Komatsu D155A-6 Operation & Maintenance Manual page 202

OPERATION OPERATION
2. Operate the ripper lever to the TILT position and carry out
ripping and digging.
3. If there are boulders which are impossible to break or dig up
with the tilt operation, move forward slightly and tilt the shank
back, then operate the tilt again and dig up the boulder.
4. Even when the operation in Step 3 is repeated, if it is
impossible to break or dig up the boulder, drive back about 10
cm, raise the shank, avoid the rock or boulder that cannot be
ripped, then drive forward and start ripping again.
PRECAUTIONS WHEN RIPPING
For the digging angle when ripping, set so that the top of the
shank is perpendicular, then lower the ripper (c).
OPERATION OPERATION
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