Method for producing glass bottles by automatic forming and apparatus to carry out the method

A process for producing glass bottles with shoulders, in accordance with a cavity forming method comprising a preform preparation step and a finishing step, with blowing by compressed air or other gas, and 180° rotation of a preform between a preform mold and a finishing mold,

• wherein the preform preparation step is achieved by:
• a) introducing a glass gob into the preform mold through an upper aperture;
• b) from a base of the preform mold, inserting a blowing sleeve into the glass gob deposited on a base of a preform mold cavity, an end of said blowing sleeve extending beyond shoulders of an outline of the preform of a bottle produced in the finishing mold, said blowing sleeve being closed by a plunger slidable within an interior of said blowing sleeve;
• c) opening a cavity of the blowing sleeve to disengage the plunger;
• and
• d) blowing air through said blowing sleeve,
• wherein a final finishing step is achieved in an open preform mold operating as the finishing mold with a blowing head provided with a blowing tube, a volume of a cavity of said finishing mold being greater than a volume of the preform mold cavity of the preform mold by 5-20%.