Synthetic resin container lid

Abstract

To provide a new synthetic resin-made container lid which can be attached to and detached from a mouth part of a container without requiring a large force, has a simple manufacturing process, and suppresses a manufacturing cost.SOLUTION: A closing wall 4 and a cylindrical skirt wall 6 hanging down from the outer peripheral edge of the closing wall are provided. A locking projection 20 is formed on the outer peripheral surface of the skirt wall. On the lower surface of the skirt wall, a plurality of flap pieces 24 extending downward while inclining radially outward are arranged at intervals in the circumferential direction, and on the inner surface of each of the plurality of flap pieces 24, an engaging projection 26 projecting radially inward is formed. A cylindrical support wall 30 extending in the vertical direction is connected to the outer peripheral edge of the upper surface of the closing wall 4 or the outer peripheral surface of the skirt wall 6 through a weakened part 28. On the inner peripheral surface of the support wall, a reduced diameter lower part 32 having an inner diameter corresponding to the outer diameter of the closing wall 4 and connected to the weakened part 28 and an enlarged diameter upper part 34 having an inner diameter larger than the outer diameter of the closing wall 4 are defined, and the reduced diameter lower part 32 and the enlarged diameter upper part 34 are adjacent to each other in the vertical direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a synthetic resin container lid. [Background technology]

[0002] Patent Document 1 below shows an example of a synthetic resin container lid that is applied to the opening of a container such as a tube containing toothpaste, paste-like seasoning, etc. The container lid shown in Patent Document 1 includes a top wall and a cylindrical auxiliary wall that hangs down from the outer periphery of the top wall. A cylindrical locking wall that hangs down is provided on the underside of the top wall, and a locking protrusion that protrudes radially inward is formed at the lower end of the inner periphery of the locking wall. When attaching the container lid shown in Patent Document 1 to the opening of a container, the container lid is fitted onto the opening of the container and then pushed toward it. As a result, the locking protrusion formed on the inner periphery of the locking wall of the container lid elastically overcomes and locks onto the locking protrusion formed on the outer periphery of the opening of the container, thereby attaching the container lid to the opening of the container. When removing the container lid from the opening of the container, the outer periphery of the container lid is grasped and forcibly pulled up from the container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-81988 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the inventor's experience, when attaching or detaching the container lid shown in Patent Document 1 to or from the mouth of a container, the user grasps the container lid, more specifically the upper part of the outer peripheral surface of its auxiliary wall, and applies a radially inward force to it while pushing or pulling the container lid into or from the container, so that the locking protrusions formed on the container lid can easily climb over the locked protrusions formed on the mouth of the container. By applying this force to the outer peripheral surface of the auxiliary wall, the outer peripheral edge of the top wall bends upward, which displaces the lower end of the locking wall radially outward, making it easier for the locking protrusions to climb over the locked protrusions.

[0005] However, the force applied to the outer peripheral surface of the auxiliary wall to deform the top wall as described above is not necessarily small. Therefore, prior to this application, the applicant filed a patent application (Japanese Patent Application No. 2023-037358) for a container lid that can be attached to and detached from the mouth of a container without requiring a large force. The container lid disclosed in this patent application (hereinafter referred to as the "prior patent application") is composed of a cap body and an outer cap, both made of synthetic resin. The cap body includes a circular closing wall and a cylindrical skirt wall that hangs downward from the outer peripheral edge of the closing wall. A locking protrusion is formed on the outer peripheral surface of the skirt wall. A plurality of flaps extending radially outward and downward are arranged circumferentially at intervals on the underside of the skirt wall, and each of the plurality of flaps has an engaging protrusion that protrudes radially inward on its inner surface. The outer cap includes a circular top wall and a cylindrical auxiliary wall that hangs downward from the outer peripheral edge of the top wall. The inner peripheral surface of the auxiliary wall is defined by a reduced-diameter lower portion whose inner diameter corresponds to the outer diameter of the closing wall and an expanded-diameter upper portion whose inner diameter is larger than the outer diameter of the closing wall. The cap body and outer cap are molded separately and then combined. Specifically, the cap body is aligned and positioned below the outer cap, and then the cap body is forced upward relative to the outer cap, causing the locking ridges on the cap body to elastically overcome the reduced-diameter lower portion on the inner peripheral surface of the outer cap. The locking ridges overcome the reduced-diameter lower portion on the inner peripheral surface, preventing the cap body from falling off the outer cap and allowing the cap body to move freely up and down within the outer cap.

[0006] To attach the assembled container lid to the mouth of a container, the container lid is fitted onto the mouth of the container and then pushed toward it. This causes the inner surface of the cap body to abut against the outer surface of the mouth, causing the cap body to rise relative to the outer cap. As a result of this lift, the lower edge of the inner peripheral surface of the outer cap acts on the outer surface of the flap piece of the cap body, causing the flap piece to gradually pivot radially inward around its upper end, which serves as its base end. When the upper surface of the closing wall of the cap body abuts against the lower surface of the top wall of the outer cap, preventing this lift, the engaging protrusions formed on the inner surface of the flap piece are positioned below the engaging protrusions formed on the outer peripheral surface of the mouth of the container, and the cap body is held in place on the mouth of the container. Thus, the container lid is attached to the mouth of the container. Therefore, with the container lid of the prior patent application, when attaching the container lid to the mouth of a container, it is sufficient to simply fit the container lid onto the mouth of the container and then push it in; no force is required to be applied to the outer peripheral surface of the container lid.

[0007] On the other hand, when removing the container lid from the mouth of the container, the outer peripheral surface of the container lid is grasped and pulled up in the direction opposite to the direction of pushing it into the container. As a result, the cap body is lowered relative to the outer cap, and the flap piece of the cap body is released from the constraint of the reduced-diameter lower portion of the inner peripheral surface of the outer cap, and the engaging protrusion formed on the inner surface of the flap piece moves radially outward from the engaging protrusion formed on the mouth of the container. Therefore, in the container lid according to the prior patent application, when removing the container lid from the mouth of the container, it is sufficient to simply grasp the outer peripheral surface of the container lid and pull it up relative to the container, and there is no need to apply force to the outer peripheral surface of the container lid.

[0008] However, the container closures according to the above-mentioned prior patent applications are not fully satisfactory and there is room for further improvement in the following respects: Since the container closures according to the prior patent applications are constructed by combining a cap body and an outer cap that are separately molded in advance, a process of combining the separately molded cap body and outer cap is required. This process is quite complicated, which increases manufacturing costs.

[0009] The present invention was made in consideration of the above facts, and its main technical objective is to provide a new and improved synthetic resin container lid that can be attached to and detached from the mouth of a container without requiring a large amount of force, and that has a simple manufacturing process and keeps manufacturing costs down. [Means for solving the problem]

[0010] According to the present invention, a synthetic resin container lid that solves the above-mentioned main technical problem comprises a closing wall and a cylindrical skirt wall that hangs downward from the outer peripheral edge of the closing wall, An engaging protrusion is formed on the outer peripheral surface of the skirt wall, and a plurality of flaps extending downward and radially outward are arranged at intervals in the circumferential direction on the underside of the skirt wall, and an engaging protrusion protruding radially inward is formed on the inner surface of each of the plurality of flaps, A cylindrical support wall extending in the vertical direction is connected to the outer peripheral edge of the upper surface of the blocking wall or the outer peripheral surface of the skirt wall via a weakened portion, and the inner peripheral surface of the support wall is defined with a reduced diameter lower portion to which the weakened portion is connected and whose inner diameter corresponds to the outer diameter of the blocking wall, and an expanded diameter upper portion whose inner diameter is larger than the outer diameter of the blocking wall, and the reduced diameter lower portion and the expanded diameter upper portion are adjacent in the vertical direction, thereby providing a synthetic resin container lid.

[0011] Preferably, the weakened portion is connected to the lower end of the reduced diameter lower portion. The vertical length of the reduced diameter lower portion is preferably longer than the vertical length of the flap piece when the flap piece is positioned vertically. Preferably, a blocking portion is defined above the expanded diameter upper portion on the inner peripheral surface of the support wall, the blocking portion having an inner diameter equal to or smaller than the outer diameter of the closing wall. Preferably, a cylindrical extending wall is connected to the lower surface of the support wall and hanging downward, the inner diameter of the extending wall being larger than the inner diameter of the support wall. Preferably, a guide protrusion is formed at the lower end of the outer peripheral surface of the skirt wall. The weakened portions are breakable bridges arranged at intervals in the circumferential direction, and the weakened portions are preferably aligned with the flap piece in the circumferential direction. Preferably, the closing wall is formed with a protrusion that protrudes downward. An annular top wall extending radially outward is connected to the upper end of the support wall, and a cylindrical auxiliary wall hanging downward is preferably provided on the lower surface of the outer peripheral edge of the top wall. [Effects of the Invention]

[0012] A container lid constructed according to the present invention is attached to the container mouth by fitting it over the container mouth and then pushing it toward the mouth. It is removed from the container mouth by pulling it up in the opposite direction from the pushing. Therefore, a container lid constructed according to the present invention can be easily attached to the container mouth without applying any force to its outer circumferential surface, and can also be easily removed from the container mouth without applying any force to its outer circumferential surface. Furthermore, in a container lid constructed according to the present invention, the closing wall, skirt wall, and support wall are connected via weakened portions and can be molded integrally, eliminating the need for a complicated assembly process of separately molding the closing wall, skirt wall, and support wall and then assembling them. Therefore, a container lid constructed according to the present invention can be manufactured simply and at low cost. Furthermore, with a container lid constructed according to the present invention, the weakened portion can be broken during the process of attaching the lid to the mouth of a container, thereby simplifying the process of attaching the lid to the mouth of a container. With the container lid of the prior patent application, the process of attaching the container lid to the mouth of a container is carried out after the process of combining the cap body and the outer cap to form the container lid, but with a container lid constructed according to the present invention, these two processes are carried out simultaneously. This also reduces manufacturing costs using a container lid constructed according to the present invention. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a longitudinal cross-sectional view showing a preferred embodiment of a synthetic resin container lid constructed according to the present invention. [Figure 2] FIG. 2 is a bottom view of the container lid shown in FIG. 1. [Figure 3] 3A and 3B are diagrams showing a process of attaching the container lid shown in FIG. 1 to the opening of the container. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a more detailed description will be given with reference to the accompanying drawings showing preferred embodiments of a container lid constructed according to the present invention.

[0015] Referring to Figures 1 and 2, a container lid, generally designated by the numeral 2, is integrally molded by compression or injection molding from an appropriate synthetic resin. The container lid 2 comprises a circular closing wall 4 in plan view and a cylindrical skirt wall 6 that hangs downward from the outer periphery of the closing wall 4. In the illustrated embodiment, the closing wall 4 is composed of an annular outer peripheral edge portion 8, a cylindrical hanging portion 10 that hangs downward from the inner periphery of the outer peripheral edge portion 8, and a circular central portion 12 that defines the bottom surface of the hanging portion 10, with the hanging portion 10 and central portion 12 forming a protrusion 14. Therefore, the closing wall 4 has a protrusion 14 that protrudes downward. A circular abutting rib 16 extending circumferentially is formed on the underside of the outer peripheral edge portion 8 of the closing wall 4. Furthermore, a circular connecting rib 18 extending circumferentially is formed on the outer periphery of the upper surface of the closing wall 4. A locking ridge 20 is formed in the vertical middle of the outer peripheral surface of the skirt wall 6, and a guide ridge 22 is formed at the lower end. The locking ridge 20 protrudes radially outward slightly more than the guide ridge 22. Both the locking ridge 20 and the guide ridge 22 have an annular shape that extends continuously in the circumferential direction. A plurality of flaps 24 (12 in the illustrated embodiment, spaced apart circumferentially) are arranged on the underside of the skirt wall 6, extending downward and inclined radially outward. The flaps 24 are elastically pivotable in the radial direction around their base ends, i.e., their upper ends, as pivot axes. An engaging protrusion 26 that protrudes radially inward is formed on the inner surface of each of the plurality of flaps 24.

[0016] A tubular support wall 30 extending in the vertical direction is connected to the outer peripheral edge of the upper surface of the closure wall 4 via a weakened portion 28. In the illustrated embodiment, the support wall 30 is cylindrical. If desired, the support wall 30 may be connected to the outer peripheral surface of the skirt wall 6 via the weakened portion 28. In the illustrated embodiment, the weakened portion 28 connects the lower end of the inner peripheral surface of the support wall 30, i.e., the lower end of a reduced-diameter lower portion 32 (described later), to the outer peripheral surface of the connecting protrusion 18 formed on the upper surface of the closure wall 4. As shown in FIG. 2 , the weakened portions 28 are breakable bridges locally arranged at equal angular intervals in the circumferential direction and circumferentially align with the flap pieces 24. The circumferential alignment of the weakened portions 28 with the flap pieces 24 allows the molten resin to flow linearly from the weakened portions 28 to the flap pieces 24 during molding, thereby ensuring good molding of the container lid 2. Continuing the explanation mainly with reference to FIG. 1 , the inner peripheral surface of the support wall 30 is defined with a reduced-diameter lower portion 32 whose inner diameter corresponds to the outer diameter of the blocking wall 4, and an expanded-diameter upper portion 34 whose inner diameter is larger than the outer diameter of the blocking wall 4. The reduced-diameter lower portion 32 and the expanded-diameter upper portion 34 are adjacent to each other in the vertical direction. The vertical length of the reduced-diameter lower portion 32 is longer than the vertical length of the flap piece 24 when the flap piece 24 is positioned vertically (see FIG. 3(d)). A blocking portion 36 whose inner diameter is equal to or smaller than the outer diameter of the locking protrusion 20 is defined above the expanded-diameter upper portion 34 on the inner peripheral surface of the support wall 30. In the illustrated embodiment, the inner diameter of the blocking portion 36 is substantially the same as the inner diameter of the reduced-diameter lower portion 32, and the expanded-diameter upper portion 34 and the blocking portion 36 are adjacent to each other in the vertical direction. In the illustrated embodiment, the blocking portion 36 extends continuously to the upper end of the support wall 30, but if desired, it may be a circumferentially extending protrusion. A cylindrical extending wall 38 hanging downward is connected to the underside of the support wall 30. The inner diameter of the extending wall 38 is larger than the inner diameter of the support wall 30 and is not continuous with it in a straight line, but the outer diameter of the extending wall 38 is continuous with the outer diameter of the support wall 30 in a straight line in the vertical direction. A ring-shaped top wall 40 extending radially outward is connected to the upper end of the support wall 30, and a cylindrical auxiliary wall 42 hanging downward is provided on the underside of the outer peripheral edge of the top wall 40. If desired, the top wall 40 and auxiliary wall 42 may be omitted.

[0017] 3 shows the container lid 2 as well as the container mouth 100 to which the container lid 2 is attached. The container mouth 100, which can be made of a suitable synthetic resin such as polyethylene terephthalate or glass, is cylindrical overall and has an open top. An annular engaging ridge 102 that protrudes radially outward is formed at a required vertically intermediate position on the outer circumferential surface of the mouth 100.

[0018] Next, the process of attaching the container lid 2 to the container mouth 100 will be described with reference to Figure 3. When attaching the container lid 2 to the container mouth 100 after filling the container with contents such as toothpaste, first, as shown in Figure 3(a), the closing wall 4 and the skirt wall 6 are aligned above the mouth 100. Next, the container lid 2 is lowered relative to the mouth 100, and as shown in Figure 3(b), the protrusion 14 of the closing wall 4 enters the inside of the mouth 100, and the abutment ridge 16 formed on the underside of the outer peripheral edge 8 of the closing wall 4 is brought into contact with the top surface of the mouth 100. 3(b), when the container lid 2 is further lowered from the state shown in FIG. 3(b) toward the opening 100, the downward force applied to the container lid 2 during this descent acts on the weakened portion 28 through the support wall 30, causing it to break, and the support wall 30 separates from the closing wall 4 and the skirt wall 6 and descends toward the closing wall 4 and the skirt wall 6. When the support wall 30 descends from the state shown in FIG. 3(b) toward the closing wall 4 and the skirt wall 6, the locking ridges 20 and the guide ridges 22 formed on the outer peripheral surface of the skirt wall 6 are successively caused to penetrate inward from the lower end of the support wall 30. At this time, because the inner diameter of the reduced-diameter lower portion 32 of the support wall 30 corresponds to the outer diameter of the closing wall 4, the locking ridges 20 and the guide ridges 22 abut against the inner surface of the support wall 30, elastically displacing the support wall 30 radially outward, and are caused to penetrate inward of the support wall 30. At this time, the guide ribs 22 abut against the inner surface of the support wall 30, preventing the closing wall 4 and the skirt wall 6 from tilting relative to the support wall 30. FIG. 3(c) shows the state immediately after the locking ribs 20 pass through the reduced-diameter lower portion 32. In the state shown in FIG. 3(c), the lower edge of the inner circumferential surface of the support wall 30 is spaced apart from the outer surface of the flap 24. When the support wall 30 is further lowered relative to the closing wall 4 and the skirt wall 6 from the state shown in FIG. 3(c), the lower edge of the inner circumferential surface of the support wall 30 acts on the outer surface of the flap 24, gradually pivoting the flap 24 radially inward around its base end (upper end) as the pivot axis, and positioning the engaging ribs 26 formed on the inner surface of the flap 24 below the engaging ribs 102 of the mouth 100. In this way, the engaging ribs 26 restrain the engaging ribs 102.At this time, in the illustrated embodiment, the vertical length of the reduced diameter lower portion 32 is longer than the vertical length of the flap piece 24 when the flap piece 24 is positioned vertically, so that the flap piece 24 is held securely by the support wall 30, and the engaging protrusion 26 firmly restrains the engaged ridge 102. The container lid 2 is lowered relative to the container until it reaches the state shown in Figure 3(d), that is, until the locking ridge 20 abuts against the blocking portion 36 defined on the inner peripheral surface of the support wall 30, and this abutment prevents further descent.

[0019] When removing the container lid 2 from the container mouth 100, the outer peripheral surface of the container lid 2 (in the illustrated embodiment, the outer peripheral surface of the auxiliary wall 42) is grasped and forcibly raised relative to the container mouth 100. This causes the support wall 30 to rise relative to the closure wall 4 and skirt wall 6 from the state shown in FIG. 3(d) (in the illustrated embodiment, the top wall 40 and auxiliary wall 42 rise together with the support wall 30). This rise is prevented by the locking protrusion 20 formed on the outer peripheral surface of the skirt wall 6 locking with the upper end of the reduced-diameter lower portion 32 on the inner peripheral surface of the support wall 30, resulting in the state shown in FIG. 3(c). In this state, the flap piece 24 separates from the support wall 30 and tilts radially outward downward from the underside of the skirt wall 6. Therefore, the locking protrusion 26 formed on the inner surface of the flap piece 24 is not positioned below the engaged protrusion 102 of the mouth 100, releasing it. If the container lid 2 is further raised from the state shown in FIG. 3(c) relative to the mouth 100 of the container, the container lid 2 can be easily removed from the mouth 100.

[0020] The container lid 2 constructed according to the present invention is attached to the container mouth 100 by fitting it onto the container mouth 100 and then pushing it toward the container mouth 100, and is detached from the container mouth 100 by pulling it up in the opposite direction from when it was pushed into the container mouth 100. Therefore, the container lid 2 constructed according to the present invention can be easily attached to the container mouth 100 without the need to apply any force to the outer peripheral surface when attached to the container mouth 100, and can also be easily detached from the container mouth 100 without the need to apply any force to the outer peripheral surface when detached from the container mouth 100. Furthermore, in the container lid 2 constructed according to the present invention, the closing wall 4, skirt wall 6 and support wall 30 are connected via the weakened portion 28 and can be molded integrally, so there is no need for a complicated assembly process of separately molding the closing wall 4, skirt wall 6 and support wall 30 and then assembling them. Therefore, the container lid 2 constructed according to the present invention has a simple manufacturing process and reduces manufacturing costs. Furthermore, with the container lid 2 constructed according to the present invention, the weakened portion 28 can be broken during the process of attaching the container lid to the container mouth 100, which simplifies the process of attaching the container lid to the container mouth 100. With the container lid according to the prior patent application, the process of attaching the container lid to the container mouth is performed after the process of combining the cap body and the outer cap to form the container lid, but with the container lid 2 constructed according to the present invention, these two processes are performed simultaneously. This also contributes to the reduction in manufacturing costs with the container lid 2 constructed according to the present invention.

[0021] While the container closure constructed in accordance with the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiment, and appropriate modifications and changes are possible within the scope of the present invention. For example, in the illustrated embodiment, the weakened portions are bridges arranged at intervals in the circumferential direction, but if desired, they may be scores (thin walls) extending continuously in the circumferential direction. [Explanation of symbols]

[0022] 2: Container lid 4: Obstruction wall 6: Skirt wall 20: Locking ridge 24: Flap piece 26: Engagement protrusion 28: Weakened part 30: Support wall 32: Lower part of reduced diameter 34: Expanded upper part 100: (Container) Mouth 102: Engaged protrusion

Claims

1. The container includes a closing wall and a cylindrical skirt wall that hangs down from an outer peripheral edge of the closing wall, An engaging protrusion is formed on the outer peripheral surface of the skirt wall, and a plurality of flaps extending downward and radially outward are arranged at intervals in the circumferential direction on the underside of the skirt wall, and an engaging protrusion protruding radially inward is formed on the inner surface of each of the plurality of flaps, A cylindrical support wall extending in the vertical direction is connected to the outer peripheral edge of the upper surface of the blocking wall or the outer peripheral surface of the skirt wall via a weakened portion, and the inner peripheral surface of the support wall is defined by a reduced-diameter lower portion to which the weakened portion is connected and whose inner diameter corresponds to the outer diameter of the blocking wall, and an expanded-diameter upper portion whose inner diameter is larger than the outer diameter of the blocking wall, and the reduced-diameter lower portion and the expanded-diameter upper portion are adjacent in the vertical direction.

2. 2. The synthetic resin container lid according to claim 1, wherein the weakened portion is connected to the lower end of the reduced diameter lower portion.

3. 2. The male synthetic resin container lid according to claim 1, wherein the vertical length of said reduced diameter lower portion is longer than the vertical length of said flap piece when said flap piece is positioned vertically.

4. 2. The synthetic resin container lid according to claim 1, wherein a blocking portion having an inner diameter equal to or smaller than the outer diameter of the closing wall is defined above the enlarged diameter upper portion on the inner peripheral surface of the support wall.

5. 2. The synthetic resin container lid according to claim 1, wherein a cylindrical extending wall is provided on the lower surface of said support wall so as to hang down, and the inner diameter of said extending wall is larger than the inner diameter of said support wall.

6. 2. The synthetic resin container lid according to claim 1, wherein a guide ridge is formed on the lower end of the outer peripheral surface of said skirt wall.

7. 2. The synthetic resin container lid of claim 1, wherein the weakened portions are breakable bridges spaced apart in the circumferential direction, the weakened portions being circumferentially aligned with the flap pieces.

8. 2. The synthetic resin container lid according to claim 1, wherein the closing wall is formed with a protruding portion that protrudes downward.

9. A synthetic resin container lid as described in claim 1, wherein an annular top wall extending radially outward is connected to the upper end of the support wall, and a cylindrical auxiliary wall hanging downward is provided on the lower surface of the outer peripheral edge of the top wall.

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