Digging Methods - Komatsu WB140-2N Operation & Maintenance Manual

OPERATION

DIGGING METHODS

Be careful when excavating a deep trench, the machine is capable of excavating the surface underneath
the outriggers thus causing the machine to fall into the excavated trench. Always be aware of this.
• To start, position the bucket at a slight penetration angle into the soil shown below in the first illustration on the left.
• Begin retracting the arm while raising the boom simultaneously. Take care not to lift the machine when performing this
part of the operation. Keeping your bucket leading edge parallel with the surface being excavated.
• Once you are at the end of your stroke or the bucket is full, curl the bucket keeping it level with the ground. Raise the
boom and lift the arm and bucket out of the excavated site.
• Once you are at a clear height, swing the boom to the right or left depending on your deposit point. Lower the boom and
dump the full bucket extending or retracting the arm if needed.
• When excavating a trench at a depth shown in the illustration on the right, simultaneously retract the arm, raise the boom
and curl the bucket keeping the leading edge of the bucket at a slight penetration angle into the soil but parallel with the
surface being excavated.
CORRECT
The bucket works best with its flat surface or cutting
edge tipped down slightly but parallel to the ground.
INCORRECT
The bucket is thrust downward reducing
the breakout force and filling the bucket too quickly.
INCORRECT
The bucket is pushed upward, lifting the machine
thus not filling the bucket.
2-40
Sequence 1-2-3, shows the proper way to
excavate a trench. Always keep the cutting edge
of the bucket tipped down slightly but parallel
with the surface being excavated.
WB140-2N, WB150-2N