The aim of research was to develop a mathematical model of interactions of plant stems with a screw cutterbar cutting blades. The main advantage of a screw cutting system is the availability of one toola screw belt conveyor, on the circuit periphery of which the flat blades ensuring cutting, grinding and transporting the plants from the cutting zone are installed. During the study, a mathematical model of interaction of the blade cutting device with a large amount of plants was worked out. By substituting technical data of cutterbar in the formula of this model using Microsoft Excel software program the graphs of dependence of the blades trajectory in the cutting zone of the plant stems and movements of the two adjacent ends of the blades are built. By analyzing the graph of trajectory of two adjacent ends of the blades of knives, the authors concluded that the distance between any consistent homogeneous points of adjacent segments of trochoids of adjacent blades is equal and it is the calculated cutting length. As a result of theoretical research a formula to calculate the plant cutting length by screw cutterbar cutting blades was deduced. According to the parameters of the formula, it’s evident that the estimated length of the plant sterm cut by screw cutterbar cutting machines depends largely on their geometric parameters, rotating velocity and feed velocity rate. This formula is intended for calculation of technological and geometrical parameters of screw cutterbar cutting machines in their design, providing simultaneous cutting and grinding of vegetation to such an extent that it couldn’t be accumulated at passages and outlets of reclamation canals when entering them.
Keywords: screw cutterbar cutting machine, plant stems, blade, cutting, equation, cycloid, trochoid, trajectory, movement.
