KR100222767B1 - Metallic container lid and device for forming weakening line thereof - Google Patents

Abstract

The perforation line of the metal container stopper consists of a plurality of slits extending circumferentially at intervals in the circumferential direction and a plurality of bridge portions respectively positioned between the slits. The radial deformation amount between the upper and lower slits gradually decreases in the circumferential direction on both sides of the bridge portion toward the bridge portion. The notch corresponding to the bridge portion is formed in the outer blade which is fitted to the tear line forming device. The inclined portions extending both sides in the circumferential direction with the outward inclination in the radial direction are formed in the circumferential both side portions of the notch.

Description

Metal container stopper and its perforation device

1 is a side view showing, in partial cross section, a container closure of a preferred embodiment of the structure according to the invention;

FIG. 2 is a plan view showing the outer blade member of the preferred embodiment provided on a perforation line forming device for use in the manufacture of the container closure of FIG.

FIG. 3 is a partial schematic view showing notches (corresponding to brittle bridge portions) in the outer blades of the outer blade member of FIG.

FIG. 4 is a partial schematic view showing notches (corresponding to brittle bridging portions) in the outer blades of the outer blade member of FIG.

FIG. 5 is a partial cross sectional view showing the shearing operation of the outer blade of the perforation line forming apparatus of FIG.

FIG. 6 is a partial cross-sectional view showing the formation of an easy-to-break bridge portion attributed to the notch of the outer blade in the perforation line forming apparatus of FIG.

FIG. 7 is a partial cross-sectional view showing the operation of the score forming tool portion of the outer blade member in the perforation line forming apparatus of FIG.

FIG. 8 is a partial cross-sectional view showing the action of the bending tool portion of the outer braid member in the perforation line forming apparatus of FIG.

FIG. 9 is a partial schematic view showing an adjacent area of a bridge portion that is easily broken within the perforation line of the container plug of FIG. 1; FIG.

Fig. 10 is a partial schematic view showing adjacent areas of bridge portions that are easily broken within the perforations of conventional container stoppers.

11 is a side view showing, in partial cross section, a state in which the container closure of FIG. 1 is installed on the neck of the container.

FIG. 12 is a side view showing a state in which the container closure of FIG. 11 falls from the neck of the container. FIG.

FIG. 13 is a micrograph showing the adjacent area of a brittle portion within a perforation line of a container stopper formed in the examples provided below.

FIG. 14 is a micrograph showing a broken state of a bridge portion easily broken within the perforation line of the container stopper shown in FIG. 13. FIG.

FIG. 15 is a micrograph showing the adjacent area of the brittle portion easily breakable within the perforation line of the container stopper formed in the comparative example provided below.

FIG. 16 is a micrograph showing a broken state of a bridge portion that is easily broken within the perforation line of the container stopper shown in FIG. 15. FIG.

* Explanation of symbols for main parts of the drawings

2: container stopper 4: top panel wall

6: skirt wall 8: convex

10: perforation line 16: slit

18: Bridge portion easy to break 20: Bridge portion difficult to break

22: Score 28: Sealing Liner

30 seal part 32 outer blade member

34: outer blade 38: notch

40, 42, 44: inclined portion 46: bending tool portion

48: Score forming tool part

The present invention relates to a metal container stopper having a circumferentially extending tear line formed in the skirt wall and a tear line forming device for forming a circumferentially extended cutout line in the skirt wall of the metal container stopper.

Metal container closures with so-called anti-theft formation are widely used in containers such as glass or plastic bottles for foodstuffs and beverages. This container closure is formed of a metal sheet, such as an aluminum based alloy sheet, chromic acid treated steel sheet or tin plate, and consists of a cylindrical top panel wall and a cylindrical skirt wall extending downward from the peripheral edge of the top panel wall. Inside the top panel wall is provided a sealing liner formed of a suitable plastic material. The skirt wall has a circumferential extended perforation line and is divided into a main portion above the perforation line and a base portion below the perforation line. The perforation line consists of a plurality of slits extending at intervals in the circumferential direction and a plurality of bridge portions respectively positioned between the slits. In the cut line, all the bridge portions are bridge portions that are easily broken, or one (or two or more) of the bridge portions that are easily broken are not easy bridge portions, that is, bridge portions are difficult to break. As used herein, the term “fragile bridge portion” means a relatively low strength bridge portion that breaks when the container closure rotates relative to the vessel to open the vessel. The term “fragile bridge portion” refers to a bridge of relatively high strength that does not break when the container closure rotates relative to the vessel to open the vessel. If there is a bridge portion that is difficult to break, a score extending in the axial direction is formed in the anti-theft base portion with respect to the bridge portion that is difficult to break.

The above-mentioned perforation line consists of the perforation line forming apparatus of the type described in JP 43-17920, 45-14396, 47-9636, and 57-15205. This perforation forming apparatus has an arcuate or circular outer blade having a substantially rectangular notch formed at a distance corresponding to the bridge portion. The skirt wall of the container stopper is affected by the rotation of the skirt wall side (hereinafter referred to as "the blade wall"). , “Working surface”) is deformed inward in the radial direction. As a result, shearing action occurs and slits are formed. At the boundary between the slit and the bridge, the skirt wall is axially sheared over some length. Thus, the bridge portion has some length in the axial direction.

The container stopper is provided in a container of a type in which a male screw and a coupling flange under the male screw are formed on an outer circumferential surface of a neck. When the container closure is fitted on the neck of the container to seal the neck, the container closure is placed on the neck and the outer surface of the top panel wall of the container closure is pressed so that the sealing liner is in close contact with the upper end of the neck. As the state is maintained, female threads are formed in the main portion of the skirt wall of the container stopper along the male threads of the neck. At the same time, the lower end of the skirt wall of the container stopper, ie the lower end of the anti-theft base part, is bent inward to engage the engagement flange of the neck. When opening the container, the container stopper is rotated in the opening direction. The rotation causes the female thread of the container plug to move along the male thread of the neck to move. Thus, the container closure moves upward relative to the neck. On the other hand, the anti-theft base portion of the container stopper engages with the engagement flange of the neck and is prevented from rising, thereby generating significant stress in the cutout line, in particular in the bridge portion thereof. As a result, the bridge part which is easy to break in a perforation line | wire breaks. If all bridge portions are fragile bridge portions, the anti-theft base portion is separated from the main portion of the skirt wall due to its damage. If the bridge portion is provided with a bridge portion that is difficult to break, the bridge portion that is difficult to break remains undamaged, while the axially extending score in the anti-theft base portion is broken, so that the anti-theft base portion has an end portion from an endless annular shape. It is cut open in the form of a belt. Thus, with the anti-theft base being held on the neck (when all the bridge parts are fragile) or the anti-theft base being connected to the main part of the skirt wall by a brittle bridge, the container closure is It is cherry. When the container stopper is remounted on the neck to reseal the neck, the container stopper having the anti-theft base portion connected to the main portion of the skirt wall by the bridge portion which is difficult to break is broken to separate the anti-theft base portion from the main portion of the skirt wall. It is necessary to pull the anti-theft base portion further so as to break this difficult bridge portion.

Conventional container closures of the type described above have the following problems. In other words, if the easy-to-break bridge portion is broken at the time of opening the container, or if the difficult-to-break bridge portion is broken after opening the container, the bridge portion is serrated, so that the sharp remaining bridge portion projecting downward from the main portion of the skirt wall is formed. Is generated. If the user's finger, etc. touches the sharp residual bridge, they are injured.

In order to solve the above problem, Japanese Patent Laid-Open No. 2-191163 has proposed that bending is provided in a bridge portion extending axially over a certain length along an upper edge. This bending breaks along the upper edge, which prevents the formation of sharp residues. However, if the bridging is easy to break, especially if sufficient bending is provided to ensure that breakage occurs along the upper edge, then this bending itself tends to cause the bridging of the bridge, or the bridging may be It tends to break when it is mounted on the neck of a person. Therefore, the manufacture of certain container closures requires that the degree of bending be precisely controlled or handled to minimize mistakes in bending operations. This may include slowing down the manufacturing speed or increasing the production cost.

It is an object of the present invention to improve the shape of the perforation line formed in the skirt wall of the metal container stopper so that at least the breakable line in the perforation line is not broken in a serrated form, and thus, the sharp residue is formed in the bridge part which is easy to break. It does not solve the above-mentioned problems by increasing the manufacturing speed and reducing the production cost.

It is another object of the present invention to provide an improved tear line forming apparatus capable of forming the cut line having an improved shape in the skirt wall of a metal container stopper.

In the perforation line of the container cap conventionally, the radial deformation amount between the upper and lower parts of each slit was constant. In the container closure of the present invention, the radial deformation amount between the upper and lower portions of the slit gradually decreases in the circumferential direction on both sides of the easily breakable bridge portion toward the easily breakable bridge portion to solve the above technical problem.

According to the invention, there is provided a metal container stopper comprising an upper panel wall and a cylindrical skirt wall extending downward from the circumferential edge of the upper panel wall, the skirt wall having a perforation line extending in the circumferential direction, the cut line It consists of a plurality of slits extending at intervals in the circumferential direction and a plurality of bridges positioned between the slits, each of the slits is formed by shearing the upper and lower slits in a radially deformed form, at least some of the plurality of bridges Is a brittle bridging portion, wherein the radial deformation amount between the upper and lower portions of the slit is gradually reduced in the circumferential direction on both sides of the brittle brittle portion toward the brittle brittle portion.

The radial deformation amount between the upper and lower portions of the slit is preferably zero at both ends in the circumferential direction of the bridge portion that is easily broken.

Further, in the present invention, in order to form the cutout line of the above-described form, both side portions of the notch formed at intervals corresponding to the bridge portion, at least the brittle portion, which are easily broken, in the outer blade of the cutout forming apparatus in the conventional radial direction Rather than an almost straight portion, it is formed in an inclined form extending both sides in the circumferential direction with an outward inclination in the radial direction.

The present invention also provides a perforation forming device for forming a circumferential perforation in a cylindrical skirt wall of a metal container stopper having an upper panel wall, wherein the skirt wall extends downwardly from the circumferential wall edge of the top panel wall, and the circumferential perforation line. Is composed of a plurality of slits extending in a circumferential direction at intervals in the circumferential direction and a plurality of bridge portions respectively positioned between the slits, at least some of the plurality of bridge portions are brittle bridge portions, and the cutout forming device Has an arcuate or circular outer blade with notches spaced along the bridge portion, the skirt wall of the container stopper rotates with respect to the outer blade, the outer blade acting radially inwardly of the skirt wall. Deformation of the face, wherein the breakage in the outer blade is easy Circumferential both sides of the cutout portion corresponding to the ridge portion, there is formed an inclined portion extending to both sides in the circumferential direction in an outwardly inclination of the radial direction.

In the cutout line of the metal container stopper of the present invention, the radial deformation amount between the upper and lower portions of the slit gradually decreases at least in the circumferential direction on both sides of the bridge portion which is easily broken. Therefore, the axial shear of the skirt wall is substantially absent or very weak, at least at the boundary between the breakable bridge and the slit, and the axial length of the breakable bridge is substantially zero or very small. As a result, the brittle bridge portion breaks horizontally and stably along the lower edge of the slit, ie the main portion of the skirt wall. Thus, no sharp residue is formed.

The tear line in the container closure of the present invention is formed by the tear line forming device of the present invention which provides an improvement in the shape of the notches formed along the bridge portion in the outer blade of the conventional tear line forming device. Such a perforation line forming apparatus is provided with an improvement in the shape of the notch in the outer blade of the conventional perforation line forming apparatus. Thus, a line of cut may be formed in the skirt wall of the container closure while increasing the manufacturing speed or reducing the manufacturing cost. The improvement provided in the shape of the notch in the outer blade, ie the formation of the circumferential bilateral portions of the notch to extend both sides in the circumferential direction in an inclined form, contributes to extending the life of the outer blade. With conventional outer blades, sharp edges are present on the outermost sides of both sides of the notch, which are often damaged. The above-described improvement of the shape of the notch in the outer blade does not form sharp edges, thus significantly reducing the risk of damaging the outer blade.

Preferred embodiments of the present invention are described in more detail below with reference to the accompanying drawings.

Referring to FIG. 1, the illustrated container closure 2, which may be formed of a suitable metal sheet such as an aluminum base alloy sheet, a chromated steel sheet or a tin plate, has a circular top panel wall 4 and the top panel wall 4. A cylindrical skirt wall 6 extending downward from the circumferential edge. It is present in the lower part of the skirt wall 6 of the annular projection 8 which protrudes somewhat in the radial direction. A perforation line 10 extending in the circumferential direction is formed in the annular projection 8. The perforation line 10 bisects the skirt wall 6 into a major portion 12 and an anti-theft base portion 14 positioned thereunder. The perforated line 10 itself consists of a plurality of slits 16 extending circumferentially at intervals in the circumferential direction and a plurality of bridge portions 18 and 20 respectively positioned between the slits 16. The plurality of bridge portions includes one difficult-to-break bridge portion 20 having a relatively large circumferential width, and all of the remaining bridge portions are easy-to-break bridge portions 18 except for the bridge portion 20, which is difficult to break. . The perforation line 10 is described in more detail below. The anti-theft base portion 14 of the skirt wall 6 has a score 22 extending axially from the circumferential end of the bridge portion 20, which is difficult to break the perforated line 10, to near the lower end of the anti-theft base portion 14. ) (Cut lines formed by reducing the thickness of the material) is formed. At the upper end of the main part of the skirt wall 6, slip preventing wrinkles 24 are formed. A sealing liner 28, which may be formed of a suitable plastic material, is disposed on the inner side of the top panel wall 4. The sealing liner 28 is generally circular, and an annular sealing portion 30 having two concentric sealing protrusions is formed in the circumferential wall edge portion.

The above-mentioned structure of the container closure 2 shown is already known and there is no new characteristic improvement according to the invention. Therefore, detailed description of this structure will be omitted.

2 shows the outer blade member 32 which the container closure 2 uses in the tear line forming device to form the score 22 along the tear line 10 in the skirt wall 6. At the upper end of the outer blade member 32 is formed an outer blade 34 extending in an arc shape. This outer blade member 32 is mounted on the perforation line forming apparatus of the type described in the above-described Japanese Patent Publications 43-17920, 45-14396 and 47-9636. By the perforation device, the skirt wall 6 of the container closure 2 rotates along the outer blade 34 such that the outer blade 34 cooperates with the inner blade to cut the perforation 10 into the skirt wall 6. And score 22 is formed. By means of the perforation line forming device, the formation of the annular projection 8 on the skirt wall 6 of the container closure 2 is carried out by a suitable tool (not shown) prior to the formation of the perforation line 10 and the score 22. If necessary, formation of the perforated line 10 and the score 22 The formation of the annular convex portion 8 can be performed at the same time. The structural description of the perforation line forming device itself is in the above-mentioned publication and is omitted in the specification herein. Nine notches 36, 38 are formed in the outer blade 34 at intervals in the circumferential direction. These notches 36, 38 are arranged in correspondence with the bridge portions 18, 20 of the perforations 10 formed in the skirt wall 6 of the container closure 2. Eight notches 36 correspond to the bridge portion 18 that is easy to break, but correspond to one notch 38 and the bridge portion 20 that is difficult to break. Referring to FIG. 3 in conjunction with FIG. 2, each notch 36 in the conventional outer blade is rectangular, as shown by the dashed-dotted line in FIG. In the present invention, it is important that the inclined portion 40 extending both sides in the circumferential direction with the outward inclination in the radial direction is formed in the circumferential opposite side portions of the notch 36. The circumferential width of the notch 38 corresponding to the bridge portion 20 which is difficult to break is set to be considerably larger than the circumferential width of the notch 36 corresponding to the bridge portion 18 that is easily broken. As clearly shown in FIG. 4, an inclined portion 42 extending outward in the circumferential direction with an outward inclination in the radial direction is formed at one end of the notch 38 corresponding to the bridge portion 20 which is difficult to break. do. In the illustrated embodiment, the working area of the outer blade 34 acts on the skirt wall 6 of the container closure 2 so that one end of the bridge portion 20 which is difficult to break is inclined to the notch 38. Although formed by 42, the other end is formed on top of the outer blade 34. Therefore, the other end of the notch 38 is formed by the upstream end of the outer blade 34 in terms of action. Thus, an inclined portion 44 inclined outwardly downstream with respect to the radial direction is also formed at an upstream end of the outer blade 34. Inclination of each of the inclined portions 40, 42, 44 inclined with respect to the radial direction Is suitable for 30 to 60 degrees. If desired, so-called rounding treatments may be provided at both ends of the inclined portions 40, 42, 44 (inward and outward ends in the radial direction) to make the inclined portion smooth.

As shown in FIG. 4, the bending tool portion 46 and the score forming tool portion 48 are provided in the outer blade member 32 with respect to the notch 38 corresponding to the bridge portion 20 which is difficult to break. . The upper end of the bending tool portion 46 and the upper end of the score forming tool portion 48 are aligned with the upper end of the outer blade 34. The upper end of the bending tool portion 46 is formed with a protrusion 50 having a substantially semicircular cross section. The outer circumferential surface of the protrusion 50 is 0.25 The smaller degree is located radially inward of the outer circumferential surface of the outer blade 34. At the upstream end of the score forming tool portion 48 is formed a projection 52 extending in the longitudinal direction. The protrusion 52 is formed in the skirt wall 6 of the container closure 2 in an arcuate recessed depression 53 corresponding to the convex portion of the annular convex portion 8. The cross section of the protrusion 52 is almost an isosceles square. The protrusion 52 is 0.13 It protrudes radially beyond the outer circumferential surface of the outer blade 34 by a small length. If desired, the bending tool portion 46 and score forming tool portion 48 may be integrally formed with the outer blade member 32.

When rotated along the outer blade 44 of the skirt wall 6 of the container closure 2, the slit 16 is acted upon by the action of the outer blade 34 cooperating with the inner blade 54 as shown in FIG. ) Is formed in the skirt wall 6. In detail, the outer blade 34 acts on the bottom of the annular projection 8 of the skirt wall to deform the skirt wall 6 radially inward, thereby forming an annular projection to form the slit 16. A shearing action is imposed between the top and bottom of 8). As shown in FIG. 6, in the notch 36 of the outer blade 34, the outer blade 34 does not impose shear action on the annular projection 8 of the skirt wall 6, so that breakage An easy bridge 18 remains behind. As described above, the notches 36 are formed at both radial side surfaces. Therefore, as clearly shown in FIG. 9, the radially inward deformation amount under the formed slit 16 is progressive toward the breakable bridge portion 18 on both sides in the circumferential direction of the breakable bridge portion 18. Is reduced. At both ends of the breakable bridge portion 18, the radially inward deformation amount can be substantially zero. According to the conventional perforation line forming apparatus, the inclined portion 40 is not formed in the notch 36. Therefore, as clearly shown in FIG. 10, the portion under the slit 16 is deformed radially inward in a significant amount even at both ends of the brittle portion 18 which is easy to break. As a result, not only the slit 16 extending in the circumferential direction, but also the shear line 56 extending in the axial direction at both ends of the bridge portion 18 which are easily broken, and as a result, the bridge portion (which is easily broken) 18) has some axial length.

The notch 38 of the outer blade 34 is independent of the shearing action on the annular projection 8 of the skirt wall 6, so that the bridge 20, which is difficult to break, remains behind. In the outer blade 34 shown, the inclined portion 42 is formed at one end of the notch 38 as described above, and the inclined portion 44 is formed at the upstream end of the outer blade 34. Therefore, at both ends of the bridge portion 20 which are difficult to break, the radially inward deformation amount under the formed slit 16 is directed toward the bridge portion 20 which is difficult to break, as at both ends of the bridge portion 18 which are easily broken. Progressively reduced. As clearly shown in FIG. 7, the protruding portion 52 of the score forming tool portion 48 in the bridge portion 20 that is difficult to break acts on the skirt wall 6, so that the bridge portion 20 that is difficult to break A score 22 is formed extending axially downward from one end of the scud wall 6 to the lower end. In addition, as clearly shown in FIG. 8, the protrusion 50 of the bending tool portion 46 acts on the convex portion 8 of the skirt wall 6, thereby cutting the bridge portion 20 which is difficult to break. The lower portion of the bridge portion 20, which is difficult to break, to bend along 10) is slightly deformed radially inward.

FIG. 11 shows a state where the container closure 2 of FIG. 1 is applied to the neck of the container. The neck 58 of the container, which can form glass or a suitable plastic material, is almost cylindrical in shape. On the outer circumferential surface there is formed a male screw 60 and a coupling flange 62 positioned below the male screw 60. When the container closure 2 is fitted on the neck to seal the neck 58, the container closure 2 is placed on the neck 58 and the annular sealing portion 30 of the sealing liner 28 is necked. The outer surface of the top panel wall 4 of the container closure 2 is pressurized to be in close contact with the upper end of 58. If this condition is maintained, the female thread 64 is formed along the male thread 60 of the neck 58 and in the region below the main portion 12 of the skirt wall 6 of the container closure 2, in particular the annular groove portion 26. 1 degree). In addition, the lower end portion of the anti-theft base portion 14 is bent radially inward to engage the engagement flange 62 of the neck portion 58.

Upon opening the container, the container closure 2 is rotated in the opening direction, ie counterclockwise when viewed from above in FIG. This rotation causes the container closure to move up under the joint action of the male screw 62 and the female screw 64. On the other hand, the anti-theft base portion 14 is engaged with the engaging flange 62 at the lower end and is prevented from rising, thereby generating a significant sound force in the columnar extended cut line 10 as in the axial extension score 22. . Under such stress, the bridge portion 18 which is easily broken in the cutout line 10 is broken, and the score 22 is also broken. As a result, the anti-theft base portion 14 in the endless annular shape is cut open in the form of a belt having an end as shown in FIG. Thus, the entire container closure 2 is freely lifted and released from the neck 58 as it rotates, so that the neck 58 can be freely used.

In the improved container closure 2 according to the invention, there is substantially no shear line 56 (FIG. 10) extending axially on both sides of the brittle bridge 18, which is present. Even if it is, it is very short. Therefore, the brittle bridge 18 in the perforated line 10 breaks slit, ie along the lower edge of the main portion 12 of the skirt wall 6, stably and substantially horizontally. Thus, no serrated break residues protruding downward from the lower edge of the main portion 12 of the skirt wall 6.

If it is desired to temporarily reseal the container once opened using the container stopper 2, the anti-theft base portion 14 is pulled to break the bridge portion 20 which is difficult to be broken without being damaged. The anti-theft base portion 14 is then removed from the skirt wall 6 of the container closure 2. Thus, the container stopper 2 in which the anti-theft base portion 14 is removed is provided to the neck 58, and the female screw 64 of the container stopper 2 is screwed around the male thread 60 of the neck 58.

Even at both ends of the bridge portion 20 which are difficult to break, there is no axially extending shear line 56 (Fig. 10). If there are three shear lines, it is very short. Further, bending is performed on the bridge portion 20 which is difficult to break along the perforation line 10. Thus, breakage of the bridge portion 20 which is difficult to break occurs along the perforation line 10, ie along the lower edge of the main portion 12 of the skirt wall 6. This prevents the occurrence of downward protruding serrated break residuals at the lower edge of the main portion 12 of the skirt wall 6 upon breakage of the bridge portion 20 which is difficult to break.

EXAMPLE

28, as shown in FIG. Container Stopper with Outer Diameter of 0.23 It was made using an aluminum based alloy sheet having a thickness of. Sealing liners were formed by compression molding polyethylene material on the inner surface of the top panel wall of the container closure. The circumferential width of the bridge portion that is easily broken is 0.71 to 0.74 And the width of the bridge which is difficult to break is 2.95 It was. Slope of each slope in the outer blade provided on the perforation device Was 45 degrees. FIG. 13 is a micrograph (magnification: about 37 times) of an adjacent region of the bridge portion where the container lid is easily broken.

The container closure is fitted to the neck in the shape as shown in FIG. 11 with the polyethylene terephthalate container in the manner as described with reference to FIG. The breakable bridging portion and score in the tear line thus open the neck by breaking in the manner described with reference to FIGS. 11 and 12. 14 is a photomicrograph (magnification: about 37 times) of a bridge | bridging part adjacent to breakage part which is easy to damage. As clearly shown in FIG. 14, there were no serrated break residues projecting downward from the major lower edge of the skirt wall. In addition, the bridge portion, which was difficult to break, was broken by pulling the anti-theft base portion. The break occurred horizontally along the perforation line and proved that there were no serrated break residues protruding downward from the main lower edge of the skirt wall.

Comparative Example

For comparison, the container stopper was formed in the same shape as in the above embodiment, except that the inclined portion was not formed in the outer blank provided on the perforation apparatus and the notch was rectangular in shape. 15 is a micrograph (magnification: about 37 times) of an adjacent region of the bridge portion that is easily broken in the formed container stopper. As clearly shown in FIG. 15, an axially extending shear line was formed at both ends of the brittle bridge, and the length of the shear line was 0.30. It was.

In the same way as in the embodiment described above, the container closure was fitted to the neck of the container. Therefore, the bridge | bridging part which scored easily in a perforation line | wire and a score | damage were broken, and the neck part was opened. 16 is a micrograph (magnification: about 37 times) of an adjacent region of the bridge portion that is easily broken. As clearly shown in FIG. 16, the brittle bridge portion has a serrated shape, and serrated fracture residues protruding downward from the lower edge of the main portion of the skirt wall are generated.

The improved container closure according to the invention has been produced without reducing the production rate or steaming the production costs. Nevertheless, it has a notable effect in that the formation of an inadequate serrated fracture residue due to breakage of the brittle portion which is easy to break is completely prevented.

In addition, the tear line forming device of the present invention can produce the improved container closure with an outer blade.

Although the invention has been described in detail with reference to the preferred embodiments, the invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (10)

A top skirt wall and a cylindrical skirt wall extending downwardly from a circumferential edge of the top panel wall, the skirt wall having a circumferentially extended cutout disposed within the skirt wall, the cutout being circumferentially spaced in the circumferential direction. It consists of a plurality of extending slits and a plurality of bridge portions respectively positioned between the slits, each of the slits is formed by shearing the upper and lower slits in the form of radial deformation, at least some of the plurality of bridge portions are easy to break bridge portion A metal container stopper according to claim 1, wherein the radial deformation amount between the upper and lower portions of the slit gradually decreases in the circumferential direction on both sides of the easy breakage portion toward the bridge portion that is easily broken. The metal container cap according to claim 1, wherein the radial deformation amount between the upper and lower portions of the slit is zero at both end portions of the circumferential sides of the bridge portion that are easily broken. The closure of claim 1 or 2, wherein the slit is formed by pressing the lower part of the slit radially inward against the upper part of the slit simultaneously with the shearing. 2. The method of claim 1, wherein at least one of the plurality of bridge portions is a bridge portion that is difficult to break, and the radial deformation amount between the upper and lower portions of the slit gradually decreases circumferentially on both sides of the bridge portion that is difficult to break toward the bridge portion that is difficult to break. Metal container stopper characterized in that. 5. The metal container cap according to claim 4, wherein the radial deformation amount between the upper and lower portions of the slit is zero at both end portions of the circumferential sides of the bridge portion, which are difficult to break. The metal container stopper according to claim 4 or 5, wherein bending is applied to the bridge portion which is difficult to break along the cut line. A cylindrical cutout is formed in the cylindrical skirt wall of the metal container stopper with the top panel wall, the skirt wall extending downward from the circumferential edge of the top panel wall, and the circumferential cutout extends circumferentially at intervals in the circumferential direction. A plurality of slits and a plurality of bridge portions respectively positioned between the slits, at least some of the plurality of bridge portions being easy to break, and having a notch arranged at intervals corresponding to the bridge portions. A perforated line forming device having an arcuate or circular outer blade, wherein the skirt wall of the container stopper rotates about the outer blade, the outer blade radially deforming the working side of the skirt wall radially. On the circumferential sides of the notch corresponding to this easy bridge portion. A perforated line forming device, characterized in that an inclined portion extending both sides in the circumferential direction with an outward inclination in the radial direction is formed. 10. The circumferential edge of the notch of the outer blade of claim 7, wherein at least one of the bridge portions is a bridge portion that is difficult to break, and an inclined portion that extends in both sides with a radially outward inclination in the circumferential direction thereof. Cut line forming apparatus, characterized in that formed on the end. The cutting line forming apparatus according to claim 7 or 8, wherein the inclined portion of the notch is inclined at an inclination of 30 to 60 degrees with respect to the radial direction. 9. A perforated line forming apparatus according to claim 8, wherein a bending tool portion for providing bending along the perforation line is bent in the notch of the outer blade corresponding to the fragile bridge portion.