Design principle and analyses of the motioncharacteristics of4H-2type peanut harvesterShang Shuqi,Wang Jiangang,Wang Fangyan,Liu Shuguang,Jiang Yuanzhi (EngineeringSchool,LaiyangAgricultural University,Laiyang,Shandong265200,China) Abstract: The structure, working principle and design of main parts of the 4H-2 type peanut harvester were described andanalyzed, and the kinematics model of the main work parts was founded. On the basis of the optimized structure, therepresentative tracks of the work parts were described by means of Visual Basic and SPSS software and the machinefunction characteristics. The theoretical foundation has been provided for further study of this kind of machines.Key words: Peanut harvester; design principle; motion characteristicsCLC number: S225.73 Document Code: A Article ID:1002-6819(2005)01-0087-051 IntroductionThe 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 trade.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 Netherlands. 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.These products bring convenience for harvesting peanut, but the structure of all current harvesters adopted the two steps of harvest principle—scoop 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.2 Structure design of the peanut harvesterAnalysis 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 8.8~13.0 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.erectaxis5.long rocker-arm6.long pitman7.mounting device8.rocker-arm9.erect axis 10.harvester part 11.eccentricwheel 12.pitman 13.harvest part 14.frameFig.2 Diagram 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 and moving 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.3：Function 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) In harvesting process, plastic film was not broken and easy collected with the peanut stalks. There is none leavings of them on the ground.(3) 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.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.References[1] Duan Shufen, Hou Wenguang. The world peanut production and the trade outlook[J]. Chinese agriculture bulletin,1990,6(2):21-25.[2] Tao Shouxiang. The present condition and outlook of peanut high yield in Shandong province[J]. Peanut science and technology,1993,2:26-29.[3] Chen Chuanqiang. The broadcast lecture of the mechanization of peanut technique production[R]. The agriculture machinery extension center of Shandong province,2000.[4] The comprehensive mechanization technique of peanut production. The agricultural technique extension center of Shandong province,1999.[5] Zhao Ming, et al. Peanut production machinery[M]. The publishing house of Hebei province,1981,81-90.[6] Sun Yanhao. The peanut production & cultivation. The gold shield publishing house,1991,61-80.[7] Peanut Institute of Shandong province. Peanut [ M ]. Jinan: Science &Technique Publishing House of Shandong Province,1982,46-52.4H-2型花生收获机的设计原理及运动特性分析尚书旗，王方艳，刘曙光，赵忠海，王建春摘要:通过对国内外花生收获机械的调研与资料检索,综述了用于分段收获的花生挖掘犁、花生收获机和用于联合收获的花生联合收获机的类型及特点。