Margaret Knight and her side project: The paper bag machine

While working as a factory employee folding paper bags by hand, Margaret Knight (1838–1914) revolutionized the industry by inventing the first machine to automatically produce flat-bottomed paper bags. Her persistence through challenges, including a legal battle over patent rights, created an invention that transformed retail packaging and established her as one of America's most prolific female inventors of the 19th century.

Knight earned her living through demanding physical labor in a Massachusetts paper factory, with long hours spent on repetitive tasks.

Inside the Columbia Paper Bag Company in Springfield, Massachusetts, Knight endured exhausting days manually folding and gluing flimsy paper bags, one at a time. Her fingers grew calloused from the repetitive work, all while receiving minimal compensation. As a woman in the 1860s industrial workforce, Knight faced restricted career advancement paths and lower wages than her male counterparts.

Her supervisor frequently complained she was wasting "valuable company time" with her constant experimenting, forcing her to strategically navigate workplace politics. To placate him, Knight cleverly suggested selling him the rights to any machine she invented—a promise she never actually intended to keep. This shrewd move bought her the freedom to continue working without interference.

During evenings in her boarding house room, Knight dedicated herself to designing a machine that could revolutionize paper bag production.

After full workdays, she sketched designs and built wooden prototypes by oil lamp, teaching herself mechanical engineering principles despite having no formal technical training. Co-workers observed that "her hands that packed bags all day would then be grease-stained and ink-smudged by night" as she pursued her invention. The human toll was real: fatigue, skepticism from peers, and the challenge of self-education in an era when women had little access to technical training.

By July 1868, Knight had created a working wooden model—described as a "rickety wood thing, all shaky" by one account—that successfully demonstrated her concept. Her breakthrough machine could automatically cut, fold, and glue paper into sturdy flat-bottomed bags that could stand upright—vastly superior to the flimsy V-shaped bags common at the time.

Knight hired a local machinist to build a durable iron version capable of withstanding factory use, wisely destroying her wooden prototype afterward to prevent copying. What she didn't anticipate was that Charles F. Annan, who had observed her iron model being built, would steal her design and file a patent application before she could submit hers—forcing her into an unexpected legal battle.

Despite exhaustion for her full-time factory work, she maintained detailed notebooks, drawings, and records—documentation that later proved crucial in her patent dispute with Annan. As Knight would later reflect on her challenging path: "I'm only sorry I couldn't have had as good a chance as a boy, and have been put to my trade regularly."

Knight's persistence transformed everyday packaging and proved that innovation can come from anyone, regardless of gender or formal education.

After a 16-day legal battle in 1870, she decisively defeated Annan's claim that a woman "could not possibly understand the mechanical complexities of the machine." The patent examiner noted that Annan's supposed improvements showed only "the skill of the mechanic, not the genius of the inventor," firmly crediting Knight as the ingenious mind behind the machine. She secured Patent 116,842 in 1871.

Knight co-founded Eastern Paper Bag Company in Hartford, Connecticut, where her machines replaced 30 hand laborers each, vastly improving production efficiency. Major retailers like Macy's and Lord & Taylor quickly adopted her sturdy, self-standing bags, transforming the shopping experience by eliminating time-consuming paper wrapping.

Her invention "attracted extraordinary attention in Europe and America," earning honors from Queen Victoria of England in 1871. Knight went on to secure at least 26 patents for diverse creations from shoe-making machines to engine improvements, establishing herself as one of America's most important female inventors.

Every flat-bottomed paper bag still used today carries the legacy of a factory worker who refused to accept that things couldn't be improved—and who fought for recognition in a system designed to overlook her contributions.