Method of making a ribbon blown glass article

A method of continuously forming a blown glass envelope terminating in a self-supporting base end from a molten ribbon of glass supported on a moving conveyor which comprises:

• (a) blowing a portion of the glass from said molten ribbon into the central cavity of a single multi-part mold, said mold including a pair of cooperative halves forming the sides of said blown glass while being blown and which mold further includes a separate base part located at the lower end of said cavity to form the self-supporting base portion of said blown glass envelope, said base part of the mold being provided with reciprocal motion in a vertical direction,
• (b) having the base part of said mold move upwardly and remain in an upward position while the glass envelope is being blown to form all structural features in said blown glass envelope but then move downwardly and release the lamp glass envelope before the mold halves are opened,
• (c) opening the mold halves to release the sides of the solidified blown glass envelope, and
• (d) severing the blown glass envelope from the moving glass ribbon.