Automatic yarn twisting instrument with positioning mechanism

The invention belongs to the technical field of yarn twist testing, and particularly relates to an automatic yarn twist instrument with a positioning mechanism, which comprises a base, a twist testing mechanism arranged at the right end of the base, and the positioning mechanism used for mounting a yarn roller; the positioning mechanism comprises a rotating disc rotationally connected to the base, a fixing disc is fixedly connected to the upper end of the L-shaped column, the fixing disc is distributed in the radial direction and is in sliding connection with a plurality of adjusting blocks through sliding grooves, placing blocks are rotationally arranged at the upper ends of the adjusting blocks, and a groove disc is rotationally arranged at the lower end of the fixing disc; a first guide column is embedded in the groove disc through a groove and is in sliding connection with the groove disc, the upper end of the first guide column is fixedly connected with an adjusting block, and cylindrical and conical yar