Komatsu Galeo PC138US-8 Shop Manual page 170

SEN02549-02
2. At boom lower load process
Function
When the head pressure (B) of the cylinder (1)
q
is higher than the bottom pressure (A) while
the boom is lowered and the boom is in the
load process, the check valve (3) will be
closed, and the circuits on the head side and
the bottom side will be interrupted.
Operation
When the boom is lowered and is in the load
q
process, the head side pressure (B) of the
boom cylinder (1) rises above the bottom side
pressure (A).
36
10 Structure, function and maintenance standard
At the time, the head side pressure (B) and the
q
spring (4) close the check valve (3), and the
circuits on the head side and the bottom side
are interrupted.
PC138US, USLC-8