Large conical sand making machine with automatic protection function

The utility model relates to a large conical sand making machine with an automatic protection function. The large conical sand making machine can radically avoid damaging upper and lower racks of the conical sand making machine when the thickness of iron passing through a large conical sand making machine made sand discharge hole exceeds the maximum opening measurement of the discharge hole. The large conical sand making machine comprises a large conical sand making machine body, wherein a plurality of pressure maintaining cylinders are arranged around an upper rack of the large conical sand making machine body; upper lifting lugs are respectively arranged at the lower ends of the plurality of pressure maintaining cylinders; the upper lifting lugs and lower lifting lugs are respectively arranged on a lower rack; the upper lifting lugs are inserted in the space between the lower lifting lugs and are connected with the lower lifting lugs by gray iron axle pins. The large conical sand making machine has the advantages that the damages caused to the pressure maintaining cylinders in the upper and lower racks of the conical sand making machine, the lifting lugs and the racks when the thickness of iron passing through the discharge hole of the conical sand making machine exceeds the maximum opening stroke of the discharge hole are radically overcome; change of the gray iron axle pins becomes normal simple change.