DUMP TRUCK OPERATIONS

During dumping operations, the truck should be on level ground or inclined uphill with the front of the truck facing downward. When the truck is in position, release the lower latches of the tailgate with the hand lever at the front left corner of the body (fig. 7-37.) Then engage the control for the dump truck body. Hydraulic pressure will begin to hoist the dump truck body, and as the body rises, the load will slide backward under the open tailgate (fig. 7-38, view A). If the load piles up and blocks the tailgate (fig. 7-38, view B), place the truck in low gear and move it forward until there is more space to dump the remainder of the load.

If the load does not slide out easily, have someone dislodge it with a long-handled shovel, taking care not to stand in the immediate dumping area. When dumping a load of rocks or other large solids, see that the tailgate is latched at the bottom, but unfastened at the top, so that the tailgate can drop down and the load can drop, as shown in figure 7-39.

Not all dump trucks have tailgate wings. On those that do not, you have to drop the tailgate down and support it with chains. To spread a load over a large area,

Figure 7-39.-Tailgate rigged for dumping large material.

shift the truck into low gear and drive it slowly forward while dumping, as shown in figure 7-40.

The dump truck body can be held in any position by returning the control lever to the HOLD position. When dumping is completed, lower the body by returning the control lever to the LOWERING position. Then close the tailgate latches.

The load in a dump truck should be distributed evenly. Heaped loads to the front put more strain on the hoist. Loads to one side can damage the hinge pins, the dump bed, or bend the truck chassis. Remember: If your load should be distributed unevenly and dumped on uneven ground, you could find yourself in great difficulty, as shown in figure 7-41.

Figure 7-40.-Tailgate rigged for spreading operations.

Figure 7-41.-Hillside dumping hazard.

Figure 7-42.-Watch for overhead obstructions.

When regular rock dumps are not available, it may be necessary to haul large rocks in a dump body not designed for this purpose. The bed of the dump truck should then be lined with wooden planking so as not to damage the bed while the rock is being loaded. The tailgate should be latched again at the bottom but pushed out at the top, as shown in figure 7-39.

Before hauling asphalt, coat the inside of the bed with diesel fuel. The fuel prevents the asphalt from sticking to the dump bed. To control any rapid heat loss, cover the hot-mix with a tarpaulin that should be tied down securely to prevent flapping in the wind.

NOTE: Some states and countries require that all loose materials hauled in dump trucks must be covered to prevent spillage on roadways and breaking of vehicle windshields. Know the rules and regulations for the area you are to operate in.

Figure 7-43.-Avoid backing accidents; use a backing guide.

When performing dumping operations, be careful of overhead obstructions, as shown in figure 7-42. Ensure the dump bed is completely lowered before proceeding. When backing, use a backing guide to avoid a backing accident similar to the one shown in figure 7-43.