engage engine clutch (fig. 2-24).
b. Raise the open clamshell bucket from ground by
maintenance checks and services (para 3-6).
releasing digging brake pedal and hoist brake pedal (fig.
2-30. Operation of Dragline Fro nt End Attachment
a. Perform preventive maintenance checks and
and retract clutch lever and the hoist and propel clutch
services (para 3-6); start engine (para 2-10), and
lever.
engage engine clutch (fig. 2-24).
Note.
The above clutch levers are side-
b. Raise or lower boom (if necessary) to between
by-side, and may be controlled with one hand, if
40 and 45 angle (para 2-12c), the normal angle for
dragline operation.
desired. If the clamshell bucket starts to close in
c. Release digging brake pedal, allow bucket to
mid air, release pressure on crowd and retract
trip, then lower bucket to work area by releasing
clutch lever just enough to reopen bucket.
pressure on hoist brake pedal. When bucket touches
c. When bucket is high enough to clear
ground apply hoist brake pedal to prevent cable
obstructions, return crowd and retract and hoist and
overrunning.
propel clutch levers (fig. 2-24) to neutral and at the
d. To fill dragline bucket, pull crowd and retract
same time apply digging and hoist brake pedals to hold
clutch lever toward operator, slipping hoist brake as
open bucket in position.
required to allow bucket to level out when filled.
e. When bucket is loaded return crowd and retract
clutch lever to neutral and apply slight pressure to
e. Release digging brake pedal and hoist brake
digging brake pedal, then pull hoist and propel clutch
pedal and slowly lower open clamshell bucket to
lever toward operator. The slight pressure on digging
stockpile. The rate of bucket descent is controlled by
brake keeps bucket level and prevents it from dumping
pressure on hoist brake pedal. Allow closing line to run
its load.
free when lowering bucket.
f. When bucket is high enough to clear
Note.
If necessary to force bucket teeth
obstructions, swing to dumping area (para 2-12b), at the
into hard material, a long fast drop of bucket from
same time slipping digging brake to allow bucket to
tip of boom to stockpile will do the job.
swing out under boom point.
f. As soon as bucket enters material, apply digging
g. When bucket has reached the desired position
and hoist brake pedals to prevent cables overrunning.
for dumping, release all pressure on digging brake
g. Release digging brake pedal, and at the same
pedal.
time pull crowd and retract clutch lever toward operator
to close the bucket. To adjust digging depth, slack off
position and repeat above working cycle as often as
on hoist brake pedal as bucket closes and digs into
necessary.
material.
Note.
Working or digging area can be
h. When bucket is closed, pull the hoist clutch
enlarged beyond boom point by "casting" bucket.
lever toward operator, and at same time release hoist
i. To cast bucket beyond boom point, pull crowd
brake pedal. As bucket rises it may be necessary to
and retract clutch lever toward operator and bring
slack off on hoist clutch lever to avoid opening bucket in
bucket toward boom foot, as bucket is hoisted to half
mid air.
boom height. Swing boom toward work area (para 2-
i. Raise bucket high enough to clear obstructions;
release crowd and retract clutch lever and the hoist
position.
clutch lever, and at the same time apply pressure to
j. Release pressure on digging brake pedal and
digging brake and hoist brake pedals to hold bucket in
hoist brake pedal simultaneously. Apply pressure to
position.
both brake pedals to prevent cables from overrunning as
j. Swing the revolving frame to desired dumping
bucket reaches ground.
position (para 2-12b), then release digging brake pedal
k. Repeat steps c through g, i and j above as
to open bucket. Hold bucket with hoist brake pedal to
necessary.
prevent cable from unwinding.
l. When work for day is through, lower bucket to
k. Swing the open bucket back to loading point and
ground, and disengage engine clutch (fig. 2-24).
repeat steps b through j working cycle as often as
necessary.
maintenance checks and services (para 3-6).
l. When through with work for the day, lower
bucket to ground and disengage engine clutch (fig.
2-38
