ARCHIVES HISTORIQUES
DELACOMMISSION
COLLECTION RELIEEDES
DOCUMENTS "COM"
COM(73)2091
Vol.1973/0376

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COMMISSION OFTHEEUROPEAN COMMUNITIES
COM(73)2091 final
Brussels.18December 1973
Amending oftheproposalforaDirective ontheapproximation ofthe
-lawsoftheMemberStatesrelatingtocertaincomponents and
characteristics ofwheeledagricultural tractors
■■ ■ I III I I»■ I!...- ■■ )■■
(Amendment presented bytheCommission totheCouncil
pursuanttoArticle149tsecondparagraph ,oftheEEC
Treaty) > .
•• - >
C0II(72)2091final

Explanatory memorandum
1.GENERAL
Intotheframework formed "bytheCommunity-wide type–approval
procedure whichwasthesubjectoftheDirective approved by
theCouncilon19December 1972,isto"befittedawholeseries
ofspecificdirectives concerning technical requirements and
methodsofcheckingtowhichwheeledagricultural tractors are
to"besubjectwhenEKCtype-approval isappliedfor.
Aspartofthatprocedure ,theCommission forwarded totheCouncil
on23July1968aproposalforaDirective ontheapproximation
ofthelawsoftheMemberStatesrelatingtocertaincomponents
andcharacteristics ofwheeledagricultural tractors''.
Asregardstherequirements relatingtothefieldofvision
whicharethesubjectofTitleXIIoftheAnnextotheabove-
mentioned proposalforaDirective ,theCommission ,inviewof
thefactthat,ithasnotyetbeenpossibletoformulate the
generalrequirements relatingtothefieldofvisionofmotor
vehiclestowhichitwasproposedtomakereference ,andthe
factthatatechnical solution wasestablished forthefieldof
visionofagricultural tractors ,thoughtitappropriate toamend
itsoriginal proposaltysubmitting technical requirements
intendedtoproviding aCommunity solutionforthischaracteristic .
OJNoC125,28November 1968,page37

-2-
II.COMiDM 1OFTHEPROPOSAL TORADIK5CTIVE
ThenewTitleXIIprovides -thatalltractors must "besoconstractcd
andecfuippcd astoensurethatthedriverhasanadequatefield
ofvisioninalltheusualconditions ofroadtrafficorworkin
thefields.Detailed requirements laydowntheconditions tobe
fulfilled forthefieldofvisionto"beconsidered adequate .
Inparticular ,aprocedure isprescribed fordelimiting masked
zonesasareanalternative mathematical method,andrequirements
relatingtothetransparent areaofthewindscreen andtowindscreen
wipersiffitted.
ThetextofTitleXIIoftheoriginal proposalistherefore
replaced bythefollowing :

TITLE XII
ÏTELDOFVISIOÎT
EEFIITITIOrrS AEDR5QUIRSITSNTS RELATING TOCONSTRUCTION
AMDCHUCKING '
1.DEFINITIONS
l.l.Ficld ofvision
"Fieldofvision"meansallforward andiidoward directions in
whichthedriverofthetractor oansee.
1.2.Référencé point
"Reference point"meanstheconventionally fixedposition ofthe
tractordriver'seyes,whicharenotionally locatedatasingle
point.Thereference pointissituatedintheplaneparallelto
thelongitudinal medianplaneofthetractorandpassingthrough
thecentreoftheseat,700mmvertically abovethelineof
intersection ofthatplaneandthesurfaceoftheseatand270mm
inthedirection ofthepelvicsupportfromthevertical plane
tangenttothefrontedgeofthesurfaceoftheseatand
perpendicular tothelongitudinal medianplaneofthetractor
(Figurel).
1.3•Hémicycle ofvision
"Heinicycle ofvision"meansthesemicircle described "bythe
radiusof12maboutapointsituatedinthehorizontal plane
oftheroadvertically "belowthereference pointinsuchaway
thatthearcofthesemicircle ,asviewedinthedirection of
motion,liesinfrontofthetractor,andthatthediameter
delimiting theheinicycle isatrightanglestothelongitudinal
axisofthetractor(Figure2).
1.4.Maskedzones
"Maskedzones"meansthehorizontal ,surfacesintheplaneof
theheaioycle ofvisionwhichcannot/"beseenfromthereference
pointowingtostructures forminganinherentpartofthetractor.

1.5.Maskingeffect
"Maskingeffect"neansthechordsofthesectorsofthehomicycle
ofvisionwhichcannotheseenowingtostructural components ,
e.g.,roofpillars.
1.6.Sectorofvision
"Sectorofvision"meanstheportionofthefieldofvision
delimited :
1.6.1.upwards
byahorizontal planepassingthroughthereference point;
1.6.2.intheplaneoftheroad,
"bythezonelyingoutsidethehemicycle ofvision,and
formingthecontinuation oftheseotorofthehemicycle
ofvision,whose9»5achordisperpendicular totheplane
paralleltothelongitudinal medianplaneofthetractor
passingthroughthecentreofthedriver'sseat,andi3
"bisected "bythatplane.
1.7.Fieldcovered "bythewindscreen wipers
"Fieldoovered "bythewindscreen wipers"meanstheareaof
theoutersurfaceofthewindscreen swept "bythewindsoreen
wipers.
2.CONSTRUCTION AMDCHECKING HEOTIEEMSHTS
2.1.General
Thetractormust "beconstructed andequippedinsuchawaythat
inroadtrafficthedriverhasanadequatefieldofvisioninall
theusualroadandatmospheric conditions .Thefieldofvision
isconsidered adequate whenthefollowing requirements are
fulfilled .
2.2.Checking ofthefieldofvision
2.2.1.Procedure fordetermining maskedzones
2.2.1.1 Thetractormust "beplacedonahorizontal surfacemaroom,
whiohcan"bedarkened ,inaccordance withFigure2.
Placeapointlightsourceatthereference pointinorder
todetermine theextentofmaskedzonesappearing intheplan«
ofthohemicyolo ofvision.

-3-
2.2.1.2.Themaskedsonesasdofinedinitem1.4«mustnotoverlap
hemicycle ofvision.
2.2.1.3.Themaskingeffectreferredtoinitem1.5.maynotexceed
thevaluesgiveninFigure3"bythelowestseparation curb
illustrated inthegraphinthatFigure.
2.2.1.4.Ifeskingeffectsduetoadjacentstructural components ,over
80aminwidthmust "bepositioned insuchawaythatthe
linejoiningthecentresoftheohordsofthesectorsof
thehemicycle ofvisionwhichcannotheseeni3notless
than2.50minlength.
2.2.1.5.Theremaybenomorethansixmaskingeffectsinthehemicycle
ofvisionandnomorethantwoinsidethesectorofvision
definedinitem1.5.
2.2.1.6.lfe.sid.ngeffectshavingvalues "betweentheupperandlower
separation curbsinthegraphinFigure3arepermittedif
thestructural components causingthemcannotbeshapedor
positioned otherwise .Theremaybenotmorethantwomasking
effectsofthiskind,andtheymustnotbewithinthe
sectorofvision.
2.2.1.7.Obstacles tovisionduetothepresence ofarear-vxew mirror
ofanapproved typearedisregarded .
2.2.2.Mathematical determination ofmaskingeffects
2.2.2.1.Asanalternative tothecheckreferredtoinitem2.2.1.,
ttheacceptability ofmaskingeffects maybeverified
mathematically .Therequirements ofitems2.2.1.4.and
2.2.1.5.applyasregardsthedistribution ofmasking
effeotsaccording totheirnumber.
2.2.2.2.Forbinocular visionandinter-ocular distance of65mmthe
maskingeffectisgivenbytheformula
–=2?-χ12.000
a
inwhich:
aisthedistance inmillimetres betweenthecomponent
obstructing vision .andthereference pointmeasured
alongthevisualradiusjoiningthereference point,
thecentreofthecomponent andtheperimeter ofthe
hemicycle ofvision.
bisthewidthinmillimetres ofthecomponent obstructing
visionmeasuredhorizontally andperpendicular tothe
visualradius.
2.2.2.3.Thomaskingeffectsdetermined bytheprocedure specified
initem2.2.2.2.shallnotexceed60mm.Two1200mm
maskingeffectsarepermitted ,however,providedthat
theyareoutsidethesectorofvisionandarccaused
bycomponents whichcannotbeshapedorarranged otherv/ise.

-4-
2.3.Transparent areaofthewindsoreen .
rIfthetractorisprovided withawindscreen ,thetransparent
areathereofmustbesuchthattherequirements ofitem2
aresatisfied .
2.4.Windscreen wipers.
2.4.1.Ifthetractorisprovided withawindsoreen itcrustalsobe
equipped withmotor-driven windscreen wipers.Thefield
coveredbythewindscreen wipersmustensureunobstructed
forwardvisioncorresponding toatleast8moftheohord
ofthesectorofvision.
2.4.2.Therateofoperation ofthewindscreen wipersmistbeat
least20cyclesperminute.

-5-
•y/NS
cs-y//\!>C//\v\///\K^ ■ */
./
/ Γ:·.γ:Χ"·*^

6–
\/ /
\/Sectorofvision
I ^\Referencepoint
i .•. ■'
•---–*' Tp-j?

MASKINGEPfECTONTIBHEMXCYCLE OFVISION
(EYESCOINCIDE ATTHEREFERENCE POINT)
Examples
Comment
Acceptable
Unacceptable
Unacceptable insectorof
vision "butacceptable
outsideitincertaincases.
Widthofstructural component obstructing vision,measure
alongthevisualradius.
V'v
'" 1iro
'\&"
i\\\v\\\V\°,MC/>s. Limitofmaskingeffect
U\\\VNVV"
-! •" –outèidethe
J sectorofvision
j insidethesector
1 ofvision
| 5«^
'1í!
i ; t
I » » – ..–"~~r~m
1 ",r,w tiOU tSOO J ^
Distancebetweenthestructural componentobstructing visionand
thereference -point(mm).Width Distance Maskingeffect
100 1000 1.2
2401600 1.6
...1601200 1.6
Figure3