To Next Page

To Previous Page

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 Arm 1

B Arm 2

C Dump

jcb JS70 Service Manual

Other manuals for jcb JS70