33 - 8
Boom Lower (BM) Operation
When pilot pressure is applied by operating the right hand
joystick controller, spool B moves to the right, closing off the
neutral gallery and allowing oil from pump P2 to enter the
cylinder port. Oil below check valve M flows through ports G
and H to open check valve K and pass through port L to the
gallery J. Pressure in gallery J depresses the check valve M
allowing oil to flow from the ram to the exhaust gallery.
Without pilot pressure, the centre bypass valve and the logic
check valve allow the oil to enter the low pressure gallery N
and return to tank.
Section E Hydraulics
9803/6410
Section E
33 - 8
Issue 1
Control Valve
JS01750