6-7
WHEN THE RCV LEVER IS IN THE FLOAT POSITION
When the RCV lever (4, boom) is pushed further forward from the lower position, the pilot pressure
reaches to 13~15bar, then the boom spool is moved to floating position.
The work ports (A2), (B2) and the small chamber and the large chamber are connected to the
return passage, so the boom will be lowered due to it's own weight.
In this condition, when the bucket is in contact with the ground, it can be move up and down in
accordance with the shape of the ground.
·
·
·
1
T
A1
P1
X1
X2
X3
S1
B2
L3
L4
B1
L1
L2
S1
S2
X1
X2
PS
Aux
Bucket
Boom
Joystick
4
1
EHCU
EH20
EH19
EH22
EH21
P
T
6(4)
3(2)
5(3)
2(1)
( ) : 2 Spool
EH18
EH17
To MCV
a3 b3 a1 b1
a2
b2
Return line
Fan & brake pump
Steering system
Return line
Steering valve
(EHPS) EF port
Steering valve
(EHPS) LS port
3
LH
B1
A1
B2
A2
LS
a2
b2
b1
a1
Pst
B3
A3
b3
a3
T
P
PS
PS
RH
Dump
Roll back
Up
Floating
Bucket
Boom
Aux
Down
23
22
25
24
12
11
26
28
28
29
6
5
4
4'
40
14
13
29
29
Control unit
(Electro-Hydraulic & Joysick steering)
3)
757F6WE05
Summary of Contents for HL955
Page 557: ...7 6 MEMORANDUM MEMORANDUM ...
