Komatsu Galeo PC800-8 Shop Manual page 265

10 Structure, function and maintenance standard
Operation
• This function acts to change the set pressure of the safety valve at the boom cylinder end of the R.H. 4-spool
control valve boom Lo in 2 ways: to low pressure (14.7 MPa {150 kg/cm
kg/cm }.
2
Machine push-
Mode
up switch
Boom pushing
force
(low mode)
Boom pushing
force
(high mode)
a Machine push-up solenoid valve
For details of the structure and function, see Solenoid valve.
a Boom safety valve
For details of the structure and function, see R.H. 4-spool control valve.
PC800, 850-8
Machine push-
Safety valve set
up solenoid
pressure
valve
14.7 MPa
Energized
{150 kg/cm
33.3 MPa
De-energized
{340 kg/cm
}) and high pressure (33.3 MPa {340
2
Effect
By reducing the boom pushing force, it is
made easier for the boom to escape auto-
matically in the RAISE direction and to
2 } reduce the number of times that the boom
is operated. At the same time it also
makes the digging operation smoother.
By increasing the thrust force for boom
LOWER, the ease of operation is
improved for excavation, digging square
2 }
holes, carrying out twist turns, or escap-
ing from soft ground.
SEN00386-03
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