Figure 7-38.—Dumping the load.reading and understanding the operator’s manual for themodel of dump truck you are assigned to operate. Thissection covers the basic characteristics and operationsof dump trucks.CHARACTERISTICSA typical dump truck is equipped with a dump bodythat is hinged to the rear of a subframe which is mounteddirectly on the truck chassis. Dump bodies range instructural strength and size to support differentoperations. That is why it is important that the operatorknows the design and capacity of the dump truckassigned to operate. You do not want to haul quarry rockin a dump body designed to haul and heat asphalt. Thequarry rock can damage the dump body and render ituseless for asphalt operations. The components of adump truck body are shown in figure 7-36.A hydraulic hoist assembly is used to raise andlower the dump truck body. The hydraulic pump isdriven by a propeller shaft connected to the powertakeoff (PTO). A variety of ways are used to engage thePTO on dump trucks used in the NCF; therefore, consultthe operator’s manual for specific instructions on howto engage the PTO and hoist assembly.DUMP TRUCK OPERATIONSDuring dumping operations, the truck should be onlevel ground or inclined uphill with the front of the truckfacing downward. When the truck is in position, releasethe lower latches of the tailgate with the hand lever atthe front left corner of the body (fig. 7-37.) Then engagethe control for the dump truck body. Hydraulic pressurewill begin to hoist the dump truck body, and as the bodyrises, the load will slide backward under the opentailgate (fig. 7-38, view A). If the load piles up andblocks the tailgate (fig. 7-38, view B), place the truck inlow gear and move it forward until there is more spaceto dump the remainder of the load.If the load does not slide out easily, have someonedislodge it with a long-handled shovel, taking care notto stand in the immediate dumping area. When dumpinga load of rocks or other large solids, see that the tailgateis latched at the bottom, but unfastened at the top, so thatthe tailgate can drop down and the load can drop, asshown in figure 7-39.Not all dump trucks have tailgate wings. On thosethat do not, you have to drop the tailgate down andsupport it with chains. To spread a load over a large area,Figure 7-39.—Tailgate rigged for dumping large material.7-31
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business