Studies of Cherry Harvesting by Shaking Small Limbs

日本的加工樱桃产量约为4,000吨/年。所有这些都是手工采摘的。由于劳动力短缺的问题，机械收获一直是人们所期望的。在1994年，我们尝试了通过使用商业日本杏振动器振动樱桃树的小树枝来收获樱桃果实。1995年，我们对振动筛进行了改进，使其产生更大的行程（8 cm），并进行了田间试验。结果表明，该品种果实采收率高，落果多为果柄落果。1996年，我们将大行程发生箱移到臂底，并在臂尖设置夹钳代替吊钩，实现了单人连续作业。田间试验发现，机械收获应在成熟前进行，通过振动试验和拉拔试验，研究了樱桃果实的可摘性。在6 ~ 8 cm行程的振动试验中，获得了带柄果实。而无柄果则是由每枝多果多叶的系统造成的。拉力试验中，由于果实质量较小，枝梗与果柄之间的分离力（SS力）低于果柄与果实之间的分离力（SF力）。但当质量增大时，SF力约为SS力的三分之一。樱桃果实被反方向拉动时，分离力极低，通过改进枝条修剪整枝方法和栽培方法，使振动法樱桃收获实用化。

Process-cherry production in Japan is about 4,000t/year. All of these are harvested by hand picking. Because of the problem of shortage of laborers, a mechanical harvesting has been desired.In 1994, we tried to harvest cherry fruits by shaking small limbs of cherry trees using commercial Japanese apricot shakers. Then many stalkless fruits were induced.In 1995, we modified the shaker so that it may generate a larger stroke (8cm) and field test was conducted. The results obtained showed that the fruits harvesting percentage was high and most of the dropped fruits were with their stalks. The products, obtained by processing immediatly after harvesting, were with little damage.In 1996, we transfered a large stroke generating case to the bottom of the boom and set the clamp instead of the hook at the tip of the boom, thereby a single man could perform harvesting operations consistently.In field test, it was found that a mechanical harvesting should be done in pre-stage of maturity, the vibration generated by the shaker could hardly be transmitted to the slender limb and the bark hardly was damaged during the harvesting operations.A vibrating test and a pulling test were carried out in order to investigate the detachable properties of cherry fruits. In the vibrating test with 6 to 8 cm of stroke, fruits with stalk were obtained. But the stalkless fruits were resulted from the system which had many fruits and leaves per the spur. In the pulling test, the detachment force between spur and stalk (SS force) was lower than that between stalk and fruit (SF force), as the fruit mass was smaller. But when the mass became larger, SF force was about one third of SS force. As a cherry fruit was pulled in the opposite direction of stalk, the detachment force became extremely low.By improving the pruning and training methods of branches and the methods of cultivation, the vibrational process-cherry harvesting will be able to be used practically.