The article presents the results of theoretical studies to determine the mathematical model of the movement of a piece of cotton along the splitter of the cleaner drum. The problem of determining the trajectory of movement in the zone of supplying a part of cotton to the saw drum of the zone of cleaning cotton from large litter is solved. Based on the analysis of the obtained trajectories of movement of a part of the cotton and the constructed graphical dependencies, the value of the distance between the axes of the pile and saw drums is substantiated.