eccentric

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adjective

Deviating from the customary: bizarre, cranky, curious, erratic, freakish, idiosyncratic, odd, outlandish, peculiar, quaint, queer, quirky, singular, strange, unnatural, unusual, weird. Slang kooky, screwball. British Slang rum, rummy². See usual/unusual.

noun

A person regarded as strange, eccentric, or crazy: crackpot, crazy, lunatic. Informal crank, loon, loony. Slang cuckoo, ding-a-ling, dingbat, kook, nut, screwball, weirdie, weirdo. See wise/foolish.

Definition: bizarre, unusual
Antonyms: boring, common, dull, normal, ordinary, plain, regular, standard, unexciting, usual

n

Definition: person who is bizarre, unusual
Antonyms: normal, standard

Not having the same center or center line.

eccentric head and shaft

Tutor's tip: "Acentric" means off-center, while "eccentric" describes someone who is interesting in a peculiar or abnormal way.

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1. a deviation from the normal or conventional. adj 2. away from the central or reference position.

• Special, Bright, Skillful, or Unusual
• Agitation, Abnormality, and Instability - eccentric: one who behaves abnormally; oddball

Eccentric sheave, with strap and eccentric rod fitted.

In mechanical engineering, an eccentric is a circular disk (eccentric sheave) solidly fixed to a rotating axle with its centre offset from that of the axle (hence the word "eccentric", out of the centre).^[1]

It is most often employed in steam engines and used to convert rotary into linear reciprocating motion in order to drive a sliding valve or a pump ram. In order to do so an eccentric usually has a groove at its circumference around which is closely fitted a circular collar (eccentric strap) attached to which an eccentric rod is suspended in such a way that its other end can impart the required reciprocating motion. A return crank fulfils the same function except that it can only work at the end of an axle or on the outside of a wheel whereas an eccentric can also be fitted to the body of the axle between the wheels. Unlike a cam, which also converts rotary into linear motion at almost any rate of acceleration and deceleration, an eccentric or return crank can only impart simple harmonic motion.

Contents 1 On bicycles 2 Gallery 3 See also 4 References

On bicycles

Eccentric bottom bracket on a Burley tandem bicycle held in place with two set screws

The term is also used to refer to the device often used on tandem bicycles with timing chains, single-speed bicycles with a rear disc brake or an internal-geared hub, or any bicycle with vertical dropouts and no derailleur, to allow slight repositioning, fore and aft, of a bottom bracket in order to properly tension the chain.^[2]

They may be held in place by a built-in wedge, set screws threaded into the bottom bracket shell, or pinch bolts that tighten a split bottom bracket shell.^[3]As a standard sized bottom bracket threads into the eccentric, an oversized bottom bracket shell is required to accommodate the eccentric.

Gallery

• 

  An animation of an eccentric sheave, with strap and eccentric rod fitted

• 

  Example of using eccentrics on a steam locomotive

See also

Wikimedia Commons has media related to: Eccentrics

• Balance shaft
• Cam
• Crank (mechanism)
• Concentric
• Crankshaft
• Linkage (mechanical)

References

1. ^ Norton, Robert L. (2004). Design of machinery (3rd ed.). McGraw-Hill. ISBN 0-07-247046-1. 
2. ^ Brown, Sheldon. "Sheldon Brown's Bicycle Glossary E-F: Eccentric". Sheldon Brown. http://www.sheldonbrown.com/gloss_e-f.html. Retrieved 2007-06-09. 
3. ^ "Cannondale 1FG Easy Chain Tensioning". http://www.cannondale.com/bikes/03/ce/model-3mrss.html. Retrieved 2007-10-19. 

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
adj. - excentrisk
n. - ikke cirkulær, aparte

Nederlands (Dutch)
excentriek(eling), excentrisch

Français (French)
adj. - excentrique, original, bizarre, (Math, Tech) excentrique
n. - excentrique, original, (Tech) excentrique

Deutsch (German)
n. - Exzentriker
adj. - exzentrisch

Ελληνική (Greek)
n. - ιδιότροπος (άνθρωπος), έκκεντρο
adj. - εκκεντρικός, ιδιότροπος, αλλόκοτος, παράξενος, έκκεντρος, παράκεντρος

Italiano (Italian)
eccentrico

Português (Portuguese)
n., -
adj. - excêntrico (m)

Русский (Russian)
чудак, оригинал, эксцентрик, эксцентричный

Español (Spanish)
adj. - excéntrico, excéntrica (tec.), estrafalario, estrambótico, extravagante, (geom) que no tiene el mismo centro, elíptico, que no está en el centro
n. - excéntrico, estrafalario, estrambótico, extravagante

Svenska (Swedish)
n. - excentrisk människa, original, särling, excenter (skiva) (mek.)
adj. - excentrisk, originell, excenter- (mek.)

中文（简体）(Chinese (Simplified))
古怪的, 不同圆心的, 反常的, 古怪的人, 偏心轮, 偏心圆

中文（繁體）(Chinese (Traditional))
adj. - 古怪的, 不同圓心的, 反常的
n. - 古怪的人, 偏心輪, 偏心圓

한국어 (Korean)
adj. - 보통이 아닌, 괴짜의, 중심을 달리하는
n. - 괴짜

日本語 (Japanese)
adj. - 普通でない, 一風変わった, 中心を異にする, 円でない
n. - 奇人

العربيه (Arabic)
‏(الاسم) شخص شاذ أو غريب الأطوار (صفه) شاذ, منحرف عن المركز‏

עברית (Hebrew)
adj. - ‮לא מעגלי, לא משותף-מרכז, מוזר וגחמני בהופעתו או בהתנהגותו‬
n. - ‮מתקן לשינוי תנועה מעגלית לתנועת קדימה-אחורה במנוע‬

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