Side cutting head clasping device for three-knife trimmer

The utility model relates to the field of trimmer products, in particular to a side cutting head clasping device for a three-knife trimmer. The side cutting head clasping device for the three-knife trimmer comprises a side cutting head, a locking screw which is inserted into an opening of the side cutting head, a base, a tensioning block, an air cylinder with a piston rod, a transmission shaft and transmission blocks, wherein the base is fixed on the side cutting head; the top of the tensioning block is connected with the piston rod in the air cylinder; installing holes are formed in the side walls of the base; a control hole which corresponds to the installing holes is formed in the tensioning block; the transmission shaft is inserted into the installing holes and the control hole; a part of the transmission shaft, which is connected with the control hole, has an eccentric shaft structure; the tail end of the transmission shaft is fixedly connected with one end of a corresponding transmission block, and the