Born into a family of inventors, Mary Beatrice Kenner had innovation in her blood. As the first African American woman to hold five patents—including her revolutionary sanitary belt for women—she transformed daily life. Yet, racism in the American industry ensured she never earned a dollar from her groundbreaking ideas.
A Home Full of Ideas and Bitter Lessons
When Mary was born on May 17, 1912, in Monroe, North Carolina, her family was already making its mark on American ingenuity. Her grandfather, Robert Phromeberger, invented a railroad signal light and a wheeled stretcher for ambulances. Her father, Sidney Nathaniel Davidson, a preacher by profession, spent his free time designing the impossible. In 1914, he patented a clothes press so compact it could fit in a travel suitcase.
A New York company offered Sidney twenty thousand dollars for his patent—an enormous sum that could have changed his family’s fortune. However, Mary’s father refused, believing he could profit more on his own. He manufactured a single press and sold it for fourteen dollars. This story became Mary’s first lesson on the gap between talent and financial success.
Bitter irony didn’t spare her grandfather either. His signal light invention was simply stolen by a white man. In early 20th-century America, a Black inventor could have a brilliant idea but legal protection remained the privilege of those with the right skin color.
The Six-Year-Old Who Wanted to Fix the World
Every morning, young Mary was awakened by the shrill squeak of the door her mother used. One day, six-year-old Mary asked: couldn’t someone invent a self-lubricating hinge? She immediately got to work, cutting her hands as she experimented with metals and lubricants, yet never losing determination.
While her peers drew dragons and race cars, Mary designed practical solutions for everyday problems. She came up with a folding roof to protect passengers in open cars from rain, designed a sponge cap for umbrellas to absorb dripping water, and even drew plans for a portable ashtray that could attach to a pack of cigarettes.
In 1924, twelve-year-old Mary regularly visited the U.S. Patent and Trademark Office in Washington, D.C., combing its halls to check if anyone had beaten her to a patent for any of her ideas. No one had. She took inventing very seriously, even as a child.
Dreams Interrupted
After graduating from the prestigious Dunbar High School in 1931, Mary began studying at Howard University. Unfortunately, after eighteen months, she had to drop out due to financial difficulties. The Great Depression spared no Black families, even those with million-dollar talents.
At that time, women—especially Black women—were systematically pushed out from academic and scientific institutions. Mary never obtained a diploma or formal technical training. Everything she accomplished was the result of her own determination and her family’s inventive heritage.
Despite the lack of formal qualifications, Mary never stopped experimenting. For years, she worked on solving a problem that affected millions of women worldwide: menstrual hygiene and the associated discomfort.
An Invention That Could Have Changed Everything
In 1954, Mary Kenner filed a patent for an adjustable sanitary belt—a breakthrough design that eliminated the chafing and irritation women experienced with existing hygiene products. The patent was granted in 1956.
The Sonn-Nap-Pack Company showed interest in her invention. It seemed that, after years of effort, Mary would finally achieve financial success.
However, when company representatives met Mary in person and saw the color of her skin, they immediately withdrew from negotiations. In 1950s America, a product invented by a Black woman was unacceptable to white businessmen.
Mary never earned a cent from her most significant invention. The patent expired and entered the public domain, allowing other companies to freely use her idea. Later, she improved the design by adding a moisture-proof pocket, but history repeated itself.
Five Patents, Zero Profit
Between 1956 and 1987, Mary Kenner received a total of five patents, making her the record-holder among African American women inventors. She shared one of these patents—for a toilet paper holder—with her sister, Mildred Davidson Austin Smith. Mildred herself patented and successfully sold a board game, continuing the family’s traditions.
When Mildred was diagnosed with multiple sclerosis, Mary responded the only way she knew how: by inventing a solution. In 1959, she patented a special basket that attached to a walker for people with disabilities. For Mary, inventing was never just a path to wealth. It was a way of solving problems for the people she loved.
In 1987, at 75, Mary received her last patent: a wall-mounted back-washing brush system for showers or bathtubs. Until the end of her life, she remained focused on making daily tasks easier.
Mary Beatrice Kenner died on January 13, 2006, almost completely unknown to the wider public. Her story, like those of many Black inventors, remained in the shadows for decades, with their contributions to civilization either minimized or attributed to others.
Only in recent years has her legacy begun to surface. It was even discovered that she had a daughter named Jasmine who grew up in southern Dallas—information that remained virtually unknown for years, as if Mary’s very life was meant to be hidden from the world.
Margot Cleverly
Margot's journey into women's history began with a box of forgotten letters in a Cambridge archive – suffragettes whose voices had been silenced for over a century. Since then, she's been on a mission to uncover the stories history overlooked.
What she writes about: Queens who ruled from the shadows. Scientists whose male colleagues took credit. Revolutionaries who risked everything. But also ordinary women – those who survived wars, raised families through upheaval, and shaped their communities in ways no one bothered to record.
Margot turns historical figures into real people. She writes with warmth and detail, making centuries-old stories feel surprisingly relevant. Rigorous research meets accessible storytelling – no dusty academic jargon, just compelling narratives backed by solid facts.
When she's not writing, you'll find her in regional archives, collecting oral histories, or visiting sites connected to the women she writes about.