however, obtain a patent until she made one out of iron.
While it was being produced at machine shop, an employee named Charles Annan copied her idea and got a patent for it. Knight sued Annan for copyright infringement. Annan argued that, because she was a woman, she couldn't have been the true inventor. However, Knight's sketches and detailed plans helped her win the case. She ended up establishing her own paper bag company and received large royalties for her invention.