Loader Operation

_{A front-end loader} can dig excavations, such as building foundations and other belowground areas, if the material to be excavated is not too hard. Belowground operations require construction of a ramp into the excavation to bring the material out (fig. 9-17). The slope of the ramp depends on the type of loader operated; for example, a crawler-mounted loader may dig a more abrupt approach to the excavation.

When loading from a bank or stockpile, use the "V" method shown in figure 9-18 or the step-loading method shown in figure 9-19. Position the dump truck at about a 30-degree to a 45-degree angle from the stockpile. Additionally, when possible, load the dump truck downwind to prevent dirt and dust from blowing back into your face. Keep the truck close to the work area to minimize loader travel, and keep the work area clean and level.

The bucket is loaded by moving the loader forward with the bucket at the desired digging level and with the engine at full-governed speed. As the bucket penetrates the material, raise the bucket slightly. When the material fills to the top of the spill board, roll the bucket all the way back (fig. 9-20). The rollback position is maintained to prevent spillage while backing away.

When transporting material, raise the lift arm to give the bucket the same ground clearance as provided by the loader axle.

^{Figure 9-20.-Bucket-loading technique}

Keep the travel speed reasonable for safe operation. Upon reaching the truck, raise the bucket high enough to clear the truck body. Reduce forward speed and dump the load in the center of the dump bed, as

Figure 9-21.-Loading the dump truck.

Figure 9-22.-Bucket positioned for filling from a bank.

shown in figure 9-21. Shake the bucket to loosen dirt from within. After the load is dumped, back away, lower the bucket to the carrying position, and return to the digging area.

CAUTION

A loaded bucket must never be transported in the fully raised position.

NOTE: Dump trucks should be loaded from the driver's side whenever possible. When the truck is being loaded, be sure the driver either stays in the cab (on cab-protected trucks) or away from the truck and loader.

When loading from a bank, keep the cutting edge flat, as shown in figure 9-22. Tilting the bucket back too far forces the flat of the cutting edge against the bank, preventing the bucket from digging. This maneuver is nonproductive and causes waste of power, time, and possible damage to the bucket cylinders and linkage.

When stockpiling material, move each load only once and keep the travel distance short. When possible,

Figure 9-23.-Bucket positioned for clearing rocks or othersolid objects.

locate stockpiles as close to the jobsite as possible without hindering other work on the jobsite.

When clearing a rocky area, remove the small and loose rocks first. Large rocks and other solid objects can then be loosened and moved easier.

Figure 9-24.-Loading large rocks.

Figure 9-25.-Bucket positioned for back dragging nonsolidmaterials.

When loosening large rocks or other solid objects, you can get greater force and penetration by digging under the rock with the bucket, as shown in figure 9-23. Lifting the rock with the bucket while pushing increases traction and reduces track or wheel spinning. When loading large rocks into dump trucks, place a load of dirt or sand into the dump bed. This material acts as a cushioning material and helps protect the dump bed from damage. Then load the large rocks into the center of the dump bed from the lowest possible height (fig. 9-24).

Figure 9-26.-Bucket clamshell positioned for spreadingmaterial.

Figure 9-27.-Bucket clamshell positioned for loading trees.

NOTE: When you have extended tasking to haul large rocks or riprap, you should have the dump beds lined with wooden planking. This will save time loading sand or dirt and also protect the bed.

When finishing by back dragging in nonsolid materials, position the bucket, as shown in figure 9-25, views A or B.

NOTE: Back dragging abrasive materials causes premature wear to the bucket.

By placing the bucket in the scraper position and opening the clamshell slightly, you can spread material on the run. The amount of spread can be controlled by the size of the opening of the clamshell, as shown in figure 9-26.

When transporting trees or other large objects, always balance the load, as shown in figure 9-27.

Figure 9-28.-Removing buried objects using the clamshell byrolling back the bucket.

Figure 9-29.-Breaking off an object using the clamshell byback dragging.

Balance the load when picking it up to prevent twisting the boom assembly and linkage. When dumping awkward loads, dump slowly to reduce the shock of weight transfer to the rear axle when the bucket is emptied.