Container lid

Abstract

Provided is a novel container lid in which a pair of scores 18a and 18b are hard to break when the lid is attached to a mouth neck part 100 of a container, while the pair of scores 18a and 18b are easy to break when the mouth neck part 100 of the container is opened. Remaining material thicknesses of lower parts 18a-1x and 18b-1x of first parts 18a-1 and 18b-1 of the pair of scores 18a and 18b, respectively, are set to be relatively thick, and upper ends of the lower parts 18a-1x and 18b-1x are positioned near an upper end of an extension part 22 of a gripping piece 6.

Description

Container lid

[0001] The present invention relates to a container lid, particularly a container lid for a container having a neck portion in which an annular locking projection protruding radially outward is formed at the upper end of the outer peripheral surface.

[0002] As disclosed in Patent Document 1 below, which was previously filed by the applicant of the present application and has already been patented, as a container lid for a container having a neck portion in which an annular locking projection protruding radially outward is formed at the upper end of the outer peripheral surface, a container lid comprising a metal thin plate shell and a synthetic resin gripping piece has been widely used in practice. The metal thin plate shell has a circular top wall, a skirt wall hanging down from the periphery of this top wall, and a connecting piece extending from the lower end of the skirt wall in a predetermined region in the circumferential direction. A pair of scores are formed on both sides of a predetermined region on the skirt wall and the top wall, extending upward from the lower end of the skirt wall and then extending on the top wall. Each of the pair of scores has a first portion extending upward from the lower end of the skirt wall. The gripping piece has a connecting portion that at least partially surrounds the connecting piece of the metal shell, an extending portion extending upward along the inner peripheral surface of the skirt wall from the upper end of the inner surface of the connecting portion, and a gripping portion extending downward from the connecting portion. Such a gripping piece is connected to the connecting piece of the shell simultaneously with molding by injection molding or compression molding of the synthetic resin material with the connecting piece of the shell as a so-called core. And the container lid as described above is fitted onto the neck portion of the container and is attached to the neck portion by deforming the lower end portion of the skirt wall radially inward and locking it to the locking projection of the neck portion.

[0003] Japanese Patent No. 6576772

[0004] Thus, in the container lid shown in Patent Document 1 above, when the gripping piece is injection molded or compression molded from a synthetic resin material with the connecting piece of the shell as a so-called core, the molding pressure of the synthetic resin material forming the extending portion presses the skirt wall and the connecting piece of the shell radially outward, and the first portion of each of the pair of scores is abused, so that when the container lid is attached to the neck portion of the container, the first portion of each of the pair of scores may unexpectedly break. On the other hand, from the viewpoint of the easy opening property of the container lid, it is desirable that the pair of scores are easily broken when opening.

[0005] The present invention has been made in view of the above facts, and its main technical problem is to provide a novel and improved container lid in which each of the pair of scores is difficult to break when attached to the neck of the container, but each of the pair of scores is easily broken when opening the neck of the container.

[0006] As a result of diligent research, the inventors have found that the main technical problem can be solved by making the residual material thickness at the bottom of the first portion of each of the pair of scores relatively thick, and by positioning the upper end of the lower portion near the upper end of the extension of the gripping piece.

[0007] That is, according to the present invention, as a container lid that solves the above main technical problem, a container lid for a container having a neck portion having an annular locking projection projecting radially outward at the upper end of the outer peripheral surface, the container lid having a circular top wall, a cylindrical skirt wall hanging down from the periphery of the top wall, and a connecting piece extending from the lower end of the skirt wall in a predetermined region in the circumferential direction, the skirt wall and the top wall having a pair of scores formed on both sides of the predetermined region, extending upward from the lower end of the skirt wall and then extending along the top wall, each of the pair of scores comprising a metal sheet shell having a first portion extending upward from the lower end of the skirt wall, and a synthetic resin gripping piece connected to the connecting piece, the container lid including a connecting portion that at least partially surrounds the connecting piece, an extending portion that extends upward from the upper inner surface of the connecting portion along the inner peripheral surface of the skirt wall, and a gripping portion that extends downward from the connecting portion, A container lid is provided, characterized in that the material residue thickness at the bottom of each of the pair of scores is relatively thick, and the upper end of the bottom is located near the upper end of the extension of the gripping piece.

[0008] Preferably, when fitted onto the neck and pressed downward against the neck, the upper end of the extension of the gripping piece is positioned opposite the outer circumferential surface of the locking projection of the neck, and the lower part of the first portion of each of the pair of scores is positioned opposite the outer circumferential surface of the locking projection of the neck, and in this state, the lower end of the skirt wall is crimped radially inward below the locking projection of the neck, so that the upper end of the extension of the gripping piece is sandwiched between the inner circumferential surface of the skirt wall and the outer circumferential surface of the locking projection and attached to the neck. Preferably, each of the pair of scores is formed on the inner surface of the shell. Preferably, the extension of the gripping piece has a trapezoidal shape with a circumferential width decreasing upward. Preferably, the gripping piece is molded from a hard synthetic resin having a Shore D hardness of 55 to 73. Preferably, the shell is formed from an aluminum-based alloy sheet.

[0009] In a container lid constructed according to the present invention, the residual material thickness at the bottom of each first portion of a pair of scores is relatively thick, and therefore the lower portion has sufficient strength, and the upper end of the lower portion of the first portion is located near the upper end of the extension of the gripping piece. Therefore, when the gripping piece is injection molded or compression molded from a synthetic resin material with the connecting piece of the shell as a so-called core, even if the skirt wall of the shell or the connecting piece is pressed radially outward by the molding pressure of the synthetic resin material forming the extension and the first portion of each of the pair of scores is abused, the breakage of each first portion of the pair of scores when attached to the neck of the container is prevented as much as possible. On the other hand, the residual material thickness of the remaining portion of each first portion of a pair of scores, excluding the lower portion, is relatively thin and therefore easily breakable. Therefore, in a container lid constructed according to the present invention, each of the pair of scores is difficult to break when attached to the neck of the container, but each of the pair of scores is easy to break when opening the neck of the container.

[0010] It should be noted in advance that Patent No. 7544478 (hereinafter referred to as the "Reference Publication"), which was filed prior to this application by the applicant of the present application and has already been granted a patent, shows a container lid similar to the container lid shown in Patent Document 1 (hereinafter referred to as the "Reference Container Lid"). The shell of the Reference Container Lid also has a pair of scores formed on it, and the material residue thickness at the bottom of the first portion of each of the pair of scores is relatively thick. The Reference Publication further shows that when the Reference Container Lid is sealed at the neck, the upper end of the lower part of the first portion with the relatively thick material residue thickness is positioned opposite the outer circumferential surface of the locking projection of the neck. However, the gripping piece of the Reference Container Lid does not have an extension that extends upward from the upper end of the inner surface of the connecting portion along the inner circumferential surface of the skirt wall, and the Reference Container Lid does not have any of the problems that the present invention aims to solve. The positional relationship between the lower part, where the residual material thickness in the first portion of each of the pair of scores formed on the shell is relatively thick, and the extension of the gripping piece is not shown in either Patent Document 1 or the Reference Publication.

[0011] A perspective view showing a preferred embodiment of a container lid constructed according to the present invention in an upright position. A perspective view showing the container lid shown in Figure 1 in an inverted position. A cross-sectional view of the container lid shown in Figure 1 along line III-III. A cross-sectional view of the container lid shown in Figure 1 along line IV-IV. A diagram showing the container lid shown in Figure 1 fitted over the neck of the opening. A diagram showing the container lid pressed downward against the neck of the opening from the state shown in Figure 5. A diagram showing the lower end of the skirt wall deformed radially inward from the state shown in Figure 6.

[0012] The following will be a more detailed description with reference to the accompanying drawings showing preferred embodiments of the container lid constructed according to the present invention.

[0013] Referring to Figures 1 to 4, the illustrated container lid, which is shown as number 2 overall, comprises a metal sheet shell 4 and a synthetic resin gripping piece 6.

[0014] The shell 4 is composed of a circular top wall 8, a cylindrical skirt wall 10 hanging down from the periphery of the top wall 8, and a connecting piece 12 extending from the lower end of the skirt wall 10 in a predetermined region in the circumferential direction. Such a shell 4 is integrally formed by applying appropriate machining processes such as punching and drawing to an appropriate metal sheet such as an aluminum-based alloy sheet, a chromic acid-treated steel sheet, or a tinplate sheet. Referring mainly to Figures 3 and 4, the top wall 8 extends substantially horizontally. The skirt wall 10 has an arc-shaped portion 10a that extends radially outward and downward in the longitudinal cross-sectional view, i.e., in Figures 3 and 4, from the periphery of the top wall 8, and a straight portion 10b that extends vertically downward following the arc-shaped portion 10a. In the illustrated embodiment, the longitudinal cross-sectional shape of the arc-shaped portion 10a is a circular arc shape. In this embodiment, the outer diameter of the skirt wall 10 is 27.0 mm, and the axial height is 7.0 mm. The connecting piece 12 has a vertical portion 12a that extends substantially vertically downward from the lower end of the skirt wall 10 and an inclined portion 12b that extends radially outward and downward following the vertical portion 12a. Notches 16a and 16b are formed at the lower end of the skirt wall 10 on both sides of the predetermined area where the connecting piece 12 is provided.

[0015] A pair of scores 18a and 18b are formed on the inner surfaces of the skirt wall 10 and the top wall 8, extending from the notches 16a and 16b, respectively. If desired, the pair of scores 18a and 18b may also be formed on the outer surfaces of the skirt wall 10 and the top wall 8. Each of the pair of scores 18a and 18b has a first portion 18a-1 and 18b-1 that extends from the lower end of the skirt wall 10 to the upper end of the skirt wall 10 following the notches 16a and 16b, a second portion 18a-2 and 18b-2 that extends along the periphery of the top wall 8 following the first portion 18a-1 and 18b-1, and a third portion 18a-3 and 18b-3 that extends further into the skirt wall 10 following the second portion 18a-2 and 18b-2 (see Figure 3). In the container lid of the present invention, it is important that the residual material thickness of the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 of the pair of scores 18a and 18b is relatively thick, and that the upper ends of the lower parts 18a-1x and 18b-1x are located near the upper end of the extension portion 22 of the gripping piece 6, which will be described later. In the illustrated embodiment, the upper ends of the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 of each of the pair of scores 18a and 18b are located at the upper end of the straight portion 10b. If t1 is the material thickness of the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 in each of the pair of scores 18a and 18b, t2 is the material thickness of the remaining portions 18a-1y and 18b-1y of the first portions 18a-1 and 18b-1, and t3 is the material thickness of the second portions 18a-2 and 18b-2 and the third portions 18a-3 and 18b-3, then t1 > t2 > t3. For example, if the thin metal sheet is an aluminum-based alloy with a thickness of 0.24 mm, it is preferable that t1 is approximately 180 to 220 μm, t2 is approximately 145 to 185 μm, and t3 is approximately 100 to 140 μm.

[0016] Continuing the explanation with reference to Figures 1 to 4, the gripping piece 6 includes a connecting portion 20 that at least partially surrounds the connecting piece 12 of the shell 4, an extension portion 22 that extends upward from the upper inner surface of the connecting portion 20 along the inner circumferential surface of the skirt wall 10, and a gripping portion 24 that extends downward from the connecting portion 20. In the illustrated embodiment, the connecting portion 20 surrounds most of the inclined portion 12b of the connecting piece 12 of the shell 4. The extension portion 22 extends in an arc shape in the circumferential direction along the inner circumferential surface of the skirt wall 10. The circumferential length of the extension portion 22 gradually decreases upward, and the extension portion 22 as a whole has a trapezoidal shape. In this embodiment, the thickness of the extension portion 22 is 0.3 mm, the circumferential length of the upper edge is 8.1 mm, the circumferential length of the lower edge is 11.9 mm, the vertical length (axial height) is 5 mm, and the circumferential distance between the first portion 18a-1 of score 18a and the first portion 18b-1 of score 18b is 13.4 mm. The extension portion 22 extends between the first portion 18a-1 of score 18a and the first portion 18b-1 of score 18b. As described above, the upper ends of the lower parts 18a-1x and 18b-1x, which have a relatively thick residual material thickness of t1 in each of the first portions 18a-1 and 18b-1 of the pair of scores 18a and 18b formed on the shell 4, are located near the upper end of the extension portion 22 of the gripping piece 6. The connecting portion 20 of the gripping piece 6 is bonded to the connecting piece 12, but it is preferable that the extended portion 22 of the gripping piece 6 is not bonded or is weakly bonded to the inner circumferential surface of the skirt wall 10.

[0017] Such a gripping piece 6 is connected to the connecting piece 12 of the shell 4 at the same time as molding by injection molding or compression molding from a suitable synthetic resin material such as polypropylene or polyethylene, preferably a synthetic resin with a Shore D hardness of 55 to 73, with the connecting portion 20 as a so-called core. When the gripping piece 6 is injection molded or compression molded from the synthetic resin material with the connecting piece 12 of the shell 4 as a so-called core, the molding pressure of the synthetic resin material forming the extension portion 22 presses the skirt wall 10 of the shell 4 to the connecting piece 12, and more specifically its vertical portion 12a, radially outward, thereby damaging the first portions 18a-1 and 18b-1 of the pair of scores 18a and 18b. At this time, the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 tend to be significantly damaged because they are directly pressed radially outward by the synthetic resin material forming the extension portion 22.

[0018] As can be understood by referring to Figures 2 to 4, a liner 26 is provided on the inner surface of the top wall 8 of the shell 4. This liner 26 is formed by supplying a suitable synthetic resin material, such as soft polyethylene, to the inner surface of the top wall 8 of the shell 4 and pressing the synthetic resin material into the required shape. The liner 26 is disc-shaped overall, and two annular protrusions, namely an inner annular protrusion 28 and an outer annular protrusion 30, are formed on the periphery of the liner 26.

[0019] Figure 5 shows the neck portion 100 of the container fitted with the container lid 2, along with the container lid 2, as indicated by a dashed line. The neck portion 100 of the container, which can be formed from glass or a suitable synthetic resin such as polyethylene terephthalate, is generally cylindrical in shape, and an annular locking projection 102 projecting radially outward is formed at the upper end of its outer circumferential surface. The outer circumferential surface of the locking projection 102 of the neck portion 100 has a diameter that gradually increases downward and is arc-shaped in a longitudinal cross-sectional view, and the lower surface of the locking projection 102 of the neck portion 100 has a diameter that gradually decreases downward and is arc-shaped in a longitudinal cross-sectional view, and an arc-shaped recess is formed on the outer circumferential surface of the neck portion 100 extending downward from the lower surface of the locking projection 102.

[0020] When attaching the container lid 2 to the neck portion 100 of the container, first, the container lid 2 is pressed downward against the neck portion 100 from the state shown in Figure 5. Figure 6 shows the state in which the container lid 2 has been pressed downward against the neck portion 100. In this state, the upper end of the extension portion 22 of the gripping piece 6 is positioned opposite the outer circumferential surface of the locking projection 102 of the neck portion 100, more specifically, its maximum outer diameter portion, and the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 of the pair of scores 18a and 18b are positioned opposite the outer circumferential surface of the locking projection 102 of the neck portion 100, more specifically, its maximum outer diameter portion, and the arc-shaped recess located below this maximum outer diameter portion. Next, while maintaining the state shown in Figure 6, the lower end of the skirt wall 10 is crimped radially inward on the underside of the locking projection 102 of the neck portion 100. As a result, as shown in Figure 7, the upper end of the extension 22 of the gripping piece 6 is sandwiched between the inner circumferential surface of the skirt wall 10 and the outer circumferential surface of the locking projection 102, specifically its maximum outer diameter portion, and thus the container lid 2 is attached to the neck portion 100.

[0021] In a container lid constructed according to the present invention, the residual material thickness of the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 of each of the pair of scores 18a and 18b is relatively thick, and therefore the lower parts 18a-1x and 18b-1x have sufficient strength, and the upper ends of the lower parts 18a-1x and 18b-1x are located near the upper end of the extension portion 22 of the gripping piece 6. Therefore, when the gripping piece 6 is injection molded or compression molded from a synthetic resin material using the connecting piece 12 of the shell 4 as a so-called core, even if the skirt wall 10 of the shell 4 or the connecting piece 12 is pressed radially outward by the molding pressure of the synthetic resin material forming the extension 22, and the first parts 18a-1 and 18b-1 of the pair of scores 18a and 18b are abused, the first parts 18a-1 and 18b-1 of the pair of scores 18a and 18b are prevented as much as possible from breaking when the lower end of the skirt wall 10 is crimped radially inward for attachment to the neck 100 of the container. When the lower end of the skirt wall 10 is crimped radially inward, the region where the extension portion 22 exists experiences a greater amount of strain than the region where the extension portion 22 does not exist, by the thickness of the extension portion 22. As a result, stress is applied to the vicinity of the circumferential direction of the extension portion 22, particularly to the first portions 18a-1 and 18b-1 of the pair of scores 18a and 18b. However, in a container lid constructed according to the present invention, as described above, the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 have sufficient strength. Therefore, even if the stress is applied to the lower parts 18a-1x and 18b-1x when the lower end of the skirt wall 10 is crimped radially inward, fracture of the lower parts 18a-1x and 18b-1x is prevented as much as possible. In view of such effects, as described above, it is sufficient that the upper ends of the lower parts 18a-1x and 18b-1x of the first portions 18a-1 and 18b-1 of the pair of scores 18a and 18b are located near the upper end of the extension portion 22 of the gripping piece 6. Therefore, the upper ends of the lower parts 18a-1x and 18b-1x are not necessarily limited to being at the same height as the upper end of the extension portion 22 of the gripping piece 6, but may be located somewhat above or below it.

[0022] When opening the neck 100 by detaching the container lid 2 from the neck 100 in order to consume the contents, the user places their fingers on the gripping portion 24 of the gripping piece 6 of the shell 4 and moves the gripping piece 6 radially outward or upward. This causes the pair of scores 18a and 18b formed on the shell 4 to break, releasing the locking of the lower end of the skirt wall 10 of the shell 4 to the annular locking projection 102 of the neck 100, and the container lid 2 is detached from the neck 100. At this time, in the container lid constructed according to the present invention, the residual material thickness of the remaining portions 18a-1y and 18b-1y of the first portions 18a-1 and 18b-1 of the pair of scores 18a and 18b, excluding the lower portions 18a-1x and 18b-1x, is relatively thin and therefore easily broken. Therefore, in a container lid constructed according to the present invention, each of the pair of scores 18a and 18b is difficult to break when attached to the neck of the container, but each of the pair of scores 18a and 18b is easily broken when opening the neck 100 of the container.

[0023] Although the container lid constructed according to the present invention has been described in detail above with reference to the attached drawings, the present invention is not limited to the embodiments described above, and appropriate modifications and changes are possible without departing from the present invention.

[0024] 2: Container lid 4: Shell 6: Gripping piece 8: Top wall 10: Skirt wall 12: Connecting piece 18a, 18b: Pair of scores 18a-1, 18b-1: First part of the score 18a-1x and 18b-1x: Lower part of the first part of the score 18a-1y and 18b-1y: Remaining part of the first part of the score 20: Connecting part 22: Extension part 24: Gripping part 100: Neck part 102: Locking projection

Claims

1. A container lid for a container having a neck with an annular locking projection projecting radially outward at the upper end of the outer circumferential surface, the container lid having a circular top wall, a cylindrical skirt wall hanging down from the periphery of the top wall, and a connecting piece extending from the lower end of the skirt wall in a predetermined region in the circumferential direction, the skirt wall and the top wall having a pair of scores formed on both sides of the predetermined region, extending upward from the lower end of the skirt wall and then extending along the top wall, each of the pair of scores comprising a metal sheet shell having a first portion extending upward from the lower end of the skirt wall, and a synthetic resin gripping piece connected to the connecting piece, the container lid including a connecting portion that at least partially surrounds the connecting piece, an extension portion extending upward from the upper inner surface of the connecting portion along the inner circumferential surface of the skirt wall, and a gripping portion extending downward from the connecting portion, A container lid characterized in that the material residue thickness at the bottom of each of the pair of scores is relatively thick, and the upper end of the bottom is located near the upper end of the extension of the gripping piece.

2. The container lid according to claim 1, wherein, when fitted over the neck and pressed downward against the neck, the upper end of the extension of the gripping piece is positioned opposite the outer circumferential surface of the locking projection of the neck, and the lower part of the first portion of each of the pair of scores is positioned opposite the outer circumferential surface of the locking projection of the neck, and in this state, the lower end of the skirt wall is crimped radially inward below the locking projection of the neck, thereby the upper end of the extension of the gripping piece is sandwiched between the inner circumferential surface of the skirt wall and the outer circumferential surface of the locking projection and attached to the neck.

3. The container lid according to claim 1, wherein each of the pair of scores is formed on the inner surface of the shell.

4. The container lid according to claim 1, wherein the extension of the gripping piece has a trapezoidal shape in which the circumferential width decreases toward the upward.

5. The container lid according to claim 1, wherein the gripping piece is molded from a hard synthetic resin having a Shore D hardness of 55 to 73.

6. The container lid according to claim 1, wherein the shell is formed from an aluminum-based alloy sheet.

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