One of the promising working units for pre-sowing soil preparation, in particular, for pre-sowing soil cultivation for potatoes, are still the disk tillage. Studies of a number of authors determined, that the disc units with continuous cutting edge are more energy intensive, less resistant to running and sensitive to changes in the load and working units with a serrated cutting edge has significant advantages. However, not all gear working units are able to perform advanced agronomic requirements. The rational parameters of developed by the working units, can only be determined on the basis of a study of the process of its interaction with the soil, but in relation to working units with a serrated cutting edge, this question is poorly understood. Working unit movement with respect to the adopted reference system, can be regarded as fully qualified only, when we know the movement of its each points in the same frame of reference. Therefore, the disk working unit is considered a with the teeth, the cutting edge of which is made by a logarithmic spiral curve, providing moving cutting of soil and plant remains in motion, and the back edge is in a straight line, connecting the toe of each tooth with the center of the disk. As a result of calculations, based and the equations of motion for an arbitrary point of the cutting edge of a tooth of a flat disk of the working unit, which allows to build a trajectory in space, determine the velocity and acceleration of the blade points at any given time.

Justification and analytical derivation of the equations to determine the basic parameters (including forms) of rotary (circular, screw, a helical-type and etc.) working parts of tillers were the subject of investigations by several authors. Also from literature sources, we can say that the working parts of passive rotary actuator (jet - the drive from the soil) for the crumbling of the soil and associated operations will require further theoretical and experimental studies. Therefore, we investigated spiral plate-type working part with corrugated (wavy) work surface and a cutting edge with teeth, accomplished at the site of the logarithmic spiral. Thus, the wavy form of the working surface has an influence on the cutting edge. In consequence of that, the teeth of the cutting edge radially disposed on a path, extending along a helical line and rejected in two directions (right and left turn). Based on the foregoing, we justified and prepared relations to define the basic parameters of the working surface of the teeth and the cutting edge of the working part spiral plate-type elements: the diameter (D), the number of teeth (Z3), the depth of cut (C'), the distance between adjacent teeth - tooth pitch (S3 ), length of the front cutting edge of the tooth (ℓ 3), the length of back edge of the tooth (ℓ t), lead of a screw (tmax), the width of the operating element (H), width of a tooth at its apex (B3) and the distance from the apex of the tooth to its leading edge (L3 ). The analytical dependence can justify the choice of the main design parameters of the operating element and design the toothed spiral plate-type working part, which is reduced to the calculation of the basic dimensions and meaningful implementation.

The article deals with the spiral-plate working unit, configured with teeth, the cutting edge (blade) of which is made on site (curve) of the logarithmic spiral. Each helix of studied working unit (taking into account properties of a helical surface or a line) is set at an angle and lift the helix has an angle of rotation generator (i.e., the helix angle of twist). In this case, to create the motion equation of any point of the teeth’s motion, the working unit is in the spatial coordinate system 0xyz so that the origin was in his heart.

The article deals with the interaction process of blade cog of disk-shaped spring (spiral-plate working unit) with the soil. At the same time, taking into account that the intensity of the impact of blade working unit on the ground depends on the speed of its movement, with an increase of which, increases the surface tillage on depth of stroke and cutting weed roots, determined the rate of blade cog at any point, and on the basis of differentiation of its motion equations, and after some transformations, we obtain a formula for determining the cutting speed of any point of the blade cog of disk-shaped spring. We also determined the total acceleration of considering point and the analysis of dependency was carried out.

The article refers to the agricultural engineering and mechanization of agriculture, particularly to methods of ridges forming and designing the shaped work surface of hillers. The aim of the study is to design a working surface form of the hiller’s blade to form an air- permeable crests. This goal is achieved by the development of methods of designing the shaped work surface of the hiller. The article describes the sequence of design the shaped work surface of hiller. At the same time, we took into account the existing design techniques, taking into account the working conditions and terms of agronomic requirements, but also took into account the physical and mechanical properties of the soil, the conditions for the growth and development of the potato (and other cultures). The designed form of the working surface of the hiller’s blade forms an air - permeable crests with the least expenditure of energy and increases the yield by: lifting and crumbling of the soil, moving it up the dump, separation (screening) on a sieve placed between the legs and wings of solid blade, turning the soil to 90 ... 120 degrees, loosening the surface ridges and filling the weeds are in the protection area, the direction of erosive - the dangerous part (forming a crust on the ridges and increases its density) of the soil at the bottom of the furrow .