Windscreen wiper: Difference between revisions
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[[Image:2008-04-24 Windshield wiper parts.jpg|thumb|right|250px|A common windscreen wiper arm and blade]] |
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[[Image:Heckscheibenwischer kl.jpg|thumb|right|250px|Windscreen wiper on a parked car. In this common design, the force from the arm is distributed evenly with a series of linkages known as a [[Whippletree (mechanism)|whippletree]].]] |
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[[Image:Rotating windshield wiper.jpg|thumb|right|250px|A common design for a "wiper" (also called a [[clear view screen]]) on a ship. A round portion of the windscreen has two layers, the outer one of which is spun at high speed.]] |
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A '''windscreen wiper''' or '''windshield wiper''' is a device used to remove [[rain]] and debris from a [[windscreen|windscreen or windshield]]. Almost all [[motor vehicle]]s, including [[train]]s, [[aircraft]] and [[watercraft]], are equipped with such wipers, which are usually a legal requirement. |
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A wiper generally consists of an arm, pivoting at one end and with a long rubber blade attached to the other. The blade is swung back and forth over the glass, pushing water from its surface. The speed is normally adjustable, with several continuous speeds and often one or more "intermittent" settings. Most automobiles use two synchronized radial type arms, while many commercial vehicles use one or more [[pantograph]] arms. |
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== History == |
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In 1903, [[Mary Anderson (inventor)|Mary Anderson]] is credited with inventing the first operational windshield wiper.<ref>{{cite web|title=The Windshield Wiper|publisher=American Heritage|url=http://www.americanheritage.com/events/articles/web/20070709-windshield-wiper-robert-kearns.shtml}}</ref><ref>{{cite web|title=Windshield Wipers|publisher=Massachusetts Institute of Technology|url=http://web.mit.edu/invent/iow/anderson.html}}</ref> 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 windshield wipers closely resembles the windshield wiper found on many early car models. Anderson had a model of her design manufactured. She then filed a patent (U.S. patent number 743,801) on June 18, 1903 that was issued to her by the U.S. Patent Office on November 10, 1903.<ref>{{cite web|title=Mary Anderson|publisher=Encyclopedia of Alabama|url=http://www.encyclopediaofalabama.org/face/Article.jsp?id=h-2553}}</ref><ref>{{cite web|title=Window-Cleaning Device|publisher=United States Patent and Trademark Office|url=http://www.google.com/patents?id=Zv5MAAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false}}</ref> |
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Irish born Inventor James Henry Apjohn (1845–1914) devised a method of moving two brushes up and down on a vertical plate glass windscreen in 1903. This was patented in the UK. |
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In April 1911, a [[patent]] for windscreen wipers was registered by Sloan & Lloyd Barnes, patent agents of Liverpool, England, for [[Gladstone Adams]] of [[Whitley Bay]]. The first designs for the windscreen wiper are also credited to concert [[pianist]] [[Józef Hofmann]], and Mills Munitions, [[Birmingham]] who also claimed to have been the first to patent windscreen wipers in England. |
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[[Image:Scheibenwischerverkauf in Apan fcm.jpg|thumb|left|225px|Street vendor of windscreen wipers in Mexico]] |
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The company Oishei formed, the Tri-Continental Corporation, introduced the first windshield wiper, Rain Rubber, for the slotted, two-piece windshields found on many of the automobiles of the time. Today Trico Products is one of the world's leading manufacturers of windshield wiping systems, windshield wiper blades and refills, with wiper plants on five continents. |
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Inventor William M. Folberth, in 1919, applied for a patent for an automatic windscreen wiper apparatus. The patent was granted in 1922. It was the first automatic mechanism. [[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 washer button was pressed, making it unnecessary to manually turn them 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. |
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In 1963, the first [[intermittent]] wipers were invented by [[Robert Kearns]], an engineering professor at Wayne State University in Detroit.<ref>{{cite web|title=The Windshield Wiper|publisher=American Heritage|url=http://www.americanheritage.com/events/articles/web/20070709-windshield-wiper-robert-kearns.shtml}}</ref> The road to intermittent wipers began on his wedding night earlier in 1953, when an errant champagne cork shot into Kearn's left eye, which eventually went almost completely blind. Nearly a decade later Kearns was driving his Ford Galaxie through a light rain, and the constant movement of the wiper blades irritated his already troubled vision. He got to thinking about the human eye, which has its own kind of wiper, the eyelid, that automatically closes and opens every few seconds. FInally in 1963, Kearns put his idea into action, building the first intermittent wiper system using off-the-shelf electronic components and offered it to Ford. The interval between wipes was determined by the rate of current flow into a capacitor. When the charge in the capacitor reached a certain voltage, the capacitor discharged, activating the wiper motor for one cycle. After extensive testing, Ford executives decided to offer Kearns’s intermittent wipers as an option on the company’s Mercury line beginning with the 1969 models.<ref>{{cite web|title=The Windshield Wiper|publisher=American Heritage|url=http://www.americanheritage.com/events/articles/web/20070709-windshield-wiper-robert-kearns.shtml}}</ref> Kearns may not, in fact, be the original inventor.{{Citation needed|date=February 2011}} John Amos, an engineer for the UK automative engineering company, [[Lucas Industries]] was the [[first to file]] a patent for an intermittent wiper. United States Patent #3,262,042 was filed two years before Kearns filed United States Patent #3,351,836, and was issued in 1966 before Kearns' patent was issued in 1967.<ref>{{cite web|title=ELECTRICAL OPERATING CIRCUITS FOR VEHICLE WINDSCREEN WIPERS|publisher=United States Patent and Trademark Office|url=http://www.google.com/patents?id=O11wAAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false}}</ref><ref>{{cite web|title=WINDSHIELD WIPERS|publisher=United States Patent and Trademark Office|url=http://www.google.com/patents?id=_qVQAAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false}}</ref> The difference is that the Amos patent describes an electromechanical device, whereas Kearns proposed a solid-state circuit. |
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In 1970, [[Saab Automobile]] introduced [[headlight]] wipers across the 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 March 1970, [[Citroën]] introduced rain-sensitive intermittent windscreen wipers on the SM model. When the intermittent function was selected, the wiper would make one swipe. If the windscreen was relatively dry, the wiper motor drew high current, which set the control circuit timer to delay the next wipe longest. If the motor drew little current, it indicated that the glass was wet, setting the timer to minimize the delay. |
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[[Robert Bosch GmbH|Bosch]] has the world's biggest windscreen wiper factory in [[Tienen]], [[Belgium]], which produces 350,000 wiper blades every day.<ref>[http://www.bosch.com.au/content/language1/html/715_5615.htm]</ref> |
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== Power == |
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Wipers may be powered by a variety of means, although most in existence today are powered by an [[electric motor]] through a series of mechanical components, typically two [[4-bar]] linkages in series or [[series and parallel circuits#Parallel circuits|parallel]]. Vehicles with air operated brakes sometimes use air operated wipers, run by bleeding a small amount of air pressure from the brake system to a small air operated motor mounted just above the windscreen. These wipers are activated by opening a valve which allows pressurized air to enter the motor. |
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Early wipers were often driven by a [[vacuum motor]] powered by [[manifold vacuum]]. This had the drawback that manifold vacuum alters depending on [[throttle]] position and is almost non-existent under wide-open throttle; the wipers would slow down or even stop. This problem was overcome somewhat by using a combined fuel/vacuum booster pump. Some cars, mostly from the 1960s and 1970s, had hydraulically driven wipers. On the earlier [[Citroën 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 waiting at a crossroad, the wipers were not powered, thus a handle under the speedometer allowed the driver to power them by hand. |
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== Geometry == |
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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. |
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Another type of wipers are the pantograph-based (see Fig. 6), which are 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|date=October 2010}} 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. |
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Some larger cars in the late '70s and early '80s, especially [[Right- and left-hand traffic#Driver seating position|LH driver]] American cars{{Citation needed|date=October 2010}}, had a pantograph wiper on the driver's side, with a conventional pivot on the passenger side. |
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[[Mercedes-Benz]] pioneered a system called the [[Monoblade]], based on [[cantilever]]s (see Fig. 5), 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 'W'-shaped path. This way, a single blade is able to cover more of the windscreen, and displace the residual streaks away from the center of the windscreen. |
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<gallery> |
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File:scheibenwischer1.svg| Fig. 1: most common geometry, found on vast majority of vehicles |
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File:scheibenwischer2.svg| Fig. 2: [[Mercedes-Benz W114]], [[Mercedes-Benz W168|W168]], [[Mercedes-Benz W169|W169]]; [[VW Sharan]], [[Honda Civic]], some [[minivans]], some [[school bus]]es, [[Peugeot 307]] |
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File:scheibenwischer9.svg| Fig. 3: [[SEAT Altea]], [[SEAT León]] Mk2, [[SEAT Toledo]] Mk3 |
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File:scheibenwischer3.svg| Fig. 4: [[VAZ-1111 Oka]], 1990's Citroën [[Citroen AX]] |
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File:scheibenwischer4.svg| Fig. 5: [[Subaru XT]], [[Mercedes-Benz W124]], [[Mercedes-Benz W201|W201]], [[Mercedes-Benz W202|W202]], [[Mercedes-Benz W210|W210]] |
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File:scheibenwischer5.svg| Fig. 6: [[Buses]], some [[school buses]], [[Mercedes-Benz O305]] |
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File:scheibenwischer8.svg| Fig. 7: [[MAN SE|MAN]], [[Toyota FJ Cruiser]], [[Jaguar E-type]], [[MG MGB|MGB]], [[MG Midget]], [[Austin Healey Sprite]], a 1968 US only ruling required a certain percentage of the windscreen to be wiped. |
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File:scheibenwischer7.svg| Fig. 8: obsolete, found on some older [[firetrucks]] |
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File:scheibenwischer6.svg| Fig. 9: US Military Wheeled Vehicles, some [[school bus]]es |
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File:scheibenwischer10.svg|Fig. 10: Like Fig. 1 but mirrored, [[Mercedes-Benz W140]] |
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</gallery> |
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== Other features == |
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Some larger cars are equipped with "hidden" (or "depressed-park") wipers. When wipers are switched off, 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. To hide the wipers, the windscreen extends below the rear edge of the hood, and the wipers park themselves below the wiping range at the bottom of the windscreen, but out of sight. |
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Some vehicles have small wipers or washers on the [[headlight]]s. In more modern vehicles, these have been replaced with a powerful jet spray, without wipers. Some vehicles are fitted with wipers (with or without washers) on the back window as well. Rear-window wipers are typically found on [[hatchback]]s, [[station wagons]], [[sport utility vehicle]]s, [[minivan]]s, and some [[sports car]]s. They were first implemented in the 1970s, but SUVs did not use them until the 1980s. |
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=== Windscreen washer === |
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{{See also|Windshield washer fluid}} |
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Most windscreen wipers operate together with a windscreen (or windshield) washer; a [[pump]] that supplies water and [[detergent]] (usually a blend called [[windshield washer fluid]]) from a tank to the windscreen through small [[nozzle]]s, mounted on the [[Hood (vehicle)|hood]] or on the wipers, known as a 'wet-arm' system. In warmer climates, water may also work, but it can freeze in colder climates. Although automobile antifreeze is chemically similar to [[windscreen wiper fluid]], it must not be used because it can damage paint. The earliest idea for having a windshield wiper unit hooked up to a windshield washer fluid reservoir was in 1931, Richland Auto Parts Co, Mansfield, Ohio <ref>[http://books.google.com/books?id=u-IDAAAAMBAJ&pg=PA248&dq=Popular+Mechanics+1931+curtiss&hl=en&ei=3bTyTKD7AZPfnQeEr635Cg&sa=X&oi=book_result&ct=result&resnum=3&ved=0CDAQ6AEwAg#v=onepage&q&f=true Windshield Freed Of Snow With Alcohol Wiper", February 1931, Popular Mechanics] article bottom half of page</ref> |
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=== Rain-sensing wipers === |
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Vehicles are now available with driver-programmable ''intelligent'' (automatic) windscreen wipers that detect the presence and amount of rain using a [[rain sensor]]. The sensor automatically adjusts the speed of the blades according to the amount of rain detected. These usually have a manual override. |
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Rain-sensing windscreen wipers appeared on various models in the late 20th century, one of the first being [[Nissan]]'s [[Nissan Silvia|200SX]]/[[Nissan Silvia|Silvia]]. {{As of|2006|alt=As of early 2006}}, rain-sensing wipers are optional or standard on all [[Cadillac]]s and most [[Volkswagen]], and are available on many other main-stream manufacturers. |
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== See also == |
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* [[Automobile ancillary power]] |
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* [[Lucas Automotive]] |
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== References == |
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{{reflist}} |
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== External links == |
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{{Commons category|Windshield wipers}} |
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* {{hsw|wiper|How Windshield Wipers Work}} |
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{{CarDesign nav}} |
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{{DEFAULTSORT:Windscreen Wiper}} |
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[[Category:Vehicle parts]] |
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[[Category:American inventions]] |
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[[ca:Eixugaparabrisa]] |
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[[cs:Stěrač]] |
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[[de:Scheibenwischer]] |
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[[es:Limpiaparabrisas]] |
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[[eo:Glacoviŝilo]] |
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[[fa:برفپاککن]] |
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[[fr:Essuie-glace]] |
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[[id:Penghapus kaca]] |
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[[it:Tergicristallo]] |
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[[nl:Ruitenwisser]] |
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[[ja:ワイパー]] |
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[[pl:Wycieraczka]] |
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[[pt:Limpador de para-brisa]] |
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[[ru:Стеклоочиститель]] |
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[[fi:Tuulilasinpyyhin]] |
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[[sv:Vindrutetorkare]] |
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[[vi:Hệ thống gạt nước và rửa kính]] |
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[[zh:雨刷]] |
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