Abstract
A panel for a container includes an outer edge to be connected to the container and a tab connected to the panel. The tab has a rear tab part for gripping by a user and a front tab part for engagement with the panel and forming an opening in the panel. The panel is provided with deformation means which structurally deform upon a transition of the panel into a convex shape and which locked in the deformed state urge the panel to a substantially flat or concave shape.
Claims
1. A panel for a container, comprising an outer edge for connection to the container and a tab connected to the panel, wherein the tab has a rear tab part for gripping by a user and a front tab part for engagement with the panel and forming an opening in the panel, wherein the panel is provided with deformation means, which structurally and substantially plastically deform upon a transition of the panel into a convex shape due to a pressure difference over the panel and which, locked in the deformed plastic state, urge the panel to a substantially flat or concave shape, wherein the deformation means are located between a central panel portion of the panel and the outer edge of the panel such that the deformation means are located at least one of a) laterally of the tab; b) diametrically opposed to the tab relative to the central panel portion; and c) annularly around the central portion of the panel with an interruption created by the tab, and wherein, upon the convex transition of the panel, a finger access is formed beneath a free end of the tab and the finger access is maintained when the panel is urged by the deformation means to the substantially flat or concave shape.
2. The panel according to claim 1, wherein the deformation means are located in at least a flexible region of the panel.
3. The panel according to claim 2, wherein the deformation means are located in a substantially circumferential flexible region of the panel.
4. The panel according to claim 1, wherein the deformation means have the form of at least one of the following: a broader terrace step, a radially inwardly inclined terrace, a radially inwardly declined terrace and/or a radially inwardly wavy terrace.
5. The panel according to claim 1, wherein the transition from the convex shape into the flat or concave shape occurs at pressure difference over the panel in the range of about 0.3 bar to +0.3 bar.
6. The panel according to claim 1, wherein the tab rear part rests on a support formed in the panel.
7. A container provided with a panel according to claim 1.
8. The container according to claim 7, wherein the panel has a concave shape and the deformation means are locked in the deformed state.
9. The panel according to claim 1, wherein the transition from the convex shape into the flat or concave shape occurs at pressure difference over the panel in the range of about 0.2 bar to +0.2 bar.
10. The panel according to claim 1, wherein the transition from the convex shape into the flat or concave shape occurs at pressure difference over the panel in the range of about 0.1 bar to +0.1 bar.
11. The panel according to claim 2, wherein the deformation means have the form of at least one of the following: a broader terrace step, a radially inwardly inclined terrace, a radially inwardly declined terrace and/or a radially inwardly wavy terrace.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIGS. 1A, 1B, 1C are cross section views of the various shapes of a panel of the invention;
(2) FIGS. 1D and 1E are side views of the convex shape and the concave shape of the panel of FIG. 1A;
(3) FIG. 2 is a schematic view of schematically a function of the deformation means of the present invention;
(4) FIGS. 3A and 3B are graphical presentations of the panel displacement D as a function of the pressure difference ;
(5) FIGS. 4A, 4B, and 4C are plan views of a panel according to the invention with the preferred locations for the deformation means of the invention;
(6) FIGS. 5A and 5B are graphical presentations relating to the invention;
(7) FIGS. 5C and 5D are further views of another embodiment of the invention;
(8) FIGS. 6A, 6B, and 6C are further views of a further embodiment of the invention; and
(9) FIG. 7 is a cross section view of still another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(10) FIG. 1 shows a panel 1 of the invention. The panel 1 has an outer edge to be connected to the body wall of a container, and a tab 3. The outer edge 2 is connected via a countersink wall 4 and a countersink 5 to a central panel part 6. The tab 3 has a front tab part 7 for engagement with the panel part 6 and for forming an opening in the panel 1 along a score line (not shown). The rear tab part 8 is intended for grasping by the user and for pivoting the front tab part 7 towards the panel 1. The panel 1 has a substantially flat shape. As shown the rear tab part 8 is laterally positioned or the central panel 10. Obviously the rear tab part may also extend over the central panel 10. The panel mid part 10 forms the lowest panel structure. Between this panel mid part 10 and the countersink 5 is a flexible region in the panel 1 which may flex between the shown shape and a more convex shape upon a pressure difference over the panel 1 when mounted on the container or on a testing device.
(11) As shown in FIG. 1A there is in this embodiment diametrically relative to the tab 3 a panel region 11 enclosed by the dashed line 12. This panel region 11 has a shape such that upon application of a pressure difference the panel will be transitioned to the state and shape shown in FIG. 1B. The central panel part 6 is also deformed and has a substantially convex shape. According to the invention, the panel region 11 is an embodiment of deformation means 15 that structurally deform (as shown). The originally concave shape 13 of the panel region 11 is transformed into a convex shape 14 (compare FIGS. 1A and 1B). This transformation into the deformed state is in this case a locked deformed state and thus permanent. This means that after release of the pressure difference the panel region 11 maintains the convex shape.
(12) With the formation of the convex shape of the panel 1 is also formed an larger finger access 31 beneath the rear tab part 8. This larger finger access 31 is maintained when, after pressure release the panel 1 retakes its almost original form and shape. Upon pressure increase, as shown in FIG. 1B some more finger-access 31 is formed because the rear tab part 8 goes up more than the central part of the panel. But when the pressure is released the finger-access 31 goes back to substantially the original position, and it is with a small pressure difference according to the invention that the panel 10 flips in concave position to give the larger finger-access 31. However, the deformation means 15 remain in the deformed state having the convex shape 14. In addition, the panel mid part 10 extends beyond the line 9 and thus beyond the original confinement.
(13) FIG. 1D shows the convex shape of the panel 1 in the region 11 where the deformation means 15 are incorporated in the central panel part 6. As shown in FIG. 1E the deformation means 15 in the panel region 11 have a step 16 between the inner terrace 17 and the radially more outer terrace 18 which has in the panel region 11 a smaller slope than outside this region 11.
(14) The effect of the present invention on relation to the deformation means may be explained by reference to the schematic drawing in FIG. 2, but the possible theory is not binding on the effect of the invention and is solely explanatory. In FIG. 2 the walls 19 illustrate the walls of the container to which the panel 20 is secured. The panel 20 has a circumferential relatively stationary ring panel part 21. Enclosed is the relatively dynamic or flexible panel part 22. Not show in both panel parts 21 and 22 are flexible or harmonica parts formed by for instance the countersink and the terraces, respectively. This deformation urges the panel 20 into a concave shape (not shown). It will be understood that is transition or flipping requires a small or even no force at all, and thus no negative pressure difference.
(15) As is shown in FIG. 3 for illustrative purposes only, the panel having in the starting position the concave shape moves (upon pressure increase) along the line 23. Then at a certain positive pressure difference (pressure development in the closed container) the panel transitions or flips into the convex shape. Upon cooling de displacement D decreases slightly along the line 24. Then at a slightly negative pressure (about 0.1 bar) the panel flips back to the concave shape. The panel as shown may take its starting form as shown or takes a slightly distorted shape. In both cases the deformation means 15 are locked in the deformed state, resulting in the required very small (negative) pressure difference required for the transition back to the concave shape. FIG. 3B shows the same mechanism but the transition already takes place at a small positive pressures difference (about +0.1 bar). It is noted, that during the manufacture and the supply, the panel generally may be in a convex position, and that during processing, such as dependent on the cooking conditions, the panel may shift between a convex and concave position one time or several times. Ultimately, the panel will be in the shape determined by the pressure difference.
(16) FIGS. 4A, 4B, and 4C show the various locations where according to the invention the deformation means are preferably arranged.
(17) In FIG. 4A are the deformation means arranged laterally of the tab 3 and as a further option or in the alternative diametrically of the tab 3. As discussed the deformation means 15 are exemplified to take the form of a broadened of the step 16 between the terraces 17 and 18. Other forms of the deformation means are possible (as discussed hereafter) and other locations circumferentially or radially are possible. These local deformations are preferred as they are in regions where pleats and bulges may form under overpressure and easy to form during panel manufacture.
(18) FIG. 4B shows the deformation means 15 located beneath the tab 3. This is advantageous for situations where the deformation is relatively visible for the customer but shielded at least partly by the tab 3.
(19) FIG. 4C shows the deformation means 15 in an interrupted annular over the region which has the highest flexibility and vulnerability for deformation. The interruption is near the tab 3, so that there is a minimum interference with the tab function.
(20) FIGS. 5A and 5B show more in detail an embodiment of the deformation means 15 of the invention in the panel 29. In FIG. 5A the step 16 between the terraces 18 and 17 is relatively steep and thus rigid or resistant to deformation. In FIG. 5B is the step 16 broader and thus less stiff and more prone to deformation. The deformation is structurally permanent as it is the result of a plastic deformation as shown by the dashed lines 23 and 23 in the FIGS. 5A and 5B.
(21) FIGS. 5C and 5D show a panel 24 according to the invention wherein the deformation means 15 of the invention are located sidewise of the tab 3 and have the form of broadened steps 25 adjacent the smaller step part 26.
(22) FIG. 6A shows another embodiment of the deformation means 15 of the invention incorporated in the panel 28. In this embodiment the step is relatively broad and the radially more inward terrace 27 has an inclined or even dome shape. As in the embodiment of FIG. 4A the deformation means 15 are located adjacent to the tab 3.
(23) In comparison to FIG. 6A, FIG. 7 shows another embodiment of the deformation means 15 of the invention. The step 16 is broadened and the more radially inward terrace 30 has a wavy form. Still upon a pressure difference the deformation means 15 will deform and in the maintained deformed state after pressure reduction will urge the panel of the invention into a flat or concave shape.
(24) As discussed above the relatively small negative or even positive pressure difference at which the panel with the deformation means in the deformed state will transition or flip into the concave shape is in the order of about 0.2 to +0.2 bar or even less. This provides an elegant panel that retakes its concave shape without the need of a larger negative pressure or additional mechanical impact from the outside. The deformation is substantially plastic indicating that the deformation is substantially permanent whereby the transition to the concave shape almost always will take place without.
(25) The panel and the container may be made of any suitable metal such as aluminium, steel, tin plate and mixtures thereof. The panel may have any traditional shape as long as the implementation of the deformation means is possible. The panel and the container may be of any suitable diameter, such as up to 99 mm.
(26) Finally, containers provided with a panel of the invention may be filed with liquid, paste like or solid material, such as pet food and beverages. Still traditional equipment for subjecting the filled and closed container to a heat treatment may be used.
