1、毕业设计(论文)外文资料翻译院 系专业学生姓名班级学号外文出处AGRICULTURAL MECHANIZATION ASIA，AFRICA AND LATIN AMERICA 2004 VOL.35 NO.1指导教师评语：指导教师签名： 年 月 日Development and Testing of a Tractor-mounted Positioner for Mango HarvestingR.A. Gupta，R.M. SatasiyaPramod Mohnot ，N.K. GontiaAbstractIn order to reduce losses sustained during
2、 harvesting of mango and to maintain fruit quality, a tractor- mounted positioner was developed and tested for mango harvesting at the Sagadividi farm of the Gujarat Agricultural University, Junagadh Campus. During operation, it was observed that using the positioner for harvesting, only the mature
3、fruits with stalk of 10-20 mm length without sap bums and any other damage to the fruits, could be harvested. White layer (bloom), which is desirable from quality point of view, was also maintained. Though the work output was slightly reduced over all economics was in favour of the use of the positi
4、oner for harvesting as compared to the traditional picker. Using a positioner in orchards can save about Rs. 1,000 per tree in a good season.IntroductionMango (Manaifera indica),、the “king” of fruits, has prime importance among the commercial fruits grown in India-the largest producer and exporter o
5、f mango in the world. In Gujarat about 382 thousand tonnes of mango is produced annually over an area of 57 thousand hectare (Data book 2000). Gujarat produces export quality of mango mainly the Alphonso and Kesar varieties. The latter has excellent quality for export and grown almost throughout the
6、 state, concentrating in South Gujarat and Saurashtra. The quality of the fruits mainly depends on their maturity stages , harvest and post harvest techniques adopted by the mango growers.Harvesting of fruits in India is mostly done manually by means of a curved knife, pair of scissors or blades att
7、ached to a hanging basket to the distal end of bamboo sticks (Devnani, 1980). For harvesting mango, hand picking manually operated low capacity gadgets and tree shaking methods prevaile which results in high labour and energy requirements, drudgery, damaged fruits, damage to tree branches etc. The d
8、amage and bruising are very serious problem. The fruits should not be allowed to fall on the ground as the injured fruits cause spoilage to other healthy fruits during packaging and storage. Fruits harvested with 8-10 mm long stalks appear better on ripening as undesired spots on the skin caused by
9、sap bum are prevented. Such fruits are less prone to stem end and rot and other storage diseases (Sapovadia et. al. 2001).RTTC, Jurhat, Assam (1988) worked on fruit harvesting devices. The manually operated unit worked on the principle of individual fruit cutting by sickle / blade and collecting the
10、 fruit in a bag. The unit was found suitable for average size and big fruits, which would be damaged if allowed to fall freely on the ground. The other unit worked on the principle of mechanical shaking of tree. This unit was suitable for hard fruits. Brown and Schertz (1967) also worked on mechanic
11、ally operated harvesters and reported that fruits harvested by mechanical shaking have more injuries in the form of splits, internal and external bruising and superficial peel scars than manually harvested fruits.RTTC, Gujarat Agricultural University, developed an improved picker and it showed bette
12、r performance as compared to other pickers collected from various centres of the country. About 90% of the fruits could be harvested with stalk of 10-20 mm in length, which is most desirable specifically for export quality of fruit. Fruits should be harvested manually using mechanical aids like a po
13、sitioner on which a person can stand and pick the fruit using a pair of scissors / secateure. As the fruits are picked form very close distance hence, only mature fruits are harvested without any damage. Hence, keeping the foregoings in view, a study for developing and testing of a trac- tor-driven
14、and hydraulically operated positioner was undertaken at the centre. Material and MethodsPrior to the design of the machine some preliminary information regarding the tree characteristics were studied to ensure that the movability of the machine in the field, distribution of fruits within the tree an
15、d the percentage of fruits that can be harvested are estimated (Tables 1 to 3). The height of the machine and size of the cage were likewise studied. Using the above information a hy- draulically-operated positioner for harvesting mango and other fruits, was designed and developed. The safety factor
16、s were also taken into consideration. The cost of the machine was kept minimum by reducing the number of moving components in the design of the machine.The machine consists of a frame, three-point linkage, hydraulic jack, supporting links, extension pipe and cage. The frame of the machine is fabricated from angle iron of (50 50 6) mm
