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 (2) and a finishing mold (24),

• wherein the preform preparation step is achieved by:
• a) introducing a glass gob (40) into the preform mold (2) through an upper aperture;
• b) from a base of the preform mold, inserting a blowing sleeve (13) into the glass gob (40) deposited on a base of a preform mold cavity (6), an end of said sleeve (13) extending beyond the shoulders of an outline of the preform of a bottle to be produced, said sleeve (13) being closed by a plunger element (12) slidable within an interior of said sleeve;
• c) opening a cavity of the sleeve (13) to disengage the plunger element (12);
• and
• d) blowing air through said sleeve (13),
• wherein a final finishing step is achieved in an open preform mold operating as the finishing mold (24) with a blowing head provided with a blowing tube, a volume of a cavity (28) of said finishing mold being greater than a volume of the cavity (6) of the preform mold by 5-20%.