Margaret E. Knight

• Born: February 14, 1838
• Birthplace: York, Maine
• Died: October 12, 1914
• Place of death: Framingham, Massachusetts

American mechanical engineer

Credited with about ninety inventions and twenty-two patents, Knight is best known for a machine that made square-bottom paper bags, which continue to be widely used in grocery stores and in homes.

Primary fields: Business management; household products; packaging

Primary invention: Paper bag machine

Early Life

Margaret Ethridge Knight was the daughter of James and Hannah Knight. Born in 1838 in York, Maine, Margaret later moved with her family to Manchester, New Hampshire. She always displayed an interest in subjects associated with males and claimed that she would rather have a jackknife than a doll. At a young age, she developed a reputation as a tomboy, and her inventiveness pleased her brothers, for she made kites and other kinds of toys for them, while she devised a foot warmer for her mother. Her father gave her free access to his tools, and when he died, while she was still a child, they were passed on to her. Her mother was left with the task of rearing her and her two brothers in a mill town.

Manchester, which was named for an industrial town in England, in Knight’s time employed fifteen thousand people in its factories and produced 360 miles of cotton cloth a day. Her brothers worked in a mill, and Knight, a very serious child, learned about the importance of machinery when she brought her brothers their lunches. She came to realize that manufacturing was a dangerous way of earning a living. At the age of twelve, she witnessed a young working girl injured in the Amoskeag Mill by a shuttle that came loose from a loom. This accident inspired Knight to develop a device that could quickly stop a loom, and eventually all looms in Manchester were provided with them. She also had the experience of working in a cotton mill herself. She was not the first woman to receive a patent, as has sometimes been claimed, but she learned, while still a teenager, about patents and how to prepare them.

Life’s Work

Knight’s education took her through secondary school; then, like many single young women, she had to find a job. She was a tall and strong young woman with great determination to improve the efficiency and safety of factories. In 1867, while working at Columbia Paper Bag Company in Springfield, Massachusetts, she began to devise a machine that would produce bags with square bottoms so that the user did not need to hold them erect. A man named Charles Annon also was interested in this process, but Knight suspected that Annon was copying her work by spying on the machinist she hired to make her model. Annon argued in his defense that as a woman she could not have understood the complexities of such a machine. Examination of her notebooks and diary proved otherwise, and she won her claim in court in 1870 and earned her patent. Shortly thereafter, she cofounded the Eastern Paper Bag Company in Hartford, Connecticut.

From that time on, Knight invented many items. In 1883, she devised a skirt protector, which was a shield that fit between the outer and inner walls of the elaborate skirts that women wore at the time. It protected the inner surface from rain, snow, and dirt and was secured by a waist belt. The following year, Knight invented a clasp for holding together robes or textile fabrics.

By 1889, Knight was living in South Framingham, Massachusetts, where she would spend the rest of her life, and had turned her attention to machines for cutting shoes. She devised a machine for cutting India rubber and other materials used for the soles of boots and shoes. The machine consisted of an endless apron, or belt, with a series of tablets, or beds, flexibly connected and able to move horizontally beneath a pattern and a blade that had a vertical reciprocating movement. The material would be clamped on an apron, and a complete sole would be cut out on each of the tablets. The apron would carry both the soles and waste material out of the machine. In connection with shoemaking, Knight also patented a numbering mechanism. Working with a man named Charles S. Gooding in 1894, she designed a machine for imprinting or stamping numbers or other characters on products such as boots and shoes.

Also in 1894, Knight filed a patent for a new design of window sash. Realizing the difficulty of cleaning window panes by merely raising and lowering the sashes, she devised a frame whose sashes did not simply operate vertically but would swing horizontally outward. This improved window frame and sash, now very common, seems not to have come into frequent use until a number of decades later.

By the end of the century, Knight was working on compound rotary steam engines, and in 1902 she patented an improved engine with a new arrangement of cylinders and a new construction of the valve that supplied the steam. She followed this the next year with a new deployment of pistons and their abutments to prevent vibration of the engine. In 1903, along with John M. Benjamin, she patented an automatic tool for boring or planing concave surfaces or the surfaces of cylindrical chambers in rotary engines. She continued to work on improvements in internal combustion engines. In 1910, when she was in her early seventies, she patented a spring wheel with a resilient hub to increase ease of motion in automobile tires.

Knight’s working life extended nearly to her death. Called “Lady Edison” by her supporters, she worked in a variety of fields, devising items for women, for households, and for factories. She suffered from pneumonia in 1914 and died on October 12 at the age of seventy-six.

Impact

It is sometimes difficult to determine how long or how well some of Knight’s inventions worked. She assigned her improvements on engines to the Knight-Davidson Motor Company in New York. Inventions such as her skirt shield would of course not outlast the full skirts of the late nineteenth century, and steam engines that she worked to improve were rendered obsolete by electrical engines. She turned to the needs of the day over a period of more than forty years while the manufacturing world saw many changes. As someone who had almost reached senior citizen status when automobiles began to appear, she ended her career working on improvements in automobile wheels.

Although it is actually simpler than some of her other machines, the paper bag machine has been Knight’s most famous invention. Today, more than seven thousand machines in the world produce flat-bottom paper bags, and despite the fact that many plastic bags are used in grocery stores, customers continue to ask for flat-bottom bags and even to buy them if grocers do not supply them with their orders. People continue to use paper bags around their homes.

Despite the patents that Knight was granted, her labor does not seem to have been well rewarded. When she died in 1914, her estate was valued at less than $300. Her work has not been forgotten, however. In 2006, she was inducted into the Paper Industry International Hall of Fame.

Bibliography

McCully, Emily Arnold. Marvelous Mattie: How Margaret E. Knight Became an Inventor. New York: Farrar, Straus and Giroux, 2006. Although this book is intended for young readers, it is one of the most recent and easily available sources, describing the difficult working conditions of Knight’s time. Illustrations.

Macdonald, Anne L. Feminine Ingenuity: Women and Invention in America. New York: Ballantine Books, 1992. One of the best books on female American inventors. Includes several references to Knight, with emphasis on the paper bag machine.

Vare, Ethlie Ann, and Greg Ptacek. Mothers of Invention: From the Bra to the Bomb—Forgotten Women and Their Unforgettable Ideas. New York: William Morrow, 1988. Describes Knight’s stop-motion device for a loom.

‗‗‗‗‗‗‗. Patently Female: From AZT to TV Dinners—Stories of Women Inventors and Their Breakthrough Ideas. New York: Wiley, 2002. The authors picture the original model of the paper bag and include drawings from Knight’s patent.