JP3106332B2 - Synthetic resin container lid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an outer peripheral surface of a mouth and a neck formed with a male thread and a plurality of ratchet claws formed below the male thread at circumferential intervals. The present invention relates to a synthetic resin container lid having a so-called tamper-evident (mischievous manifestation) characteristic applied to a container having a certain form.

[0002]

2. Description of the Related Art It is not uncommon for a container lid to be attached to the mouth and neck of a container containing food or the like to have tamper-evident characteristics, and various forms of tamper-evident characteristics are required. Has been proposed and put to practical use.

[0003] A typical example of a synthetic resin container lid having tamper-evident properties is the form disclosed in Japanese Patent Publication No. 62-18420. The container lid includes, in addition to a top wall and a skirt wall depending from the periphery of the top wall, a tamper-evident band connected to the skirt wall via a breakable connection. A female screw thread is formed on the inner peripheral surface of the skirt wall, and a plurality of locking pieces are formed on the inner peripheral surface of the tamper evidence band at intervals in the circumferential direction. The breakable connection is
It is composed of a plurality of slits extending in the circumferential direction at intervals in the circumferential direction and a plurality of bridging portions remaining between these slits. Such a container lid is applied to a container in which an external thread and a locking jaw located below the external thread are formed on the outer peripheral surface of the mouth and neck. When the container lid is fitted to the mouth and neck of the container and rotated in the required closing direction, and the female thread of the container lid is sufficiently screwed into the male thread of the mouth and neck, the locking piece of the container lid is elastic. After being deformed and passing through the chin of the mouth and neck, it is elastically restored and locked to the lower surface of the chin. Further, the seal provided on the inner surface of the top wall of the container lid is brought into close contact with the mouth and neck, and the mouth and neck are sealed. When opening the mouth and neck of the container, the container cover is rotated in the opening rotation direction to release the female thread from the male thread. At this time, the container lid is moved upward with the rotation, but the tamper-evidence band cannot move upward because the locking piece is locked on the chin, so that the bridge of the breakable connection portion is not moved. A force acting on the entangled portion in the opening rotation direction and upward is applied, and the bridge portion is broken. Thereafter, only the tamper-evident band is left on the mouth and neck, and the container lid is detached from the mouth and neck.

On the other hand, in Japanese Patent Publication No. Sho 50-50664, a plurality of ratchet pawls are formed on the outer peripheral surface of the mouth and neck portion together with a male screw thread at a circumferential interval below the male screw thread. There is disclosed a container lid made of a synthetic resin having tamper-evident properties, which is applied to a container having a certain form. The container lid includes, in addition to a top wall and a skirt wall depending from the periphery of the top wall, a tear band (tamper evidence band) connected to the skirt wall via a breakable connection. Female threads are formed on the inner peripheral surface of the skirt wall, and a plurality of ratchet claws are formed on the inner peripheral surface of the tear band at intervals in the circumferential direction. The breakable connection portion is formed by a plurality of slits extending in the circumferential direction at intervals in the circumferential direction and a plurality of bridge portions remaining between the slits. When the container lid is fitted to the mouth and neck of the container and rotated in the required closing direction, and the female thread of the container lid is screwed sufficiently to the male thread of the mouth and neck, it is arranged on the inner surface of the top wall of the container lid. The seal provided is brought into close contact with the mouth and neck to seal the mouth and neck. At this time, the tear band of the container lid and the ratchet claw formed thereon are elastically deformed, and the ratchet claw formed on the tear band passes over the ratchet claw formed on the mouth and neck of the container. To move in the circumferential direction. When opening the mouth and neck of the container, first, a part of the tear band is grasped and pulled in a required direction to break the breakable connection, and the tear band is detached from the skirt wall. Thereafter, the container lid is rotated in the opening rotation direction to release the female thread from the male thread, and the container lid is released from the mouth and neck.

[0005]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Publication No. Sho 6
It has been found that the container lid disclosed in Japanese Patent Application Laid-Open No. 2-18420 has the following problems to be solved. That is, from the state where the container lid is attached to the mouth and neck of the container as required and the mouth and neck is sealed as required, when the container lid is slightly rotated in the opening rotation direction, the top wall of the container lid becomes It is lifted by a minute to release the seal from the mouth and neck, but elastic stretching of the bridge at the breakable connection,
It is not unlikely that the bridging portion is maintained without being broken due to the elastic deformation of the locking piece in the tamper-evidence band or the like. When such a situation occurs, the rupturable connection of the container lid is maintained and the seller or the consumer is kept in spite of the fact that the seal of the mouth and neck is broken and the contents of the container are corroded. Will not indicate what happened.

In the container lid disclosed in Japanese Patent Publication No. 50664/1985, the ratchet pawl of the mouth and neck and the ratchet pawl of the tear band of the container lid cooperate with each other to rotate the container lid instead of raising it. It is blocked itself. Therefore, it is virtually impossible to break the seal against the mouth and neck by rotating the container lid somewhat without breaking the rupturable connection and disengaging the tear band, as described above. Nothing happens. However, such a container lid has the following distinct problems. If there is so-called forced removal during mold release after injection molding or compression molding of the synthetic resin container lid, considerable stress acts on the bridging part of the breakable connection part, which causes There is a possibility that the entangled portion is broken. Thus, it is usually the case that the breakable connection, more particularly its bridge, is inclined downwardly radially outward or extends substantially horizontally radially outward (thus the breakable connection Inclined downward or radially outwardly and substantially horizontally outwardly, so that the inner diameter of the tear band is greater than the inner diameter of the breakable connection, and The diameter of the imaginary circle defined by the protruding end of the ratchet pawl formed on the inner peripheral surface of the tear band is made larger than the inner diameter of the rupturable connection part, thereby preventing the ratchet pawl from being forcibly released. doing. However, if such a configuration is adopted to avoid forcible removal, a downward force is applied to the top wall of the container lid when the container lid is attached to the mouth and neck of the container, and the lower end of the tear band of the container lid is applied. When an upward force is applied to the bridge, there is a possibility that the bridging portion of the breakable connection portion is excessively deformed and broken.

[0007] The present invention has been made in view of the above-mentioned facts, and a technical problem thereof is that the seal of the mouth and neck of the container is sufficiently damaged without breaking the breakable connection portion of the container lid. It is reliably avoided, and without forcible removal that adversely affects the breakable connection part at the time of release after molding, and therefore, without the risk of causing breakage of the breakable connection part at the time of release. It is an object of the present invention to provide an improved container lid which is molded and which does not have the risk of breaking the breakable connection, such as when attaching the container lid to the mouth and neck of the container.

[0008]

As a result of diligent research and experiment, the container lid disclosed in the above-mentioned Japanese Patent Publication No. Sho 50-50664 was improved to make the inner peripheral surface of the breakable connection substantially vertical. By extending the inner diameter of the tear band, the inner diameter of the tearable band is set to be larger than the inner diameter of the tearable band, and the diameter of the imaginary circle defined by the protruding end of the ratchet pawl formed on the inner peripheral surface of the tear band is reduced. It has been found that the above technical problem can be achieved by setting the inner diameter to be larger than the inner diameter.

That is, according to the present invention, as a container lid for achieving the above technical object, a top wall, a skirt wall hanging down from the periphery of the top wall, and a skirt wall connected to the skirt wall via a breakable connection portion. And a female thread is formed on the inner peripheral surface of the skirt wall, and a plurality of ratchet claws are formed on the inner peripheral surface of the tear band at circumferential intervals. In the synthetic resin container lid, the inner peripheral surface of the rupturable connection portion extends substantially vertically, and the outer peripheral surface of the rupturable connection portion is substantially vertically or radially outwardly inclined downward. Wherein the inner diameter of the tear band is greater than the inner diameter of the breakable connection, and the diameter of an imaginary circle defined by the protruding end of the ratchet pawl is greater than or equal to the inner diameter of the breakable connection. The synthetic resin container lid It is.

[0010] The rupturable connection portion exists continuously in the circumferential direction, and an outer peripheral surface of the rupturable connection portion extends downward and inclining in a radially outward direction. Preferably, a circumferential thin break line extending continuously in the direction is defined. Advantageously, the tear band is formed with an axial thin-wall fracture line extending in the axial direction, and a gripping protruding piece is formed adjacent to the axial thin-wall fracture line.

[0011]

In the container lid of the present invention, the tear band (tamper evidence band) has a plurality of ratchet pawls formed on the inner peripheral surface thereof. The rotation of the tear band itself is prevented by cooperation with the formed ratchet pawl, so that the container lid is rotated somewhat without breaking the rupturable connection and dislodging the tear band and sealing against the mouth and neck. It is virtually impossible to harm them. The inner diameter of the tear band is larger than the inner diameter of the breakable connection, and the diameter of the imaginary circle defined by the protruding end of the ratchet pawl is equal to or larger than the inner diameter of the breakable connection. It is possible to reliably avoid the occurrence of unreasonable influence that adversely affects the possible connection portion. In addition, when a downward force is applied to the top wall of the container lid when attaching the container lid to the mouth and neck of the container, and an upward force is applied to the lower end of the tear band of the container lid, the connection is rupturable. Because the inner peripheral surface of the portion extends substantially vertically following the lower end of the skirt wall, the forces acting on the breakable connection are directly transmitted to the skirt wall, and thus the breakable connection is There is no danger of being deformed and breaking.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a container lid constructed according to the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 and 2 illustrate a container lid, generally designated 2, which can be injection molded or compression molded from a suitable synthetic resin such as polypropylene or polyethylene. The container lid 2 includes a circular top wall 4 and a cylindrical skirt wall 6 hanging from the periphery of the top wall 4. The outer peripheral surface of the boundary region between the top wall 4 and the skirt wall 6 is formed in a truncated cone shape. On the inner surface of the top wall 4, two annular seal ridges, that is, an outer annular seal ridge 8 and an inner annular seal ridge 10 are integrally formed. If desired, a separately molded suitable form of sealing member can be applied to the inner surface of the top wall 4. A female thread 12 is formed on the inner peripheral surface of the skirt wall 6. Also, skirt wall 6
Is formed with an uneven shape 13 for preventing slip.

Continuing the description with reference to FIGS. 1 and 2,
A tear band 16 is connected to a lower end of the skirt wall 6 via a breakable connection portion 14. As clearly shown in FIG. 2, the inner peripheral surface 18 of the breakable connection 14 is substantially vertical (in other words substantially parallel to the central axis of the container lid 2) following the lower end of the skirt wall 6. On the other hand, the outer peripheral surface 20 of the breakable connection portion 14 is inclined downward and radially outwardly following the lower end of the skirt wall 6. Accordingly, the thickness of the breakable connection portion 14 is gradually increased from the upper side to the lower side, and a thin break line 22 extending continuously in the circumferential direction is defined at the upper end of the breakable connection portion 14. Conveniently, the thickness of the thin break line 22 is about 0.05 mm to 0.30 mm. The inner diameter of the rupturable connection 14 is larger than the inner diameter of the skirt wall 6, and the outer diameter of the upper end of the rupturable connection 14 is set substantially equal to the outer diameter of the skirt wall 16, and thus the upper end of the rupturable connection 14. The thickness is made smaller than the thickness of the lower end of the skirt wall 6. If desired, at least a portion of the outer peripheral surface 20 of the rupturable connection 14 can extend substantially vertically. As shown in FIG. 1, a slit 23 extending in the axial direction is formed in a specific portion in the circumferential direction of the breakable connection portion 14 (substantially the center portion in the left-right direction in FIG. 1).

The inner peripheral surface 24 and the outer peripheral surface 26 of the tear band 16 following the breakable connection 14 both extend substantially vertically, so that the thickness of the tear band 16 is substantially the same over the entire axial direction. . Referring to FIG. 3 together with FIG. 2, a plurality of (16 in the illustrated case) ratchet claws 28 are formed on the inner peripheral surface of the tearing band 16 at intervals in the circumferential direction. The front surface of each of the ratchet claws 28, which is located on the front side in the closing rotation direction indicated by the arrow 30, defines a gentle slope with respect to the inner peripheral surface 24 of the tearing band 16, and The rear surface located on the side defines an inclined surface that is steep with respect to the inner peripheral surface 24 of the tear band 16. The inner diameter of the tear band 16 is set to be larger than the inner diameter of the breakable connection portion 14,
The outer diameter of the tear band 16 is set to be substantially the same as the outer diameter of the lower end of the breakable connection portion 14. An imaginary circle 3 defined by the projecting or inner ends of a plurality of ratchet pawls 28 formed on the inner peripheral surface 24 of the tear band 16.
It is important that the diameter of 2 is greater than or equal to the inner diameter of rupturable connection 14 (in other words, substantially the same as or slightly larger than the inner diameter of rupturable connection 14). The tear band 16 is formed with a thin break line 34 extending in the axial direction so as to be axially aligned with the slit 23 formed in the breakable connection portion 14. Furthermore,
The outer peripheral surface 26 of the tear band 16 is integrally formed with a gripping protruding piece 36 that protrudes from a portion adjacent to the rear side when viewed in the closing rotation direction indicated by the arrow 30 with respect to the thin break line 34. The intermediate portion of the protruding piece 36 is connected to the outer peripheral surface 26 of the tear band 16 via a thin connecting column 38.

As described above, the inner diameter of the breakable connection portion 14 is set to be larger than the inner diameter of the skirt wall 6, and therefore, as clearly shown in FIGS. An annular shoulder surface 40 extending radially outward from the peripheral surface is formed. And this shoulder 40
Are formed with a plurality of recesses 42 at intervals in the circumferential direction. The concave portion 42 is formed for the sake of convenience in releasing after molding (this will be further described later), and does not relate to the function of the container lid 2 itself.

FIG. 4 shows the closed state of an injection mold for molding the container lid 2 together with the molded container lid 2. The injection mold generally designated by reference numeral 44 is composed of an upper mold part 46 and a lower mold part 48. The upper mold part 46 is integrally formed as a whole, and a molded concave portion 50 that defines the upper surface or the outer peripheral portion of the container lid 2 is formed on the lower surface thereof. The upper mold part 46 is further formed with an injection path 52 extending from the upper surface to the molding recess 50.
The lower mold portion 48 includes the outer member 54 and the ratchet pawl regulating member 5.
6, a female thread regulating member 58, a cylindrical inner member 60 and a columnar central member 62. The upper surface of the outer member 54 defines the lower surface of the tear band 16 in the container lid 2, and the outer peripheral surface of the upper end of the ratchet pawl regulating member 56 has the breakable connection portion 14 and the tear band 1 in the container lid 2.
6, the female thread regulating member 58 regulates the inner peripheral surface of the skirt wall 6 in the container lid 2, and the upper end of the cylindrical inner member 60 is outside the inner surface of the top wall 4 in the container lid 2. The upper edge of the cylindrical center member 62 regulates the inner peripheral center of the top wall 4 of the container lid 2. A cooling water circulation path 64 is formed in the cylindrical central member 62. After closing the injection mold 44 in the illustrated closed state, the synthetic resin material in a molten state is injected into the molding space through the injection path 52 of the upper mold part 46, and the container lid 2 is injection molded. After the molded container lid 2 is sufficiently cooled, the injection mold 44 is opened by an appropriate procedure and the container lid 2 is taken out. At this time, the outer member 54 of the lower mold portion 48, the ratchet pawl regulating member 56,
The cylindrical inner member 60 and the columnar center member 62 are moved downward. On the other hand, the female screw regulating member 58 of the lower mold part 48 is moved along the female screw 12 of the container lid 2 as shown in FIG.
Is rotated downward in a clockwise direction as viewed from above. At the upper end of the ratchet pawl regulating member 56,
Protrusions defining circumferentially spaced recesses 42 are formed in the shoulder surface 40 located on the lower surface of the skirt wall 6 of the container lid 2 at circumferentially spaced intervals, and are therefore internally threaded. The rotation of the container lid 2 accompanying the rotation of the regulating member 58 is prevented. Thus, not only the forcible removal that adversely affects the thin break line 22 in the breakable connection portion 14, that is, the forcible removal in the region below the thin break line 22 when viewed in the axial direction, but also in the region above the thin break line 22. Also, the molded container lid 2 can be released from the injection mold 44 without causing any forcible removal, and thus without causing inconvenience such as breaking the thin break line 22 of the breakable connection portion 14. it can.

Continuing with reference to FIG. 5, the container lid 2 as described above is applied to the mouth and neck 66 of a container that can be molded from glass or a suitable synthetic resin.
The mouth-and-neck portion 66 has a substantially cylindrical shape, and a male thread 68 is formed on the outer peripheral surface of the main portion. A relatively large-diameter overhang portion 70 is formed at the lower portion of the mouth and neck portion 66, and a plurality of ratchet claws 72 are formed on the outer peripheral surface of the overhang portion 70 at circumferential intervals. Have been. 5, when viewed from above in the counterclockwise direction (the direction opposite to the above-described closing rotation direction), the front surface of each ratchet pawl 72 located on the front side is gentle with respect to the outer peripheral surface of the overhang portion 70. A rear surface located on the rear side of each of the ratchet pawls 72 defines an inclined surface that is steep with respect to the overhang 70. An inner stopper 74, which can be molded from a suitable synthetic resin, is attached to the illustrated neck and neck 66. An inner plug 74, which is a well-known form in itself, has a substantially cylindrical main portion 76 having a trumpet-shaped spout formed at an upper end portion, and projects radially outward from a middle portion of the outer peripheral surface of the main portion 76. The flange portion 78 has a bottom portion 80 connected to a lower end of the main portion 76. A plurality of discharge openings 82 are formed in the bottom 80 and
A central projection 84 is formed on the upper surface of the central portion of the projection 0 so as to protrude upward.

The container lid 2 is fitted on the mouth and neck 66, and the container lid 2 is rotated in the closing rotation direction which is clockwise as viewed from above in FIG. When the screw is sufficiently screwed into the state shown in FIG. 5, the outer annular sealing ridge 8 of the container lid 2 is
8, the inner annular sealing ridge 10 is brought into close contact with the upper part of the inner peripheral surface of the main portion 76 of the inner plug 74, and thus the mouth and neck 66 is sealed. At the time of such a sealing operation, the ratchet pawl 72 formed on the overhang portion 70 of the mouth-and-neck portion 66 engages the inner peripheral surface 2 of the tear band 16 of the container lid 2.
4 interferes with the ratchet pawl 28 formed on the container cover 4, but the gentle front face of the ratchet pawl 28 and the gentle front face of the ratchet pawl 72 interact with each other, so that the container lid 2
The tear band 16 and the ratchet pawl 28 formed thereon are elastically deformed, whereby the ratchet pawl 28 moves over the ratchet pawl 72 in the circumferential direction. When the ratchet claw 28 gets over the ratchet claw 72, a force is transmitted from the tear band 16 to the breakable connection portion 14, but a force applied from below to the thin break line 22 which is the weakest portion of the breakable connection portion 14. Is transmitted to the lower end of the skirt wall 6 which is located above the axial direction, and the breakable connection portion 14 is supported by the lower end of the skirt wall 6. Therefore, the breakage of the thin break line 22 is sufficiently and reliably avoided. In the state illustrated in FIG. 5, even if the container lid 2 is rotated in the opening rotation direction, which is a counterclockwise direction when viewed from above, the ratchet claw 28 formed on the tearing band 16 of the container lid 2 has a raised rear surface. The cooperation of the ratchet pawl 72 formed on the overhang portion 70 of the mouth and neck portion 66 with the steep rear surface of the ratchet pawl 72 reliably prevents the rotation of the container lid 2. In this way, the seal of the mouth and neck 66 is reliably prevented from being damaged without the tear band 16 being torn.

When opening the mouth-and-neck portion 66 of the container, the gripping protruding piece 36 formed on the outer peripheral surface of the tear band 16 is gripped and pulled to break the connecting column 38 first, and then to tear. The thin break line 34 extending in the axial direction of the band 16 is broken, and thus the tear band 16 is opened with the breakable connection portion 14 into an end band.
Further, the protruding piece 36 is pulled in the counterclockwise direction as viewed from above in FIG. 5 to gradually break the thin break line 22 of the breakable connection portion 14 in the counterclockwise direction, and the breakable connection portion 14 and the tear band 16 are separated. Separate from the skirt wall 6. Thereafter, the remaining portion of the container lid 2, that is, the top wall 4
And the skirt wall 6 is rotated in the opening rotation direction so that the container lid 2
Of the female thread 12 of the mouth-and-neck part 66 and the container lid 2 is detached from the mouth-and-neck part 66.

In the above-described embodiment, the breakable connection portion 14 is continuous in the circumferential direction. However, if desired, a plurality of notches or slits are formed in the breakable connection portion 14 at intervals in the circumferential direction. You can also. In this case,
As shown in FIG. 6, a plurality of protrusions 86 (portions with crossing lines) may be provided on the outer peripheral surface of the upper end portion of the ratchet pawl regulating member 56 of the injection mold 44 at intervals in the circumferential direction. As can be understood by referring to FIG. 6, in this case as well, the molding is performed without causing any unreasonable pull-out, and hence without causing any inconvenience such as breaking the thin break line 22 of the breakable connection portion 14. Container lid 2
Can be released from the injection mold 44.

[0022]

The container lid made of synthetic resin of the present invention does not cause forcible withdrawal that adversely affects the breakable connection part at the time of mold release after molding, so that the breakable connection part is released at the time of mold release. It can be easily molded without breaking. When the container lid is attached to the mouth and neck of the container, the force applied to the breakable connection from below is transmitted to the lower end of the skirt wall, and the breakable connection is reliably prevented from being broken. When the container lid is attached to the mouth and neck of the container as required, the rotation of the container lid is directly prevented by the cooperation of the ratchet claw of the mouth and neck and the ratchet claw of the container lid,
Therefore, it is possible to reliably prevent the seal of the mouth and neck from being damaged without breaking the breakable connection portion.

[Brief description of the drawings]

FIG. 1 is a side view showing a preferred embodiment of a container lid constructed according to the present invention.

FIG. 2 is a sectional view of the container lid shown in FIG.

FIG. 3 is a bottom view of the container lid shown in FIG. 1;

FIG. 4 is a cross-sectional view showing the container lid shown in FIG. 1 together with a mold for molding the same.

FIG. 5 is a composite view showing a state in which the container lid shown in FIG. 1 is attached to the mouth and neck of the container, a part of which is a cross-sectional view and a part of which is a side view in which the container lid is cut away.

FIG. 6 is a partial cross-sectional view showing a modified example of the breakable connection portion together with a molding die for molding the same.

[Explanation of symbols]

 2: Container lid 4: Top wall 6: Skirt wall 12: Female thread 14: Breakable connection 16: Tear band 18: Inner circumferential surface of breakable connection 20: Outer circumference of breakable connection 22: Thin break Line 23: Slit 24: Inner peripheral surface of tear band 26: Outer peripheral surface of tear band 28: Ratchet claw 32: Virtual circle 34: Thin-wall fracture line 36: Projection piece for gripping 44: Mold 66: Container mouth and neck 68 : Male thread 72: Ratchet claw 74: Inner plug

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B65D 35/44-35/54 B65D 39/00-55/16

Claims (3)

(57) [Claims] 1. A top wall, a skirt wall hanging from a peripheral edge of the top wall, and a tear band connected to the skirt wall via a breakable connection portion, wherein an inner peripheral surface of the skirt wall is provided. Is a synthetic resin container lid in which a female thread is formed and a plurality of ratchet claws are formed on the inner peripheral surface of the tearing band at intervals in the circumferential direction. The circumferential surface extends substantially vertically, and the outer circumferential surface of the breakable connection extends substantially vertically or inclined radially outward downward, and the inner diameter of the tear band is the inner diameter of the breakable connection. A diameter of an imaginary circle defined by a protruding end of the ratchet claw is greater than or equal to an inner diameter of the breakable connection portion. 2. The rupturable connection part is continuously present in a circumferential direction, and an outer peripheral surface of the rupturable connection part extends downward and inclining radially outward, and an upper end of the rupturable connection part. The synthetic resin container lid according to claim 1, wherein a circumferential thin break line extending continuously in the circumferential direction is defined. 3. The tear band has an axial thin-wall fracture line extending in the axial direction, and a gripping protruding piece is formed adjacent to the axial thin-wall fracture line. 2. The synthetic resin container lid according to 2.