Margaret Knight

Women in STEM
Women in STEM
Margaret Knight

Birth: February 14, 2016

Death: October 12, 1914

Specialty: Engineering 

Major Contributions:

Invented machine that folded and glued paper shopping bags

Held over 20 patents 

Inducted into Inventors Hall of Fame

Image: Wikimedia

Later this month the National Grocers Association will host its  Annual Best Baggers Contest Finals. When we think of those paper bags used at grocery stores across the country – the machine that made them possible – was invented by a woman. 

Margaret Knight was born in 1838 and at the age of 12 her first invention was inspired after seeing an accident at a textile mill. Her device automatically stopped a machine if something became caught in it and was quickly incorporated into mills across the country. A few years later, in 1868, while working at a bag factory she concluded that there must be a faster way of producing the flat-bottomed bags that were made by hand and therefore very costly. 

She spent three years working on her design and building a working wooden model, but to receive a patent she needed an iron model which she hired a machine shop to create. After the first iron prototype was created she took it to a different shop to refine and eventually filed for a patent only to have it rejected. It seems a man visiting the first machine shop had seen Knight’s machine and copied it and claimed the patent for himself. 

After expensive litigation in a patent interference lawsuit she was able to show evidence that she had in fact invented the machine and was granted the patent in 1871. Thus an entire industry was changed with the ability to mass produce what are now called self-opening bags. Stores saw the appeal of being able to bag customers’ purchases rather than the time consuming task of wrapping them with paper and twine and quickly began using the bags.   

Her bag-folding machine was only the first of over 25 patents she was awarded and an estimated 100 total inventions created  before her death in 1914. For her work she was inducted into both the Paper Industry International Hall of Fame and the Inventors Hall of Fame in 2006. So, next time you grab a quick lunch from your favorite fast-food establishment, take a minute when you pick up your bag to think of Margaret Knight and her amazing inventions.

Written by Angela Goad


Famous Women Inventors: Margaret Knight

Wikipedia: Margaret Knight

Paper Industry International Hall of Fame: Margaret Knight

See Also:

Diverse Voices: Women Inventors – Margaret Knight

Meet the Female Inventor Behind Mass-Market Paper Bags

NGA Best Bagger Championship

National Museum of American History: Patent Model for Paper Bag Machine

Ready, Set, Bag! Documentary Website