Synthetic resin container lid

Abstract

To provide a novel synthetic resin container lid by which a tamper-evident piece 68 separated from a skirt wall 54 is supported without depending on a shape of a neck part of an attached container.SOLUTION: The tamper-evident piece 68 separated from an upper lid 6 is caused to be supported by not a neck part of a container but a container lid itself, when the upper lid 6 is turned from a closed position to an open position.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a container lid having a lid body and a top cover connected to the lid body via hinge means and capable of pivoting between a closed position covering the top surface of the lid body and an open position exposing the top surface of the lid body. [Background technology]

[0002] The following Patent Document 1 shows an example of a synthetic resin container lid having a lid body and a top lid connected to the lid body via a hinge means and rotatable between a closed position that covers the top surface of the lid body and an open position that exposes the top surface of the lid body. The lid body includes a closing wall and a cylindrical mounting wall that hangs down from the periphery of the closing wall, and the top lid includes a top wall and a cylindrical skirt wall that hangs down from the periphery of the top wall. A tamper-evident piece is disposed on the skirt wall via a breakable weakened portion, and the tamper-evident piece includes a locking means, and the mounting wall includes a locked means. The locking means is composed of a column portion that extends radially inward from the inner surface of the tamper-evident piece and a pair of protrusions that protrude on both sides in the circumferential direction at the tip of the column portion. On the other hand, the locked means is composed of a groove that penetrates from the inner surface of the skirt wall to the outer surface, extends in the vertical direction, and has a closed upper end and an open lower end. When the top cover is rotated to the closed position, a pillar portion that is a part of the locking means is fitted into a groove that constitutes the locked means. When the top cover is rotated from the closed position to the open position, the locking means is locked to the locked means, i.e., the pillar portion of the locking means is locked to the upper end of the groove that constitutes the locked means, causing stress to concentrate on the breakable weakened portion, which breaks, and the tamper-evident piece is separated from the skirt wall. With the tamper-evident piece separated from the skirt wall, it is clearly indicated to the cover body that the top cover has been opened, i.e., tamper-evident properties are ensured. The tamper-evident piece that has separated from the skirt wall falls due to gravity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-18957 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the container lid shown in the above Patent Document 1, the tamper-evident piece separated from the skirt wall is supported by a support ring formed on the outer circumferential surface of the mouth and neck of the container, not by the container lid. Therefore, the tamper-evident piece is not sufficiently supported by the tamper-evident piece, and there is a risk that the tamper-evident piece may fall unintentionally when the container or the container lid is gripped. In addition, when the container lid and the container are separated and discarded after use, the tamper-evident piece is highly likely to fall alone because it is separated from the container lid. If the tamper-evident piece falls, it must be picked up, which is cumbersome.

[0005] The present invention has been made in consideration of the above-mentioned facts, and its main technical object is to provide a new and improved synthetic resin container lid in which a tamper-evident piece separated from a skirt wall is supported regardless of the shape of the mouth and neck of the container to which it is attached. [Means for solving the problem]

[0006] After careful consideration, the inventors discovered that the above-mentioned main technical problem can be solved by ensuring that the tamper-evident piece that is detached from the top lid when the top lid is pivoted from the closed position to the open position is supported by the container lid itself rather than the mouth and neck of the container.

[0007] That is, according to the present invention, a synthetic resin container lid that solves the above-mentioned main technical problem comprises a lid body, and a top lid that is connected to the lid body via a hinge means and can be rotated between a closed position that covers an upper surface of the lid body and an open position that exposes an upper surface of the lid body, the lid body includes a closing wall and a cylindrical mounting wall depending from a peripheral edge of the closing wall, and the upper lid includes a top wall and a cylindrical skirt wall depending from a peripheral edge of the top wall, A tamper-evident piece is disposed on the skirt wall via a breakable weakened portion, a tamper-evident piece provided with a locking means and a mounting wall provided with a locking means, the locking means being combined with the locking means when the top cover is in the closed position, and the breakable weakened portion being broken to separate the tamper-evident piece from the skirt wall when the top cover is rotated from the closed position to the open position, The synthetic resin container lid is characterized in that the locking means is a hole formed on the inner surface of the tamper-evident piece, with the upper and lower ends closed, and the locking means comprises a column extending radially outward from the outer surface of the mounting wall and a protrusion formed on the outer surface of the column, and the locking means is combined with the locking means by the protrusion elastically climbing over the periphery of the locking means.

[0008] Preferably, the breakable weakened portion is formed on the underside of the skirt wall. The protrusion preferably protrudes on both circumferential sides at the tip of the column. Preferably, in a plan view with the top cover in the closed position, the locking means and the locked means are aligned on the diametrically opposite side to the hinge means. In this case, a flange is formed on the upper end of the outer circumferential surface of the top wall at a location diametrically opposite to the hinge means, and when the top cover is in the closed position, the flange protrudes radially outward beyond the locked means. Preferably, the locking means is a groove extending vertically from the inner surface to the outer surface of the tamper-evident piece. In a state where the locking means and the locked means are combined and before the breakable weakened portion is broken, it is preferable that the lower end of the tamper-evident piece is located at the same height as or higher than the lower end of the mounting wall, and when the breakable weakened portion is broken, the lower end of the tamper-evident piece is displaced below the lower end of the mounting wall. On the outer peripheral surface of the mounting wall, on the diametrically opposite side to the hinge means, a pair of auxiliary ridges extending linearly in the vertical direction are arranged in parallel with a space in the circumferential direction, and when the locking means is combined with the locked means, it is preferable that the tamper-evident piece is located between each of the pair of auxiliary ridges. In this case, it is preferable that the lower end of each of the pair of auxiliary ridges has a protruding piece protruding in a direction approaching each other at an edge portion connecting the mutually facing inner surface and the radially outer surface. Effect of the Invention

[0009] In the synthetic resin container lid constructed according to the present invention, the locking means is a hole formed on the inner surface of the tamper-evident piece, and both the upper and lower ends are closed, and the locked means includes a column extending radially outward from the outer surface of the mounting wall and a protrusion formed on the outer surface of the column, and the protrusion elastically overcomes the periphery of the locking means, so that the locking means is combined with the locked means. Therefore, the tamper-evident piece separated when the top lid is rotated from the closed position to the open position falls freely once due to gravity, but is supported by the upper end of the hole constituting the locking means as it abuts against a part of the locked means. In other words, with the synthetic resin container lid constructed according to the present invention, the tamper-evident piece is supported by the lid body even when it is separated from the skirt wall, and is supported regardless of the shape of the mouth and neck of the container to which the container lid is attached. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view of one embodiment of a synthetic resin container lid constructed in accordance with the present invention with the top lid in an open position; [Diagram 2] FIG. 2 is a bottom view of the state shown in FIG. 1 . [Diagram 3] FIG. 2 is a front view of the state shown in FIG. 1 with the top cover omitted. [Figure 4] 2 is a rear view of the state shown in FIG. 1 with the lid body omitted. FIG. [Diagram 5] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 6] 2 is a front view of the container lid shown in FIG. 1 when the top lid is in a closed position. [Figure 7] 7 is a bottom view of the state shown in FIG. 6. [Figure 8] 7 is a cross-sectional view taken along line AA in FIG. 6. [Figure 9] 9 is a vertical cross-sectional view of the top cover when it is pivoted from the state shown in FIG. 8 to the open position. [Figure 10] 10 is a longitudinal sectional view of the state shown in FIG. 9 after the removal region has been removed. [Figure 11] 11 is a front view of the top cover when it is rotated to a closed position from the state shown in FIG. 10. [Figure 12] 3 in another embodiment of a synthetic resin container lid constructed according to the present invention. FIG. [Figure 13] 13 is a view corresponding to FIG. 6 of the container lid shown in FIG. 12. [Figure 14] 13 is a view corresponding to FIG. 7 of the container lid shown in FIG. 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a more detailed description will be given with reference to the attached drawings showing one embodiment of a synthetic resin container lid constructed according to the present invention. Here, unless otherwise specified, the up-down direction in this specification is based on a state in which the top lid is in a closed position, which will be described later. Therefore, when the top lid is in an open position, which will be described later, the up-down direction is reversed.

[0012] 1 to 5, a synthetic resin container lid generally designated by the numeral 2 comprises a lid body 4 and a top lid 6, and the lid body 4 and the top lid 6 are connected via a hinge means 8. The container lid 2 is integrally molded in the state shown in Figs. 1 to 5, that is, with the top lid 6 in an open position described below.

[0013] Explaining mainly with reference to Figures 1 and 5, the cover body 4 has a blocking wall 10 and a cylindrical mounting wall 12 that hangs down from the periphery of the blocking wall 10. The blocking wall 10 is circular in plan view, i.e., in Figure 1, and is divided into a removal area 16 surrounded by a breakable thin-wall line 14 and a remaining area 18 outside the breakable thin-wall line 14. The breakable thin-wall line 14 is formed by an annular groove formed on the lower surface of the blocking wall 10 (see also Figure 2). The removal area 16 is disposed in the center of the blocking wall 10, and is divided into a circular central portion 20 and a pair of extensions 22a and 22b that locally extend radially outward from the outer circumferential surface of the central portion 20 toward the side where the hinge means 8 is present and the opposite side, respectively. A well-known pull ring 24 is connected to the upper surface of the extension 22a.

[0014] A generally cylindrical pouring guide wall 36 extending upward is disposed on the upper surface of the blocking wall 10 at the outer peripheral edge of the remaining area 18. The upper end of the pouring guide wall 36 is curved radially outward. A cylindrical locking wall 38 is disposed on the upper surface of the blocking wall 10 outside the pouring guide wall 36, and an annular locking protrusion 40 is formed at the upper end of the outer peripheral surface of the locking wall 38. A cylindrical seal wall 42 hanging downward is formed on the lower surface of the blocking wall 10 at the outer peripheral edge of the remaining area 18, and the outer peripheral surface of the seal wall 42 faces the inner peripheral surface of the mounting wall 12 at a radial distance.

[0015] 2 and 5, a locking means 46 is provided at the lower end of the inner peripheral surface of the mounting wall 12, protruding radially inward. In the illustrated embodiment, the locking means 46 is formed of an annular ridge extending continuously in the circumferential direction. 1 and 3, a pair of auxiliary ridges 48a and 48b extending linearly in the vertical direction are provided in parallel with a space between them in the circumferential direction on the radially opposite side of the hinge means 8 on the outer peripheral surface of the mounting wall 12. A substantially rectangular recess 50 is also formed between the pair of auxiliary ridges 48a and 48b. A locking means is provided below the recess 50. The locking means will be described later.

[0016] 1 and 5, the top cover 6 has a circular top wall 52 extending substantially horizontally and a cylindrical skirt wall 54 hanging down from the periphery of the top wall 52. The lower end of the outer circumferential surface of the skirt wall 54 is connected to the upper end of the outer circumferential surface of the mounting wall 12 of the cover body 4 via a hinge means 8, and the top cover 6 can be rotated between a closed position (for example, the state shown in FIG. 8) in which the cover body 4 covers the closing wall 10 and an open position (for example, the state shown in FIG. 5) in which the cover body 4 exposes the closing wall 10. A cylindrical hanging wall 58 hanging down is formed on the outer circumferential edge of the lower surface of the top wall 52. A flange 60 protruding outward in the radial direction is provided at the portion of the outer circumferential surface upper end of the skirt wall 54 opposite the hinge means 8 in the diametric direction, and the flange 60 can be hooked with a finger when the top cover 6 is turned open or closed. A ring-shaped engaging protrusion 62 is disposed on the lower end of the inner peripheral surface of the skirt wall 54. A ring-shaped abutment shoulder surface 64 facing downward is formed above the engaging protrusion 62. Referring also to FIG. 4, a tamper-evident piece 68 is further disposed on the skirt wall 54 via a breakable weakened portion 66. In the illustrated embodiment, the breakable weakened portion 66 is a bridge portion formed on the lower surface of the skirt wall 54. If desired, the breakable weakened portion may be a thin portion or may be disposed on the outer surface of the skirt wall 54. The tamper-evident piece 68 is a thin plate piece of a substantially rectangular shape, on which a locking means is disposed. The locking means will be described later.

[0017] 3 to 5 together with FIG. 1, the locking means 70 provided on the tamper-evident piece 68 and the locked means 72 provided on the mounting wall 12 will be described. As shown in FIG. 1, in a plan view with the top cover 6 in the open position, the locking means 70 and the locked means 72 are disposed at positions on the diametrically opposite sides of the top cover 6 and the hinge means 8 on the cover body 4, respectively. Therefore, when the top cover 6 is turned to the closed position as described below, the locking means 70 and the locked means 72 are aligned on the opposite sides of the hinge means 8 in a plan view. As long as the locking means 70 and the locked means 72 are aligned in a plan view when the top cover 6 is turned to the closed position, the locking means 70 and the locked means 72 may be disposed at any circumferential positions. In the illustrated embodiment, the locking means 70 is a groove that extends vertically from the inner surface to the outer surface of the tamper-evident piece 68 (hereinafter the locking means may be referred to as a groove), and the upper and lower ends of the groove 70 are closed. The locked means 72 includes a pillar portion 74 that extends radially outward from the outer surface of the mounting wall 12, and a protrusion 76 that protrudes in the circumferential direction from the tip of the pillar portion 74. The locked means 72 is disposed below the recess 50, and the protrusions 76 protrude on both circumferential sides from the tip of the pillar portion 74.

[0018] As described above, the container lid 2 is molded integrally with the top lid 6 in the open position, and after molding, the top lid 6 is rotated from the open position to the closed position. When the top lid 6 is rotated to the closed position, as shown in Fig. 8, the abutment shoulder surface 64 formed on the inner surface of the skirt wall 54 of the top lid 6 abuts against the upper surface of the locking wall 38 of the lid body 4, and the locked protrusion 62 elastically overcomes the locking protrusion 40 and is locked thereto, so that the top lid 6 is held in the closed position. When the top lid 6 is in the closed position, the outer surface of the lower end of the hanging wall 58 formed on the top wall 52 of the top lid 6 is in close contact with the inner surface of the pouring guide wall 36 formed on the lid body 4. Explaining with reference to Figures 3 and 4, thereafter, the groove 70 of the tamper-evident piece 68 arranged on the top cover 6 is aligned with the locking means 72 arranged on the cover body 4, and the tamper-evident piece 68 is pressed radially inward to cause the protrusion 76 to elastically climb over the periphery of the groove 70. Thus, as shown in Figure 6, the locking means (groove) 70 is combined with the locking means 72. In a state in which the locking means 70 is combined with the locking means 72, the protrusion 76 is locked in the groove 70, and therefore it is not possible to release the lock between the protrusion 76 and the groove 70 without breaking the breakable weakened portion 66. In a state where the locking means 70 and the locked means 72 are combined and before the breakable weakened portion 66 is broken, the locked means 72 is located at the lower end of the groove 70, and the lower end of the tamper-evident piece 68 is located above the lower end of the mounting wall 12. If desired, the lower end of the tamper-evident piece 68 may be at the same height as the lower end of the mounting wall 12. Usually, the container lid 2 is transported with the top lid 6 in the closed position and the locking means 70 combined with the locked means 72. At this time, the tamper-evident piece 68 is disposed between the pair of auxiliary protrusions 48a and 48b, which protect at least the side surface of the tamper-evident piece 68 and prevent the breakable bridge portion 66 from being broken unexpectedly as much as possible.

[0019] 8 shows, by a two-dot chain line, a container lid 2 constructed according to the present invention as well as a neck of a container to which the container lid 2 is applied. The neck of the container 100, which can be formed from a suitable synthetic resin or glass, has a cylindrical shape with an open top, and a mating ridge 102 is formed on the upper end of its outer circumferential surface. A support ring 104 (used when transporting the container) is also formed on the outer circumferential surface of the neck of the container, located below the mating ridge 102.

[0020] When the container lid 2 is attached to the mouth and neck part 100 to seal it after the contents are placed in the container, the container lid 2, more specifically, the container lid 2 with the top lid 6 in the closed position relative to the lid body 4 and the locking means 70 combined with the locked means 72 is fitted onto the mouth and neck part 100 and forced downward. Then, the locking means 46 formed on the inner peripheral surface of the mounting wall 12 elastically rides downward over the fitting ridge 102 of the mouth and neck part 100 and is locked thereto.

[0021] When discharging the contents of the container, a finger is put on the underside of the flange 60 of the top lid 6, and an upward force is applied to the flange 60 with the hinge means 8 as the center of rotation. At this time, as can be understood by referring to Figures 6 and 7, the flange 60 protrudes radially outward from the locked means 72, so that the finger can be put on the underside of the flange 60 without the locked means 72 interfering with the finger excessively. The upward force causes the top lid 6 to rotate from the closed position to the open position, that is, to rotate in the opening direction. At this time, the tamper-evident piece 68 also tries to rotate in the opening direction. When the tamper-evident piece 68 rotates in the opening direction, that is, moves upward, the locked means 72 formed on the lid main body 4 moves relatively downward within the groove 70 (locking means) formed in the tamper-evident piece 68, and the pillar portion 74, which is a part of the locked means 72, is locked to the lower end of the groove 70. When the above-mentioned upward force is further applied from the state in which the pillar portion 74 is engaged with the lower end of the groove 70, stress is concentrated on the breakable weakened portion 66 connecting the skirt wall 54 of the top cover 6 and the tamper-evident piece 68, causing it to break, and the tamper-evident piece 68 is separated from the top cover 6. After the breakable weakened portion 66 is broken, the top cover 6 continues to rotate in the opening direction. Meanwhile, the tamper-evident piece 68 separated from the top cover 6 falls due to gravity, and the upper end of the groove 70 is supported by the pillar portion 74, which is a part of the engaging means 72, as shown in FIG. 9. At this time, the lower end of the tamper-evident piece 68 is located below the lower end of the mounting wall 12. When the tamper-evident piece 68 is separated from the skirt wall 54, it becomes clear that the top cover 6 has been opened relative to the cover body 4, thereby ensuring so-called tamper-evident properties.

[0022] Therefore, with a synthetic resin container lid constructed according to the present invention, the tamper-evident piece 68 is supported by the lid body 4 even if it is separated from the skirt wall 54, and is therefore supported regardless of the shape of the neck of the container to which the container lid is attached.

[0023] After the top cover 6 is rotated to the open position, the pull ring 24 of the cover body 4 is hooked with a finger and forced upward to break the breakable thin-wall line 14 and remove the removal area 16 from the closing wall 10. Thus, as shown in FIG. 10, a discharge opening 78 is generated in the closing wall 10. Thereafter, the container is appropriately tilted to discharge the contents of the container through the discharge opening 78. After the contents have been discharged, the container is turned upright, and then the top cover 6 is rotated to the closed position with the hinge means 8 as the rotation center in the closing direction, i.e., in the direction covering the closing wall 10, as shown in FIG. 11. At this time, as can be clearly understood by comparing FIG. 11 with FIG. 6, the tamper-evident piece 68 is separated from the skirt wall 54, and it is found that the top cover 6 has been opened relative to the cover body 4.

[0024] Figures 12 to 14 show another embodiment of a synthetic resin container lid constructed according to the present invention. Figures 12 to 14 are views corresponding to Figures 3, 6, and 7 of the container lid 2 described above, respectively. Since the configuration of the container lid of this embodiment is similar to the configuration of the container lid 2 described above, in the following, the same components as those of the container lid 2 described above will be marked with "'" and detailed description thereof will be omitted, and only the different components will be described.

[0025] First, referring to Figures 12 and 14, in the container lid 2', a protruding piece 49a' is formed on the auxiliary ridge 48a' provided on the outer circumferential surface of the mounting wall 12' of the lid body 4', and a protruding piece 49b' is formed on the auxiliary ridge 48b'. The protruding pieces 49a' and 49b' protrude in a direction approaching each other from the edge connecting the mutually opposing inner surface and the radially outer surface at the lower end of each of the auxiliary ridges 48a' and 48b'. Continuing the explanation with reference to Figures 12 to 14, the container lid 2' is also integrally formed with the top lid 6' in the open position, and the top lid 6' is rotated from the open position to the closed position. When the top cover 6' is turned to the closed position, the peripheral portion of the groove 70' on the radially inner surface of the tamper-evident piece 68' arranged on the top cover 6' comes into contact with the radially outer surface of the locking means 72' arranged on the mounting wall 12' of the cover body 4'. Next, both side edges of the tamper-evident piece 68' are pressed radially inward by a required jig, so that both side edges of the tamper-evident piece 68' climb over the protruding pieces 49a' and 49b' and are positioned between the protruding pieces 49a' and 49b' and the outer circumferential surface of the mounting wall 12'. After that, the center portion of the tamper-evident piece 68' is pressed radially inward, so that the peripheral edge of the groove 70' elastically climbs over the protruding portion 76' of the locking means 72'. After the tamper-evident piece 68 is pressed radially inward as described above, both side edges of the lower end of the tamper-evident piece 68' are positioned between the protruding pieces 49a' and 49b' and the outer circumferential surface of the mounting wall 12'. As a result, in this embodiment, in a state in which the locking means (groove 70') and the locked means 72' are combined and before the breakable weakened portion 66' is broken, the tamper-evident piece 68' is protected not only at its sides by the auxiliary protrusions 48a' and 48b' but also at its lower end by the protruding pieces 49a' and 49b', so that the breakable bridging portion 66' is further prevented from being broken unexpectedly.

[0026] The synthetic resin container lid constructed according to the present invention has been described in detail above with reference to the attached drawings, but the present invention is not limited to the above-mentioned embodiment, and appropriate modifications and changes are possible within the scope of the present invention. For example, as described above, when the top cover 6 is brought to the closed position, the protrusion of the locking means 72 elastically overcomes the periphery of the locking means so that the locking means is combined with the locking means, and when the top cover is rotated in the opening direction from the state in which the locking means is combined with the locking means, the configuration of the locking means and the locked means may be arbitrary. Therefore, in the illustrated embodiment, the locking means is a groove 70 extending in the vertical direction, but if desired, it may be a hole of any shape, such as a circle. In addition, the hole constituting the locking means does not necessarily have to penetrate from the inner surface to the outer surface of the tamper-evident piece 68. If the hole does not penetrate, the locked means is provided on the inner peripheral surface of the hole. Furthermore, the protrusion formed on the locked means does not necessarily have to be formed at the tip of the column, but may be formed at the middle of the column. [Explanation of symbols]

[0027] 2: Container lid 4: Lid body 6:Top lid 8: Hinge means 10:Occluded wall 12: Mounting wall 14: Breakable thin-walled line 52: Top wall 54: Skirt wall 66: Breakable weakened section 68: Tamper evident piece 70: Locking means / groove 72: Locked means 74: Pillar part 76: Protrusion

Claims

1. The container comprises a lid body, and a top lid connected to the lid body via a hinge means and rotatable between a closed position covering an upper surface of the lid body and an open position exposing an upper surface of the lid body, the lid body includes a closing wall and a cylindrical mounting wall depending from a peripheral edge of the closing wall, and the upper lid includes a top wall and a cylindrical skirt wall depending from a peripheral edge of the top wall, A tamper-evident piece is disposed on the skirt wall via a breakable weakened portion, a tamper-evident piece provided with a locking means and a mounting wall provided with a locking means, the locking means being combined with the locking means when the top cover is in the closed position, and the breakable weakened portion being broken to separate the tamper-evident piece from the skirt wall when the top cover is rotated from the closed position to the open position, A synthetic resin container lid characterized in that the locking means is a hole formed on the inner surface of the tamper-evident piece, with the upper and lower ends closed, and the locked means comprises a column extending radially outward from the outer surface of the mounting wall and a protrusion formed on the outer surface of the column, and the locking means is combined with the locked means by the protrusion elastically overcoming the periphery of the locking means.

2. 2. The synthetic resin container lid according to claim 1, wherein said breakable weakened portion is formed on the underside of said skirt wall.

3. 2. The synthetic resin container lid according to claim 1, wherein said protrusions protrude on both circumferential sides at the tip of said column portion.

4. 2. The synthetic resin container lid according to claim 1, wherein, in a plan view when the top lid is in the closed position, the locking means and the locked means are aligned on a diametrically opposite side to the hinge means.

5. A synthetic resin container lid as described in claim 4, wherein a flange portion is formed at the upper end of the outer peripheral surface of the top wall at a portion diametrically opposite the hinge means, and when the top lid is in the closed position, the flange portion protrudes radially outward beyond the engaging means.

6. 2. The synthetic resin container lid according to claim 1, wherein said locking means is a groove extending vertically from the inner surface to the outer surface of said tamper-evident piece.

7. 2. A synthetic resin container lid as described in claim 1, wherein when the locking means and the locked means are combined and before the breakable weakened portion is broken, the lower end of the tamper-evident piece is located at the same height as or higher than the lower end of the mounting wall, and when the breakable weakened portion is broken, the lower end of the tamper-evident piece is displaced downwardly below the lower end of the mounting wall.

8. A synthetic resin container lid as described in claim 1, wherein a pair of auxiliary protrusions extending linearly in the vertical direction are arranged in parallel at intervals in the circumferential direction on the outer peripheral surface of the mounting wall on the diametrically opposite side of the hinge means, and when the locking means is combined with the locked means, the tamper-evident piece is positioned between each of the pair of auxiliary protrusions.

9. 9. A synthetic resin container lid as described in claim 8, wherein the edges connecting the mutually opposing inner surfaces and radially outer surfaces at the lower ends of each of the pair of auxiliary protrusions are each formed with a protruding piece protruding in directions approaching each other.

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