31 - 11
Operation (cont’d)
Dipper Spool Selection
1. Dump 2 Speed Confluence (Refer to Fig. 1, 2, 9).
When the pilot port 5Pb2 is pressurised and the arm 1 spool
is selected and the neutral passage (A) is closed, oil
delivered from port 5P pushes up the tandem check valve
(19) and flows through the passage (G) and the spool neck.
The flow pushes open the anti-drift valve poppet (22) and
flows to the cylinder port 5B2.
Part of the oil delivered by port 5P flows from 5-spool
parallel passage (B) to the restriction (31), pushes open the
load check valve (18) and converges in passage (G) to port
5B2.
When the arm 1 spool is selected, the arm 2 spool is
pressurised through passage (17) and the neutral passage
(a) is closed, oil delivered from port 4P passes through the
neutral passage (a) to passage (3) pushes up the check
valve (20) and converges to port 5B2.
Part of the oil delivered by port 4P pushes up the tandem
check valve (21) passes through passage (4) to the arm 1
spool neck and converges at port 5B2.
The return oil from cylinder port 5A2 flows through the spool
neck and is released to the tank passage.
Section E
Hydraulics
9803/6020
Section E
31 -
Issue 1
Control Valve
Fig. 9
289830a
A
B
C
A
Arm 1
B
Arm 2
C
Dump
Summary of Contents for JS70
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