JP2004331190A - Container lid having inner pressure releasing characteristic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container lid (2) wherein a sharp metal fracture edge is not generated resulting from an inner pressure releasing, and there is no fear for that the sealing of the neck section of a container is damaged resulting from a collision of foreign matter or the like, and in addition, even when an inner pressure releasing value varies resulting from a fitting position error or the like, the inner pressure releasing value can surely be set within an allowable range. <P>SOLUTION: This container lid (2) is constituted in such a manner that at least one inner pressure releasing notch (38) which extends radially is formed on the close sealing surface of a liner (6). In a region higher than a threaded section (25) in a skirt wall (10) of a lid body (4), an inner pressure release accelerating slit (30) which extends circumferentially is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a container lid composed of a thin metal plate lid body and a synthetic resin liner, which has an internal pressure release characteristic of automatically releasing the internal pressure when the container internal pressure becomes excessive.
[0002]
[Prior art]
BACKGROUND ART As a container for storing a fruit juice beverage or a carbonated beverage containing natural juice, a container made of a thin metal plate, glass or synthetic resin having an external thread formed on an outer peripheral surface is used. And, as a container lid for such a container, a main body made of a thin metal plate having a top wall and a skirt wall hanging down from a periphery of the top wall, and a synthetic resin liner disposed on the inner surface of the top wall of the lid main body The container lid composed of the above is widely used for practical use. When a container lid is attached to the mouth and neck of the container to seal the mouth and neck, a female thread is formed in the thread on the skirt wall of the lid body corresponding to the male thread of the mouth and neck. .
[0003]
The container lid as described above seals the mouth and neck of the container sufficiently in a normal state, but when the container internal pressure rises excessively and exceeds a predetermined value, for example, 0.4 MPa, the internal pressure is released. It is important to have open characteristics. For example, when a juice beverage containing natural juice is contained in the container, the container is once opened and the juice beverage is exposed to the atmosphere, and then the container lid is attached to the mouth and neck of the container again to reseal the mouth and neck. Occasionally, the pressure inside the container may rise excessively due to the fermentation phenomenon of the juice beverage. If the internal pressure of the container is raised beyond a predetermined value without being released, the container cover is rapidly opened when the container cover is rotated slightly in the opening direction to reopen the mouth and neck of the container. There is a possibility that a situation in which the robot is separated from the neck and flies may occur.
[0004]
In Patent Document 1 below, at least one internal pressure release notch is formed on a close sealing surface of a synthetic resin liner, and when the internal pressure of the container rises excessively, the top wall of the lid body is deformed in a convex shape and the internal pressure release notch is formed. Discloses a container lid configured to release the internal pressure of the container through the container lid. Further, in the following Patent Document 2, a large number of slits extending in the circumferential direction at a slight interval in the circumferential direction are formed in the upper portion of the skirt wall of the lid body, that is, in the region above the main portion where the female thread is formed. When the internal pressure of the container rises excessively, the so-called bridging portion remaining between the many slits is broken, and at least a part of the upper portion of the lid body is deformed upward, thereby releasing the internal pressure of the container. A container lid configured as such is disclosed. Further, in Patent Document 3 below, an annular bulging portion bulged radially outward is formed at the upper part of the skirt wall of the lid body, and when the container internal pressure rises excessively, the cross-sectional shape of the annular bulging portion is increased. There is disclosed a container lid configured to be deformed from an arc shape to a linear shape so that the upper portion of the lid body is entirely displaced upward, thereby releasing the internal pressure of the container.
[0005]
[Patent Document 1]
Japanese Patent Publication No. 4-40268 [Patent Document 2]
Japanese Utility Model Publication No. 7025318 [Patent Document 3]
JP-A-8-80962
[Problems to be solved by the invention]
However, in the container lid disclosed in Patent Literature 1, the opening internal pressure value fluctuates relatively largely due to an error in the mounting position of the container lid with respect to the mouth and neck, and due to the mounting position error and the like. There is a problem that the opening internal pressure value becomes too small to obtain required sealing characteristics, or that the opening internal pressure becomes too high to obtain the required internal pressure releasing characteristics. Further, in the container lid disclosed in Patent Document 2, when the bridge portion is broken when the internal pressure is released, a sharp metal rupture edge is generated, and a sharp metal rupture edge is generated by upward deformation of the lid body. Is exposed, and there is a problem that the finger of the user is likely to be damaged. Furthermore, in the container lid disclosed in Patent Document 3, since the bulging portion of the lid main body is protruded outward in the radial direction, there is a large possibility that the bulging portion may collide with foreign matter. There is a problem that the protrusion may be easily deformed and the seal of the mouth and neck of the container may be damaged.
[0007]
The present invention has been made in view of the above-mentioned facts, and a main technical problem thereof is that a sharp metal fractured edge is not generated due to internal pressure release, and a container is also generated due to foreign matter collision or the like. In addition to the possibility that the seal of the mouth and neck may be damaged, even if the internal pressure release value fluctuates due to a mounting position error, etc., the internal pressure release value will surely fall within the allowable range. To provide a customized container lid.
[0008]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have formed an internal pressure release promoting slit extending in the circumferential direction in a region above the screw portion in the skirt wall of the lid body, and when the container internal pressure excessively increases, the internal pressure release promoting slit is formed. If the lid body is deformed around the periphery of the container and the hermetic sealing surface of the liner is locally separated from the mouth and neck to release the internal pressure of the container, sharpness is caused by the release of the internal pressure. It has been recognized that the internal pressure release value can be set sufficiently precisely without producing metal fracture edges. However, when the internal pressure release promoting slit is formed to release the internal pressure of the container, usually, in order to reduce the internal pressure release value to a required optimum value, the circumferential length of the internal pressure release promoting slit is considerably long. For example, when it is necessary to reduce the length to 10 mm or more, and when the length of the internal pressure release promoting slit is set to a considerable length, for example, the impact applied to the container lid when handled in a vending machine causes He also recognized that the neck seals tended to break easily. Based on such recognition, the present inventors have formed at least one radially extending internal pressure release notch on the close sealing surface of the liner, and in the region above the thread portion of the skirt wall of the lid body. An internal pressure release accelerating slit having a length of 3 to 8 mm, which is shorter than a predetermined length, that is, a length at which the seal of the mouth and neck is easily damaged by impact, is formed, and there is an error in the open internal pressure value due to the presence of the internal pressure release notch. If the internal pressure is set to be higher than the allowable lower limit even if it occurs, and the internal pressure for opening due to the internal pressure release accelerating slit is set higher than the optimum value but lower than the allowable upper limit, the internal pressure of the internal pressure is usually released. Due to the presence of the notch, the desired value is obtained, but if the open internal pressure value due to the presence of the internal pressure release notch exceeds the allowable upper limit due to the mounting position error etc., it is due to the presence of the internal pressure release promoting slit. do it Internal pressure of the container is opened in the following volume upper limit value, thus found that it is possible to achieve the above principal object.
[0009]
That is, according to the present invention, as a container lid for achieving the above-mentioned main technical problem, a metal thin plate lid main body having a top wall and a skirt wall hanging down from the periphery of the top wall, and a lid of the top wall of the lid main body A synthetic resin liner disposed on the inner surface, and a container cover having a mouth-and-neck portion having an external thread formed on the outer peripheral surface. At least one internal pressure release notch extending in the direction of the container is formed, and a female screw thread is formed in the skirt wall of the lid body corresponding to the male screw thread formed in the mouth and neck of the container. An internal pressure release promoting slit having a circumferential length of 3 to 8 mm is formed in a region above the ridge, and when the container internal pressure rises excessively, the top wall of the lid body is deformed in a convex shape. The internal pressure of the container is released through the internal pressure release notch. Or internal pressure of the container is lid body deforms around the periphery of the internal pressure release promotes the slit is opened, the container closure, wherein provided that.
[0010]
The internal pressure release notch preferably has a width of 0.2 to 0.4 mm. Preferably, a plurality of the internal pressure release notches are formed at intervals in the circumferential direction, and a plurality of the internal pressure release promoting slits are formed at intervals in the circumferential direction. Preferably, the liner has an outer peripheral edge which is brought into close contact with the upper end of the outer peripheral surface of the mouth and neck portion of the container, and the internal pressure release notch is preferably formed in a close sealing surface of the outer peripheral edge.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a container lid configured according to the present invention will be described in more detail with reference to the accompanying drawings.
[0012]
Referring to FIG. 1, the container lid indicated by reference numeral 2 is composed of a thin metal sheet lid body 4 and a synthetic resin liner 6. The lid body 4, which is preferably formed of an aluminum-based alloy thin plate having a thickness of about 0.22 to 0.26 mm, comprises a circular top wall 8 and a cylindrical skirt wall 10 hanging down from the periphery of the top wall 8. Having. A rupture line 12 extending in the circumferential direction is formed at a lower portion of the skirt wall 10. The skirt wall 10 has a main portion 14 above the rupture line 12 and a tamper-evident hem portion 16 below the rupture line 12. It is partitioned. An annular bulge 18 slightly bulged outward in the radial direction is formed at a lower portion of the skirt wall 10, and an axially central portion of the annular bulge 18 is provided at an appropriate interval in a circumferential direction. A plurality of slits 20 extending in the circumferential direction are formed, and the breaking line 12 is defined by the plurality of slits 20 and a plurality of bridging portions 22 remaining between the slits 20.
[0013]
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. A region below the annular groove 24 in the main portion 14 of the skirt wall 10 is a screw portion 25 on which a female screw is formed later. The annular groove 24 is used when a female screw is formed on the screw portion 25. Used to position the strip forming tool. In an area above the annular groove 24 in the main portion 14 of the skirt wall 10, a concave portion 26 and a convex portion 28 for preventing slippage when a finger is hung to rotate the container lid 2 are alternately repeated. A shape part is formed. In the illustrated container lid 2 constructed in accordance with the present invention, three wide recesses 26a located at equal intervals in the circumferential direction (only one of the three wide recesses 26a is shown in the drawing. ), The circumferential width Wa is larger than the circumferential width w of the other concave portion 26, for example, about three times the circumferential width W. An internal pressure release promoting slit 30 extending in the circumferential direction is formed at the upper end of each of the three wide concave portions 26a. It is important that the circumferential length of the internal pressure release promoting slit 30, that is, the circumferential width Wa of the wide concave portion 26a in the illustrated embodiment is 3 to 8 mm.
[0014]
In the illustrated embodiment, three wide recesses 26a are formed at equal intervals in the circumferential direction and three internal pressure release promoting slits 30 are formed. However, if desired, one, two, or four slits 30 are formed. The internal pressure release promoting slit 30 described above can also be formed. According to the experience of the present inventors, it is generally preferable to form two to four internal pressure release promoting slits 30 at equal intervals in the circumferential direction. In the illustrated embodiment, the internal pressure release promoting slit 30 is formed at the upper end of the concave portion 26a. However, if desired, the internal pressure release promoting slit 30 may be formed at an appropriate position without being limited to the upper end of the pressing portion 26a. it can. Further, in a case where a cleaning step of flowing the cleaning liquid into the mouth and neck of the container through the slit formed in the container lid 2 after attaching the container lid 2 to the mouth and neck of the container as described later is performed, In addition to the wide recess 26a having a relatively large circumferential width Wa in order to promote the inflow of air, a slit extending in the circumferential direction can be formed at the upper end of the normal recess 26.
[0015]
A liner 6 that can be molded from a suitable synthetic resin such as soft polyethylene is provided on the inner surface of the top wall 8 of the lid body 4. The liner 6 can be provided by supplying a synthetic resin material to a required position on the inner surface of the top wall 8 and stamping it into a required shape. In this case, the peripheral edge of the liner 6 is not adhered or weakly adhered to the inner surface of the top wall 8, but the impact resistance is improved or the container lid 2 once detached from the mouth and neck of the container is reattached to the container. This is advantageous from the viewpoint of reducing the required torque for mounting on the mouth and neck. If desired, a separately formed liner can be at least partially adhered to the inner surface of top wall 8. Continuing with FIG. 1 and FIGS. 2 and 3, the liner 6 in the illustrated embodiment has a disk shape as a whole, and has a thin central portion 32 and an annular ridge 34 surrounding the thin central portion 32. And a seal portion 36 further extending radially outward from the annular ridge 34. The thickness of the seal portion 36 is gradually increased radially outward, and the close sealing surface, ie, the lower surface, is slightly downwardly inclined radially outward. As will be further described below, the inner peripheral edge of the seal 36 is in close contact with the top surface of the mouth and neck of the container, and the outer peripheral edge of the seal 36 is in close contact with the upper end of the outer peripheral surface of the mouth and neck of the container. In the container lid 2 constructed in accordance with the present invention, at least one radially extending internal pressure release notch 38 is formed on the lower surface of the outer peripheral edge of the seal portion 36 of the liner 6, that is, on the close seal surface. is important. In the embodiment shown, three internal pressure release notches 38 are formed at equal intervals in the circumferential direction, as can be understood by referring to FIG. The internal pressure release notch 38 may be formed in alignment with the position of the internal pressure release promoting slit 30 described above, or may be formed displaced from the position of the internal pressure release promoting slit 30 described above. The circumferential width of the internal pressure release notch 38 may be about 0.2 to 0.4 mm. The depth of the internal pressure release notch 38 may be about 0.1 to 0.3 mm.
[0016]
FIG. 4 also shows the mouth and neck 40 of the container to which the container lid 2 is applied. The container, which can be conveniently formed from an aluminum-based alloy sheet or a chromic steel sheet, has a substantially cylindrical mouth and neck 40. The upper end of the mouth-neck portion 40 is shaped like a truncated cone which is inclined inward in the radial direction upward, and an outer winding curl 42 is formed at the upper end. A male thread 44 is formed at an axially intermediate portion of the mouth and neck part 40, and an annular locking jaw 46 bulging radially outward is formed below the male thread 44. The container lid 2 configured according to the present invention is not limited to the container having the mouth and neck portion 40 in the illustrated form, but has a mouth and neck portion in another form formed of a thin metal plate, glass, or a suitable synthetic resin. It goes without saying that it can be applied to containers.
[0017]
With reference to FIG. 4 together with FIG. 1, when the container lid 2 is attached to the mouth and neck 40 and the mouth and neck 40 is sealed, the container lid 2 is fitted over the mouth and neck 40. The container lid 2 is pressed downward at a required pressure to bring the inner peripheral edge of the seal portion 36 of the liner 6 into close contact with the top surface of the curl 42 formed at the upper end of the mouth and neck portion 40. An annular ridge 34 formed on the liner 6 is advanced into the mouth and neck portion 40 and helps to position the container lid 2 concentrically with respect to the mouth and neck portion 40. Next, the boundary area between the top wall 8 and the skirt wall 10 of the lid body 4 is deformed downward and inward in the radial direction to form an immersed part 48, and the screw part 25 in the main part 14 of the skirt wall 10 is A female thread 50 is formed corresponding to the male thread 44 of the neck 40, and the lower part of the tamper-evident hem 16 is displaced radially inward to form an annular locking jaw 46 of the mouth and neck 40. Lock it. In FIG. 4, the state before the deformation is applied to the container lid 2 is indicated by a two-dot chain line, and the state after the deformation is applied is indicated by a solid line. 4 and 5, when the boundary area between the top wall 8 and the skirt wall 10 of the lid body 4 is deformed downward and inward in the radial direction to form the immersion part 48, the sealing part of the liner 6 is formed. The outer peripheral edge at 36 is forced downward and is brought into close contact with the outer peripheral surface of the curl 42 formed at the upper end of the mouth and neck portion 40 (therefore, the upper end portion of the outer peripheral surface of the mouth and neck portion 40). Conveniently, the inner end of the internal pressure release notch 38 formed on the outer peripheral edge of the seal portion 36 is substantially aligned with the upper end of the outer peripheral surface of the curl 42.
[0018]
When opening the mouth and neck portion 40 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 50 formed on the skirt wall 10 moves along the male thread 44 formed on the mouth and neck portion 40, and thus does not rise with rotation. However, the tamper-evident skirt 16 is locked by the annular locking jaw 46 and therefore is prevented from rising, thus creating considerable stress in the rupture line 12, and more specifically, the bridging portion 22 thereof, The portion 22 is broken to separate the tamper-evident hem 16 from the main portion 14 of the skirt wall 10. Thereafter, the container lid 2 is lifted with rotation except for the tamper-evident hem 16 and detached from the mouth and neck 40, and thus the mouth and neck 40 is opened. If it is desired to temporarily re-seal the opened mouth and neck 40, the container lid 2 detached from the mouth and neck 40 is again fitted to the mouth and neck 40 and closed in the closing direction, ie, FIG. , The female screw 50 of the container lid 2 may be screwed into the male screw 44 of the mouth-neck portion 40. When the female thread 50 is sufficiently screwed into the male thread 44, the seal portion 36 of the liner 6 is brought into close contact with the top surface and the outer peripheral surface of the curl 42 of the mouth-neck portion 40, and the mouth-neck portion 40 is sealed again. You.
[0019]
When the content contained in the container is, for example, a fruit juice beverage containing natural juice, the mouth and neck 40 is once opened as described above to expose the content to the atmosphere, and then the mouth and neck by the container lid 2. When the container is sealed again, the internal pressure of the container may rise abnormally due to the fermentation phenomenon of natural juice. Also, even before the mouth and neck 40 is once opened, if the contents contained in the container are carbonated beverages, the container internal pressure may rise abnormally if the container is heated significantly by being exposed to sunlight or the like. There is. In the container lid 2 constructed according to the present invention, when the container internal pressure excessively rises and exceeds a predetermined value, for example, 0.4 MPa, as shown in FIG. Is deformed into a ridge, and as a result, the internal pressure of the container is released through the internal pressure release notch 38 formed in the seal portion 36 of the liner 6. Thus, according to the experience of the present inventors, the internal pressure release through the internal pressure release notch 38 as described above requires the relative position of the seal portion 36 of the liner 6 with respect to the curl 42 of the mouth and neck portion 40 and the like. There is a problem that the internal pressure release value fluctuates relatively largely due to a slight fluctuation. In the container lid 2 configured according to the present invention, when the internal pressure release value due to the internal pressure release notch 38 fluctuates due to the above-described factors, the internal pressure release value may be higher than the allowable upper limit value, but may be higher than the allowable lower limit value. Is set so as not to be lowered. If the internal pressure of the container does not release through the internal pressure release notch 38 even if the internal pressure of the container continues to increase and exceeds, for example, 0.6 MPa, as shown in FIG. The lid main body 4 is deformed around the internal pressure release promoting slit 30, and the sealing action by the liner 6 is locally damaged by such deformation, so that the container internal pressure is released. The internal pressure release value resulting from the deformation of the lid body 4 centering on the internal pressure release promoting slit 30 can be defined sufficiently precisely by setting the circumferential length of the internal pressure release promoting slit 30 to a predetermined value. On the other hand, according to the experience of the present inventors, when the circumferential length of the internal pressure release promoting slit 30 is set relatively long, for example, when the container internal pressure exceeds 0.4MP, the lid body 4 causes the internal pressure release promoting slit 30 to If the container is deformed as a center and the internal pressure of the container is set to be released, for example, when a shock is applied to the container lid 2 by handling in a vending machine, the seal of the mouth and neck portion 40 of the container is damaged. There is a possibility that it will end. Therefore, it is desired that the internal pressure release value resulting from the deformation of the lid body 4 centering on the internal pressure release promoting slit 30 be set to a relatively large value, although not more than the allowable upper limit value.
[0020]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the container lid of this invention, a sharp metal fracture | rupture edge is not produced | generated by internal pressure release, and there is also a possibility that the seal of the mouth and neck of a container may be damaged by collision of a foreign material etc. In addition to the above, even if the internal pressure release value fluctuates due to a mounting position error or the like, the internal pressure release value surely falls within the allowable range.
[Brief description of the drawings]
FIG. 1 is a front view partially showing a cross section of a container lid constructed according to the present invention before being attached to the mouth and neck of the container.
FIG. 2 is an enlarged partial sectional view showing a part of the container lid of FIG. 1 in an enlarged manner.
FIG. 3 is a bottom view of the container lid of FIG. 1;
FIG. 4 is a front view showing a part of the container lid shown in FIG. 1 in cross section in a state where the container lid is attached to the mouth and neck of the container.
FIG. 5 is a partially enlarged cross-sectional view showing a part of the container lid shown in FIG. 1 in a state of being attached to the mouth and neck of the container.
6 is a partial slope view showing a state in which when the container internal pressure rises excessively, the lid body in the container lid shown in FIG. 1 is deformed around the internal pressure release promoting slit and the container internal pressure is released.
[Explanation of symbols]
2: Container lid 4: Lid body 6: Liner 8: Top wall 10: Skirt wall 30: Internal pressure release promoting slit 36: Liner seal 38: Internal pressure release notch 40: Container neck and neck

Claims (5)

A metal sheet lid body having a top wall and a skirt wall hanging down from the periphery of the top wall; and a synthetic resin liner disposed on the inner surface of the top wall of the lid body, and a male screw on the outer peripheral surface. In a container lid applied to a container having a mouth and a neck where a ridge is formed,
At least one radially extending internal pressure release notch is formed in the close sealing surface of the liner, and corresponds to a male thread formed in the mouth and neck of the container in the skirt wall of the lid body. An internal pressure release promoting slit having a circumferential length of 3 to 8 mm is formed in a region above the thread portion where the female thread is formed, and when the container internal pressure rises excessively, the lid body is opened. The top wall is deformed in a convex shape to release the container internal pressure through the internal pressure release notch, or the lid main body is deformed around the periphery of the internal pressure release promoting slit to release the container internal pressure. Characteristic container lid. The container lid according to claim 1, wherein the internal pressure release notch has a width of 0.2 to 0.4 mm. 3. The container lid according to claim 1, wherein a plurality of said internal pressure release notches are formed at intervals in a circumferential direction. The container lid according to any one of claims 1 to 3, wherein a plurality of the internal pressure release promoting slits are formed at intervals in a circumferential direction. The liner according to any one of claims 1 to 3, wherein the liner has an outer peripheral edge closely contacted with the upper end of the outer peripheral surface of the mouth and neck of the container, and the internal pressure release notch is formed in a close sealing surface of the outer peripheral edge. The container lid according to any one of the above.

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