Escalator: Difference between revisions

 

The handrail provides a handhold for passengers while they are riding the escalator. The handrail is pulled along its own track by a chain that is connected to the main drive gear by a series of pulleys, keeping it at the same speed as the steps. Four distinct sections make up the rail: at its center is a "slider", also known as a "glider ply", which is a layer of a cotton or synthetic textile that allows the rail to move smoothly along its track. The "[[tension member]]" lies on the slider and consists of either steel cable or flat steel tape, providing the handrail with tensile strength and flexibility. The inner components, on top of the tension member, are made of chemically treated rubber designed to prevent the layers from separating. Finally, the outer layer{{mdash}}the part that passengers see—is the cover, typically a blend of synthetic polymers and rubber. Covers are designed to resist degradation from environmental conditions, mechanical wear and tear and vandalism. In a factory, handrails are constructed by feeding rubber through an extrusion machine to produce layers of the required size and type in order to match specific orders. The component layers of fabric, rubber and steel are shaped by workers before being fed into the presses which fuse them together. In the mid-twentieth century, some handrail designs consisted of a rubber bellows, with rings of smooth metal cladding called "bracelets" between each coil. This gave the handrail a rigid yet flexible feel. Additionally, each bellows section was no more than around a metre long, so if part of the handrail was damaged, only the bad segment needed to be replaced. These forms of handrail have largely been replaced with fabric-and-rubber railings. Being made of either metal, [[sandwich panel]], or glass, the balustrade panel supports the handrails of the escalator. It also provides additional protection for the handrail and passengers. Some escalators have direction arrows on the ends of the balustrade. Escalators' on/off buttons are frequently located at the ends of the balustrade. Moving walkways often use balustrades in the same way. The bottom of the balustrade is called a skirt panel. It is notorious in this art for being a frequent site of injuries and failures, due to the possible entrapment of materials (including body parts) in the machinery. Multiple solutions have been suggested for this issue, including coating with a low-friction material, employing bristles, and others.<ref name=":0" />

 

The track system is built into the truss to guide the step chain, which continuously pulls the steps from the bottom platform and back to the top in an endless loop. One track guides the front wheels of the steps (called the step-wheel track) and another guides the back wheels of the steps (called the trailer-wheel track). The relative positions of these tracks cause the steps to form a staircase as they move out from under the comb plate. Along the straight section of the truss the tracks are at their maximum distance apart. This configuration forces the back of one step to be at a 90-degree angle relative to the step behind it. This right angle forces the steps into a shape resembling a staircase. At the top and bottom of the escalator, the two tracks converge so that the front and back wheels of the steps are almost in a straight line. This causes the stairs to lay in a flat sheetlike arrangement, one after another, so they can easily travel around the bend in the curved section of track. The tracks carry the steps down along the underside of the truss until they reach the bottom landing, where they pass through another curved section of track before exiting the bottom landing. At this point, the tracks separate and the steps once again assume a staircase configuration. This cycle is repeated continually as the steps are pulled from bottom to top and back to the bottom again.

The Mitsubishi Electric Corporation was most successful in its development of spiral or helical escalators, and it alone has sold them since the mid-1980s. The world's first practical spiral escalator—a Mitsubishi model—was installed in [[Osaka]], Japan, in 1985.<ref>{{cite web|url=http://www.mitsubishielectric.com/elevator/innovations/spiral_escalators.html |title=Elevators & Escalators |publisher=mitsubishielectric.com |access-date=September 18, 2012}}</ref> Helixator, an experimental helical escalator design that currently exists as a prototype scale model, could further reduce floor space demands. Its design has several innovations that allow a continuous helix; driven by a linear motor instead of a chain system, it spreads force evenly along the escalator path, avoiding excessive force on the top chain links and hence avoiding the geometry, length, and height limits of standard escalators.<ref>{{cite web|url=https://la-grazia.com/e-learning/en-115-standard-for-escalators-and-moving-walks/|title='Spiral' Escalator and Moving Walk could give crowds a lift|last=Harris|first=Stephen|date=23 December 2010|access-date=2012-03-15 }}</ref> [[Emporium Centre San Francisco]], San Francisco, California, United States, is the first spiral escalator in the Western Hemisphere.<ref>Sachner, Paul M. "Two on the Town: Heritage on the Garden, in Boston, and San Francisco Centre, in San Francisco", ''Architectural Record'', vol. 177, no. 6, May 1989: 122–127.</ref>

 

 

== Safety ==

 

The [[King's Cross fire]] of 1987 illustrated the demanding nature of escalator upkeep and the devices' propensity to collect "fluff" and other small debris when not properly maintained.<ref>{{Cite journal|last=Moodie|first=K.|date=1992-01-01|title=The King's Cross fire: damage assessment and overview of the technical investigation|journal=Fire Safety Journal|series=Special Issue: The King's Cross Underground Fire|volume=18|issue=1|pages=13–33|doi=10.1016/0379-7112(92)90045-E|bibcode=1992FirSJ..18...13M }}</ref> The [[King's Cross fire#The Fennell Report|official inquiry]] determined that the fire started slowly, smoldering virtually undetected for a time, and then exploded into the ticket hall above in a previously unrecognised phenomenon now known as the "[[trench effect]]". In the escalators' undercarriage, approximately {{convert|8800|kg}} of accumulated [[detritus]] acted as a [[Capillary action|wick]] to a neglected buildup of interior lubricants; wood veneers, paper and plastic advertisements, solvent-based paint, plywood in the ticket hall, and [[melamine]] combustion added to the impact of the calamity.<ref>”Building Design Editorial: the King’s Cross Inquiry", ''Building Design'', November 19, 1988: 9</ref> Following the report, older wooden escalators were removed from service in the [[London Underground]]. Additionally, sections of the London Underground that were actually below ground were made [[Smoking ban|non-smoking]]; ultimately, the whole system became a smoke-free zone.

 

Some of longest and fastest escalators in Europe are found in [[Prague]], and are set to be replaced with slower versions in order to meet modern safety standards.<ref>{{Cite web|date=2023-10-25|title= Fast-moving Escalators in Metro Station Namesti Miru |website=Prague Now |url=https://prague-now.com/history/fast-moving-escalators-in-metro-station-namesti-miru/ |url-status=live |archive-url= https://web.archive.org/web/20231203171835/https://prague-now.com/history/fast-moving-escalators-in-metro-station-namesti-miru/ |archive-date= Dec 3, 2023 }}</ref>

[[File:Escalator in Umeda.jpg|thumb|upright|Riders stand to the right on this escalator in [[Umeda]], [[Osaka]], Japan]]

 

 

In certain high-traffic systems, including the [[East Japan Railway Company]] and the [[Prague metro]], escalator users are encouraged to stand on whichever side they choose, with the aim of preventing wear and tear and asymmetrical burdening.<ref>{{cite news|last1=Baier|first1=Viktor|title=Pohyblivé schody neboli eskalátory|url=http://www.dpp.cz/download-file/1158/01-leden-2008.pdf|access-date=10 November 2014|work=DP Kontakt|issue=1/2008|publisher=Prague public transport company|archive-date=10 November 2014|archive-url=https://web.archive.org/web/20141110201856/http://www.dpp.cz/download-file/1158/01-leden-2008.pdf|url-status=dead}}</ref> All Tokyo metro stations also have posters next to the escalators that ask users not to walk but instead to stand on either side.

{{commonscat|Escalators}}

 

 

{{Public transport}}