Studies on the mechanical harvesting of tree fruits (I)

Abstract

The author and his colleague have studied on the mechanical harvesting of tree fruits—cherries, apples, chestnuts and others—since 1964, and the principal results are as follows:
1) About 740 literatures on the mechanical harvesting of tree fruits both in Japan and other countries were investigated and classified into such groups as physical properties of trees and fruits, pruning, harvesting machines, catching devices, containers, transportation or handling and so on.
2) Five small portable and one self-propelled (8 PS, 420kg) harvesting machines have been manufactured for trial in order to fit to the Japanese orchard under such conditions as small scale, hillside cultivation and the various sizes of trees. Most of the pootable types could not shake the branch well because of insufficient weight, nevertheless these machines were too heavy to be carried in the orchard. The crawler type was able to shake effectively the trunk of about ten-year-old cherry trees.
3) The clamp developed in this study hardly wounds the tree bark and is able to hold the branches promptly and firmly.
4) A catching frame having two layers of deceleation strips made of canvas webbing was constructed for the mechanical harvesting of apple fruits. The strips of 4cm wide, which were fixed on the frame at an interval of 2cm, acted effectively on deceleration. Many fruits, however, were slightly bruised by the mutual impact while they were rolling downwards on the catching surface.
5) The force and the frequency required to remove a fruit from a spur and also the coefficient of viscous damping of cherries were examined. The results obtained are indicated in Table 12 and Table 13.
6) Some experiments on removing fruits from spurs were carried out with the shaking device in the laboratory, and the relations between the removing time, the frequency and the amplitude were made clear. These results are shown in Fig. 11-14.