《機(jī)械工程專業(yè)英語(yǔ)》課件-機(jī)械工程專業(yè)英語(yǔ)課件-PART5

PART5EngineeringMachinesUnit21TheTwoLuffingCableCranesUnit22KomatsuD375ABulldozerUnit23KawasakiPowerLoaderUnit24KomatsuTruckUnit25CAD/CAM/CAPPUnit21TheTwoLuffingCableCranesNewwordsandexpressionsUnit21TheTwoLuffingCableCranesThetwoluffingcablecranesaredestinedfortheconstructionoftheThreeGorgesDaminthevalleyoftheYangtzeRiver.ThejobsiteissituatednearSandouping,YichangintheprovinceHubeiinthePeople’sRepublicofChina.Thecablecranes,representingthemaintransportfacilityofadamconstructionjobsite,havebeendesignedforthepurposeoftransportingconcrete,formworkitems,concretepre-fabitems,reinforcingmaterial,buildingmachineryandmachinecomponentssuchaspenstocks,generators,lockgates,etc.Thecablecranesthatwillbeusedonthejobsiteareoftheluffingtype,i.e.ithasbeengiventhatnamebecauseformovingthetrackrope,thetowersormastshavetolufftotheupstreamordownstreamdirection.Boththeslewingmastsofeachsinglecranebetweenwhichthetrackropesareinstalled,aresituatedatanelevationof+185monblock8alreadyconcretedontheleftbankandonthelongitudinalcofferdamattheelevationof+160m[1].Eachmasthasaheightof125+25=150m,andisfirmlyanchoredbyrearstayropesinlongitudinaldirection.Ontheirsides,themastsareheldrespectivelymovedby6-strandluffingropesactuatedbywinches.Thespansare:Rearstayropesontheleftbankapprox.270mRearstayropesontherightbankapprox.604.5mTrackropes:approx.1416mThemachinehousesforthewinchesofthecranesarearrangedonthefootofthemasts.Inthemachinehousesonthefootoftheheadtowersarearrangedthewinchesforhoistingcrabtraversingandmastluffing.Inthemachinehousesonthefootofthetailtowersareonlysituatedthewinchesformastluffing.Thismachinehousesarethereforecalledluffingwinchhouse.Thecontrolelectronicsareeachlocatedinseparaterooms,forthusavoidinganyproblemsasmightoccurbydustoralsotemperaturevariations.Therearethreepossibilitiestocontrolthewinches.Normallythecraneiscontrolledbythedriver’scabinthatismovablebetweenthemachinesideandthecountersideonalongcable.Thesecondwayistocontrolthecablecranebyawirelessportablecontrolunit.Foreachcranethereisonemobileunit.Thethirdpossibilitytocontrolthewinchesisthelocalcontroldevicenearbythemachinesforthehoist,crabtraversingandluffingsystems.Thelocalcontroldeviceisforpurposeofeasyadjustmentandrepairing.Becauseofthelocalsituation,therearecertainareasoftheworkingfieldwithobstacles.Theseareasarelockedbytheprogrammablecomputercontrolsystem.ForthecontrolsystemsalsoseetheElectricaldocumentsofABBCompany.ThecrabtraversingwinchisdrivenbyaDC-motorthatallowsforaninfinitelyvariablespeedregulation.Forphysicsreasonstheaccelerationshouldn’tbemuchbeyond0.75m/s2.Thereofresultaccelerationandbrakingtimesofapprox.10seconds(brakingtorqueabout6000Nm)[4].;respectivepathisapprox.37.5m.Withcommissioningoperationsthemechanicalbrakeshallbesetinawaythattheloadedcrabwillcometobestoppedafteratthelatest12seconds(brakingtorqueapprox.6000Nm).Hereonehastocheckperiodicallyforensuringauniformrunninginthetwogrooves(seeSection“Maintenance”).Betweenthetwogroovesthecrabtraversingropeisledoverthereturnpulley,attheshaftofwhichisalsofittedthescrew-typelimitswitchandthepositionindicator,justalsothetachometersformeasuringthespeedandforcontrolofapossibleoverspeed.Althoughthescrew-typelimitswitchandthepositionindicatoraredrivenbythenon-drivenreturnpulley,itisunavoidablethatafteradurationofoperationoccursacertainmiss-indication,sothatthecorrectionwillhavetobemade(seeSection“TraversingLimitSwitchesandPositionIndicators”)..Forsafetyreasonshavebeeninstalled,however,atthefirstandatthelastropecarrieradditionallimitswitchesformonitoringthecrabspeed.Sincetheselimitswitchescannotshiftoutoftheirsetposition,thesignalisabsolute.Finallythecrabtraversingisthenstoppedbyaleverlimitswitchattachedateachendofthetrackrope.Thetachometerformonitoringapossiblyoccurringoverspeeddisconnectsthecrabtraversinggearat115%ratedspeedby“emergencyoff”.Forprovidingtheoperationandmaintenanceteamwithinformationconcerningtheplantoutput,thecrabtraversinggearisequippedwithanoperationhour’scounterandacyclecounter.Heretheoperationhourscounterisdetectingthetimeinwhichthecrabtraversingmotorisworking,andthecyclecounterthenumberoftraversingruns.Therefore,thecyclecounterissetinawaythataftereachmotoroperationtimeofabout10secondsinonedirectionanotherhalfcycleiscountedup[5].Incasethetravelisinterruptedandcontinued,thereafterinthesamedirectionnonewhalfcyclewillbeadded.Incasethedirectionoftravelisreversed,however,andthenwillresultafteranother10secondsanewhalfcycle.Thecyclecountershallbeahelpforthemaintenanceteamtogetabetterideaabouttheworkinglifeofvariouswearingitemssuchastrolleytraversingrope,hoistingrope,ropecarriers,drivepulleylining,etc..Itisnecessarythatwiththeexchangeoftheseitemsarealwaysreadatthecyclecountertheresp.workingcyclesandthattheresultswillberegistered.Asanadditionalmaintenancehelpalubricantstankismountedtothetraversingwinchforlubricationofthecrabtraversingrope.TraversingLimitSwitchesandPositionIndicatorsAsmentionedintheprevioussection,thepositionindicatorandthetraversinglimitswitch(ascrew-typelimitswitch)arearrangedontheshaftofthereturnpulley,fromwhichtheycanbothbeseparatedbyamagnetictoothcoupling.Witherectionthetraversinglimitswitchissetinawaythatthecrabstopstravel130mbeforereachingthemachineside[7],orresp110mbeforethecounterside.Thepositionindicatorshouldthenshowthecorrespondingvalue.Duringoperation,thecrabisautomaticallybrakeddownelectricallytov=0m/s,whenoneofthetwoendpositionsisreached.Ontheremainingtrackropelengthtravelisthenonlypossible,whentheby-passbuttonisdepressed.Bydepressingtheby-passbuttonthetravelspeedisalsolimitedtov<20％ofvrated.Runninginoppositedirectionwithinthisrange,thereisnospeedlimitation.Inordertoensureprincipallyareductionofthecrabspeed,theplanthasbeenequippedwithtwoadditionalstationarymonitoringlimitswitches.Thesearearrangedonalwaysthefirstandthelastropecarrier.Astheseareinparallelconnectionwiththescrew-typelimitswitch,theyalsocauseareductionofthecrabtraversingspeedtov=0m/sbyelectricalbreaking.Tocontinuethetraveltotheendofthetrackropeisonlypossiblebydepressingtheby-passbutton.Thecrabtraversingisfinallystoppedelectricallybyeachonelimitswitchattheendofthetrackrope.Forbeingcapableonprincipletotakeintoconsiderationfurtherobstaclesinthetravelarea,thescrew-typelimitswitchhasbeenequippedwithfurthercontacts.Bytheunavoidableslipbetweenreturnpulleyandcrabtraversingrope,andbytheretensioningofthecrabtraversingrope,acorrectionofthescrew-typelimitswitchandthepositionindicatorwillbecomenecessary.Thiscorrectionshouldbemadeatleastonceadaywithstartofthenewshift.Forthispurposethecrabmustruntoapositionthatisknowntothecranedriverandfromwhichisknowntheexactdistanceuptotherespectiveendofthetrackrope(asreferencepositionwouldbesuitablearopecarrierortheconcreteplatform)[8].Incase,atthatpositionofthecrab,thevalueshownforthepositionofthecrabisnotinaccordancewiththeactualdistance,thenthescrew-typelimitswitchandthepositionindicatormustbecorrected.Forthispurposethecrabmustberunintoaposition,wherethepositionindicatorisshowingthesetdistance(e.g.atthefirstropecarrier50m).Assoonasthisfigureisappearingonthedisplay,crabtraversingmustbeinterruptedandthesynchronousbuttonwillseparatethereturnpulleyfromthescrew-typelimitswitchandthepositionindicatorwilllimitthecrabtraversingspeedtov<20％ofvrated.Thesynchronousbuttonmustbedepressedduringthewholesynchronizationprocedure.Thecrabthenrunstothereferencepointthathasbeensettothedisplay(e.g.thefirstropecarrier).MaintenanceBesidethegeneralmaintenanceandinspectionwork,andasisfurtherdescribedundertheSection“GeneralMaintenanceInstruction”and“Lubrication”,theownershouldtakecareofauniformrunningoftheropesintheBecoritlining.Assoonasirregularitiesoccur,thesecanbeeliminatedbyacorrectionofthealignmentofthedrivepulleyandofthereturnpulley.Forthispurposesettingscrewsarefittedtothepillowblocksofthedrivepulleyandofthereturnpulley.Bytheclampingsetincorporatedinthereturnpulley,thelattercanalsobeshiftedaxially.Thedrivepulleyofthecrab-traversingwinchisdesignedas2-groovedrivepulleylinedwithBecorit.DependingonthevaryingropetensionofthecrabtraversingropeinthetworopegroovesandthedifferentropeslipthereresultsadifferentwearingofBecoritlininginthetwogrooves.Adifferentgrooves[10].depthmeansalsoadifferentcircumferentialspeedandthisresultsforciblyinanincreasedropeslipandthereforeinaheavierwearingofthelining.Thereforethedrivepulleygroovesmustbecheckedfrequentlyfortheirdepth(bymeansofgauge).Withadepthdifferenceof2mmonegrooveistobeturneduntilthetwogrooveshaveagainthesamedepth[11].Turningspeedforcuttingis2to4m/sec.TheBecoritliningshouldbereplacedassoonastheremainingthicknesshascomedowntoapprox.20mm.Thiscorrespondstoatotalgroovedepthof40mmataliningthicknessof60mm.Unit22KomatsuD375ABulldozerNewwordsandexpressionsOutstandingProductivityStress-absorbingUndercarriagesOfferMightyTractionThesprocketsandidlersaremountedthroughelasticsupports,softeningshockstoboththemachineandtheoperator,causedwhenthemachinefrontmakesgroundcontact,followingtraveloverhardorrockyterrain.Sincetrackrollersarerigidlymountedonthetrackframes,theydonotoscillateandtheyallowtrackshoegrouserstobitethegroundwithnear-to-constantforce,increasingtractionandreducingshoeslippage.Thus,themachine’sforceiseffectivelyconvertedintotraction.AHigh-potencyEngineforPowerfulDozingandRippingTheSA6D170enginedeliversadynamicpowerof525HP(391kW)at1800RPMandatenacioustorqueof267kg-m(1,931ft-lb/2,618Nm).This,togetherwiththeheaviestmachineweightproducesthestrongestdrawbarpullof51.5tons(whenshoeslippingwithF2gear),makingtheD375Aasuperiorbulldozerinbothrippinganddozingproduction.HighBladeandRipperPerformanceAlargebladecapacityof17.3m3(semi-Udozer)and20.9m3(U-dozer)meansincreasedproduction(Figure22-1).High-tensile-strengthsteelcomprisingthefrontandsideofthebladeincreasesdurability.Thevariablegiantripperfeatureslongsprocketcenter-to-ripperpointdistance,makingrippingoperationeasyandeffectivealongwithgreatpenetrationforce(Figure22-2).BreakthroughsinFuelEconomyAutomaticlockupsystemiseffectivefordozingloosesoil.Whenmorepowerisneeded,especiallyinlong-distancedozingorhauling,turnontheLOCKUPswitchandthelockupclutchinthetorqueconverterisautomaticallyengagedordisengaged(inotherwords,directdriveortorqueconverterdriveisautomaticallyselected)dependingontherevolutionsofthetorqueconverteroutputshaft.Theresult:moreeffectiveuseofenginepowerwithlessfuelconsumption.TheKomatsuSA6D170EngineRealizedMinimumFuelConsumptionThisnewlydesignedenginefeaturesadirect-injectionsystem,turbochargerandaftercoolertomaximizefuelefficiency.Theengineismountedonthemainframethroughrubbercushionstominimizenoiseandvibration.Forfurtherconvenience,fueladjustmentisunnecessaryuptoanaltitudeof3000m(9,840ft).TheDualTiltDozer(option)reducesoperatoreffortwhileincreasingproductivity.1)Optimumbladecuttingangleforalltypesofmaterialsandgroundinclinationscanbeselectedonthegoforincreasedloadsandincreasedproduction.2)Digging,haulinganddumpingareeasierandsmootherwithlessoperatorfatigue.3)Increaseddozertiltangleandtiltspeedbytwicethatofaconventionalsingletiltsystem.MinimumDowntimeStress-absorbingundercarriagesextendservicelife.Rubbercushionssurroundthesprocketandidlershaftstosoftenshockscausedwhenthemachinegoesoverobstacles,thussignificantlyreducingoperatorfatigueandextendingcomponentlife.Uniquemodulardesignmakesiteasytoremovepower-traincomponentswithoutoilspillage.Thesealed,modulardesignallowsthepower-traincomponentstobemounted/dismountedwithoutanyoilspillage,makingservicingworkclean,smoothandeasy.Advancedmonitoringsystemhelpstopreventminorproblemsfrombecomingmajorones.Conditionsofbothcheck-before-startingitemsandcautionitemsappearontheliquidcrystalmonitoringpanel,preventingthedevelopmentofseriousproblems(Figure22-4).Thecontinuousconditioncheckallowstheoperatortoconcentratehisattentiononthecontrols.Unit23KawasakiPowerLoaderNewwordsandexpressionsUnit23KawasakiPowerLoaderJob-proven,RuggedCumminsEngineThisfour-cycle,six-cylinder,water-cooled,turbochargeddirect-injectionenginehasbeendesignedformaximumperformanceandefficiency.Itdevelopsaconsistentlyhightorqueacrossawiderangeofenginerpm’swhileutilizinganefficientfuel-airmixturecombustion,delivering450HP(gross)tomeetallloaderoperatingdemandsofitsclass[1].Alargefueltank(620ltr)enableslongoperatinghourswithoutrefilling.Computer-controlledAutomaticTransmissionNomoreannoyinggearshifts!OnceyouselectthedirectionandAUTOwiththedirectionalandspeedcontrollever,theoptimumenginerpm’sandspeed(forward:2nd,3rdand4th/reverse:2ndand3rd)areautomaticallyselectedbythecomputer-controlsystem(seeFigure23-2),leavingyoutoconcentrateonbucketloadingoperationsonly.DependableServiceBrakeBrakingisassuredwithdual-linehydraulically-actuated,fully-sealedwetmulti-discbrakes,sohighlyresponsivedependablebrakingisdeliveredtoallfourwheelswithlight-touchoperation[2].Andawear-resistantliningisusedforthediscstoprolongtheservicelife.(seeFigure23-3)ToughFrame,BoomandBucketCylinderBracketFullboxsectionmainframehasbeenstrengthenedtosupportengineandpowertraincomponent,whiletheboomandbucketcylinderbracketsaremadeofqualitythickplatestoresistshockandloadingstresses.SimplifiedChecksandMaintenanceOne-touchswing-upradiatorgrille——Tofacilitatecleaningtheradiator,theradiatorgrilleisfully-openedatthetop,particularlyusefulonsiteswherecloggingoccursandimmediatecleaningisneeded.Wide-openingenginecompartment——Theenginesidecoverscanbeopenedwider,makingiteasytochecktheengineandrelatedpartsfromtheground.Simplifiedengineoildrainage——Engineoildrainplugislocatedoutsidetheenginecompartmentforeasyaccesswithoutgettingdirty.Double-structureaircleaner——Thedoubleelementaircleanerfiltersthecontaminatedoutsideairtosupplypureairtotheengine.Accumulateddustisautomaticallyremovedwhentheenginestops.Sealedloaderlinkagepins——Allpinsarefullysealedwithgreasetoprovidedependableservicewithminimummaintenance.Metal-sealringsalsoextendthelifeofthepinsandbushings.AComfortableOperatorHousedinARuggedMachinePerformsatHisPeakMulti–adjustableoperator’sseat——The115ZIVprovidesawealthoffunctionalcomforts.Thebucketseatwitharmrestsisfullyadjustableforheight,positionandtilt,andthecriticalbalancebetweenseatlocation,visualposition,steeringwheel,pedalsandleversiscarefullydesigned.Thepaddinginsidethefabricseatcoverisdesignedtoabsorbextravibration.Lowernoise——Noiseinsidetheoperator’scompartmentisminimizedbytheextramarginofpowerintheCUMMINSengine,alargeexhaustmuffler,soundproofingurethanerubberlininginsidetheengineinsidetheenginesidecoversandreargrille,andvibration-absorbingrubbermountingonoperator’scompartmentfloor,maintainingidealclimateconditionsatalltimes.Amenitiesandarm-rest——Alltheaboveensurelastingcomfortduringlonghoursatthewheel.What’smore,manyextrafeaturessuchasadrinkholder,trays,storagebox,etc.arearrangedwithineasyreachoftheoperator.Acomfortableslidingandvertically-adjustedarm-restontherightsideoftheoperator’sseatreducesfatigueduringbusyboomandbucketoperations.Easy-accessoperatorcontrols——Naturallythedirectionalandgearshiftlever,acceleratorpedal,brakepedals,bucketandboomcontrollevers,handle-mountedsteeringwheelandselectorswitchesandbuttonsareergonomicallydesignedandeasytoreach.Single-leverdirectionalandgearshiftcontrol——Withasingleleverontheleftofthesteeringcolumn,alldirectionalandgearshiftchangesarebroughttoyouinstantly；justselectthedirectionbypullingthelevertowardyouforreverseorpushitawayforforwardsandturnthelevertothedesiredforwardorreversespeed[4].Forward:1st,2nd,3rdandAUTO(2nd,3rdand4thautomaticallychanged)Reverse:1st,2ndand3rd(2ndand3rdautomaticallychanged)Panoramiccab(option)——Anewpanoramiccab(option)notonlyprotectstheoperatorfromexternalhazardsbutalsoprovidesanexcellentworkingenvironment.Toensureexcellentvision,thefrontandrearwindshieldarecurvedglassandintermittentwindshieldwipersareprovided.Theoptimummixofcoolandwarmairisensuredwithanewairconditioningsystem(option).Thecabinteriorisanotherfeature;thefelt-linedceiling,thickrubber-mattedfloorandvariousamenitiesarecoordinatedinatastefulcolor.Light-touchsteeringandassuredloading——TheOrbitrolload-sensingsystemsupplieshydraulicpressuretothesteering(takespriorityoverloadingsystem)onlyifneededsothatlight-touchsteeringisensuredevenatlowenginespeeds.Whensteeringisnotrequired,thefulldischargefromthesteeroilpumpisappliedtotheloadingcircuitsothatpowerfulloadingisensuredforgreaterenergysavings.Assuredprecisionbraking——Inadditiontothebrake-onlypedal(right),thedeclutchpedal(left)isusedforprecisebrakingwhilethetransmissionisinneutralbyturningonthetransmissioncut-offswitch,thushighrpm’scanbemaintainedforbucketloadingoperations.Ofcourse,thispedalcanbeusedforbrakingonlywhenthetransmissioncut-offswitchisturnedoff,toensuresafeoperationonslopesorramps.At-a-glancemetersandgauges——Theexactconditionsofthemachinecanbeinstantlycheckedfromthemeters,gaugesandindicatorlightsontheinstrumentpanel;speedometer,enginewatertemp；Gauge,fuelindicator,airpressuregauge,enginehourmeter,andvariousotherwarningandindicatorlightsaswellasselectorswitchesandbuttons.PUS(power-upswitch)——TheboomcontrolleverisaccompaniedbyasmallPUSlevertoaccommodategearshiftsfrom2ndto1standviceversaforscoopingmaterialeasilywithouttakingyourhandoffthebucketcontrollever.Optimumbucketcontroldetent——Thebucketcontrolleverallowsafullbuckettobescoopedveryeasilybecauseadetentisactivatedatthepositionwherethebucketencountersextraloadwhileraisingtheboomsothebucketandboomcanmovesmoothlyandefficiently.Unit24KomatsuTruckNewwordsandexpressionsUnit24KomatsuTruckHigh-outputKomatsuSA6D140engine:The15.2-literpowerplantwithturbochargerandaftercoolerdevelopsamassiveoutputof488HP(364kW)at2100RPM.7-speed,fullyautomaticK-ATOMiCStransmission:TheK-ATOMiCS(KomatsuAdvancedTransmissionwithOptimumModulationControlSystem)automaticallyselectstheoptimumgearaccordingtovehiclespeed,engineRPMandtheshiftpositionyou’vechosen.Theresult:thebestgearforanydrivingsituation.Oil-cooledmultiple-discretarderandoptionalexhaustretarder:Thetruckcanbedeceleratedwithoutfrequentuseofthebrakes,allowingyoutotravelsaferathigherspeeds,evendownlong,steepslopes.ExcellentProductivity—PowerandSpeedontheSteepestInclinesLongwheelbaseandwidetread:Withanextra-longwheel-base,awidethreadandanexceptionallylowcenterofgravity,theHD325-6haulstheloadathigherspeedformoreproduction,anddeliverssupremedrivingcomfortoverroughterrain.Bigbody:Awidetargetareaof19m2(204sq.ft)makesforeasyloadingwithminimalsoilspillageandmoreefficienthauling.Smallturningradius:TheMacPhersonstruttypefrontsuspensionsystemhasaspecialframebetweeneachwheelandthemainframe.Thewiderspacecreatedbetweenthefrontwheelsandthemainframeincreasestheturningangleofthewheels.Thelargerthisturningangle,thesmallertheturningradiusofthetruck.AMoveStableRideinAMoreManeuverableTruckLowfuel-consumingengine:Highinjectionpressurecreatesanidealfuel-airmixtureformorecombustionefficiency,whiletheductilecast-ironpistonsgreatlyreducefrictionloss.Forevenmorecombustionefficiency,eachcylinderhasfourvalves—twoforintake,twoforexhaust.Thetwointakeports(botharehelicaltype)produceoptimumswirlforexcellentcombustion.Theexhaustgasissmoothlyandquicklyejectedfromthecombustionchamberthroughtheexhaustports.AllthishelpstomaketheKomatsu-builtengineafuelmiser.ExcellentFuelEconomyK-ATOMiCS—smoothacceleration/deceleration:Anelectronicallycontrolledvalveisprovidedforeachclutchpackinthetransmission,allowingindependentclutchengagement/disengagement.Moreover,itenablesanidealchangeinclutchmodulationpressureandtorquecut-offtiminginresponsetotravelingconditions.Theresultissmoothshiftingandresponsiveacceleration.EnhancedOperationComfortHydropneumaticsuspension:Allfourwheelshavehydropneumaticsuspensionwithafixedthrottledampercontrolvalvethatgreatlyreducespitching,rollingandbouncingoverroughterrain.Three-modehydropneumaticsuspension(optional):Tofurtherenhancethedrivingcomfort,automaticthree-modesuspensionisoptionallyavailable.Itenablestheoperatortoselectoneofthreecushioningeffects(SOFT,NORMALorHARD)dependingontheroadconditions,forimproveddampingcontrol[4].Study,refinedframe:Cast-steelcomponentsareemployedinthemainframeincriticalareaswhereloadsandshocksaremostconcentrated.Adjustment-freebrakes:Thefrontservicebrakesandtheparkingbrakeareadjustment-freecaliperdisctype[5].Easymaintenance:Greasingpointshavebeencentralizedatthreelocations.Fuelandengineoilfiltersarealsolocatedtogetherontheleft-handremotemount,foreasy,remoteinspectionfromtheground.Rigorousdumpbodydesign:Thedumpbodyismadeof130kg/mm2(184,900PSI)high-tensile-strengthsteelforexcellentrigidityandreducedmaintenancecosts.TheV-shapedesignalsoincreasesstructuralstrength.Thesideandbottomplatesofthedumpsectionarereinforcedwithribsforaddedstrength.Monitor:Amonitorsysteminformstheoperatorofanyabnormalityattwolevels:CAUTIONandEMERGENCY[6].Sincefailuresaredetectedbeforetheybecomecritical,theHD3256ismorereliableandsaferthanever.Payloadmeter:Inadditiontoaproduction-amountdisplay,thepayloadmeterindicatesloadingstatustotheloaderoperatorwithcautionlampsonthesideofthecab.Notonlyisoverloadingprevented,butthemachinecanbemorecloselycontrolledformoreproductivityandeconomy.Rockbody:Theoptionalrockbody,withreinforcementlinersfittedthroughoutthebodyinterior,isavailableforheavy-dutyrockloadingassignmentsatquarry,limestonemineandothertoughjobsite.Engineexhaustretarder:Itimprovessafetyandhaulingperformance.Three-modehydropneumaticsuspension(auto-suspension):Dampingforceisautomaticallyswitchedtooneofthreestages(SOFT,NORMALandHARD)accordingtoloadandroadconditions,foramorecomfortableandstableride.Monitorwithmaintenancecontrolfunction:Themonitorautomaticallychecksitemstobecheckedbeforestarting,sodailymaintenanceiscarriedouteasily.Filterandoilreplacementtimesarealsosuggestedformorefoolproofmaintenance.ROPS:Itprotectstheoperatorandthecabfromdamageshouldthetruckturnover.Unit25CAD/CAM/CAPPNewwordsandexpressionsUnit25CAD/CAM/CAPPComputeraideddesign(CAD)canbedefinedasusingcomputerstoaidtheengineeringdesignprocessbymeansofeffectivelycreating,modifying,ordocumentingthepart’sgeometricalmodeling.CADismostcommonlyassociatedwiththeuseofaninteractivecomputergraphicssystem.Theobjectoftheengineeringdesignisstoredandrepresentedintheformofgeometricmodels.GeometricmodelingisconcernedwiththeuseofaCADsystemtodevelopamathematicaldescriptionofthegeometryofanobject.Themathematicaldescriptioniscalledamodel.Therearethreetypesofmodels(wire-framemodels,surfacemodels,andsolidmodels,seeFig25-1).thatarecommonlyusedtorepresentaphysicalobjects.Wire-framemodels,alsocallededge-vertexorstick-figuremodels,arethesimplestmethodofmodelingandaremostcommonlyusedtodefinecomputermodelsofparts.Surfacemodelsmaybeconstructedusingalargevarietyofsurfacefeatures.Solidmodelsarerecordedinthecomputerresult;itispossibletocalculatemasspropertiesoftheparts,whichisoftenrequiredforengineeringanalysissuchasfiniteelementmethods,kinematicsordynamicstudies,andmassorheattransferforinterferencechecking.CADModelsinCADalsocanbeclassifiedasbeingtwo-dimensionalmodels,two-and-half-dimensionalmodels,orth