The development and widespread introduction of domestic hydraulic mining excavators is constrained by the lack of a strategy for their creation, taking into account modern trends in the development of technology, foreign and domestic experience in the design and operation of hydraulic mining excavators. Such a strategy should be based on a systematic approach to the analysis and assessment, first of all, on the principle hydraulic scheme of the functioning of the working equipment of hydraulic mining excavators. The existing technical level of the construction of the working equipment of open-pit hydraulic excavators does not fully meet the requirements of the modern mining industry. Consequently, the development of a basic hydraulic diagram of the working equipment of hydraulic excavators, which will improve the technical and economic performance of hydraulic excavators, is an urgent scientific and technical task that meets the needs of mining. The aim of the study is to substantiate and develop a new principal hydraulic scheme of the working equipment functioning to increase the efficiency of domestic hydraulic shovels of the "front shovel" type. Research methods include generalization and analysis of literary sources, theoretical and experimental research methods based on the classical laws of mathematics and physics, hydraulics, etc. As a result of the research carried out, a new principal hydraulic scheme has been proposed, which will allow: to use double-acting hydraulic cylinders for the boom drive with lowering of the boom under the influence of the mass of the working equipment; when lifting the boom with simultaneous rotation, the platform speed will depend on the pumping unit capacity and the settings of the safety valves (normal speed); when lowering the boom with simultaneous rotation, the platform speed can be increased due to recuperation (recuperation is a disabled function); when the oil station is turned off, it is impossible to forcibly lower the boom under its own weight even when the distributor is activated (safety function).
