Method for forming hollow glass articles

Claim 1

IN A METHOD OF CENTRIFUGALLY CASTING A HOLLOW GLASS ARTICLE HAVING A GENERALLY FRUSTO-PYRAMIDAL SHAPE IN A ROTATABLE OPEN-TOPPED MOLD HAVING DISTINCT SOMEWHAT ARCULATE SIDEWALLS JOINED AT RADIUSED CORNERS, SAID SIDE WALLS FLARING UPWARDLY AND OUTWARDLY FROM A LOWER APEX PORTION, BY THE STEPS OF INTRODUCING A CHARGE OF MOLTEN GLASS INTO THE APEX PORTION OF THE MOLD, INSERTING A PRESSING PLUNGER INTO THE MOLD, AND INTO CONTACT WITH THE GLASS CHARGE THEREIN, AND FINALLY RAPIDLY ROTATING THE MOLD TO CENTRIFUGICALLY MOVE THE MAJOR PORTION OF THE CHARGE TO AND ALONG THE FLARING SIDE WALLS OF THE MOLD, THE IMPROVEMENTS, PERFORMED PRIOR TO RAPID ROTATION OF THE MOLD, OF UTILIZING SAID PRESSING PLUNGER TO CARRY OUT THE STEPS OF (1) PRESS-FORMING A LOWER PORTION OF THE CHARGE TO A FINAL, ESSENTIALLY RIGID SHAPE CONFORMING TO A FINISHED PORTION OF SAID ARTICLE AND (2) DISTRIBUTING AN UPPER PORTION OF SAID ARTICLE AND (2) DISTRIBUTING AN UPPER PORTION OF THE CHARGE SO THAT THOSE PORTIONS OF THE CHARGE SUBSEQUENTLY MOVED TO AND ALONG THE CORNERS OF THE MOLD ARE OF REDUCED MASS AND THOSE PORTIONS OF THE CHARGE SUBSEQUENTLY MOVED TO AND ALONG THE SIDE WALLS OF THE MOLD ARE OF INCREASED MASS, SAID STEP (2) BEING CARRIED OUT WITHOUT COOLING THE UPPER PORTION OF THE CHARGE TO AN EXTENT SUCH THAT THE MOBILITY THEREOF IS SUBSTANTIALLY HAMPERED.