Inventors Who Made Everyday Devices More Practical

The S-bend. Flushing toilets existed before him, but in 1775 the Scottish watchmaker Cumming patented a valve closet with a bend in the waste pipe that kept a pool of water standing in it, sealing out sewer smells. That small piece of plumbing, refined by Joseph Bramah and others, is what made indoor toilets bearable, and a water trap still sits under every sink and toilet today.

Bicycle wheels and the differential. A Coventry sewing-machine maker, Starley turned the city into the centre of the cycle trade. With William Hillman he built the Ariel high-wheeler in 1870, and in 1874 patented the tangent-spoked wheel, whose angled spokes carry driving and braking forces far better than radial ones and are still used today. His 1877 differential let a tricycle's two wheels turn at different speeds on corners.

The flat-bottomed paper bag. Paper bags of the 1860s were envelope-shaped and could not stand up. Knight, working at a Massachusetts paper bag company, designed a machine that cut, folded and glued square-bottomed bags automatically, and patented it in 1871 after winning a court case against a man who had copied her design. Grocery bags have been made on the same principle ever since.

The carbon-filament lamp. The Newcastle chemist Swan had worked on electric lamps for decades before better vacuum pumps let him demonstrate a working carbon-filament bulb in 1878 and 1879, independently of Thomas Edison. His lamps lit Cragside, the first house powered by hydroelectricity, and the Savoy Theatre. Rather than fight in court, the two men merged their British interests as Ediswan in 1883.

Longer-lasting lamp filaments. Early carbon filaments burned out quickly. Latimer, a self-taught draughtsman working for Hiram Maxim's lighting company, patented a better way of making carbon filaments in 1882, wrapping them in cardboard while they were baked so they did not crack. Cheaper, longer-lived bulbs followed. He later joined Edison's legal team as an expert on patents, and had earlier drawn the patent drawings for Alexander Graham Bell's telephone.

The reliable fountain pen. Fountain pens had existed for decades but blotted and flooded because ink and air could not swap evenly. Waterman, a New York insurance salesman, patented a feed in 1884 with fine channels that used capillary action to let air in as ink flowed out, giving a steady line. His company made it a mass-market tool, and modern feeds still work on the same idea.

The Rover safety bicycle. James Starley's nephew, working in Coventry, launched the Rover in 1885: two wheels of similar size, a chain driving the rear wheel, and the rider seated safely between them instead of perched over a giant front wheel. Others had tried chain drives, but the Rover's layout was so right that the diamond-framed bicycle has barely changed since. His company later built cars under the same name.

The dishwasher. Earlier washing machines for dishes splashed water about without cleaning much. Cochrane, an Illinois hostess tired of chipped china, designed wire racks shaped to hold each plate, cup and saucer while hot soapy water was pumped over them, and patented it in 1886. She founded a company to make them, selling first to hotels and restaurants, and its line eventually became part of KitchenAid.

The pneumatic tyre. In Belfast in 1888 the vet Dunlop made air-filled tyres for his son's tricycle to soften the jolts of cobbled streets, and they proved faster as well as more comfortable. His patent was later ruled invalid because Robert William Thomson had patented the idea in the 1840s, but Dunlop's version arrived just as the safety bicycle did, and the company formed around it made air tyres standard on bicycles and then cars.

Air conditioning by calculation. Asked in 1902 to stop paper swelling in a Brooklyn printing works, the young engineer Carrier designed a system that controlled humidity as well as temperature. His 1911 paper of psychrometric formulae let engineers calculate a cooling plant instead of guessing, which is what made air conditioning dependable enough for cinemas, offices and eventually homes. He co-founded the Carrier company in 1915.

The windscreen wiper. Riding a New York tram in 1902, Anderson watched the driver lean out to clear sleet from the glass. Her 1903 patent was for a rubber blade on a swinging arm worked by a lever inside the vehicle, cleaning the screen without opening it. Manufacturers turned her down and the patent lapsed, but wipers became standard within years, and Charlotte Bridgwood patented an automatic version in 1917.

The disposable razor blade. King Camp Gillette had the idea of a cheap, throwaway blade in the 1890s, but cutlers said thin steel could not be hardened and sharpened. Nickerson, an MIT-trained engineer, worked out how to do it and designed the machines to grind and hone blades in bulk, so Gillette's safety razor could go on sale in 1903. It is a clear case of the engineer making a salesman's idea work, while the razor carried the other man's name.

The paper coffee filter. In Dresden in 1908 Bentz, frustrated by bitter coffee full of grounds from cloth bags and percolators, punched holes in a brass pot and lined it with blotting paper from her son's exercise book. The paper held back grounds and could simply be thrown away. She patented the idea that year and founded Melitta with her husband, and the pour-over method it popularised is still widely used.

Stainless cutlery. Investigating gun barrels that wore out too quickly, the Sheffield metallurgist Brearley noticed in 1913 that a steel with a high chromium content refused to rust or be etched. He saw its use for knives, which until then stained and had to be scoured, and pushed local cutlers to adopt it. German and American metallurgists were working on similar steels at the same time, but Brearley's work made stainless kitchenware a Sheffield product.

The modern zip. Whitcomb Judson's hook-and-eye clasp of the 1890s jammed and sprang open. Sundback, a Swedish-born engineer at Judson's company, replaced the hooks in 1913 with rows of small interlocking teeth gripped together by a slider, and patented the separable fastener in 1917. Just as important, he designed the machine that could stamp out the teeth and attach them to tape cheaply enough for clothing.

The ballpoint pen. Ballpoints had been patented since the 1880s but leaked or skipped. Bíró, a Hungarian journalist, worked with his chemist brother György on a quick-drying, thicker ink and a ball-and-socket tip that fed it evenly, patenting the design in 1938 and refining it in Argentina. The RAF bought his pens because they wrote at altitude, and Marcel Bich's licensed version made them cheap enough to throw away.

The microwave oven. A largely self-taught engineer at Raytheon, Spencer had already found ways to mass-produce radar magnetrons in the Second World War when he noticed in 1945 that one had melted a sweet in his pocket. He and colleagues patented microwave cooking, and the first Radarange stood nearly six feet tall. It took Raytheon's purchase of Amana, and a countertop model in 1967, to put the idea into ordinary kitchens.

The waterproof nappy cover. Tired of soaked cloth nappies, bedding and clothes, Donovan cut up a shower curtain in 1946 and sewed a cover that kept moisture in, using snap fasteners rather than safety pins. She sold her Boater in a New York department store and patented it in 1951 before selling the rights. Manufacturers rejected her next idea, a disposable paper nappy, which others brought to market years later.

Correction fluid. Electric typewriters of the 1950s used carbon-film ribbons whose mistakes would not erase cleanly. Graham, a Dallas secretary who painted in her spare time, mixed white tempera paint to brush over her errors, refined the recipe in her kitchen and sold it as Mistake Out from 1956. As Liquid Paper it became a fixture of every office until word processing, and she sold the company to Gillette in 1979.

The Workmate. A former Lotus car designer, Hickman split a chair while sawing on it at home and designed a folding bench whose two halves of the top also worked as a vice. Several toolmakers rejected it, so he sold it himself until Black and Decker took a licence in 1972. Tens of millions have been sold, and he spent years defending his patents against copies.

The bright blue LED. Red and green LEDs had existed for years, but white light needed blue. Building on Isamu Akasaki and Hiroshi Amano's work on gallium nitride, Nakamura developed manufacturing methods at Nichia that produced a bright, efficient blue LED in 1993. With a phosphor coating it gave white LEDs, the cheap and long-lasting bulbs and screen backlights now everywhere. The three shared the 2014 Nobel Prize in Physics.

The bagless vacuum cleaner. Annoyed that his vacuum cleaner lost suction as its bag clogged, Dyson borrowed the cyclone separators used in sawmills and spent five years building 5,127 prototypes. British makers would not license it, so it first sold in Japan in 1986, and his own DC01 followed in 1993. Constant suction and a see-through bin changed what people expected of the machine, and cyclones are now standard.

The wind-up radio. After seeing a 1991 television report on the difficulty of spreading health information in parts of Africa where batteries were expensive and mains power scarce, Baylis built a radio powered by a hand-wound spring driving a small generator. Business partners Christopher Staines and Rory Stear set up the company that made it from 1995, and its engineers developed the production design. Baylis campaigned for inventors' rights until his death in 2018.