User manual

Groundsmaster 4000 --D/4010--D Hydraulic SystemPage 4 -- 19
Mow
A four section gear pump is coupled to the piston (trac-
tion)pump.Hydraulicflowforthemowcircuitissupplied
by two sections of the gear pump. The gear pump sec-
tion closest to the piston (traction) pump supplies hy-
draulicflowtothesidecuttingdecks,whilethenextgear
pump section supplies the front cutting deck.
Each cutting deck is controlled by a hydraulic manifold
equipped with a solenoid control valve (S), bypass car-
tridge(LC1),brakecartridge(LC2)andtwo(2)reliefcar-
tridges (RV1 and RV2). Circuit pressure can be
measured at port (G) of the hydraulic manifold for each
cutting deck.
NOTE: To engage the mow circuit, the operator must
be in the operator seat, the cutting deck(s)must be fully
loweredandthetractionspeedmustbeintheLow
speed (4WD) position.
PTO Not Engaged
Whenthe PTOswitchisOFF orifthe deck is raisedwith
thePTOswitchON,thePTOmanifoldsolenoidvalve(S)
is not energized and the solenoid spool is in the neutral
position. This solenoid spool in neutral allows a small
amountofhydraulicflowtoreturntotankthroughaman-
ifoldsensingline whichcausesapressureincreasethat
shifts bypass cartridge LC1. The pump flow is routed
throughshiftedLC1andoutmanifoldportP2.Brakecar-
tridge LC2 remains in the unshifted position to prevent
any return flow from the deck motor to keep the motor
from rotating.
Return flow from the f ront and right PTO manifolds is
routedthroughtheoilcooler,oilfilterandthentothegear
pump input. Return flow from the left PTO manifold pro-
vides supply for the right deck.
PTO Engaged
When the PTO switch is turned ON and the decks are
lowered, the PTO manifold solenoid valve (S) is ener-
gized by the TEC--5001 controller.This shiftedsolenoid
valve prevents any sense line flow through the valve
whichallowsthebypasscartridgeLC1tobeinitsneutral
position.Gearpumpflowenteringthemanifoldisrouted
out manifold port M1 and to the cutting deck motor. The
return flow from the deck motor re--enters manifold port
M2. The shifted solenoid valve (S) allows a small
amount of this return flow to return to tank through a
manifoldsensinglinewhichcausesapressureincrease
that shifts brake cartridge LC2. Hydraulic flow is routed
through shifted LC2, out manifold port P2, through the
oil cooler and filter and then is routed to t he gear pump
input. The deck motor continues to rotate as long as so-
lenoid valve (S) is energized.
Deck motor case drain leakage returns to the hydraulic
reservoir.
PTO Circuit Relief
Maximum mow circuit pressure is limited for each deck
by a relief valve (RV1) in the PTO manifold. The center
and left deck relief valves are set at 3000 PSI (207 bar)
and the right deck relief valve is set at 2000 PSI (138
bar).
Relief valve (RV1) and bypass cartridge (LC1) work to-
gether as a two stage relief. When increased circuit re-
sistance is met or if a cutting blade should strike an
object, the pressure increase is felt at the relief valve. If
the pressure should exceed the relief valve setting, the
reliefvalvewillopen,creatingasmallamountofhydrau-
lic flow to return totank through a manifold sensing line.
This flow causes a pressure increase that shifts bypass
cartridgeLC1anddivertscircuitflowawayfromthedeck
motor to manifold port P2 (Fig. 10). When circuit pres-
sure lowers, relief valve (RV1) closes which returns by-
pass cartridge LC1 back to its neutral position allowing
flow to return to the deck motor.
Figure 10
SOLENOID S ENERGIZED
RV1 SHIFTED
LC1 SHIFTED
DECK MOTOR STALLED
FRONT PTO
MANIFOLD
PUMP FLOW
RETURN
Hydraulic
System