Windshieldwiperarmwithhemmeddistalend.docx

Windshieldwiperarmwithhemmeddistalend.docx

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Windshieldwiperarmwithhemmeddistalend

Windshieldwiperarmwithhemmeddistalend

CROSSREFERENCETORELATEDAPPLICATION

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FEDERALLYSPONSOREDRESEARCHORDEVELOPMENT

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REFERENCETOSEQUENCELISTING

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BACKGROUNDOFTHEINVENTION

1.FieldoftheInvention

Thisinventionrelatestoawiperarmforanautomotivewindshieldwipersystem.Moreparticularly,thisinventionrelatestoawiperarmoftheaforesaidcharacterofunitaryconstructionwithanarrow,thickenedfreeordistalendofadoublethicknessthatisformedbyhemming.

2.DescriptionofthePriorArt

Typicalpriorartwindshieldwiperarmassemblies10usedonmotorvehiclesasshowninFIGS.1through5normallyconsistofamountinghead12,retainerarm14andwiperorarmrod16,aswellas,atensionoracoilspring20.Themountinghead12istypicallymanufacturedofzincoraluminumdiecast.Typicallytheretainerarm14isformedfromsheetmetalandstampedinageneralU-shapedconfigurationasshowninFIGS.4and5.Thewindshieldwiperarmassembly10alsohasawiperblade（notshown）,whichhasasupportbracketsystemandwiperstripretainer（notshown）.Thewiperbladeispivotallyconnectedtothewindshieldwiperarmassembly10throughuseofahooklikeend17ofthewiperrod16whichengagesbetweentwolateralcheeksofthesupportbracketsystemofthewiperblade（notshown）.Thefitwiththesupportbracketrequiresasizingoperationonthewidthofthehooklikeend17sothatitwillproperlyfitbetweenthetwolateralcheeksofthesupportbracketitengages.Theconnectionthusformedguidesthewiperbladewiththewiperstripovertheglasswindshieldofthemotorvehicle.Thejointedconnectionandthesupportbracketsystemmakeitpossibleforthewiperstriptoadapttoacurvatureofthewindshield.Arequiredcontactpressureofthewiperstriponthevehiclewindshieldisattainedwithatleastthetensioncoilofthespring20whichbracesthemountinghead12andtheretainerarm14inconjunctionwiththewiperrod16throughatogglejoint21.

Theshapeoftheindividualcomponentsoftheretainerarm14isinfluencedbyvariousdemandsandstresses.Specifically,theyshouldbeastorsionallyrigid,deflection-resistant,andasnarrowinthefieldofviewaspossible,sothatthewiperbladecanbeguidedwithoutvibrationandundercontroloverthevehiclewindshieldyetpresentlittlehindrancetothefieldofview.Themountinghead12transmitsthedrivemomentfromthedriveaxisA-Atothewiperblade,viatheretainerarm14andthearmrod16.Italsoformspartofthetogglejoint21,bywayofwhichthemountinghead12isbracedwiththeretainerarm14bythetensionspring20andpressedinthedirectionofthevehiclewindow.Thegreatestforcesormomentsariseinthemountinghead12,bothparalleltothewindowandperpendiculartothewindow.Further,deformationsinthelowerregionoftheretainerarm14haveanespeciallystrongeffectovertheentirelengthandcancauseunevenwipingspeedsasaresultofaspringeffect.Themountinghead12andthefirstportionoftheretainerarm14mustthereforebeembodiedasespeciallydeflection-resistantandtorsion-resistant.

Inawipingmotion,theoutwardportionoftheretainerarm14movespartly,andthewiperorarmrod16movescompletely,throughthefieldofviewofthedriverandasaresulttheymustbemadenotonlytorsionanddeflectionresistant,butalsoespeciallynarrowsothattheyimpedeaslittleofthedriver'sviewaspossible.Further,theretainerarm14shouldbeshapedinsuchawaythatitisnotliftedawayfromthevehiclewindowbytheairflowacrossthewindshield.

Toaccommodatethesevariousrequirements,priorartwindshieldwiperarmassemblies10haveawidemountingheadthatmaybemadeofzincoraluminumdiecastorsheetmetalaswellasaretainerarm14thatisalsomadeofsheetmetalwhichisrelativelywideintheregionofthemountinghead12thatis,attheloweredge22ofthefieldofviewofthedriver.Often,thisportionoftheretainerarm14ismadewithaninvertedU-profilethatisopentowardsthewindowasshowninFIG.5.Suchprofilehasarelativelystrongresistancemoment,andisespeciallytorsionanddeflectionresistantinthisareawhilealsobeingabletoaccommodatethetensionspring20whichisconcealedintheU-profile.Intheoutwarddirectiontowardsthefreearmendoftheretainerarm14wheretheretainerarm14connectswiththewiperrod16,theretainerarm14taperssothatitisnarrowerinthefieldofviewofthedriverasshowninthecross-sectionofFIG.3.Overthefulllengthoftheretainerarm14,theprofilehasaconstantmaterialthickness,determinedbythesheetmetalthicknessused.Thisthicknessisdesignedinordertoaccomplishtheappropriatedimensionalstabilityunderthegreatestmaterialstressestobeexpectedwhicharebasicallybendingandtorsionstresses,specifically,perpendicularandparalleltothevehiclewindow.

Generally,thewiperrod16isformedofaprofileofconstantthicknessmaterialsolidflatstock,whichiseithercrimpedorriveted30asshowninFIGS.1and3totheretainerarm14.Thethicknessofthewiperrod16isafunctionofdriveandcontactforces,thelengthoftheretainerarm14,aswellastheresistantmomentstothewindshieldwiperarmassembly10.Furtherconsiderationsaretheeffectofwindengagementfacesaswellandmoreimportantly,theslenderstructureinthefieldofviewofthedriver.Generally,thematerialstressdemandsaregreatestattheconnectionpointofthewiperrod16totheretainerarm14andbecauseofthesmallcross-sectionalareaandunfavorableresistancemoments,thematerialthicknessisgenerallydeterminedbythestressrequirementattheconnectionpointbetweentheretainerarm14andthewiperrod16.Forthisreason,thewiperrod16itselfisgenerallyasolidstockformedofathickermaterialthantheretainerarm14thus,thearmrod16andretainerarm14arecombinedinasinglerigidassemblywhichrotatesalimiteddegreeaboutdriveaxisA-A.Asaresult,insomeapplications,thereisunnecessarilyhighconsumptionofmaterial,highmaterialcosts,andhighweight.

Furtherconsiderationstobemadeinthedesignofacompletewindshieldwipersystemistheassociatedwindshieldwashingsystemandconsiderationswhichneedtobemadewithrespecttothemountingofthesprayingdeviceonthehoodorthewindshieldwiperarmassembly10.Thewindshieldwashingsystemconsistsofawashingliquidreservoir,aswellasapump（notshown）,bywhichwashingliquidissprayedontothewindshieldtobecleanedbyasprayingdevice.Itisknownthatthesprayingdevicemaybestationarilyarrangedontheenginecompartmenthood.Further,thewindshieldcleaningsystem-sprayingdevicemaybefixedtothewindshieldwiperarmassembly10.Theadvantageoffixingthesprayingdevicetothewindshieldwiperarmassembly10isthatthewashingliquidissprayedimmediatelyinfrontofthewiperblade.InthepriorartembodimentillustratedinFIGS.1through5,themountingbracket26forattachingasprayingorwashernozzle28isrivetedtooneofthelegsoftheU-shapedretainerarm14.Insomepriorartembodimentsthemountingbracket26maybestampedoutoftheprofileoftheU-shapedlegoftheretainerarm14andlaterallyspacedwithrespecttotheplaneofthelegoftheU-shapedretainerarm14.Thisattachedstructureprovidesaverystabile,rigidmountingsurfaceforthesprayingnozzle28whichprovidesanattractive,compactassemblyinwhichthefluidlineorhose24canbedressedsubstantiallyentirelywithinthecavityoftheU-shapedretainerarm14andtherebybeoutofsightfromtheuser.

WithreferencetopriorartFIG.2,thedetailsofthesprayingorwashernozzle28areillustrated.Thewashernozzle28includesabodyportionandamountingflangeintegrallyformedtherewithformountingwashernozzle28withmountingbracket26.Thefluidline24isconnectedtoaninletnippletoprovidewasherfluidtoaninletport.Asaresult,asprayormistisexpelledfromanozzleportoftheoutletnipple.

Inordertosolvehighcostandhighweightproblems,somewindshieldwiperassembliesparticularlyteachtheuseofaretainerarmandwiperrodwhichcanbemadeofanumberofvariablemateriallayerswhicharefoldedupononeanotherinvariousregionsuntilthematerialthicknessrequiredfortheparticularcross-sectionisobtained.Athinmaterialisbentovermultipletimesbyapproximately180°inmultiplestepsinordertobraceeachlayer.Theadvantage,ofcourse,isfromarelativelythinsheetofmetal,differentmaterialthicknesscanbeobtainedindifferentregionsandthisthicknesscanbeadaptedexactlytodifferentstressesthatarise.Unfortunately,smallmaterialstresscracks,virtuallyinvisibletotheeye,canresultfromthesemultiplebendingoperationsandasaresult,suchminutecracks,iftheyoccurontheoutersurfaces,cancauseexcessivenoisebywindpassingthereoverwhenexposedtoahighwindstream.Further,obviously,themultiplelayersofmetalinordertoaccomplishtheappropriatesizerequirements,mayalsoresultinhighermaterialcostsaswellashigherweightsduetothemultiplelayerswhicharenecessaryinordertoprovidetheappropriatestructuralrigidityforthetorsionanddeflectionforcesthatareknowninselectiveareasofthewindshieldwiperassembly.Generally,toenabletheuseofmultiplelayerassemblies,athinnermaterialisusedinordertomakethemultiplefoldswhicharenecessarytoacquiretheparticularcross-sectionneededtoresisttheknowndeflectionandtorsionmo