起重機的用途與歷史課程畢業(yè)設(shè)計外文文獻翻譯、外文翻譯、中英文翻譯

1、<p>　　The Use and History of Crane</p><p>　　Every time we see a crane in action we remains without words, these machines are sometimes really huge, taking up tons of material hundreds of meters in heigh

2、t. We watch with amazement and a bit of terror, thinking about what would happen if the load comes off or if the movement of the crane was wrong. It is a really fascinating system, surprising both adults and children. Th

3、ese are especially tower cranes, but in reality there are plenty of types and they are in use for centuries. The cranes ar</p><p>　　1. Overview</p><p>　　The first construction cranes were invent

4、ed by the Ancient Greeks and were powered by men or beasts of burden, such as donkeys. These cranes were used for the construction of tall buildings. Larger cranes were later developed, employing the use of human treadwh

5、eels, permitting the lifting of heavier weights. In the High Middle Ages, harbor cranes were introduced to load and unload ships and assist with their construction – some were built into stone towers for extra strength a

6、nd stability. The e</p><p>　　For many centuries, power was supplied by the physical exertion of men or animals, although hoists in watermills and windmills could be driven by the harnessed natural power. The

7、 first 'mechanical' power was provided by steam engines, the earliest steam crane being introduced in the 18th or 19th century, with many remaining in use well into the late 20th century. Modern cranes usually us

8、e internal combustion engines or electric motors and hydraulic systems to provide a much greater lifting capab</p><p>　　Cranes exist in an enormous variety of forms – each tailored to a specific use. Sizes r

9、ange from the smallest jib cranes, used inside workshops, to the tallest tower cranes, used for constructing high buildings. For a while, mini - cranes are also used for constructing high buildings, in order to facilitat

10、e constructions by reaching tight spaces. Finally, we can find larger floating cranes, generally used to build oil rigs and salvage sunken ships. This article also covers lifting machines that </p><p>　　2. H

11、istory</p><p>　　Ancient Greece</p><p>　　The crane for lifting heavy loads was invented by the Ancient Greeks in the late 6th century BC. The archaeological record shows that no later than c.515

12、BC distinctive cuttings for both lifting tongs and lewis irons begin to appear on stone blocks of Greek temples. Since these holes point at the use of a lifting device, and since they are to be found either above the cen

13、ter of gravity of the block, or in pairs equidistant from a point over the center of gravity, they are regarded by archaeologi</p><p>　　The introduction of the winch and pulley hoist soon lead to a widesprea

14、d replacement of ramps as the main means of vertical motion. For the next two hundred years, Greek building sites witnessed a sharp drop in the weights handled, as the new lifting technique made the use of several smalle

15、r stones more practical than of fewer larger ones. In contrast to the archaic period with its tendency to ever-increasing block sizes, Greek temples of the classical age like the Parthenon invariably featured </p>

16、<p>　　Although the exact circumstances of the shift from the ramp to the crane technology remain unclear, it has been argued that the volatile social and political conditions of Greece were more suitable to the emp

17、loyment of small, professional construction teams than of large bodies of unskilled labor, making the crane more preferable to the Greek polis than the more labor-intensive ramp which had been the norm in the autocratic

18、societies of Egypt or Assyria. </p><p>　　The first unequivocal literary evidence for the existence of the compound pulley system appears in the Mechanical Problems (Mech. 18, 853a32-853b13) attributed to Ari

19、stotle (384-322 BC), but perhaps composed at a slightly later date. Around the same time, block sizes at Greek temples began to match their archaic predecessors again, indicating that the more sophisticated compound pull

20、ey must have found its way to Greek construction sites by then. </p><p>　　Ancient Rome</p><p>　　The heyday of the crane in ancient times came during the Roman Empire, when construction activity

21、soared and buildings reached enormous dimensions. The Romans adopted the Greek crane and developed it further. We are relatively well informed about their lifting techniques, thanks to rather lengthy accounts by the engi

22、neers Vitruvius (De Architectura 10.2, 1-10) and Heron of Alexandria (Mechanica 3.2-5). There are also two surviving reliefs of Roman treadwheel cranes, with the Haterii tombstone fr</p><p>　　The simplest Ro

23、man crane, the Trispastos, consisted of a single-beam jib, a winch, a rope, and a block containing three pulleys. Having thus a mechanical advantage of 3:1, it has been calculated that a single man working the winch coul

24、d raise 150 kg (3 pulleys x 50 kg = 150), assuming that 50 kg represent the maximum effort a man can exert over a longer time period. Heavier crane types featured five pulleys (Pentaspastos) or, in case of the largest on

25、e, a set of three by five pulleys (Polyspasto</p><p>　　However, numerous extant Roman buildings which feature much heavier stone blocks than those handled by the Polyspastos indicate that the overall lifting

26、 capability of the Romans went far beyond that of any single crane. At the temple of Jupiter at Baalbek, for instance, the architrave blocks weigh up to 60 tons each, and one corner cornice block even over 100 tons, all

27、of them raised to a height of about 19 m. In Rome, the capital block of Trajan's Column weighs 53.3 tons, which had to be lifted</p><p>　　It is assumed that Roman engineers lifted these extraordinary wei

28、ghts by two measures (see picture below for comparable Renaissance technique): First, as suggested by Heron, a lifting tower was set up, whose four masts were arranged in the shape of a quadrangle with parallel sides, no

29、t unlike a siege tower, but with the column in the middle of the structure (Mechanica 3.5). Second, a multitude of capstans were placed on the ground around the tower, for, although having a lower leverage ratio tha</

30、p><p>　　Middle Ages</p><p>　　During the High Middle Ages, the treadwheel crane was reintroduced on a large scale after the technology had fallen into disuse in western Europe with the demise of the

31、 Western Roman Empire. The earliest reference to a treadwheel (magna rota) reappears in archival literature in France about 1225, followed by an illuminated depiction in a manuscript of probably also French origin dating

32、 to 1240. In navigation, the earliest uses of harbor cranes are documented for Utrecht in 1244, Antwerp in 1263,</p><p>　　Generally, vertical transport could be done more safely and inexpensively by cranes t

33、han by customary methods. Typical areas of application were harbors, mines, and, in particular, building sites where the treadwheel crane played a pivotal role in the construction of the lofty Gothic cathedrals. Neverthe

34、less, both archival and pictorial sources of the time suggest that newly introduced machines like treadwheels or wheelbarrows did not completely replace more labor-intensive methods like ladders,</p><p>　　Ap

35、art from treadwheels, medieval depictions also show cranes to be powered manually by windlasses with radiating spokes, cranks and by the 15th century also by windlasses shaped like a ship's wheel. To smooth out irreg

36、ularities of impulse and get over 'dead-spots' in the lifting process flywheels are known to be in use as early as 1123. </p><p>　　The exact process by which the treadwheel crane was reintroduced is

37、not recorded, although its return to construction sites has undoubtedly to be viewed in close connection with the simultaneous rise of Gothic architecture. The reappearance of the treadwheel crane may have resulted from

38、a technological development of the windlass from which the treadwheel structurally and mechanically evolved. Alternatively, the medieval treadwheel may represent a deliberate reinvention of its Roman counterpart </p&g

39、t;<p>　　Structure and placement</p><p>　　The medieval treadwheel was a large wooden wheel turning around a central shaft with a treadway wide enough for two workers walking side by side. While the ear

40、lier 'compass-arm' wheel had spokes directly driven into the central shaft, the more advanced 'clasp-arm' type featured arms arranged as chords to the wheel rim, giving the possibility of using a thinner

41、shaft and providing thus a greater mechanical advantage. </p><p>　　Contrary to a popularly held belief, cranes on medieval building sites were neither placed on the extremely lightweight scaffolding used at

42、the time nor on the thin walls of the Gothic churches which were incapable of supporting the weight of both hoisting machine and load. Rather, cranes were placed in the initial stages of construction on the ground, often

43、 within the building. When a new floor was completed, and massive tie beams of the roof connected the walls, the crane was dismantled and re</p><p>　　Less frequently, medieval illuminations also show cranes

44、mounted on the outside of walls with the stand of the machine secured to putlogs.</p><p>　　Mechanics and operation</p><p>　　In contrast to modern cranes, medieval cranes and hoists - much like t

45、heir counterparts in Greece and Rome - were primarily capable of a vertical lift, and not used to move loads for a considerable distance horizontally as well. Accordingly, lifting work was organized at the workplace in a

46、 different way than today. In building construction, for example, it is assumed that the crane lifted the stone blocks either from the bottom directly into place, or from a place opposite the centre of the wall</p>

47、<p>　　It is noteworthy that medieval cranes rarely featured ratchets or brakes to forestall the load from running backward. This curious absence is explained by the high friction force exercised by medieval treadw

48、heels which normally prevented the wheel from accelerating beyond control. </p><p>　　Harbor usage</p><p>　　According to the "present state of knowledge" unknown in antiquity, stationar

49、y harbor cranes are considered a new development of the Middle Ages. The typical harbor crane was a pivoting structure equipped with double treadwheels. These cranes were placed docksides for the loading and unloading of

50、 cargo where they replaced or complemented older lifting methods like see-saws, winches and yards. </p><p>　　Two different types of harbor cranes can be identified with a varying geographical distribution: W

51、hile gantry cranes which pivoted on a central vertical axle were commonly found at the Flemish and Dutch coastside, German sea and inland harbors typically featured tower cranes where the windlass and treadwheels were si

52、tuated in a solid tower with only jib arm and roof rotating. Interestingly, dockside cranes were not adopted in the Mediterranean region and the highly developed Italian ports where </p><p>　　Unlike construc

53、tion cranes where the work speed was determined by the relatively slow progress of the masons, harbor cranes usually featured double treadwheels to speed up loading. The two treadwheels whose diameter is estimated to be

54、4 m or larger were attached to each side of the axle and rotated together. Today, according to one survey, fifteen treadwheel harbor cranes from pre-industrial times are still extant throughout Europe.[28] Beside these s

55、tationary cranes, floating cranes which could</p><p>　　Renaissance</p><p>　　A lifting tower similar to that of the ancient Romans was used to great effect by the Renaissance architect Domenico F

56、ontana in 1586 to relocate the 361 t heavy Vatican obelisk in Rome. From his report, it becomes obvious that the coordination of the lift between the various pulling teams required a considerable amount of concentration

57、and discipline, since, if the force was not applied evenly, the excessive stress on the ropes would make them rupture. </p><p>　　Early modern age</p><p>　　Cranes were used domestically in the 17

58、th and 18th century. The chimney or fireplace crane was used to swing pots and kettles over the fire and the height was adjusted by a trammel. </p><p>　　3. Mechanical principles</p><p>　　There a

59、re two major considerations in the design of cranes. The first is that the crane must be able to lift a load of a specified weight and the second is that the crane must remain stable and not topple over when the load is

60、lifted and moved to another location.</p><p>　　Lifting capacity</p><p>　　Cranes illustrate the use of one or more simple machines to create mechanical advantage.</p><p>　　?The leve

61、r. A balance crane contains a horizontal beam (the lever) pivoted about a point called the fulcrum. The principle of the lever allows a heavy load attached to the shorter end of the beam to be lifted by a smaller force a

62、pplied in the opposite direction to the longer end of the beam. The ratio of the load's weight to the applied force is equal to the ratio of the lengths of the longer arm and the shorter arm, and is called the mechan

63、ical advantage. </p><p>　　?The pulley. A jib crane contains a tilted strut (the jib) that supports a fixed pulley block. Cables are wrapped multiple times round the fixed block and round another block attac

64、hed to the load. When the free end of the cable is pulled by hand or by a winding machine, the pulley system delivers a force to the load that is equal to the applied force multiplied by the number of lengths of cable pa

65、ssing between the two blocks. This number is the mechanical advantage. </p><p>　　?The hydraulic cylinder. This can be used directly to lift the load or indirectly to move the jib or beam that carries anothe

66、r lifting device. </p><p>　　Cranes, like all machines, obey the principle of conservation of energy. This means that the energy delivered to the load cannot exceed the energy put into the machine. For exampl

67、e, if a pulley system multiplies the applied force by ten, then the load moves only one tenth as far as the applied force. Since energy is proportional to force multiplied by distance, the output energy is kept roughly e

68、qual to the input energy (in practice slightly less, because some energy is lost to friction and othe</p><p><b>　　Stability</b></p><p>　　For stability, the sum of all moments about a

69、ny point such as the base of the crane must equate to zero. In practice, the magnitude of load that is permitted to be lifted (called the "rated load" in the US) is some value less than the load that will cause

70、 the crane to tip (providing a safety margin).</p><p>　　Under US standards for mobile cranes, the stability-limited rated load for a crawler crane is 75% of the tipping load. The stability-limited rated load

71、 for a mobile crane supported on outriggers is 85% of the tipping load. These requirements, along with additional safety-related aspects of crane design, are established by the American Society of Mechanical Engineers in

72、 the volume ASME B30.5-2007 Mobile and Locomotive Cranes.</p><p>　　Standards for cranes mounted on ships or offshore platforms are somewhat stricter because of the dynamic load on the crane due to vessel mot

73、ion. Additionally, the stability of the vessel or platform must be considered.</p><p>　　For stationary pedestal or kingpost mounted cranes, the moment created by the boom, jib, and load is resisted by the pe

74、destal base or kingpost. Stress within the base must be less than the yield stress of the material or the crane will fail.</p><p>　　4. Types of the cranes</p><p><b>　　Mobile</b></

75、p><p>　　Main article: Mobile crane</p><p>　　The most basic type of mobile crane consists of a truss or telescopic boom mounted on a mobile platform - be it on road, rail or water.</p><p&

76、gt;<b>　　Fixed</b></p><p>　　Exchanging mobility for the ability to carry greater loads and reach greater heights due to increased stability, these types of cranes are characterized that they, or a

77、t least their main structure does not move during the period of use. However, many can still be assembled and disassembled.</p><p>　　5. Overhead Cranes</p><p><b>　　Use</b></p>

78、<p>　　The most common overhead crane use is in the steel industry. Every step of steel, until it leaves a factory as a finished product, the steel is handled by an overhead crane. Raw materials are poured into a fu

79、rnace by crane, hot steel is stored for cooling by an overhead crane, the finished coils are lifted and loaded onto trucks and trains by overhead crane, and the fabricator or stamper uses an overhead crane to handle the

80、steel in his factory. The automobile industry uses overhead cranes for h</p><p><b>　　History</b></p><p>　　Alton Shaw, of the Shaw Crane Company, is credited with the first overhead c

81、rane, in 1874. Alliance Machine, now defunct, holds an AISE citation for one of the earliest cranes as well. This crane was in service until approximately 1980, and is now in a museum in Birmingham, Alabama. Over the yea

82、rs important innovations, such as the Weston load brake (which is now rare) and the wire rope hoist (which is still popular), have come and gone. The original hoist contained components mated together in </p><

83、p>　　Notable cranes and dates</p><p>　　?1874: Alton Shaw develops the first overhead crane. </p><p>　　?1938: Yale introduces the Cable-King hoist. </p><p>　　?1944: Shepard-Niles

84、supplies a hoist for lifting atomic bombs for testing in New Mexico. </p><p>　　?1969: Power Electronics International, Inc. developed the overhead hoist variable speed drive. </p><p>　　?1983:

85、The world's biggest overhead crane from Bardella Company starts its operation at Itaipu dam Hydro Power Plant Brazil. </p><p>　　?1997: Industry giant P&H files for chapter eleven bankruptcy. Later r

86、enamed Morris Material Handling but still using the P&H tradename, they again went bankrupt. </p><p>　　?1998: Dearborn Crane supplies two 500-ton capacity overhead cranes to Verson Press of Chicago. The

87、 cranes were never used due to Verson's bankruptcy. </p><p><b>　　起重機的用途與歷史</b></p><p>　　每當我們看到一臺正在運作的起重機，我們都會驚訝不已，這些機器有時碩大無比，能把成噸的貨物提升到半空中?？吹竭@些龐然大物的時候我們心理都帶著一種驚愕，有時甚至是有一點恐懼的心情，我們

88、會去想如果吊著著的東西掉下來了或者是起重機吊錯了位置會發(fā)生什么樣恐怖的事情。起重機的確是一種令人著迷的機械系統(tǒng)，無論是成人或者是孩子無不為止驚嘆。起重機的種類五花八門，并且歷史悠久。起重機是用一個或者幾個簡單的機器來組成一個機械結(jié)構(gòu)并用于運送那些人無法搬動的物品。一般來說，起重機由一個卷筒、一束金屬繩或者是一條金屬鏈組成用來同時提升、放置或者是水平移動貨物。起重機的工作領(lǐng)域一般是在需要裝卸貨物的運輸業(yè)、需要搬運建材的建筑業(yè)和需要組裝重型

89、設(shè)備的制造業(yè)。</p><p><b>　　1. 概況</b></p><p>　　第一臺具有機械結(jié)構(gòu)的起重機是由古希臘人發(fā)明的，并且由人或者是牲畜比如驢，作為動力源。這種起重機被用于大型建筑的建造。這種起重機后來發(fā)展成了采用人力踏板驅(qū)動的更大型的起重機，用于提升更重的物料。中世紀時港口起重機被用來裝卸船上的貨物，有的港口起重機為求更大的起重重量和更好的穩(wěn)定性被造在了

90、石塔里。最早的起重機是用木頭制造的，但是工業(yè)革命之后，鑄鐵和鋼材就代替了木頭用于制造起重機。</p><p>　　盡管水磨機和風車都可以利用自然的能源來驅(qū)動，但是幾個世紀以來，起重機的動力源一直是人力或者是畜力。第一臺真正采用機械能量的起重機用的是蒸汽機，最早的蒸汽起重機出現(xiàn)于18到19世紀，有一些甚至到了20世紀末仍能很好地使用。雖然由于能源的供應(yīng)仍不可及，到現(xiàn)在有一些人力起重機還在使用，但是現(xiàn)代的起重機一般采

91、用的內(nèi)燃機、電動馬達、液壓系統(tǒng)能為起重機提供比之前大得多的提升力。</p><p>　　起重機的類型多種多樣－每一種都是量身定做。尺寸由最小的在車間里使用的臂式起重機到用于建造高樓的最高的塔式起重機應(yīng)有盡有。然而，小型的起重機也被用來建造摩天大樓，目的是為了在高樓中狹小的空間內(nèi)使用使建造更加方便。最后，我們來看看更加巨型的浮船式起重機，一般用來建造石油鉆探平臺和打撈沉沒的船只。這篇文章也會涉及到之前沒有提到，但是

92、也非常常見的的起重機械，比如說堆垛起重機和裝卸起重機。</p><p><b>　　2. 歷史</b></p><p><b>　　古希臘時期</b></p><p>　　用來提升重型貨物的其中節(jié)是古希臘人在公元前六世紀晚期發(fā)明的?？脊庞涗涳@示最早在公元前515年提升夾具和鐵制的吊楔開始出現(xiàn)在古希臘人石塊結(jié)構(gòu)的神殿里。由于

93、這些是起重設(shè)備的核心裝置、也由于他們是在石塊的重心的中央或者是在離重心上一點距離相等的兩頭被發(fā)現(xiàn)，他們被考古學家認為是起重機當時就存在的確鑿證據(jù)。</p><p>　　絞盤與滑輪的的引入導致了人類之前用斜坡來向高處運送貨物的方法被廣泛替代。在接下來的兩百年中，希臘的建筑都采用了這樣新型的提升物料的技術(shù)，它利用了一些小型的石塊來來代替大塊的石頭，這樣更具實用性。與更早先的古希臘人神殿的建筑材料的尺寸不斷變得越來越大

94、趨勢相比較，希臘古典廟宇比如帕臺農(nóng)神廟的石塊重量都小于15－20噸。而且，要把巨型的石柱豎立起來的作業(yè)古希臘人實際上更喜歡用好幾塊像鼓一樣的圓柱石塊堆疊而成。</p><p>　　盡管確切是何時從斜坡運輸進入起重機提升技術(shù)時代的時間還不是很清楚。但是當時古希臘不穩(wěn)定的社會局勢、和政治情況使得建造神殿更適合雇傭小型的、更加專業(yè)的建筑團隊而不是像埃及和亞述那樣大量使用的沒有技術(shù)的勞動力。這樣的情況使得起重機更像是希臘

95、城邦發(fā)明的而非是采用純勞動力斜坡運送貨物的埃及或是亞述那樣的獨裁國家。 </p><p>　　文學上第一次的明確的記載滑輪組的復合系統(tǒng)是出現(xiàn)在亞里士多德的機械難題中，但是組成文字可能還要稍晚一些。與此同時，用于建造希臘神廟的石塊尺寸再一次開始趕上他們的古代前輩了，這標志著當時更多的久經(jīng)考驗的的滑輪組一定在希臘建筑史上找到了它們的一席之地。</p><p><b>　　古羅馬時期&

96、lt;/b></p><p>　　起重機械在古代的全盛時期卻是在古羅馬帝國展開的。當時建筑物的數(shù)量激增，而且這些建筑都達到了巨型的尺寸。羅馬人采用了希臘人的起重機并將其發(fā)揚光大。多虧了那些維特魯威工程師們撰寫的相當冗長的文獻和亞歷山大大帝的蒼鷺的巢，我們才得以如此詳細地了解到了它們的其中技術(shù)。目前與Haterii的墓碑一起現(xiàn)存于世還有兩座公元一世紀晚期、雕刻精細的古羅馬腳踏式起重機的浮雕作品。</p&

97、gt;<p>　　三餅滑車是古羅馬最簡單的一種起重機，它是由一個單梁吊臂、一個絞盤、一條繩子和一個三個滑輪組成的滑輪組組成的。這樣就有能夠省下3倍的力。經(jīng)計算，假設(shè)一個人用盡力氣能夠長時間地提起相當于重50千克的物體那么通過這樣的起重機械他可以提升約150千克的物體（3個滑輪X50千克＝150千克）。更加重型的起重機就擁有五個滑輪（五餅滑車），最大型的起重機會在兩根、三根甚至是四根桅桿上面裝上三餅和五餅的復合滑輪組（復滑車

98、），這是由最大的負載載荷決定的。復滑車工作的時候兩邊需要4個人：兩邊各站兩個已經(jīng)可以提起重約3000千克的物體（3條繩子X5個滑輪X4個人X50千克＝3000千克）。如果用踏車來代替絞盤的話，最大的起重載荷可以在人工減半的情況下達到兩倍－6000千克，因為踏車有更大的直徑能夠提供一個大得多的力矩。這意味著，和建造埃及金字塔時50個人才能通過斜坡搬動2.5噸的石塊（50千克每人）的情況相比，羅馬的復滑車的提升能力把工作的效率提高60倍（3

99、000千克每人）。</p><p>　　然而，大量現(xiàn)存的古羅馬建筑中那些石塊的重量比復滑車所能操作的負載要重得多。這表明古羅馬人全面的起重的能力要遠遠任何簡單的起重機。以Baalbek的Jupiter神廟為例，那些楣梁的石塊每塊都重達60噸以上，每個檐口的石塊甚至達到了100噸以上，所有這些石料都被提升到了19m的半空中。在羅馬Trajan之柱的主要石塊重達53.3噸，而這些石塊必須被提升到34m的高度。（見Tr