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Design principle and analyses of the motion characteristics of 4H-2 type peanut harvesterCollection of Extent Abstracts of 2004 CIGR International Conference(Volume.2) 2004.Shuqi Shang;Professor;Head of Engineering School;Laiyang Agricultural College;Shandong 265200;China Fangyan WangEngineering School of Laiyang Agricultural College (Shandong 265200;China) Shuguang LiuEngineering School of Laiyang Agricultural College (Shandong 265200;China)AbstractThe structure, working principle and design of main parts of the 4H-2 type peanut harvester were described and analyzed, and the kinematics model of the main work parts was founded. On the basis of the optimized structure, the representative tracks of the work parts were described by means of Visual Basic and SPSS software and the machine function characteristics. The theoretical foundation has been provided for further study of this kind of machines.Key words: Peanut harvester; design principle; motion characteristics1IntroductionThe peanut is one of the main oil plants in the world, which is only inferior to soybean but ranks the second for oil production and international trade1,2. For a long time, the planting, harvesting and processing of peanut were mostly completed by manual work. It is a piece of labored work with low efficiency, which affects the peanut production seriously. Especially in the last few years, as the transferring surplus rural labors to urban areas, the contradiction of each link of peanut production is more intensifying, the mechanization of the peanut production becomes particularly important.It has been a long time for researching and developing the peanut harvesters in developed countries, it is a typical representative that the LP-2 type peanut harvester and peanut combine harvester of Courtesy lf Lilli ston Mfg. Co. in the United States and PH-2 type peanut harvester of Michigan in Netherlands3. The development of peanut harvester in China is later than that in developed countries, perhaps the beginning of the 1960s. Since the 1970s, many representative mimic peanut harvesters were introduced into China such as the Dongfeng 69 type, 4HW-800 type and 4H-150 type peanut harvester etc.4. These products bring convenience for harvesting peanut, but the structure of all current harvesters adopted the two steps of harvest principlescoop and separating chain combine together. These machines have to match with the medium-big power tractors. It is not only complex in structure, higher manufacturing costs, more power consumption, poor reliability, but also higher harvesting loss rate, peanut vines spread disorderly, and inconvenient for manual collection. It is not suitable for the current requirement of peanut harvesting and results in that the harvesting of peanut is almost completed by manual work at present. The mechanization level of peanut harvesting affected the development of the peanut production seriously.With the environment deterioration, at sowing-season in spring or autumn, the phenomenon of dry and little rainfall appears. The peanut production suffered from the weather. It had led to adopting technique of plastic film covering(Figure 1 shows its section structure). This new technique will play an important role in keeping the moisture of soil, increasing ground temperature, and reducing management in seedling period, and then increasing the output of peanut. The peanut seeding-machine with many functions has already applied in large-scale areas, but the quantity of the film remains is increased, which influences the following work5-9.Fig.1Profile of peanut covering plastic film and seeding beds8For solving the problems mentioned above, a new type of peanut harvester with new working principle and structure was invented, which has already come to the market. The harvester has already acquired the petty patent now (patent number: ZL 01221476.0), and patent for invention ( patent number: 99124518.0) has been investigating in substance.2Structure design of the peanut harvester2.1Analysis of the whole machine structure4H-2 type peanut harvester combines with the advanced method of planting and agricultural requirement, which can harvest two rows at one working stroke. It matches with the 8.813.0 kW small four-wheel tractors. 4H-2 type peanut harvester is composed of gaging wheel, transmission shaft, eccentric wheel, pitman, long rocker-arm, erect axis, harvesting parts, long pitman, rocker-arm, mounting device and frame etc. The figure 2 shows its structure.1.gaging wheel2.joint coupling3.transmission shaft4.erect axis5.long rocker-arm6.long pitman7.mounting device 8.rocker-arm9.erect axis10.harvester part11.eccentric wheel12.pitman13.harvest part14.frameFig.2Diagram of peanut harvesterThe driving power needed of the work parts of 4H-2 type peanut harvester comes from the PTO of tractor. When the machine with tractor goes forward, the PTO drives eccentric wheel 11 pass through joint coupling 2 and transmission shaft 3. Then eccentric wheel 11 drives long rocker-arm 5 to move pass through pitman 12. As erect axis 4 and harvest parts 13 are made together, rocker 8 with long pitman 6 and long rocker-arm 5 constitute an inverse parallelogram mechanism, therefore harvest parts 10 and 13 swing with erect axis 4 and 9 with the same frequency and angle but contrary direction. The working process is: the scoops 10 and 13 digging the peanut out andmoving the peanut backward, while the lengthways grids continuously make the fanlike swing, and then break the admixture of soil and peanuts. By this movement the heavy soil sinks down via the grids, and the lighter peanut moves up, so that peanut is separated from soil well. The peanut is moving rearward continuously, finally even laying on the excavated ground, so it is convenient for manual collection.2.2Main technique parametersThe table 1 shows the main technique parameters of 4H-2 type peanut harvester.Table 1Main technique parametersPower requirement8.813.0 kW small four-wheeled tractorProductivity/hm2h-10.100.13Losing rate of nuts2%Containing rate of soil in peanut(by quantity calculation)5%Broken rate of nuts1%Picked rate of nuts by mechanisms3.5%Overall size (LWH mm)/mm31280l180780Net weight/kg 1583Design of main working parts3.1Design of the transmission partsFor overcoming the weakness of the traditional peanut harvesters mentioned in this paper, the 4H-2 type peanut harvester has been invented with a new structure and principle. Its scoops and separating parts have been combined together that can reduce the power consumption, the size of the machine and harvesting loss. The transmission and control devices are designed for transmitting power efficiently and adjust conveniently. In order to match the tractor of 8.8 kW, the power input shaft 1 of 4H-2 type peanut harvester is located in flank of left. The inverse parallelogram mechanism is the remarkable characteristics of this machine. It swings both scoops with the same angle but opposite direction. The side forces acted on two scoop frames are balanced each other. The stability of the machine is ensured and the investment of manufacturing is reduced greatly, which is benefited to large-scale production and popularization of the harvesters.3.2Design of scoop framesWhen the harvester working in field with dense peanut stalks, the flowing channel of the peanut is easily jammed, resulting in that the working resistance is increasing, and peanut separating is ineffective, even the harvester cannot continue to work. For resolving this problem, the structure of half open arm has been created for the scoop frame (show in the figure 3) and the bottom is the scoop. As there are tow scoops, the form respectively is and , tow of them forming the channel, which makes the peanut stalks easily to pass it.Fig.3Diagram of scoop frames3.3Design of the transmission with V-beltAccording to the different circumstances of the fields, the swing frequency of harvesting parts should be adjusted and changed. For this reason, the one step V-belt transmission has been adopted for changing the swing frequency by replacing the V-belt pulleys. After optimizing the four-bar linkage and the size of the belt pulleys, the frequencies and the range of swing are more reasonable.3.4Design of the grid shapeIf the sectional shape of grid is round, the connection point of grids with scoop will be broken easily after working. In order to increase its anti-bent intensity, the flat rectangle sectional grids have been selected out and application after making theoretical design and experimental analysis (the figure 4 shows its structure). Fig.4Diagram of grid shape4Equation of kinematics 4.1Theoretical analysis of the main partsFigure 5 shows the structure of transmission parts of 4H-2 type peanut harvesters. In this figure, No.3 is transmission shaft and No.11 is eccentric wheel, the AE and BD respectively indicate the rocker-arm 5 and 8, the CD and EF indicate pitman 6 and 12 respectively, the A and B is respectively erect axes 4 and 9 (reference Figure 2). Fig.5Diagram of transmission parts structureFig.6Simplification diagram of movement9,10When 4H-2 type peanut harvester working, transmission shaft 3 drives eccentric wheel 11 running. As the track of point E is a space arc, but its length is far shorter than AE rocker s in XOY coordinate plane (10%), so that E point track may approximately be the straight line movement which is in the XOY coordinate plane. The figure 6 shows the movement form. OF stands for eccentricity and EF stands for pitman 12. As OF=R,EF=L, then the track of E point may approximate be considered a straight line OE. So the rectangular system of axis can be established to find the kinematics equation. Turn O to be the origin of coordinates, the direction of OO is the positive direction of X axes. According to the known condition, at beginning t= 0,F is in the place for F,E is in the place for O. Obviously OF+OF=L+R. At any time E point coordinates is:According to the crank rocker structure, K is usually among 1/61/4. By the binomial equation, thenAs the other numbers are much small from the third number, so all of them are ignored.Videlicet: , then E point kinematics equation approximately is: The motion characteristics of inverse parallelogram mechanism ABCD depends on the track of point E. The figure 7 shows the structure. A and B stand for erect axes 4 and 9 respectively, AE and BD are respectively rocker 5 and 8,CD is pitman 6. If A is at zero (0, 0). The direction of AX is the positive direction of polar axes.AE=L1. Then A (erect axis) angular velocity equation approximate is:Fig.7Schematic of inverse parallelogram mechanism4.2Kinematics equation of the harvest partsAs the figure 8 shows, when 4H-2 type peanut harvester is static to the ground relatively, any point of swing grid AH motion as horizontal and fan-shape reciprocating movement, around its erect axis. When working, the movement of any point of swing grid AH is composed of the swing motion of erect axis and moving of tractor. Because of the swing velocity of erect axis is different, the motion track is not the same, but there is certain regulation. Take the farthest point H of swing grid, its relatively static equation is:Its relatively kinematics equation is:On the basis of optimum parameter, the track of the farthest point H of swing grid has been gotten by making use of the Visual Basic and SPSS software (Shows in the figure 9).Fig.8Diagram of velocity synthesisFig.9Relatively kinematics track of H point5Function characteristics of the harvesterThe swing-digging principle and the inverse parallelogram mechanism have been successfully created and applied to 4H-2 type peanut harvester. It had broken the traditional way which is scoop and separate chain to combine together for harvesting.(1) 4H-2 type peanut harvester should be matched with the small four-wheel tractors which are very universal. Its design is reasonable, with reliable working, steady function, convenient adjustment, higher adaptability, and this machine can work in various fields and harvest all kinds of peanut.(2) The swing-digging principle had been created for merging scoop and separator together. That has successfully realized the work of digging and separating peanut by one set of part, and simplified the working procedure. The two harvest parts were used through inverse parallelogram mechanism to transfer power, turning them by the same angle for swing but opposite direction, making the two sides force acted on scoop frames balanced each other, the operation stability of it is ensured, the resistance and the power consumption have been reduced.(3) In harvesting process, plastic film was not broken and easy collected with the peanut stalks. There is none leavings of them on the ground.(4) As created the swing-digging principle, the whole resistance and the power consumption of the harvester have been reduced. By means of the swing function, the soil with heavy specific gravity sinking passes through the grids, and the peanut with lighter specific gravity moves up, so that the loss rate of peanut was reduced remarkably.(5) The various working and performance indexes of the machine are superior to the similar type of peanut harvesters, and productivity of it was higher, loss rate lower, the economic benefit remarkable.4H-2 type peanut harvester is the new typical agricultural implement for the small scale farms of China and more suitable for Chinese peanut production. This harvester has the simpler structure and lower price. Its various performance indexes are superior to the Standard of technique indexes for peanut harvesting in China. It can bring more economic benefit to the customers. After application and extension to peanut production, the 4H-2 type peanut harvesters have won broad praise from the society. This patent achievement indicates fully that the design and principle of 4H-2 type peanut harvesters has reached a new high level.References1Duan Shufen, Hou Wenguang. The world peanut production and the trade outlookJ. Chinese agriculture bulletin,1990,6(2):21-25.2Tao Shouxiang. The present condition and outlook of peanut high yield in Shandong provinceJ. Peanut science and technology,1993,2:26-29.3Chen Chuanqiang. The broadcast lecture of the mechanization of peanut technique productionR. The agriculture machinery extension center of Shandong province,2000.4Chinese agriculture movie &television center. How many peanut harvestersN. 2002-10-15.5The comprehensive mechanization technique of peanut production. The agricultural technique extension center of Shandong province,1999.6Hao Ming, et al. Peanut production machineryM. The publishing house of Hebei province,1981,81-90.7Hua Fagai. Cover-film-planting is the new path to boost peanut production N. Fujian agricultural technology, 2000,4:12-14.8Sun Yanhao. The peanut production & cultivation. The gold shield publishing house,1991,61-80.9Peanut Institute of Shandong province. Peanut M . Jinan: Science &Technique Publishing House of Shandong Province,1982,46-52.10 Nanjing engineering college & Xian transportation university. Theories of mechanics (the second version) M. Higher Education Publishing House, 1985, 112 - 210.4H-2型花生收获机的设计原理及运动特性分析摘要本文主要描述和分析了4H-2型花生收获机的结构、工作原理和主要部件的设计，并对其主要的工作部件建立了运动学模型。在结构最优化的基础上,利用VB编程和SPSS软件描绘出了工作部件的代表性轨迹;并简述了其性能特点,为今后同类型花生收获机的研究提供了理论基础。关键词：花生收获机；设计原理；运动特性1 引言花生是世界上的主要的油料植物，它仅次于大豆，并在油料生产和国际贸易中排名第二.长期以来，花生的种植、收获和加工绝大部分工作由手工作业完成，它是一种效率低下的工作，并且严重影响了花生的生产产量。尤其是近几年，随着农村剩余劳动力向城市地区的转移，花生生产中的各个环节的矛盾更加激化，在此过程中的机械化就显得尤为重要。在发达国家中对于花生收获机的研究和开发已有很长的时间了，典型的代表就是美国的LP- 2型花生收获机和Courtesy lf Lilli ston制造公司的花生联合收获机以及荷兰密歇根州的PH- 2型花生收获机。花生收获机在中国的发展要晚于发达国家，大致从 20世纪60年代开始。70年代以来，许多具有代表性的仿造的花生收获机被引进中国，如东风69型，4HW -800型和4H- 150型等。这些产品对于花生收获虽然带来了便利性，但目前所有收获机的结构均采用了两步收获方式，即挖掘铲与分离链相配合。这些机器必须配合大中马力的拖拉机。这样以来不仅结构复杂、制造成本较高、耗电多、可靠性差，而且造成很高的收获损失率，使花生藤蔓延无序，不方便手工收集。它不适合当代的花生收获要求，并导致了目前的花生收获几乎都是由手工作业完成。花生收获的机械化程度严重影响了花生生产的发展。随着环境的恶化，在春季或秋季的播种季节，出现了干旱或降雨量减少的现象。花生的生产受到了这种恶劣天气的影响，进而产生了采用塑料薄膜覆盖的技术（图1显示了其部分结构）。这种新技术在保持土壤水分，增加地面温度，减少幼苗期的管理，以及增加花生的产量方面都发挥了重要作用。多功能花生播种机在大片地区已经应用，随之薄膜的数量仍然增加，继而影响接下来的工作。图1 花生覆盖塑料薄膜和播种床的简介为了解决上面提到的问题，一种具有新型工作原理和结构的花生收获机已被发明，并且已经投入到了市场。该收获机现在已经取得了小型专利（专利号：ZL01221476.0），并且该专利（专利号：99124518.0）也基本上一直处在调查研究中。2 花生收获机的结构设计2.1 整机结构的分析4H-2型花生收获机结合了种植和农业需求的先进方法，在一个工作行程中它可以收获两行。它配备了8.813.0千瓦的小四轮拖拉机。4H-2型花生收获机是由量具轮、传动轴、偏心轮、连杆、长摇臂、直立轴、收获部分、长连杆、摇臂以及安装设备和机架等部分组成。图2展示了它的结构。1量具轮 2联轴器 3传动轴 4直立轴 5长摇臂 6长连杆 7安装装置 8摇臂 9直立轴 10收获机部分 11偏心轮 12连杆 13收获部分 14机架 图2 花生收获机示意图4H -2型花生收获机工作部件的驱动力来自于拖拉机的动力输出。当本机与拖拉机前进时，动力输出轴通过联轴器2和传动轴3驱动偏心轮11运动。然后，偏心轮11通过连杆12驱动长摇臂5运动。由于直立轴4和收获部分13做在一起，摇臂8和长连杆6及长摇臂5构成反平行四边形机构，因此收获部分10和13随着直立轴4和9以相同的频率和角度但相反的方向摆动。其工作过程是：挖掘铲10和13挖出花生并使其向后移动，而纵向网格连续做摆动，迫使土壤和花生分开。通过这种运动，重的土壤通过网格沉落，而较轻的花生向上移动，从而使花生与土壤分离良好。花生不断向后移动，最后平铺在挖开的地上，这样就可以方便人工收集了。表1展示了4H-2型花生收获机的主要技术参数。 表1主要技术参数功率要求8.813.0千瓦小四轮拖拉机生产力/万株每小时0.100.13花生损失率2土壤中花生含有率（按数量计算）5花生破碎率1花生拾取率3.5外形尺寸（长宽高mm）/ mm31280L180780净重/千克1583 主要工作部件的设计 3.1 机械传动部件的设计 为了克服在本文中提到的传统花生收获机的缺点，一种具有新型结构和工作原理的4H-2型花生收获机已被发明。它的挖掘铲和分离部分结合在一起，能够降低能量消耗、设备的大小和收获损失。它的传动与控制机构是为高效率传送功率和方便调整而设计的。为了匹配8.8千瓦的拖拉机，4H-2型花生收获机的动力输入轴1位于左侧侧翼。反平行四边形机构是本机的显着特点，它使挖掘铲同角度反方向的摆动。两个挖掘铲所产生的侧向力互相平衡，这样机器的稳定性得到了保证，收获机大规模的生产与广泛的普及将使生产的投资也大为减少。3.2 挖掘铲机架的设计当收获机在稠密花生地工作时，花生的运送通道很容易被轻易卡住，导致工作阻力增加，花生分离效果欠佳，甚至是收获机无法继续工作。为了解决这个问题，半开放机械臂已为挖掘铲机架而设计（如图3所示），其底部就是挖掘铲。正因为它有两个挖掘铲，它的形式分别是什么和什么，形成了运送通道，这就使得花生秸秆很容易通过。图3 挖掘铲机架示意图3.3 V形皮带传送的设计根据不同情况的土地，应该调整和改变收获部分的摆动频率。出于这个原因，通过替换V型皮带轮而改变摆动频率的V型带传送机构已被采用。在优化四连杆机构和皮带轮的大小之后，摆动的频率和范围更加合理。3.4 网格状的设计如果网格的截面形状为圆形，那么和挖掘铲的连接点