jcb Robot 160 - Lift Arm Raise

Section E - Hydraulics
Operation Description
Loader Valve Operation
E - 23 E - 23
9803-9450-2
Fig 19. (X E-23) and Fig 20. (X E-24) show a manually
operated valve but the description also applies to servo
valves.
Lift Arm Raise
Fig 19.
Fig 19. (X E-23) shows lift arm raise selected. On servo
machines, when the joystick is moved servo oil is supplied
to the appropriate end of the tilt spool 8b which moves to
select the raise service. On manual valves the spool is
operated mechanically by movement of the control lever.
Also on manual machines the solenoid spool lock 8h is
energised to allow the spool to move.
The oil entering the valve block is diverted by the lift spool
8b to load hold check valve 8g which opens only when the
supply oil pressure rises above the service line pressure.
This prevents unwanted ram movement due to a possible
momentary fall in line pressure. The pressurised oil then
flows out of the valve block to operate the lift ram.
Oil returning from the opposite end of the lift ram enters the
valve block and flows past spool 8b but this time enters the
neutral circuit gallery before returning to tank.
8b
8
b
8g
8h