Modern Washing Machine

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. In appearance and mechanical detail, this first machine was not unlike the front loading automatic washers produced today.

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 very expensive. For instance, the Bendix Home Laundry Service Manual (published November 1, 1946) shows that the drum speed change was facilitated by a 2-speed gearbox built to a heavy duty standard (not unlike a car automatic gearbox, albeit at a smaller size). The timer was also probably fairly costly, because miniature electric motors were 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 both the hot and cold water supplies became the norm, as dedicated laundry water hookups became common. Most modern front-loading European machines now only have a cold water connection (called “cold fill”) 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.

After the attack on Pearl Harbor, US domestic washer production was suspended for the duration of World War II in favor of manufacturing war material. However, numerous US appliance manufacturers were given permission 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 for the industry.

A large number of US manufacturers introduced competing automatic machines (mainly of the top-loading type) 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 (available from Hoover in the UK until at least the 1970s) included two tubs: one with an agitator or impeller for washing, plus another smaller tub for water extraction or centrifugal rinsing.

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 (for example, the drain pump motor). 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 it was possible for the user to 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 prior to 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 in 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 in 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 extremely expensive. During the 1960s, twin tub machines briefly became very popular, helped by the low price of the Rolls Razor washers. Some machines had the ability to 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.

Modern washers

Over time manufacturers of automatic washers have gone to great lengths to reduce cost. For instance, expensive gearboxes are no longer required, since motor speed can be controlled electronically. Some models can be controlled via WiFi, and have angled drums to facilitate loading. 

Even on some expensive washers, the outer drum of front loading machines is often (but not always) made of plastic (it can also be made out of metal but this is expensive). This makes changing the main bearings difficult, as the plastic drum usually cannot be separated into two halves to enable the inner drum to be removed to gain access to the bearing.

Some manufacturers have taken steps to reduce vibration emanating from their washers, by means of reducing or controlling motor speeds, using hydraulic suspensions instead of spring suspensions, and having freely moving steel balls (Samsung VRT) or liquid contained inside a ring mounted on both the front and back sides of the drum in order to counter the weight of the clothes and reduce vibration.

Some machines, since 1998 now use a direct drive motor, a low aspect ratio device, where the stator assembly is attached to the rear of the outer drum, whilst the co-axial rotor is mounted on the shaft of the inner drum. Direct drive eliminates the need for a pulley, belt and belt tensioner. It was invented by LG Electronics in 1998 and patents were granted in the US in 2010. Since, other manufacturers have followed suit. Some washing machines with this type of motor now come with 10 warranties. The direct drive motor’s rotor is outside the stator as this provides a slim motor with speed reduction and torque multiplication. The rotor is connected to the inner tub through its center. It can be made out of metal or plastic.

Today, faster load speeds are becoming a higher and higher demand. Some US companies are working on developing new spin technology to wash clothes faster and more efficiently. Lightning Clean is one of these companies. They are producing the first 10-minute washing machine.

Additional features

The modern washing machine market is burgeoning innovations and features. For example:

  • Some other washing machines include water jets (also known as water sprays and water showers) and steam nozzles that claim to sanitize clothes and help reduce washing times and remove soil from the clothes. Water jets get their water from the bottom of the drum, thus recirculating the water in the washer.
  • Others have special drums with holes that will fill with water from the bottom of the tub and redeposit the water on top of the clothes. Some drums have elements with the shape of waves, pyramids, hexagons or diamonds.
  • Some include titanium or ceramic heating elements that claim to eliminate calcium build up in the element. They can heat water up to 95 °C.
  • Some high end models have lights built into the washer itself to light up the drum.
  • Others have soap dispensers where the user just fills a tank with detergent and softener and the washing machine automatically doses the detergent and softener and sometimes picks the most appropriate wash cycle. In some models, the tanks come pre filled and are installed and replaced with new tanks, also pre filled or refilled by the user, in a dedicated compartment on the bottom of the machine. The Lightning One machine uses a pod cartridge to allow easy soap refills.
  • Some have support for single use capsules containing enough laundry additives for one load. The capsules are installed in the detergent compartment.
  • Many dilute the detergent before it comes in contact with the clothes, some by means of mixing the soap and water with air to make foam, which is then introduced into the drum.
  • Some have pulsators that are mounted on a plate on the bottom of the drum instead of an agitator. The plate spins, and the pulsators generate waves that help shake the soil out of the clothes. Many also include mechanisms to prevent or remove undissolved detergent residue on the detergent dispenser.
  • Some manufacturers like LG Electronics and Samsung Electronics have introduced functions on their washers that allow users to troubleshoot common problems with their washers without having to contact technical support. LG’s approach involves a phone receiving signals through sound tones, while Samsung’s approach involves having the user take a photo of the washer’s time display with his or her phone. In both methods, the problem and steps to resolve it are displayed on the phone itself. Some models are also NFC enabled. Some implementations are patented under US Patent US20050268669A1 and US Patent US20050097927A1.
  • In 1992 Glenn Isbister introduced Miele in Kanananskis Alberta. This started a laundry revolution Canada. As Canadians started to buy front load washers vs top load.

In the early 1990s, upmarket machines incorporated microcontrollers for the timing process. These proved reliable and cost-effective, so many cheaper machines now also incorporate microcontrollers rather than electromechanical timers. Since the 2010s, some machines have touchscreen displays, full color or color displays, or touch sensitive control panels.

In 1994, Staber Industries released the System 2000 washing machine, which is the only top-loading, horizontal-axis washer to be manufactured in the United States. The hexagonal tub spins like a front-loading machine, using only about one third as much water as conventional top-loaders. This factor has led to an Energy Star rating for its high efficiency. This type of horizontal axis washer and dryer (with a circular drum) is often used in Europe, where space is limited, as they can be as thin as 40 cm in width.

In 1998, New Zealand-based company Fisher & Paykel introduced its SmartDrive washing machine line in the US. This washing machine uses a computer-controlled system to determine certain factors such as load size and automatically adjusts the wash cycle to match. It also used a mixed system of washing, first with the “Eco-Active” wash, using a low level of recirculated water being sprayed on the load followed by a more traditional style wash. The SmartDrive also included direct drive brushless DC electric motor, which simplified the bowl and agitator drive by doing away with the need for a gearbox system.

In 2000, the British inventor James Dyson launched the CR01 ContraRotator, a type of washing machine with two cylinders rotating in opposite directions. It was claimed that this design reduced the wash time and produced cleaner washing than a single cylinder machine. In 2004 there was the launch of the CR02, which was the first washing machine to gain the British Allergy Foundation Seal of Approval. However, neither of the ContraRotator machines are now in production as they were too expensive to manufacture. They were discontinued in 2005. It is patented under U.S. Patent US7750531B2U.S. Patent US6311527U.S. Patent US20010023513U.S. Patent US6311527B1U.S. Patent USD450164.

In 2001, Whirlpool Corporation introduced the Calypso, the first vertical-axis high efficiency washing machine to be top-loading. A washplate in the bottom of the tub nutated (a special wobbling motion) to bounce, shake, and toss the laundry around. Simultaneously, water containing detergent was sprayed on to the laundry. The machine proved to be good at cleaning, but gained a bad reputation due to frequent breakdowns and destruction of laundry. The washer was recalled with a class-action lawsuit and pulled off the market.

In 2003, Maytag introduced their top-loading Neptune washer. Instead of an agitator, the machine had two washplates, perpendicular to each other and at a 45 degree angle from the bottom of the tub. The machine would fill with only a small amount of water and the two washplates would spin, tumbling the load within it, mimicking the action of a front-loading washer in a vertical axis design.

In 2006, Sanyo introduced the “world-first” (as of February 2, 2006, with regards to home use drum-type washer/dryer) drum type washing machine with “Air Wash” function (i.e.: using ozone as disinfectant). It also reused and disinfected rinse water. This washing machine uses only 50 L (11.0 imp gal; 13.2 US gal) of water in the recycle mode.

Approximately in 2012, eco indicators were introduced, capable of predicting the energy demand based on the customer settings in terms of program and temperature.

Features available in most modern consumer washing machines:

  • Delayed execution: a timer to delay the start of the laundry cycle
  • Predefined programs for different laundry types
  • Rotation speed settings
  • Variable temperatures, including cold wash

Additionally some of the modern machines feature:

  • Child lock
  • Steam
  • Time remaining indication

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