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31 - 7
Operation (cont’d)
Individual Operation
2. Service Spool Switch (Refer to Fig. 1, 2, 4).
When port 5Pa4 (5Pb4) is pressurised and the service spool
is switched (under neutral status), the neutral passage (A) is
closed and the oil is delivered from port 5P into the parallel
passage. The flow pushes up the load check valve (10) and
enters passage (D), the spool neck to cylinder port 5A4
(5B4).
The return oil from the cylinder port passes through 5B4
(5A4) past the spool neck and returns to the tank. An over
load relief valve can be installed to cylinder port 5A4 (5B4).
3. Bucket Spool Switch (Refer to Fig. 4).
When port 4Pa2 (4Pb2) is pressurised and the bucket spool
is selected, the neutral passage (a) is closed and the oil is
delivered from port 4P which pushes the load check valve
(11). The flow enters passage (d) from the parallel passage,
passes the spool neck to the cylinder port 4A2 (4B2).
The return oil from the cylinder port passes through 4B2
(4A2) past the spool neck and returns to the tank. It is also
possible to operate the bucket while operating left or right
travel by using the restrictor.
Section E
Hydraulics
9803/6020
Section E
31 - 7
Issue 1
Control Valve
289790
Fig. 4
A
C
B
D
A
Sevice
B
Bucket
C
To Boom 1 Section
D
To travel (Left) Section
Summary of Contents for JS70
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Page 189: ...Section E Section E Hydraulics 9803 6020 Issue 1 33 4 33 4 Control Valves Control Valve 291360...