Lift Circuit (Up) - Toro Reelmaster 3100-D Service Manual

Lift Circuit (Up)

Raise Cutting Units
The gear pump (P2) is directly coupled to the hydrostat
through gear pump (P1). It supplies hydraulic pressure
(charge pressure) for raising and lowering the cutting
units, operating the sidewinder unit, and maintaining
100 to 150 PSI (6.9 to 10.0 bar) to the low pressure side
of the traction circuit. The pump takes its suction from
the hydraulic reservoir.
During conditions of not lifting or lowering cutting units,
flow from the gear pump is by−passed through the pow-
er steering valve, 2−spool valve, and hydraulic manifold
directly to the hydrostat and the charge relief valve. Flow
then returns to the hydraulic tank.
Reelmaster 3100−D
When the cutting units are to be raised, the 2−spool
valve is positioned by moving the cutting unit shift lever
to RAISE. Flow is directed to cap ends of the lift cylin-
ders. Hydraulic pressure against the cylinder pistons
moves their shafts causing the cutting units to raise. At
the same time, the pistons push the hydraulic fluid out
of the lift cylinders and back through the hydraulic man-
ifold to the hydrostat. When the cutting unit shift lever is
released, spring action returns the valve to its original
position and by−passes flow back to the hydrostat stop-
ping lift cylinder movement. The cylinder position is
locked in place, since there is no complete circuit of flow
to and from the lift cylinders.
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Hydraulic System