7. The drag cable can be reversed end for end toprolong the life of the wire rope, reduce early wire ropereplacement, and keep wire rope cost down.Remember, the drag cable should not be lubricated.8. When lowering the dragline bucket into the areato be worked, release the drag brake to tip the cuttingedge down and then release the hoist brake. You do nothave to drop the bucket to force the teeth into thematerial. The bucket is filled as it is dragged toward thecrane by engaging the drag control lever. The cuttingdepth is controlled by releasing tension from the hoistbrake. The dragline is NOT a positive digging tool.9. The dragline cycle is filling the bucket, liftingthe bucket, swinging the loaded bucket, and dumpingthe load.10. Since the dragline is not a rigid attachment, itwill not dump materials as accurately as do otherexcavators. When a load is dumped into a haul unit orhopper, you need more time to position the bucketbefore dumping it.NOTE: When you are dumping into a haul unit,NEVER load over the cab. Additionally, make sure theoperator is out of the cab and clear of the dragline orclamshell bucket.11. The boom angle for dragline operations shouldnormally be from 25 to 35 degrees. However, check thecrane load chart to ensure this low boom angle does notexceed the capacity of the crane. At this relatively lowboom angle, you must be careful when excavating anddumping wet, sticky materials, because the chance oftipping the crane is increased because the material tendsto hang in the bucket.Dragline EmploymentThe dragline can be used in dredging where thematerial handled is wet and sticky. It can dig trenches,strip overburden, clean and dig road side ditches, andslope embankments.When the dragline is handlingmud, it is the most practical attachment. Its reachenables it to handle a wide area of excavation whilesitting in one position, and the sliding action of thebucket eliminates trouble with suction.Other uses of the dragline include the following:1. In-line approach.When excavating a trenchwith the dragline, ensure the dragline and carrier unit arecentered on the excavation (fig. 12-48). The draglinecuts or digs to the front and dumps on either side of theexcavation. The crane moves away from the face as thework progresses.2. Parallel approach. The dragline can slope anembankment better by working it from the bottom to thetop. The crane is positioned on the top with the carrierparallel to the working face, so it can move the fulllength of the job without excessive turning.3. Drainage. A dragline is ideal if earthworkmaterials have to be removed from a trench, canal,gravel pit, and so forth, containing water. Plan the workto begin at the lowest grade point, so drainage will beprovided as the dragline progresses towards higherlevels.NOTE: Digging underwater or in wet materialsincrease the weight of the materials and frequentlyprevent carrying heaped bucket loads.Ditching the excavation through swamps or softterrain is common. Under these conditions theexcavated material is normally cast onto a levee or spoilsbank.4. Loading haul units. When the job requiresexcavated material to be loaded into hauling units, theexcavation should be opened up so loaded haulingequipment can travel on high, dry ground or on bettergrades. The spotting of trucks and dragline should beplanned for minimum boom swing with the truck bedunder the boom point and the long axis of the bedparallel with the long axis of the boom or at right anglesto the boom. More spillage is to be expected from adragline than from a front-end loader.Efficient Dragline OperationOther uses of the dragline operation include thefollowing:1. Although the dragline bucket can be readily castbeyond the length of the boom, the machine should bepositioned to eliminate casting.2. Use heavy timber mats for work on soft ground.The mats should be kept level and clean.3. When setting up for a dragline operation, youshould have access for maintenance, operatingpersonnel, and hauling equipment.4. Excavate the working area in layers, not intrenches, and keep the slope upward toward thecrane.5. Do not drag the bucket in so close to the cranethat it builds piles and ridges of material in front of thecrane.12-35
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