Positioning clamp for numerical control machine tool

A positioning clamp for a numerical control machine tool comprises a chuck shell, an installation hole is formed in the side portion of the chuck shell, an installation shaft seat is fixed in the chuck shell, a rotating rod is installed on the installation shaft seat, one end of the rotating rod is inserted into the installation hole, and a driving bevel gear is fixedly installed at the other endof the rotating rod and meshed with a bevel gear face on the lower portion of a butterfly bevel gear. An adjusting hole is formed in the end, inserted into the mounting hole, of the rotating rod and used for allowing a chuck adjusting wrench to be inserted therein, a sliding groove is formed in the chuck shell on the side of the mounting hole, a limiting block is fixed to the end, close to the mounting hole, of the sliding groove, a moving seat is mounted in the sliding groove, and an extrusion spring is mounted between the side, away from the mounting hole, of the moving seat. A top block isinstalled on the side, clo