Mechanical height adjusting device for gantry crane

The utility model relates to the technical field of gantry cranes, and discloses a gantry crane mechanical height adjusting device which comprises a moving box, a supporting cylinder, lifting rods, a sliding rail, a lifting box, a lifting rope and a lifting hook, the supporting cylinder is fixedly arranged at the top of the moving box, the lifting rods are inserted into the supporting cylinder, the sliding rail is transversely and fixedly arranged between the two lifting rods, and the lifting rope is arranged in the lifting box. The lifting box is slidably arranged on the sliding rail, the lifting rope is fixedly arranged at the bottom of the lifting box, the lifting hook is fixedly arranged at the lower end of the lifting rope, a double-shaft motor is fixedly arranged at the top of the sliding rail, rotating shafts are fixedly arranged at the two output ends of the double-shaft motor, first bevel gears are fixedly arranged at the tail ends of the two rotating shafts, and an inner threaded cylinder is fixedly