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Awindscreen wiper (Commonwealth English) orwindshield wiper (American English) is a device used to remove rain, snow, ice, washer fluid, water, or other debris from avehicle's front window. Almost allmotor vehicles, includingcars,trucks,buses,trainlocomotives, andwatercraft with acabin—and someaircraft—are equipped with one or more such wipers, which are usually a legal requirement.
A wiper generally consists of a metal arm; one endpivots, and the other end has a long rubber blade attached to it. The arm is powered by amotor, often anelectric motor, althoughpneumatic power is also used for some vehicles. The blade is swung back and forth over the glass, pushing water, otherprecipitation, or any other impediments to visibility from its surface. The speed is usually adjustable on vehicles made after 1969, with several continuous rates and often one or moreintermittent settings. Most personal automobiles use two synchronizedradial-type arms, while many commercial vehicles use one or morepantograph arms.
On some vehicles, awindscreen washer system is also used to improve and expand the function of the wiper(s) to dry or icy conditions. This system sprays water, or anantifreezewindow washer fluid, at the windscreen using several well-positionednozzles. This system helps remove dirt or dust from the windscreen when used in concert with the wiper blades. When antifreeze washer fluid is used, it can help the wipers remove snow or ice. For these types of winter conditions, some vehicles have additionalheaters aimed at the windows, embeddedheating wire(s) in the glass, or embeddedheating wire(s) in the wiper blade; thesedefroster systems can melt ice or help to keep snow and ice from building up on the windscreen. Less frequently, miniature wipers are installed onheadlights to ensure they function optimally.
One of the earliest recorded patents for the windscreen wiper is byGeorge J. Capewell of Hartford Connecticut, which was filed on August 6, 1896.[1] His invention was for "windows of slow-moving craft; but it is more particularly adapted and intended for windows of rapidly-moving vehicles, such as high-speed locomotives and cars, with which it is necessary that the observer or driver should have a clear view of the path or track." Similar to current automotive wiper designs, his invention involves "usually two of these wipers, and they can be secured to the frame below the front board of the vehicle or behind the housing surrounding the window in position to be out of sight and in such manner that one will scrape off the heaviest part of the substance collected upon the glass." His patent illustration shows a circular window, although the patent notes "it is not essential that the glass be circular in form."
Other early designs for the windscreen wiper are credited to Polish concertpianistJózef Hofmann,[2] and to Mills Munitions,Birmingham, who also claimed to have been the first to patent windscreen wipers in England.At least three inventors patented windscreen cleaning devices at around the same time in 1903;Mary Anderson, Robert Douglass, and John Apjohn. In April 1911, a patent for windscreen wipers was registered by Sloan & Lloyd Barnes, patent agents of Liverpool, England, forGladstone Adams ofWhitley Bay.
American inventorMary Anderson is popularly credited with devising the first operational windscreen wiper in 1903.[3][4] In Anderson's patent, she called her invention a "window cleaning device" for electric cars and other vehicles. Operated via a lever from inside a vehicle, her version of windscreen wipers closely resembles the windscreen wiper found on many early car models. Anderson had a model of her design manufactured, then filed a patent (US 743,801) on June 18, 1903 that was issued to her by the US Patent Office on November 10, 1903.[5][6]
Irish born inventor James Henry Apjohn (1845–1914) patented an "Apparatus for Cleaning Carriage, Motor Car and other Windows" which was stated to use either brushes or wipers and could be either motor driven or hand driven. The brushes or wipers were intended to clean either both up and down or in just one direction on a vertical window. Apjohn's invention had a priority date in the UK of 9 October 1903.[8]
John R. Oishei (1886-1968) formed the Tri-Continental Corporation in 1917. This company introduced the first windscreen wiper, Rain Rubber, for the slotted, two-piece windscreens found on many of the automobiles of the time. TodayTrico Products is one of the world's largest manufacturers of windscreen wipers.[citation needed]Bosch has the world's biggest windscreen wiper factory inTienen, Belgium, which produces 350,000 wiper blades every day.[9] The first automatic electric wiper arms were patented in 1917 by Charlotte Bridgwood.[10]
Inventor William M. Folberth and his brother, Fred, applied for a patent for an automatic windscreen wiper apparatus in 1919, which was granted in 1921.[11] It was the first automatic mechanism to be developed by an American, but the original invention is attributed by others to Hawaiian, Ormand Wall.[11] Trico later settled a patent dispute with Folberth and purchased Folberth's Cleveland company, the Folberth Auto Specialty Co. The new vacuum-powered system quickly became standard equipment on automobiles, and the vacuum principle was in use until about 1960. In the late 1950s, a feature common on modern vehicles first appeared, operating the wipers automatically for two or three passes when the windscreen washer button was pressed, making it unnecessary to manually turn the wipers on as well. Today, an electronic timer is used, but originally a small vacuum cylinder mechanically linked to a switch provided the delay as the vacuum leaked off.
Theinventor of intermittent wipers (non-continuous, now including variable-rate wipers) might have been Raymond Anderson, who, in 1923, proposed anelectro-mechanical design. (US Patent 1,588,399). In 1958, Oishei et al. filed apatent application describing not only electro-mechanical, but alsothermal andhydraulic designs. (US Patent 2,987,747). Then, in 1961, John Amos, an engineer for the UKautomotive engineering companyLucas Industries, filed the first patent application in the UK for asolid-state electronic design. (US patent 3,262,042).
In 1963, another form of intermittent wiper was invented byRobert Kearns, anengineering professor atWayne State University inDetroit, Michigan.[3] (United States Patent 3,351,836 – 1964 filing date). Kearns's design was intended to mimic the function of thehuman eye, whichblinks only once every few seconds. In 1963, Kearns built his first intermittent wiper system using off-the-shelf electronic components. The interval between wipes was determined by therate of current flow into a capacitor; when the charge in thecapacitor reached a certainvoltage, the capacitor would be discharged, activating one cycle of the wiper motor, and then repeating the process. Kearns showed his wiper design to theFord Motor Company and proposed that they manufacture the design. Fordexecutives rejected Kearns' proposal at the time, but later offered a similar design as an option on the company'sMercury line, beginning with the 1969 models.[3] Kearns sued Ford in a multi-yearpatent dispute that Kearns eventually won in court,[12] inspiring the2008 feature filmFlash of Genius based on a 1993New Yorker article that covered the legal battle.
In March 1970, French automotive manufacturerCitroën introduced more advancedrain-sensitive intermittent windscreen wipers on itsSM model. When the intermittent function was selected, the wiper would make one sweep. If the windscreen was relatively dry, the wiper motor drew highcurrent, which would set the controlcircuit timer to a long delay for the next wipe. If the motor drew little current, it indicated that the glass was still wet, and would set the timer to minimize the delay.
Wipers may be powered by a variety of means, although most in use today are powered by anelectric motor through a series of mechanical components, typically two4-bar linkages in series orparallel.
Vehicles with air-operated brakes sometimes usepneumatic wipers, powered by tapping a small amount of pressurized air from the brake system to a small air operated motor mounted on or just above the windscreen. These wipers are activated by opening a valve which allows pressurized air to enter the motor.
Early wipers were often driven by avacuum motor powered bymanifold vacuum. This had the drawback that manifold vacuum varies depending onthrottle position, and is almost non-existent under wide-open throttle, when the wipers would slow down or even stop. That problem was overcome somewhat by using a combined fuel/vacuum booster pump.
Some cars, mostly from the 1960s and 1970s, had variable-speed, hydraulically-driven wipers, most notably the '61–'69Lincoln Continental,[13] '69–'71Lincoln Continental Mark III (but not all '70 models),[14] and '63–'71Ford Thunderbird.[15] These were powered by the same hydraulic pump also used for the power steering mechanism.
On the earlierCitroën 2CV, the windscreen wipers were powered by a purely mechanical system, a cable connected to the transmission; to reduce cost, this cable also powered the speedometer. The wipers' speed was therefore variable with car speed. When the car was stationary, the wipers were not powered, but a handle under the speedometer allowed the driver to power them by hand.[citation needed]
Most early wipers used a rubber blade attached to a flat metal base. But as aerodynamic and styling concerns introduced curved windshields, these proved insufficient. In 1945, John W. Anderson, founder of Trico rival Anco, filed a patent for a wiper with branched arms to keep the blade pressed uniformly against both curved and flat glass,[16] adaptable to almost any windscreen curvature.[17] As curved windshields became more popular and widespread, following the debut of the 1947 Studebaker Starlight Coupe,[18] these soon became standard equipment. While they have been superseded by "beam-type" wipers with bodies made of flexible material, this type still remains the most popular.
Wiper blades are made ofnatural rubber,EPDM rubber (orethylene propylene rubber)[19] or a combination of both, as natural rubber performs better in cold weather but EPDM rubber doesn't "set" and resists better to thermal aging,UV, ozone and tearing.[20] Some manufacturers coat them withgraphite.[20]
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Most wipers are of the pivot (or radial) type: they are attached to a single arm, which in turn is attached to the motor. These are commonly found on many cars, trucks, trains, boats, airplanes, etc.
Modern windscreen wipers usually move in parallel (Fig. 1, below). However, variousMercedes-Benz models and other cars such as theVolkswagen Sharan employ wipers configured to move in opposite directions (Fig. 2), which is mechanically more complex but can avoid leaving a large unwiped corner of the windscreen in front of the front-seat passenger. A cost benefit to the auto-maker occurs when wipers configured to move in opposite directions do not need to be repositioned for cars exported toright hand drive countries such as the UK and Japan.
Another wiper design (Fig. 6) is pantograph-based, used on many commercial vehicles, especially buses with large windscreens. Pantograph wipers feature two arms for each blade, with the blade assembly itself supported on a horizontal bar connecting the two arms. One of the arms is attached to the motor, while the other is on an idle pivot.[citation needed] The pantograph mechanism, while being more complex, allows the blade to cover more of the windscreen on each wipe. However, it also usually requires the wiper to be "parked" in the middle of the windscreen, where it may partially obstruct the driver's view when not in use. A few models of automobile sometimes employ a pantograph arm on the driver's side and a normal arm for the passenger. The Triumph Stag, Lexus and several US makes employ this method to cover more glass area where the windscreen is quite wide but also very shallow. The reduced height of the windscreen would need the use of short wiper arms which would not have the reach to the edge of the windscreen.
A simple single-blade setup with a center pivot (Fig. 4) is commonly used on rear windscreens, as well as on the front of some cars.Mercedes-Benz pioneered a system (Fig. 5) called the "Monoblade", based oncantilevers, in which a single arm extends outward to reach the top corners of the windscreen, and pulls in at the ends and middle of the stroke, sweeping out a somewhat M-shaped path. This way, a single blade is able to cover more of the windscreen, displacing any residual streaks away from the centre of the windscreen.
Some larger cars in the late '70s and early '80s, especiallyLH driver American cars[citation needed], had a pantograph wiper on the driver's side, with a conventional pivot on the passenger side. Asymmetric wiper arrangements are usually configured to clear more windscreen area on the driver's side, and so are mostly mirrored for left and right-hand-drive vehicles (for example, Fig. 1 vs. Fig 10). One exception is found on the second generations of theRenault Clio,Twingo andScénic as well asBMW'sE60 5 Series andE63 6 Series, thePeugeot 206 and theNissan Almera Tino, where the wipers always sweep towards the left. On right-hand-drive models, a linkage allows the right-hand wiper to move outwards towards the corner of the windscreen and clear more area.
![Fig. 2: Widely used alternative configuration suiting either LHD or RHD operation[a]](/mt/?noimg=&dark=on&url=https%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aScheibenwischer2.svg)
Some vehicles are fitted with wipers (with or without washers) on the back window as well. Rear-window wipers are typically found onhatchbacks,station wagons / estates,sport utility vehicles,minivans, and other vehicles with more vertically-oriented rear windows that tend to accumulate dust. First offered in the 1940s, they achieved widespread popularity in the 1970s after their introduction on the Porsche 911 in 1966 and the Volvo 145 in 1969.[21]
In the 1960s, as interest in auto safety grew, engineers began researching various headlamp cleaning systems. In late 1968, Chevrolet introduced high pressure fluid headlamp washers on a variety of their 1969 models. In 1970,Saab Automobile introducedheadlight wipers across their product range. These operated on a horizontal reciprocating mechanism, with a single motor. They were later superseded by a radial spindle action wiper mechanism, with individual motors on each headlamp. In 1972, headlamp cleaning systems became mandatory in Sweden.
Headlamp wipers have all but disappeared today with most modern designs relying solely on pressurized fluid spray to clean the headlights. This reduces manufacturing cost, minimizes aerodynamic drag, and complies with EU regulations limiting headlamp wiper use to glass-lensed units only (the majority of lenses today are made of plastic.)
Most windscreen wipers operate together with a windscreen washer; apump that supplies a mixture of water,alcohol, anddetergent (a blend calledwindscreen washer fluid) from a tank to the windscreen. The fluid is dispensed through smallnozzles mounted on thehood. Conventional nozzles are usually used, but some designs use afluidicoscillator to disperse the fluid more effectively.
In warmer climates, water may also work, but it can freeze in colder climates, damaging the pump. Although automobileantifreeze is chemically similar to windscreen wiper fluid, it should not be used because it can damage paint. The earliest documented idea for having a windscreen wiper unit hooked up to a windscreen washer fluid reservoir was in 1931, Richland Auto Parts Co, Mansfield, Ohio.[22][23] Uruguayan racecar driver and mechanicHéctor Suppici Sedes developed a windscreen washer in the late 1930s.[24]
Since 2012, nozzles are replaced on some cars (Tesla, Volvo XC60 2018-2021, Citroen C4 Cactus) by a system called AquaBlade, developed by the company Valeo. This system supplies the washing liquid directly from the spoiler element of the wiper blade. This system suppresses visual disturbances during driving and so reduces the reaction time of the driver in case of incident.[25]
Some larger cars are equipped withhidden wipers (ordepressed-park wipers). When wipers are switched off in standard non-hidden designs, a "parking" mechanism or circuit moves the wipers to the lower extreme of the wiped area near the bottom of the windscreen, but still in sight. For designs that hide the wipers, the windscreen extends below the rear edge of the bonnet. The wipers park themselves below the wiping range at the bottom of the windscreen, but out of sight. Late model vehicles that hide wiper blades under the windscreen need to be placed in a service position in order to lift the wiper blade from the windscreen using the wiper service position.
Some vehicles are now available with automatic or driver-programmable windscreen wipers that detect the presence and amount of rain using arain sensor. The sensor automatically adjusts the speed and frequency of the blades according to the amount of rain detected. These controls usually have a manual override.
Rain-sensing windscreen wipers appeared on various models in the late 20th century, one of the first being theCitroën SM. As of early 2006[update], rain-sensing wipers are optional or standard on allCadillacs and mostVolkswagens, and are available on many other mainstream manufacturers.
The rain-sensing wipers system currently employed by most car manufacturers today was originally invented and patented in 1978 by Australian, Raymond J. Noack, see U.S. Patents 4,355,271 and 5,796,106. The original system automatically operated the wipers, lights and windscreen washers.
A common alternative design used on ships, called aclear view screen, avoids the use of rubber wiper blades. A round portion of the windscreen has two layers, the outer one of which is spun at high speed to shed water.
High speed aircraft may usebleed air which uses compressed air from the turbine engine to remove water, rather than mechanical wipers, to save weight and drag.[citation needed] Effectiveness of this method also depends onwater-repellent glass treatments similar toRain-X.
Many jurisdictions have legal requirements that vehicles be equipped with windscreen wipers. Windscreen wipers may be a required safety item in autosafety inspections. Some US states have a "wipers on, lights on" rule for cars.[26][27]
In the 1999 television commercialSynchronicity for theVolkswagen Jetta automobile,[28] windscreen wipers were synchronized with events seen through the car windows, and with the song "Jung at Heart", which was commissioned for the advertising agencyArnold Worldwide and composed by Peter du Charme[29] under the name "Master Cylinder".[30]
