Evaluation of Quality of Harvest and Mechanical Aspects Related to Beater Adjustments in Mechanical Grape Harvesting.

The research was conducted on a trailed grape harvester that allows independent adjustment of the frequency and amplitude of the beaters movement. The range of amplitude is between 30 to 90 mm and is managed by the operator using an electromechanical control. The objective of the research was to evaluate the effects of these adjustments and the possibility of using them to improve the grape harvester performance. Harvest quality was evaluated by checking the condition of the detached grapes, level of plant defoliation and amount of visible and concealed losses. The mechanical action of the harvester was evaluated at the moment of grape detachment, measuring the stresses transmitted by the beating system. The dynamic effects of adjustment of the beater movement amplitude were similar to those of the frequency adjustment, affecting the number of stresses, the transmitted power and displacement caused, but not the acceleration values. Compared to frequency control, the adjustment of beater movement amplitude also provides greater possibilities to use higher forward speed. The variation of the amplitude of the beater movement has proved an adjustment in many ways similar to the frequency variation and can be used to improve grape detachment or to increase grape harvester productivity.