Raise Cutting Units - Toro Greensmaster TriFlex 3320/3420 Service Manual

Raise Cutting Units

The gear pump is directly coupled to the piston (traction)
pump. The gear pump supplies hydraulic flow for the
steering circuit (priority flow), for raising and lowering
the cutting units and for the traction charge circuit. The
gear pump takes its suction from the hydraulic reservoir.
Maximum circuit pressure of 1160 PSI (80 bar) is limited
by the relief valve located in the power steering valve.
The lift control manifold includes four (4) electrically op-
erated solenoid valves. Solenoid valve S1 causes circuit
flow to by--pass the lift cylinders when de--energized
and directs flow to the cylinders when energized. Direc-
tional solenoid valve S2 is used to direct oil flow to raise
the cutting units when de--energized and lower them
when energized. When energized, solenoid valve S3 al-
lows hydraulic flow to and from the front cutting unit lift
cylinders (#2 and #3) and prevents oil passage to and
from the lift cylinders when de--energized. When ener-
gized, solenoid valve S4 allows hydraulic flow to and
from the center cutting unit lift cylinder (#1) and prevents
oil passage to and from the lift cylinder when de--ener-
gized.
The console arm joystick is used to raise and lower the
cutting units. The joystick acts as an input to the TEC
controller to send electrical outputs to appropriate lift
control manifold solenoid coils in order to raise or lower
the cutting units.
While operating the machine during conditions of not
raising or lowering the cutting units (joystick in the neu-
tral (center) position), all of the lift manifold solenoid
valves (S1, S2, S3 and S4) are de--energized. Flow from
the gear pump is directed through the power steering
valve, de--energized solenoid valve S1 in the lift control
manifold, oil filter and to the traction charge circuit. Flow
in excess of charge circuit needs then returns to the gear
pump input.
Greensmaster 3320/3420
Raise Cutting Units
When the joystick is moved to the raise position, the Toro
Electronic Controller (TEC) energizes lift control man-
ifold solenoid valves S1, S3 and S4 for approximately
three (3) seconds. This time frame ensures that the cut-
ting units will be fully raised. The controller provides a
short delay in energizing solenoid valve S4 which delays
the raising of the center cutting unit (#1).
Energized lift manifold solenoids S1, S3 (front lift cylin-
ders) and S4 (center lift cylinder) direct circuit flow to-
ward the lift cylinders in the correct direction to raise the
cutting units. The front lift cylinders retract to raise the
cutting units while the center lift cylinder extends to raise
the cutting unit. Hydraulic pressure against the lift cylin-
der pistons moves their shafts causing the cutting units
to raise. At the same time, the lift cylinder pistons push
the hydraulic fluid out of the cylinders to de--energized
solenoid valve S2. Return flow continues to the oil filter
and then to the traction charge circuit.
A 0.037 orifice (OR1) controls raising speed for the cen-
ter cutting unit (#1). Flow to the front lift cylinders (cutting
units #2 and #3) bypasses the lift manifold orifices (OR2
and OR3) when the front cutting units are being raised.
When the lift control manifold solenoid valves are de--
energized by the TEC controller, spring action returns
the valves to their original position stopping lift cylinder
movement. The lift cylinder position is locked in place
since there is no complete circuit of flow to and from the
lift cylinders. Hydraulic flow by--passes the lift cylinders
and is routed to the oil filter and charge circuit.
NOTE: The raise function will not be allowed by the
TEC controller when the machine is in the backlap op-
eration with cutting reels engaged.
Page 5 - - 17 Hydraulic System