(44(3):335-343)Experiment and Improvement of the Pruning Machine for Fruit Orchard

配合亞熱帶果樹如荔枝等之密植栽培，利用機械修剪以矮化果樹，便於採收與管理之構想，設計截頂角錐型整修機。整修機經數度田間試驗與改良後，目前已研製完成；其機長316公分（作業時250公分），寬120公分（作業時405公分），高201公分，動力源為16HP／2,200rpm柴油引擎，行走部為四輪驅動、四輪轉向，行駛速度1.0～15公里／小時，最小轉彎半徑2公尺，車身最低離地距離13公分。側整枝刀組及三層水平整枝刀組均裝於同一機架上，並以同一樞軸為迴轉驅動中心；機體左右兩側各有整枝機構一組，分別以一支油壓缸控制剪切刀之展開與收縮，操作簡便。剪切刀為往復式三角鋸齒刃，齒刃距50公厘，往復切割每分鐘300次左右，作業時行駛速度低於0.3m／s為宜。果樹栽培行距小於3.3公尺者，每一行程可同時進行兩側修剪作業。栽培行距超過3.3公尺以上者，則以採用單側修剪作業之效果較理想。本機經田間實際作業與調查顯示，荔枝經機械修剪後平均樹高為180公分，生長至採收時平均樹高則為235公分，除可獲得矮化樹型之預期目標外，若能配合相關之栽培管理技術，修整作業則不影響荔枝之生長、開花與結果。The objective of this study is to develop a machine that is suitable to dwarf subtropical fruit trees by pruning the top and the sides of the tree as a top flatted cone for easily handling. The machine has been manufactured, tested and improved. The dimensions of the machine are 316cm in length, 120cm in width and 201cm in height. It changed to 250 cmx405cmx20lcm when cutters are extended out for pruning operation. The power is supplied by a diesel engine rated l6Hp at 2,200rpm. This machine has four-wheel drive and four-wheel steering chassis. The minimum steering radius is 2.0 meters. The travelling speed of the machine is between 1.0 and 15Km/hr and the clearance between the machine and the ground is 13 cm. The vertically oriented side cutter and horizontally oriented 3-step pruning cutters on either side were seated on a square pipe frame which controlled by a hydraulic cylinder that might be rocked horizontally on its axis. The two sets of such elements form the pruning mechanism. The mechanical type reciprocating cutter knife has a pitch of 50 mm with an optimum working frequency of 300 cycles/min. The best performance travelling speed is under 0.3 m/sec. When row distance of litchi trees is less than 3.3 meters, the cutters can reach both sides of the adjacent tree and trim them .If the row distance is over 3.3 meters, the machine can be used to prune only one side of the tree in one operation. The field study indicated that the averaged height of the litchi trees after pruning is 180cm, as they grew up to the time of harvesting, the averaged height is 235cm. This pruning machine can meet the demand of dwarfing litchi trees without affecting their growth, blooming and fruiting