caution - Toro
caution - Toro
caution - Toro
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Lower Cutting Deck<br />
A four section gear pump is coupled to the piston (traction)<br />
pump. The third gear pump section supplies hydraulic<br />
flow to both the lift/lower control valve and the<br />
steering control valve. Hydraulic flow from this pump<br />
section is delivered to the steering and lift/lower circuits<br />
through a proportional flow divider that is located in the<br />
fan drive manifold. This pump section takes its suction<br />
from the hydraulic reservoir.<br />
When the cutting deck is in a stationary position, flow<br />
from the gear pump is by--passed through the lift/lower<br />
control valve, counterbalance manifold, oil filter and<br />
traction charge circuit.<br />
To lower the cutting deck, the center lift lever on the lift/<br />
lower control valve is pushed to allow valve shift in the<br />
lift/lower control. This valve change allows a passage for<br />
oil flow from the rod end of the front deck lift cylinders.<br />
The weight of the cutting deck causes the lift cylinders<br />
to extend, and lower the cutting deck. Oil from the rod<br />
end of the cylinders is allowed to return to the traction<br />
charge circuit. When the lift lever is released, the lift cylinders<br />
and cutting deck is held in position.<br />
The drop speed of the front cutting deck is regulated by<br />
an adjustable flow control valve that is located in the hydraulic<br />
lines between the lift/lower control valve and the<br />
deck lift cylinders.<br />
To lower a wing deck, the appropriate lift lever on the lift/<br />
lower control valve is pushed to allow valve shift in the<br />
lift/lower control valve. This valve change causes a<br />
valve shift in the counterbalance manifold and oil flow to<br />
the barrel end of the lift cylinder. Higher hydraulic pressure<br />
against the barrel end of the cylinder causes the<br />
cylinder shaft to extend, and lower the wing deck. Oil<br />
from the piston end of the cylinder returns to the traction<br />
charge circuit. When the lift lever is released, the lift cylinder<br />
and wing deck is held in position.<br />
An adjustable counterbalance valve (CB) in the counterbalance<br />
manifold maintains back pressure on the deck<br />
lift cylinders to allow some of the cutting deck weight to<br />
be transferred to the traction unit to improve traction. A<br />
relief valve located in the lift/lower control valve limits lift/<br />
lower circuit pressure to 1500 PSI (103 bar). Excess circuit<br />
flow is routed to the oil filter and then to the traction<br />
charge circuit.<br />
Hydraulic<br />
System<br />
Groundsmaster 4100--D<br />
Page 4 - 15<br />
Hydraulic System