Excavators are indispensable machines in the construction industry, and their control levers play a crucial role in their operation. Understanding how these levers work can help operators use the machines more effectively and safely.

Two Main Control Patterns

There are two primary control patterns for excavators: ISO and SAE. The ISO pattern, also known as CAT or excavator controls, is more prevalent worldwide. In this pattern, the right-hand lever controls the boom and bucket, while the left-hand lever manages the arm (dipper) and swing movements. On the other hand, the SAE pattern, often referred to as John Deere or backhoe controls, is more common in the United States. Here, the right-hand lever operates the arm and bucket, while the left-hand lever controls the boom and swing.

How ISO Controls Work

In the ISO pattern, moving the right-hand lever toward the operator raises the boom, while pushing it away lowers the boom. Tipping the wrist to the left curls the bucket in (to close it), and tipping it to the right curls the bucket out (to dump materials). The left-hand lever, when moved toward the operator, brings the arm closer, and pushing it away extends the arm. Moving the left-hand lever to the left or right swings the excavator\\\\\\'s cabin in the corresponding direction.

How SAE Controls Work

In the SAE pattern, the left-hand lever controls the boom and swing. Moving it toward the operator raises the boom, and pushing it away lowers the boom. The right-hand lever operates the arm and bucket. Bringing the right-hand lever toward the operator brings the arm closer, and pushing it away extends the arm. Tipping the wrist to the left curls the bucket in, and tipping it to the right curls the bucket out.

The Role of the Main Control Valve

The main control valve (MCV) is a key component in the excavator\\\\\\'s hydraulic system. It controls the flow of hydraulic fluid throughout the machine, directing it to the specific cylinder to create the desired movement. For example, when the operator moves a lever to extend the arm, the MCV directs fluid to the cylinder near the arm, causing it to extend. When the lever is moved to retract the arm, the fluid is drained from that cylinder.

Customization and Safety

Modern excavators often come with a lever that allows operators to switch between ISO and SAE control patterns. This feature is particularly useful for operators who are accustomed to one pattern and need to work with a machine that uses the other. Additionally, some excavators are equipped with safety levers that prevent unintended movements when the control box is tilted. This system ensures that the power is cut off unless the safety lever is actively operated, reducing the risk of malfunctions caused by operator error.

Understanding the working principles of excavator control levers is essential for efficient and safe operation. Whether an operator prefers the ISO or SAE pattern, knowing how to switch between them and how the main control valve functions can significantly enhance productivity and safety on the job site.