6-33
Bucket dump
(3)
B1
A1
b1
a1
6
B1
A1
B2
A2
LS
a2
b2
b1
a1
Pst
T
Dump
Roll back
Up
Down
Floating
P
Bucket
Boom
Hydraulic circuit
6
75796WE57
When the pilot pressure is led to the port a1, the bucket spool moved to dump position.
Oil from the pump flows to the cylinder port A1, through the load holding valve and oil from the
cylinder flows into the tank passage through the cylinder port B1.
When the dumping speed of bucket is faster, the return oil from the large chamber of bucket
cylinder combines with the oil from the pump through regeneration check valve (6), and flows into
the small chamber of the cylinder. This prevents cylinder cavitation by the negative pressure when
the pump flow cannot match the bucket dump speed.
Summary of Contents for HL955
Page 557: ...7 6 MEMORANDUM MEMORANDUM ...