JP2007045452A - Container lid made of metal having internal pressure releasability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container lid made of a metal which effectively prevents the deformation of a skirt wall at a section on which slits are formed at the time of roll-pressing to the mouth section of a container from occurring in the container lid made of the metal for which the slits forming an internal pressure releasing line are formed at an upper section of the skirt wall. <P>SOLUTION: This container lid made of a metal is equipped with a shell made of a metal sheet having a circular top surface wall 7 and the skirt wall 9, and a liner made of a synthetic resin which is arranged in the shell. The skirt wall 9 is equipped with a thread forming region, and also, an annular groove 17 is formed on the upper end section of the thread forming region. In the container lid, in a section being higher than the annular groove 17 of the skirt wall 9, the internal pressure releasing line which extends circumferentially is arranged. Also, an annular bead 30 is arranged in a manner to pass a space between the internal pressure releasing line and the annular groove 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metal 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.

  The following Patent Document 1 discloses a metal 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. In addition, even when the contents are not fermented, when the container lid is attached to the mouth and neck of the container, the container internal pressure may increase due to compression of the container inner space.

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

  By the way, in the conventional internal pressure release type container lid described above, the metal thin plate shell is provided with a slit directed in the circumferential direction in the upper part of the skirt wall, and an internal pressure release line is formed by this slit. Therefore, when the container lid is wound and attached to the container mouth / neck, there is a problem that deformation occurs from the slit portion forming the internal pressure release line. That is, the container lid is wrapped around the container neck by placing a thin metal shell on the container neck and pressing the skirt wall of the shell against the container neck using an appropriate jig. Thus, the outer surface shape (for example, screw shape) of the container neck is transferred to the skirt wall. When such a jig is pressed, the skirt wall of the lower portion of the slit is likely to be deformed.

  Accordingly, an object of the present invention is to provide a metal container lid in which a slit for forming an internal pressure release line is formed in an upper part of a skirt wall, and a portion having a low strength when wound around a container mouth neck. An object of the present invention is to provide a metal container in which deformation of the skirt wall is effectively prevented.

According to the present invention, a shell made of a thin metal plate 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, In the container lid provided with a screw forming region on the skirt wall and having an annular groove formed in the upper end portion of the screw forming region,
An inner pressure release line extending in the circumferential direction is disposed in a portion of the skirt wall above the annular groove, and the annular bead passes between the inner pressure release line and the annular groove. A container lid is provided.

In the container lid of the present invention,
(1) The internal pressure release line is a low-strength region including a plurality of slits extending in the circumferential direction at intervals in the circumferential direction, and a low-strength bridging portion that exists between the slits and has a relatively small circumferential width. Including,
(2) The internal pressure release line includes the low-strength region and a high-strength region located on a circumferential extension line of the low-strength region, and the high-strength region is positioned between the plurality of slits and the slits. And a high-strength bridging portion having a larger circumferential width than the low-strength bridging portion,
(3) The internal pressure release line is formed in an arc shape, and a region between both ends in the circumferential direction of the internal pressure release line is an ultra-high-strength bridge portion having a larger circumferential width than the high-strength bridge portion. Being
(4) The ultra-high-strength bridging portion is located on the diametrically opposite side of the low-strength region of the internal pressure release line,
(5) In the internal pressure release line, a boundary portion between the low-strength region and the high-strength region has a circumferential width longer than that of the high-strength bridge portion and more than the ultra-high-strength bridge portion. Is also a reinforced bridge with a short circumferential width,
(6) The plurality of slits all have substantially the same circumferential width,
Is preferred.

In the present invention, the internal pressure release line is
(7) comprising a long slit having a length of 5 to 35% of the circumference of the skirt wall;
Is possible, and in this case,
(8) In addition to the long slit, the internal pressure release line is provided with a short circumferential slit.
Is preferred.

  In the container lid of the present invention, the internal pressure release line by the slit is formed in the skirt wall, so that when the internal pressure of the container rises excessively, the internal pressure can be released sufficiently and the container neck It is possible to effectively prevent the deformation of the skirt wall in the low strength region at the time of tightening.

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 is a half sectional side view of a preferred example of the container lid of the present invention,
FIG. 2 is a half sectional side view showing a state where the container lid of FIG.
FIG. 3 is an enlarged cross-sectional view of the main part of the container lid in the state of FIG.
FIG. 4 is a view for explaining a process of tightening the container lid of FIG. 1 around the container mouth and neck.
FIG. 5 is an enlarged view of a main part of FIG.
FIG. 6 is a half cross-sectional side view showing a state where the container lid of FIG.
FIG. 7 is an enlarged cross-sectional view showing the main part of the container lid in the state of FIG.
FIG. 8 is a development view of the skirt wall showing a pattern of an internal pressure release line formed on the skirt wall of the container lid of FIG.
FIG. 9 is a development view of the skirt wall showing another pattern of the internal pressure release line in the present invention.

  Referring to FIG. 1, the container lid of the present invention indicated as 1 as a whole is composed of a thin metal shell 3 and a synthetic resin liner 5.

  The metal thin plate shell 3 is made of, for example, an aluminum alloy having a thickness of about 0.22 to 0.26 mm, and includes a circular top wall 7 and a substantially cylindrical skirt wall 9 depending from the periphery of the top wall 7. Have.

  As is clear from FIG. 1, the lower end of the skirt wall 9 is bulged outward in the radial direction, and the bulged lower end portion is tampered with a plurality of breakable bridges 11. (TE) The skirt 13 is continuous.

  A substantially central portion of the skirt wall 9 is a screw forming region 15 in which a screw is formed by winding described later, and an annular groove 17 is formed at the upper end of the screw forming region 15. The annular groove 17 is for introducing a jig for winding.

  Above the annular groove 17 is formed a concavo-convex shape portion (Nar) 19 in which concave portions 19a and convex portions 19b alternately exist in the circumferential direction, and the upper end of the concave portion 19a (that is, the corner portion connected to the circular top wall 7). A number of slits 20 extending in the circumferential direction are formed at intervals in the circumferential direction. The slit 20 forms an internal pressure release line A. Usually, the convex part 19b of the uneven | corrugated shaped part 19 is located in the part between many slits 20. As shown in FIG. Such a large number of slits 20 generally all have substantially the same length, and have a circumferential length of about 2 to 5 mm.

  In general, as shown in FIGS. 2 and 3, such a container lid 1 is placed on a container mouth / neck part 70 and wound around the container mouth / neck part 70 by a tightening process shown in FIGS. As a result, the container mouth / neck part 70 is fixed to the container mouth / neck part 70 as shown in FIGS. 6 and 7, and the container mouth / neck part 70 is sealed.

  Returning to FIG. 1, the liner 5 is formed of an appropriate synthetic resin such as soft polyethylene, and a synthetic resin melt is supplied to the inner surface of the top wall 7, and this melt is embossed into a required shape. Can be formed conveniently. The liner 5 in the illustrated embodiment includes a relatively thin circular central portion 5a and a relatively thick annular peripheral portion 5b. As understood from FIG. 1, the central portion of the annular peripheral edge 5 b is a recessed portion that is slightly recessed.

  With reference to FIG. 2, the container neck portion 70 is made of metal, glass, hard resin, or the like. In FIG. A curl 71 is formed at the upper end of the container neck 70, a screw 73 is formed on the side surface, and a jaw 75 is formed below the screw 73.

  As shown in FIGS. 2 and 3, in order to wind the container lid 1 around the container mouth / neck part 70, the upper end (curl part 71) of the container mouth / neck part 70 is put on the container mouth / neck part 70. ), The concave portion of the annular peripheral edge 5b of the liner 5 described above faces, and the lower end of the TE skirt 13 of the container lid 1 is located below the jaw 75 of the container neck 70.

  In the above state, the winding is performed as shown in FIGS. That is, the container lid 1 placed on the container neck portion 70 is pressed against the upper end of the container mouth neck portion 70 by the outer pressing tool 77 and the shoulder portion is deformed, and the screw forming roller 79 is moved to the container lid portion. Then, the roller 79 is rotated along the thread 73 of the container mouth neck portion 70 while pressing the skirt wall 9 of the container lid 1, thereby causing the thread formation region 15 of the skirt wall 9 to enter the thread forming region 15. Then, a screw 23 is formed which is engaged with the screw 73 of the container mouth neck portion 70. On the other hand, the lower end of the TE bottom 13 of the container lid 1 is pressed against the lower side of the jaw 75 of the container neck 70 by the bottom winding roller 81 and deforms along the lower side of the jaw 75.

  As shown in FIGS. 6 and 7, the container lid 1 is fastened and fixed to the container mouth / neck part 70 by the above-described winding process, and the container lid 1 is attached to the upper end and the outer peripheral part of the container mouth / neck part 70 (curl part 71). When the annular peripheral edge portion 5b of the liner 5 is brought into close contact, the container neck portion 70 is sealed. In this state, the skirt wall 9 of the container lid 1 is screw-engaged with the outer surface of the container mouth neck portion 70, and the lower end of the TE skirt portion 13 of the container lid 1 is the jaw portion 75 of the container mouth neck portion 70. It is fixed on the lower side.

  As shown in FIGS. 6 and 7, the container lid 1 that is wound and fixed to the container neck 70 is rotated in the opening direction so that the skirt wall 9 rises. The TE skirt 13 is removed from the container mouth / neck 70, but its lower end is engaged with the lower side of the jaw 75 of the container mouth / neck 70, so that its rise is restricted, and as a result, The bridge 11 is broken and the TE skirt 13 is separated from the skirt wall 9. Therefore, in the container lid 1 removed from the container mouth / neck part 70, the TE skirt part 13 is cut off, whereby the fact of opening can be recognized. In addition, the uneven | corrugated shaped part (knurl) 19 functions as a slipper at the time of rotating the container lid 1.

  By the way, in the container lid 1 having the above structure, an internal pressure release line A is formed by the slit 20 and the bridging portion therebetween. That is, when the internal pressure of the container rises for some reason (for example, fermentation of the contents of the container), when the top wall 7 of the container lid 1 is deformed, the bridging portion between the slits 20 is immediately broken and vented. For example, inconveniences such as excessive deformation of the container lid 1 (top wall 7) and cap jumping from the container neck 70 are effectively prevented.

  However, when the slit 20 as described above is formed, the lower part of the slit 20 (the concave portion 19a of the concave-convex forming portion 19) is pulled during the winding process shown in FIG. Breaks, resulting in poor sealing. That is, in the tightening step, the screw forming roller 79 deforms the screw forming region 15 of the skirt wall 9 along the screw 75 of the container mouth / neck portion 70, so that the roller 79 is close to the annular groove 17 into which the roller 79 is introduced. The lower part (recess 19a) of the slit 20 is greatly deformed.

  In the present invention, in order to prevent the above-described inconvenience, as shown in FIGS. 1 to 7 (see particularly the enlarged view of FIG. 5 etc.), the annular bead is adjacent to the upper portion of the annular groove 17. 30 is disposed. That is, since such an annular bead 30 is formed, when the screw forming roller 19 is introduced into the annular groove 17 and tightened as shown in FIGS. The upward transmission of the deformation due to the pressing is blocked by the annular bead 30, and the deformation of the lower part (the recess 19a) of the slit 20 can be effectively prevented. For example, due to such deformation at the time of tightening The breakage of the bridging portion between the slits 20 to be performed can be effectively suppressed.

  In the present invention described above, the internal pressure release line A by the slit 20 can be various patterns.

  For example, in the example shown in FIG. 1, the internal pressure release line A is formed in an arc shape, and the internal pressure release line A includes a low-strength region A1 and a high-strength region A2, as shown in FIG. In addition, a reinforcing bridge portion 55 is formed between the low-strength region A1 and the high-strength region A2, and an ultra-high-strength bridge portion B is formed between the arc-shaped internal pressure release lines A. Has been.

  The low-strength region A1 is a low-strength bridging portion 50 having a relatively small circumferential width between the plurality of slits 20, and is easily broken due to an increase in the internal pressure of the container. The low-strength bridging portion 50 is immediately broken by the deformation of No. 7, so that the gas can be vented most easily. The circumferential length of the bridging portion 50 is about 0.5 to 0.9 mm.

  The high-strength region A <b> 2 is a high-strength bridging portion 53 that is longer than the circumferential width of the bridging portion 50 between the plurality of slits 20. This high-strength region A2 maintains a state in which cap skipping does not occur when the skirt wall 9 and the container mouth / neck portion 70 are screw-engaged even if the container internal pressure increases. This is an area provided for easy degassing in the initial stage of operation. The circumferential width of the high-strength bridging portion 53 in the high-strength region A2 is about 1.0 to 2.5 mm.

  Further, the reinforcing bridge 55 provided at both ends of the low strength region A1 (between the regions A1 and A2) is such that the fracture of the low strength region A1 (bridge 50) is high strength bridge A2 (high It is provided in order to advance to the strength bridging portion 53) at once. The circumferential length of the reinforcing bridging portion 55 is longer than that of the high-strength bridging portion 53 and is usually about 5 to 25 mm, although it varies depending on the diameter of the container lid 1 (the diameter of the top wall 7).

  Moreover, the ultra high strength region B located between the internal pressure release lines A is formed from a bridge portion having a longer circumferential length than the high strength bridge portion 55, and such an ultra high strength region is formed. By appropriately forming B, the strength can be adjusted. For example, even when the internal pressure of the container rises at once, the inconvenience (cap jumping) that the container lid 1 jumps out of the container neck 70 is reliably prevented. You can also. Such an ultra-high strength region B may be set to such a length that does not impair gas venting in the internal pressure release line A when the internal pressure of the container rises. For example, the circumferential width thereof is 5 to 25 mm. It can be set longer than the reinforcing bridge portion 55 within a range of the extent. In addition, it is preferable that the ultra-high strength region B is located on the opposite side of the top wall 7 in the diameter direction with respect to the low-strength region A1 from the viewpoint of the balance between gas venting properties and strength.

In the present invention, particularly in the internal pressure release line A as described above, the low-strength region A1 is preferably formed in an arc shape of 40 to 95 degrees with reference to the center of the top wall 7 and has such a large size. The internal pressure release line A can be formed in various patterns on condition that the arc-shaped low-strength region A1 is formed.
For example, in the pattern of FIG. 8 adopted for the container lid of FIG. 1, the super high strength region B between the internal pressure release lines A is included as follows.
55-A1-55-A2-B-A2

Of course, the above pattern is a representative example. For example, as shown in FIG. 9, the reinforcing bridge portion 55 is not formed.
A1-A2-B-A2
The internal pressure release line A can also be formed in such a pattern.

  In the example described above, the low-strength region A1 is formed by the plurality of short slits 20 and the breakable bridging portion 50. However, the low-strength region A1 can be formed by only a slit having a long circumference. That is, in such a low-strength region A2 due to such a long circumferential slit, gas can be released when the internal pressure increases without causing breakage of the bridging portion between the slits. The circumference should be 5 to 35% of the circumference of the skirt wall. Further, the internal pressure release line A can be formed by using a combination of such slits having a long peripheral length and a large number of the short slits 20 described above. However, when such a long circumferential slit is used, there is a disadvantage that the strength against a drop impact is lowered.

  In the present invention described above, the formation of the annular bead 30 effectively prevents deformation of the lower portion of the slit 20 during winding, so that the low-strength bridge portion 50 in the low-strength region A1 is particularly tightened. The breakage at the time can be effectively prevented, and therefore the gas venting property by the low strength region A1 can be effectively utilized. That is, in the conventional container lid in which the annular bead 30 is not formed, if a bridge portion having a short circumferential width between the slits is formed, this portion is likely to be broken at the time of winding. It is necessary to increase the circumferential width of the portion to increase the strength, and the degassing property when the internal pressure is increased is limited. However, in the present invention, there is no such limitation.

  The excellent effect of the present invention will be described by the following experimental example.

Example 1
1 is formed from an aluminum-based alloy thin plate having a thickness of 0.25 mm, a shell having a nominal diameter of 38 mm is formed, and soft polyethylene in a softened and melted state is then supplied to the top wall of the shell. A liner having a shape as shown in FIG. 1 was embossed to form a container lid having an annular bead as shown in FIG. The specifications of such a container lid are as follows.

Liner outer diameter: 36.3 mm
Perimeter of slit 20: 3 mm
Number of slits 20: 21 pattern of internal pressure release line A and ultra-high strength region B:
55-A1-55-A2-B-A2 (pattern of FIG. 8)
Total circumference of the low-strength region A1: 65 degrees Low-strength bridge 50:
Circumferential width: 0.70mm (Tensile strength 60N)
Number: 2 High strength bridge 53:
Circumferential width: 1.4mm
Reinforcement bridge 55:
Circumferential width: 5mm
Number: 2 Circumferential width of the super-high-strength bridging portion 55: 20 mm

  Prepare a container made of aluminum thin plate with an inner volume of 310 ml and a nominal diameter of 38 mm, which is sold by Mitsubishi Materials Co., Ltd. (the outer curl had an outer diameter of 33.5 mm). The container lid was wound around the neck as shown in FIG. When 50 container lids were wound in exactly the same manner, no breakage of the bridging portion between the slits was observed.

(Example 2)
A container lid was produced in the same manner as in Example 1 except that the use of the internal pressure release line A of the container lid was changed as follows, and a winding test was performed in the same manner.
Low strength bridge 50:
Circumferential width: 0.73 mm (tensile strength 65 N)
Number: 2

  As a result of the winding test, no breakage of the bridging portion between the slits was observed in any of the 50 container lids.

(Comparative Example 1)
A container lid was prepared in the same manner as in Example 1 except that the annular bead was not formed, and a winding test was performed in the same manner.
In addition, the pattern of the internal pressure release line A in this example is exactly the same as that of the first embodiment. For example, the low-strength bridging portion 50 is as follows.
Low strength bridge 50:
Circumferential width: 0.7mm (Tensile strength 60N)
Number: 2

  As a result of the tightening test, breakage of the low-strength bridging portion 50 between the slits was recognized for four of the 50 container lids.

(Comparative Example 2)
A container lid was prepared in the same manner as in Example 1 except that the annular bead was not formed and the use of the internal pressure release line A of the container lid was changed as follows, and the winding test was performed in the same manner. .
Low strength bridge 50:
Circumferential width: 0.75mm (tensile strength 70N)
Number: 2

  As a result of the tightening test, one of the 50 container lids was found to break the low-strength bridge 50 between the slits.

  From the above results, it can be seen that the formation of the annular bead can effectively prevent breakage at the time of winding even in a portion where the distance between the slits between the slits is short.

  That is, when an annular bead is formed as in the present invention, a low-strength bridging portion with a short gap between slits can be formed. Is done effectively. For example, in the container lid of Example 2, when the internal pressure was 0.86 MPa, the low-strength bridging portion 50 was broken and degassing was performed.

  On the other hand, in the container lid of Comparative Example 2 in which the annular bead was not formed, the bridging portion was broken for the first time when the internal pressure increased to 0.97 MPa, and the gas was vented.

The half section side view of the suitable example of the container lid of this invention. The half section side view which shows the state which covered the container lid of FIG. 1 on the container neck. Sectional drawing which expands and shows the principal part with the container opening neck in the container lid of the state of FIG. The figure for demonstrating the process of winding the container lid of FIG. 1 around a container mouth neck. The principal part enlarged view of FIG. The half section side view which shows the state which wound the container lid of FIG. 1 around the container neck. Sectional drawing which expands and shows the principal part of the container lid in the state of FIG. FIG. 2 is a development view of a skirt wall showing a pattern of an internal pressure release line formed on the skirt wall of the container lid of FIG. 1. The expanded view of the skirt wall which shows the other pattern of the internal pressure release line in this invention.

Explanation of symbols

1: Container lid 7: Top wall 9: Skirt wall 17: Annular groove 20: Slit 30: Annular bead 50: Low strength bridge 53: High strength bridge 55: Reinforced bridge A: Internal pressure release line A1: Low strength region A2: High strength region B: Ultra high strength region

Claims (9)

A thin sheet metal 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, the skirt wall of the shell comprising: In a container lid provided with a screw forming region and having an annular groove formed in the upper end portion of the screw forming region,
An inner pressure release line extending in the circumferential direction is disposed in a portion of the skirt wall above the annular groove, and the annular bead passes between the inner pressure release line and the annular groove. The container lid characterized by the above-mentioned.   The internal pressure release line includes a low-strength region including a plurality of slits extending in the circumferential direction at intervals in the circumferential direction and a low-strength bridge portion that exists between the slits and has a relatively small circumferential width. Item 2. The container lid according to Item 1.   The internal pressure release line includes the low-strength region and a high-strength region located on a circumferential extension line of the low-strength region, and the high-strength region is located between the slits and the slits and The container lid of Claim 2 comprised from the high intensity | strength bridge part with a larger circumferential direction width than a low intensity | strength bridge part.   The internal pressure release line is formed in an arc shape, and a region between both ends in the circumferential direction of the internal pressure release line is an ultra-high-strength bridge portion having a larger circumferential width than the high-strength bridge portion. The container lid according to 2 or 3.   The container lid according to claim 4, wherein the ultra-high-strength bridging portion is located on the diametrically opposite side of the low-strength region of the internal pressure release line.   In the internal pressure release line, a boundary portion between the low-strength region and the high-strength region has a longer circumferential width than the high-strength bridge portion and a circumferential direction more than the ultra-high-strength bridge portion. The container lid according to claim 4, wherein the container lid is a short reinforcing bridge.   The container lid according to claim 2, wherein all of the plurality of slits have substantially the same circumferential width.   The container lid according to claim 1, wherein the internal pressure release line is constituted by a long slit having a length of 5 to 35% of a circumferential length of the skirt wall.   The container lid according to claim 8, wherein the internal pressure release line is provided with a short circumferential slit in addition to the long slit.

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