Toro Groundsmaster 3320-D - Page 114

LowerCuttingDeck(orImplement)(continued)
Whenthecuttingdeck(orimplement)istobelowered,thecontrolvalvespoolis
movedforwardcausingthepilotvalvetoshiftopen.Thisshiftedvalveallowsa
returnpathfromtheliftcylinderstothereservoir(frontaxle)(Figure52).The
weightofthecuttingdeck(orimplement)causesthecylinderstoretractthus
loweringthecuttingdeck(orimplement).Asthecylindersretract,thepistons
drawhydraulicuidfromthereservoir(frontaxle)intothelowerportionofthe
liftcylinders.
Whenthecontrolvalveleverisreleased,theliftcontrolspoolreturnsto
thecenterpositionandcausesthepilotvalvetoshift.Fluidowby-passes
passesthroughtheliftvalveandontothereservoir(frontaxle)andliftcylinder
movementisstopped.
Counterbalance
Anadjustablecounterbalancevalveallowscuttingunitweighttransfertothe
machinetoimprovetraction.Onearlyproductionmachines,thecounterbalance
valveisincorporatedintheliftcontrolvalve.Laterproductionorupdated
machinesuseadifferentliftvalveandaseparatecounterbalancemanifold.
Changesintractionconditions(e.g.,movingupanincline)willcauseavalveshift
toslightlyliftorlowerthecuttingdecktoalterweighttransfer.Counterbalance
pressuresettingsaredependantonthecuttingdeckusedonamachine.Check
thetypeofcounterbalancesystemusedandrefertotheTractionUnitOperator’s
ManualorthecounterbalancekitInstallationInstructionsforcounterbalance
pressurerecommendations.
HydraulicSystem:HydraulicFlowDiagrams
Page5–30
Groundsmaster
®
3280-D/3320
05138SLRevB