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A machine manages power to accomplish a task. Examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work. A simple machine is a device that transforms the direction or magnitude of a force.

The word "machine" is derived from the Latin word machina,^[1] which in turn derives from the Doric Greek μαχανά (machana), Ionic Greek μηχανή (mechane) "contrivance, machine, engine"^[2] and that from μῆχος (mechos), "means, expedient, remedy".^[3]

The meaning of machine is traced by the Oxford English Dictionary^[4] to an independently functioning structure and by Merriam-Webster Dictionary^[5] to something that has been constructed. This includes human design into the meaning of machine.

Historically, a device required moving parts to classify as a machine; however, the advent of electronics technology has led to the development of devices without moving parts that many refer to as machines, such as a computer, radio, and television.^[1]

History

Perhaps the first example of a human made device designed to manage power is the hand axe, made by chipping flint to form a 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 lever is perhaps the first machine to be analysed mathematically; Archimedes provided the first known description of the principle of the lever.

Types

Mechanical

Simple machines

The idea that a machine can be broken down 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 and inclined plane.

Engines

An engine or motor is a machine designed to convert energy into useful mechanical motion.^[6]^[7] Heat engines, including internal combustion engines and external combustion engines (such as steam engines) burn a fuel to create heat which is then used to create motion. Electric motors convert electrical energy into mechanical motion, pneumatic motors use compressed air and others, such as wind-up toys use elastic energy. In biological systems, molecular motors like myosins in muscles use chemical energy to create motion.

Computing machines

Computers store and manipulate the flow of electrons, with patterns in this storage and flow being interpreted as information manipulation. See State machine and Turing machine.

Charles Babbage designed various machines to tabulate logarithms and other functions in 1837. His Difference engine is the first mechanical calculator. This machine is considered to be the forerunner of the modern computer though none of them were built in his lifetime.

Molecular machines

Study of the molecules and proteins that are the basis of biological functions has led to the concept of a molecular machine. For example, current models of the operation of the kinesin molecule that transports vesicles inside the cell as well as the myocin molecule that operates against actin to cause muscle contraction; these molecules control movement in response to chemical stimuli.

Researchers in nano-technology are working to construct molecules that perform movement in response to a specific stimulus. In contrast to molecules such as kinesin and myosin, these nano-machines or molecular machines are constructions like traditional machines that are designed to perform in a task.

Machine elements

Machines are assembled from standardized types of components. These elements consist of mechanisms that control movement in various ways such as gear trains, transistor switches, belt or chain drives, linkages, cam and follower systems, brakes and clutches, and structural components such as frame members and fasteners.

Modern machines include sensors, actuators and computer controllers. The shape, texture and color of covers provide a styling and operational interface between the mechanical components of a machine and its users.

Mechanisms

Assemblies within a machine that control movement are often called "mechanisms." ^[8]^[9] Mechanisms are generally classified as gears and gear trains, cam and follower mechanisms, and linkages, though there are other special mechanisms such as clamping linkages, indexing mechanisms and friction devices such as brakes and clutches.

For more details on mechanical machines see Machine (mechanical) and Mechanical systems.

Controllers

Controllers combine sensors, logic, and actuators to maintain the performance of components of a machine. Perhaps the best known is the 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 the cruise control system in an automobile. The programmable logic controller replaced relays and specialized control mechanisms with a programmable computer. Servomotors that accurately position a shaft in response to an electrical command are the actuators that make robotic systems possible.

Design

Design plays an important role in all three of the major phases of a product 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.

Types and related components

Types of machines and related components
Classification		Machine(s)
Simple machines		Inclined plane, Wheel and axle, Lever, Pulley, Wedge, Screw
Mechanical components		Axle, Bearings, Belts, Bucket, Fastener, Gear, Key, Link chains, Rack and pinion, Roller chains, Rope, Seals, Spring, Wheel
Clock		Atomic clock, Chronometer, Pendulum clock, Quartz clock
Compressors and Pumps		Archimedes' screw, Eductor-jet pump, Hydraulic ram, Pump, Trompe, Vacuum pump
Heat engines	External combustion engines	Steam engine, Stirling engine
Heat engines	Internal combustion engines	Reciprocating engine, Gas turbine
Heat pumps		Absorption refrigerator, Thermoelectric refrigerator, Regenerative cooling
Linkages		Pantograph, Cam, Peaucellier-Lipkin
Turbine		Gas turbine, Jet engine, Steam turbine, Water turbine, Wind generator, Windmill
Aerofoil		Sail, Wing, Rudder, Flap, Propeller
Electronic devices		Vacuum tube, Transistor, Diode, Resistor, Capacitor, Inductor, Memristor, Semiconductor, Computer
Robots		Actuator, Servo, Servomechanism, Stepper motor, Computer
Miscellaneous		Vending machine, Wind tunnel, Check weighing machines, Riveting machines

References

^ ^a ^b The American Heritage Dictionary, Second College Edition. Houghton Mifflin Co., 1985.
^ "μηχανή", Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus project
^ "μῆχος", Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus project
^ Oxford English Dictionary
^ Merriam-Webster Dictionary Definition of machine
^ "Motor". Dictionary.reference.com. Retrieved 2011-05-09. a person or thing that imparts motion, esp. a contrivance, as a steam engine, that receives and modifies energy from some natural source in order to utilize it in driving machinery.
^ Dictionary.com: (World heritage) "3. any device that converts another form of energy into mechanical energy to produce motion"
^ Reuleaux, F., 1876 The Kinematics of Machinery, (trans. and annotated by A. B. W. Kennedy), reprinted by Dover, New York (1963)
^ J. J. Uicker, G. R. Pennock, and J. E. Shigley, 2003, Theory of Machines and Mechanisms, Oxford University Press, New York.

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 {{About|devices that perform tasks|other uses|Machine (disambiguation)}}
 {{See|Equipment (disambiguation)}}
-A '''machine''' manages power to accomplish a task.  Examples include, a [[Machine (mechanical)|mechanical system]], a [[computer|computing system]], an [[electronic system]], and a [[molecular machine]].  In common usage, the meaning is that of a device having parts that perform or assist in performing any type of [[Work (physics)|work]]. A [[simple machine]] is a device that transforms the direction or magnitude of a [[force]]. Example of a machine: Ryan Sean Taylor. otherwise known as Ry Ry
+A '''machine''' manages power to accomplish a task.  Examples include, a [[Machine (mechanical)|mechanical system]], a [[computer|computing system]], an [[electronic system]], and a [[molecular machine]].  In common usage, the meaning is that of a device having parts that perform or assist in performing any type of [[Work (physics)|work]]. A [[simple machine]] is a device that transforms the direction or magnitude of a [[force]].
 The word "machine" is derived from the [[Latin]] word ''machina'',<ref name=AHD>''The American Heritage Dictionary'', Second College Edition. Houghton Mifflin Co., 1985.</ref> which in turn derives from the [[Doric Greek]] ''μαχανά'' (machana), [[Ionic Greek]] ''μηχανή'' (mechane) "contrivance, machine, engine"<ref>[http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dmhxanh%2F "μηχανή"], Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus project</ref> and that from ''μῆχος'' (mechos), "means, expedient, remedy".<ref>[http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dmh%3Dxos "μῆχος"], Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus project</ref>