Most of you will have no interest whatsoever in this article, but a few will. Others already know all this. This is for those few who don’t know, but are curious.
Obviously, a dump truck’s job is not to load itself, that’s the job of other machinery. A dump truck’s job is to haul a load and unload it. For that task, it has a bed that can be raised to a steep angle, and a tailgate that can be opened either partially or completely. The average tailgate is hinged at the top. I didn’t show that, since the owner’s name is painted on this one and I choose to protect his privacy. The finger-like projection that you see at the lower left-hand corner is one of the latches. It has a mate on the other lower corner which doesn’t show well from the angle of the photo. The bed tilt and the latch are controlled from the driver’s seat.
Click image to enlarge.
When arriving at the dump site, the tailgate is unlatched and the bed is raised, thus allowing the load to slide out the back of the bed. A variation occurs when the customer wants the load spread, such as stone on a driveway. At those times, both the rise of the bed and the opening of the tailgate are both controlled, and the truck moves along the dump route, rather than sitting in one spot. Some refer to this as “tailgating” the load. Take a good look at the photo below to understand how the tailgate is controlled.
When tailgating, the opening between the bed and the tailgate must be severely limited, or you’ll end up leaving most of the load in a big pile, instead of spread along the driveway. To accomplish that, the chains are taken from their “dump” position on the tailgate, as on the right, and are put into a slot on the truck bed, as on the left. The length of chain left hanging partly determines how thick the stone is spread, as does the speed of the truck while spreading. I’m not so slick at spreading, having only done it a few times, so I luck out and get about 99% dump deliveries. A couple of my coworkers are absolute artists at tailgating and are downright fun to watch. They can look at how far the buyer wants the load to go and get it pretty-much on the money.
I showed the tailgate clamps for those who may have seen them and wonder at their use. When NOT being used, they are swung outward, where they lock down out of the way of the tailgate, as on the left. IF you’re hauling large stone or concrete pieces that could shift during transit and slam against the tailgate, you use the clamps to keep the gate closed (as on the right), since a hard enough jar could, theoretically, pop the gate loose from the latches. That could result in losing product on the highway, thus creating a dangerous situation. We also use them when hauling salt, since it’s dry and might try vibrating through a loose tailgate, plus, winter potholes could possibly jar a latch open and cause you to lose some of your load. Obviously, the clamps must be put in the outward position when you get to your dumpsite. Over the years, not doing so has resulted in a few trucks balancing on their tailgates, while the drivers sat in their cabs looking skyward.
There are also tailgates that hinge on the side, as opposed to the top. So far, I’ve seen them used only when hauling waste material to landfills. There are also grain tailgates, with a small lift-gate in the center of the main gate to control the grain as it pours out into a hopper. I’m sure there are other specialty tailgates as well, but the style shown is the most common. So there you have it, if anyone even cares. If not, there you have it anyway! © 2015