Washing machine
A washing machine is a machine designed to launder clothing. The term is mostly applied to machines that use water. Other ways of doing laundry include dry cleaning and ultrasonic cleaning.
Modern-day home appliances use electric power to automatically clean clothes. The user adds laundry detergent, which is sold in liquid, powder, or dehydrated sheet form, to the wash water. The machines are also found in commercial laundromats where customers pay-per-use.
History
Washing by hand
Laundering by hand involves soaking, beating, scrubbing, and rinsing dirty textiles. Before indoor plumbing, it was necessary to carry all the water used for washing, boiling, and rinsing the laundry from a pump, well, or spring. Water for the laundry would be carried, heated on a fire for washing, and then poured into a tub. This meant the amount of warm, soapy water was limited; it would be reused to wash the least soiled clothing, then to wash progressively dirtier laundry.Removal of soap and water from the clothing after washing was a separate process. First, soap would be rinsed out with clear water. After rinsing, the soaking wet clothing would be formed into a roll and twisted by hand to extract water. The entire process often occupied an entire day of work, plus drying and ironing.
Early machines
An early example of washing by machine is the practice of fulling. In a fulling mill, the cloth was beaten with wooden hammers, known as fulling stocks or fulling hammers.The first English patent under the category of washing machines was issued in 1691. A drawing of an early washing machine appeared in the January 1752 issue of The Gentleman's Magazine, a British publication. Jacob Christian Schäffer's washing machine design was published in 1767 in Germany. In 1782, Henry Sidgier was issued a British patent for a rotating drum washer, and in the 1790s, Edward Beetham sold numerous "patent washing mills" in England.
One of the first innovations in washing machine technology was the use of enclosed containers or basins that had grooves, fingers, or paddles to help with the scrubbing and rubbing of the clothes. The person using the washer would use a stick to press and rotate the clothes along the textured sides of the basin or container, agitating the clothes to remove dirt and mud. This crude agitator technology was hand-powered, but still more effective than actually hand-washing the clothes.
More advancements were made to washing machine technology in the form of the rotating drum design. These early design patents consisted of a drum washer that was hand-cranked to make the wooden drums rotate. While the technology was simple enough, it was a milestone in the history of washing machines, as it introduced the idea of "powered" washing drums. As metal drums started to replace the traditional wooden drums, it allowed for the drum to turn above an open fire or an enclosed fire chamber, raising the water temperature for more effective washes.
It was in the nineteenth century that steam power was first used in washing machine designs.
In 1862, a patented "compound rotary washing machine, with rollers for wringing or mangling" by Richard Lansdale of Pendleton, Manchester, was shown at the 1862 London Exhibition.
The first United States Patent, titled "Clothes Washing", was granted to Nathaniel Briggs of New Hampshire in 1797. Because of the Patent Office fire in 1836, no description of the device survives. The invention of the washing machine is also attributed to Watervliet Shaker Village, as a patent was issued to an Amos Larcom of Watervliet, New York, in 1829, but it is not certain that Larcom was a Shaker. A device that combined a washing machine with a wringer mechanism appeared in 1843 when Canadian John E. Turnbull of Saint John, New Brunswick patented a "Clothes Washer With Wringer Rolls". During the 1850s, Nicholas Bennett of the Mount Lebanon Shaker Society at New Lebanon, New York, invented a "wash mill", but in 1858 he assigned the patent to David Parker of the Canterbury Shaker Village, where it was registered as the "Improved Washing Machine".
File:Electric Rotor Washer.JPG|thumb|left|upright|A 1923 electric Miele washing machine with a built-in mangle for drying
Margaret Colvin improved the Triumph Rotary Washer, which was exhibited in the Women's Pavilion at the Centennial International Exhibition of 1876 in Philadelphia. At the same exhibition, the Shakers won a gold medal for their machine.
Electric washing machines were advertised and discussed in newspapers as early as 1904. Alva J. Fisher has been incorrectly credited with the invention of the electric washer. The US Patent Office shows at least one patent issued before Fisher's US patent number 966677. The first inventor of the electric washing machine remains unknown.
US electric washing machine sales reached 800,000 units in 1928. However, high unemployment rates in the Depression years reduced sales; by 1932 the number of units shipped was down to about 600,000.
England established public washrooms for laundry along with bathhouses throughout the nineteenth century. The term "laundromat" can be found in newspapers as early as 1884, and they were widespread by the time of the Depression. Patrons used coin-in-the-slot facilities to rent washing machines.
Washer design improved during the 1930s. The mechanism was now enclosed within a cabinet, and more attention was paid to electrical and mechanical safety. Spin dryers were introduced to replace the dangerous power mangle/wringers of the day.
By 1940, 60% of the 25,000,000 electrically wired homes in the United States had an electric washing machine. Many of these machines featured a power wringer, although built-in spin dryers were not uncommon.
Automatic machines
Bendix Home Appliances, a subsidiary of Avco, introduced the first domestic automatic washing machine in 1937, having applied for a patent in the same year. Avco had licensed the name from Bendix Corporation, an otherwise unrelated company. This first machine resembled modern front-loading automatic washers in both appearance and mechanical design.Although it included many of today's basic features, the machine lacked any drum suspension and therefore had to be anchored to the floor to prevent "walking". Because of the components required, the machine was also expensive. For instance, the Bendix Home Laundry Service Manual shows that the drum speed change was facilitated by a two-speed gearbox built to a heavy-duty standard, like a smaller version of a car's automatic gearbox. The miniature electric motors used in the timers were also expensive to produce.
Early automatic washing machines were usually connected to a water supply via temporary slip-on connectors to sink taps. Later, permanent connections to hot and cold water became the norm. Most modern front-loading European machines now only have a cold water connection and rely completely on internal electric heaters to raise the water temperature.
Many of the early automatic machines had coin-in-the-slot facilities and were installed in the basement laundry rooms of apartment houses.
World War II and after
After the attack on Pearl Harbor, US domestic washer production was suspended for the duration of World War II in favor of manufacturing war materiel. However, numerous US appliance manufacturers were permitted to undertake the research and development of washers during the war years. Many took the opportunity to develop automatic machines, realizing that these represented the future of the industry.A large number of US manufacturers introduced competing automatic machines in the late 1940s and early 1950s. General Electric also introduced its first top-loading automatic model in 1947. This machine had many of the features that are incorporated into modern machines. Another early form of automatic washing machine manufactured by The Hoover Company used cartridges to program different wash cycles. This system, called the "Keymatic", used plastic cartridges with key-like slots and ridges around the edges. The cartridge was inserted into a slot on the machine and a mechanical reader operated the machine accordingly.
Several manufacturers produced semi-automatic machines, requiring the user to intervene at one or two points in the wash cycle. A common semi-automatic type included two tubs: one with an agitator or impeller for washing, plus another smaller tub for water extraction or centrifugal rinsing. These machines, as well as other older designs like the manual rotating drum, are still available, but are typically only used in circumstances where a standard water and power hookup for a washing machine is unavailable. Many are marketed for camping due to their light weight and ability to function without a water connection.
Since their introduction, automatic washing machines have relied on electromechanical timers to sequence the washing and extraction process. Electromechanical timers consist of a series of cams on a common shaft driven by a small electric motor via a reduction gearbox. At the appropriate time in the wash cycle, each cam actuates a switch to engage or disengage a particular part of the machinery. One of the first was invented in 1957 by Winston L. Shelton and Gresham N. Jennings, then both General Electric engineers. The device was granted US Patent 2870278.
On the early electromechanical timers, the motor ran at a constant speed throughout the wash cycle, although the user could truncate parts of the program by manually advancing the control dial. However, by the 1950s demand for greater flexibility in the wash cycle led to the introduction of more sophisticated electrical timers to supplement the electromechanical timer. These newer timers enabled greater variation in functions such as the wash time. With this arrangement, the electric timer motor is periodically switched off to permit the clothing to soak and is only re-energized just before a micro-switch being engaged or disengaged for the next stage of the process. Fully electronic timers did not become widespread until decades later.
Despite the high cost of automatic washers, manufacturers had difficulty meeting the demand. Although there were material shortages during the Korean War, by 1953 automatic washing machine sales in the US exceeded those of wringer-type electric machines.
In the UK and most of Europe, electric washing machines did not become popular until the 1950s. This was largely because of the economic impact of World War II on the consumer market, which did not properly recover until the late 1950s. The early electric washers were single-tub wringer-type machines, as fully automatic washing machines were expensive.
During the 1960s, twin tub machines briefly became popular, helped by the low price of the Rolls Razor washers. Twin tub washing machines have two tubs, one larger than the other. The smaller tub in reality is a spinning drum for centrifugal drying while the larger tub only has an agitator in its bottom. Some machines could pump used wash water into a separate tub for temporary storage and to later pump it back for re-use. This was done not to save water or soap, but because heated water was expensive and time-consuming to produce. Automatic washing machines did not become dominant in the UK until well into the 1970s and by then were almost exclusively of the front-loader design.
In early automatic washing machines, any changes in impeller/drum speed were achieved by mechanical means or by a rheostat on the motor power supply. However, since the 1970s electronic control of motor speed has become a common feature on the more expensive models.