An escalator is a moving staircase which carries people between floors of a building or structure. It consists of a motor-driven chain of individually linked steps on a track which cycle on a pair of tracks which keep the step tread horizontal.
Escalators are often used around the world in places where lifts would be impractical, or they can be used in conjunction with them. Principal areas of usage include department stores, shopping malls, airports, transit systems (railway/railroad stations), convention centers, hotels, arenas, stadiums and public buildings.
Escalators have the capacity to move large numbers of people. They have no waiting interval, except during mass foot traffic. They can be used to guide people toward main exits or special exhibits and may be weatherproofed for outdoor use. A non-functional escalator can function as a normal staircase, whereas many other methods of transport become useless when they break down or lose power.
While similarly designed, escalators are distinct from travelators, also known as moving walkways. The latter transports people horizontally, along the same floor, not between floors like an escalator.
History
Inventors and manufacturers
Nathan Ames, a patent attorney from Saugus, Massachusetts, is credited with patenting the first "escalator" in 1859, even though 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). The suggested motive power was either manual or hydraulic. "The object of the invention is to enable persons to ascend and descend from one story of a building to another" according to his 1859 patent, while also indicating that they can be "used in the ordinary way, when desired." It is implied that the normal way is identical to that of a stationary staircase.
In 1889, Leamon Souder successfully patented the "stairway", an analogous device that featured a "series of steps and links jointed to each other". No model was ever built. This was the first of at least four escalator-style patents issued to Souder, including two for spiral designs.
On March 15, 1892, Jesse W. Reno patented the "Endless Conveyor or Elevator." 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's patents were bought by Charles Seeberger; some features of Wheeler's designs were incorporated in Seeberger's prototype that was built by the Otis Elevator Company in 1899. Reno produced the first working escalator (called the "inclined elevator") and installed it alongside the Old Iron Pier at Coney Island, New York City, in 1896.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 degree 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 and retired once he had sold his patents. Some wooden Reno-type escalators were still being used at Downtown Crossing (MBTA station) 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, April 3, 1995. See also
Around May 1895, Seeberger began drawings on a form of escalator similar to those patented by Wheeler in 1892. This device 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 miniature moving sidewalk) until they disappeared under a triangular "divider" which guided the passenger to either side. Seeberger teamed with Otis in 1899, and together they produced the first commercial escalator. It won first prize at the 1900 Paris Exposition Universelle. 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 the French manufacturers Hallé and Piat.
Piat installed its "stepless" escalator in Harrods Knightsbridge store, which was unveiled on November 16, 1898, though the company relinquished its patent rights to the department store. 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." The Harrods unit was a continuous leather belt made of "224 pieces... strongly linked together traveling in an upward direction", and was the first "moving staircase" in England."The First Moving Staircase in England," The Drapers' Record, November 19, 1898: 465.
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 holding the trademark rights to the word "escalator." New York-based Peelle Company called their models the Motorstair, while Westinghouse called their model the Electric Stairway. The Toledo-based Haughton Elevator company referred to their product as simply Moving Stairs. The Otis trademark is no longer in effect.
Kone and Schindler introduced their first escalator models several decades after the Otis Elevator Co., but grew to dominate the field over time. Today, Mitsubishi and ThyssenKrupp are Otis's primary rivals. Kone expanded internationally by acquisition in the 1970s, buying out Swedish elevator manufacturer Asea-Graham, and purchasing other minor French, German and Austrian elevator makers before assuming control of Westinghouse's European elevator business. As the last of the "big four" manufacturers to emerge onto the global market, Kone first acquired the Montgomery Elevator company, then took control of Germany's Orenstein & Koppel Rolltreppen.
In the twenty-first century Schindler became the largest maker of escalators and second largest maker of elevators in the world, though their first escalator installation did not occur until 1936. In 1979, the company entered the United States market by purchasing the Haughton Elevator company. A decade later, Schindler assumed control of the North American escalator/elevator operations of Westinghouse, forming Schindler's American division.
Extant historic escalator models
Notable examples of historic escalators still in operation include:
St Anna Pedestrian Tunnel underneath the Scheldt river in Antwerp, Belgium, opened 1933. Maastunnel's bicycle/pedestrian tunnel, adjacent to its car tunnel in Rotterdam, The Netherlands, opened 1942. Tyne Cyclist and Pedestrian Tunnel, Tyne and Wear, England, constructed 1951.These escalators, manufactured by Waygood Otis, were "believed to be the longest link single lift escalators in the world", at the time of installation. Presumably the first escalators in Britain designed specifically for cyclists, they were also the longest in the United Kingdom. At most, they may be the longest extant wooden escalators in the world, though they are no longer in working order. Macy's Herald Square department store upwards escalators, New York, U.S., opened 1920s.Otis L-type units with wood treads and replacement metal treads, only in escalators heading upwards from the first to the seventh stories.
Etymology
Authors and historians have offered multiple interpretations of the source of the word "escalator", and some degree of misinformation then proliferated. 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, ; "Subject: History of the Escalator" (unnumbered sales circular letter). Internal document, Otis Elevator Co., Farmington, CT: United Technologies, October 16, 1962; "The Word 'Escalator'" , Human Interest, Online. The Museum for the Preservation of Elevating History 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.
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. As evidenced in Seeberger's handwritten documents, 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 (). By 1906, Seeberger noted that the public had instead come to pronounce it ().De Fazio, 60.
"Escalator" was not a combination of other French or Greek words, and was never a derivative of "elevator" in the original sense, which means "one who raises up, a deliverer" in Latin. Similarly, the root word "" does not mean "a flight of steps", but is the singular form of the plural noun "", which can denote any of: "a flight of steps or stairs, a staircase; a ladder, [or] a scaling-ladder."
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. May 29, 1900. Available: http://uspto.gov Otis Elevator Co. advertisements so frequently capitalized all of the letters in the word.