Jig circulation assembly line and jig backflow device

The invention discloses a jig circulation assembly line and a jig backflow device. The jig backflow device comprises a feeding mechanical hand, a conveying structure and a vertical lifting structure,wherein the feeding mechanical hand is arranged at the input end of the conveying structure, and is used for putting jigs on the conveying structure; the conveying structure is sequentially divided into a rising section, a straight section and a slow descent section from the input end to the output end; the rising section, the straight section and the slow descent section are of belt transmissionstructures; the rising section of the conveying structure is upwards obliquely arranged; the straight section of the conveying structure is horizontally arranged; the input end of the straight sectioncorresponds to the rising section; the output end of the straight section corresponds to the slow descent section; the slow descent section is downwards obliquely arranged; and the vertical lifting structure is arranged at the