Method and apparatus for forming glass containers

The method of forming lightweight glass containers comprising the steps of:

• positioning a one-piece plunger or neck pin having a generally horizontal, grooved surface coaxially within the neck mold of an inverted parison mold, neck mold combination;
• forming a charge of molten glass;
• loading the charge into the closed, inverted parison mold, neck mold and central plunger combination;
• applying a vacuum to the neck mold after sealing of the mold cavity by the charge of glass to thereby settle the charge into close contact with the plunger and neck mold;
• withdrawing the plunger from the neck mold without removing substantial heat from the glass charge while closing the upper end of the parison mold with a baffle;
• applying a counterblow air to the interior of the charge past the withdrawn plunger;
• continuing counterblow application for a time sufficient to complete counterblow of the charge into a parison defined by the interior of the parison mold and the baffle;
• opening the parison mold and removing the baffle therefrom;
• transferring the parison by inverting the neck mold from the parison mold position to a blow mold;
• injecting counterblow air through the vacuum passages to the plunger to purge them;
• reverting the neck mold after release of the parison at the blow mold;
• and
• repositioning the plunger, neck mold and parison mold into charge-receiving position.