JPH024652A - Synthetic resin container lid - Google Patents

Abstract

PURPOSE:To obtain a sufficient sealing efficiency by forming at least one ring shaped supporting protruding strap and making a contact pressure between the end surface of a container mounth and a packing member increase locally at the position where the ring shaped supporting protruding strap exists. CONSTITUTION:A container lid is equipped with a container lid main body 2, which has a ceiling wall 4 and a cylindrical shaped skirt wall 6 vertically hanging from the peripheral edge of the ceiling wall, and a packing member 30, which has been arranged on the inner surface of the ceiling wall. The container lid main body 2 is made of a comparatively hard synthetic resin material, and the packing member 30 is made of a comparatively soft synthetic resin material. At a ring shaped peripheral edge region on the inner surface of the ceiling wall of the container lid main body 2, which confronts the end surface of a mouth part 38, ring shaped supporting protruding straps 48, 50 have been formed, and a contact pressure between the end surface of the mouth part 38 and the packing member 30 is locally increased at the position where the ring shaped supporting protruding straps 48, 50 exist.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a synthetic resin container lid.

[Prior art and its drawbacks]

For example, in synthetic resin container lids having pilfer-proof properties as disclosed in JP-A No. 56-74445, and in various other forms of synthetic resin container lids,
As is well known to those skilled in the art, to increase sealing,
In addition to the container lid body having a top wall and a skirt wall depending from the periphery of the top wall, a synthetic resin material separate from the container lid body, generally a synthetic resin material softer than the synthetic resin material forming the container lid body. It is often desirable to dispose a packing member formed from the above on the inner surface of the top wall of the container lid body.

However, in conventional synthetic resin container lids of the type provided with the above-mentioned packing, there is a problem in that the sealing performance cannot always be sufficiently increased, as will be explained in detail later.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned facts, and its main purpose is to provide an improved container lid that is made of synthetic resin and is equipped with the above-mentioned packing member, and is capable of achieving sufficient sealing performance. It is to provide.

[Summary of the invention]

According to the present invention, the container lid main body includes a top wall and a cylindrical skirt wall hanging from the periphery of the top wall, and a packing member disposed on the inner surface of the top wall of the container lid main body, In a synthetic resin container lid of the type in which the container lid body is formed from a relatively hard synthetic resin material and the packing member is formed from a relatively soft synthetic resin material; At least one patchy support ridge is formed in the annular peripheral region opposite to the end face of the neck of the container, and the contact pressure between the end face of the mouth and neck and the packing member is A container lid is provided which is characterized in that the support ridges are locally enlarged in the region where they are present.

[Specific examples of the invention]

Further details will be given below with reference to the accompanying drawings.

FIG. 1 illustrates a specific example of a synthetic resin container lid improved according to the present invention. In the illustrated specific example, the present invention will be explained as being applied to a container having pilfer-proof properties, but it can be similarly applied to other types of container lids.

The container lid illustrated in FIG. 1 includes a container lid body generally designated by the number 2. The container lid main body 2, which can be formed by injection molding or embossing (compression) molding, has a circular top wall 4 and a substantially cylindrical skirt wall 6 depending from the periphery of the top wall 4.

A breaking line 8 extending in the circumferential direction is formed in the skirt wall 6, and the breaking line 8 allows the skirt wall 6 to
is divided into a main part 10 above the break line 8 and a pilfer-proof hem part 12 below the break line 8. The fracture line 8 is composed of a plurality of slits (cut grooves) 14 that are formed at intervals in the circumferential direction and extend in the circumferential direction, and a plurality of bridge portions 16 that remain between the slits 14. ing. The pilfer-proof hem portion 12 is connected to the main portion 1o by a plurality of bridging portions 16.

A female thread 18 is formed on the inner surface of the main portion 10 of the skirt wall 6. Further, the outer surface of the main portion 10 is formed with an uneven shape or a knurled shape 20 to prevent the fingers from slipping when rotating the container lid by placing the fingers thereon.

On the other hand, the pilfer-proof hem 12 of the skirt wall 6 is
In the illustrated example, the outer surface thereof is formed into a curved surface that gradually projects outwardly toward the bottom, and the wall thickness gradually increases toward the bottom. A plurality of locking flap pieces 22 are formed on the inner surface of the pilfer-proof hem 12 at intervals in the circumferential direction. Each of the locking flap pieces 22 projects radially inward from a base edge 24 connected to the inner surface of the pilfer-proof hem 12 . In the illustrated embodiment, as clearly shown in FIG. 2, the base edge 24 of each of the locking flap pieces 22 is attached to the container lid when the container lid is attached to the neck of the container, as will be described below. Rotation direction (clockwise when viewed from above in Figure 1)
It extends downward in the opposite direction (counterclockwise when viewed from above in FIG. 1) and at an acute angle α with respect to the axial direction. In addition, each of the locking flap pieces 22 is
The above rotation direction (clockwise when viewed from above in Figure 1)
The base edges 24 are inclined in the opposite direction (counterclockwise when viewed from above in FIG. 1) and protrude radially inward from each base edge 24. The locking flap piece 22 itself has a substantially triangular shape, and its upper edge 26 extends downwardly at a slight angle β and extends radially inward, and its lower edge 28 extends upwardly at a corresponding angle β. and extends radially inwardly at an angle T of, for example, 60 degrees. The angle β is such that the locking flap piece 22 is elastically deflected along its base edge 24 in the opposite direction (counterclockwise in FIG. 1) with respect to the rotational direction (clockwise in FIG. 1). Then, the locking flap piece 22
Advantageously, the upper edge 26 is set to be substantially horizontal when one side of the pilfer-proof hem 12 is in contact with the inner surface of the pilfer-proof hem 12.

In addition to the container lid body 2 described above, the illustrated container lid further includes a packing member 30 disposed on the inner surface of the top wall 4 of the container lid body 2. Such a packing member 30
is formed from a synthetic resin material different from the synthetic resin material forming the container lid body 2. When the container lid body 2 and the packing member 30 are formed from separate synthetic resin materials, the container lid body 2 is formed from a relatively hard synthetic resin material such as polypropylene or hard polyethylene,
Packing member 30 is conveniently formed from a relatively soft synthetic resin material such as polyvinyl chloride, ethylene vinyl acetate or flexible polyethylene.

Packing member 30 in the illustrated embodiment is generally disc-shaped and has a substantially flat underside. On the other hand, the container lid body 2
The inner surface of the top wall 4 has a disk-shaped protrusion 31 in its central circular area, and therefore its annular peripheral area is recessed. The upper surface of the packing member 30 is matched with the inner surface of the top wall 4 of the container lid body 2, and therefore the thickness of the packing member 30 is increased in its annular peripheral region. Such a packing member 30
This can be conveniently done by, for example, loading a synthetic resin material in a heated and molten state onto the inner surface of the top wall 4 of the container lid body 2 that has already been formed, and then pressing (compression) molding the synthetic resin material into the desired shape. can be formed into

A container closure as described above is applied to a container with a conventional neck as shown at 38 in FIG. The mouth and neck portion 38 having an open upper end has a substantially cylindrical shape, and a male thread 40 and a locking flange 42 located below the male thread 40 are formed on its outer peripheral surface. The circumferential side surface of the locking flange 42 is inclined downwardly and outward in the radial direction, and an annular locking surface 44 that is actually horizontal when purchased is defined on the lower surface of the locking flange 42 .

To seal the mouth and neck part 38 by attaching the container lid to the mouth and neck part 38, the container lid is fitted onto the mouth part 38 and the container lid is rotated clockwise when viewed from above in FIG. In this way, the female thread 18 formed on the container lid is screwed into the male thread 40 formed on the mouth portion 38, thereby causing the container lid to move downward in the axial direction as it rotates. When the container lid is moved downward, the locking flap piece 22 formed on the container lid passes through the male thread 40 formed in the mouth portion 38 and then through the locking flange 42. However, at this time, the locking flap piece 22 is elastically bent counterclockwise when viewed from above in FIGS. 1 and 3 under the action of the locking flange 42, thus causing the container lid to move downward. Depending on the movement, the locking flap piece 22 can pass through the locking flange 42. When the female thread 18 of the container lid and the male thread 40 of the neck part 38 are fully screwed together and the container lid is fully attached to the neck part 38, as shown in FIG. It completely passes through the locking flange 42 and is no longer affected by the locking flange 42,
It returns to its original state elastically.

Thus, when the upper edge 26 of the locking flap piece 22 is locked to the annular locking surface 44 defined on the lower surface of the locking flange 42, and when the container lid is fully attached to the neck portion 38, Packing member 30 as shown in FIG.
The lower peripheral edge of the mouth portion 38 is brought into close contact with the end surface 46 of the mouth portion 38, thus sealing the mouth portion 38.

When the container lid attached to the mouth and neck part 38 as described above is removed from the mouth part 38 and the mouth and neck part 38 is opened, the container lid is rotated in the opposite direction to the direction of rotation when the container lid is attached, that is, in the third direction. When the container lid is rotated counterclockwise when viewed from above in the figure, the female thread 18 formed on the container lid is moved along the male thread 40 formed on the mouth portion 38, so that the container lid is rotated counterclockwise. is going to move upward in the axial direction. However, the pilfer-proof hem of the container lid 1
Upper edge 2 of the locking flap piece 22 disposed on the inner surface of 2
6 is locked to the annular locking surface 44 defined on the lower surface of the locking flange 42 of the mouth and neck portion 38, the pilfer-proof hem B12 is prevented from moving upward in the axial direction. Significant stresses are thus created in each of the bridges 16 (or 216) at the break line 8 formed in the container lid, connecting the pilfer-proof skirt 12 to the main portion 10 of the skirt wall 6. Bridge section 16 (or 21
6) is broken.

In the example container lid, as described above, each of the locking flap pieces 22 is disposed in association with each of the bridges 16 at the break line 8, and as clearly illustrated in FIG. The upper end of the base edge 24 of each locking flap piece 22 is substantially aligned with each of the bridges 16 when viewed in the axial direction. In other words, the upper end of each base edge 24 of the locking flap piece 22 is located at the bridge portion 16 at the breaking line 8.
are located directly below each of them in the axial direction. Therefore, the second
As will be readily understood by referring to FIG. 3 in conjunction with the drawings, the force that prevents axial upward movement of the pilfer-proof hem 12 from the annular locking surface 44 of the locking flange 42 to the locking flap The force applied to the upper edge 26 of the piece 22 is transmitted directly to the bridge 16 and therefore breaks the bridge 16 reliably and with sufficient ease.

When the bridge R16 at the break line 8 is broken, the pilfer-proof hem 12 is separated from the main part 10 of the skirt wall 6. After that, the portion of the container lid other than the pilfer-proof hem 12 can easily move upward in the axial direction, and therefore moves upward in the axial direction in response to the rotation of the container lid to separate from the neck portion 38. It is removed, and the mouth and neck region 38 is thus opened. On the other hand, the pilfer-proof hem 12 remains there without being separated from the mouth and neck region 38.

The container lid of the specific example is further configured as follows in order to improve the sealing performance of the packing member 3°.

Referring to FIG. 4 together with FIG. 4, two annular support protrusions are provided in the annular peripheral area on the inner surface of the top wall 4 of the container lid body 2, that is, in the annular peripheral area opposite to the end surface 46 of the neck part 38.
That is, an outer annular support ridge 48 and an inner annular support ridge 50 are formed. The outer annular support ridge 48 is located opposite to the outer periphery of the end surface 46 of the mouth and neck portion 38 , and the inner annular support ridge 50 is located opposite to the inner periphery of the end surface 46 of the mouth portion 38 . Due to the presence of the outer annular support ridge 48 and the inner annular support ridge 50, the packing member 3
0, the wall thickness is locally reduced in two annular regions (ie, the region where the outer annular support ridge 48 and the inner annular support ridge 50 are present).

The container lid configured as described above has an outer annular support ridge 4.
8 and an inner annular support ridge 5o are not provided, the container lid has the following advantages. In the conventional container lid, as is easily understood, the contact pressure between the lower surface of the packing member 3o and the end surface 46 of the neck portion 38 is constant over the entire area from the inner circumferential edge to the outer circumferential edge of the end surface 46 of the neck portion 38. It is about average. Therefore, the pressure applied from the container lid to the end surface 46 of the neck section 38 is distributed approximately evenly over the entire area of the end surface 46 of the neck section 38. On the other hand, the fourth
In the container lid shown partially enlarged in the figure, the outer annular support ridge 48 and the inner annular support ridge 50 are made of 2
In these annular regions, the contact pressure between the lower surface of the packing member 30 and the end surface 46 of the mouth portion 38 becomes locally high. To elaborate further on this point, as already mentioned, in general,
The container lid body 2 is formed from a relatively hard synthetic resin material, and the packing member 30 is formed from a relatively soft synthetic resin material. Therefore, the lower surface of the packing member 30 is brought into close contact with the end surface 46 of the neck portion 38, and the packing member 3
0 is elastically compressed between the top wall 4 of the container lid main body 2 and the end surface of the mouth portion 38, the outer annular support ridge 48 and the inner side formed of a relatively hard synthetic resin material The annular support ridge 50 locally backs up the packing member 30, and thus the packing member 30 has the outer annular support ridge 48 and the inner annular support ridge 50 present.
The annular regions, that is, the outer circumference and inner circumference of the end surface 46 of the mouth and neck portion 38 are locally strongly brought into close contact with the end surface 46 of the mouth and neck portion 38 . In this way, the lower surface of the packing member 30 and the mouth and neck part 3
When the contact pressure with the end surface 46 of the mouth portion 38 is locally increased in a predetermined annular region, the pressure applied from the container lid to the end surface 46 of the mouth portion 38 is concentrated in the predetermined annular region, and A considerable contact pressure is generated in the annular region of the container, thus increasing the sealing performance of the neck part 38 by the packing member 3o. Sufficient sealing performance can be obtained even when the sealant is formed.

FIG. 5 shows a modification of the container lid according to the invention. In this modification, in addition to the above-described outer annular support ridge 48 and inner annular support ridge 50 being formed on the inner surface of the top wall 4 of the container lid body 2, The peripheral side wall surface of the disc-shaped protrusion 310 existing in the central region of the inner surface is projected toward the inner peripheral edge of the end surface 46 of the mouth and neck portion 38, as indicated by reference numeral 52. In such a modification, the outer annular support ridge 48 and the inner annular support ridge 50
two annular regions corresponding to the end face 46 of the mouth portion 38;
In addition to the outer and inner circumferential parts of the packing member 30 and the inner circumferential edge of the end face 46 of the mouth and neck part 38 due to the protrusion of the circumferential wall surface of the disc-shaped protruding part 31, the lower face of the packing member 30 and the mouth part 38 are End face 4
6 is locally increased.

[Brief explanation of the drawing]

FIG. 1 is a side view, partially in cross section, of an example of a synthetic resin container lid having improved pilfer-proof properties according to the present invention. 2 is a perspective view showing a part of the container lid of FIG. 1; FIG. 3 is a side view partially showing the state in which the container lid of FIG. 1 is fitted over the mouth and neck of the container; FIG. FIG. 4 is an enlarged cross-sectional view of a part of the state shown in FIG. 3; FIG. 5 is a partially enlarged sectional view showing a modified example of the container lid fitted into the mouth and neck of the container. 2... Container lid body 4... Top wall 6... Skirt wall 8... Fracture line 30... Packing member 38... Mouth and neck portion 48... Outer annular support ridge 50... Inner annular support ridge Patent applicant: Japan Crown Cork Co., Ltd. Figure 1 Figure 2 34N

Claims (1)

[Claims] 1. A container lid body having a top wall and a cylindrical skirt wall hanging from the periphery of the top wall, and a packing member disposed on the inner surface of the top wall of the container lid body. In a synthetic resin container lid of the type in which the container lid body is formed from a relatively hard synthetic resin material and the packing member is formed from a relatively soft synthetic resin material; At least one annular supporting protrusion is formed in an annular peripheral region facing the end face of the mouth and neck of the container on the inner surface of the face wall, and the contact pressure between the end face of the mouth and neck and the packing member is A container lid characterized in that the support ridges are locally enlarged in the region where they are present. 2. The device according to claim 1, wherein an outer patchy support ridge facing the outer periphery of the end face of the mouth and neck and an inner annular support ridge facing the inner periphery of the end face of the mouth and neck are formed. container lid. 3. A disc-shaped protrusion is formed in a central region of the inner surface of the top wall of the container lid body, radially inward from the inner periphery of the end face of the mouth and neck, and the circumference of the disc-shaped protrusion is The side wall surface is made to protrude toward the inner periphery of the end face of the mouth and neck, whereby the contact pressure between the end face of the mouth and neck and the packing member is locally increased also at the inner periphery of the end face of the mouth and neck. A container lid according to claim 1 or 2.