Komatsu Galeo PC138US-8 Shop Manual page 172

SEN02549-02
2. At arm in process
A : Head circuit
B : Bottom circuit
PP : Pump circuit
Function
When the bottom pressure (B) of the cylinder
q
(1) rises above the head pressure (A) and the
arm enters the digging process, the check
valve (3) will be closed and the circuits on the
head side and the bottom side will be inter-
rupted.
Operation
When the arm is in the digging process, the
q
bottom side pressure (B) of the arm cylinder
(1) will rise, close the check valve (3) and inter-
rupt the circuits on the head side and the bot-
tom side.
38
10 Structure, function and maintenance standard
1. Arm cylinder
2. Arm spool
3. Check valve
PC138US, USLC-8