Easily openable container lid

Abstract

An easily openable container lid includes a shell and liner. The shell includes a flat circular top wall, a skirt wall having an arcuate part extending arcuately radially outward and downward from the peripheral edge of the top wall in a longitudinal cross sectional view and a linear part extending vertically downward following the arcuate part, and a grip piece extending from the lower end of the skirt wall. The top wall, the skirt wall and at least a base part of the grip piece are integrally formed of a metal sheet, and a pair of scores each composed of first and second portions are formed on the shell. The first portions extend on the skirt wall upward from both sides of the grip piece, and the second portions extend arcuately between the upper end part of the skirt part and the peripheral edge part of the top wall.

Claims

1. An easily openable container lid for a container that has a cylindrical mouth-neck section having an annular locking ridge formed at an upper end part of an outer peripheral surface, the cylindrical mouth-neck section is to be sealed to have a positive internal pressure after a gas-containing liquid is accommodated within the container, the container lid comprising a shell and a liner, wherein the shell comprises a flat circular top panel wall, a skirt wall having an arcuate part extending arcuately radially outward and downward from a peripheral edge of the flat circular top panel wall in a longitudinal cross sectional view and a linear part extending vertically downward to follow the arcuate part, and a grip piece extending from a lower end of the skirt wall, the flat circular top panel wall, the skirt wall and at least a base part of the grip piece are integrally formed of a metal sheet, and a pair of scores each including a first portion and a second portion are formed, where the first portions extend upward on the skirt wall from both sides of the grip piece, and the second portions extend arcuately between an upper end part of the skirt wall and a peripheral edge part of the flat circular top panel wall, the liner, which is disc-shaped and made of a synthetic resin, is disposed on an inner surface of the flat circular top panel wall of the shell, the container lid is attached to the cylindrical mouth-neck section by swaging a lower part of the linear part of the skirt wall radially inward below the annular locking ridge of the cylindrical mouth-neck section, the respective first portions of the pair of scores extend straight and vertically from the lower end of the skirt wall to a site above an upper end of the lower part of the linear part, and t1>t2>t3, wherein t1 denotes a material residual thickness of the pair of scores at a site of the first portions, ranging from the lower end of the skirt wall of the first portions, above the upper end of the lower part of the linear part of the skirt wall and to an intermediate part of the linear part other than the lower part, t2 denotes a material residual thickness of the pair of scores at a remainder of the first portions, and t3 denotes a material residual thickness of the pair of scores at the second portions and at third portions.

2. The easily openable container lid according to claim 1, wherein t1 is 170 to 190 m, t2 is 155 to 175 m, and t3 is 110 to 130 m.

3. The easily openable container lid according to claim 2, wherein the respective first portions of the pair of scores extend straight to the upper end of the linear part of the skirt wall, and extend upward and arcuately to a direction to be circumferentially spaced from each other at the arcuate part of the skirt wall.

4. The easily openable container lid according to claim 3, wherein the liner is non-adhesive or weakly adhesive to the shell in a pair of arcuate regions extending along the pair of scores and covering the pair of scores while the liner is adhered to the shell in regions other than the pair of arcuate regions.

5. The easily openable container lid according to claim 4, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

6. The easily openable container lid according to claim 3, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

7. The easily openable container lid according to claim 2, wherein the liner is non-adhesive or weakly adhesive to the shell in a pair of arcuate regions extending along the pair of scores and covering the pair of scores while the liner is adhered to the shell in regions other than the pair of arcuate regions.

8. The easily openable container lid according to claim 7, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

9. The easily openable container lid according to claim 2, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

10. The easily openable container lid according to claim 1, wherein the respective first portions of the pair of scores extend straight to the upper end of the linear part of the skirt wall, and extend upward and arcuately to a direction to be circumferentially spaced from each other at the arcuate part of the skirt wall.

11. The easily openable container lid according to claim 10, wherein the liner is non-adhesive or weakly adhesive to the shell in a pair of arcuate regions extending along the pair of scores and covering the pair of scores while the liner is adhered to the shell in regions other than the pair of arcuate regions.

12. The easily openable container lid according to claim 11, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

13. The easily openable container lid according to claim 10, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

14. The easily openable container lid according to claim 1, wherein the liner is non-adhesive or weakly adhesive to the shell in a pair of arcuate regions extending along the pair of scores and covering the pair of scores while the liner is adhered to the shell in regions other than the pair of arcuate regions.

15. The easily openable container lid according to claim 14, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

16. The easily openable container lid according to claim 1, wherein the liner has a thin-walled centration section and a thick-walled peripheral edge section, the thick-walled peripheral edge section has a lower surface on which an internal annular sealant and an external annular sealant both extending concentrically downward are formed, and a lower end of the external annular sealant is positioned above an upper end of the linear part of the skirt wall.

17. The easily openable container lid according to claim 16, wherein the lower end of the external annular sealant is positioned as high as a vertically intermediate site of the arcuate part of the skirt wall.

18. The easily openable container lid according to claim 17, wherein a lower end of the internal annular sealant is positioned below the lower end of the external annular sealant and above the upper end of the linear part of the skirt wall.

19. The easily openable container lid according to claim 16, wherein a lower end of the internal annular sealant is positioned below the lower end of the external annular sealant and above the upper end of the linear part of the skirt wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view showing a suitable embodiment of container lid configured according to the present invention.

(2) FIG. 2 is a cross sectional view partly showing the container lid of FIG. 1.

(3) FIG. 3 is a developed view showing an example of a pair of scores in the container lid of FIG. 1.

(4) FIG. 4 is a developed view for showing the relation between a liner and a top panel wall of a shell in the container lid of FIG. 1.

(5) FIG. 5 is a partly cross sectional side view showing the container lid of FIG. 1, which is attached to the mouth-neck section of a container.

MODE FOR CARRYING OUT THE INVENTION

(6) A preferred embodiment of a container lid configured in accordance with the present invention will now be described in further detail with reference to the attached drawings.

(7) The following explanation is made referring to FIGS. 1 and 2. A container lid indicated with a numeral 2 consists of a shell 4 and a liner 6 (see FIG. 2).

(8) The shell 4 comprises a circular top panel wall 8, a cylindrical skirt wall 10 hanging down from the peripheral edge of the top panel wall 8, and a grip piece 12 extending from the lower end of the skirt wall 10. As clearly understandable by referring to FIG. 2, the skirt wall 10 has an arcuate part 10a that extends arcuately radially outward and downward from the peripheral edge of the top panel wall 8 and a linear part 10b that extends vertically downward to follow the arcuate part 10a in the longitudinal cross sectional view of FIG. 2. As will be explained later more in detail, in attaching the container lid 2 to the mouth-neck section 32 (see FIG. 5) of the container, a lower part 10b-1 of the linear part 10b of the skirt wall 10 is deformed radially inward to be swaged to the annular locking ridge 34 (see FIG. 5) of the mouth-neck section 32. The base part 14 of the grip piece 12 (see also FIG. 3) is formed integrally with the top panel wall 8 and the skirt wall 10 through suitable machining works like punching and drawing to suitable metal sheets such as an aluminum-based alloy sheet, a chromic acid treated steel sheet or a tin sheet. Notches 16a and 16b are formed at the lower end part of the skirt wall 10, specifically at the both sides of the base part 14 of the grip piece 12. The grip piece 12 consists of the base part 14 and a ring part 18 linked thereto. The ring part 18 of the grip piece 12 is formed by injection-shaping or compression-shaping any suitable synthetic resin material like polypropylene or polyethylene, using as a core the base part 14 of the grip piece 12, so that the ring portion 18 can be linked to the base portion 14 at the same time of the formation. If necessary, it is also possible to integrally form the entire grip piece 12, the top panel wall 8 and the skirt wall 10, from a metal sheet.

(9) A pair of scores 20a and 20b are formed on the shell 4, or more specifically, on the areas integrally formed from the metal sheet. The pair of scores 20a and 20b are favorably formed by working the metal sheet from its back surface with a tool for decreasing the thickness of the metal sheet. The scores 20a and 20b comprise first portions 20a-1 and 20b-1 and further, second portions 20a-2 and 20b-2. The first portions 20a-1 and 20b-1 extend upward on the skirt wall 10 from the lower end of the skirt wall 10, more specifically, from the notches 16a and 16b formed on the both sides of the grip piece 12. The second portions 20a-2 and 20b-2 following respectively the first portions 20a-1 and 20b-1 extend arcuately between the upper end part of the skirt wall 10 and the peripheral edge part of the top panel wall 8. In the illustrated embodiment, the second portions 20a-2 and 20b-2 extend on the peripheral edge part of the top panel wall 8. In the illustrated embodiment, third portions 20a-3 and 20b-3 are additionally formed (see also FIG. 3). The third portions 20a-3 and 20b-3 that follow the second portions 20a-2 and 20b-2 extend to the skirt wall 10.

(10) FIG. 3 shows a metal sheet to make the top panel wall 8, the skirt wall 10 and the base part 14 of the grip piece 12 of the shell 4. The metal sheet in FIG. 3 has been punched to make the respective parts but not yet drawn. In other words, FIG. 3 shows one surface of the metal sheet that defines the inner surfaces of the top panel wall 8 and the skirt wall 10 in the state where the base part 14 of the grip piece 12 with the top panel wall 8 and the skirt wall 10 of the shell 4 is expanded in a plane. The pair of scores 20a and 20b can be formed suitably by forming grooves on the plane for defining the inner surfaces of the top panel wall 8 and the skirt wall 10 (the surfaces shown in FIG. 3) thereby decreasing the material thickness at the same time of punching the metal sheet to a desired shape, or before drawing the metal sheet before/after the punching. Alternatively, it is possible to form the scores 20a and 20b by forming grooves on the plane to define the outer surfaces of the top panel wall 8 and the skirt wall 10, thereby decreasing the material thickness. However, this can cause rupture at the pair of scores 20a and 20b, in particular at sites where the arcuate part 10a of the skirt wall 10 extends during the drawing of the metal sheet. In the pair of scores 20a and 20b, t1 denotes a material residual thickness at a site of the first portions 20a-1 and 20b-1, ranging from the lower end of the skirt wall 10 of the first portions 20a-1 and 20b-1, above the upper end of the lower part 10b-1 of the linear part 10b of the skirt wall 10, and to the intermediate part of the linear part other than the lower part 10b-1; t2 denotes a material residual thickness at the rest of the first portions 20a-1 and 20b-1 (i.e., the site other than the site ranging from the lower end of the skirt wall 10 to the intermediate part of the linear part other than the lower part 10b-1 of the linear part 10b of the skirt wall 10 through the upper end of the lower part 10b-1, and also a site positioned at the arcuate part 10a of the skirt wall 10); and t3 denotes a material residual thickness at the second portions 20a-2 and 20b-2, and at the third portions 20a-3 and 20b-3. Preferably, the value of t1 is comparatively large, t2 is a median, and t3 is comparatively small. For instance, in a case where the metal sheet is of an aluminum-based alloy having a thickness of 0.24 mm, suitably t1 is in a range of about 170 to about 190 m, t2 is in a range of about 155 to about 175 m, and t3 is in a range of about 110 to about 130 m.

(11) The following explanation is made referring to FIG. 3 together with FIGS. 1 and 2. It is important that the first portions 20a-1 and 20b-1 in the pair of scores 20a and 20b extend straight and preferably vertically (namely, parallel to the central axis of the container 2) from the lower end of the skirt wall 10 to the site above the upper end of the lower part 10b-1 of the linear part 10b (in FIG. 3, the upper end is indicated with a long dashed double-short dashed line A). In the illustrated embodiment, the first portions 20a-1 and 20b-1 of the pair of scores 20a and 20b extend straight and vertically from the lower end of the skirt wall 10 to the upper end of the linear part 10b (in FIG. 3, the upper end is indicated with a long dashed double-short dashed line B). In FIG. 3, this area is indicated with signs 20a-1-1 and 20b-1-1. On the arcuate part 10a of the skirt wall 10, the first portions 20a-1 and 20b-1 of the pair of scores 20a and 20b extend arcuately and upward circumferentially to the both sides (which is the area indicated with reference signs 20a-1-2 and 20b-1-2 in FIG. 3).

(12) The following explanation is made referring to FIG. 2. The liner 6 in this embodiment is formed by applying a suitable synthetic resin material like a soft polyethylene onto the inner surface of the top panel wall 8 of the shell 4, and by embossing the synthetic resin material to have a desired shape. The liner 6 has a disk shape as a whole, and it has a comparatively thin-walled centration section 22 and a comparatively thick-walled peripheral edge section 24. At the thick-walled peripheral edge section 24, an internal annular sealant 26 and an external annular sealant 28 both concentrically hanging down are formed. The experiments by the present inventors shows that preferably the lower end of the external annular sealant 28 is positioned above the upper end of the linear part 10b of the skirt wall 10 so that the inner pressure of the container can be released at a relatively early stage in detaching the container lid 2 from the mouth-neck section 30 (see FIG. 5) of the container, and more preferably, it is as high as the vertically intermediate site of the arcuate part 10a of the skirt wall 10. It is also possible that the lower end of the internal annular sealant 26 is positioned below the lower end of the external annular sealant 28 and above the upper end of the linear part 10b of the skirt wall 10.

(13) FIG. 4 schematically shows the relation between the inner surface of the top panel wall 8 and the liner 6. In the illustrated embodiment, an adhesive paint for adhering to the liner 6 is applied on the entire inner surface that defines the inner surface of the top panel wall 8 (one of the surfaces of the metal sheet for forming the base part 14 of the grip piece 12 integrally with the top panel wall 8 and the skirt wall 10 of the shell 4). In FIG. 4, areas stippled at a high-density indicate the regions applied additionally with a non-adhesive or weakly adhesive paint for adhering to the liner 6. It will be understandable by referring to FIG. 2 together with FIG. 4 that the non-adhesive or weakly adhesive paint is applied to a pair of arcuate regions 30a and 30b. These arcuate regions 30a and 30b are present along the second portions 20a-2 and 20b-2 of the pair of scores 20a and 20b, and cover the second portions 20a-2 and 20b-2 of the pair of scores 20a and 20b. Therefore, in the pair of arcuate regions 30a and 30b, the liner 6 is non-adhesive or weakly adhesive to the inner surface of the top panel wall 8 of the shell 4, while the liner 6 is adhered to the remaining region of the inner surface of the top panel wall 8 of the shell 4.

(14) FIG. 5 illustrates a state where the container lid 2 is attached to the mouth-neck section 32 of the container and the mouth-neck section 32 is sealed. The container can be formed of glass, any suitable synthetic resins like polyethylene terephthalate or a sheet of a metal like aluminum-based alloy. At the outer peripheral end part of the mouth-neck section 32, an annular locking ridge 34 is formed. For attaching the container lid 2 to the mouth-neck section 32 thereby sealing the mouth-neck section 32, the container lid 2 is fitted to the mouth-neck section 32 and pressed downward to bring the internal annular ridge 26 and the external annular ridge 28 of the liner 6 into close contact with the upper end part of the mouth-neck section 32. Next, the lower part 10b-1 of the linear part 10b of the skirt wall 10 is swaged (deformed) radially inward to be locked by the lower surface 34a of the annular locking ridge 34 of the mouth-neck section 32. In this manner, the container lid 2 is attached to the mouth-neck section 32 of the container to seal the mouth-neck section 32.

(15) In consuming the content accommodated within the container, the container is opened by detaching the container lid 2 from the mouth-neck section 32. In that case, the consumer hooks his finger on the ring part 18 of the shell 4 of the container lid 2 and pulls the part radially outward, and then upward. In this manner, the first portions 20a-1 and 20b-1 of the pair of scores 20a and 20b are ruptured to the vicinity of the upper end of the lower part 10b-1 of the linear part 10b of the skirt wall 10. At the same time, the ruptured site between the first portions 20a-1 and 20b-1 of the pair of scores 20a and 20b at the lower part 10b-1 of the linear part 10b of the skirt wall 10 is displaced radially outward and upward to be spaced from the annular locking ridge 34, whereby the inner pressure of the container is released suitably. At that time, the site other than the specific site between the first portions 20a-1 and 20b-1 of the ruptured pair of scores 20a and 20b, at the lower part 10b-1 of the linear part 10b of the skirt wall 10, is still locked by the lower surface 34a of the annular locking ridge 34 of the mouth-neck section 32. As a result, it is possible to avoid the container lid 2 from vigorously flying/dropping off. Furthermore, since the first portions 20a-1 and 20b-1 of the pair of scores 20a and 20b disposed on the lower part 10b-1 of the linear part 10b of the skirt wall 10 extend straight, they can be ruptured without applying excessive force. In contrast, in a conventional container lid, a pair of scores extend arcuately upward and circumferentially to the both sides at the lower parts of the first portions of the skirt wall as indicated with a long dashed double-short dashed line X in FIG. 3. When the score is ruptured at the lower part of the first portion of the skirt wall, the lower part of the linear part of the skirt wall is displaced radially outward and upward at the site that is circumferentially longer in comparison with the counterpart of the present invention, and the lower part is separated from the mouth-neck section. As a result, the locking force of the container lid 2 with respect to the mouth-neck section 32 will be decreased excessively, and this may cause a risk that the container lid fly/drop off vigorously. Further, in the container lid, the lower part of the first portion of the skirt wall extends arcuately toward the circumferential both side and upward. This configuration requires application of force for rupture upward and simultaneously toward the circumferentially both sides, and thus, rupture requires a relatively large force.

(16) The ring part 18 is further displaced upward or to the diametrically opposite direction so as to further rupture the area other than the first portions 10a-1 and 10b-1 of the pair of scores 10a and 10b, and rupture the second portions 10a-2 and 10b-2. As a result, the lower part 10b-1 of the linear part 10b of the skirt wall 10 is spaced from the annular locking ridge 34 of the mouth-neck section 32 for a certain length in the circumferential direction. As a result, the lower part 10b-1 is detached from the mouth-neck section 32 of the container lid 2, and thus, the mouth-neck section 32 is unsealed.

Example

(17) An aluminum-based alloy sheet having a thickness of 0.24 mm was punched out to have a shape as shown in FIG. 3, and subsequently worked as required, for instance, drawn to form a shell having a top panel wall, skirt wall, and a base part fora grip piece as shown in FIGS. 1 and 2. Next, a polypropylene ring was formed by compression on the base part of the grip piece, and a soft polyethylene liner was formed by pressing onto the inner surface of the top panel wall, whereby a container lid as shown in FIGS. 1 and 2 was produced. The outer diameter of the shell was 27.00 mm, the overall height of the skirt wall (excluding the grip piece) was 7.00 mm, the vertical length of the linear part of the skirt wall was 4.26 mm, and the vertical length of the lower part of the linear part of the skirt wall was 1.75 mm. The lower end of the external annular sealant of the liner was positioned 1.20 mm above the upper end of the linear part of the skirt wall, and the lower end of the internal annular sealant of the liner was positioned 0.90 mm above the upper end of the linear part of the skirt wall.

(18) In the pair of scores, t1 denotes a material residual thickness at a site, specifically the site ranging from the lower end of the skirt wall of the first portions, above the upper end of the lower part of the skirt wall, and to the intermediate of the linear part other than the lower part; t2 denotes a material residual thickness at the rest of the first portions; and t3 denotes a material residual thickness at the second portions and the third portions. The thickness t1 was 180 m, the thickness t2 was 165 m, and the thickness t3 was 120 m. The radius of curvature of the pair of scores at the portion located at the arcuate part of the skirt wall was 5.00 mm.

(19) A glass container (nominal capacity: 120 ml) having a mouth-neck section as shown in FIG. 5 accommodated 120 ml of water containing 3.4 volumes of carbonic acid. At the mouth-neck section of the container, a container lid was attached as shown in FIG. 5, and the mouth-neck section was sealed. The container with the sealed mouth-neck section was left stand for three days in an environment of 50 C., and then, the container lid was detached from the mouth-neck section to unseal the mouth-neck section. As a result of conducting the same procedures for 150 containers, there was no container lid flying/dropping off at the time of detaching from the mouth-neck section.

Comparative Example

(20) For comparison, the same experiment as that for the aforementioned Example was conducted for 150 containers, except that the shape of the first portions of the pair of scores formed on the shell was as indicated with the long dashed double-short dashed line X in FIGS. 1 and 2, the radius of curvature was 8.00 mm, the lower end of the external annular sealant of the liner was positioned 1.20 mm below the upper end of the linear part of the skirt wall, and the lower end of the internal annular sealant of the liner was positioned 0.90 mm above the upper end of the linear part of the skirt wall. As a result, the container lids of fifteen containers were flew/dropped off vigorously at the time the lids were detached from the mouth-neck sections.

EXPLANATIONS OF LETTERS OR NUMERALS

(21) 2: Container lid 4: Shell 6: Liner 8: Top panel wall 10: Skirt wall 10a: Arcuate part of skirt wall 10b: Linear part of skirt wall 10b-1: Lower part of linear part 12: Grip piece 14: Base part of grip piece 16a: Notch 16b: Notch 18: Ring part 20a: Score 20b: Score 20a-1: Score's first portion 20b-1: Score's first portion 20a-2: Score's second portion 20b-2: Score's second portion 20a-3: Score's third portion 20b-3: Score's third portion 22: Thin-walled centration section of liner 24: Thick-walled peripheral edge section of liner 26: Internal annular sealant 28: External annular sealant 30a: Arcuate region to be applied with non-adhesive or weakly adhesive paint 30b: Arcuate region to be applied with non-adhesive or weakly adhesive paint 32: Container's mouth-neck section 34: Annular locking part