Envelopes – wrappers – and paperboard boxes – Paperboard box – With closure for an access opening
Reexamination Certificate
2002-01-22
2004-03-02
Mai, Tri M. (Department: 3727)
Envelopes, wrappers, and paperboard boxes
Paperboard box
With closure for an access opening
C229S125420
Reexamination Certificate
active
06698650
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relate to a pull tab for assisting opening of a sealed boxed end openable container.
2. Description of the Prior Art
Many materials, notably fluids such as milk or fruit juices, are put up in sealed containers for transport and storage prior to use when the container is opened and the contents discharged. Many forms of containers are used for this purpose, but one form is a thin walled carton made from a thin card or plastic sheet material and having a generally squared or rectangular cross-section and a cuboid or brick-like overall shape. The contents of such a container are typically fed to the container through an open top end of the container, the other end being having been closed by folding over the basal portion of the side walls to form a boxed end to the container. When the desired amount of material has been fed to the container, the open top of the container is closed by forming transversely directed V folds in the upper portions of two opposed side walls, with the apexes of the Vs directed inwardly towards one another. This has the effect of bringing the top portions of the other two side walls of the container together to form a tented top to the container having a ridge lying along the line of indentation of the V folds. The ridge is then heat sealed or otherwise processed so as to secure together the opposed faces of the upper portions of the V folded and other side walls in a single linear transverse strip seal closure to the container, at least the major portion of the closure being located within the overall cross-sectional plan area of the container.
The sealed ridge is often then folded down about a transverse fold line located extending across approximately the midpoint of one of the side walls of the tented top, so as to form a flat boxed end to the container. In some forms of such a closure, a tape, which can be wire-reinforced, is included in the line of the ridge, for example during folding over of the ridge material. This tape extends beyond the ends of the ridge to provide extensions which can be bent over to secure the folded down ridge in position by engaging the free ends of the tape under the lip formed along the edge of the boxed end where the V folded portion of the container wall is indented. Alternatively, the free ends of the extensions can be adhered or otherwise secured to the side walls of the container once the ridge has been folded down to form a boxed end to the container.
For convenience, the following terms will have the following means herein:
boxed end openable containers are containers of the above described general type and will be referred to herein as such containers;
ridge seal will be used to denote the transverse linear seal between the opposed faces of the top end portions of the side walls of the container;
ridge will be used to denote the exposed top edge of the ridge seal or the edges of the wall material which has been brought together prior to forming the ridge seal;
ridge structure will be used to denote the structure formed by bringing together the top end portions of the gabled and tent side walls of the container and which are secured together by adhesion between opposing faces at the interface between those opposing faces to form the ridge;
gabled end will be used to denote the structure formed at the top end of the container by indenting the upper portions of two opposed side walls of the container to form the ridge to that end of the container;
tented end will be used to denote the end of the container with the ridge in the raised position either before or after forming the ridge seal;
gabled side walls will be used to denote the upper portions of the two opposed side walls of the end of the container which have been indented by forming a V or other axial fold in the upper portion of the side wall so that the wall is collapsed laterally inwardly to form the gabled end to the container;
tent side walls will be used to denote the two opposed side walls of the sealed top which extend between the gabled side walls of the gabled end of the container;
wet wall surface will be used to denote an internal surface of the container which is to be in contact with the contents of the container, including the upper portions of walls which are to be incorporated into the ridge seal;
dry wall surface will be used herein to denote an external surface of the container which is not in contact with the contents of the container, including the upper portions of walls which are to be incorporated into the ridge seal.
To open such a boxed end openable container, the seal at the interface between the opposing dry wall surfaces of the V fold at one end of the linear ridge seal is separated. This forms a pair of wings in the gabled end so that the plan view configuration from above of the ridge seal to the container adopts a Y shaped configuration in place of a single line seal. The top edges of the wings forming the head of the Y remain sealed together. The wings are then bent backward to lie in line with each other, ie. so that the plan view configuration from above of the ridge seal adopts a T shaped configuration with the wings forming the head of the T. The free ends of the wings are then pressed inwardly towards the centre line of the upright of the T to apply a separating force transverse to the line of the seal at the intersection of the head and the upright of the T. This causes the seal between the opposed faces of the wet walls at the top edges of the container to separate at this intersection and to form an opening through which the contents of the container can be discharged. In some cases it may be desired to bend the wings beyond the in-line configuration so as to enhance the separating force applied to the seal at the intersection upon the application of pressure to the free ends of the wings.
However, separation of the seal is often incomplete and/or the wings collapse so that the user cannot continue to apply the separating force to the seal. It is therefore usually necessary for the user to insert a fingertip into the initial opening formed at the intersection to assist full separation of the seal between the faces of the wet walls to allow the V fold in the wall of the container to be unformed and then inverted to form a spout outlet to the container.
In many cases the initial separation of the seal between the wet walls at the intersection is insufficient to form an aperture into which the user can insert a finger tip. It is then necessary for the user to pinch the dry wall material in the unfolded gabled end wall of the container in the region of the V fold and try to pull the wall outwardly to assist separation of the seal. Such separation of the seal may occur abruptly, causing spillage of the contents of the container, and the need for such additional operations to separate the ridge seal is inconvenient.
Notwithstanding these problems in forming the opening to the container, the boxed end openable container provides a simple and effective container for the storage and transport of a wide range of fluids and remains widely used.
We have now devised a form of pull tab which can be secured to the exterior of the container wall and pulled by a user to apply a transverse separation force to the ridge seal whilst still in its linear or T or Y configuration. This separates the opposed faces of the wet walls of the ridge seal from one another to open the container. The form of the pull tab of the invention can be surprisingly firmly secured to the wall and resists removal from the wall of the container when the pull tab is pulled by a user to provide a container which is remarkably easy to open and is less prone to partial separation of the ridge seal than previous designs of pull tab or container.
The pull tab of the invention can readily be incorporated into the structure of the container with little or no modification to the container manufacturing and filling processes, notably where the pull tab is applied to the flat blank of ca
Laker Jonathan Paul
Laker Kirk Anthony
Easycarton Limited
Gunter, Jr. Charles D.
Mai Tri M.
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