Patent Description:
Tube style containers for containing foodstuffs such as crisps (or "chips") are well known and generally comprise a cylindrical composited tube (e.g. layers of paper, cardboard, polymer, aluminium foil, cardboard) formed by spiral winding and bonding. The bottom of the tube is closed with a circular metal end using an end seaming process. The top of the tube may be folded over so as to provide an upper rim that surrounds the opening. In order to close the top opening of the tube, a composite peelable lid is secured to the upper rim surrounding the opening, e.g. using a heat sealing process. The lid may be formed of a thin layer of metalized plastic.

In order to protect the peelable lid during filling, transit and storage, a plastic overcap is usually provided, the overcap snap-fitting over the end above the peelable lid. As well as providing this protection, the plastic overcap allows reclosure of the container after a consumer has opened the container by either fully or partially removing the peelable lid.

It is extremely desirable to reduce the use of plastics in disposable products and to replace these with more fully recycle-able materials such as metals.

<CIT> describes a container according to the preamble of claim <NUM>, comprising a metal container body having an access aperture with a curled rim, and a cap for closing the access aperture, characterised in that said rim and said cap are provided with formations which are inter-engageable by a turning movement of the cap, to secure the cap on the container body.

<CIT> describes a membrane lid having a recessed ring pull tab. The membrane lid comprises a permanently deformable layer (e.g., metal foil or thin sheet metal) having a disk portion and a tab projecting from the outer periphery of the disk portion. The tab is folded back onto the upper surface of the disk portion. A region of the disk portion underlying the folded-back tab defines a depression and the tab is folded back such that it is recessed within the depression. A sealing material is provided on the lower surface of the membrane lid for sealing the lid to a metal ring of a container.

<CIT> describes a metal package with an annular rim folded down towards the outside. The metal package comprises an annular rim defining an external roll with an approximately triangular cross-section and having a peripheral necking inclining towards the inside of the internal surface of the said annular rim, which extends in the prolongation of the internal wall of the package. The structure of this annular rim facilitates the flow of the product contained in the can and simplifies the fixing of a sealing lid.

<CIT> describes a frangible membrane employed to protect the contents of a tin. It consists of one or more layers of soft metal (lead or tin) foil or waterproof transparent cellulose foil, these materials being used singly or in combination. The material is sealed into the seamed joint between the end frame, or annulus, and the body flange of the container, by the aid of a coating of rubber latex cement or other rubber-based adhesive applied to some or all of the surfaces forming the joint.

According to the present invention there is provided a container comprising a substantially tubular metal container body having a top opening defined by an outwardly curled edge, and a bottom opening. The container further comprises a peelable lid bonded to an upper surface of said curled edge to close said top opening in an airtight manner, the outermost edge of the peelable lid not extending beyond an outermost extent of said curled edge, and a metal closure comprising a generally planar centre panel and a downwardly extending sidewall depending from a peripheral region of the centre panel and terminating with an inwardly directed fold, and a plurality of features pressed into the sidewall at respective circumferentially spaced locations between said peripheral region and the fold, wherein an innermost radius of the fold is less than an outermost radius of the outwardly curled edge of the container body, but said innermost radius lying outside of the innermost extent of the features, and wherein the radial inward extent of the features is greater than that of the fold. The closure and the container body have relative dimensions to allow the features to pass over said curled edge during closure and to be retained beneath the curled edge to resist removal of the closure.

The innermost radius of said inwardly directed fold of the closure being less than an outermost radius of the outwardly curled edge of the container body, but said innermost radius lying outside of the innermost extent of said features, allows for the inwardly directed fold to very easily snap over and under the outwardly directed fold of the top opening of the container body.

The metal closure may comprise three features substantially equi-angularly spaced around the circumference of said sidewall.

The peelable lid may comprise a layer of aluminium foil bonded to a layer of polypropylene, the bond between the peelable lid and said upper surface of said curled edge being formed between the polypropylene and the metal of the curled edge.

The tubular metal container may be a circular cylinder and said metal closure may be substantially circular.

The container may comprise a metal end, seamed to said bottom opening to close the bottom opening in a substantially airtight manner.

A gap between said outermost edge of the peelable lid and an outermost extent of said curled edge may be in the region of <NUM> to <NUM>, for example <NUM>. Each said feature may have an innermost surface with an axial extent of between <NUM> and <NUM>.

The peelable lid and said features may either not overlap to a radial extent or may overlap by <NUM> or less.

The downwardly extending sidewall of the metal closure may have a length in the range <NUM> to <NUM>, preferably <NUM>.

The curled edge of the container body may be open.

The inwardly directed fold may have a radial extent of between <NUM> and <NUM>, for example <NUM>, and/or said fold may be formed as a curl or hem.

Each of said features have inclined upper and lower surface regions. This facilitates pressing of the closure over the outwardly curled edge of the top opening of the container body.

A tubular container will now be described that is substantially made of metal to allow for recycling. The container is suitable for containing a foodstuff such as crisps, providing a substantially air and water-tight seal prior to first opening. The closure is also designed to be re-closable such that when reclosed the interior of the container is protected from dust and other contaminants.

<FIG> is an isometric view of the container <NUM> prior to first opening. The container comprises a tubular metal body <NUM> formed by rolling a rectangular flat sheet into a cylinder and joining the abutting ends by welding, such that a seam (not shown in the drawing) is formed along the length of the container body. A generally circular end <NUM> is secured to the base of the container body using a conventional seaming process, e.g. involving curling an upstanding wall of the end together with the bottom rim of the container body to form a curl within a curl. A metal overcap or closure <NUM> is fixed to the top of the tubular body using a snap-fit mechanism involving a number or inwardly projecting and circumferentially spaced features <NUM> which, in this case, are formed as "pips" (only one of the pips is visible in the drawing). The closure diameter is <NUM>. In this example the closure comprises three pips <NUM>, spaced at <NUM> degree intervals around wall <NUM> of the closure, surrounding a closure centre panel <NUM>. As described below, a peelable foil lid (not visible in <FIG>) is sealed to the end of the tubular body and sits beneath the closure <NUM>. The tubular metal body may be "necked" at one or both of the top and the bottom, such that the body tapers inwardly towards the end(s). This may be desirable for performance and/or cost reasons.

The tubular body <NUM>, end <NUM> and closure <NUM> may be made of any suitable and recycle-able metal, such as tin-plated steel.

Although not described here in detail, a container manufacturer might provide the container body to a product filler with the peelable foil lid and closure in place, but with the bottom end open. The filler fills the container with product through the open bottom end before closing the container by seaming on the end <NUM>.

<FIG> is a top plan view of the container <NUM> of <FIG> and in which only the metal closure <NUM> is visible, whilst <FIG> shows a vertical cross-section taken along the line A-A of <FIG>. Visible in this drawing are the tubular metal body <NUM> and the metal closure <NUM>, as well as a peelable foil lid <NUM> which sits beneath the closure. The foil lid <NUM> may be formed of a multi-layer material, for example a top layer of aluminium foil (e.g. <NUM> microns or less in thickness) and a lower layer of polypropylene, PPE (e.g. <NUM> microns in thickness or less). The foil lid may be formed with corrugations, ridges, or other regular or non-regular deformations for the purpose of taking up slack in the material and/or providing improved pressure performance of the closed container. It is noted that the peelable lid may be made of other suitable materials including paper, cardboard and plastics, or any combination of these.

<FIG> shows a detail B of the vertical cross-section of <FIG>, illustrating certain dimensions of the container and further illustrating the position of the peelable foil lid <NUM>.

It will be appreciated that the upper end of the tubular boy is provided with an outwardly directed curl <NUM> such that the outer diameter of the curl is <NUM> (the outwardly directed curl lies radially outside of the tubular body). Further dimensional details of the curl are shown in <FIG>. A peripheral and circumferential region (outer edge) of the foil lid <NUM> is bonded to an upper surface of the curl <NUM>. This may be achieved using a heat seal process, which uses induction heating to heat the tubular body <NUM> in the region of the curl <NUM>. The foil lid <NUM> is then applied over the opening with a pressure applied to press the peripheral region onto the curl <NUM>. The residual heat softens the PP layer without causing any significant flow of material. As the PP cools, a bond is formed between it and the surface of the curl <NUM>. The outermost edge of the foil lid <NUM> stops short of the outermost surface of the curl <NUM>. The gap between these two regions is <NUM>.

<FIG> shows a plan view of the foil lid <NUM>, which includes a (pull) tab <NUM> to aid removal of the foil lid flowing removal of the closure <NUM> by a consumer. The tab may fully extend over the curl <NUM>, being pressed over the outside of the tubular body by the closure <NUM>, or may be folded back over the main body of the lid so that it is hidden by the closure (prior to first opening).

<FIG> shows an isometric view of the closure <NUM> removed from the container body <NUM> and upturned. In this view, the three circumferentially spaced pips <NUM> are clearly visible. Each pip may have an angular extent of less than <NUM> degrees, optionally less than <NUM> degrees, with sloping sidewalls extending from the outermost edge of the pip to an innermost rectangular region. As is apparent from <FIG>, the lowermost edge of the closure wall <NUM> is provided with a narrow inwardly directed fold such as a hem or curl <NUM> having a radial extent of <NUM>. [As will be apparent from the drawings, the fold <NUM> of this embodiment does not extend radially beyond the closure wall <NUM> so that the circumference of the closure presents an essentially flush surface. ] The fold <NUM> may be flattened to some extent or otherwise formed flat, to provide a "hem". The pips on the other hand have a greater radial extent of <NUM> (<NUM>+<NUM> + <NUM>). The extent of the overlap between the innermost surface of the closure fold <NUM> and the outermost surface of the body curl <NUM> is in the region of <NUM>, whilst that between the innermost surface of the pip <NUM> and the outermost surface of the body curl <NUM> is in the region of <NUM>. These dimensions allow the closure <NUM> to be easily pressed onto the end of the closure whereupon the pips <NUM> snap in beneath the body curl <NUM> to retain the closure in place.

Equally, only a relatively small force is required to remove the closure. The sloping faces of the pips <NUM> help to reduce the forces required to press on and remove the closure.

It will be appreciated that there is no overlap in a radial sense between the closure fold <NUM> and the peelable lid <NUM>, whilst there is only a very small overlap, in the region of <NUM>, between the pip <NUM> and the lid <NUM>. This, in conjunction with the height of the innermost surface of the pips, means that neither the closure fold <NUM> nor the pip, or indeed any other part of the closure sidewall makes contact with the foil lid during closure and opening. There is therefore minimal risk of the lid being disturbed or damaged during these operations. <FIG> illustrate an alternative container construction and specifically an alternative closure construction. <FIG> show the closure <NUM> comprising a central, circular, panel region <NUM> , and a cylindrical sidewall <NUM> depending from the central panel. The sidewall terminates in an inwardly directed fold that is provided as a hem (or curl) <NUM>. Four equally spaced pips <NUM> are pressed into the sidewall, as are four equally spaced features <NUM>, with the pips and features alternating around the sidewall circumference. In this case the features are beads that may have an angular extent of between <NUM> and <NUM> degrees.

In this construction, the beads <NUM> extend inwardly to a greater radial extent than do the pips <NUM>, such that it is the beads that interfere with the curl <NUM> at the top of the container body <NUM>, and not the pips. This is illustrated by the vertical cross-sections of <FIG>, where <FIG> shows a cross-section through one of the beads, whilst <FIG> shows a cross-section through one of the pips. As indicated, the radial overlap between the curl <NUM> of the container body and the beads <NUM> is <NUM>, whilst the radial spacing (gap) between the curl <NUM> and the pips <NUM> is <NUM>. The total embossed depth of the beads is <NUM> whilst that of the pips is <NUM>. The pips <NUM> of this design provide decorative features as well as reinforcement of the sidewall <NUM>.

Claim 1:
A container (<NUM>) comprising:
a substantially tubular metal container body (<NUM>, <NUM>) having a top opening defined by an outwardly curled edge (<NUM>, <NUM>), and a bottom opening; a lid (<NUM>) bonded to an upper surface of said curled edge (<NUM>, <NUM>) to close said top opening in an airtight manner, the outermost edge of the lid (<NUM>) not extending beyond an outermost extent of said curled edge (<NUM>, <NUM>);
a metal closure (<NUM>, <NUM>) comprising a generally planar centre panel (<NUM>) and a downwardly extending sidewall (<NUM>, <NUM>) depending from a peripheral region of the centre panel and terminating with a fold (<NUM>, <NUM>), and a plurality of features (<NUM>, <NUM>) pressed into the sidewall (<NUM>, <NUM>) at respective circumferentially spaced locations between said peripheral region and the fold (<NUM>, <NUM>), the radial inward extent of the features (<NUM>, <NUM>) is greater than that of the fold (<NUM>, <NUM>), the closure (<NUM>, <NUM>) and the container body (<NUM>, <NUM>) having relative dimensions to allow the features (<NUM>, <NUM>) to pass over said curled edge (<NUM>, <NUM>) during closure and to be retained beneath the curled edge (<NUM>, <NUM>) to resist removal of the closure (<NUM>, <NUM>), characterised in that the lid (<NUM>) is peelable, the fold (<NUM>, <NUM>) is inwardly directed, and in that an innermost radius of the fold (<NUM>, <NUM>) is less than an outermost radius of the outwardly curled edge (<NUM>, <NUM>) of the container body (<NUM>, <NUM>), but said innermost radius lying outside of the innermost extent of the features (<NUM>, <NUM>).