METAL END PANEL WITH HOLE Technical Field

[0001] The present invention relates to a sheet metal end panel for a container, such as a beverage can, having a hole defined therein, which is adapted to receive a separate closure. The closure is designed to close and seal the hole and may be opened and resealed after each use.

Background Art

[0002] EP 1607341 A (TOYO SEIKAN) 21.12.2005 discloses an end comprising a closure member having an opening, that has been formed in advance and an unsealing tab, which is fitted to the outer surface of the closure member so as to cover the opening. The unsealing tab is hermetically adhered to the periphery of the opening and includes a flexible tab member and a plug member integrally adhered thereto, which is adapted to be fitted to the opening provided in the closure member. The flexible tab member is hermetically fixed to the periphery of the opening in the closure member so as to be torn off upon opening.

[0003] In EP 1607341 A (TOYO SEIKAN) 21.12.2005 , the edge of the opening in the closure member does not have to be flat, since the tab member is flexible and may accommodate any unevenness in the sealing surface. However, the opening has to be positioned sufficiently distant from the edge of the closure member in order to provide a sealing surface of sufficient width to provide a hermetic seal. This distance makes drinking from, and to an extent pouring from, the container difficult.

[0004] The flexible tab member is required because the accuracy of the fit between the plug member and the opening or the smoothness of the surfaces may be insufficient to provide a fluid seal on their own. Once opened, the container may not re-seal, particularly if the contents of the container are pressurised, and leakage of liquid or gas may occur.

[0005] EP 1640282 B (BALL PACKAGING) 27.12.2006 describes a lid for a container, particularly for contents that are held under pressure. The sheet metal lid has a lid panel surrounded by a folded edge. The panel has a large dimensioned opening, into which a separate reclosing device is fitted. The large dimensioned opening affects the stability of the sheet metal lid and thus a stiffening strip and a reinforcement plateau is provided on the lid.

[0006] The provision of such stiffening structures is only possible in the arrangement described in EP 1640282 B (BALL PACKAGING) 27.12.2006 because the separate reclosing device is fixed in the sheet metal lid and is not required to move relative thereto. The lid is opened and reclosed by internal relative movement between parts of the reclosing device, not because of relative movement between the reclosing device and the sheet metal lid panel. Also, the reclosing device obstructs the majority of the opening, preventing for example the use of a drinking straw.

[0007] WO 2007/128810 15.11.2007 filed by the present applicants, describes a metal can end into which a plastic opening device is fitted and the plastic opening device is arranged to slide relative to an aperture in the metal end panel to open and reclose the aperture. The opening device described in WO 2007/128810 15.11.2007 cannot be applied to the end panel previously described in the prior art, because the sliding path taken by the opening device relative to the metal end panel needs to be unimpeded. Also, the aperture in the metal end panel needs to be designed to provide a smooth sealing surface, against which the separate opening device forms a fluid-tight seal.

Disclosure of Invention

[0008] The present invention provides a sheet metal lid for closing a container body, the lid comprising a centre panel surrounded by a seaming portion adapted to be joined to the periphery of a container body, the centre panel defining an aperture through which the contents of the container may be dispensed, the peripheral edge of the aperture finished by a curl and the aperture adapted to receive a separate closure, characterised in that the closure moves relative to the centre panel between a closed position, in which the aperture and the closure together form a fluid-tight seal, and an open position, in which the seal is broken and the closure slides across the surface of the centre panel to open at least part of the aperture.

[0009] The invention provides a metal end panel with a hole that can be made rounder, flatter and closer to the panel edge. The edge of the aperture is curled to protect a user from the cut edge of the aperture and the curl provides a stiffened aperture with accurate, smooth sealing surfaces. The end panel is adapted to receive a separate closure, which moves between a closed and an open position. In its closed position, the closure occludes the aperture and forms a fluid-tight seal with the edge of the aperture.

[0010] Upon opening, the closure slides across the surface of the end panel to expose a major part of the aperture, through which the contents of a filled container onto which the end panel and a separate closure is applied, may be poured or drunk or through which a straw may be inserted. The end panel of the invention is particularly suited to a moveable closure device such as that described in WO 2007/128810 15.11.2007 . Preferably, the aperture curl is recessed into the plane of the end panel allowing the closure device to be moved across the end panel, away from the aperture, without impedance from the aperture curl into the path of the closure device as it moves to its open position.

[0011] The end panel is suitable for fixing to a can end or a can body. Sealing is achievable against the bottom of the aperture curl, inside the curl or on the outside portion of the underside of the curl. The curl may depend upwards or downwards from the end panel.

Brief Description of Figures in the Drawings

[0012] The present invention will now be described, by way of example only, with reference to the attached drawings, in which:

[0013] Figure 1 is a plan view of an end shell according to the invention;

Figure 1A is a cross section view of the end shell shown in figure 1 taken along the line A-A;

Figure 1 B is a detailed portion of the cross section view of figure 1A, indicated by circle B, showing a curl around the perimeter of the aperture in the end shell;

Figure 1C is portion of the cross section view of figure 1A, indicated by circle C, indicating the distances between various features of the end shell.

[0014] A step wise progression, method and tooling used to form the final can end is also described, by way of example only, with reference to the attached drawings, in which:

Figure 2 is an perspective view of a plain end shell blank, which is pressed from metal sheet;

Figure 2A is a plan view of the end shell blank illustrated in figure 2;

Figure 2B is a side cross section view of the end shell blank illustrated in figure 2A taken along the line A-A;

Figure 3 is an perspective view of the end shell blank having a hole punched through the planar centre panel thereof;

Figure 3A is a plan view of the end shell blank illustrated in figure 3;

Figure 3B is a side cross section view of the end shell blank illustrated in figures 3 and 3A, with an inset detailed view of the portion indicated by the letter B;

Figure 4A illustrates tooling suitable for forming a depression around the periphery of the hole in the end shell blank, in a start position, in which the end shell blank is clamped in position and no depression has been formed yet, with an inset detailed view of the portion indicated by the letter D;

Figure 4B illustrates the same tooling as illustrated in figure 4A, in a finish position, in which an annular punch has formed a depression around the periphery of the hole in the end shell blank;

Figure 5 is an perspective view of the end shell blank having a hole punched through the planar centre panel thereof and a depression formed around the periphery of the hole;

Figure 5A is a plan view of the end shell blank illustrated in figure 5;

Figure 5B is a side cross section view of the end shell blank illustrated in figures 5 and 5A, with an inset detailed view of the portion indicated by the letter B;

Figure 6A illustrates tooling suitable for drawing the raw edge of the hole into the start of a curl, in a start position, in which the end shell blank is clamped in position and no drawing has yet taken place, with an inset detailed view of the portion indicated by the letter E;

Figure 6B illustrates the same tooling as illustrated in figure 6A, in a finish position, in which a draw punch has been moved through the hole thereby forming the start of a curl, with an inset detailed view of the portion indicated by the letter E;

Figure 7 is a perspective view of the end shell blank having a hole punched through the planar centre panel thereof and the start of a curl formed around the periphery of the hole;

Figure 7A is a plan view of the end shell blank illustrated in figure 7;

Figure 7B is a side cross section view of the end shell blank illustrated in figures 7 and 7A, with an inset detailed view of the portion indicated by the letter B;

Figure 8 is a perspective view of the finished end shell having a hole punched through the planar centre panel thereof and a curl formed around the periphery of the hole;

Figure 8A is a plan view of the finished end shell illustrated in figure 8;

Figure 8B is a side cross section view of the finished end shell illustrated in figures 8 and 8A, with an inset detailed view of the portion indicated by the letter B;

Figure 9 illustrates a first example of tooling suitable for converting the

"start of a curl" shown in figures 7 to 7B, to create a curl, in which the end shell blank is interposed between a coin punch and a coin die which are suitably shaped to coin the final shape and dimensions of the curl;

Figure 10 illustrates a second example of tooling suitable for converting the "start of a curl" shown in figures 7 to 7B, to create a curl, in which the

"start of a curl" is supported in a coin die, which is suitably shaped to control the dimensions of the curl formed around the periphery of the hole, when the coin punch is brought into contact with the coin die;

Figure 11A illustrates a third example of tooling suitable for converting the

"start of a curl" shown in figures 7 to 7B, to create a curl, in a start position, in which the coin punch and coin die are spaced apart. This tooling is an enhancement of the tooling illustrated in figure 10, in which the end shell blank is placed in the coin die and a clamp is applied around the edge of the hole;

Figure 11 B illustrates the tooling shown in figure 11A in a finish position, in which the coin punch has been brought into contact with the coin die, forming a curl of controlled dimensions around the periphery of the hole. [0015] Referring to Figures 1. 1A. 1 B and 1C. a can end 1 according to the invention has a hole 7 through which the contents of the can (not shown in the figures), to which the can end 1 is affixed, may be dispensed from the can by a user and then the can may be closed and re-sealed. The hole is adapted to receive a separate closure (not shown) which may be moved relative to the can end 1 between a closed position, in which the hole 7 is closed and sealed, and an open position, in which the hole or a major portion thereof is exposed allowing the contents of the can to be dispensed. The can end 1 is fixed to a can body (not shown) using conventional joining techniques, such as double seaming etc.

[0016] Referring to figure 1C in particular, W of the can end 1 according to the invention is less than 4mm, preferably less than 3mm. (In the end described in EP 1607341 A (TOYO SEIKAN) 21.12.2005 currently on sale, W is approx. 4mm.) X is preferably less than 3mm.

[0017] A method and apparatus for producing such an end panel is also described by way of example. This has fewer steps than described and shown in any of Figs. 33, 34, 35 and 36 in EP 1607341 A (TOYO SEIKAN) 21.12.2005 .

[0018] Figures 2 through 8 show a stepwise progression of the formation of the end shell 1 ' culminating in a finished can end 1 and the tooling required to complete each step in the fabrication.

[0019] Method Steps:

The first step of the method is to pierce a hole 7 through the end shell blank V as shown in figs 3. 3A and 3B. This step may be carried out using a conventional punch and die arrangement, and the end panel may be clamped against the face of the die during piercing. The metal disc created in the piercing step may be discarded or may be saved for another purpose.

[0020] The second step of the method is to depress an annular region 8' around the periphery of the hole 7 as shown in figs 4A. 4B. 5. 5A and 5B In the tooling of figure 4A. the hole 7 is positioned on a location tool 35 before being clamped between the opposing faces of the clamp 40 and die 30. The annular region 8' is then depressed into the annular profile of the die 30 by the movement of the annular punch 45.

[0021] Preferably, the periphery of the hole 7 is formed into a lip 9 by drawing it between the inner diameter of the annular punch 40 and the inner wall of the annular profile of the die 30. The lip 9 assists smooth forming of the curl in the final step.

[0022] The radius between the outer diameter and the end face of the annular punch 45, the radius between the outer wall of the annular profile and the adjacent face of the die 30, and the depth of the annular region 8' approximate to the desired final dimensions of the curl. This avoids excessive working or re-working of the metal, and helps to preserve the surfaces to provide sealing in subsequent use.

[0023] Formation of the annular region 8' helps to remove any slackness of the metal in the end panel, and helps to stiffen the periphery of the hole 7.

[0024] Whilst it is preferred to carry out the first step of piercing and the second step of forming the depression separately as described above, it is possible to combine these two steps into one, to reduce the overall number of steps required. For example this can be done by removing the location tool 35 from the tooling of figures 4A and 4B. providing a cutting edge in a modified version of the die 30 and providing a piercing punch. With such tools it is possible to sequentially clamp the end panel, then pierce a hole and then form an annular depression.

[0025] The third step of the method is to draw the inner portion of the annular region 8' upwards using the tooling of figures 6A and 6B to form the "start of a curl" 8" shown in figures 7 to 7B.

[0026] In the tooling of figure 6A, the end panel is firstly clamped between the faces of the die 60 and clamp 70, and the outer portion of the annular region 8' is supported by the profile of the die 60. The inner portion of the annular region 8' is then formed into the "start of a curl" 8" by movement of the punch 50.

[0027] The profile of the die 60 approximates to the desired final internal dimensions of the curl. This avoids excessive working or re-working of the metal, and helps to preserve the surfaces to provide sealing in subsequent use. [0028] Whilst it is preferred to carry out this third step of forming the "start of a curl" 8" between forming the annular depression 8' and the final step of creating the final curl, it is possible to omit this third step. Omission of this third step is possible if the inside diameter of the lip 9 approximates to the final inside diameter of the curl, and the height of the lip 9 is tall enough to form into the final curl. The height of the lip 9 may be made tall by providing the die 30 with an inner face positioned above the outer face.

[0029] The final step of the method is to form the final shape of the curl using tooling arranged to accurately control the dimensions and condition of those surfaces against which the closure is to subsequently fit and seal.

[0030] The tooling of figure 9 shows a punch 80 and a die 90 in a closed position. The curl 8 has been formed to a final shape and dimensions by the profiles of the punch 80 and die 90.

[0031] The tooling of figure 10 shows an alternative punch 80' and an alternative die 90', in a closed position. The curl 8 has been formed to a final shape and dimensions by the alternative profiles of the punch 80' and die 90'

[0032] Either the tooling of figure 9 or the tooling of figure 10 may be preferred depending upon which surfaces of the curl 8 are to be used to fit and seal against the closure (not shown), and so are important to be supported by the tooling profiles.

[0033] The tooling of figures 11A and 11 B shows an improved version of the tooling of figure 10. Figure 11A shows the end panel clamped between a die 90" and an annular clamping ring 85, and figure 11 B shows the same tooling after a punch 80" has been moved to form the final curl 8. Clamping the end panel in this way prevents the metal of the curl being pushed outwards from the profile of the die during forming, and so produces a better curl and prevents slackness being created in the metal of the panel surrounding the aperture.

[0034] The punch 80" of figures 11A and 11 B has a downward projection at the periphery of its profile, which directs the cut-edge of the curl downwards to reduce exposure of the cut-edge.

[0035] The method described above avoids excessive working of surfaces that are required for sealing, and the progressive formation of annular features prevents the formation of radial wrinkles and the risk of radial splits in the metal. Although the method is described in detail for producing accurate, round apertures for sealing with separate round closures, it will be apparent to the person skilled in the art how this method may be adapted to produce accurate, non-round apertures if desired. The invention has been described as it relates to the formation of a curled aperture in a sheet metal end panel, which is adapted to be joined to a container body. Of course, the metal of the end panel may be coated with polymer or other material and an advantage of the method of the invention is the preservation of such coatings. Of course it is also possible for the aperture of the invention to be formed in the opposite end panel of a sheet metal container body.