CLOSURE FOR A CONTAINER AND A CONTAINER PROVIDED THEREWITH

Abstract

The present invention relates to a closure for a container, comprising, a tab attached by rivet means to a closure part to be displaced for forming an opening in the closure, which opening is at least partly defined by a score line formed in the closure, the tab comprises a tab body connected to the rivet means, a tab rear part for finger gripping, and a tab front part of which a tab nose is located near or at the score line, such that during a closure opening procedure comprising finger gripping the tab rear part, lifting the tab rear part thereby pressing the tab nose against the closure on or near the score line, popping the score line, and scoring the score line thereby forming an opening in the closure, characterized by score line parts separated by a score line part to be popped by the tab nose, which score line parts are stronger than the popping score line part, and by stiffening means stiffening closure parts neighboring the stronger score line parts, and to a container provided with such closure.

Claims

1. Closure for a container, comprising, a tab attached by rivet means to a closure part to be displaced for forming an opening in the closure, which opening is at least partly defined by a score line formed in the closure, the tab comprises a tab body connected to the rivet means, a tab rear part for finger gripping, and a tab front part of which a tab nose is located near or at the score line, such that during a closure opening procedure comprising finger gripping the tab rear part, lifting the tab rear part thereby pressing the tab nose against the closure on or near the score line, popping the score line, and scoring the score line thereby forming an opening in the closure, characterized by score line parts separated by a score line part to be popped by the tab nose, which score line parts are stronger than the popping score line part, and by stiffening means stiffening closure parts neighboring the stronger score line parts.

2. Closure as claimed in claim 1, wherein the stronger score line parts have a residual thickness (r) which is greater than the residual (rp) thickness of the popping score line.

3. Closure as claimed in claim 2, wherein the residual thickness (r) is in the range of 40-90 μm, preferably of 45-80 μm, such as 50-75 μm.

4. Closure as claimed in claim 2, wherein the difference between r and rp is at least 5 μm, preferably at least 10 μm, or 15 μm, such as in the range of 5-40 μm, preferably 10-35 μm, more preferably 15-30 μm.

5. Closure as claimed in claim 2, wherein the stronger score line part has a length in the range of 5-30 mm, preferably 10-20 mm.

6. Closure as claimed in claim 1, wherein the stiffening means comprise at least one elongated stiffening element elements at both sides of the rivet means, and preferably two or more elongated stiffening elements at both sides of the rivet means.

7. Closure as claimed in claim 6, wherein the elongated stiffening elements are straight.

8. Closure as claimed in claim 7, wherein the straight stiffening elements are parallel to each other at one side of the rivet and preferably the straight stiffening elements are parallel to each other at both sides of the rivet.

9. Closure as claimed in claim 6, wherein the straight stiffening elements converge relative to the straight stiffening elements at the other side of the rivet.

10. Closure as claimed in claim 6, wherein the stiffening elements are curved and/or hooked.

11. Closure as claimed in claim 11, wherein the curved or hooked stiffening elements are concentric, and preferably concentric with the rivet means as the center.

12. Closure as claimed in claim 1, wherein the stiffening means contact or extend beyond the score line.

13. Closure as claimed in claim 1, wherein the closure comprises a groove extending radially inwardly along the score line, and the stiffening means extend into or beyond the groove.

14. Closure as claimed in claim 1, wherein stiffening means comprise at least one stiffening element extending parallel to the score line, and the length (L) of the indentation or projection parallel to the score line is greater than width (W) of the projection or projection, and preferably the ratio of L/W is greater than 1, preferably greater than 1.5, such as in the range of 2-15, preferably 5-10.

15. Container provided with a closure according to claim 1.

16. Container provided with as closure according to claim 14.

17. Closure for a container, comprising a tab attached by rivet means to a closure part to be displaced for forming an opening in the closure, which opening is at least partly defined by a score line formed in the closure, the tab comprises a tab body connected to the rivet means, a tab rear part for finger gripping, and a tab front part of which a tab nose is located near or at the score line, such that during a closure opening procedure comprising finger gripping the tab rear part, lifting the tab rear part thereby pressing the tab nose against the closure on or near the score line, popping the score line, and scoring the score line thereby forming an opening in the closure, characterized by score line parts separated by a score line part to be popped by the tab nose, which score line parts are stronger than the popping score line part, and by stiffening means stiffening closure parts neighboring the stronger score line parts, and wherein the stiffening means comprise at least one elongated stiffening element at each side of the rivet means.

18. Closure as claimed in claim 17, wherein the stiffening means contact or extend.beyond the score line.

19. Closure as claimed in claim 17, wherein the closure comprises a groove extending radially inwardly along the score line, and the stiffening means extend into or beyond the groove.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0035] Mentioned and other features and characteristics of a closure and container according to the present invention will be further elucidated and discussed with reference to the following embodiments which are given for information purposes only without an intention to restrict the invention further. In relation to such a description reference will be made to the figures wherein:

[0036] FIG. 1 shows a perspective view of a closure of the invention;

[0037] FIG. 2 is a top view of the closure of FIG. 1 with the tab and by an interrupted line the opening arc;

[0038] FIG. 3 is the top view of FIG. 2 without the tab;

[0039] FIG. 4 is a cross section along the line IV-IV of FIG. 3, and FIG. 4A and 4B at higher magnification cross sections at the popping score line and at the stronger score line part, respectively;

[0040] FIG. 5 is a top view of a closure of the invention with the longer opening arc of the invention in comparison to the indicated opening arc of FIG. 2;

[0041] FIG. 6 is a top view of the closure of FIG. 5 without the tab;

[0042] FIG. 7 is a perspective view of the underside of the closure of FIG. 5 of the invention;

[0043] FIG. 8 is a perspective view of the closure of the invention of FIG. 5 after opening and forming of the opening chord;

[0044] FIGS. 9-15 are top views according to FIG. 6 of alternative embodiments of the closure of the invention; and

[0045] FIGS. 16 and 17 are top views according to FIG. 6 of alternative embodiments with stiffening elements with increased length in a direction away from the rivet.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0046] FIG. 1 shows a closure 1 of the prior art. The closure 1 comprises a (partially) displaceable closure part 2 to which is attached a tab 3 via a rivet 4. The closure part 2 has a terrace structure 5 defined by terrace steps 6 and a surrounding substantially circular step 7 radially inwardly curved in the region of the rivet 4. The removable closure part 2 is surrounded by a circular score line 8. The score line 8 comprises a popping score line part 8.1 near the nose 36 of the tab 3 and having a residual thickness rp of typically 65 μm and a length of 5 mm, and two stronger score line parts 8.2 having a residual thickness r of 65 μm+30 μm and a length of 13 mm, separated by the popping score line part 8.1 located in the popping area. Along the score line 8 are extending an outer circular groove 9 connected to a curl 10 for connection to a container body (not shown), and an inner circular groove 11 (see FIGS. 2, 3 and 4). The step 7 comprises a curved part 12 thereby providing space for the rivet 4 which is integrally formed from material of the closure part 2. Furthermore, are present dimples 15 supporting the tab 3.

[0047] The closure comprises stiffening means 13 in the form of elongated stiffening elements 14 oriented cross to the groove 11 and the score line 8. At both sides of the rivet 4 there are two straight and parallel stiffening elements 14.1 and 14.2 with a length decreasing in a direction remote of the rivet 4, or in the alternative with a length increasing in the remote direction, see also FIGS. 16 and 17. The stiffening elements have the form of grooves 14 which are open to the tab side of the closure 1. The stiffening elements 14 are connected to, and opened into the groove 11. The stronger score line parts 8.2 extend beyond of the stiffening elements 14.1 and 14.2.

[0048] FIG. 2 shows the opening chord 16 that moved further to the center of the closure due to the presence of the stiffening elements 14 in comparison to the folding line 17 formed in the absence of the stiffening elements 13, when the tab 3 is lifted and the score line broken over the score line arc 18.bounded by the interceptions of the score line 8 with the folding line 17. The tear force for opening the closure 1 when mounted on a container body with a diameter of 73 mm is about 45N.

[0049] FIGS. 5-8 show a closure 19 according to the invention. The same structural elements for this closure 19 which are also present and discussed in relation to the closure 1 are identified with the same reference numbers. Closure 19 comprises a closure part 2 to which is attached the tab 3 via the rivet 4. The closure part 2 has a terrace structure 5 defined by the steps 6 and 7. The terrace structure 5 is surrounded by the step 7. The closure part 2 is delineated by the circumferential score line 8. The grooves 9 and 11 extend at each side of the score line 8 around the score line 8. Also present are curved stiffening elements 18.1-3 extending on hypothetical circles laterally of the rivet 4 and the rivet 4 as the circles centre.

[0050] The closure 19 according to the invention differs from the closure 1, in that stiffening means 13 in the form of curved stiffening elements 18 extend along the rivet 4 towards the score line 8, and close to or in the area between the rivet 4 and the score line 8. The stiffening elements 18 have the form of grooves 18 extending sidewise of the rivet 4 towards the score line 8 and contact the inner groove 11. The effect of the presence of the stiffening elements 18 is, that the area neighboring the score line 8 is stiffer. The popping score line part 37.1 has a residual thickness (rp) of typically 65 μm, and a length of 5 mm, separates the stronger score line parts 37.2 having a residual thickness (r) of 20 μm extra as compared to rp, and a length of 18 mm. The folding line 23 along which is section 25 of the closure part 2 is folded inwardly after popping and scoring the score line 8 at different scoring force due to the presence of the stronger score line parts 37.2, neighbored by the stiffening elements 18.1-3, thereby forming an opening 24, is now transferred more towards the center of the closure 19 such that the opening chord 26 defined in between the intersection of the folding line 23 with the score line 8 is larger than that with the folding line 17 as discussed in relation to FIG. 2.

[0051] It is evident, that due to the presence of three stiffening elements 18 the in the closure 19 according to the invention, that the folding line 23 is transferred more to the center of the closure 19. Accordingly, the opening chord 26 as defined in between the intersections of the folding line 23 with the score line 8 is longer than the opening chord 16 as defined between the intersections of the folding line 17 with the score line 8. With the result that the tear force for opening the closure 19 when mounted on a container body with the diameter of 73 mm is about 45N at about 65 μm residual (rp).

[0052] Hereafter are discussed various embodiments of the invention showing still other different types of stiffening elements according to the invention. The embodiments of the closure 20, 21 and 22 comprise elongated stiffening grooves that contact and open into the inner groove 11 which is parallel to the score line 8.

[0053] As discussed in relation to the FIGS. 5-8, and further shown in detail in FIG. 9, the closure 20 according to the invention comprises elongated and straight stiffening elements 22 extending laterally at both sides of the rivet 4 towards the score line 8 and open into the groove 11. The stiffening elements 26.1-3 are oriented cross to and open into the groove 11. The length of the stiffening elements decreases from the inner stiffening element 26.1 via the stiffening element 26.2, towards the stiffening element 26.3. The change in properties such as strength, in the area of the groove 11 and the score line 8, will result in a stiffening the area neighboring the stronger score line parts 38.2 separated by the popping score line part 38.1, near the stiffening elements 26.1-3, and thus in a stiffening in forming the ultimate opening in the closure 20.

[0054] The closure 21 according to the invention as shown in FIG. 10, comprises the stiffening elements 27 in the form of grooves 27.1-3 according to the invention. The stiffening elements 27 are at both sides mutually parallel, and from both sides of the rivet 4 converge with the stiffening elements 27.1 close to or into the area between the rivet 4 and the groove 11 and the score line 8. This results in stiffening the neighboring area along the stronger score line parts 39.2 separated by the popping score line part 39.1 spanning the popping area in front of the tab (not shown). The closure 21 does not comprise a terrace structure 5, so that the length of the stiffening elements 27 may be extended when appropriate.

[0055] The closure 22 according to the invention as illustrated in FIG. 11 comprises stiffening means 13 which have the form of hooked stiffening grooves 28.1 and 28.2. They extend laterally of the rivet 4 and contacts the groove 11 close to and radially inwardly of the score line 8. These stiffening elements 28 again strengthen the area neighboring the stronger score line parts 40.2 separated by the popping score line part 40.1.

[0056] The closures 29, 30 and 31 shown in FIGS. 12-14 relate to embodiments of the closures of the invention in which the stiffening means contact (FIG. 12) or extend beyond (FIGS. 13 and 14) the score line 8. This is possible because the groove 11, as for instance discussed in relation to the closures of FIGS. 1-11, is not present. Although the skilled person will appreciated that such groove 11 may be present without deteriorating the desired effect of the invention, which is strengthening the area neighboring the stronger score line parts.

[0057] The closure 29 according to the invention as illustrated in FIG. 12 comprises stiffening means 13 according to the invention, having the form of stiffening grooves 32 which extend laterally and parallel of the rivet 4 and converges with the stiffening grooves 32.1 extending (partly) in front of the rivet 4 but are in contact with the score line 8 in the stronger score line parts 41.2 having a greater residual thickness (r) than the residual thickness (rp) of the popping score line part 41.1. The contact of the stiffening grooves 32 with the stronger score line parts 41.2 is accomplished such that the properties of the score line 8 are not negatively affected.

[0058] The skilled person will appreciate, that in an alternative to the embodiment of the closure 30 as shown in FIG. 13, that the stiffening elements 33 have the same form and mutual orientation as the stiffening grooves 32 of the closure 29 of FIG. 12, but the stiffening elements 33 not only contact the score line 8 at the stronger score line parts 42.1 separated by the popping score line part 42.1, but also extend radially outwardly and beyond the stronger score line parts 42.2.Whereby the presence of the stiffening elements 33 is substantially greater than when only contacting the score line 8. But the formation of the contacting and crossing stiffening elements 33.1-3 and the stronger score line parts 42.2 of the score line 8 is delicate but technically feasible because of the residual thickness (r) of the stronger score line parts 42.2. It is noted, as will be appreciated by the skilled person that these stiffening elements 33 may also run in parallel or have a curved or serpentine form and intersect with the score line 8 at different angels. Also a terrace structure 5 may be present.

[0059] The closure 31 of the invention as shown in FIG. 14 comprises concentric partially circular stiffening elements 34.1 and 34.2 extending at both sides of the rivet 4 and extend up to and beyond the stronger score line parts 43.2 of the score line 8. The stiffening elements 34.1 may further than shown extend in the area between the rivet 4 and the popping score line part 43.1 of the score line 8.

[0060] In an alternative embodiment of the stiffening means 13 of the invention as shown in FIG. 15, the stiffening means comprise stiffening elements 35 extending parallel to the stronger score line parts 44.2 of the score line 8, and the length (L) of the indentation or projection parallel to the score line 8 is greater than width (W) of the stiffening elements. Thus, in comparison to the stiffening elements extending cross or radially relative to the score line, these stiffening elements 35 extend along (and preferably parallel) to stronger score line parts 44.2 of the score line 8. The length L is about 10 mm and the width W is about 1.5-3mm. The depth is about0.5 mm. For an optimal stiffening of the speed of scoring it is preferred when these stiffening elements have a form of which the ratio of L/W is greater than 1, preferably greater than 1.5, such as in the range of 2-15, or 5-10.

[0061] The embodiment of the closure 47 of the invention shown in FIG. 16, comprises a central score line part 45.1 separating stronger score line parts 45.2 which are neighbored by stiffening means 13 of which the parallel stiffening elements 46.1 to 46.3 in the direction away from the rivet 4 have the same length. But in an alternative the stiffening elements may increase in length in the direction away from the rivet 4. This results in closure areas remote of the rivet 4 having a relatively high stiffness.

[0062] Similarly, the embodiment of the closure 48 shown in FIG. 17, comprising a central score line part 49.1, separating stronger score line parts 49.2 neighbored by stiffening elements 50.1 to 50.3 increasing in length more remote of the rivet 4. These converging stiffening elements 50.1-50.3 increase the stiffness of the areas neighboring the stronger score line parts 49.2, with stiffness increasing in a direction away from the rivet 4.

[0063] After having discussed the various embodiments of the stiffening means 13 according to the invention for an easy opening closure, it will be appreciated to the skilled person that the score line 8 may extend along the circumference of the closure thereby dividing after tearing out the score closure part 2 the largest opening in the container. However, the score line may also occupy only a part of the closure thereby forming a smaller opening, when the score line is not a closed line only forming an opening as for instance illustrated by the opening 24 as shown in FIG. 8. Evidently, such closure of the invention may also be present in other types of closures than easy opening closures.

[0064] The stiffening means 13 may have the form of stiffening elements being elongated indentations or projections in the closure sidewise of the rivet and extending to inner groove and indirectly to the score line 8 located more radially outwardly of the inner groove, or in absence of the inner groove directly to the score line. In the alternative the stiffening elements may cross and extend beyond the inner groove and at the same time the score line.

[0065] Whether or not the various different types of stiffening means may be present, is dependent on the thickness of the closure, of the material of which the closure is made, such as steel, tin plate, aluminum, metal plastic laminates, and the like. Also the diameter of the closure may be taken into consideration, such as diameters varying from 24 to 240 mm, such as 40 to 180 mm, such as 73 mm. Obviously, the presence of step 7, a terrace structure 5, the presence of dimples and other structures may be taken into consideration by the skilled person when deciding what type of stiffening means (20)? according to the invention are to be used in order to reduce the tear force for opening the container while not or substantially not interfering with other structural elements present in the closure. Also the residing subatmospheric pressure in the container before opening is to be considered in the relation to the type, structure and wall thickness of the closure. For standard metal alloys used the wall thickness may be in the range of 0.12 to 0.24 mm, such as 0.14 to 0.20 mm, like 0.16 mm or 0.18 mm. The distance between neighboring stiffening elements at the same side of the rivet may vary between 2-10 mm, or 2-6 mm, such as 3 mm and 4 mm. The width is generally in the range of 0.2-4 mm, such as 0.5-2.5 mm. The depth is generally in the range of 0.2-2 mm, such as 0.3-1 mm.

[0066] The skilled person will appreciate that the shape and dimensions of the score line and the stiffening elements depend on the dimensions and material of the closure and on the residing subatmospheric pressure.