Crank (mechanism)
It was thought that evidence of the earliest true crank handle was found in a Han era glazed-earthenware tomb model of an agricultural winnowing fan dated no later than 200 AD,[3][4] but since then a series of similar pottery models with crank operated winnowing fans were unearthed, with one of them dating back to the Western Han dynasty (202 BC – 9 AD).
[7] Eventually crank-and-connecting rods were used in the inter-conversion or rotary and reciprocating motion for other applications such as flour-sifting, treadle spinning wheels, water-powered furnace bellows, and silk-reeling machines.
[34] In ancient literature, there is a reference to the workings of water-powered marble saws close to Trier, now Germany, by the late 4th century poet Ausonius;[30] about the same time, these mill types seem also to be indicated by the Greek Christian saint Gregory of Nyssa from Anatolia, demonstrating a diversified use of water-power in many parts of the Roman Empire[35] The three finds push back the date of the invention of the crank and connecting rod by a full millennium:[30] With the crank and connecting rod system, all elements for constructing a steam engine (invented in 1712) — Hero's aeolipile (generating steam power), the cylinder and piston (in metal force pumps), non-return valves (in water pumps), gearing (in water mills and clocks) — were known in Roman times.
[36] A rotary grindstone − the earliest representation of one −[37] which is operated by a crank handle is shown in the Carolingian manuscript Utrecht Psalter; the pen drawing of around 830 goes back to a late antique original.
[38] A musical tract ascribed to the abbot Odo of Cluny (c. 878−942) describes a fretted stringed instrument which was sounded by a resined wheel turned with a crank; the device later appears in two 12th century illuminated manuscripts.
[37] The use of crank handles in trepanation drills was depicted in the 1887 edition of the Dictionnaire des Antiquités Grecques et Romaines and ascribed to the Spanish Muslim surgeon Abu al-Qasim al-Zahrawi; however, the existence of such a device cannot be confirmed by the original illuminations and thus has to be discounted.
[39] The Italian physician Guido da Vigevano (c. 1280−1349), planning for a new crusade, made illustrations for a paddle boat and war carriages that were propelled by manually turned compound cranks and gear wheels (center of image).
[41] Kyeser also equipped the Archimedes screws for water-raising with a crank handle, an innovation which subsequently replaced the ancient practice of working the pipe by treading.
One of the drawings of the Anonymous of the Hussite Wars shows a boat with a pair of paddle-wheels at each end turned by men operating compound cranks (see above).
The concept was much improved by the Italian engineer and writer Roberto Valturio in 1463, who devised a boat with five sets, where the parallel cranks are all joined to a single power source by one connecting-rod, an idea also taken up by his compatriot Francesco di Giorgio.
[46] In Renaissance Italy, the earliest evidence of a compound crank and connecting-rod is found in the sketch books of Taccola, but the device is still mechanically misunderstood.
[47] The 15th century also saw the introduction of cranked rack-and-pinion devices, called cranequins, which were fitted to the crossbow's stock as a means of exerting even more force while spanning the missile weapon (see right).
Because of the findings at Ephesus and Gerasa the invention of the crank and connecting rod system has had to be redated from the 13th to the 6th c; now the Hierapolis relief takes it back another three centuries, which confirms that water-powered stone saw mills were indeed in use when Ausonius wrote his Mosella.Because of the findings at Ephesus and Gerasa the invention of the crank and connecting rod system has had to be redated from the 13th to the 6th c; now the Hierapolis relief takes it back another three centuries, which confirms that water-powered stone saw mills were indeed in use when Ausonius wrote his Mosella.
