Devices designed for the production of theatrical effects, including rapid scene changes, lighting, sound effects, and illusions. Such devices have been in use since the 5th century BCE, when the Greeks developed a crane to lower to the stage an actor playing a god (see deus ex machina), as well as movable scenery mounted on wheels. Medieval mystery plays used trapdoors to allow the emergence of devils and used flying machines for angels. In the Italian Renaissance, elaborate machinery was used for spectacles produced in the churches on holy days. In the 17th century, the Italian Giacomo Torelli (1608–78) invented a system for moving the stage wings that made it possible to change scenery quickly. In the 19th century, magical illusions were created with mirror devices and refined trapdoors. By the late 20th century, spectacle had fallen out of fashion except in musical theatre, but hydraulic stage machinery allowed for swift and soundless scene changes. Seealso stagecraft.
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Machine from which various goods may be purchased, either with coin, paper currency, or electronic payment card. The first vending machines were introduced in 18th-century England to sell snuff and tobacco. From the late 19th century they have been widely used in many countries. Vending service is typically provided by a company that owns the machines and places them in businesses, schools, and the like. These operators provide the products and service either without cost to the owner of the premises on which a machine is located or in return for a servicing charge.
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Machine for stitching material (such as cloth or leather), usually having a needle and shuttle to carry thread and powered by treadle or electricity. Invented by Elias Howe in 1846 and successfully manufactured by Howe and Isaac Merritt Singer, it became the first widely distributed mechanical home appliance and has also been an important industrial machine. Modern sewing machines are usually powered by an electric motor, but the foot-treadle machine is still in wide use in much of the world.
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Machine tool for cutting up bars of material or for cutting out shapes in plates of raw material. The cutting tools (saws) may be thin metallic disks with teeth on their edges, thin metal blades or flexible bands with teeth on one edge, or thin grinding wheels. The tools may use any of three actions: true cutting, grinding, or friction-created melting.
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In U.S. politics, a political organization that controls enough votes to maintain political and administrative control of its community. The rapid growth of cities in the 19th century created huge problems for city governments, which were often poorly organized and unable to provide services. Enterprising politicians were able to win support by offering favours, including patronage jobs and housing, in exchange for votes. Though machines often helped to restructure city governments to the benefit of their constituents, they just as often resulted in poorer service (when jobs were doled out as political rewards), corruption (when contracts or concessions were awarded in return for kickbacks), and aggravation of racial or ethnic hostilities (when the machine did not reflect the city's diversity). Reforms, suburban flight, and a more mobile population with fewer ties to city neighbourhoods have weakened machine politics. Famous machines include those of William Magear Tweed (New York), James Michael Curley (Boston), Thomas Pendergast (Kansas City, Mo.), and Richard J. Daley (Chicago). Seealso civil service.
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Machine tool that rotates a circular tool with numerous cutting edges arranged symmetrically about its axis, called a milling cutter. The metal workpiece is usually held in a vise clamped to a table that can move in three perpendicular directions. Cutters of many shapes and sizes are available for a wide variety of milling operations. Milling machines cut flat surfaces, grooves, shoulders, inclined surfaces, dovetails, and T-slots. Various form-tooth cutters are used for cutting concave forms and convex grooves, for rounding corners, and for cutting gear teeth.
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Stationary, power-driven machine used to cut, shape, or form materials such as metal and wood. Machine tools date from the invention of the steam engine in the 18th century; most common machine tools were designed by the middle of the 19th century. Today dozens of different machine tools are used in the workshops of home and industry. They are frequently classified into seven types: turning machines such as lathes; shapers and planers; power drills or drill presses; milling machines; grinding machines; power saws; and presses (e.g., punch presses).
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Automatic weapon capable of rapid, sustained fire, usually 500–1,000 rounds per minute. Developed in the late 19th century by such inventors as Hiram Maxim, it profoundly altered modern warfare. The World War I battlefield was dominated by the belt-fed machine gun, which remained little changed into World War II. Modern machine guns are classified into three groups: the squad automatic weapon, chambered for small-calibre assault-rifle ammunition and operated by one soldier; the general-purpose machine gun, firing full-power rifle ammunition and operated by two; and the heavy machine gun, firing rounds of 12.7 mm (.5 in) or higher and often mounted on an armoured vehicle. Seealso submachine gun.
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Device that amplifies or replaces human or animal effort to accomplish a physical task. A machine may be further defined as a device consisting of two or more parts that transmit or modify force and motion in order to do work. The five simple machines are the lever, the wedge, the wheel and axle, the pulley, and the screw; all complex machines are combinations of these basic devices. The operation of a machine may involve the transformation of chemical, thermal, electrical, or nuclear energy into mechanical energy, or vice versa. All machines have an input, an output, and a transforming or modifying and transmitting device. Machines that receive their input energy from a natural source (such as air currents, moving water, coal, petroleum, or uranium) and transform it into mechanical energy are known as prime movers; examples include windmills, waterwheels, turbines, steam engines, and internal-combustion engines.
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Machine tool that uses a rotating abrasive grinding wheel to change the shape or dimensions of a hard, usually metallic, workpiece. Grinding is the most accurate of all the basic machining processes. All grinding machines use a wheel made from one of the manufactured abrasives, silicon carbide or aluminum oxide. To grind a cylindrical form, the workpiece rotates as it is fed against the grinding wheel. To grind an internal surface, a small wheel moves inside the hollow of the workpiece, which is gripped in a rotating chuck. On a surface grinder, the workpiece is held in place on a table that moves under the rotating abrasive wheel.
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Machine tool, usually hydraulically operated, for finishing surfaces by drawing or pushing a cutter called a broach entirely over and past the surface. A broach has a series of cutting teeth arranged in a row or rows, graduated in height from the teeth that cut first to those that cut last. Each tooth removes only a few thousandths of an inch, and the total depth of cut is distributed over all the teeth. Broaching is particularly suitable for internal surfaces such as holes and internal gears, but it can also shape external gears and flat surfaces.
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Machine tool for producing smooth and accurate holes in a workpiece by enlarging existing holes with a cutting tool, which may bear a single tip of steel, cemented carbide, or diamond or may be a small grinding wheel. The hole's diameter is controlled by adjusting the boring head. Bored holes are more accurate in roundness, concentricity, and parallelism than drilled holes. Boring machines used in toolmaking shops have a vertical spindle and a work-holding table that moves horizontally in two perpendicular directions so that holes can be accurately spaced. In mass-production plants, boring machines with multiple spindles are common. Seealso drill; drill press; lathe.
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Hypothetical computing device proposed by Alan M. Turing (1936). Not actually a machine, it is an idealized mathematical model that reduces the logical structure of any computing device to its essentials. It consists of an infinitely extensible tape, a tape head that is capable of performing various operations on the tape, and a modifiable control mechanism in the head that can store instructions. As envisaged by Turing, it performs its functions in a sequence of discrete steps. His extrapolation of the essential features of information processing was instrumental in the development of modern digital computers, which share his basic scheme of an input/output device (tape and tape reader), central processing unit (CPU, or control mechanism), and stored memory.
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Mechanical devices, including tractors and implements, used in farming to save labour. The great variety of farming devices covers a wide range of complexity, from simple hand-held implements used since prehistoric times to the complex harvesters of modern mechanized agriculture. From the early 19th century to the present, the chief source of power in farming has changed from animals to steam power, then to gasoline, and finally to diesel. In developed countries, the number of farmworkers has steadily declined in the 20th century, while farm production has increased because of the use of machinery.
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Machinery's Handbook for machine shop and drafting-room; a reference book on machine design and shop practice for the mechanical engineer, draftsman, toolmaker, and machinist (the full title of the 1st edition) is a classic reference work in mechanical engineering and practical workshop mechanics in one volume published by Industrial Press, Inc., New York, since 1914. The first edition was created by Erik Oberg (1881–1951) and Franklin D. Jones (1879–1967), who are still mentioned on the title page of the 28th edition (2008). Recent editions of the handbook contain chapters on mathematics, mechanics, materials, measuring, toolmaking, manufacturing, threading, gears, and machine elements, combined with excerpts from ANSI standards.
In 1917, Oberg and Jones also published Machinery's Encyclopedia in 7 volumes. The handbook and encyclopedia are named after the monthly magazine Machinery (Industrial Press, 1894–1973), where the two were consulting editors.
Today, the phrases "machinist's handbook" or "machinists' handbook" are almost always imprecise references to Machinery's Handbook. During the decades from World War I through World War II, these phrases could refer to either of two competing reference books: McGraw-Hill's American Machinists' Handbook or Industrial Press's Machinery's Handbook. The former book ceased publication after the 8th edition (1945). (One short-lived spin-off appeared in 1955.) The latter book, Machinery's Handbook, is still regularly revised and updated, and it continues to be a "bible of the metalworking industries" today.
Machinery's Handbook is apparently the direct inspiration for similar works in other countries, such as Sweden's Karlebo handbok (1st ed. 1936).