Komatsu PC500LC-10R Shop Manual page 275

10 STRUCTURE AND FUNCTION
When the arm is in "NEUTRAL"
1.
When the control lever is returned to "NEUTRAL" in arm operation, the pressurized oil flowing through ori-
fice (a) of poppet (5) into poppet (5) is stopped by pilot piston (2).
2.
The holding pressure of the arm cylinder head acts rightward on the left side of area (S) of the ring formed
by the difference between outside diameter (d1) of poppet (5) and seat diameter (d2).
3.
The combined force of the force acting rightward on area (S) and the reaction force of spring (4) moves
poppet (5) to the right.
4.
The circuit from the control valve to the arm cylinder head is shut off, and the oil pressure on the arm cylin-
der head side is hold.
PC500LC-10R
COMPONENT PARTS OF HYDRAULIC SYSTEM
A E P 2 1 6 0 8
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