SYNTHETIC RESIN CONTAINER LID

Abstract

A cap-type synthetic resin container lid (2), which can be removed sufficiently easily from a mouth-neck section (38) of a container without requiring great force and, even after removal from the mouth-neck section (38) of the container, continues to be kept integral without being partly separated to form a scrap piece, is provided.

The container lid (2) includes thin-walled inversion pieces (18) arranged at intervals in the circumferential direction and extending upward beyond a top panel wall (4) from the lower ends of the thin-walled inversion pieces, the lower ends being connected to the outer peripheral surface of a skirt wall (6) or to the boundary part between the outer peripheral surface of the skirt wall (6) and the upper surface of the top panel wall (4); a restraint wall (20) connected to the upper ends of the thin-walled inversion pieces (18) and having a specific site (22) in the circumferential direction, the specific site being either split, or being defined by a breakable weakened section (24); and an operating section (30) connected to the outer peripheral surface of the skirt wall (6) via a connecting piece (28) extending out radially from the outer peripheral surface of the skirt wall (6) at a position in alignment with the specific site (22). Locked projections (26) and locking projections (36) are disposed in the restraint wall (20) and the connecting piece (28), respectively, to collaborate in restricting the expansion of the restraint wall (20).

Claims

1. A synthetic resin container lid including a circular top panel wall, and a skirt wall extending downwardly from a peripheral edge of the top panel wall, a locking ridge being formed on an inner peripheral surface of the skirt wall, wherein a plurality of thin-walled inversion pieces extending upward beyond the top panel wall from lower ends of the thin-walled inversion pieces are arranged at intervals in a circumferential direction, the lower ends being connected to an outer peripheral surface of the skirt wall or to a boundary part between the outer peripheral surface of the skirt wall and an upper surface of the top panel wall; a restraint wall is connected to upper ends of the thin-walled inversion pieces, a specific site in the circumferential direction of the restraint wall is either split, or is defined by a breakable weakened section, and locked projections protruding radially outwardly from an outer peripheral surface of the restraint wall are formed on both sides in the circumferential direction of the specific site; an operating section is connected to the outer peripheral surface of the skirt wall via a connecting piece extending out radially from the outer peripheral surface of the skirt wall, the connecting piece is located in alignment with the specific site in the circumferential direction, and locking projections protruding radially inwardly are formed in the operating section on both sides in the circumferential direction of the connecting piece; and when the thin-walled inversion pieces are inverted to extend downward from the lower ends, the restraint wall surrounds the skirt wall, and the locked projections and the locking projections collaborate to restrict expansion of the restraint wall.

2. The synthetic resin container lid according to claim 1, wherein when the thin-walled inversion pieces are inverted to extend downward from the lower ends, the connecting piece acts on the weakened section to break the weakened section.

3. The synthetic resin container lid according to claim 1, wherein the operating section includes a ring over which fingers can be hooked,

4. The synthetic resin container lid according to claim 1, wherein a plurality of slits extending upward from a lower end of the skirt wall are formed at intervals in the circumferential direction in the skirt wall.

5. The synthetic resin container lid according to claim 1, wherein an inner diameter of parts in the restraint wall aligning with the thin-walled inversion pieces in the circumferential direction is set to be larger than an inner diameter of other parts except the specific site, and the inner diameter of the other parts is brought into correspondence with an outer diameter of the skirt wall.

6. The synthetic resin container lid according to claim 1, wherein a plurality of concavities extending from a lower end to an upper end of the skirt wall are arranged at intervals in the circumferential direction in the outer peripheral surface of the skirt wall, and the lower ends of the thin-walled inversion pieces are connected to the concavities.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] [FIG. 1] is a perspective view showing a preferred embodiment of a synthetic resin container lid configured in accordance with the present invention.

[0015] [FIG. 2] is a bottom view of the container lid shown in FIG. 1.

[0016] [FIG. 3] is a sectional view on line in FIG. 2.

[0017] [FIG. 4] is a perspective view showing the intermediate stage of a mounting operation for mounting the container lid shown in FIG. 1 on a mouth-neck section of a container.

[0018] [FIG. 5] is a sectional view showing the intermediate stage of the mounting operation for mounting the container lid shown in FIG. 1 on the mouth-neck section of the container.

[0019] [FIG. 6] is a perspective view showing a state in which the container lid shown in FIG. 1 has been mounted on the mouth-neck section of the container,

[0020] [FIG. 7] is a sectional view showing a state in which the container lid shown in FIG. 1 has been mounted on the mouth-neck section of the container.

[0021] [FIG. 8] is a perspective view showing the intermediate stage of a removal operation for removing the container lid shown in FIG. 1, which has been mounted on the mouth-neck section of the container, from the mouth-neck section.

[0022] [FIG. 9] is a sectional view showing the intermediate stage of the removal operation for removing the container lid shown in FIG. 1, which has been mounted on the mouth-neck section of the container, from the mouth-neck section.

[0023] [FIG. 10] is a perspective view showing the final stage of the removal operation for removing the container lid shown in FIG. 1, which has been mounted on the mouth-neck section of the container, from the mouth-neck section.

[0024] [FIG. 11] is a sectional view showing the final stage of the removal operation for removing the container lid shown in FIG. 1, which has been mounted on the mouth-neck section of the container, from the mouth-neck section.

MODE FOR CARRYING OUT THE INVENTION

[0025] The present invention will now be described in further detail by reference to the accompanying drawings showing a synthetic resin container lid configured in accordance with the present invention.

[0026] With reference to FIGS. 1 to 3, a container lid illustrated there and entirely indicated at 2, which can be integrally injection or compression molded from a suitable synthetic resin such as polyethylene or polypropylene, comprises a top panel wall 4, and a skirt wall 6 extending downwardly from the peripheral edge of the top panel wall 4. The top panel wall 4 is circular in a plan view, and has a flat middle part, and a peripheral edge part inclined downwardly in a radially outward direction. As clearly shown in FIG. 3, two annular sealing pieces extending out downwardly, namely, an inner sealing piece 8 and an outer sealing piece 10, are disposed in a peripheral edge part of the inner surface of the top panel wall 4.

[0027] The skirt wall 6 is nearly cylindrical as a whole. An annular locking ridge 12 is formed in a lower end part of the inner peripheral surface of the skirt wall 6. As will be clearly understood by reference to FIGS. 1 and 3, a plurality of, twelve in the drawings, slits 14 extending upward from the lower end of the skirt wall 6 are formed in a lower end part of the skirt wall 6. A plurality of, five in the drawings, concavities 16 extending from the lower end to the upper end of the skirt wall 6 are arranged at intervals in the circumferential direction in the outer peripheral surface of the skirt wall 6. The lower ends of thin-walled inversion pieces 18 are connected to upper parts of the concavities 16. The thin-walled inversion pieces 18 are extended out upwardly beyond the top panel wall 4. If desired, the lower ends of the thin-walled inversion pieces 18 can be connected to a boundary region between the skirt wall 6 and the top panel wall 4, instead of to the outer peripheral surface of the skirt wall 6.

[0028] A restraint wall 20 is connected to the upper ends of the thin-walled inversion pieces 18. The restraint wall 20 is of a nearly toroidal shape, and a specific site 22 thereof in its circumferential direction is defined by a breakable weakened section 24 composed of a bridging piece having a small cross-sectional area. If desired, an extremely weak site having a decreased cross-sectional area can be formed, for example, in a circumferentially middle part of the bridging piece constituting the weakened section 24. Furthermore, the restraint wall 20 can be split at the specific site 22 without disposing the weakened section 24. If the weakened section 24 is disposed without splitting of the specific site 22, however, the torsion or excessive expansion of the restraint wall 20 can be avoided sufficiently reliably, when the container lid 2 is mounted on the mouth-neck section 38 of the container, as will be mentioned later. It is preferred, therefore, to dispose the weakened site 24 without splitting the specific site 22. In the illustrated embodiment, moreover, the weakened section 24 is disposed at the upper end part of the restraint wall. 20 in the axial direction, but can be disposed in the middle of the restraint wall 20 in the axial direction. On both sides of the specific site 22 in the circumferential direction, locked projections 26 protruding radially outwardly are formed. The circumferentially inside surfaces of the locked projections 26 (namely, the side surfaces adjacent to the specific site 22) extend in the radial direction, while the circumferentially outside surfaces of the locked projections 26 (namely, the side surfaces spaced from the specific site 22) are inclined surfaces extending circumferentially outwardly in a radially outward direction. As will be clearly understood by reference to FIG. 2 along with FIG. 1, at the plurality of sites where the thin walled inversion pieces 18 are present, the restraint wall 20 is locally somewhat displaced radially outwardly. At such sites, therefore, the inner diameter of the restraint wall 20 is locally somewhat increased as compared with the inner diameter of other parts except the specific site 22 (the inner diameter of such other parts corresponds to the outer diameter of parts of the skirt wall 6 where the concavities 16 have not been formed and, in other words, is nearly the same as the above outer diameter).

[0029] An operating section 30 is connected to the outer peripheral surface of the skirt wall 6 via a connecting piece 28 protruding radially outwardly. The circumferential position of the operating section 30 is in alignment with the circumferential position of the specific site 22 of the restraint wall 20. The operating section 30 is composed of a base 32 and a ring 34, and the inner surface of the base 32 is connected to the protruding end of the connecting piece 28. The base 32 extends out circumferentially bilaterally, and locking projections 36 protruding radially inwardly are formed on the inner surfaces of the opposite side ends located on both sides of the connecting piece 28. The circumferentially outside surfaces of the locking projections 36 (namely, the side surfaces spaced from the connecting piece 28) extend radially, while the circumferentially inside surfaces of the locking projections 36 (namely, the side surfaces adjacent to the connecting piece 28) are inclined surfaces inclined circumferentially inwardly in a radially inward direction. The ring 34 suspending from the base 32 is of a nearly toroidal shape.

[0030] A typical example of a mouth-neck section of a container to which the above container lid 2 is applied will be described by reference to FIG. 5. A mouth-neck section 38 of a container which can be molded from a suitable synthetic resin, such as polyethylene terephthalate, or glass is cylindrical as a whole, and an annular locking ridge 40 is formed in an upper end part of the outer peripheral surface of the mouth-neck section. In the illustrated embodiment, an annular groove is disposed in an axially middle part of the locking ridge 40. Below the locking ridge 40, a support ring 42 to be utilized during transport of the container is formed.

[0031] In mounting the container lid 2 on the mouth-neck section 38 of the container to seal the mouth-neck section 38, the container lid 2 is fitted onto the mouth-neck section 38 and urged downward. As a result, as shown in FIGS. 4 and 5, the locking ridge 12 formed in the lower end part of the inner peripheral surface of the skirt wall 6 elastically rides over the locking ridge 40 of the mouth-neck section 38, and becomes locked below it. The inner sealing piece 8 disposed in the peripheral edge part of the inner surface of the top panel wall 4 advances into the mouth-neck section 38, and intimately contacts the inner peripheral surface of the mouth-neck section 38, whereas the outer sealing piece 10 intimately contacts the outer peripheral surface of the mouth-neck section 36. Then, the restraint wall 20 is urged downward to invert the thin-walled inversion pieces 18, that is, to bring the thin-walled inversion pieces 18 into a state in which they extend downward from their lower ends connected to the outer peripheral surface of the skirt wall 6, as shown in FIGS. 6 and 7. At the sites of arrangement of the thin-walled inversion pieces 18, the concavities 16 are formed in the outer peripheral surface of the skirt wall 6, and the restraint wall 20 is locally somewhat displaced radially outwardly. Thus, the thin-walled inversion pieces 18 can be inverted sufficiently easily. When the thin-walled inversion pieces 18 are inverted, the restraint wall 20 surrounds the skirt wall 6 to inhibit the skirt wall 6 from being elastically deformed or displaced in the radially outward direction, so that the container lid 2 is firmly mounted on the mouth-neck section 38. When the restraint wall 20 is lowered to the position shown, in FIGS. 6 and 7, the connecting piece 28 disposed on the outer peripheral surface of the skirt wall 6 acts on the weakened section 24 of the restraint wall 20 to break the weakened section 24, as will be clearly understood by comparison between FIGS. 4, 5 and FIGS. 6, 7. If the extremely weak site is present circumferentially intermediately of the bridging piece constituting the weakened section 24, the breakage occurs at the extremely weak site. As clearly shown in FIG. 6, moreover, the locked projections 26 disposed in the restraint wall 20 and the locking projections 36 disposed in the operating section 30 are locked to each other, whereby the expansion of the restraint wall 20 is restricted and, more detailedly, the displacement of both sides of the specific site 22 in the direction of mutual separation is restricted. As will be understood by reference to FIG. 2, in the state prior to the mounting of the container lid 2 on the mouth-neck section 38 of the container, the circumferentially outside surfaces of the locked projections 26 are positioned circumferentially somewhat apart from the circumferentially inside surfaces of the locking projections 36. When the container lid 2 is mounted on the mouth-neck section 38 of the container in the above-mentioned manner, however, the restraint wall 20 is somewhat expanded. As a result, the circumferentially outside surfaces of the locked projections 26 contact or approach the circumferentially inside surfaces of the locking projections 36, as shown in FIG. 6.

[0032] In removing the container lid 2 from the mouth-neck section 38 of the container to unseal the mouth-neck section 38, the fingers are hooked over the ring 34 of the operating section 30 to displace the operating section 30 radially outwardly and upwardly. When the operating section 30 is displaced to the position shown in FIGS. 8 and 9, the mutual locking of the locking projections 36 disposed in the operating section 30 and the looked projections 26 disposed in the restraint wall 20 is released to permit the expansion of the restraint wall 20. Thus, the radially outward displacement of the skirt wail 6, in particular, its lower end part, is permitted. Consequently, the mutual locking between the locking ridge 12 formed at the lower end part of the inner peripheral surface of the skirt wall 6 and the locking ridge 40 of the Mouth-neck section 38 is partially released, whereby the skirt wall 6 is partly displaced upward. If the pressure inside the container is higher than the atmospheric pressure, the sealing of the mouth-neck section 38 is locally released at a time when the partial ascent of the skirt wall 6 begins. As a result, the pressure inside the container is released, thus preventing the container lid 2 from flying from the mouth-neck section 38 accidentally. When the ring 34 is then displaced upward toward a radially opposite side, the whole of the container lid 2 is removed from the mouth-neck section 38 to unseal the mouth-neck section 38, as will be clearly understood by reference to FIGS. 10 and 11.

[0033] The preferred embodiment of the container lid configured in accordance with the present invention has been described in detail by reference to the accompanying drawings. However, the present invention is not limited to such an embodiment, and various changes and modifications can be made without departing from the scope of the present invention. In the illustrated embodiment, for example, when the restraint wall 20 is lowered with respect to the skirt wall 6 in mounting the container lid 2 on the mouth-neck section 38 of the container, the weakened section 24 of the restraint wail 20 is broken. If desired, however, the present invention can be configured such that when the container lid 2 is mounted on the mouth-neck section 38, the connecting piece 28 or the operating section 30 does not act on the weakened section 24, but instead, when the operating section 30 is displaced in removing the container lid 2 from the mouth-neck section 38, the connecting piece 28 or the operating section 30 acts on the weakened section 24 to break it.

EXPLANATIONS OF LETTERS OR NUMERALS

[0034] 2: Container lid

[0035] 4: Top panel wail

[0036] 6: Skirt wall

[0037] 12: Locking ridge

[0038] 14: Slit

[0039] 16: Concavity

[0040] 18: Thin-walled inversion piece

[0041] 20: Restraint wall

[0042] 22: Specific site

[0043] 24: Weakened section

[0044] 26: Locked projection

[0045] 28: Connecting piece

[0046] 30: Operating section

[0047] 34: Ring

[0048] 36: Locking projection

[0049] 38: Mouth-neck section

[0050] 40: Locking ridge