Date of Award
Master of Science
John J. McDow
Arthur Morgan, Homer D. Swingle
This study was conducted to evaluate a basic and new principle for vegetable harvesting. A tractor mounted machine, using an auxiliary engine as the power source, was designed and constructed primarily for harvesting snap beans with limited tests on bell peppers. It incorporated a cylindrical helix and a cylindrical brush as the picking mechanism. Both laboratory and field tests were conducted to determine picking efficiency and plant and fruit damage in relation to the forward speed of the machine, the angular velocity of the helix, and the ratio of the angular velocity of the helix to that of the brush.
The average picking efficiency for peppers was 71 percent with a high of 89 percent for one trial. Statistical analysis of the results from laboratory tests and field tests on snap beans showed that all three variables significantly affected both picking efficiency and plant damage. Results from laboratory tests showed that as the speed of the helix increased and the forward speed of the machine decreased, the picking efficiency increased and plant damage decreased for the range of values tested. Results from field tests showed that a 1;1|.5 ratio of angular velocity of the helix to that of the brush resulted in the best picking efficiency and the greatest plant damage for each level of angular velocity of the helix. The highest picking efficiency in the laboratory for snap beans was 97 percent and in the field was 8? percent. Damage to both picked peppers and snap beans was severe; however, it was concluded that the major damage was due to inadequate means for the fruit to exit from the harvester.
Shadden, Richard C., "Design and evaluation of an experimental helical vegetable harvester. " Master's Thesis, University of Tennessee, 1969.