Joystick Hydraulic Pilot Control Unit – Direct Control of Construction Vehicles

The joystick hydraulic pilot control unit is a cost-effective and efficient method for controlling construction vehicles and site equipment. It combines a simple and reliable design with high operational reliability.

Controlling Construction Vehicles: A Challenge

Construction vehicles are characterized by great power and high versatility. They are also very powerful and have a large working range. To ensure these characteristics, hydraulics have established themselves as the most suitable method of power transmission.

With the help of hydraulics, power-mechanical devices can be flexibly designed and equipped with almost arbitrarily high working forces. However, the pressures required in the hydraulic lines pose a challenge for control.

An excavator operating with a working pressure of up to 500 bar cannot be operated via direct hydraulic controls. The risk for the excavator operator is far too great. A bursting line or a failing seal is enough, and the excavator operator is exposed to a sharp jet of hot hydraulic fluid. To address this problem, there are two approaches for controlling construction vehicles:

• Electro-hydraulic Control
• Control with Joystick Hydraulic Pilot Control Unit

Difference between Electro-hydraulic Control and Hydraulic Pilot Control Unit

The joystick has proven itself for controlling excavators. With this compact tool, the operator can perform a multitude of functions. The usual functions of the work joystick are as follows:

• Arm Lift and Lower
• Stick Lift and Lower
• Rotate Upper Carriage Right and Left
• Open and Close Tool
• Rotate Tool

Driving is usually done with the other joystick. This joystick controls forward-backward and right-left rotation.

The electro-hydraulic control has small electrical switches built into the respective buttons and positions of the joystick. These lead to remote control valves, which regulate the excavator’s hydraulics in the desired manner.

With the joystick hydraulic pilot control unit, the control pressure is directed directly into the operation via a pressure reducing valve. When the joystick is tilted or operated, small valves located underneath are opened. When released, the joystick returns to its neutral position and the valves are closed again by a compression spring.

Advantages of the Joystick Hydraulic Pilot Control Unit

The hydraulic control of construction vehicles offers the following advantages:

• lower design effort
• better emergency running properties

In practice, joysticks for construction vehicles today are combined systems of hydraulic and electrical control. Important working movements are preferably controlled purely hydraulically. This reduces the design effort and enables the use of inexpensive components. However, some control commands can only be executed electronically, which is why combined joysticks have become prevalent.

However, safety in emergency operation is crucial for construction vehicles. In the event of an electronic failure, the vehicle must still be able to be safely shut down. This is ensured by hydraulically operated joysticks. Even with the engine switched off, a defective pump, or failed electronics, the excavator arm can still be lowered and the vehicle secured.