Generally, they consist of a power unit, transmission unit, traveling device, and working device. Principle: They are earthmoving machines that use a bucket to excavate materials above or below the machine's bearing surface and load them into transport vehicles or unload them at a stockpile. They are self-propelled mining machines that use a bucket to scoop up excavated material or mineral products from the working face and transport them to a discharge point for unloading.
History: The development of mini excavators progressed from steam-powered bucket rotary excavators to electric-powered and internal combustion engine-powered rotary excavators, and finally to fully automatic hydraulic excavators using mechatronics technology.
Due to the application of hydraulic technology, in the 1940s, suspended excavators with hydraulic backhoes mounted on tractors were developed. In the early and mid-1950s, towed full-rotation hydraulic excavators and tracked full-hydraulic excavators were successively developed. Early prototype hydraulic excavators used hydraulic technology from aircraft and machine tools, lacking hydraulic components suitable for various excavator operating conditions, resulting in unstable manufacturing quality and incomplete parts. From the 1960s onwards, hydraulic excavators entered a stage of promotion and rapid development, with a rapid increase in the number of excavator manufacturers and models in various countries, and a surge in production. Between 1968 and 1970, the production of hydraulic excavators accounted for 83% of the total excavator production, approaching 100%.
