Core-blowing machine for preparing moulds and foundry cores

In a core-blowing machine for making moulds, foundry cores and the like, said machine comprising a forming mass container, a sandslinger head arranged below said container, a ramming frame slidably arranged externally to a lower end of said sandslinger head so as to be vertically displaceable from a lowered position in which said ramming frame projects downwardly from said sandslinger head to a raised position in which said ramming frame is retracted around said sandslinger head, and a flask supporting table arranged below said sandslinger head and provided with means for vertically displacing said flask supporting table towards said head, the improvement comprising said ramming frame having an inner wall formed by an inwardly projecting upper portion in slidable contact with the outer surface of the lower end of said sandslinger head and a recessed lower portion having air venting holes and spaced from said outer surface so that at least one air venting passage communicating with said holes is defined between said outer surfaces of said sandslinger head and said inner wall of said ramming frame when said ramming frame is in its raised position.