JP2006160296A - Container lid with inner pressure releasing characteristic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container lid (2) having sufficient falling impact resistant characteristics even though the lid is capable of sufficiently and reliably releasing the internal pressure when the internal pressure of the container is excessively increased. <P>SOLUTION: A bridging part in an internal pressure releasing line (36) consists of high-strength bridging parts (34a and 34a') in which the width in the peripheral direction is relatively large, and one or a plurality of low-strength bridging parts (34b) which is arranged between adjacent high-strength bridging parts with the circumferential width being relatively small. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a container lid having an internal pressure release characteristic, that is, a characteristic of automatically opening a container internal pressure when the container internal pressure rises excessively.

  Patent Document 1 below discloses a container lid having an internal pressure release characteristic. Such a container lid includes a thin metal sheet shell having a circular top wall and a cylindrical skirt wall depending from the peripheral edge of the top wall, and a synthetic resin liner disposed in the shell. An internal pressure release line extending in the circumferential direction is disposed at the upper end of the skirt wall of the shell. The internal pressure release line is composed of a high-strength region extending over an angle range of at most 10 degrees and a low-strength region extending over the remaining angle range. There are no slits in the high-strength region, and the high-strength region is defined by a continuous high-strength bridge. The low-strength region is composed of a large number of low-strength bridge portions arranged at predetermined intervals in the circumferential direction and a large number of slits existing between the low-strength bridge portions. The circumferential width of the low-strength bridge is set to be considerably smaller than the circumferential width of the high-strength bridge.

When the container lid is attached to the mouth and neck of the container and the contents of the container are excessively heated with the mouth and neck sealed, or once the container lid is removed from the mouth and neck, If the contents rot and ferment after the container lid is attached and the mouth and neck are sealed, the internal pressure of the container may increase excessively. However, in the container lid as described above, if the internal pressure of the container rises excessively, the excessive strength acting on the container lid breaks the low-strength bridge in the internal pressure release line and exists in the high-strength region. The top wall of the shell is pivoted upward with the high-strength bridge as the pivot center, and the liner is also pivoted upward, thereby releasing the excessive internal pressure in the container. Thus, it is possible to avoid the danger that the container ruptures or the entire container lid detaches from the mouth and neck of the container and is allowed to fly.
No. 7-25318

  Thus, in the conventional container lid described above, when the internal pressure of the container is excessively increased, the internal pressure can be released. If the container is dropped from a relatively low height with the container sealed, the low-strength bridge in the internal pressure release line of the shell is broken due to the drop impact, and the container is damaged. There is a lot of danger of it.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to improve the conventional container lid described above, and to release the internal pressure sufficiently reliably when the internal pressure of the container rises excessively. Despite being able to do so, it is necessary to have sufficient drop impact resistance.

  As a result of intensive studies and experiments, the present inventors have determined that the bridge portion in the internal pressure release line is disposed between the high-strength bridge portion having a relatively large circumferential width and the adjacent high-strength bridge portion, respectively. It has been found that the main technical problem can be achieved by comprising one or a plurality of low-strength bridges having a relatively small width.

That is, according to the present invention, as a container lid that achieves the main technical problem, a thin metal plate shell having a circular top wall and a cylindrical skirt wall depending from the peripheral edge of the top wall, and disposed in the shell An inner pressure release line extending in the circumferential direction is provided at the upper end of the skirt wall of the shell, and the inner pressure release line is spaced apart in the circumferential direction. In the container lid composed of a number of slits extending in the circumferential direction and a number of bridging portions existing between the slits,
The bridging portion in the internal pressure release line has one or a plurality of relatively small circumferential widths disposed between a high strength bridging portion having a relatively large circumferential width and an adjacent high strength bridging portion. A container lid characterized by comprising a low-strength bridge portion is provided.

  One low-strength bridging portion can be disposed between adjacent high-strength bridging portions. All the circumferential lengths of the slits may be substantially the same. The circumferential width of the low-strength bridging portion is preferably 0.5 to 0.8 mm. Preferably, the high-strength bridge includes one ultra-high-strength bridge having a circumferential width larger than that of a normal high-strength bridge, and the circumferential width of the normal high-strength bridge is 2.0. To 5.0 mm, and the circumferential width of the ultrahigh-strength bridging portion is 5.0 to 10.0 mm.

  In the container lid of the present invention, when the internal pressure of the container rises excessively, the internal pressure can be released with certainty, but the drop impact resistance is greatly improved compared to the conventional container lid. It is done.

  Hereinafter, a preferred embodiment of a container lid configured according to the present invention will be described in more detail with reference to the accompanying drawings.

  FIG. 1 illustrates a preferred embodiment of a container lid constructed in accordance with the present invention. The container lid indicated by the whole number 2 is composed of a thin metal shell 4 and a synthetic resin liner 6.

  The shell 4 which is advantageously formed from an aluminum-based alloy thin plate having a thickness of about 0.22 to 0.26 mm includes a circular top wall 8 and a substantially cylindrical skirt wall depending from the periphery of the top wall 8. 10 and. A rupture line 12 extending in the circumferential direction is formed at a lower portion of the skirt wall 10, and the skirt wall 10 is formed into a main portion 14 above the break line 12 and a tamper evidence skirt portion 16 below the break line 12. It is partitioned. More specifically, an annular bulging portion 18 bulging outward in the radial direction is formed at the lower portion of the skirt wall 10, and the annular bulging portion 18 is spaced at an appropriate interval in the circumferential direction. A plurality of slits 20 extending in the circumferential direction are formed, and the breaking line 12 is defined by a plurality of slits 20 and a plurality of bridging portions 22 positioned between the slits 20. The tamper evidence skirt portion 16 is connected to the main portion 14 via the bridging portion 22.

An annular groove 24 is formed at a substantially central portion in the axial direction of the main portion 14 of the skirt wall 10.
Above the annular groove 24, an uneven portion is formed in which concave portions 28 and convex portions 30 are alternately present in the circumferential direction. The upper and lower edges of the concavo-convex shape portion have a large number, preferably 20 to 30 slits 32 extending in the circumferential direction at intervals in the circumferential direction, and a large number, preferably 20 to 30 present between the slits 32. An internal pressure release line 36 composed of the bridging portions 34a, 34a 'and 34b is provided.

  Continuing with reference to FIG. 1 and FIG. 2, in the illustrated embodiment, the circumferential lengths of the multiple slits 32 in the internal pressure release line 36 are all substantially the same. On the other hand, many of the bridging portions in the internal pressure release line 36 have a relatively small circumferential width disposed between the high-strength bridging portion 34a having a relatively large circumferential width and the adjacent high-strength bridging portion 34a. It is important that it is composed of one or a plurality of, preferably one, two or three, low-strength bridge portions 34b. In the illustrated embodiment, one low-strength bridging portion 34b is disposed between adjacent high-strength bridging portions 34a. Furthermore, in the illustrated embodiment, one of the plurality of high-strength bridge portions 34a is an ultra-high-strength bridge portion 34a 'for ensuring safety, and the other is a normal high-strength bridge portion. 34a. The circumferential width wa of the normal high-strength bridging portion 34a is 2.0 to 5.0 mm, and the circumferential width wa ′ of the ultra-high-strength bridging portion 34a ′ is 5.0 to 10.0 mm. Is preferred. On the other hand, the circumferential width wb of the low-strength bridging portion 34b is preferably 0.5 to 0.8 mm. The circumferential length ws of the slit 32 may be about 1.0 to 5.0 mm.

  Referring back to FIG. 1, the liner 6 that can be formed from an appropriate synthetic resin such as soft polyethylene is disposed on the inner surface of the top wall 8 of the lid body 4. Such a liner 6 can be conveniently formed by supplying a soft and molten synthetic resin material to the inner surface of the top wall 8 and embossing the synthetic resin material into a required shape. The liner 6 in the illustrated embodiment includes a relatively thin circular central portion 40 and a relatively thick annular peripheral portion 42. Two annular ridges projecting downward, that is, an outer annular ridge 44 and an inner annular ridge 46 are formed on the annular peripheral edge 42. The outer peripheral surface of the outer annular ridge 44 is substantially cylindrical, the lower surface is substantially horizontal, and the inner peripheral surface is substantially frustoconical. The upper half of the outer peripheral surface of the inner annular ridge 46 has a substantially inverted conical shape, and the lower half has a substantially cylindrical shape. The lower end of the outer peripheral surface is connected to the substantially horizontal lower surface via the arc-shaped portion, and the inner peripheral surface. Is substantially cylindrical. The radial thickness of the outer annular ridge 44 is relatively large, and the radial thickness of the inner annular ridge 46 is relatively small. On the other hand, the protruding length of the outer annular ridge 44 downward is relatively small, and the protruding length of the inner annular ridge 46 downward is relatively large. The lower surface of the portion between the outer annular ridge 44 and the inner annular ridge 46 in the annular peripheral edge 42 is substantially horizontal. The other region of the liner 6 is bonded to the inner surface of the top wall 8 of the shell 4, but the radially outer region of the annular peripheral edge of the liner 6, for example, the region indicated by x in FIG. From the viewpoint of impact resistance, it is preferable that the surface wall 8 is not adhered to the inner surface.

  1 and 3 also show the mouth and neck 48 of the container to which the container lid 2 is applied. The illustrated container is formed of an aluminum-based alloy thin plate and has a substantially cylindrical mouth-neck portion 48. The upper end portion of the mouth / neck portion 48 has a truncated cone shape that is inclined inward in the radial direction upward, and an outer winding curl 50 is formed at the upper end. A male thread 52 is formed at an axially intermediate portion of the mouth-and-neck section 48, and an annular locking jaw 54 bulging outward in the radial direction is formed below the male thread 52. The container lid 2 constructed in accordance with the present invention is not limited to an aluminum-based alloy sheet container having the mouth-and-neck portion 48 of the illustrated form, but various forms formed from a metal sheet, glass, or an appropriate synthetic resin. Needless to say, the present invention can be applied to a container having a mouth and neck.

  The description will be continued with reference to FIG. 1 and FIG. 3. When the container lid 2 is attached to the mouth / neck portion 48 and the mouth / neck portion 48 is sealed, the container lid 2 is fitted on the mouth / neck portion 48. Thus, as shown in FIG. 1, the inner peripheral surface of the outer annular ridge 44 of the liner 6 is brought into contact with the outer surface of the top surface of the outer curl 50 of the mouth neck 48. Next, as shown in FIG. 3, the container lid 2 is pressed downward so that the inner peripheral surface of the liner 6, particularly the outer annular ridge 44, is the top surface or upper end of the outer peripheral curl 50 of the mouth-and-neck portion 48. Closely close. Then, the boundary region between the top wall 8 of the shell 4 and the skirt wall 10 is deformed downward and radially inward to form an annular recess 56, and the annular groove 24 in the main portion 14 of the skirt wall 10 is formed in the region below. The female thread 58 is formed so as to correspond to the male thread 52 of the mouth-and-neck part 48, and the lower part of the tamper-evidence skirt part 16 of the shell 4 is displaced inward in the radial direction. Lock to the stop jaw 54. When there is a possibility that the contents overflowing when the contents are filled in the container are attached to the outer peripheral surface of the mouth-and-neck part 48, a cleaning liquid that is clean water can be sprayed onto the container lid 4. . Thus, the sprayed cleaning liquid enters between the shell 4 and the mouth and neck portion 48 through the slit 32 in the internal pressure release line 36 formed on the skirt wall 10 of the shell 4, and the outer peripheral surface of the mouth and neck portion 48. Wash away the contents adhering to.

  When opening the mouth / neck portion 48 of the container sealed by the container lid 2, the container lid 2 is rotated in the opening direction, that is, counterclockwise as viewed from above in FIG. As a result, the female thread 58 formed on the skirt wall 10 moves along the male thread 52 formed on the mouth-and-neck portion 48, and therefore does not rise with rotation. However, since the tamper evidence skirt 16 is locked to the annular locking jaw 54, the tamper evidence skirt 16 is prevented from rising, so that considerable stress is generated at the breaking line 12, and more specifically at the bridging portion 22 thereof. The portion 22 is broken and the tamper evidence skirt 16 is separated from the main portion 14 of the skirt wall 10. After that, the container lid 2 is lifted with rotation except for the tamper-evidence skirt portion 16 and is detached from the mouth-and-neck portion 48, thus opening the mouth-and-neck portion 48. When it is desired to temporarily re-seal the mouth-and-neck portion 48 once opened, the container lid 2 detached from the mouth-and-neck portion 48 is fitted again on the mouth-and-neck portion 48 and closed in the closed direction, that is, in FIG. It is only necessary to rotate clockwise when viewed from above and screw the female thread 58 of the container lid 2 to the male thread 52 of the mouth-and-neck portion 48. When the female thread 58 is fully screwed into the male thread 52, the inner circumferential surface of the liner 6, particularly the outer annular projection 44, is again the top surface of the outer curl 50 or the upper end of the outer circumferential surface of the neck portion 48. And the mouth-neck 48 is sealed.

  Thus, in a state where the container lid 2 is attached to the mouth / neck portion 48 of the container and the mouth / neck portion 48 is sealed, the container lid 2 is once detached from the mouth / neck portion 48, for example, due to excessive heating of the container. After that, when the container lid 2 is attached to the mouth / neck portion 48 again and the mouth / neck portion 48 is sealed, and the contents decay and ferment, the internal pressure of the container is excessively increased. Is broken. On the other hand, the high-strength bridge portion 34a and the ultra-high-strength bridge portion 34a ′ are maintained without being broken. Therefore, as shown by a two-dot chain line in FIG. 3, between the adjacent high-strength bridging portion 34a and ultrahigh-strength bridging portion 34a ′, the liner 6 disposed on the top wall of the shell 4 and the inner surface thereof is provided. Displaced locally upwards, thus the liner 6 is locally separated from the container neck 48 and the excessive internal pressure is released. Therefore, the container is ruptured by the excessively increased internal pressure or the container lid 2 is prevented from flying from the mouth / neck portion 48 with sufficient reliability.

  On the other hand, for example, even if a container in which the mouth / neck 48 is sealed by the container lid 2 is dropped in an inverted state and a considerable impact is applied to the container lid 2, high strength is applied to both sides of the low-strength bridging portion 34b. Due to the presence of the bridging portion 34a or the ultra-high strength bridging portion 34a ′, it is possible to reliably prevent the sealing of the mouth and neck portion 48 from being damaged.

The front view which shows a suitable embodiment of the container lid comprised according to this invention in part in a cross section. The expanded view which shows the skirt wall of the shell in the container lid of FIG. The front view which shows the state which mounted | wore the mouth neck part of the container with the container lid shown in FIG.

Explanation of symbols

2: Container lid 4: Shell 6: Liner 8: Top wall 10: Skirt wall 32: Slit 34a: High-strength bridge 34a ': Ultra-high-strength bridge 34b: Low-strength bridge 36: Internal pressure release line 48 : Mouth and neck

Claims (5)

A shell made of a thin metal plate having a circular top wall and a cylindrical skirt wall depending from the periphery of the top wall, and a synthetic resin liner disposed in the shell, and an upper end portion of the skirt wall of the shell Is provided with an internal pressure release line extending in the circumferential direction, and the internal pressure release line includes a number of slits extending in the circumferential direction at intervals in the circumferential direction and a number of bridging portions existing between the slits. In the container lid composed of
The bridging portion in the internal pressure release line has one or a plurality of relatively small circumferential widths disposed between a high strength bridging portion having a relatively large circumferential width and an adjacent high strength bridging portion. A container lid characterized by comprising a low-strength bridge.   The container lid according to claim 1, wherein one low-strength bridging portion is disposed between adjacent high-strength bridging portions.   The container lid according to claim 2, wherein all the circumferential lengths of the slits are substantially the same.   The container lid according to any one of claims 1 to 3, wherein a circumferential width of the low-strength bridging portion is 0.5 to 0.8 mm.   The high-strength bridge includes one ultra-high-strength bridge having a circumferential width larger than that of a normal high-strength bridge, and the circumferential width of the normal high-strength bridge is 2.0 to 5. 5. The container lid according to claim 1, wherein the container lid is 0 mm and the circumferential width of the ultra-high-strength bridging portion is 5.0 to 10.0 mm.

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