Toro Groundsmaster 4500-D Series - Page 138

CuttingDeckBladeBraking(continued)
shift.Theshiftedreliefvalveremovestheowpathfromtheoriceatthelogic
cartridge,causingthelogiccartridgetoshiftandblockthereturnoilpathfrom
thedeckmotors(Figure52).
Theinertiaoftherotatingcuttingblades,however,effectivelyturnsthedeck
motorsintopumpscausinganincreaseinpressureastheowfromthemotors
comesupagainsttheclosedlogiccartridge(LC).Whenthispressurebuildsto
approximately104bar(1500PSI),thereliefvalveopenswhichallowsasmall
amountofhydraulicowpastthereliefvalve(Figure53).Thisowcausesa
pressureincreasethatshiftsthelogiccartridgetoonceagainallowoilowfrom
thedeckmotors(Figure54).Whenreturnpressuredropsbelow104bar(1500
PSI),thereliefvalvere-seatsandcausesthelogiccartridgetocloseagain,
blockingreturnowfromthedeckmotorstofurtherslowthecuttingblades.This
actionofthereliefvalveopeningandthelogiccartridgeshiftingoccursseveral
timesinaveryshorttimeframeasthebladesnallycometoastop.Once
thebladeshavestopped,thelogiccartridgeremainsintheneutralpositionto
keepthedeckmotorsfromrotating.
HydraulicSystem:HydraulicFlowDiagrams
Page5–36
Groundsmaster
®
4500-D/4700-D
19245SLRevA