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Escalators at Canary Wharf, London.
An escalator is a conveyor transport device for transporting people, consisting of individual, linked steps that move up or down on tracks, which keep the treads horizontal.
As a power-driven, continuous moving stairway designed to transport passengers up and down short vertical distances, escalators are used around the world to move pedestrian traffic in places where elevators would be impractical. Principal areas of usage include department stores, shopping malls, airports, transit systems, convention centers, hotels, and public buildings.
The benefits of escalators are many. They have the capacity to move large numbers of people, and they can be placed in the same physical space as one might install a staircase. They have no waiting interval (except during very heavy traffic), they can be used to guide people toward main exits or special exhibits, and they may be weather-proofed for outdoor use.
As recently as 2004, it was estimated that the United States had more than 30,000 escalators, and that 90 billion riders traveled on escalators each year.House of Representatives Resolution 4995, 22 July 2004: http://thomas.loc.gov/home/gpoxmlc108/h4995_ih.xml
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Escalators and their "cousins," moving walkways, are powered by constant-speed alternating current motors and move at approximately 1–2 feet (0.3–0.6 m) per second. The maximum angle of inclination of an escalator to the horizontal floor level is 30 degrees with a standard rise up to about 60 feet (18 m).
Modern escalators have single-piece aluminum or steel steps that moves on a system of tracks in a continuous loop. Escalators are typically used in pairs with one going up and the other going down, however in some places - especially European stores and metro stations - there are no escalators going down, the escalators only go up. Some modern escalators have transparent side panels that reveal their gearings.
Escalators are required to have moving handrails that keep pace with the movement of the steps. The direction of movement (up or down) can be permanently the same, or be controlled by personnel according to the time of day, or automatically be controlled by whoever arrives first, whether at the bottom or at the top (the system is programmed so that the direction is not reversed while a passenger is on the escalator).
A number of factors affect escalator design, including physical requirements, location, traffic patterns, safety considerations, and aesthetic preferences. Foremost, physical factors like the vertical and horizontal distance to be spanned must be considered. These factors will determine the pitch of the escalator and its actual length. The ability of the building infrastructure to support the heavy components is also a critical physical concern. Location is important because escalators should be situated where they can be easily seen by the general public. In department stores, customers should be able to view the merchandise easily. Furthermore, up and down escalator traffic should be physically separated and should not lead into confined spaces.
Traffic patterns must also be anticipated in escalator design. In some buildings, the objective is simply to move people from one floor to another, but in others there may be a more specific requirement, such as funneling visitors towards a main exit or exhibit. The number of passengers is important because escalators are designed to carry a certain maximum number of people. For example, a single-width escalator traveling at about 1.5 feet (0.45 m) per second can move an estimated 170 persons per five-minute period. The carrying capacity of an escalator system must match the expected peak traffic demand, presuming that passengers ride single-file. This is crucial for applications in which there are sudden increases in the number of riders. For example, escalators used in train stations must be designed to cater for the peak traffic flow discharged from a train, without causing excessive bunching at the escalator entrance.
In this regard, escalators help in controlling traffic flow of people. For example, an escalator to an exit effectively discourages most people from using it as an entrance, and may reduce security concerns. Similarly, escalators often are used as the exit of airport security checkpoints. Such an exit would generally be staffed to prevent its use as an entrance, as well.
It is preferred that staircases be located adjacent to the escalator if the escalator is the primary means of transport between floors. It may also be necessary to provide an elevator lift adjacent to an escalator for wheelchairs and disabled persons. Finally, consideration should be given to the aesthetics of the escalator. The architects and designers can choose from a wide range of styles and colors for the handrails and balustrades.
| Standard escalator step widths | ||||
|---|---|---|---|---|
| Size | Width (Between Balustrade Panels), in Millimeters | Width (Between Balustrade Panels), in Inches | Single-step capacity | Applications |
| Very small | 400 mm | 16 in | One passenger, with feet together | An older design, extremely rare today |
| Small | 600 mm | 24 in | One passenger | Low-volume sites, uppermost levels of department stores, when space is limited |
| Medium | 800 mm | 32 in | One passenger + one package or one piece of luggage. | Shopping malls, department stores, smaller airports |
| Large | 1000 mm | 40 in | Two passengers — one may walk past another | Mainstay of metro systems, larger airports, train stations, some retail usage |
An escalator user may choose to stand and ride at the speed of the escalator, or walk in the same direction to arrive faster. In many places — particularly on the longer escalators, used daily by commuters, found on rapid transit systems — passengers who stand customarily stay on one particular side of the escalator, leaving the other side free for walkers. The proper side for walking does not necessarily correspond with the passing lane in road traffic: passengers stand on the right and walk on the left on the London Underground as well as the Washington, Boston, Hong Kong, Seoul, Paris and Moscow subway systems; but in Singapore, Australia and New Zealand, they stand on the left. In Japan, Tokyo riders stand on the left but Osaka riders stand on the right. On the Montreal Metro, while walking on escalators is theoretically forbidden, this rule is scarcely observed and not at all enforced, and passengers tend to stand on the right. In some countries there is no convention and people stand on either side randomly as they please.
A mnemonic for the U.S./British standing-and-walking convention is that stand and right each have five letters, while walk and left have four.
Safety is also major concern in escalator design. Fire protection of an escalator floor-opening may be provided by adding automatic sprinklers or fireproof shutters to the opening, or by installing the escalator in an enclosed fire-protected hall. To limit the danger of overheating, adequate ventilation for the spaces that contain the motors and gears must be provided.
There have been various reports of people actually falling off a moving escalator or getting one’s shoe stuck in part of the escalator; shoe laces are a particular hazard when untied and/or loose. A few fatal accidents in the recent past are:
In the 1930s, at least one suit was filed against a department store, alleging that its escalators posed an attractive nuisance, responsible for a child’s injury.”Negligence: Escalator Not an Attractive Nuisance,” Michigan Law Review, Vol. 38, No. 2 (Dec. 1939): 265 – 267. These cases were almost always dismissed. Moreover, continual updating of escalator safety codes facilitated increased levels of consumer safety as well as a reduction in court cases.
Despite their considerable scope, two Congressional Acts, the Rehabilitation Act of 1973 and the Americans with Disabilities Act of 1990 (ADA), did not directly affect escalators or their public installations. Since Section 504 of the Rehabilitation Act included public transportation systems, for a few years, the United States Department of Transportation considered designs to retrofit existing escalators for wheelchair access. Nonetheless, Foster-Miller Associates’ 1980 plan, Escalator Modification for the Handicapped was ultimately ignored in favor of increased elevator installations in subway systems. Likewise, the ADA provided more accessibility options, but expressly excluded escalators as “accessible means of egress,” advocating neither their removal nor retention in public structures.”ADA Requirements, November 23, 1998,” U.S. Department of Justice, Civil Rights Division, 1998: 3.
In the United States and Canada, new escalators must abide by ASME A17.1 standards, and old/historic escalators must conform to the safety guidelines of ASME A17.3. In Europe, the escalator safety code is EN115.
To enhance passenger safety, newer models of escalators are equipped with one or more of the following safety implementations, as per ASME A17.1 code:
While some escalator accidents are caused by a mechanical failure, most can be avoided by following some simple safety precautions. The Elevator Escalator Safety Foundation is a major advocate for safe riding in the United States and Canada, and sponsors National Elevator Escalator Safety Week each year. Among their publishedElevator Escalator Safety Foundation, "How to Ride Safely on Elevators, Escalators, and Moving Walks," 2007. suggestions for safe riding are the following points:
Nathan Ames, a patent solicitor from Saugus, Massachusetts, is credited with patenting the first "escalator" in 1859, despite the fact that no working model of his design was ever built. His invention, the "revolving stairs," is largely speculative and the patent specifications indicate that he had no preference for materials or potential use (he noted that steps could be upholstered or made of wood, and suggested that the units might benefit the infirm within a household use), though the mechanization was suggested to run either by manual or hydraulic power.Ames, N. “Revolving Stairs," U. S. Patent 25076. Aug. 9 1859. Available: http://uspto.gov
In 1889, Leamon Souder successfully patented the "stairway," an escalator-type device that featured a "series of steps and links jointed to each other." No model was ever built.Souder, Leamon. "Stairway," U. S. Patent 406314. July 2 1889. Available: http://uspto.gov This was the first of at least four escalator-style patents issued to Souder, including two for spiral designs (U. S. Patent Nos. 723,325 and 792,623).
In 1892, Jesse W. Reno, son of American Civil War notable Jesse L. Reno, and an 1883 engineering graduate of Lehigh University, patented the "Endless Conveyor or Elevator."Reno, Jesse W. “Endless Conveyer or Elevator," U. S. Patent 47091815. March 1892. Available: http://uspto.gov A few months after Reno\'s patent was approved, George A. Wheeler patented his ideas for a more recognizable moving staircase, though it was never built.Wheeler, G. A., “Elevator,” U. S. Patent 479864, 2 Aug. 1892. Available: http://uspto.gov. Wheeler’s patents were bought by Charles Seeberger; some features of Wheeler’s designs were incorporated in Seeberger’s prototype built by the Otis Elevator Company in 1899.
Reno produced the first working escalator (he actually called it the "inclined elevator") and installed it alongside the Old Iron Pier at Coney Island, New York in 1896.On record and in practice, this is accepted as the world\'s first operable escalator installation. Dates for the Harrods Piat escalator installation are inconsistent. This particular device was little more than an inclined belt with cast-iron slats or cleats on the surface for traction, and traveled along a 25° incline. A few months later, the same prototype was used for a month-long trial period on the Manhattan side of the Brooklyn Bridge. Reno eventually joined forces with Otis Elevator Company, and retired once his patents were purchased outright. Some Reno-type escalators were still being used in the Boston subway until construction for the Big Dig precipitated their removal. The Smithsonian Institution considered re-assembling one of these historic units from 1914 in their collection of Americana, but "logistics and reassembly costs won out over nostalgia,” and the project was discarded.Topel, Michael. “Ancient Escalator Was a Link to History,” The Patriot-Ledger, 3 Apr. 1995. See also King, John. “A Matter of Perception: Escalators, Moving Walks, and the Motion of Society,” in Up Down Across: Elevators, Escalators and Moving Sidewalks. (Alisa Goetz, ed.) London: Merrell, 2003: 79 – 89.
Around May 1895, Charles Seeberger began drawings on a form of escalator similar to those patented by Wheeler in 1892. This device actually consisted of flat, moving stairs, not unlike the escalators of today, except for one important detail: the step surface was smooth, with no comb effect to safely guide the rider\'s feet off at the ends. Instead, the passenger had to step off sideways. To facilitate this, at the top or bottom of the escalator the steps continued moving horizontally beyond the end of the handrail (like a mini-moving sidewalk) until they disappeared under a triangular "divider" which guided the passenger to either side. Seeberger teamed with Otis Elevator Company in 1899, and together they produced the first commercial escalator which won the first prize at the Paris 1900 Exposition Universelle in France. Also on display at the Exposition were Reno\'s inclined elevator, a similar model by James M. Dodge and the Link Belt Machinery Co., and two different devices by French manufacturers Hallé and Piat.
Piat installed its "stepless" escalator in Harrods Knightsbridge store in 1895, though this date is in dispute. Noted by Bill Lancaster in The Department Store: a Social History, "customers unnerved by the experience were revived by shopmen dispensing free smelling salts and cognac."Lancaster, Bill. The Department Store: a Social History. London: Leicester University Press, 1995: 50. Hocquardt received European patent rights for the Fahrtreppe in 1906. After the Exposition, Hallé continued to sell its escalator device in Europe, but was eventually eclipsed in sales by other major manufacturers.
In the first half of the twentieth century, several manufacturers developed their own escalator products, though they had to market their devices under different names, due to Otis’ hold on the trademark rights to the word “escalator.” Brooklyn-based Peelle Company called their models the Motorstair, and Westinghouse called their model an Electric Stairway. The Toledo-based Haughton Elevator company (now part of Schindler Group) referred to their product as simply Moving Stairs. Kone, Orenstein & Koppel, and Schindler introduced their first escalator models several decades after the Otis Elevator Co., but grew to dominance in the field over time.
Reno worked on his own for several years, gaining success in his own right with installations from Toronto to Cape Town, South Africa. For a time, Otis Elevator sold two types of escalator, referring to the Seeberger model as "step-type" and the Reno model as "cleat-type." The company later combined the best aspects of both inventions (guiding slats and flat steps) and in 1921 produced an escalator similar to the type used today: they called it the "L-type" escalator. It was succeeded by the "M-type," the "O-type," and current models by Otis such as the "NCE-type" escalator.
Reno, in addition to his notoriety for the first “practical” escalator in public use, also bears the unique distinction of designing the very first escalators installed in any underground subway system – a single spiral escalator in the London Underground in 1906, forgotten for several decades.[1] London\'s Transport Museum Photographic Collection, "1906 Escalator Operated on Opening Day of Great Northern Picadilly and Brompton Railway, 15 December 1906," Also the first fully-operational spiral escalator, Reno’s design was nonetheless only one in a series of several similar proposed contraptions. Souder patented two spiral designs (see above), Wheeler drafted spiral stairway plans in 1905, Seeberger devised at least two different spiral units between 1906 and 1911 (including an unrealized arrangement for the London Underground), and Gilbert Luna obtained West German, Japanese, and United States patents for his version of a spiral escalator by 1973. When interviewed for the Los Angeles Times that year, Luna was in the process of soliciting “major firms” for acquisition of his patents and company, but statistics are unclear on the outcome of his endeavors in that regard.Hillinger, Charles. “Spiral Escalator May Be his Wheel of Fortune,” Los Angeles Times, 11 Nov., 1973: 3.
The Mitsubishi Electric Corporation was most successful in its development of “spiral” (more “curve” than true spiral) escalators, and has sold them exclusively since the mid-1980s. The world\'s first "practical" spiral escalator – a Mitsubishi model - was installed in Osaka, Japan, in 1985.Elevators & Escalators - MITSUBISHI ELECTRIC
In use, a major planning advantage presented by spiral escalators is that they take up much less horizontal floor space than traditional units, which frequently house large machine rooms underneath the truss.
Several authors and historians have contributed their own differing interpretations of the source of the word “escalator,” and some degree of misinformation has heretofore proliferated on the internet. For reference, contradictory citations by seven separate individuals, including the Otis Elevator Company itself, are provided below. See: Barrow, Dennis. “Seeberg.doc,” Internal document, Otis Elevator Co., Farmington, CT: United Technologies; “escalator, noun.” OED Online. June 2004. Oxford University Press, available: http://dictionary.oed.com/cgi/entry/50077810; “Otis Firsts: Escalators in the Gaslight Era,” Otis Elevator Co., available: (http://www.otis.com/otis150/section/1,2344,ARC3125_CLI1_RES1_SEC2,00.html); “Subject: History of the Escalator” (unnumbered sales circular letter). Internal document, Otis Elevator Co., Farmington, CT: United Technologies, 16 October 1962; “The Word ‘Escalator,’” Human Interest, Online. The Museum for the Preservation of Elevating History, available: http://www.theelevatormuseum.org/h/h-1.htm; Worthington, Jr., William. “Early Risers,” American Heritage of Invention & Technology, Vol. 4, No. 3 (Winter 1989): 42; and Wosk, Julie. “Perspectives on the Escalator in Photography and Art,” in Up Down Across: Elevators, Escalators and Moving Sidewalks. (Alisa Goetz, ed.) London: Merrell, 2003.
Charles D. Seeberger trademarked the word "escalator" in 1900, to coincide with his device’s debut at the Exposition Universelle. According to his own account, in 1895, his legal counsel advised him to name his new invention, and he then set out to devise a title for it on his own. As evidenced in Seeberger\'s own handwritten documents, archived at the Otis Elevator Company headquarters in Farmington, Connecticut, the inventor consulted "a Latin lexicon" and "adopted as the root of the new word, \'Scala\'; as a prefix, \'E\' and as a suffix, \'Tor.\'De Fazio, Diane H. Like Blood to the Veins: Escalators, their History, and the Making of the Modern World (Master\'s Thesis, Columbia University Graduate School of Architecture, Planning, and Preservation), 2007: 58 – 61. His own rough translation of the word thus created was "means of traversing from," and he intended for the word to be pronounced, "es-CAL-a-tor."De Fazio, 60. Seeberger noted that the public had come to call his invention the "es-ca-LA-tor" by 1906.
"Escalator" was not a combination of other French or Greek words, and is not a derivative of "elevator," which means “one who raises up, a deliverer” in Latin.Lewis, Charlton T. and Charles Short. A Latin Dictionary: Founded on Andrews’ Edition of Freund’s Latin Dictionary. Oxford: Clarendon Press, 1984. Similarly, the root word “scala” does not mean "a flight of steps," but is defined by Lewis and Short’s A Latin Dictionary as the singular form of the plural noun “scalae,” which denotes any of the following: “a flight of steps or stairs, a staircase; a ladder, [or] a scaling-ladder.”Ibid.
The alleged intended capitalization of “escalator” is likewise a topic of debate. Seeberger’s trademark application lists the word not only with the “E” but also with all of the letters capitalized (in two different instances), and he specifies that, “any other form and character of type may be employed . . . without altering in any essential manner the character of [the] trade-mark.” Seeberger, Charles D. “Trade-mark for Passenger-Elevators.” U. S. Trade-mark No. 34724. 2 May 1900. Available: http://uspto.gov That his initial specifications are ostensibly inconsistent, and since Otis Elevator Co. advertisements so frequently capitalized all of the letters in the word, suppositions about the “capital ‘e’” are difficult to formulate.
The verb “escalate” originated in 1922, and has two uses, the primary: “to climb or reach by means of an escalator” or “to travel on an escalator,” and the secondary: “to increase or develop by successive stages; spec. to develop from ‘conventional’ warfare into nuclear warfare.” “escalate, verb.” The Oxford English Dictionary. 2nd ed. 1989. OED Online. Oxford University Press Feb. 2007. (http://dictionary.oed.com/cgi/entry/50077808). The latter definition was first printed in the Manchester Guardian in 1959, but grew to prominent use during the late 1960s and early 1970s.“escalate, verb.²” The Oxford English Dictionary. 2nd ed. 1989. OED Online. Oxford University Press. Feb. 2007. (http://dictionary.oed.com/cgi/entry/50077808).
In 1950, the landmark case Haughton Elevator Co. v. Seeberger precipitated the end of Otis’ reign over exclusive use of the word “escalator,” and simultaneously created a cautionary study for companies and individuals interested in trademark retention.Folsom, Ralph H. and Larry L. Teply. “Trademarked Generic Words,” The Yale Law Journal, Vol. 89, No. 7 (Jun. 1980): 1323 – 1359. Confirming the contention of the Examiner of Trademark Interferences, Assistant Commissioner of Patents Murphy’s decision rejected the Otis Elevator Company’s appeal to keep their trademark intact, and noted that “the term ‘escalator’ is recognized by the general public as the name for a moving stairway and not the source thereof,” observing that the Otis Elevator Co. had “used the term as a generic descriptive term . . . in a number of patents which [had] been issued to them and . . . in their advertising matter.”Haughton Elevator Co. v. Seeberger85 U. S. P. Q. (BNA) 80–81 (Dec. Comm. Pat. 1950). All trademark protections were removed from the word “escalator,” the term was officially genericized, and it fell into the public domain.
As noted above, a few escalator types were installed in major department stores (including Harrods) before the Expo. Escalators proved instrumental in the layout and design of shopping venues in the twentieth century.
By 1898, the first of Reno’s "inclined elevators" were incorporated into the Bloomingdale Bros. store at Third Avenue and 59th Street. This was the first retail application of the devices in the US, and no small coincidence, considering that Reno\'s primary financier was Lyman Bloomingdale, co-owner of the department store with brother Joseph Bloomingdale.Gusrae, G. B. "Moving Sidewalks," Architectural Record, June 1956: 220.
The first “standard” escalator installed on the London Underground was a Seeberger model at Earls Court. Noted above, London\'s Underground installed a rare spiral escalator designed by Reno, William Henry Aston and Scott Kietzman for the Holloway Road Underground station in 1906; it was run for a short time but was taken out of service the same day it debuted.London\'s Transport Museum Photographic Collection, same as reference #12 above. The older lines of the London Underground had many escalators with wooden steps (ca. 1930s) until they were rapidly replaced following the King\'s Cross fire, noted above.
A number of historic escalators still operate across the globe. A few notable examples are:
The longest individual escalators in the world are found in the “metro” or “subway” systems in several cities in Central and Eastern Europe.[citation needed] The longest of all these are in the Park Pobedy station of the famously deep Moscow Metro: opened in 2003, they are 126 metres (410 ft), or 740 steps, long, and take nearly three minutes to transitPark Pobedy. Deep-level stations in St. Petersburg and Kiev have escalators up to approximately 100 metres (330 ft) long. The longest escalator in Prague is at the Náměstí Míru station at 87 metres (290 ft).
The longest escalator on the London Underground system, and indeed in Western Europe, is at Angel station with a length of 60 metres (200 ft)Angel tube station, and a vertical rise of 27.5 metres (90 ft). The longest escalator on the Stockholm Metro is at Västra skogen with a length of 66 metres (220 ft)Västra skogen.
The largest "single truss escalator" is in the Bentall Centre in Kingston upon Thames in Greater London, UK. It connects the ground floor with the second floor with only top and bottom supports.[citation needed]
The longest single-span uninterrupted escalator in the Western Hemisphere is at the Wheaton station of the Washington Metro system. It is 230 feet (70 m) long, and takes almost 2 minutes and 45 seconds to ascend or descend without walking.Washington Metropolitan Area Transit Authority. "Metro Facts," Washington, D. C.: s.n., 2006. available: http://www.wmata.com/about/metrofacts.pdf Metro Facts
The longest escalator in the United States west of the Mississippi is reportedly in the Vermont metro station in Los Angeles.
The longest freestanding (supported only at the ends) escalator in the world is inside CNN Center’s atrium in Atlanta, Georgia. It rises 8 stories and is 205 feet (62 m) long. Originally built as the entrance to the amusement park The World of Sid and Marty Krofft, the escalator is now used for CNN studio tours. www.cnn.com
Okadaya Mores escalator, Kawasaki, Japan.
Westfield Garden State Plaza, Paramus, New Jersey.
According to Guinness, the shortest escalator in the world is in the Okadaya Mores shopping mall in Kawasaki, Japan. Its vertical rise is only 32.8 inches (83 cm).
The shortest escalator in the United States is in the Westfield Garden State Plaza in Paramus, New Jersey. This is likely the shortest escalator pair in the world.
An assortment of escalators in the Yokohama Minato Mirai 21.
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