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Groundsmaster 4500--D/4700--D
Hydraulic System (Rev. A)
Page 4 -- 13
Raise Cutting Units
A three section gear pump is coupled to the piston (trac-
tion) pump. The gear pump section (P3) farthest from
the piston pump supplies hydraulic flow to the lift/lower
control valve and the steering control valve. Hydraulic
flow from this pump section is delivered to the two cir-
cuits through a proportional flow divider. The gear pump
takes its suction from the hydraulic reservoir. Maximum
lift/lower circuit pressure (1500 PSI) is limited by a relief
valve in the power down and traction assist control man-
ifold (RV7).
On the Groundsmaster 4500--D, a single lift lever is used
to lift and lower the five cutting decks. The Groundsmas-
ter 4700--D has three lift levers to control the cutting
decks: the center lever is for the five center decks, the
left lever controls the left, rear deck, and the right lever
controls the right, rear deck.
Pressure to the lift/lower control valve can be monitored
at a port on the end of the gear pump
.
When the cutting units are in a stationary position, flow
from the gear pump is by--passed through the lift/lower
control valve, power down and traction assist control
manifold, oil filter, and traction charge circuit.
To raise the center five cutting decks, the lift lever on the
lift/lower control valve is pulled to allow valve shift in the
lift/lower control valve. This valve change allows hy-
draulic pressure to the rod end of the lift cylinder and
causes the shaft to retract, raising the cutting units. Oil
from the piston end of the cylinder flows to the traction
charge circuit. When the lift lever is released, the lift cyl-
inders are held in position.
To raise a side cutting unit on the Groundsmaster
4700--D (deck #6 or #7), the appropriate outer lift lever
on the lift/lower control valve is pulled to allow valve shift
in the lift/lower control. This valve change allows hy-
draulic pressure to the rod end of the cylinder and
causes the lift cylinder shaft to retract, raising the cutting
unit. Oil from the piston end of the cylinder returns to the
traction charge circuit. When the lift lever is released, the
lift cylinder is held in position.
An adjustable counterbalance valve (RV1) in the power
down and traction assist control manifold maintains
back pressure on the lift cylinders. This counterbalance
pressure transfers cutting unit weight to the machine to
improve traction. Excess circuit flow is routed to the oil
filter and then to the traction charge circuit.
Figure 11
#4 Deck
#1 Deck
#5 Deck
#7 Deck
(GM4700)
#6 Deck
(GM4700)
#3
Deck
#2
Deck
CUTTING DECK LOCATIONS
F
R
O
M
G
EAR
PUMP
(P
3)
FROM
TRACTION
CIRCUIT
CHARGE
C
IRCUIT
RAISE DECK #6 SHOWN
GM 4700--D
2200
PSI
Figure 12
Hydraulic System
Summary of Contents for Groundsmaster 4500-D
Page 1: ...Form No 02104SL Rev E Groundsmaster 4500 D 4700 D Original Instructions EN ...
Page 4: ...NOTES _ ...
Page 6: ...Groundsmaster 4500 D 4700 D This page is intentionally blank ...
Page 8: ...Groundsmaster 4500 D 4700 D This page is intentionally blank ...
Page 14: ...Groundsmaster 4500 D 4700 D Page 1 6 Safety This page is intentionally blank ...
Page 126: ...Groundsmaster 4500 D 4700 D Hydraulic System Rev A Page 4 88 This page is intentionally blank ...
Page 226: ...Groundsmaster 4500 D 4700 D Page 7 12 Chassis This page is intentionally blank ...
Page 261: ...Rev D Page 9 13 This page is intentionally blank ...
Page 277: ...Rev D Page 9 29 Serial Number Above 230000000 Engine Wire Harness Groundsmaster 4500 D 4700 D ...