4LY-180型油菜聯(lián)合收割機(jī)雙圓筒篩及糧箱的設(shè)計(jì)含25張CAD圖帶開(kāi)題

4LY-180型油菜聯(lián)合收割機(jī)雙圓筒篩及糧箱的設(shè)計(jì)含25張CAD圖帶開(kāi)題,ly,油菜,聯(lián)合收割機(jī),圓筒,設(shè)計(jì),25,cad,開(kāi)題 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 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 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 positioner 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 of 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 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 attached 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 damage 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 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 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 mechanically 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 better 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 positioner 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 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 and 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 factors 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 size. The dimensions and structural members of the frame are shown in the Fig. 1. A hydraulic jack of 2 tonnes capacity with two cylinders is mounted at the centre of the frame with the help of a pin of 40 mm passing through two plates welded to the frame and lower end of the hydraulic jack. The upper end of the jack is supported by fastening three supports to the frame and upper end of the jack. Similarly, the upper end of the piston is fastened to a flange through nuts and bolts. To extend the height of the positioner an extension pipe of 100 mm and 1 m length is attached to the upper end of the piston through flange, nuts and bolts. On the upper end of the extension pipe another flange of the same size (20 20) cm is welded on which cage is fixed through nuts and bolts. The cage of machine is fabricated from angle iron, mild steel flat and wood. The frame of the cage is made out of angle iron. The size of the cage is (92 76 70) cm. At the bottom of the cage, wooden plank is provided. On one side of the bottom an opening of (55 47) cm size is provided through which an operator can get on the positioner to pick up the mature fruits. All the four sides of the positioner are kept folding so that when the machine is on transport from one place to another the sides can be lowered to keep the height minimum.To operate the machine, it is hitched to a tractor through three point linkages and hosepipe of the hydraulic jack is connected to the hydraulic system of the tractor. The cage is mounted on top of the ex- tens4n piece and its sides are folded. The machine is transported to the orchard where mango picking is to be done. During operation, the machine is placed on ground and operator gets on the cage along with a pair of scissor and carton through the opening provided at the bottom of the cage. All the sides of the cage are kept in upright position and hinged to the frame through hooks pins for safety point of view. The hydraulic system of the tractor is operated to lift the cage. As soon as the valve is opened, the oil under pressure goes to jack through hosepipe, which lifts the piston of the jack, thus, the cage is lifted. When required height is reached, valve is closed to stop further upward movement of the cage. Then, the operator pick the fruits from a very close distance using a pair of scissors / secateure. Only matured fruits are picked and kept in the carton.When the carton is full of fruits it is packed and taken on the ground. The machine is taken around the tree to pickup matured fruits. Some of the fruitswhich are located on the top of the tree, are beyond the reach of the operator, are picked using manually operated mango picker.Fig. 1 Tractor-mounted positioner for harvesting mango.Fig. 2 Positioner attached with power Fig. 3 Operator picking mango using positioner.TestingA field testing of the machine was conducted at the Sagdividi farm of Gujarat Agricultural University, Junagadh campus for the Kesar variety of mango which is very popular among in the Saurashtra region of Gujarat state. Thetrees were planted at (12 X 12)m distance. HMT zetor tractor of 35 hp was used to operate the machine. An experienced worker was engaged to pick the fruits in standing posture on the positioner. During testing of the machine some important observations like number of fruits harvested / h, weight of fruit harvested / h, average stem length (mm), visible damage (%), physiological loss of weight (%),shelf life of fruits (days) etc. were recorded.The cost of harvesting was determined out considering the prevailing rates of the tractor and labour during the season. Two workers,one for picking the fruits and another to receive the harvested fruits,were required for the operation.The experienced worker is engaged in picking the fruits and was paid better than the less experienced worker. The same workers were used to harvest the fruits using the developed machine.In order to estimate physiological loss in weight (PLW) of the harvested fruits two plastic trays lined with newspapers, were kept on the table at room temperature (20) and the harvested fruits were arranged in these trays in line keeping the stem end upward. The weight of the fruits was recorded every three days. On the 7th day, few fruits harvested using traditional picker showed symptoms of deterioration， are removed from the tray.Fig. 4 Fruit packet being taken from the positioner.Fig. 5 Operator picking coconut using positioneFig. 6 Fruits harvested using traditional mango picker.Fig. 7 Fruits harvested using developed positioner.Results and Discussion(i) Harvesting capacityThe results recorded during the trial of the machine are shown in Table 4. The average number of fruits harvested using the positioner were 360 per hour compared with local mango picker which can pick an average of 377 fruits per hour. Thus, using the positioner the harvesting capacity of the operator was slightly reduced. Considering that in raising / lowering and shifting the positioner took more time. Similar results were reported by Schertz (1967). During his study he observed that an operator standing on the ground was more efficient than harvesting the fruits from a ladder / positioner.(ii) Stem length The stem length is one of the most desirable parameter，The stem length of the stem fruits harvested using the positioner was within 20 mm. and uniform while in fruits harvested with traditional picker, had stems more than 50 mm and non-uniform. A number of fruits were harvested without stem, which is not desirable from the quality point of view. Such fruits do not have good appearance and a mango grower has to sell them at lower prices in the market. Moreover, it has been reported that fruits harvested without stem are subject to the occurrence of stem end rot disease. Fruits with stems recorded delayed ripening. It is necessary that the fruits should have stems ranging from 10 to 20 mm.(iii) Visible damageVisible damage on the fruit was observed in the form of sap burns. The fruits harvested without stem had sap bums. Such type of damage was almost nil in fruits harvested using the positioner because all the fruits had stem while the fruits picked using the traditional picker shows 11.11% visible damage.(iv) Shelf life of fruitsThis refers to the life of fruits in days for which they can be stored after harvesting without sustaining spoilage. The shelf life is affected by the harvesting methods. Fruits harvested using the positioner could be stored for 9 days without showing symptoms of spoilage. The appearance of the fruits was good and had attractive color. In comparison, those harvested using the traditional picker should dark spots on the body on the 7th day from the date of harvesting. If the fruit is physically damaged or injured the respiration rate of the fruit is increased and it is prone to microbial attack hence, during handling of the mango fruit, care taken to avoid any kind of injury and increase the shelf life of the fruits.(v) Cost of harvestingAs indicated in the Table 4 the cost of harvesting for using the positioner was Rs. 2783 / tonne of mango fruit as compared to Rs. 368 / tonne using the traditional picker. Thus, the cost of operation for the former was high but the quality of harvested fruit was very good and not a single fruit was lost by way of spoilage or decay while 10 -15%fruit loss was observed in case of traditional picker. Hence, considering 10% loss out of every 1000 kg. only 900 kg. of fruits were available for sale. That too at lower rate (Rs. 17.50 / kg) amounting Rs. 15,750. The fruit harvested using the positioner could be sold at higher price (Rs. 20 / kg.) amounting Rs. 20,000, thus gaining Rs. 4,250 more as compared to using the local picker. Subtracting the extra operating cost required in the case of the positioner i.e., Rs. 2,415 a net profit of Rs. 1835 / tonne could be harvested by a mango grower. In other words, about Rs. 900 / tree can be saved by adopting the developed positioner for harvesting of mango.(vi) Physiological loss in weightObservations regarding the physiological loss in weight (PLW) were also recorded every three days in the laboratory for each method of fruit harvesting in percentage and presented in Table 5. The PLW was higher on 3rd, 6th and 9th day for the fruits picked using the traditional mango picker. The total PLW was 13.27% and 15.88% for fruit harvested with the positioner and traditional picker, respectively.Fig. 8 Tractor mounted positioner.ConclusionsFrom the study following conclusions can be drawn:Using the positioner, mangoes without any mechanical injury are picked and only matured fruits are harvested as operation is conducted at a close distance.As 100 percent fruits are harvested with stems (1-2 cm), no sap bums were found and white layer (bloom) on the fruit is also maintained.Loss of fruit during storage and transportation is minimized.Due to high quality of fruit maintained during harvesting an fruit grower can harvest a net sum of Rs. 1000 per tree in a good season.REFERENCESAnnual report, 2000. Research, Testing and Training Centre, Gujarat Agricultural university, Junagadh Campus, Gujarat.Brown and Schertz, 1967. Principles and practices for harvesting and handling of fruits and nuts, vol.Data book (1992-99). Director of Horticulture, Gujarat State, Ahmedabad. Bulletin No. 20 / 2000 p. 8.Devnani, R.S. 1980. Harvesting equipments developed in India. Technical bulletin No. CIAE / 78 / 8，CIAE, Bhopal SapovadiaB.D., Patel H.N., Gupta R.A. and Pund S.K., 2001. Design and development of mango harvesting device. AMA30(l): 31-34. XXX設(shè)計(jì)(XXX)外文資料翻譯院 系專業(yè)學(xué)生姓名班級(jí)學(xué)號(hào)外文出處AGRICULTURAL MECHANIZATION ASIA，AFRICA AND LATIN AMERICA 2004 VOL.35 NO.1指導(dǎo)教師評(píng)語(yǔ)：指導(dǎo)教師簽名： 年 月 日附錄C：外文翻譯用于芒果收獲的變位機(jī)的發(fā)展和測(cè)試R.A.Gupta R.M.Satasiya Pramod Mohnot N.K.Gontia摘要為了減少在收獲芒果時(shí)的損失，并保證水果質(zhì)量，一種機(jī)掛式變位機(jī)在Gujiarant農(nóng)業(yè)大學(xué)被研制出來(lái)，并進(jìn)行了測(cè)試。在操作過(guò)程中發(fā)現(xiàn)，由變位機(jī)采下的芒果都是成熟的，而且有1020mm長(zhǎng)的葉柄，沒(méi)有樹(shù)葉粘在水果表面，且沒(méi)有任何損傷。在果園中用變位機(jī)，收獲時(shí)每棵樹(shù)可以節(jié)省RS1000。引言芒果是水果之王，在水果商業(yè)中有著重要的地位。印度是最大的芒果生產(chǎn)國(guó)和出口國(guó)。在Gujiarat，每年有57000公頃的芒果種植面積，生產(chǎn)大約382000噸的芒果。近來(lái)出口和種植的優(yōu)良品種遍布全國(guó)，主要集中在Gujiarat的南部和Saurashtra地區(qū)。水果的質(zhì)量主要取決于它的成熟期。在印度，收割芒果大多由手工完成。主要的工具就是鐮刀、剪刀、刀片和吊籃。就采芒果來(lái)說(shuō)，利用一些輕巧機(jī)械比用手采摘或搖樹(shù)的方法可降低勞動(dòng)強(qiáng)度。這樣還可以避免果實(shí)的損傷、樹(shù)枝折斷等后果。果實(shí)碰傷和損壞是非常嚴(yán)重的問(wèn)題。果實(shí)不允許直接從樹(shù)上摔到地上，因?yàn)樵诎b水果時(shí)，受傷的水果會(huì)損害其他好的水果。芒果釆摘時(shí)留有810mm的葉柄，是為了在采的時(shí)候避免樹(shù)汁留在芒果表面而形成污點(diǎn)，這樣水果就不容易腐蝕，也就避免產(chǎn)生其它保存問(wèn)題。Assam研究采摘水果的設(shè)備，人工操作的裝置都是用鐮刀或刀片將水果一個(gè)一個(gè)釆摘后再包裝，這樣的裝置適合大小和高度差不多的水果。另一種機(jī)械是搖樹(shù)裝置，這種裝置適合比較硬的水果。Brown和Schertz也在研究這種機(jī)械采摘裝置，并且曾宣布說(shuō)用該裝置采摘的水果比人工采摘的水果有更多的損傷，如裂開(kāi)、表面和內(nèi)部碰傷、表面創(chuàng)傷等。Gujarat農(nóng)業(yè)大學(xué)發(fā)明出一種先進(jìn)的釆摘裝置。跟其它采摘裝置相比，它有一個(gè)較好的工作情況。采下的水果大約有90%帶有1020mm長(zhǎng)的葉柄，特別符合出口要求。人工釆摘水果的時(shí)候利用一種輔助的機(jī)械變位機(jī)，可以讓人站在上面用剪刀采摘。因?yàn)椴裴娬獣r(shí)離水果較近，可以采那些成熟的水果而不讓其受傷害。因此機(jī)掛式液壓變位機(jī)的發(fā)展和測(cè)試是必要的。取材和方法機(jī)器初步信息的設(shè)計(jì)主要與樹(shù)的特征有關(guān)，要確保及其在果園里有足夠的活動(dòng)空間和能力。樹(shù)上的水果是分散的，可以采到的水果百分率見(jiàn)表1到3。機(jī)器的高度和底盤的尺寸也要仔細(xì)考慮。利用以上的信息，設(shè)計(jì)和發(fā)明的液壓變位機(jī)可以用來(lái)采芒果和其他水果。同樣也要考慮安全因素。要想減少機(jī)器的花費(fèi)，可以通過(guò)減少移動(dòng)部分的數(shù)量來(lái)實(shí)現(xiàn)。機(jī)器主要由一個(gè)底盤、三點(diǎn)懸掛裝置、液壓千斤頂和護(hù)圈組成。底座由50*50*6的角鋼制成，機(jī)座的組成及尺寸見(jiàn)圖1?？沙惺?噸重的液壓千斤頂有兩個(gè)氣缸，通過(guò)40mm長(zhǎng)的銷安裝在機(jī)座的中心，并通過(guò)兩塊金屬板焊接在機(jī)座和液壓千斤頂下端。液壓千斤頂上面的一端由三根支撐桿支撐著。類似的，活塞的上端通過(guò)螺母和螺栓固定在法蘭盤上。為了使變位機(jī)的高度可調(diào)，就要將1mm長(zhǎng)的、可伸長(zhǎng)的100mm的軟管用法蘭盤、螺母、螺栓連接在活塞的上端。管子上端通過(guò)相同尺寸（20*20cm)的法蘭盤焊接在防護(hù)罩上。防護(hù)罩由角鋼、可鑄鋼板和木板構(gòu)成。機(jī)座的護(hù)圈由角鋼制成，尺寸為92*76*70cm。防護(hù)圈的底座由木板支撐。底部的一邊由一個(gè)55*47cm的開(kāi)口，可以使采摘者站到變位機(jī)上。變位機(jī)上四邊是可以折疊的，當(dāng)機(jī)器移動(dòng)時(shí)，其高度可以調(diào)節(jié)到最低。要操作該機(jī)械裝置，要通過(guò)液壓千斤頂?shù)娜c(diǎn)聯(lián)動(dòng)裝置和軟管連接到液壓系統(tǒng)的牽引機(jī)上。防護(hù)罩升至伸長(zhǎng)部分的頂部，四邊折疊。機(jī)械裝置被運(yùn)送到指定果園，在釆摘的時(shí)候，裝置要放在地上，釆摘者帶剪刀和紙箱站在防護(hù)罩下的地板上。為了安全起見(jiàn)，防護(hù)罩的四邊都應(yīng)該有護(hù)欄，由鉤銷鉸接在機(jī)座上。牽引機(jī)的液壓系統(tǒng)舉起防護(hù)罩，一旦閥打開(kāi)，油在壓力作用下由軟管進(jìn)入千斤頂，推動(dòng)千斤頂?shù)幕钊?，從而使防護(hù)罩上升。當(dāng)達(dá)到所需要的高度，關(guān)閉閥，使其停止上升。采摘者可以在很近的距離內(nèi)采水果。只采那些成熟的水果放入紙箱內(nèi)。當(dāng)紙箱裝滿時(shí)，可以將其送到地上。一些水果長(zhǎng)在樹(shù)頂上，采摘者可以用手工采摘工具。 圖2.變位機(jī)的動(dòng)力來(lái)源圖3.使用者用變位機(jī)采摘芒果測(cè)試果樹(shù)以12*12m的距離種植。用35馬力的HMT牽引機(jī)來(lái)做實(shí)驗(yàn)。有經(jīng)驗(yàn)的工作人員可以站在上面釆水果。在機(jī)械裝置的測(cè)試期間，一些重要的觀察，比如每小時(shí)采摘水果的數(shù)量、質(zhì)量、葉柄平均長(zhǎng)度、明顯損害率、水果的保存期限等。采摘的費(fèi)用主要由勞動(dòng)力等。該裝置需要兩個(gè)工作人員，一個(gè)采一個(gè)接。老練的工人得到的報(bào)酬比經(jīng)驗(yàn)少的工人多。為了估計(jì)水果質(zhì)量的損失，將兩個(gè)塑料袋放在室溫條件下，將采下的水果按葉柄排放整齊，每隔三天紀(jì)錄一下。第七天，用傳統(tǒng)方法采下的水果有變質(zhì)的征兆，將它們從袋中取出。結(jié)果與討論 1、收割量機(jī)器試用所記錄的結(jié)果見(jiàn)表4。用變位機(jī)平均每小時(shí)可采水果 360個(gè)，而當(dāng)?shù)氐尼娬呙啃r(shí)可采377個(gè)。因?yàn)樽兾粰C(jī)的上升和下降都需要時(shí)間，在1967年，Schertz也報(bào)道過(guò)相似的結(jié)果。在研究過(guò)程中，他發(fā)現(xiàn)站在地上采水果的效率要比站在變位機(jī)上的效率高。2、葉柄長(zhǎng)度葉柄地起限定作用的一個(gè)因素。用變位機(jī)采下的水果，其葉柄一般長(zhǎng)20cm,而用傳統(tǒng)方法采下的水果，其葉柄長(zhǎng)度一般不一樣，有的甚至超過(guò)50cm，但有的卻又沒(méi)有葉柄。這些水果的賣相不好，果農(nóng)必須以低價(jià)才能出售。此外，研究表明沒(méi)有葉柄的水果會(huì)使柄末端發(fā)生腐爛，而有柄的水果會(huì)延長(zhǎng)它的成熟期。所以使水果有1020cm 的葉柄是必要的。3、表面損傷水果表面損傷是由樹(shù)枝造成的，這種損傷在用變位機(jī)采下的水果上是沒(méi)有的，因?yàn)樗械乃加腥~柄。而用傳統(tǒng)方法采下的水果11.11%有表面損傷。4、水果的存放期這個(gè)涉及到采下的水果在沒(méi)有任何持續(xù)損害的情況下可以被存放的期限。保存的期限與采摘的方法有關(guān)。用變位機(jī)采下的水果可以完好無(wú)損的保存9天，水果仍然有完好的表面和誘人的顏色。而用傳統(tǒng)方法采下的水果在第七天會(huì)出現(xiàn)黑的斑點(diǎn)。如果水果受到傷害或呼吸作用受到限制，微生物很容易侵入水果內(nèi)部，所以應(yīng)該細(xì)心的避免各種傷害，延長(zhǎng)水果的保存期限。 表4.比較用不同方法采摘的水果的測(cè)試5、釆摘的成本表4表明，用變位機(jī)的采摘成本為每噸RS2783，而用傳統(tǒng)方法采摘的成本大約每噸RS368。前者的成本雖然高，但水果質(zhì)量好，沒(méi)有一個(gè)會(huì)因?yàn)閾p害或腐爛而造成損失，而后者雖然成本低，但一般都有1015%的損失率。由于10%的損失相當(dāng)于1000kg最終只有900kg可以賣，如果每千克以RS17.50出售，可以得到RS15750。而用變位機(jī)采下的水果可以高價(jià)出售，每千克可賣到RS20，共可以得到RS20000，扣除所需要的操作費(fèi)用RS2415，所得到的利潤(rùn)為RS1835/噸。換句話說(shuō)，釆用變位機(jī)采水果，每棵樹(shù)可以節(jié)省RS900。6、質(zhì)量的減少關(guān)于對(duì)plw的觀察，在實(shí)驗(yàn)室每隔三天的記錄見(jiàn)表5。采用傳統(tǒng)方法采摘的水果在第3天、第6天、第9天其質(zhì)量逐漸減輕，其損失率為15.88%，而采用變位機(jī)的損失率為13.27%。表5.水果質(zhì)量的損失結(jié)論從以上的研究中我們可以得出以下結(jié)論：1、利用變位機(jī)采下的水果沒(méi)有機(jī)械損傷，而且都是熟的。2、采下的水果100%的都有l(wèi)2cm的葉柄，沒(méi)有樹(shù)葉，并且保持白色的亮度。3、存放和運(yùn)輸?shù)膿p失可以減到最低程度。4、由于釆下的水果質(zhì)量較好，每棵樹(shù)的凈利潤(rùn)為RS1000。參考文獻(xiàn)1.Annul report,2000.Research, Testing and Training Centre, Gujarat Agricultural university, Junagadh Campus, Gujarat2.Brown and Schertz, 1967. Principles and practices for harvesting and handling of fruits and nuts, vol.3.Data book(1992-99). Director of Horticulture, Gujarat state,Ahmedabad. Bulletin No. 20/2000p. 8.4.Devnani,R.S.1980. Harvesting equipments developed in India. Technical bulletin No. CLAE/78/8, CLAE, Bhopal.5.Sapovadia B. D., Patel H.N.,Gupta R. A.and Pund S.K.,2001. Design and development of mango harvesting device.AMA 30(1):31-34.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 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 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 positioner 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 of 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 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 attached 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 damage 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 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 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 mechanically 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 better 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 positioner 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 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 and 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 factors 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 size. The dimensions and structural members of the frame are shown in the Fig. 1. A hydraulic jack of 2 tonnes capacity with two cylinders is mounted at the centre of the frame with the help of a pin of 40 mm passing through two plates welded to the frame and lower end of the hydraulic jack. The upper end of the jack is supported by fastening three supports to the frame and upper end of the jack. Similarly, the upper end of the piston is fastened to a flange through nuts and bolts. To extend the height of the positioner an extension pipe of 100 mm and 1 m length is attached to the upper end of the piston through flange, nuts and bolts. On the upper end of the extension pipe another flange of the same size (20 20) cm is welded on which cage is fixed through nuts and bolts. The cage of machine is fabricated from angle iron, mild steel flat and wood. The frame of the cage is made out of angle iron. The size of the cage is (92 76 70) cm. At the bottom of the cage, wooden plank is provided. On one side of the bottom an opening of (55 47) cm size is provided through which an operator can get on the positioner to pick up the mature fruits. All the four sides of the positioner are kept folding so that when the machine is on transport from one place to another the sides can be lowered to keep the height minimum.To operate the machine, it is hitched to a tractor through three point linkages and hosepipe of the hydraulic jack is connected to the hydraulic system of the tractor. The cage is mounted on top of the ex- tens4n piece and its sides are folded. The machine is transported to the orchard where mango picking is to be done. During operation, the machine is placed on ground and operator gets on the cage along with a pair of scissor and carton through the opening provided at the bottom of the cage. All the sides of the cage are kept in upright position and hinged to the frame through hooks pins for safety point of view. The hydraulic system of the tractor is operated to lift the cage. As soon as the valve is opened, the oil under pressure goes to jack through hosepipe, which lifts the piston of the jack, thus, the cage is lifted. When required height is reached, valve is closed to stop further upward movement of the cage. Then, the operator pick the fruits from a very close distance using a pair of scissors / secateure. Only matured fruits are picked and kept in the carton.When the carton is full of fruits it is packed and taken on the ground. The machine is taken around the tree to pickup matured fruits. Some of the fruitswhich are located on the top of the tree, are beyond the reach of the operator, are picked using manually operated mango picker. Fig. 1 Tractor-mounted positioner for harvesting mango. Fig. 2 Positioner attached with power Fig. 3 Operator picking mango using positioner.TestingA field testing of the machine was conducted at the Sagdividi farm of Gujarat Agricultural University, Junagadh campus for the Kesar variety of mango which is very popular among in the Saurashtra region of Gujarat state. Thetrees were planted at (12 X 12)m distance. HMT zetor tractor of 35 hp was used to operate the machine. An experienced worker was engaged to pick the fruits in standing posture on the positioner. During testing of the machine some important observations like number of fruits harvested / h, weight of fruit harvested / h, average stem length (mm), visible damage (%), physiological loss of weight (%),shelf life of fruits (days) etc. were recorded.The cost of harvesting was determined out considering the prevailing rates of the tractor and labour during the season. Two workers,one for picking the fruits and another to receive the harvested fruits,were required for the operation.The experienced worker is engaged in picking the fruits and was paid better than the less experienced worker. The same workers were used to harvest the fruits using the developed machine.In order to estimate physiological loss in weight (PLW) of the harvested fruits two plastic trays lined with newspapers, were kept on the table at room temperature (20) and the harvested fruits were arranged in these trays in line keeping the stem end upward. The weight of the fruits was recorded every three days. On the 7th day, few fruits harvested using traditional picker showed symptoms of deterioration， are removed from the tray.Fig. 4 Fruit packet being taken from the positioner.Fig. 5 Operator picking coconut using positioneFig. 6 Fruits harvested using traditional mango picker.Fig. 7 Fruits harvested using developed positioner.Results and Discussion(i) Harvesting capacityThe results recorded during the trial of the machine are shown in Table 4. The average number of fruits harvested using the positioner were 360 per hour compared with local mango picker which can pick an average of 377 fruits per hour. Thus, using the positioner the harvesting capacity of the operator was slightly reduced. Considering that in raising / lowering and shifting the positioner took more time. Similar results were reported by Schertz (1967). During his study he observed that an operator standing on the ground was more efficient than harvesting the fruits from a ladder / positioner.(ii) Stem length The stem length is one of the most desirable parameter，The stem length of the stem fruits harvested using the positioner was within 20 mm. and uniform while in fruits harvested with traditional picker, had stems more than 50 mm and non-uniform. A number of fruits were harvested without stem, which is not desirable from the quality point of view. Such fruits do not have good appearance and a mango grower has to sell them at lower prices in the market. Moreover, it has been reported that fruits harvested without stem are subject to the occurrence of stem end rot disease. Fruits with stems recorded delayed ripening. It is necessary that the fruits should have stems ranging from 10 to 20 mm.(iii)Visible damageVisible damage on the fruit was observed in the form of sap burns. The fruits harvested without stem had sap bums. Such type of damage was almost nil in fruits harvested using the positioner because all the fruits had stem while the fruits picked using the traditional picker shows 11.11% visible damage.(iv)Shelf life of fruitsThis refers to the life of fruits in days for which they can be stored after harvesting without sustaining spoilage. The shelf life is affected by the harvesting methods. Fruits harvested using the positioner could be stored for 9 days without showing symptoms of spoilage. The appearance of the fruits was good and had attractive color. In comparison, those harvested using the traditional picker should dark spots on the body on the 7th day from the date of harvesting. If the fruit is physically damaged or injured the respiration rate of the fruit is increased and it is prone to microbial attack hence, during handling of the mango fruit, care taken to avoid any kind of injury and increase the shelf life of the fruits.(v)Cost of harvestingAs indicated in the Table 4 the cost of harvesting for using the positioner was Rs. 2783 / tonne of mango fruit as compared to Rs. 368 / tonne using the traditional picker. Thus, the cost of operation for the former was high but the quality of harvested fruit was very good and not a single fruit was lost by way of spoilage or decay while 10 -15%fruit loss was observed in case of traditional picker. Hence, considering 10% loss out of every 1000 kg. only 900 kg. of fruits were available for sale. That too at lower rate (Rs. 17.50 / kg) amounting Rs. 15,750. The fruit harvested using the positioner could be sold at higher price (Rs. 20 / kg.) amounting Rs. 20,000, thus gaining Rs. 4,250 more as compared to using the local picker. Subtracting the extra operating cost required in the case of the positioner i.e., Rs. 2,415 a net profit of Rs. 1835 / tonne could be harvested by a mango grower. In other words, about Rs. 900 / tree can be saved by adopting the developed positioner for harvesting of mango.(vi) Physiological loss in weightObservations regarding the physiological loss in weight (PLW) were also recorded every three days in the laboratory for each method of fruit harvesting in percentage and presented in Table 5. The PLW was higher on 3rd, 6th and 9th day for the fruits picked using the traditional mango picker. The total PLW was 13.27% and 15.88% for fruit harvested with the positioner and traditional picker, respectively.Fig. 8 Tractor mounted positioner.ConclusionsFrom the study following conclusions can be drawn:Using the positioner, mangoes without any mechanical injury are picked and only matured fruits are harvested as operation is conducted at a close distance.As 100 percent fruits are harvested with stems (1-2 cm), no sap bums were found and white layer (bloom) on the fruit is also maintained.Loss of fruit during storage and transportation is minimized.Due to high quality of fruit maintained during harvesting an fruit grower can harvest a net sum of Rs. 1000 per tree in a good season.REFERENCESAnnual report, 2000. Research, Testing and Training Centre, Gujarat Agricultural university, Junagadh Campus, Gujarat.Brown and Schertz, 1967. Principles and practices for harvesting and handling of fruits and nuts, vol.Data book (1992-99). Director of Horticulture, Gujarat State, Ahmedabad. Bulletin No. 20 / 2000 p. 8.Devnani, R.S. 1980. Harvesting equipments developed in India. Technical bulletin No. CIAE / 78 / 8，CIAE, Bhopal SapovadiaB.D., Patel H.N., Gupta R.A. and Pund S.K., 2001. Design and development of mango harvesting device. AMA30(l): 31-34.