A pantograph (Greek roots παντ- "all, every" and γραφ- "to write", from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen. If a line drawing is traced by the first point, an identical, enlarged, or miniaturized copy will be drawn by a pen fixed to the other. Using the same principle, different kinds of pantographs are used for other forms of duplication in areas such as sculpture, minting, engraving and milling.
Because of the shape of the original device, a pantograph also refers to a kind of structure that can compress or extend like an accordion, forming a characteristic rhomboidal pattern. This can be found in extension arms for wall-mounted mirrors, temporary fences, scissor lifts, and other scissor mechanisms such as the pantograph used in electric locomotives and trams.
== History ==
The first pantograph was constructed in 1603〔"The Galileo Project — Scheiner, Christoph" (history), Al Van Helden, Galileo Project, 1995, (galileo.rice.edu )〕 by Christoph Scheiner, who used the device to copy and scale diagrams, but he wrote about the invention over 27 years later, in ''"Pantographice"'' (Rome 1631).〔The full title of ''"Pantographice"'' is ''"Pantographice seu Ars delineandi res quaslibet per parallelogrammum lineare seu cavum"'' (Rome 1631).〕
One arm of the pantograph contained a small pointer, while the other held a drawing implement, and by moving the pointer over a diagram, a copy of the diagram was drawn on another piece of paper. By changing the positions of the arms in the linkage between the pointer arm and drawing arm, the scale of the image produced can be changed. A more complicated version called the eidograph was developed by William Wallace (1768–1843) in 1831.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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