Raise Cutting Deck Circuit - Toro Groundsmaster 4000-D Service Manual

Raise Cutting Deck Circuit

A four section gear pump is coupled to the piston (trac-
tion) pump (Fig. 10). The third gear pump section sup-
plies hydraulic flow to the lift/lower circuit, the engine
cooling fan circuit and the traction charge circuit.
A relief valve (RV2) located in the combination manifold
limits lift/lower circuit pressure to 1600 PSI (110 bar). An
adjustable pressure relieving valve (PR) in the combina-
tion manifold maintains back pressure (counterbalance)
on the deck lift cylinders to allow some of the cutting
deck weight to be transferred to the traction unit to im-
prove traction.
Each of the cutting decks (center, right and left) can be
raised independently with the use of three (3) lift
switches on the armrest console. Pressing the rear of a
switch provides an input for the TEC controller to raise
a cutting deck. The controller provides electrical outputs
to solenoids in the combination manifold to allow ap-
propriate hydraulic valve shift to cause a deck to raise.
When the lift/lower circuit is not being used (all lift
switches in the neutral position), solenoid valve S1 in the
combination manifold is not energized and gear pump
section oil flow is directed toward the engine cooling fan
motor.
NOTE: To raise a cutting deck, the operator must be in
the operator seat.
Raise Center Cutting Deck
To raise the center cutting deck, the rear of the center
console lift switch is depressed. The switch signal is an
input to the TEC controller which provides an electrical
output to solenoid valves S1 and S5 in the combination
manifold. The energized solenoid valves shift to allow a
passage for circuit oil flow to the barrel end of the center
deck lift cylinders. Shifted S1 allows gear pump section
oil flow to be available for the lift/lower circuits. Shifted
S5 allows an oil path to the barrel end of the front lift cyl-
inders causing the lift cylinders to extend and raise the
center cutting deck. Check orifice OR5 under the fitting
in manifold port C2 allows oil flow to bypass the orifice
when the center deck is raising. An orifice in manifold
port OR4 (.040) exists to control the raise speed of the
cutting deck.
When the lift switch is released, the manifold solenoids
are de--energized and the center deck lift cylinders and
center cutting deck are held in position.
Raise Right Cutting Deck
To raise the right deck, the rear of the right console lift
switch is depressed as an input to the TEC controller.
The controller provides an electrical output to solenoid
Groundsmaster 4000--D/4010--D
valves S1, S7 and S9 in the combination manifold. The
energized solenoid valves shift to allow a passage for
circuit oil flow to the barrel end of the right deck lift cylin-
der. Shifted S1 allows gear pump section oil flow to be
available for the lift/lower circuits. Shifted S7 and S9 al-
low an oil path to the barrel end of the right lift cylinder
to extend the lift cylinder and raise the right cutting deck.
Orifice OR6 (.063) controls the raising of the cutting
deck. Check orifice OR7 is bypassed when raising the
right cutting deck. Oil from the extending cylinder is di-
rected through S8 (de--energized), to the oil filter and
then to the traction charge circuit.
When the lift switch is released, the manifold solenoids
are de--energized and the lift cylinder and right cutting
deck are held in position.
Raise Left Cutting Deck
To raise the left deck, the rear of the left console lift
switch is depressed as an input to the TEC controller.
The controller provides an electrical output to solenoid
valves S1, S2 and S4 in the combination manifold. The
energized solenoid valves shift to allow a passage for
circuit oil flow to the barrel end of the left deck lift cylin-
der. Shifted S1 allows gear pump section oil flow to be
available for the lift/lower circuits. Shifted S2 and S4 al-
low an oil path to the barrel end of the right lift cylinder
to extend the lift cylinder and raise the right cutting deck.
Orifice OR2 (.063) controls the raising of the cutting
deck. Check orifice OR3 is bypassed when raising the
left cutting deck. Oil from the extending cylinder is di-
rected through S3 (de--energized), to the oil filter and
then to the traction charge circuit.
When the lift switch is released, the manifold solenoids
are de--energized and the lift cylinder and left cutting
deck are held in position.
1. Piston (traction) pump
Page 4 - - 19
2
1
Figure 10
rd
2. 3 gear pump section
Hydraulic System