JP2017202862A - Synthetic resin-made container lid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely avoid occurrence of molding defect of plural locking protrusions arranged on the inner peripheral surface of a tamper-evident skirt part without increasing the amount of a synthetic resin material required for molding.SOLUTION: A synthetic resin-made container lid 2 comprises a cylindrical skirt wall 6 pending from the peripheral edge of a circular top surface wall 4, and a breaking line extending in a circumferential direction is formed on the skirt wall. The skirt wall is partitioned into a main part located above the circumferential breaking line and a lower tamper-evident skirt part. A female screw 30a is formed on the inner peripheral face of the main part of the skirt wall. Plural locking protrusions 32 extending in a circumferential direction at intervals are formed on the inner peripheral face of the tamper-evident skirt part, and each locking protrusion has a locking top face extending inside in a radial direction. The female screw is configured by plural female screw parts interrupted by plural interrupted regions at intervals in the circumferential direction. The container lid is configured so that the female screw part exists above at least circumferential middle part of the locking protrusion in an axial direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a synthetic resin container lid having tamper-evident characteristics, more specifically, a circular top wall and a cylindrical skirt wall depending from the periphery of the top wall. The skirt wall is partitioned into a main part above the circumferential break line and a tamper evidence skirt below the circumferential break line, and the inner peripheral surface of the main part of the skirt wall Is formed with a plurality of locking projections extending in the circumferential direction at intervals in the circumferential direction on the inner circumferential surface of the tamper evidence skirt. Each relates to a synthetic resin container lid having a locking upper surface extending radially inward.

  As a beverage container, it is made of an appropriate synthetic resin such as polyethylene terephthalate, glass or metal thin plate, and a male screw thread and a locking jaw part located below the male screw thread are formed on the outer peripheral surface of the cylindrical mouth and neck. Formed containers are widely used in practice. Then, as disclosed in Patent Documents 1 and 2 below, a synthetic resin container lid having the above-described configuration is adopted as a container lid to be attached to the mouth and neck of such a container. In such a container lid, the top wall and the skirt wall are well known to those skilled in the art in order to reduce the manufacturing cost by reducing the amount of synthetic resin material required for molding, and to reduce the weight. The internal thread formed on the inner peripheral surface of the main part of the skirt wall is interrupted by a plurality of interrupting regions arranged at intervals in the circumferential direction. It is constituted by a plurality of female thread portions.

JP 2011-143942 A Japanese Patent Laying-Open No. 2015-93704

  Thus, according to the experience of the present inventors, in the conventional container lid as described above, some of the plurality of locking projections arranged on the inner peripheral surface of the tamper evidence skirt portion. It has been found that there are many cases in which molding defects occur, that is, deformation does not occur because the molding is not accurately shaped as required. When opening the mouth and neck of the container, it is important that the locking protrusion is securely locked to the locking jaw of the mouth and neck. Therefore, if the locking protrusion is deformed, the opening and closing of the mouth and neck There is a risk that inconvenience may occur during the process.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is that a plurality of elements disposed on the inner peripheral surface of the tamper evidence skirt without increasing the amount of synthetic resin material required for molding. It is to avoid the molding defects in the individual locking projections with sufficient reliability.

  As a result of intensive studies, the present inventors have found that the above-described formation failure of the locking protrusion occurs in the locking protrusion located in the axial direction corresponding to the interrupted region of the female thread (the reason will be described later). I found out. And based on this knowledge, the main technique described above is configured such that there is a female thread portion rather than a suspended region of the female thread above the axial direction of at least the circumferential intermediate portion of the locking projection. We found that we can achieve the objective.

That is, according to the present invention, the synthetic resin container lid capable of achieving the main technical problem includes a circular top wall and a cylindrical skirt wall depending from the periphery of the top wall, and the skirt wall A rupture line extending in the circumferential direction is formed in the skirt wall, and the skirt wall is partitioned into a main portion above the rupture line and a tamper evidence skirt below the rupture line. A female thread is formed on the inner peripheral surface of the main portion, and a plurality of locking projections extending in the circumferential direction are arranged on the inner peripheral surface of the tamper evidence skirt at intervals in the circumferential direction. Each of the locking projections is a synthetic resin container lid having a locking upper surface extending radially inward,
The female thread is composed of a plurality of female thread parts interrupted by a plurality of interrupting regions arranged at intervals in the circumferential direction,
The female thread portion exists instead of the interrupted region of the female thread at least in the axially upper direction of the circumferential intermediate portion of the locking projection.
A synthetic resin container lid is provided.

  In a preferred embodiment, the radial extension length of the locking upper surface at the circumferential intermediate portion of the locking projection is the radial extension length of the locking upper surface at both circumferential sides of the locking projection. Bigger than that. The extending length in the radial direction of the locking upper surface in the circumferential intermediate portion of the locking projection is gradually reduced from the center in the circumferential direction toward both sides in the circumferential direction. The radially extending length of the locking upper surface is gradually reduced toward both sides in the circumferential direction, is zero at both circumferential ends, and the radial direction of the locking upper surface at both circumferential ends of the circumferential intermediate portion Conveniently, the extending length and the radially extending length of the locking upper surface at the circumferential inner ends of both sides in the circumferential direction are the same. Preferably, the N locking projections are arranged in odd numbers at equal intervals in the circumferential direction, and the circumferential lengths of the locking projections are the same, and the interruption of the female thread 2N regions are arranged at equal intervals in the circumferential direction, and the circumferential center of the locking projection is aligned with the circumferential center of the female thread portion in the axial direction. N is preferably 5.

  According to the synthetic resin container lid of the present invention, the female thread is constituted by a plurality of female thread portions interrupted by a plurality of interrupting regions arranged at intervals in the circumferential direction. Since there is a female threaded portion instead of an interrupted region of the female thread at the axially upper portion of at least the circumferential middle portion of the stop projection, the tamper evidence hem is increased without increasing the amount of synthetic resin material required for molding. A molding defect in the plurality of locking projections arranged on the inner peripheral surface of the part can be avoided sufficiently reliably.

The front view which shows a suitable embodiment of the synthetic resin container lid comprised according to this invention in part in a cross section. The bottom view of the container lid shown in FIG. The slope view which cuts and shows a part of container lid shown in FIG. The expanded view of the inner peripheral surface of the skirt wall in the container lid shown in FIG.

  Hereinafter, a preferred embodiment of a synthetic resin container lid constructed according to the present invention will be described in more detail with reference to the accompanying drawings.

  Referring to FIG. 1, a container lid 2 that can be injection-molded or compression-molded from a suitable synthetic resin such as polyethylene or polypropylene includes a circular top wall 4 and a cylindrical skirt depending from the periphery of the top wall 4. Wall 6. A relatively short cylindrical outer seal piece 10 that hangs downward is formed on the outer peripheral edge of the inner surface of the top wall 4 together with a relatively long cylindrical inner seal piece 8 that hangs downward. An annular protrusion 12 is formed between the inner seal piece 8 and the outer seal piece 10.

  A rupture line 14 extending in the circumferential direction is formed on the skirt wall 6, and the skirt wall 6 is partitioned into a main portion 16 above the break line 14 and a tamper evidence skirt 18 below the break line 14. . In the illustrated embodiment, the breaking line 14 is composed of a plurality of slits (grooves) 20 extending in the circumferential direction and a plurality of bridging portions 22 remaining between the slits 20. The dent skirt portion 18 is connected to the main portion 16 via a plurality of bridging portions 22.

  On the outer peripheral surface of the main portion 20 of the skirt wall 6, anti-slip knurls 24 are formed, which are configured by uneven shapes alternately present in the circumferential direction. 2 and FIG. 4 together with FIG. 1, a female thread 26 is formed on the inner peripheral surface of the main portion 16 of the skirt wall 6. In the illustrated embodiment, a single female thread 26 extending over about 720 degrees (two turns) is formed, and the lower female thread located on the lower side in the axial direction at any part in the circumferential direction. 26a and an upper female thread 26b located on the upper side in the axial direction. Each of the lower female thread 26a and the upper female thread 26b has a plurality of interrupting regions 28a and 28b (respectively later) arranged at intervals in the circumferential direction from the viewpoint of reducing the amount of synthetic resin material necessary for molding. If the number of the locking projections to be referred to is N, the number of the interrupting regions 28a and 28b is preferably an integer multiple of N, particularly 2N). It is important to be formed from. In the illustrated embodiment, in each of the lower female thread 26a and the upper female thread 26b, ten interruption regions 28a and 28 and ten female thread portions 30a and 30b are arranged at equal intervals. The circumferential lengths of the interrupted regions 28a and 28b are the same, and the circumferential lengths of the female thread portions 30a and 30b are also the same. Each of the interrupting regions 28a in the lower female thread 26a and each of the interrupting regions 28b in the upper female screw 26b are aligned in the axial direction. Therefore, each of the female screw parts 30a in the lower female screw 26a and the upper female Each of the female thread portions 30b in the thread 26b is aligned in the axial direction. A plurality of female threads can be formed instead of forming one female thread. Also in this case, the circumferential lengths of the interruption regions in each female thread are the same, the circumferential lengths of the female screw portions are also the same, each of the interruption regions in each female screw and the female screw portion. Each is preferably aligned in the axial direction.

  Continuing the description with reference to FIGS. 1 to 4, a plurality of locking projections 32, which are preferably spaced at an interval in the circumferential direction, are arranged on the inner peripheral surface of the tamper evidence skirt 18. It is installed. In the illustrated embodiment, five locking projections 32 are arranged at equal intervals in the circumferential direction, and each of the locking projections 32 is substantially the same, and circumferentially along with the circumferential intermediate portion 32a. It has both side parts 32b. As can be understood by referring to FIG. 2, a locking protrusion non-existing portion 34 in which the locking protrusion 32 does not exist on the opposite side in the diameter direction of each circumferential intermediate portion 32 a of the locking protrusion 32 (the locking protrusion). Each non-existing portion 34 is provided with an arc-shaped protrusion having a small protrusion amount). As clearly understood by referring to FIG. 4, it is important that the female thread portions 30a and 30b exist at least in the axial direction above the circumferential intermediate portion 32a of the locking projection 32 (the reason for this) Will be described later). In the illustrated embodiment, the inner circumferential end 32a of the locking protrusion 32 and the circumferential inner ends and outer ends of both circumferential ends 32b are also located below the female thread portions 30a and 30b in the axial direction.

  Each of the locking protrusions 32 extends radially inwardly, a locking upper surface 36 extending inward in the radial direction, a tip surface 38 having a substantially semicircular arc shape in a longitudinal sectional view, and extending downwardly in a radially outward direction. It has a guide lower surface 40. The protruding length in the radial direction of the locking upper surface 36 at the circumferential intermediate portion 32a is set to be larger than the protruding length in the radial direction of the locking upper surface 36 at both circumferential side portions 32b. More specifically, as clearly understood by referring to FIG. 2, in the illustrated embodiment, in the circumferential intermediate portion 32a, the radially extending length of the locking upper surface 36 faces both sides in the circumferential direction. The radial extension length of the locking upper surface 36 is gradually reduced toward both sides in the circumferential direction at both circumferential sides 32b, and is substantially zero at both circumferential ends. The radial extension length of the locking upper surface 36 at the circumferential inner ends of the circumferential side portions 32b is substantially the same as the radial extension length of the locking upper surface 36 at both circumferential ends of the circumferential central portion 32a. is there. In the illustrated embodiment, the lower edge of each guide lower surface 40 of the locking projection 32 extends substantially horizontally from the circumferential intermediate portion 32a to a portion of the circumferential side portions 32b (ie, the circumferential inner portion). The lower edge of the guide lower surface 40 is inclined upward in the axial direction toward the outer end in the circumferential direction at the outer circumferential portion of both side portions 32b in the circumferential direction.

  In the region where the locking protrusion 32 is present as viewed in the circumferential direction, the upper inner surface of the tamper evidence skirt 18 is slightly outward in the radial direction from the locking upper surface 36 of the locking protrusion 32 upward in the axial direction. The inclined inner surface 42 is inclined at an angle, in other words, the inner diameter is gradually increased upward in the axial direction. On the other hand, in the locking protrusion non-existing portion 34 where the locking protrusion 32 does not exist when viewed in the circumferential direction, the inner surface of the tamper evidence skirt 18 is not inclined and is flush with the portion above the inclined inner surface 42. There is no.

  Thus, as described above, in the conventional container lid, molding defects often occur in some of the plurality of locking projections formed on the inner peripheral surface of the tamper evidence skirt. It was. According to the study by the present inventors, the molding failure of the locking projection occurs in a region where the female thread portion does not exist when viewed in the circumferential direction, and in particular, the radial direction of the locking upper surface 36 of the locking projection 32. This occurred remarkably when the circumferential intermediate portion 32a, which is a portion having a large protruding length (a portion having a small inner diameter), coincides with a region where the female thread portion does not exist. However, in the container lid 2 constructed according to the present invention, the female thread portions 30a and 30b are present at least in the axial direction above the circumferential intermediate portion 32a of the locking projection 32, and hence the locking projection 32 is provided with the locking projection 32. Occurrence of molding defects is avoided as much as possible. The reason for this is that the present inventors need so-called forced removal in the female thread portions 30a and 30b and the locking projection 32 when taking out the molded container lid from the molding die. When the female threaded portions 30a and 30b exist above the circumferential intermediate portion 32a in the axial direction, the skirt wall 6 is radially outwardly directed downward due to excessive removal of the female threaded portions 30a and 30b. This is considered to be because the unreasonable removal of the locking protrusion 32 is alleviated. Incidentally, the female thread portions 30a and 30b have a relatively strong resistance against deformation or damage due to unreasonable due to their shapes, but the locking protrusion 32 is deformed due to unreasonable due to their shapes. Or relatively low resistance to damage.

  FIG. 1 also shows the mouth / neck portion 44 of the container together with the container lid 2. The mouth / neck portion 44 of a container that can be formed from an appropriate synthetic resin such as polyethylene terephthalate, glass, or a metal thin plate has a cylindrical shape as a whole, and the outer peripheral surface of the mouth / neck portion 44 is approximately 720 degrees (two rolls). There is one male thread 46 extending across, ie, a lower male thread 46a positioned on the lower side in the axial direction and an upper male thread 46b positioned on the upper side in the axial direction. Further, a locking jaw portion 48 is formed which is positioned below the lower male thread 46a. Further provided on the outer peripheral surface of the mouth / neck portion 44 is a support ring 50 located below the locking jaw portion 48 (the support ring 50 is used for transporting containers as is well known to those skilled in the art). ing.

  When the container lid 2 is attached to the mouth and neck portion 44 after the contents are filled in the container and the mouth and neck portion 44 is sealed, the container lid 2 is fitted on the mouth and neck portion 44 and the container lid 2 is closed. 1, the female thread 26 of the container lid 2 is screwed onto the male thread 46 of the mouth-and-neck portion 44. When the female thread 26 is screwed onto the male thread 46 until the state shown in FIG. 1, the inner seal piece 8 of the container lid 2 enters the mouth neck part 44 and is brought into close contact with the inner peripheral surface of the mouth neck part 44. The annular protrusion 12 is brought into close contact with the top surface of the mouth-and-neck portion 44, and the outer seal piece 10 is brought into intimate contact with or close to the outer peripheral surface of the mouth-and-neck portion 44, thus sealing the mouth-and-neck portion 44.

  When the container lid 2 is attached to the mouth / neck portion 44 and the mouth / neck portion 44 is sealed, the locking protrusion 32 disposed on the inner peripheral surface of the tamper-evidence hem portion 18 engages with the mouth / neck portion 44. The stopper jaw 48 is elastically moved over and is positioned below the locking jaw 48. At this time, the locking projection 32 is gradually displaced outward in the radial direction by the guiding action of the guide lower surface 40 of the locking projection 32 and smoothly moves over the locking jaw 48. The extending length of the locking upper surface 36 inward in the radial direction is set to be relatively large only in the circumferential intermediate portion 32a, not in the entire circumferential direction of each locking upper surface 36 of the locking protrusion 32. Therefore, it is avoided as much as possible that the breaking line 14 is accidentally broken when the locking projection 32 elastically climbs over the locking jaw 48.

  When opening the mouth-and-neck portion 44 to consume the contents, the container lid 2 is rotated in the opening direction, that is, counterclockwise as viewed from above in FIG. As a result, the male thread 46 and the male thread 26 are gradually disengaged, and the main portion 16 of the skirt wall 6 is moved upward in the axial direction along with the rotation. On the other hand, the tamper evidence skirt 18 is prevented from moving upward in the axial direction because the locking protrusion 32 is locked to the locking jaw 48, and thus stress is generated in the bridging portion 22 of the breaking line 14. The bridging portion 22 is broken, and the tamper evidence skirt 18 is separated from the main portion 16 of the skirt wall 6. After the breaking line 14 is broken, the tamper evidence skirt 18 remains in the mouth neck portion 44, and the top wall 4 of the container lid 2 and the main portion 16 of the skirt wall 6 are free to move upward in the axial direction along with the rotation. Is moved away from the mouth / neck 44 and thus the mouth / neck 44 is opened. If desired, an axial break line is formed in the tamper evidence skirt 18 and when the container neck 44 is opened, the axial break line is broken, while the break line 14 extends in the circumferential direction. One end of the container lid 2 is maintained without being broken, and the tamper evidence skirt 18 is expanded from the endless ring to the end ring, and the entire container lid 2 is detached from the mouth / neck 44 together with the tamper evidence skirt 18. It can also be done.

2: Container lid 4: Top wall 6: Skirt wall 14: Break line 16: Main part of skirt wall 18: Tamper evidence hem 22: Bridge 26: Female thread 26a: Lower female thread 26b: Upper female Thread 28a: Lower female thread interruption region 28b: Upper female screw interruption region 30a: Female screw portion 30b: Female screw portion 32: Locking projection 32a: Middle portion of locking protrusion in the circumferential direction 32b: Engagement Both sides of the locking projection in the circumferential direction 34: Locking projection non-existing portion 36: Locking top surface of the locking projection 44: Mouth and neck portion 46: Male screw 46a: Lower male screw 46b: Upper male screw 48: Locking Chin

Claims (5)

A circular skirt wall and a cylindrical skirt wall depending from the peripheral edge of the top wall. A rupture line extending in the circumferential direction is formed in the skirt wall, and the skirt wall is a main skirt wall above the rupture line. And a tamper-evidence hem part below the break line, and an internal thread is formed on the inner peripheral surface of the main part of the skirt wall, and the tamper-evidence hem part A plurality of locking projections extending in the circumferential direction are disposed on the inner peripheral surface at intervals in the circumferential direction, and each of the locking projections has a locking upper surface extending inward in the radial direction. In the plastic container lid,
The female thread is composed of a plurality of female thread parts interrupted by a plurality of interrupting regions arranged at intervals in the circumferential direction,
The female threaded portion exists at least in the axial direction of the middle portion of the locking projection in the circumferential direction.
A synthetic resin container lid.   The radial extension length of the locking upper surface at the circumferential intermediate portion of the locking projection is larger than the radial extension length of the locking upper surface at both circumferential sides of the locking projection. The synthetic resin container lid according to 1.   The extending length in the radial direction of the locking upper surface in the circumferential intermediate portion of the locking projection is gradually reduced from the center in the circumferential direction toward both sides in the circumferential direction. The radially extending length of the locking upper surface is gradually reduced toward both sides in the circumferential direction, is zero at both circumferential ends, and the radial direction of the locking upper surface at both circumferential ends of the circumferential intermediate portion 3. The synthetic resin container lid according to claim 2, wherein the extending length is the same as the extending length in the radial direction of the locking upper surface at the inner end in the circumferential direction on both sides in the circumferential direction.   The locking projections are arranged in an odd number at an equal interval in the circumferential direction, and an odd number is arranged, the circumferential length of each of the locking projections is the same, and the interruption region of the female thread is the circumference. An integer multiple of N is provided at equal intervals in the direction, and the circumferential center of the locking projection is aligned with the circumferential center of the female thread portion in the axial direction. The synthetic resin container lid according to any of the above.   The synthetic resin container lid according to claim 4, wherein N is 5. 5.