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How Caterpillar Backhoe Loaders Work


Operating the Backhoe Loader
This is a standard mechanical linkage control system from a backhoe. When you move the stick on the far left, it operates the spool valves that move the boom from side to side and forward and backward. The stick on the far right operates the spool valves that move the stick and the bucket. The two center controls move the spool valves that extend and retract the stabilizer legs.
This is a standard mechanical linkage control system from a backhoe. When you move the stick on the far left, it operates the spool valves that move the boom from side to side and forward and backward. The stick on the far right operates the spool valves that move the stick and the bucket. The two center controls move the spool valves that extend and retract the stabilizer legs.

When you stop and think about all the different moving parts in a backhoe loader, it seems unbelievable that you need only one person at the controls. As we saw in the last two sections, the backhoe arm swivels on four different hinges (some bucket designs have five) and the loader moves on two to three hinges. Additionally, the operator controls the stabilizer arms and moves the tractor around while loading. How does one person do all of this?

The main controls for a Caterpillar backhoe are two computer-style joysticks. Here are the functions of the joysticks:

  • The joystick on the left moves the boom and swings the entire backhoe from side to side.
  • The joystick on the right moves the stick and the bucket.
  • Pulling the joystick toward you moves the boom or the stick closer to you, and pushing the joystick away moves the boom or stick farther out.
  • Pushing the left-hand joystick to the left swings the entire backhoe to the left, and pushing the joystick to the right swings the arm to the right.
  • Pushing the right-hand joystick to the left scoops the bucket in, and pushing it to the right dumps the bucket out.

Digging effectively with a backhoe requires practice, like learning to drive a car. The hardest part of learning to drive is usually paying attention to all of the different things going on. It takes a lot of practice to keep all of the various controls in your mind at once. Learning how to operate a backhoe is the same way. Picking up something with your arm is incredibly easy because you move every muscle automatically. But imagine how hard it would be if you had to stop and think about every muscle you were moving in that one simple motion.

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An experienced driver doesn't even think about most of the things he or she is doing while driving. Backhoe operators reach this same level. With enough practice, the controls become second nature. But in addition to learning the controls, the operator must also learn to position the arm so that it will dig efficiently. That means knowing the best angle for the bucket as it sinks into the dirt, knowing when to move the boom and when to move the stick and getting a sense of what arm positions provide the best leverage.

Operating the loader is relatively simple because it only dumps, raises and lowers. The main loader control is a joystick on the right-hand side of the operator. If you pull the joystick back toward you, the first set of hydraulic rams push out to lift the arms up. When you push it away from you, the arms lower. To dump out the bucket, you move the joystick to the right. To scoop the bucket in, you move the joystick to the left.

So the loader is pretty easy to learn compared to the backhoe. To get much use out of it, however, you have to be able to operate it while moving the tractor around the site. The tractor basically handles like a car, with a steering wheel, accelerator, brake pedal and gear shift. The loader and the tractor are powered by the same engine, which has a variable speed control. For an extra boost in loader force, the operator can put the tractor in neutral so that most of the engine's power goes directly to the hydraulic system.

Experienced backhoe operators use the backhoe loader in much the same way you would use a shovel or wheelbarrow at home -- they know exactly how to move the controls to dig and load quickly and effectively. And they're always thinking ahead to their next few moves, planning their strategy. This is also something like driving a car: When you see a traffic jam ahead of you on the road, you're already deciding how you're going to navigate it. Just as with driving, learning how to operate the backhoe is only the first step -- the real skill is in knowing how to use the backhoe to accomplish different tasks.


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