US 5,100,607 AGranted

Blow-molding methods to form containers having upper and lower sections of different thicknesses

OwnerEdward S. Robbins, IIIinventor

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Abstract

A plastic container having base and sidewall portions is provided with corrugations as a unitary part of the sidewall portion. The sidewall portion is of a thickness that would not be capable of supporting itself without the unitary corrugations. The corrugations serve to rigidify, and this impart self-supporting capabilities to, the sidewall portion. The upper edge of the sidewall preferably includes a unitarily formed rim which assists in maintaining the sidewall in its generally tubular condition (and thus more easily facilitates the placement of articles in the container). The container may be closed by a flexible and gatherable terminal portion which is an integral extension of the rim or the upper edge of the sidewall. The containers of the invention are formed by an extrusion blow-molding technique using an appropriately configured blow mold.

Claims2

Dependent claims

A method of making a plastic container comprising a base portion, and a sidewall portion formed as a unitary tubular extension of said base portion, said sidewall portion unitarily including a self-supporting region having a number of longitudinally extending corrugations whereby the container may stand upright, and a non-corrugated flexible region having an open upper end, said method comprising the steps of:

forming said base and sidewall portions by extruding a plastics material to form sequentially continuous first and second portions of a parison having first and second wall thicknesses, which thicknesses will ultimately form said base portion and said sidewall portion, and said thickness which will ultimately form said sidewall portion being substantially less than said thickness which will ultimately form said base portion such that said sidewall portion is normally non-self-supporting while said base portion is normally self-supporting;
disposing said parison portions in a blow mold having mold walls configured to form said base portion and said corrugations in said self-supporting region, and said non-corrugated flexible region of said side wall portion;
imparting self-supporting capabilities to said normally non-self-supporting sidewall region by urging the first and second parison portions into respective conformance with the mold walls to form said base portion, said non-corrugated flexible region, and said self-supporting region having said unitary longitudinally extending corrugations, wherein the parison portion of said substantially less thickness forms said sidewall region having said unitary longitudinally extending corrugations and thereby imparts self-supporting capabilities thereto;
removing said formed container from said blow mold;
and
removing a portion of said plastics material from the upper end of said container to form said open upper end thereof, whereby said container is formed.

3 more elements

A method of making a plastic container comprising the steps of:

substantially simultaneously forming integral first, second and third generally tubular container portions in a single continuous process, wherein said first container portion includes a base portion, said second container portion includes a sidewall portion, and said third container portion includes a flexible terminal portion;
wherein
the step of forming said first container portion including the step of forming said base portion of a plastic material of a predetermined thickness;
the step of forming said second container portion includes the step of forming said side wall portion from said plastic material of a predetermined thickness substantially less than said predetermined thickness of said first portion but as an integral extension thereof, and also includes forming integral longitudinally extending corrugations in said side wall portion which impart self-supporting capabilities to said sidewall portion, and the step of forming said third container portion includes the step of forming said flexible terminal portion from said plastic material of a thickness which is not greater than the thickness of said sidewall portion;
said steps of forming said first, second and third container portions in a single continuous process includes continuously extruding first, second and third parison portions, the thickness of said second and third parison portions being substantially less the thickness of said first parison portion, and the thickness of said third parison portion being no greater than the thickness of said second parison portion;
disposing said first, second and third parison portions in a blow mold having mold walls, and urging said first, second and third parison portions into conformance with the mold walls to form the container having said integral first, second, and third container portions, and allowing the molded container portions to cool in the mold sufficiently whereby the container may be removed, and then removing the container from the mold.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/400,140Filed 29 Apr 1989 · division
Priority: 30 Jan 1987
Granted: 31 Mar 1992
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B29C 49/54
Moulds: for undercut articles
B65D 1/26
Boxes or like containers with side walls of substantial depth for enclosing contents: thin-walled containers, e.g. formed by deep-drawing operations
B65D 1/44
Reinforcing or strengthening parts or members: corrugations
Y10S 264/33
Plastic and nonmetallic article shaping or treating: processes: blow-molding articles of nonuniform thickness

Family

Serial8,658Parent of this continuation-in-part · filed 30 Jan 1987
Serial13,627Parent of this continuation-in-part · filed 11 Feb 1987
Serial123,325Parent of this continuation-in-part · filed 20 Nov 1987
Serial332,994Parent of this division · filed 4 Apr 1989
US 5,048,977 AParent of this continuation-in-part
US 4,836,970 AParent of this continuation-in-part
US 5,100,607 AThis patent

From the US filing history. Foreign family members aren’t listed.