Damage mechanism study of chain-lever elevator sweet potato harvester

4GS-1 500sweet potato harvester is a typical chain-lever elevator sweet potato harvester.In order to improve the chain-lever elevator and mitigate the damages on sweet potato in the course of transport-separating and throwing sweet potato,the experiments on Shangshu No.19,Fushu No.24,Zhengshu No.20were carried out with 4GS-1 500sweet potato harvester.The damage occurrence and the injured ratio were studied by mechanics,kinematic principle and test analysis.The results showed that the main damage was galled spots,internal tissue extrusion and break.The damage was mainly caused by shear,impact and friction among clod,sweet potato and the chain-lever.The ratio of the injured sweet potato was reduced to 1.5% by optimizing the rod structure and operational parameter of the chain-lever.