JP2020142836A - cap - Google Patents

Abstract

To provide a cap that can prevent blow-off and overrun.SOLUTION: A cap 1 attached to a container mouth part M so as to cover the container mouth part M, comprises a top wall 2 and a substantially tubular skirt wall 3 extending downward from an outer peripheral part of the top wall 2. The skirt wall 3 is provided with a female screw 5 screwed into a male screw M1 formed on an outer periphery of the container mouth portion M. In the skirt wall 3, a wall thickness of a lower part 14 located below the female screw 5 is made larger than the wall thickness of an upper part 15 located above the female screw 5.SELECTED DRAWING: Figure 2

Description

The present invention relates to, for example, a cap attached to the mouth of a container for containing contents such as beverages.

As shown in FIGS. 3A and 3B, the cap 51, which is detachably attached to the mouth portion M of the container by screw coupling and is configured to perform the closing and opening functions of the mouth portion M of the container, is Widely used in containers for various beverages (Patent Document 1).

Japanese Patent No. 5291175

By the way, in the conventional cap 51 attached to the container mouth portion M by screw coupling, the engagement range (area) of the female screw 52 of the cap 51 with the male screw M1 of the container mouth portion M becomes narrower with the opening operation. However, as long as the male screw M1 and the female screw 52 are engaged, the cap 51 will not come off from the container mouth portion M. However, for example, when a container is filled with a carbonated beverage, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, whereby the cap 51 is pushed up while the male screw M1 and the female screw 52 are engaged with each other. When the skirt wall 53 of the cap 51 is expanded to such an extent that it can overcome the male screw M1 and the engagement is disengaged, a phenomenon called blow-off occurs in which the cap pops off.

Further, with the above-mentioned conventional cap, when the cap is attached to the container mouth, if the cap is tightened too strongly, overrun (the female screw of the cap gets over the male screw of the container mouth) occurs and the cap is insufficiently closed. There is also a risk of becoming.

The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to provide a cap capable of preventing blow-off and overrun.

In order to achieve the above object, the cap according to the present invention is a cap attached to the container mouth so as to cover the container mouth, and is downward from the top wall and the outer peripheral portion of the top wall. It is provided with a substantially tubular skirt wall that extends, and the skirt wall is provided with a female screw that is screwed into a male screw formed on the outer periphery of the container mouth portion, and is located below the female screw in the skirt wall. The wall thickness of the portion was made larger than the wall thickness of the upper portion located above the female screw (claim 1).

Further, in the cap, in the region from the upper portion to the lower portion of the skirt wall, the wall thickness of the portion excluding the female screw may be increased toward the lower side (claim 2).

In the present invention, a cap capable of preventing blow-off and overrun can be obtained.

That is, in the cap of the present invention, since the wall thickness of the lower part is made larger than the wall thickness of the upper part, the skirt wall has only that much compared to the one in which the wall thickness of the lower part is equal to or less than the wall thickness of the upper part. It is difficult to expand and deform. Therefore, for example, when a sparkling beverage is filled in a container, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, so that the male screw at the mouth of the container and the female screw at the cap are engaged with each other. Even if a pushing force is applied to the cap as it is, it is difficult to expand the diameter of the skirt wall as described above, so that the diameter of the skirt wall is expanded to the extent that it can overcome the male screw, and the above engagement is prevented from being disengaged. It is possible to prevent the occurrence of blow-off.

Further, due to the difficulty of expanding the diameter of the skirt wall, it is possible to prevent the occurrence of overrun (the female screw of the cap gets over the male screw of the container mouth).

On the other hand, if the wall thickness of the portion excluding the female thread in the female thread forming region where the female thread is formed on the skirt wall is equal to or less than the wall thickness of the upper portion, the diameter is expanded in this female thread forming region, and blow-off and overrun are performed. However, in the cap of the invention according to claim 2, the female screw is removed in the region from the upper portion to the lower portion (the region including the female screw forming region) of the skirt wall. Since the wall thickness of the portion is increased toward the bottom, it is possible to sufficiently prevent the occurrence of blow-off and overrun.

(A) is a bottom view schematically showing a configuration of a cap according to an embodiment of the present invention, and (B) is a sectional view taken along line AA of (A). It is sectional drawing BB in FIG. 1 (A). (A) is a front view showing a conventional synthetic resin cap, and (B) is a front view showing a state in which the cap is attached to the container mouth.

Embodiments of the present invention will be described below with reference to the drawings.

The synthetic resin cap (hereinafter referred to as a cap) 1 shown in FIGS. 1A and 1B is a container having a male screw M1 and an annular protrusion (an example of an engaged portion) M2 as shown in FIG. 3B. It is used by being attached to a mouth portion M (for example, the mouth portion of a container such as a PET bottle) so as to cover it, and is integrally molded with polyethylene by compression molding or injection molding. The material for forming the cap 1 is not particularly limited, and polypropylene or the like is preferably used in addition to the polyethylene used in the present embodiment.

The cap 1 has a substantially circular top wall 2 in a plan view and a substantially cylindrical skirt wall 3 extending downward from the outer peripheral portion of the top wall 2 (see FIGS. 1A and 1B). Here, as shown in FIG. 1B, a knurled groove 4 is provided on the outer peripheral surface of the skirt wall 3, and a female screw 5 is provided on the inner peripheral surface, and the female screw 5 is formed on the outer periphery of the container mouth portion M. It can be coupled to the knurled M1.

Then, when the cap 1 is rotated and attached to the container mouth M so that the female screw 5 of the skirt wall 3 is connected to the male screw M1 of the container mouth M, the inner surface (lower surface) of the top wall 2 shown in FIG. 1 (B) is attached. The annular middle leg (inner ring) 6, the annular rib 7, and the annular outer leg (outer ring) 8 connected to the container mouth M are in close contact with each other, whereby the container mouth M is sealed. Become. That is, when the cap 1 is attached to the container mouth M, the middle leg 6 is inserted into the container mouth M and comes into close contact with the inner peripheral surface of the container mouth M, and the annular rib 7 is attached to the container mouth M. The outer leg 8 is configured to be in close contact with the upper end surface of the ring, and the outer leg 8 is in close contact with the outer peripheral surface of the container mouth portion M.

Further, the cap 1 is a pilfer-proof cap having a function of proving that it has not been opened (it has never been opened), and when the unopened cap 1 attached to the container opening M is opened (first). When the cap 1 is rotated so that the connection between the male screw M1 and the female screw 5 is released at the time of opening the cap 1, the cap 1 is separated from the container mouth M, but the tamper evidence is connected to the lower part of the skirt wall 3. The band (hereinafter, simply referred to as “band”) 9 (see FIG. 1 (B)) is configured to remain in the container mouth portion M.

That is, a band 9 is connected to the lower part of the skirt wall 3 via an annular weakening portion 10 extending over the entire circumference of the skirt wall 3 (see FIG. 1 (B)), and the annular weakening portion 10 is the skirt wall 3. A slit (perforated) extending intermittently in the circumferential direction of the skirt wall 3 and the band 9 and a bridge (bridge) existing between adjacent slits so as to draw the band 9 up and down. The bridge breaks when pulled by a given force.

Here, in this example, while the outer diameter of the band 9 is made uniform over the top and bottom, the band 9 is configured to project inward on the inner peripheral side and the amount of protrusion inward increases toward the upper side. Five hooks (an example of an engaging portion) 11 are provided at intervals (equal intervals in this example) in the circumferential direction (see FIGS. 1A and 1B). Each hook 11 is substantially below the annular protrusion M2 (see FIG. 3B) formed below the male screw M1 on the outer circumference of the container mouth M with the cap 1 attached to the container mouth M. It is located at and is locked to the annular protrusion M2 by the opening operation. That is, the hook 11 is configured to be able to be locked to the annular projection M2 from below. The two-dot chain line at the bottom of FIG. 2 shows the cross-sectional shape of the portion where the hook 11 is not provided.

Further, as shown in FIGS. 1B and 2, on the inner peripheral side of the band 9, the hook 11 protrudes inward from the inner surface of the upper end portion of the band 9, and the maximum protrusion amount thereof is the hook 11. A fitting portion 12 smaller than the maximum protrusion amount (inner diameter is larger than the inner diameter of the hook 11) is provided over the entire circumference of the band 9, and an inclined portion whose inner diameter becomes larger toward the upper side above the fitting portion 12. 13 are in a row.

Thus, in the unopened state attached to the container mouth portion M, the annular protrusion M2 is located inside the inclined portion 13 or above it, and when the cap 1 is rotated in the opening direction from this state, the container mouth portion The cap 1 rises relative to M, the fitting portion 12 is fitted to the annular protrusion M2, and the hook 11 is locked to the annular protrusion M2 from below. Further, when the cap 1 is continuously rotated in the opening direction, the annular weakening portion 10 is eventually broken and the band 9 remains in the container mouth portion M, while the cap body composed of the top wall 2 and the skirt wall 3 above the cap body is a container. It will be separated from the mouth M.

Therefore, the inclined portion 13 comes into contact with the annular projection M2 and the fitting portion 12 is further fitted to the outer peripheral surface of the annular projection M2 until the hook 11 is locked to the annular projection M2 from below. As a result, the band 9 is prevented from being lifted diagonally, and the annular weakened portion 10 is broken substantially uniformly without being biased, so that the tamper evidence property is good. Then, at the time of opening, the fitting portion 12 is fitted to the outer peripheral surface of the annular protrusion M2 of the container mouth portion M, and the hook 11 is surely engaged with the annular protrusion M2, so that the annular weakening portion 10 is broken. It is possible to prevent the so-called slip-out, in which the hook 11 gets over the annular protrusion M2.

Then, in this example, as shown in FIG. 2, in the skirt wall 3, the wall thickness of the lower portion 14 located below the female screw 5 (female screw forming region 5A) is reduced to that of the upper portion 15 located above the female screw 5. It is larger than the wall thickness.

Here, the lower portion 14 is a portion of the skirt wall 3 that is continuous below the female thread 5 (female thread forming region 5A). The inner peripheral surface of the lower portion 14 extends so as to be separated from the outer side (outer peripheral surface) toward the lower side. Further, the inner diameter of the lowermost portion 16 connected below the lower portion 14 increases toward the lower side, and the rate of change of the inner diameter in the vertical direction is larger than the rate of change of the inner diameter of the lower portion 14 in the vertical direction. ing.

On the other hand, the upper portion 15 is a portion of the skirt wall 3 that is continuous above the female thread 5 (female thread forming region 5A). The inner peripheral surface of the upper portion 15 also extends toward the lower side so as to be separated from the outer side (outer peripheral surface). Further, above the upper portion 15, a corner portion 17 extending so that the inner peripheral surface and the outer peripheral surface bend inward is connected.

Since the female screw 5 extends spirally on the inner peripheral surface of the skirt wall 3, the position and vertical width of the female screw 5 (female screw forming region 5A) are not uniform in the circumferential direction of the skirt wall 3. It will differ depending on the phase, and accordingly, the vertical widths of the lower portion 14 and the upper portion 15 will also differ depending on the phase.

As described above, in this example, since the wall thickness of the lower part 14 is made larger than the wall thickness of the upper part 15, the wall thickness of the lower part 14 is equal to or less than the wall thickness of the upper part 15. The skirt wall 3 is less likely to be expanded and deformed accordingly. Therefore, for example, when a container is filled with a carbonated beverage, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, whereby the male screw M1 and the female screw 5 remain engaged with each other in the cap 1. Even if a pushing force is applied, it is difficult to expand the diameter of the skirt wall 3 as described above. Therefore, it is prevented that the skirt wall 3 expands in diameter to the extent that it can overcome the male screw M1 and the engagement is disengaged. It is possible to prevent the occurrence of blow-off.

Further, due to the difficulty of expanding the diameter of the skirt wall 3, it is possible to prevent the occurrence of overrun (the female screw of the cap gets over the male screw of the container mouth portion).

On the other hand, if the wall thickness of the portion of the female screw forming region 5A excluding the female screw 5 is equal to or less than the wall thickness of the upper portion 15, the diameter is increased in the female screw forming region 5A to prevent blow-off and overrun. In this example, the wall thickness of the portion of the skirt wall 3 from the upper portion 15 to the lower portion 14 (the region including the female screw forming region 5A) excluding the female screw 5 is sufficient. Since it is made larger toward the bottom, it is possible to sufficiently prevent the occurrence of blow-off and overrun. The alternate long and short dash line shown in the upper part of FIG. 2 shows the cross-sectional shape of the portion of the skirt wall 3 excluding the female screw 5.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be variously modified and implemented without departing from the gist of the present invention. For example, the following modification examples can be given.

In the example of FIG. 2, from the upper end of the upper portion 15 to the lower end of the lower portion 14, the wall thickness of the portion excluding the female screw 5 is increased at a constant rate toward the lower side, but the thickness is not limited to this, for example. The ratio may be changed in the middle, or a portion where the wall thickness of the portion excluding the female screw 5 does not change may be provided in the vertical direction.

Further, a portion that does not correspond to either the lower portion 14 or the lowermost portion 16 may be provided between the lower portion 14 and the lowermost portion 16, or the lowermost portion 16 is not provided and the lower portion 14 is provided. May continue to the lower end of the skirt wall 3.

A portion that does not correspond to either the upper portion 15 or the corner portion 17 may be provided between the upper portion 15 and the corner portion 17.

Needless to say, the above-mentioned modifications may be combined as appropriate.

1 Cap 2 Top wall 3 Skirt wall 4 Knurled groove 5 Female thread 5A Female thread formation area 6 Middle foot 7 Ring rib 8 Outer foot 9 Tamper evidence band 10 Ring weakening part 11 Hook (engagement part)
12 Fitting part 13 Inclined part 14 Lower part 15 Upper part 16 Bottom part 17 Corner part 51 Cap 52 Female screw M Container mouth part M1 Male screw M2 Circular protrusion (engaged part)

The present invention relates to, for example, a cap attached to the mouth of a container for containing contents such as beverages.

As shown in FIGS. 3A and 3B, the cap 51, which is detachably attached to the mouth portion M of the container by screw coupling and is configured to perform the closing and opening functions of the mouth portion M of the container, is Widely used in containers for various beverages (Patent Document 1).

Japanese Patent No. 5291175

By the way, in the conventional cap 51 attached to the container mouth portion M by screw coupling, the engagement range (area) of the female screw 52 of the cap 51 with the male screw M1 of the container mouth portion M becomes narrower with the opening operation. However, as long as the male screw M1 and the female screw 52 are engaged, the cap 51 will not come off from the container mouth portion M. However, for example, when a container is filled with a carbonated beverage, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, whereby the cap 51 is pushed up while the male screw M1 and the female screw 52 are engaged with each other. When the skirt wall 53 of the cap 51 is expanded to such an extent that it can overcome the male screw M1 and the engagement is disengaged, a phenomenon called blow-off occurs in which the cap pops off.

Further, with the above-mentioned conventional cap, when the cap is attached to the container mouth, if the cap is tightened too strongly, overrun (the female screw of the cap gets over the male screw of the container mouth) occurs and the cap is insufficiently closed. There is also a risk of becoming.

The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to provide a cap capable of preventing blow-off and overrun.

In order to achieve the above object, the cap according to the present invention is a cap attached to the container mouth so as to cover the container mouth, and is downward from the top wall and the outer peripheral portion of the top wall. It is provided with a substantially tubular skirt wall that extends, and the outer portion of the corner portion formed by the top wall and the skirt wall is not recessed inward, and the skirt wall has an outer periphery of the container mouth portion. A female screw to be screwed into the male screw formed in the skirt wall is provided, and the wall thickness of the lower portion located below the female screw is made larger than the wall thickness of the upper portion located above the female screw in the skirt wall (claimed). Item 1).

Further, in the cap, in the region from the upper portion to the lower portion of the skirt wall, the wall thickness of the portion excluding the female screw may be increased toward the lower side (claim 2).
In the skirt wall, the inner peripheral surface of the lower portion extends so as to be separated from the outer peripheral surface toward the lower side, and the inner diameter of the lowermost portion connected below the lower portion increases toward the lower side. The rate of change of the inner diameter in the direction may be larger than the rate of change of the inner diameter of the lower portion in the vertical direction (claim 3).
Further, a tamper evidence band is connected to the lower part of the skirt wall via an annular weakening portion, and an annular protrusion formed below the male screw on the outer peripheral side of the container mouth portion on the inner peripheral side of the tamper evidence band. May be provided with an engaging portion configured to be lockable from below (claim 4).

In the present invention, a cap capable of preventing blow-off and overrun can be obtained.

That is, in the cap of the present invention, since the wall thickness of the lower part is made larger than the wall thickness of the upper part, the skirt wall has only that much compared to the one in which the wall thickness of the lower part is equal to or less than the wall thickness of the upper part. It is difficult to expand and deform. Therefore, for example, when a sparkling beverage is filled in a container, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, so that the male screw at the mouth of the container and the female screw at the cap are engaged with each other. Even if a pushing force is applied to the cap as it is, it is difficult to expand the diameter of the skirt wall as described above, so that the diameter of the skirt wall is expanded to the extent that it can overcome the male screw, and the above engagement is prevented from being disengaged. It is possible to prevent the occurrence of blow-off.

Further, due to the difficulty of expanding the diameter of the skirt wall, it is possible to prevent the occurrence of overrun (the female screw of the cap gets over the male screw of the container mouth).

On the other hand, if the wall thickness of the portion excluding the female thread in the female thread forming region where the female thread is formed on the skirt wall is equal to or less than the wall thickness of the upper portion, the diameter is expanded in this female thread forming region, and blow-off and overrun are performed. However, in the cap of the invention according to claim 2, the female screw is removed in the region from the upper portion to the lower portion (the region including the female screw forming region) of the skirt wall. Since the wall thickness of the portion is increased toward the bottom, it is possible to sufficiently prevent the occurrence of blow-off and overrun.

(A) is a bottom view schematically showing a configuration of a cap according to an embodiment of the present invention, and (B) is a sectional view taken along line AA of (A). It is sectional drawing BB in FIG. 1 (A). (A) is a front view showing a conventional synthetic resin cap, and (B) is a front view showing a state in which the cap is attached to the container mouth.

Embodiments of the present invention will be described below with reference to the drawings.

The synthetic resin cap (hereinafter referred to as a cap) 1 shown in FIGS. 1A and 1B is a container having a male screw M1 and an annular protrusion (an example of an engaged portion) M2 as shown in FIG. 3B. It is used by being attached to a mouth portion M (for example, the mouth portion of a container such as a PET bottle) so as to cover it, and is integrally molded with polyethylene by compression molding or injection molding. The material for forming the cap 1 is not particularly limited, and polypropylene or the like is preferably used in addition to the polyethylene used in the present embodiment.

The cap 1 has a substantially circular top wall 2 in a plan view and a substantially cylindrical skirt wall 3 extending downward from the outer peripheral portion of the top wall 2 (see FIGS. 1A and 1B). Here, as shown in FIG. 1B, a knurled groove 4 is provided on the outer peripheral surface of the skirt wall 3, and a female screw 5 is provided on the inner peripheral surface, and the female screw 5 is formed on the outer periphery of the container mouth portion M. It can be coupled to the knurled M1.

Then, when the cap 1 is rotated and attached to the container mouth M so that the female screw 5 of the skirt wall 3 is connected to the male screw M1 of the container mouth M, the inner surface (lower surface) of the top wall 2 shown in FIG. 1 (B) is attached. The annular middle leg (inner ring) 6, the annular rib 7, and the annular outer leg (outer ring) 8 connected to the container mouth M are in close contact with each other, whereby the container mouth M is sealed. Become. That is, when the cap 1 is attached to the container mouth M, the middle leg 6 is inserted into the container mouth M and comes into close contact with the inner peripheral surface of the container mouth M, and the annular rib 7 is attached to the container mouth M. The outer leg 8 is configured to be in close contact with the upper end surface of the ring, and the outer leg 8 is in close contact with the outer peripheral surface of the container mouth portion M.

Further, the cap 1 is a pilfer-proof cap having a function of proving that it has not been opened (it has never been opened), and when the unopened cap 1 attached to the container opening M is opened (first). When the cap 1 is rotated so that the connection between the male screw M1 and the female screw 5 is released at the time of opening the cap 1, the cap 1 is separated from the container mouth M, but the tamper evidence is connected to the lower part of the skirt wall 3. The band (hereinafter, simply referred to as “band”) 9 (see FIG. 1 (B)) is configured to remain in the container mouth portion M.

That is, a band 9 is connected to the lower part of the skirt wall 3 via an annular weakening portion 10 extending over the entire circumference of the skirt wall 3 (see FIG. 1 (B)), and the annular weakening portion 10 is the skirt wall 3. A slit (perforated) extending intermittently in the circumferential direction of the skirt wall 3 and the band 9 and a bridge (bridge) existing between adjacent slits so as to draw the band 9 up and down. The bridge breaks when pulled by a given force.

Here, in this example, while the outer diameter of the band 9 is made uniform over the top and bottom, the band 9 is configured to project inward on the inner peripheral side and the amount of protrusion inward increases toward the upper side. Five hooks (an example of an engaging portion) 11 are provided at intervals (equal intervals in this example) in the circumferential direction (see FIGS. 1A and 1B). Each hook 11 is substantially below the annular protrusion M2 (see FIG. 3B) formed below the male screw M1 on the outer circumference of the container mouth M with the cap 1 attached to the container mouth M. It is located at and is locked to the annular protrusion M2 by the opening operation. That is, the hook 11 is configured to be able to be locked to the annular projection M2 from below. The two-dot chain line at the bottom of FIG. 2 shows the cross-sectional shape of the portion where the hook 11 is not provided.

Further, as shown in FIGS. 1B and 2, on the inner peripheral side of the band 9, the hook 11 protrudes inward from the inner surface of the upper end portion of the band 9, and the maximum protrusion amount thereof is the hook 11. A fitting portion 12 smaller than the maximum protrusion amount (inner diameter is larger than the inner diameter of the hook 11) is provided over the entire circumference of the band 9, and an inclined portion whose inner diameter becomes larger toward the upper side above the fitting portion 12. 13 are in a row.

Thus, in the unopened state attached to the container mouth portion M, the annular protrusion M2 is located inside the inclined portion 13 or above it, and when the cap 1 is rotated in the opening direction from this state, the container mouth portion The cap 1 rises relative to M, the fitting portion 12 is fitted to the annular protrusion M2, and the hook 11 is locked to the annular protrusion M2 from below. Further, when the cap 1 is continuously rotated in the opening direction, the annular weakening portion 10 is eventually broken and the band 9 remains in the container mouth portion M, while the cap body composed of the top wall 2 and the skirt wall 3 above the cap body is a container. It will be separated from the mouth M.

Therefore, the inclined portion 13 comes into contact with the annular projection M2 and the fitting portion 12 is further fitted to the outer peripheral surface of the annular projection M2 until the hook 11 is locked to the annular projection M2 from below. As a result, the band 9 is prevented from being lifted diagonally, and the annular weakened portion 10 is broken substantially uniformly without being biased, so that the tamper evidence property is good. Then, at the time of opening, the fitting portion 12 is fitted to the outer peripheral surface of the annular protrusion M2 of the container mouth portion M, and the hook 11 is surely engaged with the annular protrusion M2, so that the annular weakening portion 10 is broken. It is possible to prevent the so-called slip-out, in which the hook 11 gets over the annular protrusion M2.

Then, in this example, as shown in FIG. 2, in the skirt wall 3, the wall thickness of the lower portion 14 located below the female screw 5 (female screw forming region 5A) is reduced to that of the upper portion 15 located above the female screw 5. It is larger than the wall thickness.

Here, the lower portion 14 is a portion of the skirt wall 3 that is continuous below the female thread 5 (female thread forming region 5A). The inner peripheral surface of the lower portion 14 extends so as to be separated from the outer side (outer peripheral surface) toward the lower side. Further, the inner diameter of the lowermost portion 16 connected below the lower portion 14 increases toward the lower side, and the rate of change of the inner diameter in the vertical direction is larger than the rate of change of the inner diameter of the lower portion 14 in the vertical direction. ing.

On the other hand, the upper portion 15 is a portion of the skirt wall 3 that is continuous above the female thread 5 (female thread forming region 5A). The inner peripheral surface of the upper portion 15 also extends toward the lower side so as to be separated from the outer side (outer peripheral surface). Further, above the upper portion 15, a corner portion 17 extending so that the inner peripheral surface and the outer peripheral surface bend inward is connected.

Since the female screw 5 extends spirally on the inner peripheral surface of the skirt wall 3, the position and vertical width of the female screw 5 (female screw forming region 5A) are not uniform in the circumferential direction of the skirt wall 3. It will differ depending on the phase, and accordingly, the vertical widths of the lower portion 14 and the upper portion 15 will also differ depending on the phase.

As described above, in this example, since the wall thickness of the lower part 14 is made larger than the wall thickness of the upper part 15, the wall thickness of the lower part 14 is equal to or less than the wall thickness of the upper part 15. The skirt wall 3 is less likely to be expanded and deformed accordingly. Therefore, for example, when a container is filled with a carbonated beverage, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, whereby the male screw M1 and the female screw 5 remain engaged with each other in the cap 1. Even if a pushing force is applied, it is difficult to expand the diameter of the skirt wall 3 as described above. Therefore, it is prevented that the skirt wall 3 expands in diameter to the extent that it can overcome the male screw M1 and the engagement is disengaged. It is possible to prevent the occurrence of blow-off.

Further, due to the difficulty of expanding the diameter of the skirt wall 3, it is possible to prevent the occurrence of overrun (the female screw of the cap gets over the male screw of the container mouth portion).

On the other hand, if the wall thickness of the portion of the female screw forming region 5A excluding the female screw 5 is equal to or less than the wall thickness of the upper portion 15, the diameter is increased in the female screw forming region 5A to prevent blow-off and overrun. In this example, the wall thickness of the portion of the skirt wall 3 from the upper portion 15 to the lower portion 14 (the region including the female screw forming region 5A) excluding the female screw 5 is sufficient. Since it is made larger toward the bottom, it is possible to sufficiently prevent the occurrence of blow-off and overrun. The alternate long and short dash line shown in the upper part of FIG. 2 shows the cross-sectional shape of the portion of the skirt wall 3 excluding the female screw 5.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be variously modified and implemented without departing from the gist of the present invention. For example, the following modification examples can be given.

In the example of FIG. 2, from the upper end of the upper portion 15 to the lower end of the lower portion 14, the wall thickness of the portion excluding the female screw 5 is increased at a constant rate toward the lower side, but the thickness is not limited to this, for example. The ratio may be changed in the middle, or a portion where the wall thickness of the portion excluding the female screw 5 does not change may be provided in the vertical direction.

Further, a portion that does not correspond to either the lower portion 14 or the lowermost portion 16 may be provided between the lower portion 14 and the lowermost portion 16, or the lowermost portion 16 is not provided and the lower portion 14 is provided. May continue to the lower end of the skirt wall 3.

A portion that does not correspond to either the upper portion 15 or the corner portion 17 may be provided between the upper portion 15 and the corner portion 17.

Needless to say, the above-mentioned modifications may be combined as appropriate.

1 Cap 2 Top wall 3 Skirt wall 4 Knurled groove 5 Female thread 5A Female thread formation area 6 Middle foot 7 Ring rib 8 Outer foot 9 Tamper evidence band 10 Ring weakening part 11 Hook (engagement part)
12 Fitting part 13 Inclined part 14 Lower part 15 Upper part 16 Bottom part 17 Corner part 51 Cap 52 Female screw M Container mouth part M1 Male screw M2 Circular protrusion (engaged part)

The present invention relates to, for example, a cap attached to the mouth of a container for containing contents such as beverages.

As shown in FIGS. 3A and 3B, the cap 51, which is detachably attached to the mouth portion M of the container by screw coupling and is configured to perform the closing and opening functions of the mouth portion M of the container, is Widely used in containers for various beverages (Patent Document 1).

Japanese Patent No. 5291175

By the way, in the conventional cap 51 attached to the container mouth portion M by screw coupling, the engagement range (area) of the female screw 52 of the cap 51 with the male screw M1 of the container mouth portion M becomes narrower with the opening operation. However, as long as the male screw M1 and the female screw 52 are engaged, the cap 51 will not come off from the container mouth portion M. However, for example, when a container is filled with a carbonated beverage, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, whereby the cap 51 is pushed up while the male screw M1 and the female screw 52 are engaged with each other. When the skirt wall 53 of the cap 51 is expanded to such an extent that it can overcome the male screw M1 and the engagement is disengaged, a phenomenon called blow-off occurs in which the cap pops off.

Further, with the above-mentioned conventional cap, when the cap is attached to the container mouth, if the cap is tightened too strongly, overrun (the female screw of the cap gets over the male screw of the container mouth) occurs and the cap is insufficiently closed. There is also a risk of becoming.

The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to provide a cap capable of preventing blow-off and overrun.

In order to achieve the above object, the cap according to the present invention is a cap that is attached to the container mouth so as to cover the container mouth, and is downward from the top wall and the outer peripheral portion of the top wall. It is provided with a substantially tubular skirt wall that extends, and the outer portion of the corner portion formed by the top wall and the skirt wall is not recessed inward, and the skirt wall has an outer periphery of the container mouth portion. screwed internal thread is provided on the male thread which is formed, in the skirt wall, the thickness of the lower portion located below the female screw, larger than the thickness of the upper part located above the internal thread, wherein In the skirt wall, the inner peripheral surface of the lower portion extends so as to be separated from the outer peripheral surface toward the lower side, and the inner diameter of the lowermost portion connected below the lower portion expands toward the lower side in the vertical direction. The rate of change of the inner diameter in the above portion is larger than the rate of change of the inner diameter in the vertical direction of the lower portion (claim 1).

Further, in the cap, in the region from the upper portion to the lower portion of the skirt wall, the wall thickness of the portion excluding the female screw may be increased toward the lower side (claim 2) .
Also, the tamper evidence band via an annular weakening is connected to a lower portion of the skirt wall, said on the inner peripheral side of the tamper evidence band, annular formed below the external thread in the outer periphery of the container mouth part An engaging portion configured to be locked from below may be provided on the protrusion (claim 3 ).

In the present invention, a cap capable of preventing blow-off and overrun can be obtained.

That is, in the cap of the present invention, since the wall thickness of the lower part is made larger than the wall thickness of the upper part, the skirt wall has only that much compared to the one in which the wall thickness of the lower part is equal to or less than the wall thickness of the upper part. It is difficult to expand and deform. Therefore, for example, when a sparkling beverage is filled in a container, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, so that the male screw at the mouth of the container and the female screw at the cap are engaged with each other. Even if a pushing force is applied to the cap as it is, it is difficult to expand the diameter of the skirt wall as described above, so that the diameter of the skirt wall is expanded to the extent that it can overcome the male screw, and the above engagement is prevented from being disengaged. It is possible to prevent the occurrence of blow-off.

Further, due to the difficulty of expanding the diameter of the skirt wall, it is possible to prevent the occurrence of overrun (the female screw of the cap gets over the male screw of the container mouth).

On the other hand, if the wall thickness of the portion excluding the female thread in the female thread forming region where the female thread is formed on the skirt wall is equal to or less than the wall thickness of the upper portion, the diameter is expanded in this female thread forming region, and blow-off and overrun are performed. However, in the cap of the invention according to claim 2, the female screw is removed in the region from the upper portion to the lower portion (the region including the female screw forming region) of the skirt wall. Since the wall thickness of the portion is increased toward the bottom, it is possible to sufficiently prevent the occurrence of blow-off and overrun.

(A) is a bottom view schematically showing a configuration of a cap according to an embodiment of the present invention, and (B) is a sectional view taken along line AA of (A). It is sectional drawing BB in FIG. 1 (A). (A) is a front view showing a conventional synthetic resin cap, and (B) is a front view showing a state in which the cap is attached to the container mouth.

Embodiments of the present invention will be described below with reference to the drawings.

The synthetic resin cap (hereinafter referred to as a cap) 1 shown in FIGS. 1A and 1B is a container having a male screw M1 and an annular protrusion (an example of an engaged portion) M2 as shown in FIG. 3B. It is used by being attached to a mouth portion M (for example, the mouth portion of a container such as a PET bottle) so as to cover it, and is integrally molded with polyethylene by compression molding or injection molding. The material for forming the cap 1 is not particularly limited, and polypropylene or the like is preferably used in addition to the polyethylene used in the present embodiment.

The cap 1 has a substantially circular top wall 2 in a plan view and a substantially cylindrical skirt wall 3 extending downward from the outer peripheral portion of the top wall 2 (see FIGS. 1A and 1B). Here, as shown in FIG. 1B, a knurled groove 4 is provided on the outer peripheral surface of the skirt wall 3, and a female screw 5 is provided on the inner peripheral surface, and the female screw 5 is formed on the outer periphery of the container mouth portion M. It can be coupled to the knurled M1.

Then, when the cap 1 is rotated and attached to the container mouth M so that the female screw 5 of the skirt wall 3 is connected to the male screw M1 of the container mouth M, the inner surface (lower surface) of the top wall 2 shown in FIG. 1 (B) is attached. The annular middle leg (inner ring) 6, the annular rib 7, and the annular outer leg (outer ring) 8 connected to the container mouth M are in close contact with each other, whereby the container mouth M is sealed. Become. That is, when the cap 1 is attached to the container mouth M, the middle leg 6 is inserted into the container mouth M and comes into close contact with the inner peripheral surface of the container mouth M, and the annular rib 7 is attached to the container mouth M. The outer leg 8 is configured to be in close contact with the upper end surface of the ring, and the outer leg 8 is in close contact with the outer peripheral surface of the container mouth portion M.

Further, the cap 1 is a pilfer-proof cap having a function of proving that it has not been opened (it has never been opened), and when the unopened cap 1 attached to the container opening M is opened (first). When the cap 1 is rotated so that the connection between the male screw M1 and the female screw 5 is released at the time of opening the cap 1, the cap 1 is separated from the container mouth M, but the tamper evidence is connected to the lower part of the skirt wall 3. The band (hereinafter, simply referred to as “band”) 9 (see FIG. 1 (B)) is configured to remain in the container mouth portion M.

That is, a band 9 is connected to the lower part of the skirt wall 3 via an annular weakening portion 10 extending over the entire circumference of the skirt wall 3 (see FIG. 1 (B)), and the annular weakening portion 10 is the skirt wall 3. A slit (perforated) extending intermittently in the circumferential direction of the skirt wall 3 and the band 9 and a bridge (bridge) existing between adjacent slits so as to draw the band 9 up and down. The bridge breaks when pulled by a given force.

Here, in this example, while the outer diameter of the band 9 is made uniform over the top and bottom, the band 9 is configured to project inward on the inner peripheral side and the amount of protrusion inward increases toward the upper side. Five hooks (an example of an engaging portion) 11 are provided at intervals (equal intervals in this example) in the circumferential direction (see FIGS. 1A and 1B). Each hook 11 is substantially below the annular protrusion M2 (see FIG. 3B) formed below the male screw M1 on the outer circumference of the container mouth M with the cap 1 attached to the container mouth M. It is located at and is locked to the annular protrusion M2 by the opening operation. That is, the hook 11 is configured to be able to be locked to the annular projection M2 from below. The two-dot chain line at the bottom of FIG. 2 shows the cross-sectional shape of the portion where the hook 11 is not provided.

Further, as shown in FIGS. 1B and 2, on the inner peripheral side of the band 9, the hook 11 protrudes inward from the inner surface of the upper end portion of the band 9, and the maximum protrusion amount thereof is the hook 11. A fitting portion 12 smaller than the maximum protrusion amount (inner diameter is larger than the inner diameter of the hook 11) is provided over the entire circumference of the band 9, and an inclined portion whose inner diameter becomes larger toward the upper side above the fitting portion 12. 13 are in a row.

Thus, in the unopened state attached to the container mouth portion M, the annular protrusion M2 is located inside the inclined portion 13 or above it, and when the cap 1 is rotated in the opening direction from this state, the container mouth portion The cap 1 rises relative to M, the fitting portion 12 is fitted to the annular protrusion M2, and the hook 11 is locked to the annular protrusion M2 from below. Further, when the cap 1 is continuously rotated in the opening direction, the annular weakening portion 10 is eventually broken and the band 9 remains in the container mouth portion M, while the cap body composed of the top wall 2 and the skirt wall 3 above the cap body is a container. It will be separated from the mouth M.

Therefore, the inclined portion 13 comes into contact with the annular projection M2 and the fitting portion 12 is further fitted to the outer peripheral surface of the annular projection M2 until the hook 11 is locked to the annular projection M2 from below. As a result, the band 9 is prevented from being lifted diagonally, and the annular weakened portion 10 is broken substantially uniformly without being biased, so that the tamper evidence property is good. Then, at the time of opening, the fitting portion 12 is fitted to the outer peripheral surface of the annular protrusion M2 of the container mouth portion M, and the hook 11 is surely engaged with the annular protrusion M2, so that the annular weakening portion 10 is broken. It is possible to prevent the so-called slip-out, in which the hook 11 gets over the annular protrusion M2.

Then, in this example, as shown in FIG. 2, in the skirt wall 3, the wall thickness of the lower portion 14 located below the female screw 5 (female screw forming region 5A) is reduced to that of the upper portion 15 located above the female screw 5. It is larger than the wall thickness.

Here, the lower portion 14 is a portion of the skirt wall 3 that is continuous below the female thread 5 (female thread forming region 5A). The inner peripheral surface of the lower portion 14 extends so as to be separated from the outer side (outer peripheral surface) toward the lower side. Further, the inner diameter of the lowermost portion 16 connected below the lower portion 14 increases toward the lower side, and the rate of change of the inner diameter in the vertical direction is larger than the rate of change of the inner diameter of the lower portion 14 in the vertical direction. ing.

On the other hand, the upper portion 15 is a portion of the skirt wall 3 that is continuous above the female thread 5 (female thread forming region 5A). The inner peripheral surface of the upper portion 15 also extends toward the lower side so as to be separated from the outer side (outer peripheral surface). Further, above the upper portion 15, a corner portion 17 extending so that the inner peripheral surface and the outer peripheral surface bend inward is connected.

Since the female screw 5 extends spirally on the inner peripheral surface of the skirt wall 3, the position and vertical width of the female screw 5 (female screw forming region 5A) are not uniform in the circumferential direction of the skirt wall 3. It will differ depending on the phase, and accordingly, the vertical widths of the lower portion 14 and the upper portion 15 will also differ depending on the phase.

As described above, in this example, since the wall thickness of the lower part 14 is made larger than the wall thickness of the upper part 15, the wall thickness of the lower part 14 is equal to or less than the wall thickness of the upper part 15. The skirt wall 3 is less likely to be expanded and deformed accordingly. Therefore, for example, when a container is filled with a carbonated beverage, the internal pressure of the container is increased by the gas pressure derived from carbon dioxide gas, whereby the male screw M1 and the female screw 5 remain engaged with each other in the cap 1. Even if a pushing force is applied, it is difficult to expand the diameter of the skirt wall 3 as described above. Therefore, it is prevented that the skirt wall 3 expands in diameter to the extent that it can overcome the male screw M1 and the engagement is disengaged. It is possible to prevent the occurrence of blow-off.

Further, due to the difficulty of expanding the diameter of the skirt wall 3, it is possible to prevent the occurrence of overrun (the female screw of the cap gets over the male screw of the container mouth portion).

On the other hand, if the wall thickness of the portion of the female screw forming region 5A excluding the female screw 5 is equal to or less than the wall thickness of the upper portion 15, the diameter is increased in the female screw forming region 5A to prevent blow-off and overrun. In this example, the wall thickness of the portion of the skirt wall 3 from the upper portion 15 to the lower portion 14 (the region including the female screw forming region 5A) excluding the female screw 5 is sufficient. Since it is made larger toward the bottom, it is possible to sufficiently prevent the occurrence of blow-off and overrun. The two-dot chain line shown in the upper part of FIG. 2 indicates the cross-sectional shape of the portion of the skirt wall 3 excluding the female screw 5.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be variously modified and implemented without departing from the gist of the present invention. For example, the following modification examples can be given.

In the example of FIG. 2, from the upper end of the upper portion 15 to the lower end of the lower portion 14, the wall thickness of the portion excluding the female screw 5 is increased at a constant rate toward the lower side, but the thickness is not limited to this, for example. The ratio may be changed in the middle, or a portion where the wall thickness of the portion excluding the female screw 5 does not change may be provided in the vertical direction.

Further, a portion that does not correspond to either the lower portion 14 or the lowermost portion 16 may be provided between the lower portion 14 and the lowermost portion 16, or the lowermost portion 16 is not provided and the lower portion 14 is provided. May continue to the lower end of the skirt wall 3.

A portion that does not correspond to either the upper portion 15 or the corner portion 17 may be provided between the upper portion 15 and the corner portion 17.

Needless to say, the above-mentioned modifications may be combined as appropriate.

1 Cap 2 Top wall 3 Skirt wall 4 Knurled groove 5 Female thread 5A Female thread formation area 6 Middle foot 7 Ring rib 8 Outer foot 9 Tamper evidence band 10 Ring weakening part 11 Hook (engagement part)
12 Fitting part 13 Inclined part 14 Lower part 15 Upper part 16 Bottom part 17 Corner part 51 Cap 52 Female screw M Container mouth part M1 Male screw M2 Circular protrusion (engaged part)

Claims (2)

A cap that is attached to the container mouth so as to cover the container mouth.
With the top wall
It is provided with a substantially tubular skirt wall extending downward from the outer peripheral portion of the top wall.
The skirt wall is provided with a female screw that is screwed into a male screw formed on the outer circumference of the container mouth.
A cap in which the wall thickness of the lower portion of the skirt wall located below the female screw is larger than the wall thickness of the upper portion located above the female screw. The cap according to claim 1, wherein the wall thickness of the portion of the skirt wall from the upper portion to the lower portion excluding the female screw is increased toward the lower side.