Apparatus for blow molding plastic articles

Claim 1

Apparatus for forming hollow plastic articles having neck and body portions comprising: a. means for extruding moldable plastic material downwardly through an outlet orifice to form a generally tubular length of the material, said extruding means including an extrusion head having a vertically extending cavity therein, said head having an inwardly directed shoulder at its lower end defining an outlet opening therein, an axially movable mandrel within said cavity having a passage therein for pressurized gas and an inwardly tapering lower end portion in axial alignment with said shoulder adapted to move axially, momentarily downwardly substantially against said shoulder to at least partially sever the tubular length from the remainder of the plastic in the extrusion head; b. a clamping assembly for clamping the tubular length below the outlet orifice to form a sealed portion of the length having a closed bottom end; c. first means for injecting gas into the sealed portion of the length through the passage in the head to expand said sealed portion; d. a partible mold adapted to close separately from the clamping assembly and having a cavity conforming to the shape of the article for enclosing the expanded sealed portion; and e. second means distinct from said extruding means for injecting gas to further expand the sealed portion against the walls of the mold cavity to form the article.