Rev.AGroundsmaster 4000 --D/4010--D Hydraulic SystemPage 4 -- 15
Lower Cutting Deck
A four section gear pump is coupled to the piston (trac-
tion) pump. The third gear pump section supplies hy-
draulic flow to both the steering and lift/lower circuits.
Hydraulicflow from this pumpsectionisdelivered to the
two circuits througha proportionalflow divider that is lo-
cated in the fan drive manifold. This flow divider splits
pump flow approximately 50% for the steering circuit
and 50% for the lift/lower circuit.
Areliefvalve (RV1)located in the lift/lowermanifoldlim-
its lift/lower circuit pressure to 1600 PSI (110 bar). An
adjustable valve (RV2) in the lift/lower manifold main-
tains back pressure (counterbalance) on the deck lift
cylinders to allow some of the cutting deck weight to be
transferred to the traction unit to improve traction.
Each of the cutting decks (center, right and left) can be
loweredindependentlywiththeuseofthree(3)switches
on the armrest console. Pressing the front of a switch
provides an input for the TEC--5001 controller to lower
acuttingdeck.Thecontrollerprovideselectricaloutputs
to solenoids in the lift/lower manifold to allow appropri-
ate manifold valve shift to cause a deck to lower.
When the cutting decks are in a stationary position, all
solenoids in the lift/lower manifold are de--energized. In
this position, lift/lower circuit flow bypasses the lift cylin-
dersandisdirectedthrought helift/lowermanifold,oilfil-
ter and then to the traction charge circuit.
NOTE: To lower acuttingdeck,the operatormustbe in
the operator seat and the traction speed must be in the
Low speed (4WD) position.
Lower Center Cutting Deck
To lower the center cutting deck, the front of the center
console switch is d epressed. The switch signal is an in-
put to the TEC--5001 controller which provides an elec-
trical output to solenoid valve S6 in the lift/lower
manifold. Energized solenoid valve S6 shifts to allow a
passage for oil flow from the rod end of the center deck
lift cylinders. The weight of the cutting deck causes the
center deck lift cylinders to extend and lower the center
cutting deck. Oil from the extending cylinders flows
throughan orifice in the fitting at manifoldport C2 (.070)
tocontrolthedropspeedofthecuttingdeck.Flowisthen
directedthroughtheshiftedS6,valveRV2,outmanifold
port CH, to the oil filter and is then available for thetrac-
tion charge circuit.
Whenthecenterdeck switch is released,solenoid S6 is
de--energized and the lift cylinders and center cutting
deck are held in position.
Lower Right Cutting Deck
Tolowertherightwingdeck,thefrontoftherightconsole
switchispushedasaninputtotheTEC--5001controller.
The controller provides an electrical output to solenoid
valvesS1,S8andS9inthelift/lowermanifold.Theener-
gized solenoid valves shift to allow a passage for circuit
oil flow to the rod end of the right deck lift cylinder.
ShiftedS1prevents oil flow from bypassingtheliftcylin-
ders. Shifted S8 allows an oil path to the rod end of the
right lift cylinder to retract the lift cylinder and lower the
right cutting deck. Oil from the retracting cylinder flows
through the orifice in manifold port C6 (.063) to control
thedrop speedof the cuttingdeck. Flowisthen directed
through shifted S9, valve RV2, out manifold port CH, to
the oil filter and then to the traction charge circuit.
When the deck switch is released, the manifold sole -
noids are de--energized and the lift cylinder and right
cutting deck are held in position.
Lower Left Cutting Deck
To lower the left wing deck, the front of the left console
switchispushedasaninputtotheTEC--5001controller.
The controller provides an electrical output to solenoid
valvesS1,S3andS4inthelift/lowermanifold.Theener-
gized solenoid valves shift to allow a passage for circuit
oilflow to therodendof the left deck liftcylinder.Shifted
S1 prevents oil flow from bypassing the lift cylinders.
Shifted S3 allows an oil path to the rod end of the left lift
cylinder to retract the lift cylinder and lower the left cut-
ting deck. Oil from the retracting cylinder flows through
the orifice in manifold port C4 (.063) to control the drop
speed of the cutting deck. Flow is then directed through
the shifted S4, valve RV2, out manifold port CH, to the
oil filter and then to the traction charge circuit.
When the deck switch is released, the manifold sole -
noids are de--energized and the lift cylinder and left cut-
ting deck are held in position.
Cutting Deck Float
Cutting deck float allows the fully lowered cutting decks
to follow ground surface contours. Lift/lower manifold
solenoid valves S4 (left deck), S6 (center deck) and S9
(right deck) are energized when the decks are fully low-
ered.Theseenergizedsolenoidsprovideanoilpassage
toandfromthe lift cylinderstoallowcylinderandcutting
deck movement while mowing. Counterbalance pres-
sure (RV2) will affect deck float operation.
NOTE: If a deck is already fully lowered when the igni-
tion switch is moved from OFF to RUN, the deck willnot
be in float until the appropriate deck lift/lower switch is
momentarily pressed to lower.
Hydraulic
System
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