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A gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of the rotation of its support (e.g. vertical in the first animation). For example, on a ship, the gyroscopes, shipboard compasses, stoves, and even drink holders typically use gimbals to keep them upright with respect to the horizon despite the ship's pitching and rolling. The gimbal suspension used for mounting compasses and the like is sometimes called a Cardan suspension after Italian mathematician and physicist Gerolamo Cardano (1501–1576) described it in detail. However, Cardano did not invent the gimbal, nor did he claim to. The device has been known since antiquity and may not have a single identifiable inventor.〔Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering''. Taipei: Caves Books Ltd. Page 229.〕〔Francis C. Moon, ''The Machines of Leonardo da Vinci and Franz Reuleaux: Kinematics of Machines from the Renaissance to the 20th Century'', p.314, Springer, 2007 ISBN 1-4020-5598-6.〕 ==History== The gimbal was first described by the Greek inventor Philo of Byzantium (280–220 BC).〔 Philo described an eight-sided ink pot with an opening on each side, which can be turned so that while any face is on top, a pen can be dipped and inked — yet the ink never runs out through the holes of the other sides. This was done by the suspension of the inkwell at the center, which was mounted on a series of concentric metal rings so that it remained stationary no matter which way the pot is turned. The authenticity of Philo's description of a cardan suspension has been doubted by some authors on the ground that the part of Philo's ''Pneumatica'' which describes the use of the gimbal survived only in an Arabic translation of the early 9th century.〔 Thus, the sinologist Joseph Needham suspected Arab interpolation as late as 1965.〔Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering''. Taipei: Caves Books Ltd. p.236.〕 However, Carra de Vaux, author of the French translation which still provides the basis for modern scholars, regards the Pneumatics as essentially genuine.〔Carra de Vaux: "Le livre des appareils pneumatiques et des machines hydrauliques de Philon de Byzance d'après les versions d'Oxford et de Constantinople", Académie des Inscriptions et des Belles Artes: notice et extraits des mss. de la Bibliothèque nationale, Paris 38 (1903), pp.27-235〕 The historian of technology George Sarton (1959) also asserts that it is safe to assume the Arabic version is a faithful copying of Philo's original, and credits Philon explicitly with the invention.〔Sarton, George. (1959). A History of Science: Hellenistic Science and Culture in the Last Three Centuries B.C. New York: The Norton Library, Norton & Company Inc. SBN 393005267. pp.343–350.〕 So does his colleague Michael Lewis (2001). In fact, research by the latter scholar (1997) demonstrates that the Arab copy contains sequences of Greek letters which fell out of use after the 1st century, thereby strengthening the case that it is a faithful copy of the Hellenistic original, a view recently also shared by the classicist Andrew Wilson (2002). The ancient author Athenaeus Mechanicus, writing during the reign of Augustus (30 BC–14 AD), described the military use of a gimbal-like mechanism, calling it "little ape" (''pithêkion''): When preparing to attack coastal towns from the sea-side, military engineers used to yoke merchant-ships together to take the siege machines up to the walls. But to prevent the shipborne machinery from rolling around the deck in heavy seas, Athenaeus advises that "you must fix the ''pithêkion'' on the platform attached to the merchant-ships in the middle, so that the machine stays upright in any angle".〔Athenaeus Mechanicus, "On Machines" ("Peri Mēchanēmatōn"), 32.1-33.3〕 After antiquity, gimbals remained widely known in the Near East. In the Latin West, reference to the device appeared again in the 9th century recipe book called the ''Little Key of Painting'' Mappae clavicula.〔Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering''. Taipei: Caves Books Ltd. pp.229, 231.〕 The French inventor Villard de Honnecourt depicts a set of gimbals in his famous sketchbook (see right). In the early modern period, dry compasses were suspended in gimbals. In China, the Han Dynasty (202 BC – 220 AD) inventor Ding Huan created a gimbal incense burner around 180 CE.〔〔Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering''. Taipei: Caves Books Ltd. p.233.〕 There is a hint in the writing of the earlier Sima Xiangru (179–117 BC) that the gimbal existed in China since the 2nd century BC.〔Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering''. Taipei: Caves Books Ltd. pp.233–234.〕 There is mention during the Liang Dynasty (502–557) that gimbals were used for hinges of doors and windows, while an artisan once presented a portable warming stove to Empress Wu Zetian (r. 690–705) which employed gimbals.〔Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering''. Taipei: Caves Books Ltd. p.234.〕 Extant specimens of Chinese gimbals used for incense burners date to the early Tang Dynasty (618–907), and were part of the silver-smithing tradition in China.〔Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering''. Taipei: Caves Books Ltd. pp.234–235.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「gimbal」の詳細全文を読む スポンサード リンク
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