Structure and working principle of excavators

16 February,2017


The first excavator was invented by Mr. William Smith Otis in the United States in 1837, which was powered by the steam at that time. The first swing mechanical excavator was invented in 1895, a milestone in the excavators history. The first hydraulic excavator was created in 1960s, in Germany, than it was introduced to Japan and other places, being widely applied across the world.

Named as the single armed Hercules, the excavators are commonly used in the construction industry, including excavation, loading, lifting and other application. From the industrial solutions side, it could be employed in civil engineering or heavy construction, building, pipe laying and private utilities, extraction, site preparation job, wood handling, recycling and waste management.

The structure of excavators can be divided into three parts: attachment, upper frame and under carriage. Main working attachment contains stick cylinder, boom, boom cylinder, stick, bucket cylinder, linkage, and bucket. As per the types of bucket arrangement, there are two popular kinds, backhoe and face shovel, and among them, backhoe is mostly common used.

The main parts of the upper structure includeswing assembly, counterweight, hydraulic pump, engine, main control valve, operation cab and swing platform. All movement and operation of a hydraulic excavator are completed through the use of hydraulic fluid, with hydraulic cylinders and hydraulic motors. Due to the linear actuation of hydraulic cylinders, their mode of operation is fundamentally different from cable-operated excavators which use winches and steel ropes to accomplish the movements.

The under carriage includes track, swivel joint, swing bearing, travel device, idler wheel, carrier roller, sprocket wheel, track roller, and X-frame. According to the types of ground contact, there are crawler excavator and wheeled excavator, and according to the length of undercarriage, it has stander crawler and long crawler.


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