Toro Reelmaster 5010- H - Lift Circuit: Raise Cutting Units

Reelmaster 5010- H Hydraulic SystemPage 4 - 15
Lift Circuit: Raise Cutting Units
A two section gear pump is coupled to the piston (trac-
tion) pump. Gear pump section (P1) supplies hydraulic
flow to the lift control manifold and ultimately for the lift
cylinders. The hydraulic reservoir provides fluid for the
gear pump through the suction hose. Lift circuit pressure
is limited to 2000 PSI (138 bar) by a solenoid relief valve
(SVRV) located in the lift control manifold.
The lift control manifold includes four (4) electrically op-
erated solenoid valves. Valve (SVRV) is used to direct
gear pump flow to the lift cylinders when energized or
bypass pump flow back to the reservoir when de- ener-
gized. Valve (SV2) is used to direct oil flow to retract the
lift cylinders when energized or extend them when de-
energized. Valve (SV1) allows hydraulic flow to the front
lift cylinders when energized. Valve (SV3) allows hy-
draulic flow to the rear lift cylinders when energized.
Lift circuit pressure can be monitored at lift c ontrol man-
ifold port G4.
The TEC controller uses inputs from various machine
switches to determine when lift manifold solenoid valves
(SV1, SV2, SV3 and SVRV) are to b e energized. The
TEC also provides a partial raise position of the front out-
side cutting units.
During conditions of not raising or lowering the cutting
units (joystick in the neutral (center) position), all four (4)
lift manifold solenoid valves (SV1, SV2, SV3 and SVRV)
are de- energized. Hydraulic flow from gear pump sec-
tion (P1) by- passes the lift cylinders to the oil cooler and
then to the hydraulic reservoir.
Raise Cutting Units (Fig. 13)
When the joystick is moved to the raise position, sole-
noid valve (SVRV) energizes along with solenoid valves
(SV1), (SV2) and (SV3). The energized solenoid valves
direct gear pump section P4 oil flow to the rod end of the
lift cylinders. Hydraulic pressure against the rod side of
the c ylinders causes the shafts to retract, a nd raises the
cutting units. Fixed orifices in the lift control m anifold
(C1L, C4L, C5L and C23L) control the lifting speed by
providing a restriction for the return flow from the lift cyl-
inders.
When the joystick is returned to the neutral (center)
position, the lift manifold solenoid valves are de- ener-
gized and the lift cylinders (and cutting units) are held in
the raised position. Piloted check valves in the lift control
manifold (CV1, CV4, CV5 and CV23) prevent the lift cyl-
inders (and cutting units) from dropping after they have
been raised.
Hydraulic
System