Spray Boom Lift Circuit - Toro Multi Pro 5800 Service Manual

Spray Boom Lift Circuit

A two (2) section gear pump is coupled to the piston
(traction) pump. The front gear pump section (closest to
the piston pump) supplies hydraulic flow to the spray
pump drive circuit. The rear gear pump section supplies
hydraulic flow to both the steering and spray boom lift/
lower circuits. Hydraulic pump flow from the rear pump
section is routed to the steering control valve first so the
steering circuit has priority. The gear pump takes its suc-
tion from the hydraulic reservoir. Steering and boom lift/
lower circuit pressure is limited to 1015 PSI (69 bar) by
a relief valve located in the gear pump.
Spray boom lift circuit hydraulic flow can be monitored
at the outlet of the rear gear pump section. Circuit pres-
sure can be measured at a diagnostic fitting in port G on
the boom lift control manifold.
The boom lift control manifold includes three (3) electri-
cally operated valves. Solenoid valve (S1) is used to di-
rect oil flow toward the boom lift cylinders when
energized or allow circuit flow to bypass the cylinders
when de--energized. Solenoid valve (S2) controls hy-
draulic flow to raise or lower the left side boom lift cylin-
der. Solenoid valve (S3) controls hydraulic flow to raise
or lower the right side boom lift cylinder.
While operating the machine during conditions of not
raising or lowering a spray boom (boom lift switches in
the neutral (center) position), all of the boom lift control
manifold valves (S1, S2 and S3) are de--energized. The
de--energized valve (S1) allows hydraulic flow to return
to tank through the boom lift control manifold. Flow re-
turns to the oil filter and then to the hydraulic reservoir.
Raise Spray Boom (Fig. 14)
When a boom lift switch is depressed to the raise posi-
tion, manifold solenoid valves (S1) and the raise coil for
either (S2) (LH cylinder) or (S3) (RH cylinder) are ener-
gized. The energized (S1) directs oil flow toward the
boom lift cylinders. The other energized valve (S2 or S3)
shifts to allow pump flow to be directed toward the rod
end of the lift cylinder through a manifold check valve
and orifice that controls lift speed. The lift cylinder re-
tracts to raise the boom section.
Displaced oil from the barrel end of the lift cylinder re-
turns to the manifold, bypasses an orifice, is routed
through the shifted valve (S2 or S3), exits the control
manifold through port T, is routed to the oil filter and then
returns to the hydraulic reservoir.
Multi Pro 5800
When the lift switch is returned to the neutral (center)
position, the manifold solenoid valves are both de--ener-
gized. The de--energized valve (S1) allows hydraulic
flow to return to tank through the manifold. The boom lift
cylinder is held in the raised position by de--energized
valve (S2) (LH cylinder) or (S3) (RH cylinder).
Lower Spray Boom (Fig. 14)
When a boom lift switch is depressed to the lower posi-
tion, manifold solenoid valves (S1) and the lower coil for
either (S2) (LH cylinder) or (S3) (RH cylinder) are ener-
gized. The energized (S1) directs oil flow toward the
boom lift cylinders. The other energized valve (S2 or S3)
shifts to allow pump flow to be directed toward the barrel
end of the lift cylinder through an orifice that controls
lowering speed. The lift cylinder extends to lower the
boom section.
As circuit pressure increases, a manifold sensing line
shifts the check valve (CV1 for the LH cylinder or CV2
for the RH cylinder) to allow a return path for oil from the
rod end of the lift cylinder. Displaced oil from the rod end
of the lift cylinder returns to the manifold, bypasses an
orifice, flows through the shifted check valve, is routed
through the shifted valve (S2 or S3), exits the control
manifold through port T, is routed to the oil filter and then
returns to the hydraulic reservoir.
When the lift switch is returned to the neutral (center)
position, the manifold solenoid valves are both de--ener-
gized. The de--energized valve (S1) allows hydraulic
flow to return to tank through the manifold. The boom lift
cylinder is held in the raised position by de--energized
valve (S2) (LH cylinder) or (S3) (RH cylinder).
LH BOOM
CYLINDER
RETRACT TO
C2 C1
.036 .036
CV1
S2
G P
Page 4 - - 19
RH BOOM
CYLINDER
BOOM CYLINDERS
STATIONARY
RAISE
C3 C4
.036 .036
CV2
S3
(SOLENOIDS
S1, S2 AND S3 ALL
DE- -ENERGIZED)
S1
BOOM LIFT
CONTROL
MANIFOLD
T
Figure 15
Hydraulic System