Windshieldwiperdrivelinkagearmwithgrooves.docx

Windshieldwiperdrivelinkagearmwithgrooves.docx

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Windshieldwiperdrivelinkagearmwithgrooves

Windshieldwiperdrivelinkagearmwithgrooves

BACKGROUNDOFTHEINVENTION

1.FieldoftheInvention

Thisinventionrelatestoawindshieldwipersystemand,moreparticularly,toawindshieldwipersystemwhichutilizesatleastoneflexiblememberwhichbendsorflexestocompensateforcompressionloadsinexcessofapredeterminedload.

2.DescriptionoftheRelatedArt

Inthefieldofwindshieldwipersystems,wiperarmshavingwiperbladesthereonaredrivenfromaparkposition,wherethebladesareoftensituatedateitherthebottomoforbelowawindshieldofavehicle,throughaninwipeposition,toanoutwipeposition.Duringnormalwipingoperations,thebladesoscillatebetweentheinwipeandoutwipepositionstocleanthewindshieldofdebrisorparticles,suchasice,snoworotherdebris.Itisnotuncommonthatsnoworicecanaccumulateonthewindshieldandpreventthewiperbladesfrom,forexample,fullyretractingfromtheinwipepositiontotheparkpositionwhenauseractuatesawiperswitchtoanoffposition.

Whenthedebrisblocksthewiperarmsandblades,aconsiderableamountofstressisimpartedonthewiperlinkageanddrivemotorwhichdrivestheblades.Forexample,amotordrivelink,whichcouplesthedriveshaftofthemotortothedrivelinkagewhichdrivesthewiperarms,oftenexperiencesacompressiveforce.Thelinkagemembersofthewipersystemshaveinthepastbeenstiffenedtoreduceexpansionandshrinkageinordertoavoidchangingthewipepatternrequirementsforthevehicles.However,infreezing,snowyweather,thesnowandicepacksatthebottomofthewindshieldcausesarestrictioninthemovementinthewiperarmandblade.Becauseoftherigidityofthemotordrivelink,thehousingwhichhousesthedrivegearsofthedrivemotormaycrackorbreak.Ithasalsobeenexperiencedthatoneormoredriveplateswhichdirectlyorindirectlycouplethedrivelinktootherlinkagehavebeenknowntofractureorcrack.

U.S.Pat.Nos.6,148,470and6,381,800illustrateacompositearm,whichareincorporatedhereinbyreferenceandmadeaparthereof.Benefitsofthoseinventionsaretaughtinthearticle“ANovelUseofaCompositeMaterialtoLimittheLoadsinWindshieldWiperSystems”,Penrod,etal.,Copyright2001SocietyofAutomotiveEngineers,Inc.,whichisincorporatedhereinbyreferenceandmadeaparthereof.

Accordingly,whatisneededisasimple,yeteffective,linkagesystemwhichutilizesoneormorelinkagearmshavingarelativelylowmodulusofelasticitywithrelativelyhighelongationandfatiguepropertiestofacilitateavoidingtheproblemsofthepast.

SUMMARYOFTHEINVENTION

Inoneaspect,thisinventioncomprisesawindshieldwiperdrivelinkageforuseinawipersystemcomprisingapluralityoflinkagearms,atleastoneofsaidpluralityoflinkagearmscomprisingacompositeflexiblearmwhichbendstofacilitatepreventingdamagetocomponentsinthewipersystemwhenacompressiveloadappliedtoatleastoneofthepluralityoflinkagearmsexceedsapredeterminedloadasaresultofafatiguecondition,theatleastoneofsaidpluralityoflinkagearmscomprisingapluralityofgroovesoneachendtofacilitateprovidinganinterlockingjointwhenaconnectorisovermoldedontoeachend.

Inanotheraspect,thisinventioncomprisesawipersystemcomprisingafirstwiper,asecondwiper,awindshieldwiperdrivelinkagecoupledtosaidfirstandsecondwipers,adrivemotorcoupledtothewindshieldwiperdrivelinkage;andthewindshieldwiperdrivelinkagecomprisingapluralityoflinkagearmscoupledtothefirstandsecondwipersandthedrivemotor,atleastoneofthepluralityoflinkagearmscomprisingacompositeflexiblearmwhichbendstofacilitatepreventingdamagetocomponentsinthewipersystemwhenacompressiveloadappliedtotheatleastoneofthepluralityoflinkagearmsexceedsapredeterminedloadasaresultofafatiguecondition,theatleastoneofthepluralityoflinkagearmscomprisingapluralityofgroovesoneachendtofacilitateprovidinganinterlockingjointwhenaconnectorisovermoldedontoeachend.

Otherobjectsandadvantagesoftheinventionwillbeapparentfromthefollowingdescription,theaccompanyingdrawings,andtheappendedclaims.

BRIEFDESCRIPTIONOFACCOMPANYINGDRAWINGS

FIG.1isageneralschematicviewofawiperbladedriveandlinkingsysteminaccordancewithoneembodimentoftheinvention;

FIGS.2A–2DareillustrationsofthewiperbladeassemblyofFIG.1asitisdrivenfromanoutwipepositiontowardsinwipeandparkpositions;

FIG.3isaperspectiveviewofaflexiblememberinaccordancewithoneembodimentoftheinvention;

FIG.4isafrontviewoftheflexiblemembershowninFIG.3;

FIG.5isaplanviewoftheflexiblemembershowninFIG.3;

FIG.6isafragmentarysectionalviewofanendcapsituatedontheflexiblemember;

FIG.7isaviewsimilartoFIG.6showingapluralityofshearareastoenablethecaptoseparatefromtheflexiblememberwhenashearstressexceedsapredeterminedamount;

FIG.8Aisasectionalviewtakenalongtheline8A—8AinFIG.6;

FIG.8BisasectionalviewsimilartoFIG.8Ashowingaflexiblememberwithroundedcorners;

FIG.9isgraphicalrepresentationofarelationshipbetweenacompressiveloadfortheflexiblememberrelativetothelengthofthememberasitshortensandflexeswhenthecompressionloadexceedsapredeterminedamount;

FIG.10isanillustrationofanotherflexiblememberinaccordancewithanotherembodimentoftheinvention;

FIG.11isaillustrationoftheflexiblemembershowninFIG.10showingashortenedlengthL4;

FIG.12isasectionalviewtakenalongtheline12—12inFIG.10;

FIG.13isasectionalviewtakenalongtheline13—13inFIG.11;

FIG.14isadetaileddrawingofaflexiblearm;

FIGS.15Aand15Baredrawingsoffirstandsecondendsrespectivelyofaflexiblearm;

FIG.16isadrawingofaflexiblearmlookinginthedirection16—16ofFIG.14,

FIG.17isasideviewofacompositelinksocketattachment;

FIG.18isaplanviewofacompositelinksocketattachment;

FIG.19isaperspectiveviewofanotherembodimentoftheinvention;

FIG.20AandFIG.20Billustrateanotherembodimentoftheinvention;

FIGS.21Aand21Billustrateloadcharacteristicsoftheinvention;

FIG.22isaviewillustratinganothertest;

FIG.23isagraphillustratingvariousfeaturesoftheinvention;and

FIG.24isanothergraphillustratingfurtherloadcharacteristicsoftheinvention.

DETAILEDDESCRIPTIONOFTHEPREFERREDEMBODIMENTS

ReferringnowtoFIGS.1and2A–2D,awindshieldwipersystem10isshowncomprisingafirstwiper12andasecondwiper14forwipingawindshield16.Thewiper12comprisesawiperarm12aandblade12b,andwiper14comprisesawiperarm14aandblade14b.

Thewipersystem10furthercomprisesawindshieldwiperdrivelinkageorlinkingmeans18comprisingafirstlinkarm18onwhichadrivemotor20isfastenedtheretobyconventionalmeans,suchasaweld,nutandbolt,orthelike.Noticethattheframelink18comprisesafirstpivothousing21andasecondpivothousing22whichissecuredthereto.Thehousings21and22compriseafirstrotatablepivothousingshaft21aandasecondrotatablepivothousingshaft22awhicharedrivinglycoupledtowiperarms12aand14a（showninphantominFIG.1）,respectively.

Thefirstrotatablepivothousingshafts21aiscoupledtoafirstend24aofadriveplate24.Likewise,thepivothousingshaft22aissecuredtoafirstend26aofaseconddriveplate26,asbestillustratedinFIG.1.Anoperatingor“slave”link23couplesasecondend24boffirstdriveplate24toasecondend26bofseconddriveplate26suchthatthedriveplates24and26operatesynchronouslytorotatablydrivethepivothousingshafts21aand22ainthedirectionofarrowA,therebydrivingthewiperblades12band14b.

Thelinkageorlinkingmeans18furthercomprisesamotordrivelinkorflexiblearm28havingafirstend28acoupledtothesecondend24bofthedriveplate24.Themotordrivelinkorflexiblearm28furthercomprisesasecondend28bwhichiscoupledtoanoutputshaft20aofmotor20viaacrankarm30.Inthisregard,thecrankarm30comprisesacrankarmball（notshown）andthedriveplate24comprisesadriveplateball（notshown）.

Thearm28comprisesanelongatedrectangularmember29（FIGS.3–5）comprisingasocket32andsocket34whichareover-moldedthereon.AsbestillustratedinFIGS.3–6,thefirstend28aofmotordrivelinkorflexiblearm28comprisesthesocket32formountingontothedriveplateball（notshown）ondriveplates24,andsecondend28bofmotordrivelinkorflexiblearm28comprisesthesocket34forreceivingcrankarmball（notshown）oncrankarm30.AsbestillustratedinFIGS.3–7,thefirstandsecondends28aand28bcomprisethesockets32and34,respectively.Noticethatsocket32（FIG.6）definesasocketarea40,respectively.IthasbeenfoundthatitisdesirabletoalignthecenterlineCL（FIG.5）withtheaxisofshafts20a,22aand24awhenthewipers12and14areintheparkposition.

AsbestillustratedinFIGS.2A–2Cand3,flexiblearm28definesalengthL1,whichintheembodimentbeingdescribedisinexcessof250mm.Duringafatiguecondition,whenthecompressiveloadappliedtothearm28exceedsapredeterminedload（suchasatleast30percentofamaximumworkingloadofflexiblemember28asdefinedbelow）,theflexiblearm28beginstoflexorbend.Thiscausestheflexiblearm28toshortentoalengthL2,illustratedinFIG.2D,andthislengthL2isshorterthanlengthL1.AsillustratedinthegraphsshowninFIG