The Development of Excavators in 20th Century (1)

Since the late 20th century, the international production of excavators has developed in the direction of large-scale, miniaturized, multi-functional, specialization and automation.

1. Develop multi-variety, multi-functional, high-quality and high-efficiency excavators. In order to meet the needs of municipal construction and farmland construction, micro excavators with bucket capacity below 0.25m³ have been developed abroad, and the smallest bucket capacity is only 0.01m³. In addition, the largest number of medium and small excavators tend to be multi-functional in one machine, and are equipped with a variety of working devices - in addition to front shovel and backhoe, they are also equipped with hoists, grab buckets, grader buckets, loading buckets, and rakes. Tooth, crushing cone, twist drill, electromagnetic suction cup, vibrator, bulldozer, impact shovel, container fork, aerial work frame, reel and dragline, etc., to meet the needs of various constructions. At the same time, develop special excavators for special purposes, such as low specific pressure, low noise, underwater special and amphibious excavators.

2. The rapid development of full hydraulic excavators, continuous improvement and innovation of control methods, makes excavators develop from simple lever manipulation to hydraulic manipulation, pneumatic manipulation, hydraulic servo manipulation(hydraulic motor) and electrical control, radio remote control, and electronic computer integrated program control. In dangerous areas or underwater operations, radio control is used, and the combination of electronic computer control receivers and laser guidance can achieve complete automation of excavator operation. All of this, the fully hydraulic excavator has laid the foundation and created a good premise.

3. Attach importance to the adoption of new technologies, new processes and new structures, and accelerate the development of standardization, serialization and generalization. For example, the excavator produced by the German Atlas Company is equipped with a new engine speed adjustment device, which enables the excavator to work at the speed most suitable for its operating requirements; the new C series LS-5800 hydraulic excavator of Lincoln-Belt Company of the United States, the machine is equipped with a fully automatic control hydraulic system, which can automatically adjust the flow and avoid the waste of driving power. CAPS (Computer Aided Power System) is also installed to improve the working power of the excavator and better exert the function of the hydraulic system; five new models of FJ series excavators produced by Sumitomo Corporation of Japan are equipped with computer-aided power systems connected to the hydraulic circuit.

The power control system uses the precise control mode selection system to reduce the consumption of fuel, engine power and hydraulic power, and prolong the service life of the components; the oil pump adjustment system of the excavator produced by the German O&K company has the characteristics of confluence , so that the oil pump has maximum working efficiency; Japan's Kobelco Company adopts an intelligent control system(electric control system) on the new 904.905.907.909 hydraulic excavator, even inexperienced drivers can perform complex operations; German Liebherr Company developed The ECO (Electronic Control Operation) operating device can adjust the performance of the excavator according to the operation requirements, achieving high efficiency and low fuel consumption; Caterpillar of the United States adopts the latest 3114T diesel engine and torque on the new B system excavator.

Load pressure sensor  system, power mode selector, etc., further improve the working efficiency and stability of the excavator. South Korea Doosan Construction Machinery Co., Ltd. adopts EPOS-electronic power optimization system on the DH280 excavator. According to the change of engine load, the power absorbed by the hydraulic pump is automatically adjusted, so that the engine speed is always kept near the rated speed, that is, the engine always runs at full speed. Power operation, which not only makes full use of the power of the engine, improves the working efficiency of the excavator, but also prevents the engine from stalling due to overload.