Badi'al-Zaman Abū al-'Izz ibn Ismā'īl ibn al-Razāz al-Jazarī (1136–1206) was a Kurdish[1][2][3][4] Muslim polymath: a scholar, inventor, mechanical engineer, craftsman, artist, and mathematician from Jazirat ibn Umar (current Cizre), who lived during the Islamic Golden Age (Middle Ages). He is best known for writing the al-Jāmiʿ bain al-ʿilm wa al-ʿamal al-nāfiʿ fī ṣināʿat al-ḥiyal (The Book of Knowledge of Ingenious Mechanical Devices) in 1206, where he described 100 mechanical devices, some 80 of which are trick vessels of various kinds, along with instructions on how to construct themBiography
Little is known about al-Jazari, and most of that comes from the introduction to his Book of Knowledge of Ingenious Mechanical Devices. He was named after the area in which he was born (the city of Jazirat ibn Umar). Like his father before him, he served as chief engineer at the Artuklu Palace, the residence of the Mardin branch of the Turkish Artuqid dynasty which ruled across eastern Anatolia as vassals of the Zangid rulers of Mosul and later Ayyubid general Saladin.[7] He was born in the city of Tor,[8] now located in the district of Cizre in south-Eastern Turkey.
al-Jazari was part of a tradition of craftsmen and was thus more of a practical engineer than an inventor[9] who appears to have been "more interested in the craftsmanship necessary to construct the devices than in the technology which lay behind them" and his machines were usually "assembled by trial and error rather than by theoretical calculation."[10] His Book of Knowledge of Ingenious Mechanical Devices appears to have been quite popular as it appears in a large number of manuscript copies, and as he explains repeatedly, he only describes devices he has built himself. According to Mayr, the book's style resembles that of a modern "do-it-yourself" book.[11]
Some of his devices were inspired by earlier devices, such as one of his monumental water clocks, which was based on that of a Pseudo-Archimedes.[12] He also cites the influence of the Banu Musa brothers for his fountains, al-Asturlabi for the design of a candle clock, and Hibat Allah ibn al-Husayn (d. 1139) for musical automata. Al-Jazari goes on to describe the improvements he made to the work of his predecessors, and describes a number of devices, techniques and components that are original innovations which do not appear in the works by his precessors.[13]
Mechanisms and methods
While many of al-Jazari's inventions may now appear to be trivial, the most significant aspect of al-Jazari's machines are the mechanisms, components, ideas, methods, and design features which they employ.[7]
Camshaft
The camshaft, a shaft to which cams are attached, was first introduced in 1206 by al-Jazari, who employed them in his automata,[14] water clocks (such as the candle clock)[15] and water-raising machines.[14] The cam and camshaft later appeared in European mechanisms from the 14th century.[16]
Crankshaft and crank-slider mechanism
The eccentrically mounted handle of the rotary handmill in 5th century BC Spain that spread across the Roman Empire constitutes a crank.[17] The earliest evidence of a crank and connecting rod mechanism dates to the 3rd century AD Hierapolis sawmill in the Roman Empire.[17] The crank also appears in the mid-9th century in several of the hydraulic devices described by the Banū Mūsā brothers in their Book of Ingenious Devices.[18]In 1206, al-Jazari invented an early crankshaft,[19][20] which he incorporated with a crank-connecting rod mechanism in his twin-cylinder pump.[21]
Like the modern crankshaft, Al-Jazari's mechanism consisted of a wheel setting several crank pins into motion, with the wheel's motion being circular and the pins moving back-and-forth in a straight line.[19] The crankshaft described by al-Jazari[19][20] transforms continuous rotary motion into a linear reciprocating motion,[21] and is central to modern machinery such as the steam engine, internal combustion engine and automatic controls.[20][22]He used the crankshaft with a connecting rod in two of his water-raising machines: the crank-driven saqiya chain pump and the double-action reciprocating piston suction pump.[21][23] His water pump also employed the first known crank-slider mechanism.[24]
Design and construction methods
English technology historian Donald Routledge Hill writes:
We see for the first time in al-Jazari's work several concepts important for both design and construction: the lamination of timber to minimize warping, the static balancing of wheels, the use of wooden templates (a kind of pattern), the use of paper models to establish designs, the calibration of orifices, the grinding of the seats and plugs of valves together with emery powder to obtain a watertight fit, and the casting of metals in closed mold boxes with sand.[7]
Escapement mechanism in a rotating wheel
Al-Jazari invented a method for controlling the speed of rotation of a wheel using an escapement mechanism.[25]
Mechanical controls
According to Donald Routledge Hill, al-Jazari described several early mechanical controls, including "a large metal door, a combination lock and a lock with four bolts."[7]
Segmental gear
A segmental gear is "a piece for receiving or communicating reciprocating motion from or to a cogwheel, consisting of a sector of a circular gear, or ring, having cogs on the periphery, or face."[26] Professor Lynn Townsend White, Jr. wrote:
Segmental gears first clearly appear in al-Jazari, in the West they emerge in Giovanni de Dondi's astronomical clock finished in 1364, and only with the great Sienese engineer Francesco di Giorgio (1501) did they enter the general vocabulary of European machine design.[27]
Water-raising machines
Al-Jazari invented five machines for raising water,[28] as well as watermills and water wheels with cams on their axle used to operate automata,[29] in the 12th and 13th centuries, and described them in 1206. It was in these water-raising machines that he introduced his most important ideas and components.
Saqiya chain pumps
The first known use of a crankshaft in a chain pump was in one of al-Jazari's saqiya machines. The concept of minimizing intermittent working is also first implied in one of al-Jazari's saqiya chain pumps, which was for the purpose of maximising the efficiency of the saqiya chain pump. Al-Jazari also constructed a water-raising saqiya chain pump which was run by hydropower rather than manual labour, though the Chinese were also using hydropower for chain pumps prior to him. Saqiya machines like the ones he described have been supplying water in Damascus since the 13th century up until modern times,[30] and were in everyday use throughout the medieval Islamic world.[31]
Double-action suction pump with valves and reciprocating piston motion
Citing the Byzantine siphon used for discharging Greek fire as an inspiration,[32] al-Jazari went on to describe the first suction pipes, suction pump, double-action pump, and made early uses of valves and a crankshaft-connecting rod mechanism, when he invented a twin-cylinder reciprocating piston suction pump. This pump is driven by a water wheel, which drives, through a system of gears, an oscillating slot-rod to which the rods of two pistons are attached. The pistons work in horizontally opposed cylinders, each provided with valve-operated suction and delivery pipes. The delivery pipes are joined above the centre of the machine to form a single outlet into the irrigation system. This water-raising machine had a direct significance for the development of modern engineering. This pump is remarkable for three reasons:[7][33][34]
- The first known use of a true suction pipe (which sucks fluids into a partial vacuum) in a pump.
- The first application of the double-acting principle.
- The conversion of rotary to reciprocating motion, via the crank-connecting rod mechanism.
al-Jazari's suction piston pump could lift 13.6 metres of water,[citation needed] with the help of delivery pipes. This was more advanced than the suction pumps that appeared in 15th-century Europe, which lacked delivery pipes. It was not, however, any more efficient than a noria commonly used by the Muslim world at the time.[34]
Water supply system
al-Jazari developed the earliest water supply system to be driven by gears and hydropower, which was built in 13th century Damascus to supply water to its mosques and Bimaristan hospitals. The system had water from a lake turn a scoop-wheel and a system of gears which transported jars of water up to a water channel that led to mosques and hospitals in the city.[35]
Automata
al-Jazari built automated moving peacocks driven by hydropower.[36] He also invented the earliest known automatic gates, which were driven by hydropower.[35] He also created automatic doors as part of one of his elaborate water clocks,[7] He also invented water wheels with cams on their axle used to operate automata.[29] According to Encyclopædia Britannica, the Italian Renaissance inventor Leonardo da Vinci may have been influenced by the classic automata of al-Jazari.[37]
Mark E. Rosheim summarizes the advances in robotics made by Arab engineers, especially al-Jazari, as follows:
Unlike the Greek designs, these Arab examples reveal an interest, not only in dramatic illusion, but in manipulating the environment for human comfort. Thus, the greatest contribution the Arabs made, besides preserving, disseminating and building on the work of the Greeks, was the concept of practical application. This was the key element that was missing in Greek robotic science.[38]
The Arabs, on the other hand, displayed an interest in creating human-like machines for practical purposes but lacked, like other preindustrial societies, any real impetus to pursue their robotic science.[39]
Drink-serving waitress
One of al-Jazari's humanoid automata was a waitress that could serve water, tea or drinks. The drink was stored in a tank with a reservoir from where the drink drips into a bucket and, after seven minutes, into a cup, after which the waitress appears out of an automatic door serving the drink.[40]
Hand-washing automaton with flush mechanism
al-Jazari invented a hand washing automaton incorporating a flush mechanism now used in modern flush toilets. It features a female humanoid automaton standing by a basin filled with water. When the user pulls the lever, the water drains and the female automaton refills the basin.[41]
Peacock fountain with automated servants
al-Jazari's "peacock fountain" was a more sophisticated hand washing device featuring humanoid automata as servants which offer soap and towels. Mark E. Rosheim describes it as follows:[38]
Pulling a plug on the peacock's tail releases water out of the beak; as the dirty water from the basin fills the hollow base a float rises and actuates a linkage which makes a servant figure appear from behind a door under the peacock and offer soap. When more water is used, a second float at a higher level trips and causes the appearance of a second servant figure – with a towel!.[5][6]
0 Comments