jcb JS300 Service Manual page 704

Section E - Hydraulics
Hydraulic System
Hydraulic Operation and Schematics
Bucket Close
K Fig 11. ( T
For schematic, E-44).
Servo pressure from the RH hand controller 48 is sent from
port 3 via ports A7 and B7 of the shuttle valve 46 to port
Pb7 of the main control valve 14 and moves the bucket
spool into the bucket close position and selects the upper
pressure switch.
Flow from pump A2 is available at the bucket spool via the
parallel working gallery and boom over bucket priority
valve BBV.
Flow is diverted to port B7 of the main control valve to the
bucket ram 13.
Returning oil from the bucket ram enters the main control
valve at port A7and is diverted to tank by the bucket spool.
A regeneration valve is fitted in the bucket spool
K Fig 11. ( T
E-44). When returning oil from the bucket
ram enters the spool it crosses a restrictor which causes
back pressure. If the pressure in the return line is greater
than that of the feed line, the valve will open allowing return
oil to be regenerated into the feed line.
E-43 9813/5100-1 E-43