In order to solve the problems of large loss rate and high damage rate of 4UZL-1 sweet potato combine harvesters during the operation process, the working principle of 4UZL-1 sweet potato combine harvester was described in detail based on the analysis of its overall structure, the conveyer mechanism of arc grid handover scraper chain was designed, and the working parameters were determined. Relying on the machine and sweet potato planting mode, the arc grid handover scraper chain conveying test bench was built. With potato tuber of loss rate and damage rate in the process of transferring of potato tubers as the main evaluation index, the single factor bench test was carried out with the angle of excavating and conveying mechanism, the angle of scraper chain conveying, the speed of excavation and conveying mechanism, the speed of scraper chain conveying, scraper angle and arc grid installation distance as test factors. The significance of the influence of each factor on each performance index, the influence rule, and the cause were analyzed. The test results showed that the angle of excavating and conveying mechanism, the conveying angle of scraper chain, the speed of excavating and conveying mechanism, and the conveying speed of scraper chain had significant impacts on the performance indexes, while the angle of the scraper and the installation distance of the arc grid had no significant impact on the performance indexes. When the angle of excavating and conveying mechanism was 24°, the conveying angle of the scraper chain was 60°, the speed of excavating and conveying mechanism was 1.15 m/s, and the conveying speed of the scraper chain was 0.69 m/s.The arc grid transfer scraper chain conveyor mechanism was more effective. The loss rate and the damage rate were 075% and 013%, respectively. The research results can provide a reference for the structural improvement and parameter optimization of the sweet potato combine harvester.

In view of the lack of research on the by-product management specifications of agricultural machinery research institutes in China, in order to formulate the by-product management specifications in line with its characteristics and reduce the loss of state-owned assets, the characteristics of the by-product production of agricultural machinery research were analyzed and put forward based on the description of the by-product management of planting agricultural research. The first characteristic was that the production of scientific by-products of agricultural machinery was not targeted at agricultural breeding. The second characteristic was the small amount of research by-products produced. The third characteristic was that agricultural machinery scientific research by-products damage was difficult to reach the requirements of marketing. The fourth characteristic was that there were fewer scientific research by-products such as scientific research machines or spare parts that can be marketed. The fifth characteristic was that agricultural machinery products on the market sales need qualification appraisal or certification of the subject was not scientific research units. And the management measures of scientific by-products in representative agricultural machinery research institutes were analyzed. New measures were put forward, such as the need to clarify the subject of responsibility for the management of scientific research by-products, ledger registration, disposal principles, methods and procedures, requirements for revenue and expenditure management, supervision and “red line”. It can be used as a reference for other domestic agricultural machinery research institutes to improve the management of scientific by-products.