The loading modes of ropes of lifting and pressure mechanisms of a quarry excavator with working equipment straight shovel are characterized, as the results of experimental studies show, by sharp fluctuations in effort and speed. Features of functioning of the main drives of a quarry excavator in the process of rock excavation under the combined action of mechanisms (lifting and pressure) are revealed. It is shown that when the mechanisms work together, a two-crank-lever transmission mechanism is formed, connecting the main mechanisms with the bucket, and a common transmission mechanism of the main drives, including the main mechanisms and the lever mechanism. It is established that the initial link of the General transmission mechanism, the coordinates of which determine the positions of all the links of the mechanism relative to the rack (boom), is the link "handle-bucket". It is shown that one of the reasons for the loading modes of ropes is the inconsistency of the working movements of lifting and pressure with the joint action of the main mechanisms in the process of rock excavation. Dependences are obtained for determining the kinematic transfer functions of the lever mechanism, i.e., the relationship between the lifting and head speeds and the digging speed when moving the bucket (the top of the cutting edge) along a given trajectory during the working of the face. It is established that in this case, the operating parameters of the main mechanisms (speed and force of lifting and pressure) are determined depending on the position of the bucket in the working area of the excavator. The relations between the parameters that characterize the bucket position in the bottom hole and the operating parameters of the main mechanisms are determined. The method of forming the bucket movement trajectory during working out of an excavator face, based on the model of a single step of bucket movement, is developed. The proposed method will ensure the coordination of the main mechanisms when they work together in the process of rock excavation. On the basis of kinematic and power analysis of the lever mechanism, dependences are obtained for determining the operating parameters of the main mechanisms (forces, speeds, and power of forces) for the specified power parameters implemented on the bucket. A simulation model of the process of rock excavation with working equipment straight shovel of a quarry excavator has been developed. The results of the study can be used in the development of the main drive control system.