Mechanical expander

The utility model discloses a mechanical expander, and relates to the technical field of fire rescue devices. The whole sleeve is arranged on the reference rod in a sliding and sleeving manner; the hydraulic assembly is integrally arranged on the reference rod, the sleeve is connected with the hydraulic assembly, and the hydraulic assembly enables the sleeve to linearly move along the reference rod; the first fixing ring is coaxially fixed with one end of the reference rod, and two second fixing plates which are centrosymmetric are fixed on the outer side wall of the first fixing ring; one ends of the two first opening plates are rotationally mounted on the two second fixing plates respectively; and the second fixing ring is coaxially fixed to the outer side of the sleeve, and two fourth fixing plates which are in central symmetry are fixed to the outer side of the second fixing ring. The utility model has two modes, namely a seam expanding mode and a hole expanding mode, so that the functions are diversified