For a woman who holds between 27 and 87 patents (depending on who you ask) and whose been called the most 'famous 19th century inventor" I am somewhat puzzled that her claim to fame is her invention of the Paper Bag. Prior to Margaret's approach to making paper bags, all bags looked more like large envelopes.
Probably one of Margaret's most significant inventions in my opinion was a stop-motion device that could quickly shut down machinery to prevent workers from being injured in the factory she was working at. However, at age 12, she was too young to file a patent (and probably didn't have the money or the education).
Margaret's fascination with machines continued throughout her life and her inventions ranged shoe manufacturing to a series of rotary engine designs for automobiles.
But what impressed me about Margaret as much as her inventions was that she was one smart lady who was not about to let someone else get credit for her hard work.
Knight built a wooden model of the device, but needed a working iron model to apply for a patent. Charles Annan, who was in the machine shop where Knight's iron model was being built, stole her design and patented the device. Knight filed a successful patent interference lawsuit and was awarded the patent in 1871.With a Massachusetts business man, Knight established the Eastern Paper Bag Co. and received royalties.
This victory was not small feat and probably one of her greatest accomplishment in my opinion. Margaret appeared to have lived a very creative life and certainly deserved to be inducted inducted in the National Inventors Hall of Fame (2006)