Groundsmaster 4000 --D/4010--DHydraulic System Page 4 -- 20
Mow Circuit Cutting Deck Blade Braking
WhentheoperatorturnsthePTOswitchOFForifadeck
is raised with the PTO switch ON, PTO manifold sole-
noidvalve(S)isde--energizedcausingbypasscartridge
(LC1) to shift (refer to information in Mow Circuit in this
section).T hisshiftedcartridgeallowsoilreturnoutman-
ifold port P2. At the same time, solenoid valve (S) in its
neutralpositionpreventsanysenselineflowthroughthe
spool which causes the brake cartridge (LC2) to shift to
its neutral position blocking return flow from the deck
motor and slowing the cutting blades (Fig. 11).
Theinertiaoftherotatingcuttingblades,however,effec-
tively turns the deck motor into a pump causing an in-
creasein pressure as the flow from the motor comes up
against the closed brake cartridge (LC2). When this
pressurebuildstoapproximately600PSI(41 bar),relief
valve (RV2) opens which allows a small amount of hy-
draulic flow to return to tank through a manifold sensing
line (Fig. 12). This flow causes a pressure increase that
shifts brake cartridge (LC2) to once again allow oil flow
from the motor (Fig. 13). When return pressure drops
below 600 PSI (41 bar), relief valve (RV2) reseats and
causes LC2 to close again blocking return flow from the
deckmotortofurtherslowthecuttingblades.Thisaction
ofthebrakerelief valveopening andthe brakecartridge
shifting occurs several times in a very short time frame
as the blades finally come to a stop. Once the blades
have stopped, brake cartridge LC2 remains in the neu-
tral position to keep the deck motor from rotating.
Figure 11
PTO
MANIFOLD
PUMP FLOW
RETURN
Figure 12
PTO
MANIFOLD
PUMP FLOW
RETURN
Figure 13
PTO
MANIFOLD
PUMP FLOW
RETURN
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