At present, the walking control mode of common crawler excavators is basically the same. There are two parallel walking joysticks on the floor in front of the driver's seat. Each joystick controls one side of the crawler and can only swing back and forth. When the excavator is moving forward/backward, two joysticks need to be operated synchronously, while when the excavator is not synchronized, the excavator will turn due to the different speeds of the crawler on both sides. In order to control walking when the hand is not convenient, there are pedals on both sides of the walking joystick to control with the foot.

The common walking control of crawler excavator adopts the form of double joystick and foot pedal

Although the above walking control method is familiar to everyone, it is only one of the control methods. Not all excavators are like this. In fact, this is the Japanese walking control method, which has been adopted by other manufacturers with the popularity of Japanese excavators. There are many excavators that do not use this kind of walking control, such as liebherr and O&K (now carter 6000 series) in Germany, which only use the foot pedal to control.

Walking control of the carter 200 series excavator

Caterpillar had a 200-series before the 300-series, and the 200-series had interesting walking controls, with an industrial joystick between the pedals that could only swing from side to side. Each pedal synchronously controls both sides of the crawler, which is responsible for forward and backward respectively, and when steering is needed, the joystick is used to coordinate. This way is simple and intuitive, daily operations often only need a short forward or backward, so do not need to use hand. The 300 series, developed in Japan, replaced the 200 series with the popular two-bar format.

Demarker excavator, shown in yellow circle is the walking joystick

In addition, Germany's DEMAG, before it was acquired by komatsu, had a short joystick on the left side of the driver's seat in addition to the front pedal to control walking. Similarly, the German atlas excavator once owned by terex also adopts the same way, except that the walking joystick is set in the middle of the pedal, so it adopts a long rod, but the control mode is the same as DEMAG. Here the atlas excavator as an example of its introduction.

The walking control of the atlas excavator

In fact, there is nothing high-tech about the change from a two-bar to a single-bar. Just like in the early days when excavators used a row of joysticks, but later they were simplified to two joysticks, only the freedom of joysticks was increased, and two sets of hydraulic control valves could be controlled at the same time. In this way, tracks on both sides could be controlled at the same time. We can understand it this way: left and right movements control one side of the track, and front and rear movements control the other side, then the left front/right front/left back/right back movements are actually equivalent to compound movements, and there will be movements on both sides of the tracks, thus realizing the single-lever operation.

How to operate is clear from the figure above

Of course, for the sake of intuition, the walking joystick can be rotated by 45 degrees, so that the forward is a compound action, and both sides of the tracks are walking forward, and both sides of the tracks are walking backward. Then the left and right are both sides of the caterpillar reverse, in situ. If you want to walk with one track, you only need to operate at a 45 degree Angle. Visible, horizontal bar operation walking is also very intuitive and convenient.

Early crawler hydraulic excavators had multiple joysticks

Actually all have their own advantages and disadvantages of each way, it's hard to say what we will be much better than others, but excavator manufacturers to follow their own technical route on the one hand, on the other hand also consider the user's habits, if most users are accustomed to a form, other manufacturers will follow up, eventually form consistent with the situation. In addition to the previously mentioned carter 300 series, komatsu switched to the popular two-shot approach after acquiring DEMAG and incorporating the old product line into the PC series.