32-5t吊钩桥式起重机设计（全套含CAD图纸）
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上传时间：2018-02-28
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桥式起重机
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1THEUSEANDHISTORYOFCRANEEVERYTIMEWESEEACRANEINACTIONWEREMAINSWITHOUTWORDS,THESEMACHINESARESOMETIMESREALLYHUGE,TAKINGUPTONSOFMATERIALHUNDREDSOFMETERSINHEIGHTWEWATCHWITHAMAZEMENTANDABITOFTERROR,THINKINGABOUTWHATWOULDHAPPENIFTHELOADCOMESOFFORIFTHEMOVEMENTOFTHECRANEWASWRONGITISAREALLYFASCINATINGSYSTEM,SURPRISINGBOTHADULTSANDCHILDRENTHESEAREESPECIALLYTOWERCRANES,BUTINREALITYTHEREAREPLENTYOFTYPESANDTHEYAREINUSEFORCENTURIESTHECRANESAREFORMEDBYONEORMOREMACHINESUSEDTOCREATEAMECHANICALADVANTAGEANDTHUSMOVELARGELOADSCRANESAREEQUIPPEDWITHAWINDER,AWIREROPEORCHAINANDSHEAVESTHATCANBEUSEDBOTHTOLIFTANDLOWERMATERIALSANDTOMOVETHEMHORIZONTALLYITUSESONEORMORESIMPLEMACHINESTOCREATEMECHANICALADVANTAGEANDTHUSMOVELOADSBEYONDTHENORMALCAPABILITYOFAHUMANCRANESARECOMMONLYEMPLOYEDINTHETRANSPORTINDUSTRYFORTHELOADINGANDUNLOADINGOFFREIGHT,INTHECONSTRUCTIONINDUSTRYFORTHEMOVEMENTOFMATERIALSANDINTHEMANUFACTURINGINDUSTRYFORTHEASSEMBLINGOFHEAVYEQUIPMENT1OVERVIEWTHEFIRSTCONSTRUCTIONCRANESWEREINVENTEDBYTHEANCIENTGREEKSANDWEREPOWEREDBYMENORBEASTSOFBURDEN,SUCHASDONKEYSTHESECRANESWEREUSEDFORTHECONSTRUCTIONOFTALLBUILDINGSLARGERCRANESWERELATERDEVELOPED,EMPLOYINGTHEUSEOFHUMANTREADWHEELS,PERMITTINGTHELIFTINGOFHEAVIERWEIGHTSINTHEHIGHMIDDLEAGES,HARBORCRANESWEREINTRODUCEDTOLOADANDUNLOADSHIPSANDASSISTWITHTHEIRCONSTRUCTIONSOMEWEREBUILTINTOSTONETOWERSFOREXTRASTRENGTHANDSTABILITYTHEEARLIESTCRANESWERECONSTRUCTEDFROMWOOD,BUTCASTIRONANDSTEELTOOKOVERWITHTHECOMINGOFTHEINDUSTRIALREVOLUTIONFORMANYCENTURIES,POWERWASSUPPLIEDBYTHEPHYSICALEXERTIONOFMENORANIMALS,ALTHOUGHHOISTSINWATERMILLSANDWINDMILLSCOULDBEDRIVENBY2THEHARNESSEDNATURALPOWERTHEFIRSTMECHANICALPOWERWASPROVIDEDBYSTEAMENGINES,THEEARLIESTSTEAMCRANEBEINGINTRODUCEDINTHE18THOR19THCENTURY,WITHMANYREMAININGINUSEWELLINTOTHELATE20THCENTURYMODERNCRANESUSUALLYUSEINTERNALCOMBUSTIONENGINESORELECTRICMOTORSANDHYDRAULICSYSTEMSTOPROVIDEAMUCHGREATERLIFTINGCAPABILITYTHANWASPREVIOUSLYPOSSIBLE,ALTHOUGHMANUALCRANESARESTILLUTILIZEDWHERETHEPROVISIONOFPOWERWOULDBEUNECONOMICCRANESEXISTINANENORMOUSVARIETYOFFORMSEACHTAILOREDTOASPECIFICUSESIZESRANGEFROMTHESMALLESTJIBCRANES,USEDINSIDEWORKSHOPS,TOTHETALLESTTOWERCRANES,USEDFORCONSTRUCTINGHIGHBUILDINGSFORAWHILE,MINICRANESAREALSOUSEDFORCONSTRUCTINGHIGHBUILDINGS,INORDERTOFACILITATECONSTRUCTIONSBYREACHINGTIGHTSPACESFINALLY,WECANFINDLARGERFLOATINGCRANES,GENERALLYUSEDTOBUILDOILRIGSANDSALVAGESUNKENSHIPSTHISARTICLEALSOCOVERSLIFTINGMACHINESTHATDONOTSTRICTLYFITTHEABOVEDEFINITIONOFACRANE,BUTAREGENERALLYKNOWNASCRANES,SUCHASSTACKERCRANESANDLOADERCRANES2HISTORYANCIENTGREECETHECRANEFORLIFTINGHEAVYLOADSWASINVENTEDBYTHEANCIENTGREEKSINTHELATE6THCENTURYBCTHEARCHAEOLOGICALRECORDSHOWSTHATNOLATERTHANC515BCDISTINCTIVECUTTINGSFORBOTHLIFTINGTONGSANDLEWISIRONSBEGINTOAPPEARONSTONEBLOCKSOFGREEKTEMPLESSINCETHESEHOLESPOINTATTHEUSEOFALIFTINGDEVICE,ANDSINCETHEYARETOBEFOUNDEITHERABOVETHECENTEROFGRAVITYOFTHEBLOCK,ORINPAIRSEQUIDISTANTFROMAPOINTOVERTHECENTEROFGRAVITY,THEYAREREGARDEDBYARCHAEOLOGISTSASTHEPOSITIVEEVIDENCEREQUIREDFORTHEEXISTENCEOFTHECRANETHEINTRODUCTIONOFTHEWINCHANDPULLEYHOISTSOONLEADTOAWIDESPREADREPLACEMENTOFRAMPSASTHEMAINMEANSOFVERTICALMOTIONFORTHENEXTTWOHUNDREDYEARS,GREEKBUILDINGSITESWITNESSEDASHARPDROPINTHEWEIGHTS3HANDLED,ASTHENEWLIFTINGTECHNIQUEMADETHEUSEOFSEVERALSMALLERSTONESMOREPRACTICALTHANOFFEWERLARGERONESINCONTRASTTOTHEARCHAICPERIODWITHITSTENDENCYTOEVERINCREASINGBLOCKSIZES,GREEKTEMPLESOFTHECLASSICALAGELIKETHEPARTHENONINVARIABLYFEATUREDSTONEBLOCKSWEIGHINGLESSTHAN1520TONSALSO,THEPRACTICEOFERECTINGLARGEMONOLITHICCOLUMNSWASPRACTICALLYABANDONEDINFAVOROFUSINGSEVERALCOLUMNDRUMSALTHOUGHTHEEXACTCIRCUMSTANCESOFTHESHIFTFROMTHERAMPTOTHECRANETECHNOLOGYREMAINUNCLEAR,ITHASBEENARGUEDTHATTHEVOLATILESOCIALANDPOLITICALCONDITIONSOFGREECEWEREMORESUITABLETOTHEEMPLOYMENTOFSMALL,PROFESSIONALCONSTRUCTIONTEAMSTHANOFLARGEBODIESOFUNSKILLEDLABOR,MAKINGTHECRANEMOREPREFERABLETOTHEGREEKPOLISTHANTHEMORELABORINTENSIVERAMPWHICHHADBEENTHENORMINTHEAUTOCRATICSOCIETIESOFEGYPTORASSYRIATHEFIRSTUNEQUIVOCALLITERARYEVIDENCEFORTHEEXISTENCEOFTHECOMPOUNDPULLEYSYSTEMAPPEARSINTHEMECHANICALPROBLEMSMECH18,853A32853B13ATTRIBUTEDTOARISTOTLE384322BC,BUTPERHAPSCOMPOSEDATASLIGHTLYLATERDATEAROUNDTHESAMETIME,BLOCKSIZESATGREEKTEMPLESBEGANTOMATCHTHEIRARCHAICPREDECESSORSAGAIN,INDICATINGTHATTHEMORESOPHISTICATEDCOMPOUNDPULLEYMUSTHAVEFOUNDITSWAYTOGREEKCONSTRUCTIONSITESBYTHENANCIENTROMETHEHEYDAYOFTHECRANEINANCIENTTIMESCAMEDURINGTHEROMANEMPIRE,WHENCONSTRUCTIONACTIVITYSOAREDANDBUILDINGSREACHEDENORMOUSDIMENSIONSTHEROMANSADOPTEDTHEGREEKCRANEANDDEVELOPEDITFURTHERWEARERELATIVELYWELLINFORMEDABOUTTHEIRLIFTINGTECHNIQUES,THANKSTORATHERLENGTHYACCOUNTSBYTHEENGINEERSVITRUVIUSDEARCHITECTURA102,110ANDHERONOFALEXANDRIAMECHANICA325THEREAREALSOTWOSURVIVINGRELIEFSOFROMANTREADWHEELCRANES,WITHTHEHATERIITOMBSTONEFROMTHELATEFIRSTCENTURYADBEINGPARTICULARLYDETAILED4THESIMPLESTROMANCRANE,THETRISPASTOS,CONSISTEDOFASINGLEBEAMJIB,AWINCH,AROPE,ANDABLOCKCONTAININGTHREEPULLEYSHAVINGTHUSAMECHANICALADVANTAGEOF31,ITHASBEENCALCULATEDTHATASINGLEMANWORKINGTHEWINCHCOULDRAISE150KG3PULLEYSX50KG150,ASSUMINGTHAT50KGREPRESENTTHEMAXIMUMEFFORTAMANCANEXERTOVERALONGERTIMEPERIODHEAVIERCRANETYPESFEATUREDFIVEPULLEYSPENTASPASTOSOR,INCASEOFTHELARGESTONE,ASETOFTHREEBYFIVEPULLEYSPOLYSPASTOSANDCAMEWITHTWO,THREEORFOURMASTS,DEPENDINGONTHEMAXIMUMLOADTHEPOLYSPASTOS,WHENWORKEDBYFOURMENATBOTHSIDESOFTHEWINCH,COULDALREADYLIFT3000KG3ROPESX5PULLEYSX4MENX50KG3000KGINCASETHEWINCHWASREPLACEDBYATREADWHEEL,THEMAXIMUMLOADEVENDOUBLEDTO6000KGATONLYHALFTHECREW,SINCETHETREADWHEELPOSSESSESAMUCHBIGGERMECHANICALADVANTAGEDUETOITSLARGERDIAMETERTHISMEANTTHAT,INCOMPARISONTOTHECONSTRUCTIONOFTHEEGYPTIANPYRAMIDS,WHEREABOUT50MENWERENEEDEDTOMOVEA25TONSTONEBLOCKUPTHERAMP50KGPERPERSON,THELIFTINGCAPABILITYOFTHEROMANPOLYSPASTOSPROVEDTOBE60TIMESHIGHER3000KGPERPERSONHOWEVER,NUMEROUSEXTANTROMANBUILDINGSWHICHFEATUREMUCHHEAVIERSTONEBLOCKSTHANTHOSEHANDLEDBYTHEPOLYSPASTOSINDICATETHATTHEOVERALLLIFTINGCAPABILITYOFTHEROMANSWENTFARBEYONDTHATOFANYSINGLECRANEATTHETEMPLEOFJUPITERATBAALBEK,FORINSTANCE,THEARCHITRAVEBLOCKSWEIGHUPTO60TONSEACH,ANDONECORNERCORNICEBLOCKEVENOVER100TONS,ALLOFTHEMRAISEDTOAHEIGHTOFABOUT19MINROME,THECAPITALBLOCKOFTRAJANSCOLUMNWEIGHS533TONS,WHICHHADTOBELIFTEDTOAHEIGHTOFABOUT34MSEECONSTRUCTIONOFTRAJANSCOLUMNITISASSUMEDTHATROMANENGINEERSLIFTEDTHESEEXTRAORDINARYWEIGHTSBYTWOMEASURESSEEPICTUREBELOWFORCOMPARABLERENAISSANCETECHNIQUEFIRST,ASSUGGESTEDBYHERON,ALIFTINGTOWERWASSETUP,WHOSEFOURMASTSWEREARRANGEDINTHESHAPEOFAQUADRANGLEWITHPARALLELSIDES,NOTUNLIKEASIEGETOWER,BUTWITHTHECOLUMNINTHEMIDDLEOFTHESTRUCTUREMECHANICA535SECOND,AMULTITUDEOFCAPSTANSWEREPLACEDONTHEGROUNDAROUNDTHETOWER,FOR,ALTHOUGHHAVINGALOWERLEVERAGERATIOTHANTREADWHEELS,CAPSTANSCOULDBESETUPINHIGHERNUMBERSANDRUNBYMOREMENAND,MOREOVER,BYDRAUGHTANIMALSTHISUSEOFMULTIPLECAPSTANSISALSODESCRIBEDBYAMMIANUSMARCELLINUS17415INCONNECTIONWITHTHELIFTINGOFTHELATERANENSEOBELISKINTHECIRCUSMAXIMUSCA357ADTHEMAXIMUMLIFTINGCAPABILITYOFASINGLECAPSTANCANBEESTABLISHEDBYTHENUMBEROFLEWISIRONHOLESBOREDINTOTHEMONOLITHINCASEOFTHEBAALBEKARCHITRAVEBLOCKS,WHICHWEIGHBETWEEN55AND60TONS,EIGHTEXTANTHOLESSUGGESTANALLOWANCEOF75TONPERLEWISIRON,THATISPERCAPSTANLIFTINGSUCHHEAVYWEIGHTSINACONCERTEDACTIONREQUIREDAGREATAMOUNTOFCOORDINATIONBETWEENTHEWORKGROUPSAPPLYINGTHEFORCETOTHECAPSTANSMIDDLEAGESDURINGTHEHIGHMIDDLEAGES,THETREADWHEELCRANEWASREINTRODUCEDONALARGESCALEAFTERTHETECHNOLOGYHADFALLENINTODISUSEINWESTERNEUROPEWITHTHEDEMISEOFTHEWESTERNROMANEMPIRETHEEARLIESTREFERENCETOATREADWHEELMAGNAROTAREAPPEARSINARCHIVALLITERATUREINFRANCEABOUT1225,FOLLOWEDBYANILLUMINATEDDEPICTIONINAMANUSCRIPTOFPROBABLYALSOFRENCHORIGINDATINGTO1240INNAVIGATION,THEEARLIESTUSESOFHARBORCRANESAREDOCUMENTEDFORUTRECHTIN1244,ANTWERPIN1263,BRUGGEIN1288ANDHAMBURGIN1291,WHILEINENGLANDTHETREADWHEELISNOTRECORDEDBEFORE1331GENERALLY,VERTICALTRANSPORTCOULDBEDONEMORESAFELYANDINEXPENSIVELYBYCRANESTHANBYCUSTOMARYMETHODSTYPICALAREASOFAPPLICATIONWEREHARBORS,MINES,AND,INPARTICULAR,BUILDINGSITESWHERETHETREADWHEELCRANEPLAYEDAPIVOTALROLEINTHECONSTRUCTIONOFTHELOFTYGOTHICCATHEDRALSNEVERTHELESS,BOTHARCHIVALANDPICTORIALSOURCESOFTHETIMESUGGESTTHATNEWLYINTRODUCEDMACHINESLIKETREADWHEELSORWHEELBARROWSDIDNOTCOMPLETELYREPLACEMORELABORINTENSIVEMETHODSLIKELADDERS,HODSAND6HANDBARROWSRATHER,OLDANDNEWMACHINERYCONTINUEDTOCOEXISTONMEDIEVALCONSTRUCTIONSITESANDHARBORSAPARTFROMTREADWHEELS,MEDIEVALDEPICTIONSALSOSHOWCRANESTOBEPOWEREDMANUALLYBYWINDLASSESWITHRADIATINGSPOKES,CRANKSANDBYTHE15THCENTURYALSOBYWINDLASSESSHAPEDLIKEASHIPSWHEELTOSMOOTHOUTIRREGULARITIESOFIMPULSEANDGETOVERDEADSPOTSINTHELIFTINGPROCESSFLYWHEELSAREKNOWNTOBEINUSEASEARLYAS1123THEEXACTPROCESSBYWHICHTHETREADWHEELCRANEWASREINTRODUCEDISNOTRECORDED,ALTHOUGHITSRETURNTOCONSTRUCTIONSITESHASUNDOUBTEDLYTOBEVIEWEDINCLOSECONNECTIONWITHTHESIMULTANEOUSRISEOFGOTHICARCHITECTURETHEREAPPEARANCEOFTHETREADWHEELCRANEMAYHAVERESULTEDFROMATECHNOLOGICALDEVELOPMENTOFTHEWINDLASSFROMWHICHTHETREADWHEELSTRUCTURALLYANDMECHANICALLYEVOLVEDALTERNATIVELY,THEMEDIEVALTREADWHEELMAYREPRESENTADELIBERATEREINVENTIONOFITSROMANCOUNTERPARTDRAWNFROMVITRUVIUSDEARCHITECTURAWHICHWASAVAILABLEINMANYMONASTICLIBRARIESITSREINTRODUCTIONMAYHAVEBEENINSPIRED,ASWELL,BYTHEOBSERVATIONOFTHELABORSAVINGQUALITIESOFTHEWATERWHEELWITHWHICHEARLYTREADWHEELSSHAREDMANYSTRUCTURALSIMILARITIESSTRUCTUREANDPLACEMENTTHEMEDIEVALTREADWHEELWASALARGEWOODENWHEELTURNINGAROUNDACENTRALSHAFTWITHATREADWAYWIDEENOUGHFORTWOWORKERSWALKINGSIDEBYSIDEWHILETHEEARLIERCOMPASSARMWHEELHADSPOKESDIRECTLYDRIVENINTOTHECENTRALSHAFT,THEMOREADVANCEDCLASPARMTYPEFEATUREDARMSARRANGEDASCHORDSTOTHEWHEELRIM,GIVINGTHEPOSSIBILITYOFUSINGATHINNERSHAFTANDPROVIDINGTHUSAGREATERMECHANICALADVANTAGECONTRARYTOAPOPULARLYHELDBELIEF,CRANESONMEDIEVALBUILDINGSITESWERENEITHERPLACEDONTHEEXTREMELYLIGHTWEIGHTSCAFFOLDINGUSEDATTHETIMENORONTHETHINWALLSOFTHEGOTHICCHURCHESWHICHWEREINCAPABLEOFSUPPORTINGTHEWEIGHTOFBOTHHOISTINGMACHINEANDLOADRATHER,CRANESWERE7PLACEDINTHEINITIALSTAGESOFCONSTRUCTIONONTHEGROUND,OFTENWITHINTHEBUILDINGWHENANEWFLOORWASCOMPLETED,ANDMASSIVETIEBEAMSOFTHEROOFCONNECTEDTHEWALLS,THECRANEWASDISMANTLEDANDREASSEMBLEDONTHEROOFBEAMSFROMWHEREITWASMOVEDFROMBAYTOBAYDURINGCONSTRUCTIONOFTHEVAULTSTHUS,THECRANEGREWANDWANDEREDWITHTHEBUILDINGWITHTHERESULTTHATTODAYALLEXTANTCONSTRUCTIONCRANESINENGLANDAREFOUNDINCHURCHTOWERSABOVETHEVAULTINGANDBELOWTHEROOF,WHERETHEYREMAINEDAFTERBUILDINGCONSTRUCTIONFORBRINGINGMATERIALFORREPAIRSALOFTLESSFREQUENTLY,MEDIEVALILLUMINATIONSALSOSHOWCRANESMOUNTEDONTHEOUTSIDEOFWALLSWITHTHESTANDOFTHEMACHINESECUREDTOPUTLOGSMECHANICSANDOPERATIONINCONTRASTTOMODERNCRANES,MEDIEVALCRANESANDHOISTSMUCHLIKETHEIRCOUNTERPARTSINGREECEANDROMEWEREPRIMARILYCAPABLEOFAVERTICALLIFT,ANDNOTUSEDTOMOVELOADSFORACONSIDERABLEDISTANCEHORIZONTALLYASWELLACCORDINGLY,LIFTINGWORKWASORGANIZEDATTHEWORKPLACEINADIFFERENTWAYTHANTODAYINBUILDINGCONSTRUCTION,FOREXAMPLE,ITISASSUMEDTHATTHECRANELIFTEDTHESTONEBLOCKSEITHERFROMTHEBOTTOMDIRECTLYINTOPLACE,ORFROMAPLACEOPPOSITETHECENTREOFTHEWALLFROMWHEREITCOULDDELIVERTHEBLOCKSFORTWOTEAMSWORKINGATEACHENDOFTHEWALLADDITIONALLY,THECRANEMASTERWHOUSUALLYGAVEORDERSATTHETREADWHEELWORKERSFROMOUTSIDETHECRANEWASABLETOMANIPULATETHEMOVEMENTLATERALLYBYASMALLROPEATTACHEDTOTHELOADSLEWINGCRANESWHICHALLOWEDAROTATIONOFTHELOADANDWERETHUSPARTICULARLYSUITEDFORDOCKSIDEWORKAPPEAREDASEARLYAS1340WHILEASHLARBLOCKSWEREDIRECTLYLIFTEDBYSLING,LEWISORDEVILSCLAMPGERMANTEUFELSKRALLE,OTHEROBJECTSWEREPLACEDBEFOREINCONTAINERSLIKEPALLETS,BASKETS,WOODENBOXESORBARRELSITISNOTEWORTHYTHATMEDIEVALCRANESRARELYFEATUREDRATCHETSORBRAKESTOFORESTALLTHELOADFROMRUNNINGBACKWARDTHISCURIOUSABSENCEISEXPLAINEDBYTHEHIGHFRICTIONFORCEEXERCISEDBYMEDIEVALTREADWHEELSWHICHNORMALLY8PREVENTEDTHEWHEELFROMACCELERATINGBEYONDCONTROLHARBORUSAGEACCORDINGTOTHE“PRESENTSTATEOFKNOWLEDGE“UNKNOWNINANTIQUITY,STATIONARYHARBORCRANESARECONSIDEREDANEWDEVELOPMENTOFTHEMIDDLEAGESTHETYPICALHARBORCRANEWASAPIVOTINGSTRUCTUREEQUIPPEDWITHDOUBLETREADWHEELSTHESECRANESWEREPLACEDDOCKSIDESFORTHELOADINGANDUNLOADINGOFCARGOWHERETHEYREPLACEDORCOMPLEMENTEDOLDERLIFTINGMETHODSLIKESEESAWS,WINCHESANDYARDSTWODIFFERENTTYPESOFHARBORCRANESCANBEIDENTIFIEDWITHAVARYINGGEOGRAPHICALDISTRIBUTIONWHILEGANTRYCRANESWHICHPIVOTEDONACENTRALVERTICALAXLEWERECOMMONLYFOUNDATTHEFLEMISHANDDUTCHCOASTSIDE,GERMANSEAANDINLANDHARBORSTYPICALLYFEATUREDTOWERCRANESWHERETHEWINDLASSANDTREADWHEELSWERESITUATEDINASOLIDTOWERWITHONLYJIBARMANDROOFROTATINGINTERESTINGLY,DOCKSIDECRANESWERENOTADOPTEDINTHEMEDITERRANEANREGIONANDTHEHIGHLYDEVELOPEDITALIANPORTSWHEREAUTHORITIESCONTINUEDTORELYONTHEMORELABORINTENSIVEMETHODOFUNLOADINGGOODSBYRAMPSBEYONDTHEMIDDLEAGESUNLIKECONSTRUCTIONCRANESWHERETHEWORKSPEEDWASDETERMINEDBYTHERELATIVELYSLOWPROGRESSOFTHEMASONS,HARBORCRANESUSUALLYFEATUREDDOUBLETREADWHEELSTOSPEEDUPLOADINGTHETWOTREADWHEELSWHOSEDIAMETERISESTIMATEDTOBE4MORLARGERWEREATTACHEDTOEACHSIDEOFTHEAXLEANDROTATEDTOGETHERTODAY,ACCORDINGTOONESURVEY,FIFTEENTREADWHEELHARBORCRANESFROMPREINDUSTRIALTIMESARESTILLEXTANTTHROUGHOUTEUROPE28BESIDETHESESTATIONARYCRANES,FLOATINGCRANESWHICHCOULDBEFLEXIBLYDEPLOYEDINTHEWHOLEPORTBASINCAMEINTOUSEBYTHE14THCENTURYRENAISSANCEALIFTINGTOWERSIMILARTOTHATOFTHEANCIENTROMANSWASUSEDTOGREATEFFECTBYTHERENAISSANCEARCHITECTDOMENICOFONTANAIN1586TORELOCATETHE361THEAVYVATICANOBELISKINROMEFROMHISREPORT,ITBECOMESOBVIOUS9THATTHECOORDINATIONOFTHELIFTBETWEENTHEVARIOUSPULLINGTEAMSREQUIREDACONSIDERABLEAMOUNTOFCONCENTRATIONANDDISCIPLINE,SINCE,IFTHEFORCEWASNOTAPPLIEDEVENLY,THEEXCESSIVESTRESSONTHEROPESWOULDMAKETHEMRUPTUREEARLYMODERNAGECRANESWEREUSEDDOMESTICALLYINTHE17THAND18THCENTURYTHECHIMNEYORFIREPLACECRANEWASUSEDTOSWINGPOTSANDKETTLESOVERTHEFIREANDTHEHEIGHTWASADJUSTEDBYATRAMMEL3MECHANICALPRINCIPLESTHEREARETWOMAJORCONSIDERATIONSINTHEDESIGNOFCRANESTHEFIRSTISTHATTHECRANEMUSTBEABLETOLIFTALOADOFASPECIFIEDWEIGHTANDTHESECONDISTHATTHECRANEMUSTREMAINSTABLEANDNOTTOPPLEOVERWHENTHELOADISLIFTEDANDMOVEDTOANOTHERLOCATIONLIFTINGCAPACITYCRANESILLUSTRATETHEUSEOFONEORMORESIMPLEMACHINESTOCREATEMECHANICALADVANTAGETHELEVERABALANCECRANECONTAINSAHORIZONTALBEAMTHELEVERPIVOTEDABOUTAPOINTCALLEDTHEFULCRUMTHEPRINCIPLEOFTHELEVERALLOWSAHEAVYLOADATTACHEDTOTHESHORTERENDOFTHEBEAMTOBELIFTEDBYASMALLERFORCEAPPLIEDINTHEOPPOSITEDIRECTIONTOTHELONGERENDOFTHEBEAMTHERATIOOFTHELOADSWEIGHTTOTHEAPPLIEDFORCEISEQUALTOTHERATIOOFTHELENGTHSOFTHELONGERARMANDTHESHORTERARM,ANDISCALLEDTHEMECHANICALADVANTAGETHEPULLEYAJIBCRANECONTAINSATILTEDSTRUTTHEJIBTHATSUPPORTSAFIXEDPULLEYBLOCKCABLESAREWRAPPEDMULTIPLETIMESROUNDTHEFIXEDBLOCKANDROUNDANOTHERBLOCKATTACHEDTOTHELOADWHENTHEFREEENDOFTHECABLEISPULLEDBYHANDORBYAWINDINGMACHINE,THEPULLEYSYSTEMDELIVERSAFORCETOTHELOADTHATISEQUALTOTHEAPPLIEDFORCEMULTIPLIEDBYTHENUMBEROFLENGTHSOFCABLEPASSINGBETWEENTHETWOBLOCKSTHIS10NUMBERISTHEMECHANICALADVANTAGETHEHYDRAULICCYLINDERTHISCANBEUSEDDIRECTLYTOLIFTTHELOADORINDIRECTLYTOMOVETHEJIBORBEAMTHATCARRIESANOTHERLIFTINGDEVICECRANES,LIKEALLMACHINES,OBEYTHEPRINCIPLEOFCONSERVATIONOFENERGYTHISMEANSTHATTHEENERGYDELIVEREDTOTHELOADCANNOTEXCEEDTHEENERGYPUTINTOTHEMACHINEFOREXAMPLE,IFAPULLEYSYSTEMMULTIPLIESTHEAPPLIEDFORCEBYTEN,THENTHELOADMOVESONLYONETENTHASFARASTHEAPPLIEDFORCESINCEENERGYISPROPORTIONALTOFORCEMULTIPLIEDBYDISTANCE,THEOUTPUTENERGYISKEPTROUGHLYEQUALTOTHEINPUTENERGYINPRACTICESLIGHTLYLESS,BECAUSESOMEENERGYISLOSTTOFRICTIONANDOTHERINEFFICIENCIESSTABILITYFORSTABILITY,THESUMOFALLMOMENTSABOUTANYPOINTSUCHASTHEBASEOFTHECRANEMUSTEQUATETOZEROINPRACTICE,THEMAGNITUDEOFLOADTHATISPERMITTEDTOBELIFTEDCALLEDTHE“RATEDLOAD“INTHEUSISSOMEVALUELESSTHANTHELOADTHATWILLCAUSETHECRANETOTIPPROVIDINGASAFETYMARGINUNDERUSSTANDARDSFORMOBILECRANES,THESTABILITYLIMITEDRATEDLOADFORACRAWLERCRANEIS75OFTHETIPPINGLOADTHESTABILITYLIMITEDRATEDLOADFORAMOBILECRANESUPPORTEDONOUTRIGGERSIS85OFTHETIPPINGLOADTHESEREQUIREMENTS,ALONGWITHADDITIONALSAFETYRELATEDASPECTSOFCRANEDESIGN,AREESTABLISHEDBYTHEAMERICANSOCIETYOFMECHANICALENGINEERSINTHEVOLUMEASMEB3052007MOBILEANDLOCOMOTIVECRANESSTANDARDSFORCRANESMOUNTEDONSHIPSOROFFSHOREPLATFORMSARESOMEWHATSTRICTERBECAUSEOFTHEDYNAMICLOADONTHECRANEDUETOVESSELMOTIONADDITIONALLY,THESTABILITYOFTHEVESSELORPLATFORMMUSTBECONSIDEREDFORSTATIONARYPEDESTALORKINGPOSTMOUNTEDCRANES,THEMOMENTCREATEDBYTHEBOOM,JIB,ANDLOADISRESISTEDBYTHEPEDESTALBASEORKINGPOSTSTRESSWITHINTHEBASEMUSTBELESSTHANTHEYIELDSTRESSOFTHEMATERIALORTHECRANEWILLFAIL114TYPESOFTHECRANESMOBILEMAINARTICLEMOBILECRANETHEMOSTBASICTYPEOFMOBILECRANECONSISTSOFATRUSSORTELESCOPICBOOMMOUNTEDONAMOBILEPLATFORMBEITONROAD,RAILORWATERFIXEDEXCHANGINGMOBILITYFORTHEABILITYTOCARRYGREATERLOADSANDREACHGREATERHEIGHTSDUETOINCREASEDSTABILITY,THESETYPESOFCRANESARECHARACTERIZEDTHATTHEY,ORATLEASTTHEIRMAINSTRUCTUREDOESNOTMOVEDURINGTHEPERIODOFUSEHOWEVER,MANYCANSTILLBEASSEMBLEDANDDISASSEMBLED5OVERHEADCRANESUSETHEMOSTCOMMONOVERHEADCRANEUSEISINTHESTEELINDUSTRYEVERYSTEPOFSTEEL,UNTILITLEAVESAFACTORYASAFINISHEDPRODUCT,THESTEELISHANDLEDBYANOVERHEADCRANERAWMATERIALSAREPOUREDINTOAFURNACEBYCRANE,HOTSTEELISSTOREDFORCOOLINGBYANOVERHEADCRANE,THEFINISHEDCOILSARELIFTEDANDLOADEDONTOTRUCKSANDTRAINSBYOVERHEADCRANE,ANDTHEFABRICATORORSTAMPERUSESANOVERHEADCRANETOHANDLETHESTEELINHISFACTORYTHEAUTOMOBILEINDUSTRYUSESOVERHEADCRANESFORHANDLINGOFRAWMATERIALSSMALLERWORKSTATIONCRANESHANDLELIGHTERLOADSINAWORKAREA,SUCHASCNCMILLORSAWHISTORYALTONSHAW,OFTHESHAWCRANECOMPANY,ISCREDITEDWITHTHEFIRSTOVERHEADCRANE,IN1874ALLIANCEMACHINE,NOWDEFUNCT,HOLDSANAISECITATIONFORONEOFTHEEARLIESTCRANESASWELLTHISCRANEWASINSERVICEUNTILAPPROXIMATELY1980,ANDISNOWINAMUSEUMINBIRMINGHAM,ALABAMAOVERTHEYEARSIMPORTANTINNOVATIONS,SUCHASTHEWESTONLOADBRAKEWHICHISNOWRAREANDTHEWIREROPEHOISTWHICHISSTILLPOPULAR,HAVECOMEANDGONETHEORIGINALHOISTCONTAINEDCOMPONENTSMATEDTOGETHERINWHATISNOW12CALLEDTHEBUILTUPSTYLEHOISTTHESEBUILTUPHOISTSAREUSEDFORHEAVYDUTYAPPLICATIONSSUCHASSTEELCOILHANDLINGANDFORUSERSDESIRINGLONGLIFEANDBETTERDURABILITYTHEYALSOPROVIDEFOREASIERMAINTENANCENOWMANYHOISTSAREPACKAGEHOISTS,BUILTASONEUNITINASINGLEHOUSING,GENERALLYDESIGNEDFORTENYEARLIFEORLESSNOTABLECRANESANDDATES1874ALTONSHAWDEVELOPSTHEFIRSTOVERHEADCRANE1938YALEINTRODUCESTHECABLEKINGHOIST1944SHEPARDNILESSUPPLIESAHOISTFORLIFTINGATOMICBOMBSFORTESTINGINNEWMEXICO1969POWERELECTRONICSINTERNATIONAL,INCDEVELOPEDTHEOVERHEADHOISTVARIABLESPEEDDRIVE1983THEWORLDSBIGGESTOVERHEADCRANEFROMBARDELLACOMPANYSTARTSITSOPERATIONATITAIPUDAMHYDROPOWE
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