Theoretical study of damaging pomaceous fruits during machine harvesting

The article presents theoretical studies of contact of fruits with each other and with the transporting organs of the harvesting unit. Such contact is the main cause of damage, which negatively affects the safety of crop and the quality of products sold, and hence its cost. The paper considers the main, most probable ways of fruit contact: impact of fruit on a hard surface, impact of two free fruits and impact of fruit on the surface of densely lying fruits. It has been determined that fruits that are in contact during free rolling on the working surface receive the greatest damage. This is due to the fact that the contact pressure during the collision of free fruits is greater than the pressure when the fruit hits a flat surface. As a result of the study, the permissible speed of falling apples on the surface of their tightly lying fruits is 1.9 m/s at a falling height of 0.183 m and a ratio of the radii of the contacting fruits k = 1/2, or 1.25 m/s and 0.08 m at k =1, or 0.67 m/s and 0.023 m at k = 2. The results of the research were applied by Scientific and Practical Center of the National Academy of Sciences of Belarus for Agriculture Mechanization in the development of a self-propelled universal unit for picking fruits and forming branches of fruit trees ASU-6.