bolted around the hinge. The two hoist drum wire ropes
on the crane are rigged as the holding and closing lines
for controlling of the bucket. An example of a clamshell
rigging configuration is shown in figure 12-30.
The tag line winder (fig. 12-31) controls the tension
on the tag line that helps prevent the clamshell from
twisting during operations. Like the clamshell bucket,
the tag line winder will exchange with most makes or
models of cranes in the same-size range.
DRAGLINE
The dragline component (fig. 12-32) consists of a
dragline bucket and fairlead assembly. The wire rope
components of the dragline are the drag cable, the bucket
hoist, and the dump. Once a crane is rigged with a
dragline, the crane is referred to by the name of the
attachment,
When you are loading the bucket, the fairlead (fig.
12-33) guides the drag cable onto the hoist drum. The
hoist wire rope, which is reeved through the boom point
sheaves, raises and lowers the bucket.
WARNING
On some model of cranes, you must make
sure the fairlead is in a vertical position when
lowering the boom to avoid bending the cords
of the boom base.
Figure 12-31.—Tag line winder.
When changing attachments from hook block or
clamshell to dragline, check the operator’s manual for
the lengths and diameter size of wire rope required for
dragline operations. The pulling force of the dragline
Figure 12-30.-Clamshell rigging configuration.
12-18
