Born: 14 February 1838, United States
Died: 12 October 1914
Country most active: United States
Also known as: NA
The following is republished with permission from Women Engineers’ History and was written by Nina C. Baker.
Margaret Eloise Knight (14 February 1838 – 12 October 1914) is celebrated as one of the USA’s most prolific female inventors and patent holders. I stumbled across her story, arguably more than one story, whilst picking up on a research theme I hadn’t looked at for a while: women who designed cars or parts of cars. She seems to be best known for designing a machine to make flat-bottomed paper bags, for which she is an inductee in the National Inventors’ Hall of Fame.
However, I want to focus here more on her later inventions relating to motor cars and the company she set up with her niece and great-niece, Anna and Beatrice Davidson. Her wikipedia page gives the basics of her life but with little emphasis on her automobile work. A useful account is this article from Simply Saratoga (Holiday issue 2022, pp93-94), although embedded in a piece mainly about her business partners, her niece and great niece Anna and Beatrice Davidson.
Her childhood in Manchester, New Hampshire, was in very modest circumstances as her father died when she was young. Always of a practical nature, she was said to be happiest tinkering with bits of wood and metal, but the family was not able to afford to give her or her brothers much education and she followed them into the nearby factories. She noticed that there were accidents caused by the sharp ends of fast-moving shuttles and she is said to have invented some sort of safety device (at the age of 12) which was adopted by local textile mills but never patented. Her first formal invention arose out of her job at a paper factory, Columbia Paper Bag Co, where she devised and eventually patented the paper bag making machine which established her fame. In 1870, having won a court case against someone who tried to pinch her ideas, she set up her own company, Eastern Paper Bag Co.
Further patents followed relating to paper processing, shoe-making, clothing, rubber sheet winding and even window sashes (see full list below). But it wasn’t until the final 12 years of her life that her energetic mind turned to the new technology of the internal combustion engine and automobiles.
Between 1902 and 1915 (after her death) 6 patents were registered in her name or that of the K-D Motor Company, relating to rotary engines, 2 for internal combustion engines, and 1 each for a new sort of packing ring, a sprung wheel and an automatic machine for boring cylinders. The photo at the top of this blog shows that she was still experimenting and inventing right up to the end of her life and the car-related inventions were perhaps the culmination of a lifetime’s knowledge gained the hard way: by doing it. There was never the chance for her to get any formal engineering education but clearly she had become very knowledgeable as well as practical.
Margaret’s finances were never robust enough to develop her ideas to full fruition. Her own paper bag company struggled against male prejudice both within the works and in selling to the marketplace. It wasn’t until her niece, the wealthy widow Mrs Anna Flora Davidson, stepped in that she was able to have the resources to put her automobile ideas into reality. Margaret and Anna, with Anna’s daughter Beatrice, set up the Knight-Davidson Motor Company in 1896 with capital of US$100,000 and were eventually able to have a model of car made which implemented at least some of Margaret’s ideas.
It is not completely clear which of her engine patents was used in the “Silent Knight” cars she had built and exhibited at the 1912 Boston Automobile Show. In some places it is described as being a ‘valveless engine’, in others as having ‘sleeve valves‘. The image of the advertisement above mentions ‘crescent valves, which seem to be ‘two crescent shaped half sleeves in a double bored cylinder’. The advantage of the type of valves which Margaret was working on was that they ran much quieter than the usual poppet valves of the era. However, the unfamiliar is always a hard sell, especially in a novel technology which cars still were at that time. Setright commented “The sleeve valve is nowadays too little remembered, and in its time was too little respected… …It is worth pointing out that sleeve valves featured in the most powerful piston engine to fly… …All that can be said in argument may be summed up by the facts that Bristol ran one of their 64 inch sleeves up to 8000 rev/min in a single-cylinder test engine without anything going awry”[1]
At this point it is worth mentioning the unavoidable confusion between our heroine and a Mr Charles Yale Knight – also an American auto engine designer, who also invented sleeve valves and also dubbed at least one of his cars “Silent Knight”. A forum discussion about sleeve and crescent valves quotes Setright: “The Knight split sleeve-valve engine designed for the K-D car (Knight-Davidson) in 1913 (no connection with Charles Yale Knight’s double sleeve valve designs) by M.E. Knight, employed “scotch-yokes” but these were later replaced with conventional connecting rods and big ends.” [1]
The 90hp car was constructed for her by the president of the Society of Engineers, the Swiss-born automobile engineer, Charles G. Greuter, and the 5-seater body was built on its 3.48 metre base by Moore & Munger Co. From the photos of the car it seems that her patent internally-sprung wheels were not used, as the wheels seem to be the kind with thin spokes like a bicycle. The car was sold for the princely sum of US$6,000 (about US$200,000 today). Unsurprisingly perhaps, only a few were sold at this significant cost, despite its innovations and quiet running compared to the usual internal combustion engines generally on the market.
Margaret unfortunately died in 1914, and with her passing the K-D Motor Company lost its impetus and resident genius and was closed down. As World War 1 had already started in Europe it is likely that her tiny automobile company would not have survived – most of the other such small companies selling to the wealthy did not last long.
Her enduring legacy is probably not in her highly technical later inventions, but her first big success, the flat-bottomed paper bag you get your groceries in.
This biography is shared with permission from The Mills Archive Trust.
Margaret was born in York, Maine – one of a large family and was, according to historian Henri Petroski, known around town for making toys for her brothers, such as kites and sleds which she built by hand. Her father died when she was still a child which meant the family relocating to New Hampshire. Margaret had to start working long hours in a New Hampshire textile mill to help her mother make ends meet.
Mills were notoriously dangerous due to poor conditions and a lack of safety standards and Margaret, aged 12, witnessed a horrific accident when a shuttle broke loose and impaled a fellow worker. Within weeks she had devised a way to stop this all too common an occurrence happening again, inventing a shuttle restraint system that would become a standard fixture on looms across the country. Unfortunately, as a child she was not aware of the patent system and failed to register her invention, thus receiving no compensation for her efforts.
However, this device was only the first of many of her inventions. Margaret left the textile mill in her late teens, working her way through several jobs to help support her family. After the Civil War she found work in Massachusetts at the Columbia Paper Bag Company making bags by hand. It was here that she made her name inventing a paper bag machine, which could automatically cut, fold and glue flat-bottomed paper bags. Up to then bags were envelope-style, with the bottoms glued together in a v-shape which limited how much the bag would hold. These flat-bottomed bags transformed the industry. An updated version of her machine was still in use at the end of the 20th century.
Today these bags are found everywhere, from McDonalds to local market stalls! Of course, this revolutionised the paper bag industry by replacing the work of thirty people with one machine! The invention became used worldwide. Also, a side-effect was the fact that retailers quickly realised the value of being able to promote their goods by advertising on the side of the bags. Today, nearly two hundred years later, paper bags are coming back into fashion as they are more eco-friendly than the plastic bag.
Fully operational by 1868, this invention had drastically improved both the company’s output and the uniformity of the bags. Taking her previous experience into account. Margaret realised she had to apply for a patent. Unfortunately, one Charles Annan, a co-worker, tried to steal her design. This was taken to court, where he argued that she “could not possibly understand the mechanical complexities of the machine” – but Margaret then produced the original blueprints of the machine’s designs. She won her case.
Margaret now was in a position to co-found her own paper bag company in Hartford, Connecticut, called the Eastern Paper Bag Company. She never stopped innovating, and went on to patent more than 25 inventions, ranging from a sole-cutting machine for shoemaking to a compound rotary engine. When she died in 1914 she was honoured in a local obituary as a “woman Edison.”
In 2006 Margaret was inducted into the Paper Industry International Hall of Fame; by then over 7000 machines throughout the world were producing Margaret’s flat-bottomed bags, with major suppliers located in the US, Germany, France, and Japan.