Operation Manual
BX25, RCK54(P)-23BX, RCK60B-23BX, LA240, BT601, WSM
BACKHOE
•
Bucket
(Roll-back)
,
(1
)
p
T
(2) (3)
(4) (5)
3TAAAAGNP009A
(1) Bucket Cylinder
(5) Spool
P:
Pump Port
A1
:
A1
Port
(2) Bucket Control Valve
(6) Inlet Section
T:
Tank Port
(From Bucket Cylinder)
(3) Bridge Passage
(7) Outlet Section
P.B.
:Power Beyond Port
B1
:
B1
Port
(4) Load Check Valve
(To
Bucket
Cylinder)
a:
Low
Pressure
b:
High Pressure
1.
When the dipperstick and bucket lever is moved to the left to set to the
"ROLL-BACK"
position, the spool (5)
of
the bucket control valve (2) moves to the right. which forms oil passage between bridge passage (3) and
B1
port,
and between
A1
port and T port.
2.
The pressure-fed oil from the P port opens the load check valve (4) and flows to
B1
port to extend the bucket
cylinder (1).
3.
Return oil from the bucket cylinder (1) returns to the transmission case through the A 1 port. low pressure passage
and T port.
9-M4