Komatsu PC500LC-10R Shop Manual page 271

10 STRUCTURE AND FUNCTION
When the boom is in "NEUTRAL"
1.
When the control lever is returned to "NEUTRAL" in boom operation, the pressurized oil flowing into poppet
(5) through orifice (a) of poppet (5) is stopped by pilot piston (2).
2.
The holding pressure of the boom cylinder bottom 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 he boom cylinder bottom is shut off, and the oil pressure on the boom
cylinder side is hold.
PC500LC-10R
COMPONENT PARTS OF HYDRAULIC SYSTEM
A E P 2 1 6 3 0
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