초록 ▼

This specification discloses an improved apparatus and method for making bi-axially oriented containers in an injection blow molding machine. The parison is brought to the blow mold at orientation temperature, and the end of a reciprocating element is brought into contact with the end of the parison

This specification discloses an improved apparatus and method for making bi-axially oriented containers in an injection blow molding machine. The parison is brought to the blow mold at orientation temperature, and the end of a reciprocating element is brought into contact with the end of the parison and is shaped to prevent the end of the parison from shifting off center as the parison is blown and stretched axially while it expands circumferentially to obtain bi-axial orientation. The reciprocating element prevents the parison from shifting laterally in the blowing mold so that the stretching and the wall thickness of the blown article is uniform.

대표청구항 ▼

Apparatus for blowing plastic containers and bottles or the like including a parison-forming injection mold including a core rod around one end length of which a parison is molded, a blow mold to which the core rod and its parison are shifted from the injection mold, said blow mold including means f

Apparatus for blowing plastic containers and bottles or the like including a parison-forming injection mold including a core rod around one end length of which a parison is molded, a blow mold to which the core rod and its parison are shifted from the injection mold, said blow mold including means forming a blow-mold cavity in substantial alignment with the core rod, a substantially solid piston rod that slides longitudinally in a guide at the end of the cavity opposite the core rod and in alignment with the core rod, an end portion of the piston rod that confronts and contacts with the end of the parison when the piston rod is advanced to its limit of movement toward the end of the parison and core rod, means for retracting the piston rod away from the core rod as the parison moves away from the end of the core rod at the start of a blowing operation in the blow mold, the end portion of the piston rod having a substantially continuous concave surface into which the confronting end of the parison extends to hold the confronting end portion of the parison against lateral movement with respect to the longitudinal axis of the core rod and the piston rod during the blowing of the parison to the shape of the cavity of the blow mold, means for stopping the travel of the piston rod when the end portion of the piston rod reaches a position where it cooperates with an annular bottom of the blow mold that surrounds said piston rod in the end of the cavity remote from the core rod so that the bottom of the blow mold and the concave end surface of the piston rod provide a support for the entire area of the bottom of a fully blown container in the mold, said concave end surface of the piston rod having projections that extend into the bottom surface of the parison to prevent lateral movement of the parison with respect to the concave end surface of the piston rod, said projections extending beyond the concave end surface of the piston rod for a distance less than the thickness of the blown parison.