Hoist Circuit
The hoist circuit controls boom raise and lower. Pilot fluid from the left hand joy stick (controller) is directed to the
selected end cap of the main control valve shifting the spool. Whenever the spool shifts, fluid is directed to the
two hoist cylinders, raising or lowering the boom.
FIGURE 60
HOIST CIRCUIT
Hoist Cylinders
There are two (2) cylinders used in the GRADALL Hoist circuit. They are attached to the main frame and boom
cradle. Whenever the cylinder rods retract, the boom lowers. Whenever the cylinder rods extend the boom raises.
Main pump fluid is directed to both cylinders simultaneously through large hydraulic fluid tubes located at the
rear of the cylinders. These tubes are fed from port A or B of the control valve. Return fluid flows through the
opposite unpressurized port.
XV. Hoist Circuit
Hoist Up
Hoist Cylinders
Hoist Down
Hoist
C.V.
Main Pump
Joystic
k
Pilot Pressure
Tank
Form No. 29703
52
Fluid Path Simplified for Clarity
NOTE!
P - Pilot Pressure
T - Return Fluid To Tank
A/B - Main Control Valve Ports
Содержание XL4000
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Страница 305: ...GRADALL h y d r a u l i c e x c a v a t o r s XL 4000 5000 CENTER PIN REBUILD Form No 20026 Part No 2460 4164 ...