Lift Circuit (Lower) - Toro Groundsmaster 7210 Service Manual

Lift Circuit (Lower)

Electrical Lift Control
Cutting Deck Float
Hydraulic System: Hydraulic Schematics
A single-section gear pump is directly coupled to the transmission which is driven
by the engine. This gear pump supplies hydraulic flow for raising and lowering the
cutting deck (or implement). The pump takes its suction from the hydraulic tank.
The circuit operation for lowering the cutting deck (or implement) is similar to
raising it. However, the hydraulic flow is used to retract the lift cylinder and this
action allows the cutting deck (or implement) to lower.
During the conditions of not raising or lowering the cutting deck (or implement),
flow from the gear pump is bypassed by the lift-control manifold directly to the oil
cooler and then to the transmission. The flow then returns to the hydraulic tank.
Note: The engine must be running to allow the cutting deck to be lowered. When
the bottom of the lift/lower switch is pressed (detent position), the deck will lower
fully and then enter the float position.
When the bottom of the lift/lower switch is pressed (detent position), the solenoid
valve A/S1 in the deck lift manifold is energized to cause the valve to shift. The
energized solenoid valve A/S1 allows a path for fluid flow from the cylinder head
of the cylinder. The weight of the cutting deck causes the lift cylinder to retract,
allowing the cutting deck to lower to the ground. An orifice in the manifold
controls the retracting speed of the lift cylinder while lowering the cutting deck.
The cutting deck float allows the fully lowered cutting deck to follow ground
surface contours. The deck lift manifold solenoid valve A/S1 stays energized for
the deck float when the deck is fully lowered. This energized solenoid provides
an oil passage to and from the lift cylinder to allow cylinder and cutting deck
movement while mowing.
Page 4–20 Groundsmaster 7210
16222SL Rev C