Container having expanding or contracting end closure

Abstract: A container (10) has a movable end closure (18) for accommodating expansion or contraction of the product (8) packaged therein. The container includes a hollow body portion (12) with opposed open ends and an inside surface and an end closure positioned at each of the open ends of the hollow body portion and secured thereto for closing the container with product contained therein. One of the end closures is of a generally cup-shaped configuration and has a radially-extending central portion (21) of generally the same configuration and dimensions as the inside surface of the body portion and an accordion-folded sidewalk (22) extending axially from the central portion toward the body portion open end to define a free end area secured to the inside surface of the body portion at the open end. This end closure is positioned so that the central portion may axially move along the body portion inside surface toward or away from the body portion open end by contraction or expansion of the end closure accordion-folded side wall to increase or decrease the effective volume of space within the container.

Description: This invention relates to a container for packaging various products, including food products, having an end closure on at least one end of the container which contracts or expands to accommodate expansion or contraction of the product packaged within the container according to the preamble of claim 1. Background And Of The Invention Containers utilized for packaging various products, including food products, are often subjected to increased or decreased pressure within the container which results from either the product being packaged under a vacuum or the product expanding after it is placed in the container. This is typical of food products in which as much air as possible is pulled out of the container so that the product is under a vacuum or the packaging of a food product, such as a dough or the like, wherein the product expands after packaging. Composite containers including at least a paper body layer and a barrier liner layer and closed by paper end members also having barrier liner layers or metal end members are becoming increasingly more popular for packaging various products, including food products. These container constructions include problems with the walls or the body portion buckling outwardly under increasing pressure within the container resulting from product expansion or contracting inwardly when a vacuum is pulled on a product being packaged within the container. Composite container body portions, while providing economic advantages, do not provide the strength of metal or plastic containers. Even the metal or plastic containers can have the problems of buckling or contracting side walls due to the above changing conditions within the container. US 4,560,063 (corresponding to the preamble of claim 1) describes a container with a base that is deformable in response to internal pressure. FR 1,389,226A describes a container that has a lid that has a deformable part that can respond to changes in internal pressure. NL 6, 810,059C describes yet another container that can adapt to changes in internal pressure. Whilst these address some of the problems highlighted above, there is nevertheless a need for an improved container, which can contract or expand to accommodate expansion or contraction of the product packaged within it. Object And Summary Of The Invention Accordingly, it is the object of this invention to provide a container construction which overcomes the above problems and accommodates expansion or contraction of product packaged within the container. A container in accordance with the invention is defined in claim 1. Some preferred features are defined in the dependant claims. It has been found by this invention that the above object may be accomplished by providing a container having a movable end closure for accommodating expansion or contraction of product contained within the container by increasing or decreasing the effective volume of space within the container and comprising the following. An elongate body portion has opposed open ends and an inside surface. An end closure is positioned at each of the open ends of the hollow body portion and is secured thereto for closing the container with the product contained therein. One of the end closures is of a generally cup-shaped configuration having a radially-extending central portion of generally the same configuration and dimensions as the open end of the body portion and an accordion-folded side wall extending axially from the central portion toward the body portion open end and defining a free end area secured to the body portion at the open end and positioned so that the end closure central portion may axially move toward or away from the body portion open end by contraction or expansion of the end closure accordion-folded side wall. Preferably, the body portion of the container and the contracting or expanding end closure are constructed of composite materials which preferably include a paper layer and a barrier liner layer. Brief Description Of The Drawings In the drawings which form part of the original disclosure of the invention: Fig. 1 is an elevational view, mostly in section, of a container constructed in accordance with this invention and having a movable end closure in a contracted position resulting from a vacuum being pulled on the product contained within the container; and Fig. 2 is a partial elevational view, in section, illustrating the container of Fig. 1 with the movable end closure in an expanded condition resulting from expansion of the product contained within the container. Detailed Description Of A Preferred Embodiment Of The Invention Figs. 1 and 2 illustrate a container, generally referred to at 10', constructed in accordance with the present invention. Generally, the container 10' includes an elongate hollow body portion 12', preferably tubular in configuration, having opposed open ends 13' and an inside surface 14'. The body portion 12' may be constructed of suitable materials. The container 10' further includes end closures 17', 18' positioned at each of the respective open ends 13' of the hollow body portion 12' and are secured thereto for closing of the container 10' with product P' contained therein. One of the end closures 18' is of a generally inwardly-facing cup-shaped configuration positioned for the most part outside the hollow body portion 12' and has a radially-extending central portion 21' of generally the same configuration and dimensions as the open end 13' of the body portion 12' . The end closure 18' further includes an accordion-folded sidewall 22' extending axially from the central portion 21' toward the body portion free end 13' and defines a free end area 23' which is secured to the inside surface 14' of the body portion 12' at the open end 13' and positioned so that the end closure central portion 21' may axially move away from and toward the body portion open end 13' by expansion or contraction of the end closure accordion-folded sidewall 22' to increase or decrease the effective volume of space within the container 10' , as shown clearly in Figs. 1 and 2. The one end closure 18' may be constructed of suitable materials and may include a disk-like member 24' secured to or incorporated within the radially extending central portion 21' . The cup-shaped end closure 18' is preferably secured to the open end 13' of the hollow body portion 12' by providing the open end 13' of the body portion 12' with a generally inwardly-turned L-shaped cross-sectional configuration (as illustrated in Fig.2) so that the free end area 23' of the cup-shaped end closure 18' may be positioned within the inwardly-turned L-shaped body portion end 13'. An adhesive, heat seal or other bond, generally indicated at 26' is positioned between the inwardly-turned portion of the L-shaped body portion end 13' and the free end area 23' of the end closure 18' to bond and secure these components together. The other end closure 17' may preferably be paper or metal, This invention has been described in considerable detail with reference to its preferred embodiment. However, variations and modifications may be made within the scope of this invention as defined in the following claims.

Claims: A container (10') having a moveable end closure (18') for accommodating expansion or contraction of product packaged therein and comprising: an elongate hollow body portion (12') having opposed open ends (13') and an inside surface (14'); an end closure (17', 18') positioned at each of said open ends of said hollow body portion (12') and secured thereto for closing said container (10') with product contained therein; and one of said end closures (18') being moveable and defining a flat central portion (21') of generally the same configuration and dimensions as said open end of said body portion (12') and extending radially of said body portion (12') characterised in that the moveable end closure (18') has a generally inwardly facing cup-shaped configuration positioned for the most part outside said hollow body and an accordion-folded side wall (22') which is integral with and extends perpendicularly from said central portion (21') and axially toward said body portion open end and defines a free end area (23') which is secured to said inside surface of said body portion (12') at said open end and is positioned so that said end closure central portion (21') may axially move away from and toward said body portion open end by axial expansion or contraction of said end closure accordion-folded side wall (22') to increase or decrease the effective volume of space within said container (10') and respectively increase or decrease the effective volume of space within said cup-shaped moveable end closure. A container (10'), as set forth in claim 1 in which said body portion (12') of said container is constructed of composite materials and said contracting or expanding end closure (21') is constructed of composite materials. A container (10') as set forth in claim 2, in which said composite materials of said body portion (12') and said end closure (21') include a paper layer and a barrier liner layer. A container (10'), as set forth in claim 1 in which said opposed end (13') of said body portion (12') having said contracting or expanding end closures (21') defines a generally inwardly-turned L-shaped cross-sectional configuration, said free end of said cup-shaped end closure is positioned within said inwardly-turned L-shaped body portion end, and a bond (26') secures said free end of said end closure to said opposed end.

Inventors: REA KEITH, REA, KEITH
Applicants: SONOCO DEV INC, SONOCO DEVELOPMENT, INC.
Application year: 2000
Main classification: B65D3
IPC codes: B65D79