Moulding unit for a plant for blow-moulding plastic containers, particularly bottles

aba, bA moulding unit for a plant for blow-moulding plastic containers from respective parisons comprises: two half-moulds, movable relative to each other between a position of opening and a position of closing at least one cavity for blow-moulding a respective container; and a locking device for locking the two half-moulds in the closed position, the locking device comprising two first fastening elements which are moved to, and normally held in, a locked position by at least one elastic actuating element.