National Crane 600H, Руководство по обслуживанию

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HYDRAULIC SYSTEM SERVICE MANUAL 600H
2-10
08-19-2022 Control # 092-13
CONTROL VALVE RELIEF ADJUSTMENT
The control valves supplied on this crane are equipped with
adjustable relief valves. After some time of use, it may be
necessary to make some adjustment in pressure because of
spring weakening, etc. The relief valves are adjustable only
through a specific pressure range.
Both the inlet and mid-inlet of the main control valve and inlet
of the hoist valve have screw adjustable main relief valves.
Turning the relief in increases pressure relief setting; turning
the relief out decreases pressure relief setting.
The turn circuit pressure can be checked by plugging a port
on the turn motor with a pressure gage. The pressure on the
main control valve stack should be checked by booming the
lift cylinder down against the end of the cylinder stroke. The
hoist circuit pressure can be checked by plugging a port on
the hoist motor with a pressure gage.
Some valve sections include work port reliefs. The work port
reliefs are shim adjustable. Adjustment is made by adding or
taking out shims. Adding a 0.010 shim will increase pressure
100 psi (0.68 MPa). See “Specifications” section for correct
pressure settings.
Never set pressure above recommendations.
Linkage End
of Spool
Spool Action
Bonnets
Inlet Cover
Outlet
Inlet
Main Relief
Work
Ports
Outlet
Cover
NOTE: Remove cap
to adjust main relief.
Spool Seal
Backup Washers
Retainer Plate
Crane Valve Cover
10 ft-lb (13.5 N.M)
Hoist Valve Cover
5 ft-lb (6.7 N.M)
Bonnets
Assembly
Crane Valve Cover
10 ft-lb (13.5 N.M)
Hoist Valve Cover
5 ft-lb (6.7.8 N.M)
FIGURE 2-2
WARNING
If the machine does not perform properly at these
pressures, the problem is not the relief valve and no
attempt should be made to readjust the setting. If the relief
valves are set to higher pressures than those listed
above, the warranty on the machine is void. Also the
machine could operate in a manner such as to endanger
personnel safety.
REFERENCE ONLY