 Kraków manhole cover (note integral hinge)
 Manhole cover in Rome with SPQR inscription
 German standard manhole cover with infills of concrete in Berlin A manhole cover is a removable plate forming the lid over the opening of a manhole, to prevent someone from falling in and to keep unauthorized persons out. Image File history File linksMetadata Download high resolution version (3456x2304, 3874 KB) Close-up of pick holes in a manhole cover in Palo Alto, California. ...
Image File history File linksMetadata Download high resolution version (3456x2304, 3874 KB) Close-up of pick holes in a manhole cover in Palo Alto, California. ...
Downtown Palo Alto Palo Alto is a city in Santa Clara County, in the San Francisco Bay Area of California, USA. Palo Alto is located at the northern end of the Silicon Valley, and is home to Stanford University (which is technically located in an adjacent area — Stanford, California), and...
Image File history File linksMetadata Download high resolution version (3008x2000, 3359 KB) A manhole of Krakóws sewer system File links The following pages link to this file: Manhole cover Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize...
Image File history File linksMetadata Download high resolution version (3008x2000, 3359 KB) A manhole of Krakóws sewer system File links The following pages link to this file: Manhole cover Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize...
For other uses, see Krakow (disambiguation). ...
Image File history File linksMetadata Download high-resolution version (1404x1106, 344 KB) A painted manhole cover in Matsumoto, Japan. ...
Image File history File linksMetadata Download high-resolution version (1404x1106, 344 KB) A painted manhole cover in Matsumoto, Japan. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
Download high resolution version (2592x1944, 1490 KB) Wikipedia does not have an article with this exact name. ...
Download high resolution version (2592x1944, 1490 KB) Wikipedia does not have an article with this exact name. ...
County District Municipality NO-1601 Administrative centre Trondheim Mayor (2003-) Rita Ottervik (AP) Official language form Neutral Area - Total - Land - Percentage Ranked 258 342 km² 322 km² 0. ...
Download high resolution version (2048x1360, 1211 KB)Roman manhole cover with SPQR inscription File links The following pages link to this file: SPQR Categories: GFDL images | NowCommons ...
Download high resolution version (2048x1360, 1211 KB)Roman manhole cover with SPQR inscription File links The following pages link to this file: SPQR Categories: GFDL images | NowCommons ...
For the series of murder mystery novels, see SPQR series. ...
Image File history File links Download high resolution version (1728x2304, 1181 KB) Beschreibung / Description Berlin – Schachtdeckel; Guss- und Armaturwerk Kaiserslautern / manhole cover; Guss- und Armaturwerk Kaiserslautern Quelle / Source selbst fotografiert / taken by myself Datum der Aufnahme 2005-02-08 Fotograf / Photographer Georg Slickers Bearbeitung / edits gedreht / rotated Kommentar / comment Lizenz...
Image File history File links Download high resolution version (1728x2304, 1181 KB) Beschreibung / Description Berlin – Schachtdeckel; Guss- und Armaturwerk Kaiserslautern / manhole cover; Guss- und Armaturwerk Kaiserslautern Quelle / Source selbst fotografiert / taken by myself Datum der Aufnahme 2005-02-08 Fotograf / Photographer Georg Slickers Bearbeitung / edits gedreht / rotated Kommentar / comment Lizenz...
This article is about the capital of Germany. ...
Image File history File linksMetadata Size of this preview: 634 × 599 pixelsFull resolution (1271 × 1201 pixel, file size: 240 KB, MIME type: image/jpeg) Heavy cast iron manhole cover of the city water main in Vilnius. ...
Image File history File linksMetadata Size of this preview: 634 × 599 pixelsFull resolution (1271 × 1201 pixel, file size: 240 KB, MIME type: image/jpeg) Heavy cast iron manhole cover of the city water main in Vilnius. ...
State motto: Lithuanian: Visų šalių proletarai, vienykitės! Translation: Workers of the world, unite! Capital Vilnius Official language None. ...
A municipal water system is a large system of reservoirs and large-scale piping which supplies fresh water, suitable for human consumption, to houses and other residences. ...
Not to be confused with Vilnius city municipality. ...
For other uses, see Manhole (disambiguation). ...
Companies like Ainsleigh Stainless , Fabweld , Peter Savage & Channel Covers manufacture many types of manhole covers in the UK .
Manhole covers usually weigh more than 100 pounds (roughly 50 kg), partly because the weight keeps them in place when traffic passes over them, and partly because they are often made out of cast iron, sometimes with infills of concrete. This makes them inexpensive and strong but heavy. A manhole cover sits on metal base, with a smaller inset rim which fits the cover. The base and cover are sometimes called "castings," because they are made by a casting process [1]. Look up pound in Wiktionary, the free dictionary. ...
KG, kg or Kg can refer to several things: Kilogram, the SI base unit of mass. ...
Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon (alloys with less carbon are carbon steel by definition). ...
This article is about the construction material. ...
They usually feature "pick holes", in which a hook handle is inserted to lift them. Pick holes can be concealed for a more watertight lid, or can allow light to shine through. A manhole pick or hook is typically used to lift them, though other tools can be used as well.
Manhole covers are generally made using sand casting techniques[2]. India has become the world leader in manufacturing manhole covers, driving many manufacturers in other countries out of business.[3] Its extremely low labor costs have overcome even the cost of shipping such heavy objects. A few of the leading manufacturers of manhole castings and covers are Crescent Foundry, Neenah Foundry Company and Welcast. Casting is the process of production of objects by pouring molten material into a cavity called a mould which is the negative of the object, and allowing it to cool and solidify. ...
Although the covers are too large to be collectible, their ubiquity and the many patterns and descriptions printed on them has led some people to collect pictures of covers from around the world. A collectible (or collectable) is typically a manufactured item designed for people to collect. ...
Despite their weight and cumbersome nature, manhole covers are sometimes stolen, usually for resale as scrap, particularly when metal prices rise.[4] Image:Missing Manhole. ...
Why are they generally round?
The question of why manhole covers are typically round, at least in the U.S., was made famous by Microsoft when they began asking it as a job-interview question.[5] Originally meant as a psychological assessment of how one approaches a question with more than one "right" answer, the problem has produced a number of alternate explanations, from the pragmatic ("Manhole covers are round because manholes are round.")[5] to the philosophical. For other uses of terms redirecting here, see US (disambiguation), USA (disambiguation), and United States (disambiguation) Motto In God We Trust(since 1956) (From Many, One; Latin, traditional) Anthem The Star-Spangled Banner Capital Washington, D.C. Largest city New York City National language English (de facto)1 Demonym American...
Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ...
Reasons for the shape include:
- A round manhole cover cannot fall through its circular opening, whereas a square manhole cover may fall in if it were inserted diagonally in the aperture (A Reuleaux triangle or other curve of constant width would also serve this purpose, but round covers are much easier to manufacture.)
- Round tubes are the strongest and most material-efficient shape against the compression of the earth around them, and so it is natural that the cover of a round tube assume a circular shape.
- The bearing surfaces of manhole frames and covers are machined to assure flatness and prevent them from becoming dislodged by traffic. Round castings are much easier to machine using horizontal boring mills.
- Circular covers do not need to be rotated to align them when covering a circular manhole.
- Human beings have a roughly circular cross-section.
- A round manhole cover can be more easily moved by being rolled.
- If an automobile rolls over a dislodged manhole of another shape, the sharp corners could puncture the automobile's tire, whereas a circle doesn't have corners.
- It's easier to dig a circular hole.
- Tradition
- Aesthetics
- Supply. Most manhole covers are made by a few large companies. If you want a different shape, you will have to pay more to have them custom-made or you will have to make them yourself.
Other manhole shapes can be found, usually squares or rectangles. Nashua, New Hampshire may be unique in the U.S. for having triangular manhole covers that point in the direction of the underlying flow. The city is phasing out the triangles, which were made by a local foundry, because they are not large enough to meet modern safety standards, and larger triangles cannot be found. [1] The Reuleaux triangle is a constant width curve based on an equilateral triangle. ...
For closed convex planar bodies whose boundary is a smooth curve, one notes that there are exactly two parallel tangent lines to the boundary curve in any given direction. ...
Nickname: Gate City Location in Hillsborough County, New Hampshire Coordinates: Country United States State New Hampshire County Hillsborough Incorporated 1746 Government - Mayor Bernard A. Streeter Area - City 31. ...
A foundry is a factory which produces castings of metal, both ferrous and non-ferrous. ...
Can a race car lift a manhole cover? Modern racing cars create so much vacuum due to their aerodynamics that they can lift a manhole cover off the ground. During races on city streets, the manhole covers must therefore be welded down to prevent injury. In 1990, during the Group C World Sportscar Championship race in Montreal, racer Jésus Pareja's car struck a manhole cover that was lifted by the ground effect of the car he was following, causing his car to catch fire.[6] Auto racing (also known as automobile racing or autosport) is a sport involving racing automobiles. ...
Look up Vacuum in Wiktionary, the free dictionary. ...
The 1990 World Sportscar Championship season was the 38th FIA World Sports-Prototype Championship season. ...
Group C was a category of auto racing, and was introduced into sports car racing by the FIA (the governing body of World motor racing) during the early 1980s. ...
The World Sportscar Championship was a series run by the FIA from 1953 to 1992. ...
Nickname: Motto: Concordia Salus (well-being through harmony) Coordinates: , Country Province Region Montréal Founded 1642 Established 1832 Government - Mayor Gérald Tremblay Area [1][2][3] - City 365. ...
Ground effect is an aerodynamic effect used in car design, which has been exploited to create downforce, particularly in racing cars. ...
The first nuclear propelled manmade object in space? According to urban legend, a manhole cover was accidentally launched from its shaft during an underground nuclear test in the 1950s, at great enough speed to achieve escape velocity. The myth is based on a real incident during the Operation Plumbbob nuclear tests, where a heavy (900 kg) steel plate cap was blasted off the test shaft at an unknown velocity, and appears as a blur on a single frame of film of the test, and was never recovered. A calculation before the event gave a predicted speed of 6 times Earth escape velocity, but the calculation is unlikely to have been accurate and they did not believe that it would leave the Earth in reality. After the event, Dr. Robert R. Brownlee described the best estimate of the cover's speed from the photographic evidence as "going like a bat!!"[7] [8] For other uses, see Urban legend (disambiguation). ...
The 1950s decade refers to the years of 1950 to 1959 inclusive. ...
For other senses of this term, see escape velocity (disambiguation). ...
The Smoky shot of Operation Plumbbob. ...
For other senses of this term, see escape velocity (disambiguation). ...
This incident was used as part of the technical justification for the Orion project. ' An artists conception of the NASA reference design for the Project Orion spacecraft powered by nuclear propulsion. ...
See also . ...
A public utility is a company that maintains the infrastructure for a public service. ...
Storm drain in use A storm drain, storm sewer, stormwater drain (Australia and New Zealand) or surface water system (UK) is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. ...
For the art of stitching, see Sewing. ...
For the series of murder mystery novels, see SPQR series. ...
References - ^ Manhole Cover: How Products are Made
- ^ Manhole Cover: How Products are Made
- ^ Made in India, Little India
- ^ Severely punish theft of manhole covers, Liu Shinan (China Daily) 2005-12-21
- ^ a b Poundstone, William (2003). How Would You Move Mount Fuji? Microsoft's Cult of the Puzzle – How the World's Smartest Company Selects the Most Creative Thinkers. Little, Brown. ISBN 0-316-91916-0.
- ^ Classic Cars Race Results Database
- ^ Learning to Contain Underground Nuclear Explosions By Dr. Robert R. Brownlee - June 2002
- ^ Operation Plumbob at the Nuclear Weapon Archive
Printed references: - Melnick, Mimi (1994). Manhole Covers, MIT Press, USA. ISBN 0-262-13302-4
- Stuart, Diana (2003). Designs Underfoot: The Art of Manhole Covers in New York City, The Lyons Press, USA. ISBN 1-58574-639-8
- Raymond, Douglas (2007). Transylvanian Street Metal, http://www.blurb.com/bookstore/detail/77885
External links Wikimedia Commons has media related to: This article does not cite any references or sources. ...
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