View source for Machine

{{short description|Powered mechanical device}}
{{About|devices designed to perform tasks}}
{{Redirect|Machinery}}
{{pp-vandalism|small=yes}}
[[File:Woman operator operating milling machine - DPLA - 34dc4b36bfa1d73f44c4d6983b12f77c (cropped).jpg|thumb|upright=1.2|A worker operating a [[milling machine]] in the early 20th century]]
A '''machine''' is a [[thermodynamic system]] that uses [[Power (physics)|power]] to apply [[force]]s and control [[Motion|movement]] to perform an action. The term is commonly applied to artificial devices, such as those employing [[engine]]s or motors, but also to natural biological macromolecules, such as [[molecular machine]]s. Machines can be driven by [[Animal power|animals]] and [[Human power|people]], by natural forces such as [[Wind power|wind]] and [[Water power|water]], and by [[Chemical energy|chemical]], [[Thermal energy|thermal]], or [[electricity|electrical]] power, and include a system of [[mechanism (engineering)|mechanisms]] that shape the [[actuator]] input to achieve a specific application of output forces and movement. They can also include [[computers]] and sensors that monitor performance and plan movement, often called mechanical systems.

Renaissance natural philosophers identified six [[simple machine]]s which were the elementary devices that put a load into motion, and calculated the ratio of output force to input force, known today as [[mechanical advantage]].<ref name="Usher">{{cite book
 |last        = Usher
 |first       = Abbott Payson
 |title       = A History of Mechanical Inventions
 |publisher   = Courier Dover Publications
 |year        = 1988
 |location    = USA
 |pages       = 98
 |url         = https://books.google.com/books?id=xuDDqqa8FlwC&pg=PA196
 |isbn        = 978-0-486-25593-4
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20160818135506/https://books.google.com/books?id=xuDDqqa8FlwC&pg=PA196
|archive-date = 2016-08-18
}}</ref>

Modern machines are complex systems that consist of structural elements, [[Mechanism (engineering)|mechanisms]] and control components and include interfaces for convenient use. Examples include: a wide range of [[vehicle]]s, such as [[train]]s, [[Car|automobiles]], [[boat]]s and [[airplane]]s; [[Home appliance|appliances]] in the home and office, including computers, building [[air handler|air handling]] and [[Plumbing|water handling systems]]; as well as [[Agricultural machinery|farm machinery]], [[machine tool]]s and [[Automation|factory automation]] systems and [[robot]]s.

==Etymology==
The English word ''machine'' comes through [[Middle French]] from [[Latin]] {{lang|la|machina}},<ref name=AHD>''The American Heritage Dictionary'', Second College Edition. Houghton Mifflin Co., 1985.</ref> which in turn derives from the [[ancient Greek|Greek]] ([[Doric Greek|Doric]] {{lang|grc|μαχανά }} {{transliteration|grc|makhana}}, [[Ionic Greek|Ionic]] {{lang|grc|μηχανή }} {{transliteration|grc|mekhane}} 'contrivance, machine, engine',<ref>[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dmhxanh%2F "μηχανή"] {{webarchive|url=https://web.archive.org/web/20110629140054/http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=mhxanh%2F |date=2011-06-29 }}, Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus project</ref> a derivation from {{lang|grc|μῆχος }} {{transliteration|grc|mekhos}} 'means, expedient, remedy'<ref>[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dmh%3Dxos "μῆχος"] {{webarchive|url=https://web.archive.org/web/20110629140106/http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=mh=xos |date=2011-06-29 }}, Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus project</ref>).<ref>Oxford Dictionaries, [https://web.archive.org/web/20180426213204/https://en.oxforddictionaries.com/definition/machine machine]</ref> The word ''mechanical'' (Greek: {{lang|grc|μηχανικός}}) comes from the same Greek roots. A wider meaning of 'fabric, structure' is found in classical Latin, but not in Greek usage. This meaning is found in late medieval French, and is adopted from the French into English in the mid-16th century.

In the 17th century, the word machine could also mean a scheme or plot, a meaning now expressed by the derived [[:wikt:machination|machination]]. The modern meaning develops out of specialized application of the term to [[stagecraft|stage engines]] used in [[Elizabethan theater|theater]] and to military [[siege engine]]s, both in the late 16th and early 17th centuries. The [[OED]] traces the formal, modern meaning to [[John Harris (writer)|John Harris]]' ''[[Lexicon Technicum]]'' (1704), which has:

:''Machine, or Engine, in Mechanicks, is whatsoever hath Force sufficient either to raise or stop the Motion of a Body. Simple Machines are commonly reckoned to be Six in Number, viz. the Ballance, Leaver, Pulley, Wheel, Wedge, and Screw. Compound Machines, or Engines, are innumerable.''
The word ''[[:wikt:engine|engine]]'' used as a (near-) synonym both by Harris and in later language derives ultimately (via [[Old French]]) from Latin {{lang|la|ingenium}} 'ingenuity, an invention'.

==History==
[[File:Flint hand axe.JPG|thumb|upright=0.6|right|A flint [[hand axe]] was found in [[Winchester]].]]
The [[hand axe]], made by chipping flint to form a [[wedge (mechanical device)|wedge]], in the hands of a human transforms force and movement of the tool into a transverse splitting forces and movement of the workpiece. The hand axe is the first example of a [[wedge]], the oldest of the six classic [[simple machine]]s, from which most machines are based. The second oldest simple machine was the [[inclined plane]] (ramp),<ref name="Reuleaux">Karl von Langsdorf (1826) ''Machinenkunde'', quoted in  {{cite book     | last = Reuleaux  | first = Franz   | title = The kinematics of machinery: Outlines of a theory of machines  | publisher = MacMillan  | year = 1876  | pages = [https://archive.org/details/kinematicsmachi01reulgoog/page/n524 604] | url = https://archive.org/details/kinematicsmachi01reulgoog}}</ref> which has been used since [[prehistoric]] times to move heavy objects.<ref name="Conn">Therese McGuire, ''Light on Sacred Stones'', in {{cite book | last = Conn  | first = Marie A.   |author2=Therese Benedict McGuire  | title = Not etched in stone: essays on ritual memory, soul, and society  | publisher = University Press of America  | year = 2007  | pages = 23  | url = https://books.google.com/books?id=kEPkDyvek3sC&pg=PA23 | isbn = 978-0-7618-3702-2}}</ref><ref name="Dutch">{{cite web  | last = Dutch  | first = Steven  | title = Pre-Greek Accomplishments  | work = Legacy of the Ancient World  | publisher = Prof. Steve Dutch's page, Univ. of Wisconsin at Green Bay  | year = 1999  | url = http://www.uwgb.edu/dutchs/westtech/xancient.htm  | access-date = March 13, 2012  | archive-date = August 21, 2016  | archive-url = https://web.archive.org/web/20160821064729/http://www.uwgb.edu/dutchs/westtech/xancient.htm  | url-status = dead  }}</ref>

The other four simple machines were invented in the [[ancient Near East]].<ref>{{cite book |last1=Moorey |first1=Peter Roger Stuart |title=Ancient Mesopotamian Materials and Industries: The Archaeological Evidence |date=1999 |publisher=[[Eisenbrauns]] |isbn=9781575060422}}</ref> The [[wheel]], along with the [[wheel and axle]] mechanism, was invented in [[Mesopotamia]] (modern Iraq) during the 5th millennium BC.<ref>{{cite book|title=A Companion to the Archaeology of the Ancient Near East|author=D.T. Potts|year=2012|page=285}}</ref> The [[lever]] mechanism first appeared around 5,000 years ago in the [[Near East]], where it was used in a simple [[balance scale]],<ref name="Paipetis">{{cite book |last1=Paipetis |first1=S. A. |last2=Ceccarelli |first2=Marco |title=The Genius of Archimedes -- 23 Centuries of Influence on Mathematics, Science and Engineering: Proceedings of an International Conference held at Syracuse, Italy, June 8-10, 2010 |date=2010 |publisher=[[Springer Science & Business Media]] |isbn=9789048190911 |page=416}}</ref> and to move large objects in [[ancient Egyptian technology]].<ref>{{cite book |last1=Clarke |first1=Somers |last2=Engelbach |first2=Reginald |title=Ancient Egyptian Construction and Architecture |date=1990 |publisher=[[Courier Corporation]] |isbn=9780486264851 |pages=86–90}}</ref> The lever was also used in the [[shadoof]] water-lifting device, the first [[Crane (machine)|crane]] machine, which appeared in Mesopotamia {{circa|3000 BC}},<ref name="Paipetis"/> and then in [[ancient Egyptian technology]] {{circa|2000 BC}}.<ref>{{cite book |last1=Faiella |first1=Graham |title=The Technology of Mesopotamia |date=2006 |publisher=[[The Rosen Publishing Group]] |isbn=9781404205604 |page=27 |url=https://books.google.com/books?id=bGMyBTS0-v0C&pg=PA27}}</ref> The earliest evidence of [[pulley]]s date back to Mesopotamia in the early 2nd millennium BC,<ref name="Eisenbrauns">{{cite book |last1=Moorey |first1=Peter Roger Stuart |title=Ancient Mesopotamian Materials and Industries: The Archaeological Evidence |date=1999 |publisher=[[Eisenbrauns]] |isbn=9781575060422 |page=4}}</ref> and [[ancient Egypt]] during the [[Twelfth Dynasty of Egypt|Twelfth Dynasty]] (1991–1802 BC).<ref>{{cite book |last1=Arnold |first1=Dieter |title=Building in Egypt: Pharaonic Stone Masonry |date=1991 |publisher=Oxford University Press |isbn=9780195113747 |page=71}}</ref> The [[Screw (simple machine)|screw]], the last of the simple machines to be invented,<ref name="Woods">{{cite book   | last =  Woods| first = Michael 
|author2=Mary B. Woods| title = Ancient Machines: From Wedges to Waterwheels| publisher = Twenty-First Century Books| year = 2000| location = USA| pages = 58| url = https://books.google.com/books?id=E1tzW_aDnxsC&pg=PA58| isbn = 0-8225-2994-7}}</ref> first appeared in [[Mesopotamia]] during the [[Neo-Assyrian Empire|Neo-Assyrian]] period (911–609) BC.<ref name="Eisenbrauns"/> The [[Egyptian pyramids]] were built using three of the six simple machines, the inclined plane, the wedge, and the lever.<ref>{{cite book|title=Ancient Machines: From Grunts to Graffiti|last=Wood|first=Michael|publisher=Runestone Press|year=2000|isbn=0-8225-2996-3|location=Minneapolis, MN|pages=[https://archive.org/details/ancientcommunica00wood/page/35 35, 36]|url=https://archive.org/details/ancientcommunica00wood/page/35}}</ref>

Three of the simple machines were studied and described by Greek philosopher [[Archimedes]] around the 3rd century BC: the lever, pulley and screw.<ref name="Asimov1988"/><ref name="Chiu">{{Citation
 |last        = Chiu
 |first       = Y. C.
 |title       = An introduction to the History of Project Management
 |publisher   = Eburon Academic Publishers
 |year        = 2010
 |location    = Delft
 |pages       = 42
 |url         = https://books.google.com/books?id=osNrPO3ivZoC&pg=PA42
 |isbn        = 978-90-5972-437-2
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20160818202910/https://books.google.com/books?id=osNrPO3ivZoC&pg=PA42
 |archive-date = 2016-08-18
}}</ref>  Archimedes discovered the principle of [[mechanical advantage]] in the lever.<ref>{{cite book |last = Ostdiek |first       = Vern |author2 = Bord, Donald |title = Inquiry into Physics |year = 2005 |publisher = Thompson Brooks/Cole |isbn = 978-0-534-49168-0 |url         = https://books.google.com/books?id=7kz2pd14hPUC&pg=PA123 |access-date  = 2008-05-22 |page = 123|url-status = live|archive-url = https://web.archive.org/web/20130528052651/http://books.google.com/books?id=7kz2pd14hPUC&pg=PA123|archive-date = 2013-05-28
}}</ref>  Later Greek philosophers defined the classic five simple machines (excluding the inclined plane) and were able to roughly calculate their mechanical advantage.<ref name="Usher"/>  [[Hero of Alexandria]] ({{circa|10}}–75 AD) in his work ''Mechanics'' lists five mechanisms that can "set a load in motion"; lever, [[windlass]], pulley, wedge, and screw,<ref name="Chiu" /> and describes their fabrication and uses.<ref>{{cite conference
 |first       = Viktor
 |last        = Strizhak
 |author2     = Igor Penkov
 |author3     = Toivo Pappel
 |title       = Evolution of design, use, and strength calculations of screw threads and threaded joints
 |book-title   = HMM2004 International Symposium on History of Machines and Mechanisms
 |publisher   = Kluwer Academic publishers
 |year        = 2004
 |url         = https://books.google.com/books?id=FqZvlMnjqY0C&q=%22archimedean+simple+machine%22
 |isbn        = 1-4020-2203-4
 |access-date  = 2008-05-21
 |page        = 245
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20130607095045/http://books.google.com/books?id=FqZvlMnjqY0C&printsec=frontcover&dq=%22archimedean+simple+machine%22&source=gbs_summary_r&cad=0
 |archive-date = 2013-06-07
}}</ref>  However, the Greeks' understanding was limited to [[statics]] (the balance of forces) and did not include [[Dynamics (mechanics)|dynamics]] (the tradeoff between force and distance) or the concept of [[Work (physics)|work]].{{Citation needed|date=May 2022}}

[[File:Agricola Stamp ore crusher.png|thumb|This ore crushing machine is powered by a water wheel.]]
The earliest practical [[wind-power]]ed machines, the [[windmill]] and [[wind pump]], first appeared in the [[Muslim world]] during the [[Islamic Golden Age]], in what are now Iran, Afghanistan, and Pakistan, by the 9th century AD.<ref>[[Ahmad Y Hassan]], [[Donald Routledge Hill]] (1986). ''Islamic Technology: An illustrated history'', p. 54. [[Cambridge University Press]]. {{ISBN|0-521-42239-6}}.</ref><ref>{{citation |first=Adam |last=Lucas |year=2006 |title=Wind, Water, Work: Ancient and Medieval Milling Technology |publisher=Brill Publishers |isbn=90-04-14649-0 |page=65}}</ref><ref>{{cite book|last1=Eldridge|first1=Frank|title=Wind Machines|date=1980|publisher=Litton Educational Publishing, Inc.|location=New York|isbn=0-442-26134-9|page=[https://archive.org/details/windmachines00fran/page/15 15]|edition=2nd|url=https://archive.org/details/windmachines00fran/page/15}}</ref><ref>{{cite book|last1=Shepherd|first1=William|title=Electricity Generation Using Wind Power|date=2011|publisher=World Scientific Publishing Co. Pte. Ltd.|location=Singapore|isbn=978-981-4304-13-9|page=4|edition=1}}</ref> The earliest practical [[steam-power]]ed machine was a [[steam jack]] driven by a [[steam turbine]], described in 1551 by [[Taqi ad-Din Muhammad ibn Ma'ruf]] in [[Ottoman Egypt]].<ref>[http://www.history-science-technology.com/Notes/Notes%201.htm Taqi al-Din and the First Steam Turbine, 1551 A.D.] {{webarchive|url=https://web.archive.org/web/20080218171045/http://www.history-science-technology.com/Notes/Notes%201.htm |date=2008-02-18 }}, web page, accessed on line 23 October 2009; this web page refers to [[Ahmad Y Hassan]] (1976), ''Taqi al-Din and Arabic Mechanical Engineering'', pp. 34–5, Institute for the History of Arabic Science, [[University of Aleppo]].</ref><ref>[[Ahmad Y. Hassan]] (1976), ''Taqi al-Din and Arabic Mechanical Engineering'', p. 34–35, Institute for the History of Arabic Science, [[University of Aleppo]]</ref>

The [[cotton gin]] was invented in India by the 6th century AD,<ref>{{cite book|ref=Lakwete|author=Lakwete, Angela|url=https://books.google.com/books?id=uOMaGVnPfBcC |title=Inventing the Cotton Gin: Machine and Myth in Antebellum America|place= Baltimore|publisher= The Johns Hopkins University Press|year= 2003|isbn=9780801873942|pages=1–6}}</ref> and the [[spinning wheel]] was invented in the [[Islamic world]] by the early 11th century,<ref name="Pacey">{{cite book | last = Pacey | first = Arnold | title = Technology in World Civilization: A Thousand-Year History | orig-year = 1990 | edition = First MIT Press paperback | year = 1991 | publisher = The MIT Press | location = Cambridge MA | pages = 23–24}}</ref> both of which were fundamental to the growth of the [[cotton industry]]. The spinning wheel was also a precursor to the [[spinning jenny]].<ref>{{cite book |last1=Žmolek |first1=Michael Andrew |title=Rethinking the Industrial Revolution: Five Centuries of Transition from Agrarian to Industrial Capitalism in England |date=2013 |publisher=BRILL |isbn=9789004251793 |page=328 |url=https://books.google.com/books?id=-RKaAAAAQBAJ&pg=PA328 |quote=The spinning jenny was basically an adaptation of its precursor the spinning wheel}}</ref>

The earliest [[Program (machine)|programmable machines]] were developed in the Muslim world. A [[music sequencer]], a programmable [[musical instrument]], was the earliest type of programmable machine. The first music sequencer was an automated [[flute]] player invented by the [[Banu Musa]] brothers, described in their ''[[Book of Ingenious Devices]]'', in the 9th century.<ref name=Koetsier>{{Citation |last1=Koetsier |first1=Teun  |year=2001 |title=On the prehistory of programmable machines: musical automata, looms, calculators |journal=Mechanism and Machine Theory |volume=36 |issue=5 |pages=589–603 |publisher=Elsevier |doi=10.1016/S0094-114X(01)00005-2 |postscript=.}}</ref><ref>{{cite journal |last1=Kapur |first1=Ajay |last2=Carnegie |first2=Dale |last3=Murphy |first3=Jim |last4=Long |first4=Jason |title=Loudspeakers Optional: A history of non-loudspeaker-based electroacoustic music |journal=[[Organised Sound]] |date=2017 |volume=22 |issue=2 |pages=195–205 |doi=10.1017/S1355771817000103 |publisher=[[Cambridge University Press]] |issn=1355-7718|doi-access=free }}</ref> In 1206, Al-Jazari invented programmable [[automata]]/[[robot]]s. He described four [[automaton]] musicians, including drummers operated by a programmable [[drum machine]], where they could be made to play different rhythms and different drum patterns.<ref name=Sharkey>Professor Noel Sharkey, [https://web.archive.org/web/20070629182810/http://www.shef.ac.uk/marcoms/eview/articles58/robot.html A 13th Century Programmable Robot (Archive)], [[University of Sheffield]].</ref>

During the [[Renaissance]], the dynamics of the ''Mechanical Powers'', as the simple machines were called, began to be studied from the standpoint of how much useful work they could perform, leading eventually to the new concept of mechanical [[work (physics)|work]]. In 1586 Flemish engineer [[Simon Stevin]] derived the mechanical advantage of the inclined plane, and it was included with the other simple machines. The complete dynamic theory of simple machines was worked out by Italian scientist [[Galileo Galilei]] in 1600 in ''Le Meccaniche'' ("On Mechanics").<ref name="Krebs">{{cite book
 |last        = Krebs
 |first       = Robert E.
 |title       = Groundbreaking Experiments, Inventions, and Discoveries of the Middle Ages
 |year        = 2004
 |publisher   = Greenwood Publishing Group
 |isbn        = 978-0-313-32433-8
 |url         = https://books.google.com/books?id=MTXdplfiz-cC&q=%22mechanics+Galileo+analyzed%22&pg=PA163
 |access-date  = 2008-05-21
 |page        = 163
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20130528045000/http://books.google.com/books?id=MTXdplfiz-cC&pg=PA163&dq=%22mechanics+Galileo+analyzed%22#v=onepage&q=%22mechanics%20Galileo%20analyzed%22&f=false
 |archive-date = 2013-05-28
}}</ref><ref name="Stephen">{{cite book
 |last        = Stephen
 |first       = Donald
 |author2     = Lowell Cardwell
 |title       = Wheels, clocks, and rockets: a history of technology
 |publisher   = W. W. Norton & Company
 |year        = 2001
 |location    = USA
 |pages       = 85–87
 |url         = https://books.google.com/books?id=BSfpFLV1nkAC&q=%22simple+machine%22+galileo&pg=PA86
 |isbn        = 978-0-393-32175-3
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20160818204648/https://books.google.com/books?id=BSfpFLV1nkAC&pg=PA86&dq=%22simple+machine%22+galileo#v=onepage&q=%22simple%20machine%22%20galileo&f=false
 |archive-date = 2016-08-18
}}</ref> He was the first to understand that simple machines do not create [[energy]], they merely transform it.<ref name="Krebs" />

The classic rules of sliding [[friction]] in machines were discovered by [[Leonardo da Vinci]] (1452–1519), but remained unpublished in his notebooks. They were rediscovered by [[Guillaume Amontons]] (1699) and were further developed by [[Charles-Augustin de Coulomb]] (1785).<ref>{{cite book
 |last        = Armstrong-Hélouvry
 |first       = Brian
 |title       = Control of machines with friction
 |publisher   = Springer
 |year        = 1991
 |location    = USA
 |pages       = 10
 |url         = https://books.google.com/books?id=0zk_zI3xACgC&pg=PA10
 |isbn        = 978-0-7923-9133-3
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20160818141554/https://books.google.com/books?id=0zk_zI3xACgC&pg=PA10
 |archive-date = 2016-08-18
}}</ref>

[[James Watt]] patented his [[parallel motion]] linkage in 1782, which made the double acting steam engine practical.<ref>Pennock, G. R., James Watt (1736-1819), ''Distinguished Figures in Mechanism and Machine Science,'' ed. M. Ceccarelli, Springer, 2007, {{ISBN|978-1-4020-6365-7}} (Print) 978-1-4020-6366-4 (Online).</ref> The [[Boulton and Watt]] steam engine and later designs powered [[steam locomotive]]s, [[marine steam engine|steam ships]], and [[steam power|factories]].

[[File:Bonsack machine.png|thumb|alt=Bonsack's machine|James Albert Bonsack's cigarette rolling machine was invented in 1880 and patented in 1881.]]
The [[Industrial Revolution]] was a period from 1750 to 1850 where changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times. It began in the [[United Kingdom]], then subsequently spread throughout [[Western Europe]], [[North America]], [[Japan]], and eventually the rest of the world.

Starting in the later part of the 18th century, there began a transition in parts of [[Great Britain]]'s previously manual labour and draft-animal-based economy towards machine-based manufacturing. It started with the mechanisation of the textile industries, the development of [[iron-making]] techniques and the increased use of [[coke (fuel)|refined coal]].<ref name="World History: Patterns of Interaction"/>

== Simple machines ==
{{main|Simple machine}}
[[File:Table of Mechanicks, Cyclopaedia, Volume 2.png|thumb|''[[Chambers' Cyclopædia]]'' (1728) has a table of simple mechanisms.<ref name="Mechanicks">{{Citation |last=Chambers |first=Ephraim |year=1728 |title=Table of Mechanicks |work=Cyclopaedia, A Useful Dictionary of Arts and Sciences |volume=2 |location=London, England |page=528, Plate 11 }}.</ref> Simple machines provide a "vocabulary" for understanding more complex machines.]]

The idea that a machine can be decomposed into simple movable elements led [[Archimedes]] to define the [[lever]], [[pulley]] and [[screw]] as [[simple machines]]. By the time of the Renaissance this list increased to include the [[wheel and axle]], [[Wedge (mechanical device)|wedge]] and [[inclined plane]]. The modern approach to characterizing machines focusses on the components that allow movement, known as [[joint (mechanics)|joints]].

Wedge (hand axe): Perhaps the first example of a device designed to manage power is the [[hand axe]], also called [[biface]] and [[Olorgesailie]]. A hand axe is made by chipping stone, generally flint, to form a bifacial edge, or [[wedge (mechanical device)|wedge]]. A wedge is a simple machine that transforms lateral force and movement of the tool into a transverse splitting force and movement of the workpiece. The available power is limited by the effort of the person using the tool, but because power is the product of force and movement, the wedge amplifies the force by reducing the movement. This amplification, or [[mechanical advantage]] is the ratio of the input speed to output speed.  For a wedge this is given by 1/tanα, where α is the tip angle. The faces of a wedge are modeled as straight lines to form a sliding or [[prismatic joint]].

Lever: The [[lever]] is another important and simple device for managing power. This is a body that pivots on a fulcrum. Because the velocity of a point farther from the pivot is greater than the velocity of a point near the pivot, forces applied far from the pivot are amplified near the pivot by the associated decrease in speed. If ''a'' is the distance from the pivot to the point where the input force is applied and ''b'' is the distance to the point where the output force is applied, then ''a/b'' is the [[mechanical advantage]] of the lever. The fulcrum of a lever is modeled as a hinged or [[revolute joint]].

Wheel: The [[wheel]] is an important early machine, such as the [[chariot]]. A wheel uses the law of the lever to reduce the force needed to overcome [[friction]] when pulling a load. To see this notice that the friction associated with pulling a load on the ground is approximately the same as the friction in a simple bearing that supports the load on the axle of a wheel. However, the wheel forms a lever that magnifies the pulling force so that it overcomes the frictional resistance in the bearing.

[[File:Kinematics of Machinery - Figure 21.jpg|thumb|right|alt=Illustration of a Four-bar linkage from Kinematics of Machinery, 1876|[[s:The Kinematics of Machinery|''The Kinematics of Machinery'' (1876)]] has an illustration of a [[four-bar linkage]].]]
The classification of [[simple machine]]s to provide a strategy for the design of new machines was developed by [[Franz Reuleaux]], who collected and studied over 800 elementary machines.<ref>[[Francis C. Moon|Moon, F. C.]], [https://kmoddl.library.cornell.edu/facets/moon61899.htm The Reuleaux Collection of Kinematic Mechanisms at Cornell University, 1999] {{webarchive|url=https://web.archive.org/web/20150518064706/http://kmoddl.library.cornell.edu/facets/moon61899.htm |date=2015-05-18 }}</ref> He recognized that the classical [[simple machine]]s can be separated into the lever, pulley and wheel and axle that are formed by a body rotating about a hinge, and the inclined plane, wedge and screw that are similarly a block sliding on a flat surface.<ref>Hartenberg, R.S. & J. Denavit (1964) [https://kmoddl.library.cornell.edu/bib.php?m=23 Kinematic synthesis of linkages] {{webarchive|url=https://web.archive.org/web/20110519063139/http://kmoddl.library.cornell.edu/bib.php?m=23 |date=2011-05-19 }}, New York: McGraw-Hill, online link from [[Cornell University]].</ref>

Simple machines are elementary examples of [[kinematic chain]]s or [[linkage (mechanical)|linkages]] that are used to model [[mechanical systems]] ranging from the steam engine to robot manipulators. The bearings that form the fulcrum of a lever and that allow the wheel and axle and pulleys to rotate are examples of a [[kinematic pair]] called a hinged joint. Similarly, the flat surface of an inclined plane and wedge are examples of the [[kinematic pair]] called a sliding joint. The screw is usually identified as its own kinematic pair called a helical joint.

This realization shows that it is the joints, or the connections that provide movement, that are the primary elements of a machine. Starting with four types of joints, the rotary joint, sliding joint, cam joint and gear joint, and related connections such as cables and belts, it is possible to understand a machine as an assembly of solid parts that connect these joints called a [[mechanism (engineering)|mechanism]].<ref name="Uicker2003"/>

Two levers, or cranks, are combined into a planar [[four-bar linkage]] by attaching a link that connects the output of one crank to the input of another. Additional links can be attached to form a [[six-bar linkage]] or in series to form a robot.<ref name="Uicker2003"/>

==Mechanical systems==
[[File:SteamEngine Boulton&Watt 1784.png|thumb|upright=1.2|alt=Boulton & Watt Steam Engine|The Boulton & Watt Steam Engine, 1784]]  
A '''mechanical system''' manages [[power (physics)|power]] to accomplish a task that involves forces and movement. Modern machines are systems consisting of (i) a power source and [[actuator]]s that generate forces and movement, (ii) a [[Machine (mechanical)|system of mechanisms]] that shape the actuator input to achieve a specific application of output forces and movement, (iii) a controller with sensors that compare the output to a performance goal and then directs the actuator input, and (iv) an interface to an operator consisting of levers, switches, and displays. This can be seen in Watt's steam engine in which the power is provided by steam expanding to drive the piston. The walking beam, coupler and crank transform the linear movement of the piston into rotation of the output pulley. Finally, the pulley rotation drives the flyball governor which controls the valve for the steam input to the piston cylinder.

The adjective "mechanical" refers to skill in the practical application of an art or science, as well as relating to or caused by movement, physical forces, properties or agents such as is dealt with by [[mechanics]].<ref name=OED>{{cite OED|mechanical}}</ref> Similarly Merriam-Webster Dictionary<ref name=Merriam-mechanical>Merriam-Webster Dictionary [http://www.merriam-webster.com/dictionary/mechanical Definition of mechanical] {{webarchive|url=https://web.archive.org/web/20111020103442/http://www.merriam-webster.com/dictionary/mechanical |date=2011-10-20 }}</ref> defines "mechanical" as relating to machinery or tools.

Power flow through a machine provides a way to understand the performance of devices ranging from levers and gear trains to automobiles and robotic systems. The German mechanician [[Franz Reuleaux]]<ref name=Reuleaux1876>Reuleaux, F., 1876 [https://archive.org/details/kinematicsmachi01reulgoog <!-- quote=kinematics of machinery. --> ''The Kinematics of Machinery''] {{webarchive|url=https://web.archive.org/web/20130602121819/http://books.google.com/books?id=WUZVAAAAMAAJ&printsec=frontcover&dq=kinematics+of+machinery&hl=en&sa=X&ei=qpn4Tse-E9SasgLcsZytDw&ved=0CEQQ6AEwAQ |date=2013-06-02 }} (trans. and annotated by A. B. W. Kennedy), reprinted by Dover, New York (1963)</ref> wrote, "a machine is a combination of resistant bodies so arranged that by their means the mechanical forces of nature can be compelled to do work accompanied by certain determinate motion." Notice that forces and motion combine to define [[Power (physics)|power]].

More recently, Uicker et al.<ref name=Uicker2003>J. J. Uicker, G. R. Pennock, and J. E. Shigley, 2003, ''Theory of Machines and Mechanisms'', Oxford University Press, New York.</ref> stated that a machine is "a device for applying power or changing its direction."McCarthy and Soh<ref name=McCarthy2010>J. M. McCarthy and G. S. Soh, 2010, [https://books.google.com/books?id=jv9mQyjRIw4C&pg=PA231 ''Geometric Design of Linkages,''] {{webarchive|url=https://web.archive.org/web/20160819020038/https://books.google.com/books?id=jv9mQyjRIw4C&pg=PA231 |date=2016-08-19 }} Springer, New York.</ref> describe a machine as a system that "generally consists of a power source and a [[mechanism (engineering)|mechanism]] for the controlled use of this power."

== Power sources ==
{{More citations needed|section|date=November 2021}}
[[File:Model Engine Luc Viatour.jpg|thumb|Diesel engine, friction clutch and gear transmission of an automobile]]
[[File:Generator-20071117.jpg|thumb|Early [[Ganz]] Electric Generator in [[Zwevegem]], [[West Flanders]], [[Belgium]]]]
Human and animal effort were the original power sources for early machines.{{citation needed|date=November 2021}}

'''Waterwheel:''' [[Waterwheel]]s appeared around the world around 300 BC to use flowing water to generate rotary motion, which was applied to [[watermill|milling grain, and powering lumber, machining and textile operations]]. Modern [[water turbine]]s use water flowing through a [[dam]] to drive an [[electric generator]].

'''Windmill:''' Early [[wind mill|windmills]] captured wind power to generate rotary motion for milling operations. Modern [[wind turbine]]s also drives a generator. This electricity in turn is used to drive [[Electric motor|motors]] forming the actuators of mechanical systems.

'''Engine:''' The word engine derives from "ingenuity" and originally referred to contrivances that may or may not be physical devices.<ref>[http://www.merriam-webster.com/dictionary/engine Merriam-Webster's definition of engine]</ref> A [[steam engine]] uses heat to boil water contained in a pressure vessel; the expanding steam drives a piston or a turbine. This principle can be seen in the [[aeolipile]] of Hero of Alexandria. This is called an [[external combustion engine]].

An [[automobile]] engine is called an [[internal combustion engine]] because it burns fuel (an [[exothermic]] chemical reaction) inside a cylinder and uses the expanding gases to drive a [[piston]]. A [[jet engine]] uses a turbine to compress air which is burned with fuel so that it expands through a nozzle to provide thrust to an [[aircraft]], and so is also an "internal combustion engine."<ref>"Internal combustion engine", ''Concise Encyclopedia of Science and Technology'', Third Edition, Sybil P. Parker, ed. McGraw-Hill, Inc., 1994, p. 998 .</ref>

'''Power plant:''' The heat from coal and natural gas combustion in a [[boiler]] generates steam that drives a [[steam turbine]] to rotate an [[electric generator]]. A [[nuclear power plant]] uses heat from a [[nuclear reactor]] to generate steam and [[electric power]]. This power is distributed through a [[electrical grid|network of transmission lines]] for industrial and individual use.

'''Motors:''' [[Electric motor]]s use either [[alternating current|AC]] or [[direct current|DC]] electric current to generate rotational movement. Electric [[servomechanism|servomotors]] are the actuators for mechanical systems ranging from [[robotics|robotic systems]] to [[fly-by-wire|modern aircraft]].

'''Fluid Power:''' [[hydraulic cylinder|Hydraulic]] and [[pneumatic cylinder|pneumatic]] systems use electrically driven [[pump]]s to drive water or air respectively into cylinders to power [[linear actuator|linear movement]].

'''Electrochemical:''' Chemicals and materials can also be sources of power.<ref>{{Cite book|last1=Brett|first1=Christopher M. A|title=Electrochemistry: principles, methods, and applications|last2=Brett|first2=Ana Maria Oliveira|date=1993|publisher=Oxford University Press|isbn=978-0-19-855389-2|location=Oxford; New York|language=English|oclc=26398887}}</ref> They may chemically deplete or need re-charging, as is the case with [[Electric battery|batteries]],<ref name=":0">{{Cite book|last=Crompton|first=T. R.|url=https://books.google.com/books?id=QmVR7qiB5AUC&q=battery+one+or+more+cells&pg=PA11|title=Battery Reference Book|date=2000-03-20|publisher=Elsevier|isbn=978-0-08-049995-6|language=en}}</ref> or they may produce power without changing their state, which is the case for [[solar cell]]s and [[thermoelectric generator]]s.<ref name=":1">{{Cite web|title=Solar Cells -- Performance And Use|url=http://solarbotics.net/starting/200202_solar_cells/200202_solar_cell_use.html|access-date=|website=}}</ref><ref name=":2">{{Cite journal|last1=Fernández-Yáñez|first1=P.|last2=Romero|first2=V.|last3=Armas|first3=O.|last4=Cerretti|first4=G.|date=2021-09-01|title=Thermal management of thermoelectric generators for waste energy recovery|journal=Applied Thermal Engineering|language=en|volume=196|article-number=117291|doi=10.1016/j.applthermaleng.2021.117291|issn=1359-4311|doi-access=free|bibcode=2021AppTE.19617291F }}</ref> All of these, however, still require their energy to come from elsewhere. With batteries, it is the already existing [[Chemical energy|chemical potential energy]] inside.<ref name=":0" /> In solar cells and thermoelectrics, the energy source is light and heat respectively.<ref name=":1" /><ref name=":2" />

== Mechanisms ==
The ''mechanism'' of a mechanical system is assembled from components called ''[[machine element]]s''. These elements provide structure for the system and control its movement.

The structural components are, generally, the frame members, bearings, splines, springs, seals, [[fastener]]s and covers. The shape, texture and color of covers provide a [[industrial design|styling and operational interface]] between the mechanical system and its users.

The assemblies that control movement are also called "[[mechanism (engineering)|mechanisms]]."<ref name="Reuleaux1876" /><ref name="Uicker2003"/> Mechanisms are generally classified as [[gear]]s and [[gear train]]s, which includes [[belt drive]]s and [[chain drive]]s, [[Cam (mechanism)|cam]] and [[cam follower|follower]] mechanisms, and [[linkage (mechanical)|linkages]], though there are other special mechanisms such as clamping linkages, [[Geneva drive|indexing mechanisms]], [[escapement]]s and friction devices such as [[brake]]s and [[clutch]]es.

The number of degrees of freedom of a mechanism, or its mobility, depends on the number of links and joints and the types of joints used to construct the mechanism. The general mobility of a mechanism is the difference between the unconstrained freedom of the links and the number of constraints imposed by the joints. It is described by the [[Chebychev–Grübler–Kutzbach criterion]].

=== Gears and gear trains ===
[[File:Antikythera Fragment A (Front).webp|thumb|The [[Antikythera mechanism]] (main fragment)]]
The transmission of rotation between contacting toothed wheels can be traced back to the [[Antikythera mechanism]] of Greece and the [[south-pointing chariot]] of [[China]]. Illustrations by the renaissance scientist [[Georgius Agricola]] show gear trains with cylindrical teeth. The implementation of the [[involute gear|involute tooth]] yielded a standard gear design that provides a constant speed ratio. Some important features of gears and gear trains are:
* The ratio of the pitch circles of mating gears defines the [[gear ratio|speed ratio]] and the [[mechanical advantage]] of the gear set.
*  A [[epicyclic gearing|planetary gear train]] provides high gear reduction in a compact package.
*  It is possible to design gear teeth for gears that are [[non-circular gear|non-circular]], yet still transmit torque smoothly.
* The speed ratios of [[chain drive|chain]] and [[belt (mechanical)|belt drives]] are computed in the same way as gear ratios. See [[bicycle gearing]].

=== Cam and follower mechanisms ===
A [[Cam (mechanism)|cam]] and [[cam follower|follower]] is formed by the direct contact of two specially shaped links. The driving link is called the cam (also see [[camshaft|cam shaft]]) and the link that is driven through the direct contact of their surfaces is called the follower. The shape of the contacting surfaces of the [[Cam (mechanism)|cam]] and [[cam follower|follower]] determines the movement of the mechanism.

=== Linkages ===
[[File:Landing gear schematic.svg|thumb|right|Schematic of the actuator and four-bar linkage that position an aircraft landing gear]]
A [[linkage (mechanical)|linkage]] is a collection of links connected by joints. Generally, the links are the structural elements and the joints allow movement. Perhaps the single most useful example is the planar [[four-bar linkage]]. However, there are many more special linkages:
* [[Watt's linkage]] is a four-bar linkage that generates an approximate straight line. It was critical to the operation of his design for the steam engine. This linkage also appears in vehicle suspensions to prevent side-to-side movement of the body relative to the wheels. Also see the article [[Parallel motion]].
* The success of Watt's linkage lead to the design of similar approximate straight-line linkages, such as [[Hoekens linkage|Hoeken's linkage]] and [[Chebyshev linkage|Chebyshev's linkage]].
* The [[Peaucellier-Lipkin linkage|Peaucellier linkage]] generates a true straight-line output from a rotary input.
* The [[Sarrus linkage]] is a spatial linkage that generates straight-line movement from a rotary input.
* The [[Klann linkage]] and the [[Theo Jansen|Jansen linkage]] are recent inventions that provide interesting walking movements. They are respectively a six-bar and an eight-bar linkage.

===Planar mechanism===
A planar mechanism is a mechanical system that is constrained so the trajectories of points in all the bodies of the system lie on planes parallel to a ground plane. The rotational axes of hinged joints that connect the bodies in the system are perpendicular to this ground plane.

===Spherical mechanism===
A '''spherical mechanism''' is a mechanical system in which the bodies move in a way that the trajectories of points in the system lie on concentric spheres. The rotational axes of hinged joints that connect the bodies in the system pass through the center of these circle.

===Spatial mechanism===
A '''spatial mechanism''' is a mechanical system that has at least one body that moves in a way that its point trajectories are general space curves. The rotational axes of hinged joints that connect the bodies in the system form lines in space that do not intersect and have distinct common normals.

=== Flexure mechanisms ===
A flexure mechanism consists of a series of rigid bodies connected by compliant elements (also known as flexure joints) that is designed to produce a geometrically well-defined motion upon application of a force.

==Machine elements==
The elementary mechanical components of a machine are termed '''[[machine element]]s'''. These elements consist of three basic types (i) ''structural components'' such as frame members, bearings, axles, splines, [[fastener]]s, seals, and lubricants, (ii) ''[[Mechanism (engineering)|mechanisms]]'' that control movement in various ways such as [[gear train]]s, [[belt (mechanical)|belt]] or [[chain drive]]s, [[Linkage (mechanical)|linkages]], [[Cam (mechanism)|cam]] and [[cam follower|follower]] systems, including [[brake]]s and [[clutch]]es, and (iii) ''control components'' such as buttons, switches, indicators, sensors, actuators and computer controllers.<ref>Robert L. Norton, ''Machine Design,'' (4th Edition), Prentice-Hall, 2010</ref> While generally not considered to be a machine element, the shape, texture and color of covers are an important part of a machine that provide a [[industrial design|styling and operational interface]] between the mechanical components of a machine and its users.

===Structural components===
A number of machine elements provide important structural functions such as the frame, bearings, splines, spring and seals.
* The recognition that the frame of a mechanism is an important machine element changed the name [[three-bar linkage]] into [[four-bar linkage]]. Frames are generally assembled from [[truss]] or [[beam (structure)|beam]] elements.
* [[bearing (mechanical)|Bearings]] are components designed to manage the interface between moving elements and are the source of [[friction]] in machines. In general, bearings are designed for pure rotation or [[linear-motion bearing|straight line movement]].
* [[Spline (mechanical)|Splines]] and [[key (engineering)|keys]] are two ways to reliably mount an [[axle]] to a wheel, pulley or gear so that torque can be transferred through the connection.
* [[spring (device)|Springs]] provides forces that can either hold components of a machine in place or acts as a [[suspension (vehicle)|suspension]] to support part of a machine.
* [[seal (mechanical)|Seals]] are used between mating parts of a machine to ensure fluids, such as water, hot gases, or lubricant do not leak between the mating surfaces.
* [[Fastener]]s such as [[screw]]s, bolts, spring clips, and [[rivet]]s are critical to the assembly of components of a machine. Fasteners are generally considered to be removable. In contrast, joining methods, such as [[welding]], [[soldering]], [[crimp (joining)|crimping]] and the application of [[adhesive]]s, usually require cutting the parts to disassemble the components

== Controllers ==
Controllers combine [[sensor]]s, [[logic]], and [[actuator]]s to maintain the performance of components of a machine. Perhaps the best known is the [[centrifugal governor|flyball governor]] for a steam engine. Examples of these devices range from a [[thermostat]] that as temperature rises opens a valve to cooling water to speed controllers such as the [[cruise control]] system in an automobile. The [[programmable logic controller]] replaced relays and specialized control mechanisms with a programmable computer. [[Servomotor]]s that accurately position a shaft in response to an electrical command are the actuators that make [[robot|robotic systems]] possible.

== Computing machines ==
[[File:Arithmometre%2C designed by Charles Xavier Thomas%2C c. 1820%2C for the four rules of arithmetic%2C manufactured 1866-1870 AD%2C TM10901 - Tekniska museet - Stockholm%2C Sweden - DSC01567.JPG|right|thumb|alt=Arithmometr computing machine|The arithmometre was designed by Charles Xavier Thomas, {{circa|1820}}, for the four rules of arithmetic. It was manufactured 1866–1870 AD and exhibited in the Tekniska museet, Stockholm, Sweden.]]
[[Charles Babbage]] designed machines to tabulate logarithms and other functions in 1837. His [[Difference engine]] can be considered an advanced [[mechanical calculator]] and his [[Analytical Engine]] a forerunner of the modern [[computer]], though none of the larger designs were completed in Babbage's lifetime.

The [[Arithmometer]] and the [[Comptometer]] are mechanical computers that are precursors to [[Computer|modern digital computers]]. Models used to study modern computers are termed [[Finite-state machine|State machine]] and [[Turing machine]].

== Molecular machines ==
[[File:Protein translation.gif|thumb|A [[ribosome]] is a [[biological machine]] that utilizes [[protein dynamics]].]]
The biological molecule [[myosin]] reacts to ATP and ADP to alternately engage with an actin filament and change its shape in a way that exerts a force, and then disengage to reset its shape, or conformation. This acts as the molecular drive that causes muscle contraction. Similarly the biological molecule [[kinesin]] has two sections that alternately engage and disengage with microtubules causing the molecule to move along the microtubule and transport vesicles within the cell, and [[dynein]], which moves cargo inside cells towards the nucleus and produces the axonemal beating of [[cilia#Motile cilia|motile cilia]] and [[flagella]]. "In effect, the motile cilium is a nanomachine composed of perhaps over 600 proteins in molecular complexes, many of which also function independently as nanomachines. [[Flexible linker]]s allow the [[Protein domain#Domains and protein flexibility|mobile protein domains]] connected by them to recruit their binding partners and induce long-range [[allostery]] via [[Protein dynamics#Global flexibility: multiple domains|protein domain dynamics]]. "<ref name="Satir2008">{{cite journal
  | last = Satir
  | first = Peter
  |author2=Søren T. Christensen
  | title = Structure and function of mammalian cilia
  | journal = Histochemistry and Cell Biology
  | volume = 129
  | issue = 6
  | pages = 687–93
  | date = 2008-03-26
  | doi = 10.1007/s00418-008-0416-9
  | id = 1432-119X 
  | pmid = 18365235
  | pmc = 2386530 }}</ref> Other biological machines are responsible for energy production, for example [[ATP synthase]] which harnesses energy from [[Proton-motive force|proton gradients across membranes]] to drive a turbine-like motion used to synthesise [[Adenosine triphosphate|ATP]], the energy currency of a cell.<ref>{{Cite journal|last1=Kinbara|first1=Kazushi|last2=Aida|first2=Takuzo|date=2005-04-01|title=Toward Intelligent Molecular Machines: Directed Motions of Biological and Artificial Molecules and Assemblies|journal=Chemical Reviews|volume=105|issue=4|pages=1377–1400|doi=10.1021/cr030071r|pmid=15826015|issn=0009-2665}}</ref> Still other machines are responsible for [[gene expression]], including [[DNA polymerase]]s for replicating [[DNA]],{{citation needed|date=December 2018}} [[RNA polymerase]]s for producing [[Messenger RNA|mRNA]],{{citation needed|date=December 2018}} the [[spliceosome]] for removing [[intron]]s, and the [[ribosome]] for [[Protein synthesis|synthesising proteins]]. These machines and their [[protein dynamics|nanoscale dynamics]] are far more complex than any [[molecular machine]]s that have yet been artificially constructed.<ref name="pmid21570668">{{cite book |vauthors=Bu Z, Callaway DJ |title=Protein Structure and Diseases |chapter=Proteins MOVE! Protein dynamics and long-range allostery in cell signaling |volume=83 |pages=163–221 |year=2011 |pmid=21570668 |doi=10.1016/B978-0-12-381262-9.00005-7|series=Advances in Protein Chemistry and Structural Biology |isbn=9780123812629}}</ref> These molecules are increasingly considered to be [[nanomachines]].{{citation needed|date=December 2018}}

Researchers have used DNA to construct nano-dimensioned [[four-bar linkage]]s.<ref>[http://www.pnas.org/content/112/3/713.abstract Marras, A., Zhou, L., Su, H., and Castro, C.E. Programmable motion of DNA origami mechanisms, Proceedings of the National Academy of Sciences, 2015] {{webarchive|url=https://web.archive.org/web/20170804052839/http://www.pnas.org/content/112/3/713.abstract |date=2017-08-04 }}</ref><ref>[http://mechanicaldesign101.com/2014/10/21/haijun-su-draft-article/ McCarthy, C, DNA Origami Mechanisms and Machines | Mechanical Design 101, 2014] {{webarchive|url=https://web.archive.org/web/20170918021917/http://mechanicaldesign101.com/2014/10/21/haijun-su-draft-article/ |date=2017-09-18 }}
</ref>

==Impact==
===Mechanization and automation===
{{main article|Mechanization|Automation}}
[[File:Agricola1.jpg|thumb|right|This water-powered [[Hoist (device)#Mine hoists|mine hoist]] was used for raising ore. This woodblock is from ''[[De re metallica]]'' by Georg Bauer (Latinized name [[Georgius Agricola]], {{circa|1555}}), an early mining textbook that contains numerous drawings and descriptions of mining equipment.]]
Mechanization (or mechanisation in [[British English|BE]]) is providing human operators with machinery that assists them with the muscular requirements of work or displaces muscular work. In some fields, mechanization includes the use of hand tools. In modern usage, such as in engineering or economics, mechanization implies machinery more complex than hand tools and would not include simple devices such as an un-geared horse or donkey mill. Devices that cause speed changes or changes to or from reciprocating to rotary motion, using means such as [[gear]]s, [[pulley]]s or [[line shaft|sheaves]] and belts, [[drive shaft|shafts]], [[Cam (mechanism)|cam]]s and [[Crank (mechanism)|cranks]], usually are considered machines. After electrification, when most small machinery was no longer hand powered, mechanization was synonymous with motorized machines.<ref>Jerome (1934) gives the industry classification of machine tools as being "other than hand power".  Beginning with the 1900 U.S. census, power use was part of the definition of a factory, distinguishing it from a workshop.</ref>

Automation is the use of [[control system]]s and [[information technology|information technologies]] to reduce the need for human work in the production of goods and services. In the scope of [[industrialization]], automation is a step beyond [[mechanization]]. Whereas mechanization provides human operators with machinery to assist them with the muscular requirements of work, automation greatly decreases the need for human sensory and mental requirements as well. Automation plays an increasingly important role in the [[world economy]] and in daily experience.

===Automata===
{{main article|Automaton}}
An automaton (plural: automata or automatons) is a self-operating machine. The word is sometimes used to describe a [[robot]], more specifically an [[autonomous robot]]. A ''Toy Automaton'' was patented in 1863.<ref>{{Cite web| url=https://patents.google.com/patent/US40891 | title=U.S. Patent and Trademark Office, Patent# 40891, ''Toy Automaton'' | publisher=[[Google Patents]] | access-date=2007-01-07 }}</ref>

== Mechanics ==
Usher<ref>A. P. Usher, 1929, [https://books.google.com/books?id=xuDDqqa8FlwC&q=history+of+mechanical+inventions ''A History of Mechanical Inventions''] {{webarchive|url=https://web.archive.org/web/20130602124007/http://books.google.com/books?id=xuDDqqa8FlwC&printsec=frontcover&dq=history+of+mechanical+inventions&hl=en&sa=X&ei=n5r4Tov7HaqPsQLugvWuAQ&ved=0CD8Q6AEwAA |date=2013-06-02 }}, Harvard University Press (reprinted by Dover Publications 1968).</ref> reports that [[Hero of Alexandria|Hero of Alexandria's]] treatise on ''Mechanics'' focussed on the study of lifting heavy weights. Today [[mechanics]] refers to the mathematical analysis of the forces and movement of a mechanical system, and consists of the study of the [[kinematics]] and [[analytical dynamics|dynamics]] of these systems.

===Dynamics of machines===
The [[rigid-body dynamics|dynamic analysis]] of machines begins with a rigid-body model to determine reactions at the bearings, at which point the elasticity effects are included. The [[rigid-body dynamics]] studies the movement of systems of interconnected bodies under the action of external forces. The assumption that the bodies are rigid, which means that they do not deform under the action of applied forces, simplifies the analysis by reducing the parameters that describe the configuration of the system to the translation and rotation of reference frames attached to each body.<ref>B. Paul, Kinematics and Dynamics of Planar Machinery, Prentice-Hall, NJ, 1979</ref><ref>L. W. Tsai, Robot Analysis: The mechanics of serial and parallel manipulators, John-Wiley, NY, 1999.</ref>

The dynamics of a rigid body system is defined by its [[equations of motion]], which are derived using either [[Newtons laws of motion]] or [[Lagrangian mechanics]]. The solution of these equations of motion defines how the configuration of the system of rigid bodies changes as a function of time. The formulation and solution of rigid body dynamics is an important tool in the computer simulation of [[mechanical systems]].

=== Kinematics of machines ===
The dynamic analysis of a machine requires the determination of the movement, or [[kinematics]], of its component parts, known as kinematic analysis. The assumption that the system is an assembly of rigid components allows rotational and translational movement to be modeled mathematically as [[rigid transformation|Euclidean, or rigid, transformations]]. This allows the position, velocity and acceleration of all points in a component to be determined from these properties for a reference point, and the angular position, [[angular velocity]] and [[angular acceleration]] of the component.

== Machine design ==
Machine design refers to the procedures and techniques used to address the three phases of a [[product lifecycle management|machine's lifecycle]]:
# invention, which involves the identification of a need, development of requirements, concept generation, prototype development, manufacturing, and verification testing;
# performance engineering involves enhancing manufacturing efficiency, reducing service and maintenance demands, adding features and improving effectiveness, and validation testing;
# recycle is the decommissioning and disposal phase and includes recovery and reuse of materials and components.

==See also==
{{Main article|Outline of machines|Outline of industrial machinery}}
* [[Automaton]]
* [[Gear train]]
* [[History of technology]]
* [[Linkage (mechanical)]]
* [[List of mechanical, electrical and electronic equipment manufacturing companies by revenue]]
* [[Mechanism (engineering)]]
* [[Mechanical advantage]]
* [[Outline of automation]]
* [[Outline of machines]]
* [[Power (physics)]]
* [[Simple machines]]
* [[Technology]]
* [[Virtual work]]
* [[Work (physics)]]

==References==
{{Reflist|refs=
<ref name="World History: Patterns of Interaction">{{cite book |last= Beck B. |first= Roger |title= World History: Patterns of Interaction |publisher= McDougal Littell |year= 1999 |location= Evanston, Illinois }}</ref>

<ref name="Asimov1988">{{Citation |last=Asimov |first=Isaac |title=Understanding Physics |year=1988 |publisher=Barnes & Noble |location=New York, New York, USA |isbn=978-0-88029-251-1 |url=https://books.google.com/books?id=pSKvaLV6zkcC&pg=PA88 |page=88 |postscript=. |url-status=live |archive-url=https://web.archive.org/web/20160818203229/https://books.google.com/books?id=pSKvaLV6zkcC&pg=PA88 |archive-date=2016-08-18 }}</ref>
}}

==Further reading==
* {{cite book
 | first = Erik
 | last = Oberg
 |author2=Franklin D. Jones |author3=Holbrook L. Horton |author4=Henry H. Ryffel
  | year = 2000
 | title = Machinery's Handbook
 | editor1= Christopher J. McCauley |editor2=Riccardo Heald |editor3=Muhammed Iqbal Hussain
 | edition = 26th
 | publisher = Industrial Press Inc.
 | location = New York
 | isbn = 978-0-8311-2635-3
| title-link = Machinery's Handbook
 }}
* {{cite book
 | first = Franz
 | last = Reuleaux
 | others = Trans. and annotated by A. B. W. Kennedy
 | year = 1876
 | title = The Kinematics of Machinery
 | publisher = reprinted by Dover (1963)
 | location = New York
}}
* {{cite book
 | first = J. J.
 | last = Uicker |author2=G. R. Pennock |author3=J. E. Shigley
 | year = 2003
 | title = Theory of Machines and Mechanisms
 | publisher = Oxford University Press
 | location = New York
}}

*{{cite book
 | first = Erik
 | last = Oberg
 |author2=Franklin D. Jones |author3=Holbrook L. Horton |author4=Henry H. Ryffel
  | year = 2000
 | title = Machinery's Handbook
 | editor = Christopher J. McCauley |editor2=Riccardo Heald |editor3=Muhammed Iqbal Hussain
 | edition = 30th
 | publisher = Industrial Press Inc.
 | location = New York
 | isbn = 9780831130992
}}

==External links==
* {{Commons category-inline|Machines}}
* {{Wikiquote-inline}}
* [https://kmoddl.library.cornell.edu/model.php?m=reuleaux Reuleaux Collection of Mechanisms and Machines] – Cornell University
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{{Machines}}
{{Technology topics}}
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[[Category:Machines| ]]