US 4,889,752 A · One piece self-standing blow molded plastic containers

Abstract

An improved one-piece plastic container of the champagne base variety having an annular peripheral chime surrounding an inward sloping base portion for containing carbonated beverages and associated methods for making same by blow molding. The preform defining interior and exterior walls which are ever decreasing in diameter from the neck to the base so that the preform may be easily removed from a mating core and injection mold cavity used therewith thereby avoiding the need for a split mold to form the preform. In a blow molding process for producing a one-piece plastic container by expanding an elongated preform containing plastic material for the neck, body and base of the container in a mold, the process for forming a container of the champagne base variety comprising the steps of forming the preform on a core rod with annular thickened portions of the preform positioned at points along the length thereof such that during blowing of the preform the material of the preform will be deposited where desired; positioning the preform within a blow molding cavity defining the finished container shape; extending a stretch rod within the preform towards the bottom of the blow molding cavity, prior to injection of pressurized gas, to longitudinally stretch a sidewall-forming portion of the preform while minimizing stretching of a base-forming portion thereby inducing the base-forming portion to lay down where desired when injected with pressurized gas; and injecting pressurized gas into the preform adjacent the neck whereby the preform is radially stretched outward to fill the cavity and form the container from the neck towards the base.

Claims47

Dependent claims

A one-piece plastic container of the champagne base variety having a neck, sidewall and base having an annular peripheral chime surrounding an inward sloping base portion for resisting inversion of the base due to internal pressure when containing carbonated beverage:

(a) the inward sloping base portion being of thickness sufficient to resist self-deformation and create a moment arm thereof around the chime tending to unroll and radially stretch the chime;
and
(b) the chime being of thickness sufficient to create an integrated reinforcing hoop to prevent unrolling and radial stretching of the chime which would allow inversion of the inward sloping base portion;
the container being made in a blow mold in a blow molding process using a stretch rod comprising
(c) producing a preform containing material for said neck, sidewall and base of the container;
wherein the preform has an open neck to form the neck, a sidewall-forming portion of uniform thickness and a base-forming portion, the base-forming portion including an annular thickened portion shaped and positioned for engagement by a stretch rod,
(d) extending a stretch rod within the preform for longitudinally stretching the sidewall forming portion while minimizing stretching of the base forming portion, and
(e) injecting pressurized gas to blow the preform to produce the container.

5 more elements

A preform for use in a blow molding process for producing a one-piece plastic container by expanding a hollow preform containing material for a neck, sidewall and base of the container in a mold;

wherein the preform has an open neck to form the neck, a sidewall-forming portion of constant thickness and a base-forming portion including an annular thickened portion positioned such that following blowing of the preform the material of the base-forming portion is deposited to form an inward sloping base portion which is of a thickness sufficient to resist self-deformation and to create a moment arm around a chime tending to unroll and radially stretch the chime, the chime having an integral reinforcing hoop formed therein to prevent unrolling and radial stretching of the chime which would allow inversion of the inward sloping base portion;
wherein at the point where said sidewall-forming portion and said base-forming portion meet, the preform has an annular axially directed nub, formed in the inner surface thereof, axially terminating the annular thickened portion and shaped to mate with a matching annular groove oppositely directed axially of a stretch rod when disposed within the preform.

A preform for use in a blow molding process for producing a disposable one-piece plastic container by expanding a hollow preform containing material for a neck, sidewall and base of the container in a mold;

wherein the preform has an open neck to form the neck, a sidewall-forming portion of uniform thickness and a base-forming portion having a closed end and including an annular thickened portion, the entire thickness of which is thicker than the sidewall-forming portion and the closed end of the base-forming portion, positioned such that following blowing of the preform the material of the base-forming portion is deposited to form an inward sloping base portion which is of a thickness sufficient to resist self-deformation and to create a moment arm around a chime tending to unroll and radially stretch the chime, the chime having an integral reinforcing hoop formed therein to prevent unrolling and radial stretching of the chime which would allow inversion of the inward sloping base portion;
wherein at the point where said sidewall-forming portion and said base-forming portion meet, the preform has an annular surface, formed in the inner surface thereof, axially terminating the annular portion of a stretch rod when disposed within the preform;
the annular surface is positioned adjacent a transition from the sidewall-forming portion to the base-forming portion whereby upon stretching of the preform, following desired temperature conditioning and preparatory to blowing to form the container, by a stretch rod engaging the annular surface, the sidewall-forming portion is stretched axially while the baseforming portion remains substantially undeformed.

A preform, for blow molding a one-piece self-standing plastic container having a neck, sidewall and base, comprising an open neck portion to form the neck, a sidewall portion to form the sidewall and a closed end base portion to form the base, the preform defining interior and exterior surfaces which are ever decreasing in diameter from the open neck to the closed base, wherein an annular thickened portion located in the base portion is provided to form a reinforced annular chime region in the container once formed, the entire thickness of the thickened portion being thicker than the sidewall portion and thicker than the preform between the thickened portion and the closed end of the base portion, wherein;

at the point where said sidewall portion and said base portion meet, the preform has an annular surface facing the open neck portion formed in the inner surface thereof and shaped to mate with a matching annular surface of a stretch rod when disposed within the preform to facilitate axial stretching of the sidewall portion while the base portion remains substantially undeformed;
the thickened portion is defined by the annular surface and the exterior shape of the base portion, said exterior shape being a conically tapered portion, commencing adjacent the annular surface and decreasing in diameter to merge with an external surface defining the exterior of the closed end;
and
the annular surface comprises a conically tapered surface, of less taper than the conically tapered portion, terminating in an internal surface defining the interior of the closed end.

1 more element

A preform for blow molding a one-piece self-standing plastic container having a neck, sidewall and base, comprising an open neck portion to form the neck, a sidewall portion to form the sidewall and a closed end base portion to form the base, the preform defining interior and exterior surfaces which are ever decreasing in diameter from the open neck to the closed base, wherein an annular thickened portion located in the base portion is provided to form a reinforced annular chime region in the container once formed, the entire thickness of the thickened portion being thicker than the sidewall portion and thicker than the preform between the thickened portion and the closed end of the base portion, wherein;

at the point where said sidewall portion and said base portion meet, the preform has an annular surface facing the open neck portion formed in the inner surface thereof and shaped to mate with a matching annular surface of a stretch rod when disposed within the preform to facilitate axial stretching of the sidewall portion while the base portion remains substantially undeformed;
the thickened portion is defined by the annular surface and the exterior shape of the base portion, said exterior shape being a conically tapered portion merging with an external surface forming the exterior of the closed end;
and
the annular surface joins the interior surface of the wall portion to a conically tapered interior surface of the base portion which terminates in the interior surface of the closed end, the tapered interior surface having less taper than the conically tapered portion.

1 more element

Dependencies are inferred from the claim text.

One piece self-standing blow molded plastic containers

Life of this patent

One piece self-standing blow molded plastic containers

Life of this patent

Abstract

Claims47