user manual

Groundsmaster 4100--D Hydraulic SystemPage 4 -- 17
Raise Cutting Deck
A four section gear pump is coupled to the piston (trac-
tion) pump. The third gear pump section supplies hy-
draulicflowtothelift/lowercontrolvalveandthesteering
control valve. Hydraulic flow from this pump section is
delivered to the two circuits through a proportional flow
divider. The gear pump takes its suction from the hy-
draulic reservoir.
When the cutting deck is in a stationary position, flow
from the gear pump is by--passed through the lift/lower
control valve, counterbalance manifold, oil filter and
traction charge circuit.
To raise the cutting deck, the center lift lever on the lift/
lowercontrolvalveis pulledtoallowvalveshiftinthelift/
lower control valve. This valve change allows hydraulic
pressure to the rod end of the front deck lift cylinders,
causingthecylinders toretract.Asthecylinders retract,
thecuttingdeckraises.Oilfromthepistonendofthecyl-
indersreturnstothehydraulicreservoir.Whentheliftle-
veris released,the liftcylindersand cuttingdeckis held
in position.
Toraise awing deck,the appropriate liftlever onthelift/
lowercontrolvalveis pulledtoallowvalveshiftinthelift/
lower control valve. This valve change allows hydraulic
pressure to the piston end of the wing deck lift cylinder
andcausesthecylindershafttoretract,raisingthe wing
deck. Oil from the rod end of the cylinder flows to the
tractionchargecircuit.Whentheliftleverisreleased,the
lift cylinder and wing deck is held in position.
Anadjustablecounterbalancevalve(CB)inthecounter-
balance manifold maintains back pressure on the deck
lift cylinders to allow some of the cutting deck weight to
be transferred to the traction unit to improve traction. A
reliefvalvelocatedinthelift/lowercontrolvalvelimitslift/
lowercircuitpressureto1500PSI(103bar).Excesscir-
cuit flow is routed to the oil filter and then to the traction
charge circuit.
Hydraulic
System