The mechanism supports mould side portions (10;110) on an upper support (50;150) and a lower support (52;152) both mounted on an arm (14) for limited movement in a horizontal plane. A force apportioning member (62;162) is mounted on the arm and pivotally engages both supports. The force apportioning member (62;162) pivots on a horizontal axis between the supports to apportion mould closure force between the supports. The pivots may be provided by spherical bearings (64,70;164;170).

A method of cooling a mould in a glassware forming machine wherein an intermediate support (26) supports a mould portion (10) and defines a space (36) which serves to insulate a movable support (14) of mould opening and closing mechanism of the machine from the mould portion (10). The mould portion (10) is cooled by blowing air into the space (36). The air blown into the space (36) increases the insulating effect of the space (36) and also can be blown through an aperture (40) in the intermediate support (26) on to the mould portion (10) so as to cool that portion of the mould portion (10).

A mold locking system is provided for a glass molding machine. The machine has first and second mold hanger support arms for moving respectively first and second mold halves. The arms are pivotally cantilever-mounted at their ends for rotation about a vertical axis between a retracted station where the mold halves are separated and a forming station where the mold halves are brought into contact. The locking system includes a pressure system for exerting an upward force on the free ends of the support arms and includes surfaces configured to pressingly engage specially configured portions of the free arm ends so that operation of the pressure system forces the free ends towards each other to ensure closure of the mold, and to force the free ends up against a limit stop to terminate upward travel to compensate for sag and mounting system wear.