Komatsu Galeo PC138US-8 Shop Manual page 178

SEN02549-02
2. At simultaneous operation of swing + boom RAISE
Operation
At the simultaneous operation of swing + boom
q
RAISE, the signal pressure of the PPC circuit
is led to the pilot port (BP).
When this pilot pressure (BP) is applied to the
q
piston (2) and reaches a pressure that is stron-
ger than the spring (3), the piston (2) will be
pushed to the left side, the valve (1) will close
and the pump discharge pressure (PP) will not
come to flow to the pressure reducing valve (4)
of the swing valve.
Then, the swing pressure does not cause LS
q
pressure (PLS), but the LS pressure (PLS)
caused by the boom RAISE pressure is led to
the pump LS valve, and the pump delivery is
controlled with the boom RAISE LS pressure.
The pilot pressure (BP) depends on the control
q
lever stroke.
44
10 Structure, function and maintenance standard
PC138US, USLC-8