Mould arrangement for a cyclicly operating glassware forming machine

A mould arrangement for use in a cyclicly operating glassware forming machine, the arrangement comprising two supports on each of which one of two opposed side portions of a mould is mounted, each side portion defining side portions of a cavity of the mould which has an upwardly-facing opening through which molten glass can be introduced into the cavity to be moulded to the shape of the cavity, the supports being movable in a cycle of operation of the machine to a first position thereof, in which the side portions engage one another to co-operate in defining the mould cavity so that moulding can take place, and to a second position thereof, in which the side portions are separated from one another so that the moulded glass can be removed from the mould, the side portions also defining cooling passages each extending downwardly from an entrance in an upper surface of the side portion so that air can pass through the passages to cool the side portion, wherein the mould arrangement also comprises two plenum chambers each of which is associated with a separate one of the supports and is mounted for movement therewith, each plenum chamber extending above the upper surface of the side portion mounted on its associated support without obstructing the opening of the cavity, each plenum chamber having one or more exits which open downwardly and communicate with the entrances of the cooling passages in said side portion so that air supplied to the plenum chamber is supplied to each cooling passage at substantially the same pressure, each plenum chamber also having an entrance connected to air supply means operable to blow air into the plenum chamber.