31 - 12
Operation (cont’d)
2. Crowd 2 Speed Confluence (Refer to Fig. 1, 2, 10,).
When the pilot port 5Pa2 is pressurised and arm 1 spool is
selected (Fig. 10), 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
and flows to the cylinder port 5A2.
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
5A2.
The restriction (31) is designed to give priority when
operating swing.
When the arm 1 spool is selected, port PLc2 is pressurised,
the spool (23) of the anti-drift valve is switched. The pressure
in the spring chamber (24) is reduced and the poppet (22) is
opened, the return oil from port 5B2 flows from the arm 1
spool neck to the tank.
When the arm 1 spool is selected, port 4Pa4 is pressurised
and the arm 2 spool is switched, the neutral passage (a) is
cut off. The oil delivered from port 4P flows through neutral
passage (a), to passage (3) and pushes up the load check
valve (20) and flows through passage (G) through the arm 1
spool neck and converges at port 4B3.
Part of the flow from port 4P pushes up the tandem check
valve (21) and converges in passage (4) at port 5A2.
Section E
Hydraulics
9803/6020
Section E
31 -
Issue 1
Control Valve
Fig. 10
289830b
A
Arm 1
B
Arm 2
C
Crowd
A
B
C
Summary of Contents for JS70
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