Margaret Knight (1838-1914)

Margaret Knight is best known for inventing the machine that makes flat-bottomed paper bags in 1870. Knight grew up a tomboy, famous for her kites and sleds. She preferred jack-knives, gimlets and wood to more feminine toys. Her father died when she was 10 forcing her to work in cotton mills and factories to help support her family.  At the Columbia Paper Bag Company she was paid one-third the wages of the men who did the same job.  Women at the time were considered inept at keeping machines in order.  The company’s square bottom paper bags were hand glued and expensive.  

After working nights at home for 10 years, she built a model machine that cut and pasted square bottom bags. She commissioned a Boston machinist to build a working prototype so she could patent her invention.  While the machine was being manufactured, Charles Annan attempted to steal her idea and patent it himself.  At age 33, Knight filed a patent interference lawsuit accusing Annan of copying her invention.  She hired a patent attorney and paid him $1,600 to fight her case. The court was reluctant to grant her the patent because it believed a woman with no formal mechanical training could not have possibly developed a complicated machine. Her case was ultimately won in 1871 with the help of her journals and sketches showing the 10 year development of her ideas.

Today, Knight’s paper bag machine remains a milestone in the history of mechanical engineering. With financial backing she established the Eastern Paper Bag Company.  She is referred to as “Lady Edison” for her 27 mechanical inventions, from valves to rotors for cars to leather cutting devices. Her original paper bag machine is in the Smithsonian Institution.