Variable cross-section engineering machinery tensioning spring

The utility model discloses a variable cross-section engineering machinery tension spring which comprises a small spring and a large spring which are different in inner diameter, one end of the large spring is connected with one end of the small spring, and the small spring and the large spring which are spliced together are used for adapting to the variable cross-section change condition in engineering machinery. The two fixing rings are connected to the ends, facing each other, of the large spring and the small spring, the diameters of the two fixing rings are matched with the inner diameters of the small spring and the large spring, a plurality of symmetrically-arranged annular grooves are formed in the two fixing rings, and the inner walls of the annular grooves are rough. According to the variable cross-section requirement in engineering machinery, the large spring and the small spring are spliced for manufacturing, according to the specific variable cross-section size requirement, the large spring corre