JP7542178B2 - Cap Unit - Google Patents

Description

The present invention relates to a cap unit that is attached to the mouth of a can used for transporting or storing food, paint, chemicals, fuel oil, and the like.

An example of a conventional cap unit is disclosed in Japanese Patent Application Laid-Open No. 2003-233999, in which a resin packing is housed in a metal cap with an elastic hook.

The cap with elastic hook of this cap unit has a top wall that can be freely raised and lowered, and a side wall formed of multiple elastic hooks, and when the top wall is pressed to raise and lower, the elastic hooks on the side wall open and close in conjunction with this. The cap is attached to the can mouth with the elastic hooks closed, and when attached, the tip of the elastic hook is elastically engaged with the upper inclined part of the recess in the side wall of the can mouth, and at the same time, the peripheral part of the resin packing housed in the elastic hook cap is sandwiched from above and below between the upper end of the can mouth and the outer periphery of the upper surface of the cap with elastic hooks, so that it is pressurized and tightly adheres to the can mouth, sealing the can mouth to prevent the contents from leaking.

However, in the cap unit of Patent Document 1, when the can mouth is attached, the sharp tip of the elastic hook slides along the upper arc of the can mouth while making contact with the can mouth's side wall recess, causing the varnish or laminate film applied to the can mouth to prevent rust to be scraped off, causing problems such as the peeled off pieces getting mixed into the can contents or the can mouth becoming rusty. There is also a risk of the sharp tip of the elastic hook injuring fingers, etc.

In the cap units disclosed in Patent Documents 2 and 3, the resin packing is provided with a peripheral portion for contacting the can mouth, an arc-shaped flange portion extending outward from the outer periphery of the peripheral portion, a hanging portion extending downward from the lower end of the flange portion, and an outer portion extending outward from the lower end of the hanging portion, and the tip of the elastic hook-fastening piece in the closed state is covered by the hanging portion and the outer portion, thereby preventing the sharp tip of the elastic hook-fastening piece from directly contacting the can mouth, thereby solving the above problem. Also, the resin packing is provided with many open slits all around from the hanging portion to the outer portion, so that the diameter of the part where the tip of the elastic hook-fastening piece is engaged can change without excessive deformation in conjunction with the opening and closing movement of the elastic hook-fastening piece.

Japanese Utility Model Application Publication No. 60-148261 (see Figure 2) Patent Publication No. 4174717 (see Figure 7) Japanese Patent No. 5376176 (see Figure 2)

However, the cap units of Patent Documents 2 and 3 have a drawback in that the resin packing covering the tip of the elastic hook has many slits that are open even when the cap unit is attached to the can mouth, so if the cap unit is attached when there is liquid such as soy sauce on the can mouth, the liquid easily passes through the slits and adheres to the elastic hook. If liquid adheres to a metal cap with an elastic hook, rust will occur, making it dirty, and there is also a risk that the rust liquid will get into the can contents.

The main times that liquid adheres to a can mouth are when it adheres unintentionally when filling the can with soy sauce or other liquid, or when the user pours the contents of the can out of the mouth. In either case, however, there are frequent cases where the cap unit is attached (or reattached) to the can mouth without thoroughly wiping off the adhered liquid, causing the elastic hook-and-loop cap to rust, so preventing this rust has been a long-standing issue.

Therefore, an object of the present invention is to provide a cap unit which prevents the varnish from peeling off from the can mouth at the lower end of the elastic hook-and-loop piece and scratches on fingers, etc., and which prevents or reduces rust on the elastic hook-and-loop piece.

In order to achieve the above object, the cap unit according to the present invention includes the following aspects.

<1> A cap unit comprising a cap with elastic hooks, the cap having a top wall that can be freely raised and lowered, and a side wall formed of a plurality of elastic hooks that open and close by pressing the top wall, and a resin packing having a packing body, a can mouth abutment part for tightly contacting the top of the can mouth, the flange part extending outward from the outer periphery of the can mouth abutment part, and a hanging part extending downward from the flange part, the resin packing having a hanging part extending to the lower end of the opening of the imaginary cylinder with a top that virtually covers the open gaps between adjacent elastic hooks and has a nearly circular opening lower end surface that is flush with the fractured surfaces of the tips of the elastic hooks, the hanging part of the resin packing of the cap unit extends to the lower end of the opening of the imaginary cylinder with a top. When the cap unit is attached to the can mouth, from the time when this outer part abuts the upper arc portion of the can mouth and descends along the upper arc portion of the can mouth while widening the inner diameter of the lower end of the hanging part, until it enters the side wall recess of the can mouth and engages, and while it is attached to the can mouth, the side inner wall of the imaginary approximately topped cylinder is covered over its entire circumference by the hanging part, the brim portion and the can mouth abutment portion, and the open lower end surface of the imaginary approximately topped cylinder is also maintained in a state where it is covered over its entire circumference by the outer part.

In the manufacturing process of the cap with elastic hook, a metal plate (mainly tinplate) is punched into a petal shape by a press to form the outer edge, but when tinplate is used, the broken surface has exposed iron. In other words, the broken surface of the side groove of the elastic hook and the broken surface of the tip are particularly susceptible to rust. According to the above-mentioned configuration <1>, when the elastic hook is attached to the can mouth and between the capping and when the elastic hook is attached to the can mouth, the broken surface of the side groove and the broken surface of the tip are completely covered with respect to the can mouth by the hanging part, the flange part, the can mouth abutting part and the outer part of the resin packing, so that even if the cap unit is attached to the can mouth with liquid still attached to the upper circular arc part of the can mouth or the side wall recess, the liquid will not adhere to the broken surface that is susceptible to rust. In addition, since the sharp tip of the elastic hook is covered by the outer part of the resin packing, there is no risk of damaging the can mouth.

Furthermore, in the conventional cap units of Patent Documents 2 and 3, unless the position of the groove in the elastic hook piece is matched with the position of the open slit in the plastic packing, the fractured surface of the side groove with the elastic hook piece and the fractured surface of the tip are exposed, making it easier for liquid to adhere to the fractured surface and causing injury to fingers, etc. However, according to the configuration of <1> above, when the capping is between the capping and when it is attached to the can mouth, the side inner wall and the fractured surface of the tip of the elastic hook piece, including the open gap between adjacent elastic hook pieces, are completely covered by the hanging part, brim part, can mouth abutment part and outer part of the plastic packing against the can mouth over the entire circumferential surface, including the open gap between adjacent elastic hook pieces, so that it is effective in preventing liquid from adhering and fingers from being injured, regardless of the rotational position of the plastic packing relative to the position of the groove in the elastic hook piece.

In the first place, in the conventional cap units of Patent Documents 2 and 3, even if the position of the groove of the elastic hook is matched with the position of the open slit of the resin packing, liquid adhering to the upper circular arc portion of the can mouth or the recessed portion of the side wall passes through the open slit and seeps out to the fracture surface of the tip of the elastic hook, the fracture surface of the side groove, and the side inner wall, leading to dirt and rusting of the elastic hook. According to the configuration of <1> above, when the capping is in the state where it is attached to the can mouth, the open gap between the side inner wall of the elastic hook and the adjacent elastic hook is completely covered with the entire circumference against the can mouth by the hanging part, the flange part, and the can mouth abutment part of the resin packing, so there is no risk of liquid slipping through and adhering. In addition, since there is no open slit in the resin packing, even if rust occurs in the elastic hook, there is no risk of the rust liquid passing through the open slit and mixing with the can contents.

<2> Preferably, before the plastic packing is stored in the cap with elastic hook-and-loop fastening piece, the plastic packing is molded as a single, connected piece with no open gaps or notches around the entire circumference, from the can mouth abutment part to the flange part, from the flange part to the hanging part, and from the hanging part to the outer part, to a length that will completely cover the opening lower end face of the imaginary approximately top-open cylinder when the plastic packing is later stored in the cap with elastic hook-and-loop fastening piece.

According to the above configuration <2>, for example, there is a gap from the hanging part of the resin packing to the outer end of the outer part, but unlike cap units in which the gap is sealed tightly when the resin packing is stored in a cap with an elastic hook to form a cap unit, there is not even a sealed seam, so there is no room for liquid to seep through the seam and adhere to the elastic hook, and a greater rust prevention effect can be expected.

In particular, when the plastic packing remains on the can mouth because it has become familiar with the can mouth when the cap unit is removed from the can mouth, in order to close the can mouth again, the plastic packing is removed from the can mouth, stored in the cap with elastic hook, and the cap unit is attached to the can mouth again. During this process, if there is a seam in the part of the plastic packing covering the elastic hook, the contact position and contact force of that part may change, causing liquid to seep out, or liquid on fingers may adhere to the tip of the cap with elastic hook when the fractured surface of the tip of the cap with elastic hook is exposed through the gap in the plastic packing, which may lead to dirt or rust. According to the configuration of <2> above, even when the cap unit is reassembled, there is no seam in the part of the plastic packing covering the elastic hook, and there is no time when the fractured surface of the tip of the elastic hook is exposed from the outer part of the plastic packing, so there is no need to worry about this.

<3> More preferably, the hanging portion and the outer portion of the resin packing share a plurality of thin slit membrane portions that are thinner than the surroundings, and the thin slit membrane portions are arranged radially. In addition, the thin slit membrane portions extend from the hanging portion to the outer end of the outer portion in the radial direction of the radial line along which the thin slit membrane portions are arranged.

When the resin packing is tensioned against the cap with elastic hooks as in the cap unit of Patent Document 3, the diameter of the lower end of the hanging part of the resin packing changes before and after it is stored in the cap with elastic hooks to form a cap unit. The circumferential length of the lower end of the hanging part becomes shorter after it is formed into a cap unit, but if the hanging part and the outer part are connected while maintaining a uniform thickness over the entire circumference, the hanging part and the outer part will not be folded evenly over the entire circumference, and excessive force may be applied, causing deformation to the brim part, etc. According to the configuration of <3> above, since a thin slit membrane part is partially provided from the hanging part to the outer part, when the resin packing is stored in the cap with elastic hooks to form a cap unit, the thin slit membrane part, which is easily deformed, is folded first, and distortion due to excessive deformation is unlikely to occur. In addition, by arranging the thin slit membrane part partially rather than over the entire circumference, it is possible to maintain a strength that does not easily collapse. In other words, the diameter of the lower end and outer part of the hanging part can be smoothly changed in conjunction with the opening and closing of the elastic hook piece.

Even if the thin slit membrane portion tears during the capping process, the torn parts overlap when the cap is attached to the can mouth and between the caps, so that the elastic hook-stop pieces and the open gaps between adjacent elastic hook-stop pieces are completely covered by the can mouth, making it difficult for liquid to adhere to the elastic hook-stop pieces.

In the cap units of Patent Documents 2 and 3, the folds are divided by an open slit from the hanging part to the outer end of the resin packing, so that each divided fold can easily rotate independently, and when the cap unit is assembled again or when it is attached to the can mouth, the part covering the tip of the elastic hook of the resin packing (outside the lower end of the hanging part) may bend inward, resulting in the appearance of a fold that enters the inside of the elastic hook. According to the configuration of <3> above, the folds divided by the thin slit membrane part are connected to the adjacent folds by the thin slit membrane part, so that they are difficult to rotate independently, and as a result, the folds are difficult to bend inward. Even if the folds bend inward, the thin slit membrane part beside the bent fold breaks, so that the fold can be noticed by the feeling of the break, and another cap unit can be reattached.

<4> In the cap unit described in any one of <1> to <3> above, at least one of the following is applied: the outer part of the resin packing has an outer corner cover part that covers the corner where the opening lower end face of the imaginary approximately topless cylinder intersects with the outer wall around the entire circumference, or extends outward until it covers a width that is 1.5 times or more the width of the opening lower end face of the imaginary approximately topless cylinder.

According to the above configuration <4>, liquid is less likely to adhere to the fractured surface at the tip of the elastic hook piece, which is prone to rust, and the rust prevention effect can be further improved.

As described above, according to the present invention, a cap unit can be provided which prevents the varnish from peeling off of the can mouth and scratches on fingers at the lower end of the elastic hook-and-loop piece, and also prevents and reduces rust on the elastic hook-and-loop piece.

1 is a cross-sectional view of a cap unit according to an embodiment of the present invention (first embodiment). 2 is a cross-sectional view showing a state in which the cap unit of FIG. 1 is attached to a can mouth. FIG. 3 is an enlarged view of an area A surrounded by a dashed line in FIG. 2 . 2A, 2B, and 2C are diagrams showing a resin packing used in the cap unit of FIG. 1, in which FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. This is a cross-sectional view taken along line B-B of FIG. In FIG. 4C, an enlarged perspective view of an area C surrounded by a dashed line, the shaded area is a thin slit membrane portion. FIG. 11 is a cross-sectional view of a cap unit according to an embodiment of the present invention (second embodiment). 1A and 1B are diagrams showing the cap with an elastic hook and the imaginary cylinder with a top according to the first and second embodiments, in which (d) is a front view of the cap with an elastic hook, (e) is a bottom view of the cap with an elastic hook, (f) is a front view of the imaginary cylinder with a top, and (g) is the imaginary cylinder with a top. The shaded areas are views showing some of the variations in the end face taken along line D-D in FIG. 4(c), and the dotted areas are views showing some of the variations in the end face taken along line E-E in FIG. 4(c). ((i) to (vi)) ((i) is the first embodiment) The shaded areas are views showing some of the variations in the end face taken along line D-D in FIG. 4(c), and the dotted areas are views showing some of the variations in the end face taken along line E-E in FIG. 4(c). ((vii) to (ix)) These are schematic diagrams showing some of the variations in the end faces along the lines F-F and G-G in Figure 6. The upper figures show the state before the resin packing is stored in the elastic hook-and-loop cap, and the lower figures show the state after it is stored and the gap between the thick portions (folds) is reduced. ((I) to (V)) ((I) is the first embodiment)

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 6 and 8. FIG.

First, the configuration of the cap unit in the first embodiment will be described (see FIG. 1). The cap unit 1 in the first embodiment includes a cap 11A with an elastic hook, a resin packing 10, and a sealing member 12. The resin packing 10 is housed in the cap 11A with an elastic hook, and the cap 11A with an elastic hook is further housed in the sealing member 12.

The cap with elastic hook 11A is made of a single tinplate and has a top wall 110 that can be freely raised and lowered, and a number of elastic hook pieces 111A provided at equal intervals on the side wall. The elastic hook pieces 111A are opened and closed in conjunction with the top wall 110 by pressing it. The outer edge of the cap with elastic hook 11A is punched out by a press during manufacturing, so the fractured surface 112A at the tip of the elastic hook piece and the fractured surface 114 of the side groove of the cap with elastic hook have exposed iron and are prone to rust.

Figures 8 (f) and (g) show a virtual approximately top-open cylinder 11B that virtually blocks the side groove 113 (the open gap between adjacent elastic hook pieces) of the elastic hook cap 11A and has an approximately circular opening lower end surface 112B that is flush with the fracture surface 112A at the tip of the elastic hook piece.

The resin packing 10 is made of elastic polyethylene, and is integrally molded by injection molding including a packing main body 100, a can mouth abutment portion 101 for tightly contacting the upper end of the can mouth and located annularly around the outer periphery of the packing main body 100, a flange portion 102 extending outward from the outer periphery of the can mouth abutment portion 101, a hanging portion 103 extending downward from the flange portion 102, and an outer portion 104 extending outward from the lower end of the hanging portion 103.

The packing body 100 is composed of a flat portion 100a, an annular protrusion 100b provided in the middle of the flat portion 100a, and a conical expansion portion 100c extending upward and outward from the outermost periphery of the flat portion 100a. The annular protrusion 100b supplements the strength of the flat portion 100a, and when the pressure inside the can increases, the outer inclined portion of the annular protrusion 100b pushes the conical expansion portion 100c outward via the outer periphery of the flat portion 100a, strengthening the adhesion to the inner diameter of the mouth of the can mouth 2 and improving airtightness.

The can mouth abutment portion 101 is formed continuously from the upper end of the conical expansion portion 100c, and has a thick-walled portion 101a which is a base with a gap between it and the conical expansion portion 100c, and an outer rising portion 101b which extends downward and outward from the lower surface of the outer periphery of the thick-walled portion 101a. When the cap unit 1 is attached to the can mouth 2, the can mouth abutment portion 101 is sandwiched and closely attached from above and below between the outer periphery of the upper surface of the elastic hook-and-loop cap 11A and the upper part of the can mouth upper arc portion 20, thereby maintaining airtightness between them. In addition, the conical expansion portion 100c and the outer rising portion 101b are formed in an inverted V shape with respect to the upper part of the can mouth upper arc portion 20, and are abutted at two points, the inside and the outside, of the upper part of the can mouth upper arc portion 20 to maintain airtightness.

The flange 102 is formed by extending outwardly downward in an arc shape from the lower outer periphery of the thick wall portion 101a of the can mouth abutment portion. The outer diameter of the flange 102 of the resin packing 10 before being stored in the cap 11A with elastic hook is set to be slightly larger than the maximum inner diameter of the elastic hook 111A in the open state. By doing so, when the resin packing 10 is stored in the cap 11A with elastic hook, the tip of the elastic hook 111A in the open state first abuts against the flange 102. When the resin packing 10 is further pressed in, the tip of the elastic hook 111A is guided along the arc-shaped flange 102 while maintaining the abutment state, so that the storage can be performed stably. Furthermore, when the cap unit 1 is removed from the can mouth 2, the flange 102 is taut with respect to the cap 11A with elastic hooks in the open state of the elastic hook pieces 111A, so that the resin packing 10 is less likely to fall off. When stored in the cap 11A with elastic hook pieces, the flange 102 deforms inward, and since there is a gap between the thick-walled portion 101a and the conical expansion portion 100c, the outer rising portion 101b is pushed inward together with the thick-walled portion 10a, which also functions to improve adhesion to the outside of the upper part of the upper arcuate portion 20 of the can mouth.

The hanging portion 103 is formed by continuously extending downward from the flange portion 102. Also, the hanging portion 103 partially has a thin-walled slit membrane portion 105a formed with a thinner wall than the surrounding area. When the resin packing 10 is stored in the elastic hook-attached cap 11A, the entire circumference of the hanging portion 103 extends to the lower end of the opening of the imaginary substantially topped cylinder 11B. As a result, the inner surface of the imaginary substantially topped cylinder side wall 111B is covered over the entire circumference by the hanging portion 103, the flange portion 102, and the can mouth abutment portion 101, so that liquid is less likely to adhere to the fracture surface 114 of the side groove of the elastic hook-attached cap, which is prone to rust, and rust is prevented.

The diameter of the lower end of the hanging part 103 of the resin packing 10 before being stored in the cap 11A with elastic hook (the diameter of the part where the tip of the elastic hook 111A is later locked) is set to be larger than the inner diameter of the tip of the elastic hook 111A in the open state. This ensures that the elastic hook 111A is always kept in a taut state, the tip of the elastic hook 111A is stably locked, and the outer part 104 is less likely to get inside the elastic hook 111A. Also, when the resin packing 10 is pushed in to be stored in the cap 11A with elastic hook, the tip of the elastic hook 111A in the open state is guided to the part where the tip of the elastic hook 111A is finally locked while maintaining a state of abutment from the flange 102 to the lower end of the hanging part 103, so that the storage can be performed stably.

The outer portion 104 has an outward extending portion 104a extending outwardly continuously from the lower end of the hanging portion 103, an outer corner cover portion 104b extending upward from the outward extending portion 104a to cover the corner where the opening lower end surface 112B of the imaginary approximately topless cylinder intersects with the outer wall of the imaginary approximately topless cylinder side wall 11B, and an outer rising portion 104c extending upward from the outer end of the outward extending portion 104a. The outer portion 104 also has, as a part thereof, thin-walled slit membrane portions 105b, 105c formed with a thinner wall than the surrounding area.

When the resin packing 10 is housed in the elastic hook-attached cap 11A, the outer part 104 has an outer corner cover part 104b (including 105c) over the entire circumference. In the thick part that is not the thin slit membrane part 105, the outer part 104 is extended to a length that covers 6.2 times the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top cylinder. It is desirable that at least one of the following is applied: the outer part 104 has an outer corner cover part 104b over the entire circumference, or the outer part 104 is extended to a length that covers 1.5 times the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top cylinder. This makes it more difficult for liquid to adhere to the fracture surface 112A at the tip of the elastic hook-attached piece, which is prone to rust, and rust is prevented. Furthermore, regardless of the rotational position of the side groove 113 of the cap with the elastic hook, the fracture surface 112A at the tip of the elastic hook is entirely covered, preventing scratches on the can mouth 2, fingers, etc.

The outward extension 104a has a bottom surface with an inclined surface that becomes lower as it goes outward when the resin packing 10 is stored in the cap 11A with elastic hook. Even if the central axis of the can mouth 2 and the central axis of the cap unit 1 are significantly misaligned when the cap unit 1 is attached to the can mouth 2, the guiding action of this inclined surface guides the eccentricity to be small, preventing the elastic hook 111A from bending inward. In addition, the outward extension 104a partially has an outward extension (thin slit membrane portion) 105b that is thinner than the surrounding area.

The outer corner cover portion 104b is engaged with the corner where the lower end surface 112B of the opening of the imaginary cylinder with a generally topped cylinder and the outer wall of the imaginary cylinder with a generally topped cylinder side wall 111B intersect over the entire circumference, preventing the hanging portion 103 and the outer portion 104 from coming off the elastic hook piece 111A, and at the same time, it also plays the role of a cover to prevent liquid from adhering to the fracture surface 112A of the tip of the elastic hook piece, which is prone to rust. Also, the outer corner cover portion 104b partially has an outer corner cover portion (thin slit membrane portion) 105c that is thinner than the surrounding area as a part of it.

The outer raised portion 104c extends upward from the outer peripheral end of the outward extension portion 104a, and has the effect of blocking liquid from flowing around to the fracture surface 112A at the tip of the elastic hook piece, making the elastic hook piece 111A more rust-proof.

Even before the resin packing 10 is stored in the cap 11A with elastic hook-and-loop fastening piece, the can mouth abutment portion 101, the flange portion 102, the hanging portion 103, and the outer portion 104 are molded as a single unit without any open gaps or cuts around the entire circumference, at least to a length sufficient to cover the opening lower end surface 112B of the imaginary approximately top-open cylinder. By doing this, the inner side wall of the elastic hook piece 111A, the fracture surface 112A at the tip of the elastic hook piece, the side groove (the open gap between adjacent elastic hook pieces) 113 of the cap with elastic hook piece, and the fracture surface 114 of the side groove of the cap with elastic hook piece are all completely covered by the can mouth 2, so there is no room for liquid adhering to the can mouth 2 to seep out through the side groove of the elastic hook piece (the open gap between adjacent elastic hook pieces) or small seams, etc., and rust can be more reliably prevented.

In injection molding, a draft angle is provided to allow the molded product to be released smoothly, and in the first embodiment, the draft angle is set to become wider as it goes down from flange 102 to the bottom end of hanging portion 103 (draft angle θ). The diameter of the bottom end of hanging portion 103 is larger than the diameter of flange 102, which is set slightly larger to provide tension against elastic hook piece 111A, but the diameter becomes significantly smaller when the tip of elastic hook piece 111A is engaged in the closed state. Therefore, the fluctuation range of the diameter of the bottom end of hanging portion 103 is large.

In order to smoothly change the diameter of the lower end of hanging portion 103 in response to the above-mentioned vibration, a large number of thin slit membrane portions 105 are formed continuously from hanging portion 103 to outer portion 104 at equal intervals in a radial direction, and thin slit membrane portions 105 extend to the outer end of outer portion 104 in the radial direction on the radial line on which they are formed. As a result, when resin packing 10 is stored in elastic hook-and-loop cap 11A, thin slit membrane portions 105 are folded, so that distortion due to excessive deformation does not occur.

By disposing the thin slit membrane portion 105 partially instead of all around, it is possible to maintain a strength that is not easily crushed or broken. Also, since the portion that is folded when the resin packing 10 is stored in the elastic hook-and-loop cap 11A is thin, it is unlikely to affect the inner diameter of the cap unit 1 (the inner diameter of the apex of the L-shape formed by the lower end of the hanging portion 103 and the outer portion 104).

When the folded thin slit membrane part 105 protrudes from the outer surface of the hanging part 13 or the outer part 104 in the cap unit 1, depending on the extent, the protruding part hits the lower inner wall of the elastic hook piece 111A or the fracture surface 112A at the tip and is pushed inward, reducing the inner diameter of the cap unit 1. However, if the rotational positions of the folded thin slit membrane part 105 and the side groove 113 of the cap with elastic hook piece are the same, the folded part fits into the gap space of the side groove, so the change in the inner diameter is small. Since the inner diameter dimension of the cap unit 1 is related to the ease of attachment to the can mouth 2 and the airtight performance, if the difference caused by the rotational position relationship between the thin slit membrane part 105 and the side groove 113 of the cap with elastic hook piece is large when the cap unit 1 is assembled, there is a high possibility that the use of the cap unit 1 will be hindered. Considering that adjusting this rotational position during manufacture is costly and that the user may have to reassemble the cap unit, it is desirable for the folding portion to be thin-walled so that there is as little difference in inner diameter as possible depending on the rotational position, i.e., so that the amount of protrusion of the folding portion is minimized.

The thin slit membrane portion 105 is formed integrally and continuously from the upper end of the hanging portion 103 to the outer portion 104, with the hanging portion (thin slit membrane portion) 105a, the outward extension portion (thin slit membrane portion) 105b, and the outer corner cover portion (thin slit membrane portion) 105c.

The pleats formed by the hanging portion 103 and the thick portion of the outer portion 104, which are divided by the thin slit membrane portion 105, are connected to adjacent pleats by the thin slit membrane portion 105, so that each pleat is unlikely to rotate independently and the inward folding phenomenon in which the outer portion 104 enters the inside of the elastic hook-fastening piece 111A is unlikely to occur.

The outer surface of the hanging portion (thin slit membrane portion) 105a is flush with the outer surface of the thick portion of the hanging portion 103. This reduces the amount by which the folded portion protrudes inward from the thick portion of the hanging portion 103 when the resin packing 10 is stored in the elastic hook-and-loop cap 11A and the hanging portion (thin slit membrane portion) 105a is folded. In particular, if the protrusion amount on the lower side of the hanging portion (thin slit membrane portion) 105a becomes large, there is a risk that the hanging portion will rub strongly against the can mouth 2 when the cap unit 1 is attached to the can mouth 2 and be damaged, so this is avoided.

The outer end of the thin slit membrane portion 105 is limited to a length sufficient to cover 1.3 times the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top-ended cylinder. It is desirable that the outer end of the thin slit membrane portion 105 extends only inward from the distance sufficient to cover 3 times the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top-ended cylinder. By keeping it short, the amount of protrusion from the outer portion 104 when the resin packing 10 is stored in the elastic hook-equipped cap 11A and the outward extension portion (thin slit membrane portion) 105b is folded can be kept small.

If the thick part of the outer part 104 protrudes too much below the bottom surface, the thin slit membrane part 105 may be damaged by collision with other cap units in the case during transportation of the cap unit 1, or may be damaged by strong rubbing against the can mouth 2 during installation, or the thin part protruding beyond the inclined surface of the bottom surface of the outer part 104 may come into contact with the can mouth 2 when installed on the can mouth 2, resulting in insufficient guiding function, or the total height may increase and cause a chute to get clogged during transportation when capping is performed using automatic equipment, reducing work efficiency. These problems can be avoided as much as possible. In the first embodiment, even if the thin slit membrane part 105 extends to three times the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top-closed cylinder (even if the distance of 1.3α in FIG. 3 is increased to 3α), the folding protrusion of the thin slit membrane part 105 does not affect the total height of the cap unit 1. In addition, since the upper surface of outward extension portion (thin slit membrane portion) 105b is flush with the upper surface of the thick portion of outer portion 104, the amount by which it protrudes below the bottom surface of outer portion 104 is further reduced.

Conversely, if the amount of protrusion above the upper surface of the outer part 104 becomes too large, depending on the extent, the protruding part may interfere with the sealing member 12 and be pushed downward and inward. As a result, the tip of the elastic hook piece 111A, which was stably engaged with the dogleg-shaped folded part formed by the lower end of the hanging part 103 and the outer part 104, becomes more likely to come off, and the outer part 104 becomes more likely to enter inside the elastic hook piece 111A, causing an inward folding phenomenon.

Also, keeping the length to the outer end of the thin slit membrane portion 105 short means, in other words, reducing the connection between the thick portion of the outer portion 104 and the thin slit membrane portion. As a result, when the resin packing 10 is stored in the cap 11A with elastic hook, when the interval between the folds formed by the hanging portion 103 divided by the thin slit membrane portion 105 and the thick portion of the outer portion 104 is reduced, the load that the thick portion of the outer portion 104 receives from the folded thin slit membrane portion 105 is reduced. As a result, it is also possible to avoid distortion or deformation of the folds.

The closure member 12 is made of elastic polyethylene, and the annular top wall 120 and the side wall 121 are integrally formed by injection molding. The side wall 121 extends downwards almost vertically from the annular top wall 120, and when assembled into the cap unit 1, it presses the side wall of the cap 11A with elastic hook inward, thereby preventing the cap 11A with elastic hook from opening unexpectedly and preventing the cap unit 1 from floating due to an increase in internal pressure, causing the contents to leak.

The configuration of the cap unit in the first embodiment has been described above. The procedure for using the cap unit according to the present invention will now be described.

The procedure for assembling the cap unit will be described using the first embodiment as an example. First, the resin packing 10 is placed on the cap 11A with the elastic hook 111A in the open state, and the tip of the elastic hook 111A is brought into contact with the flange 102. Since the surface is smoothly connected from the flange 102 to the lower end of the hanging part 103 and there is tension against the elastic hook 111A, when the resin packing 10 is pressed in from this state, the tip of the elastic hook 111A is guided until the tip of the elastic hook 111A is engaged with the dogleg-shaped folded part formed by the lower end of the hanging part 103 and the outer part 104 while maintaining the contact and rotating and deforming the flange 102 and the hanging part 103 inward. Then, the upper wall 110 of the cap with elastic hook is pushed up from the bottom together with the packing body 100 to close the elastic hook 111A. At this time, the many thin slit membrane parts 105 arranged radially are folded, and the diameter of the lower end of the hanging part 103 of the resin packing 10 and the diameter of the outer part 104 are smoothly reduced. The amount of protrusion of the folded outward extension part (thin slit membrane part) 105b is kept small by shortening the distance to the outer end of the thin slit membrane part 105, which prevents the thick part of the outer part 104 from protruding from the bottom surface, thereby minimizing the risk of fragments being mixed into the can due to damage to the outward extension part (thin slit membrane part) 105b. Although the diameter of the lower end of the hanging portion 103 is reduced, a force is applied to the hanging portion 103 to expand outward due to its elasticity, so that the hooked state of the tip of the elastic hook piece 111A is stabilized. Finally, the elastic hook piece 111A is stored in the closure member 12 in the closed state to form the cap unit 1.

The procedure for attaching the cap unit to the can mouth will be described using the first embodiment as an example. The cap unit 1 is placed on the can mouth 2 so that the central axes are as aligned as possible, and the outer part 104 is brought into contact with the upper arc part 20 of the can mouth. Next, when the upper surface of the cap unit 1 is pressed downward, it is lowered along the upper arc part 20 of the can mouth while expanding the inner diameter of the lower end of the hanging part 103, and the tip of the elastic hook piece 111A is engaged with the inclined upper part of the side wall recess 21 of the can mouth via the lower end of the hanging part 103. During this can mouth fitting process, the inner side wall of the cap with elastic hook 111A, the side groove (open gap between adjacent elastic hooks) 113 of the cap with elastic hook, and the fracture surface 114 of the side groove of the cap with elastic hook are kept completely covered over the entire periphery by the can mouth abutment portion 101, flange portion 102, hanging portion 103 (including hanging portion (thin slit membrane portion) 105a), and outer portion 104 (including outward extension portion (thin slit membrane portion) 105b and outer corner cover portion (thin slit membrane portion) 105c) of the resin packing 10. As a result, even if liquid adheres to the can mouth 2 due to dripping or the like, the liquid will not reach the elastic hook 111A, preventing rust. In addition, since the tip of the elastic hook piece 111A is covered on its entire periphery, it is possible to prevent injury to fingers, the opening of the can, etc.

Although the first embodiment of the present invention has been described above, the scope of application of the present invention is not limited to this.

For example, in the second embodiment shown in Fig. 7, a plug type resin packing 10 is used that has a tubular portion 100d to improve adhesion with the inner diameter of the mouth of the can mouth 2. In the plug type, unlike the first embodiment, the upper wall 110 of the cap with elastic hook cannot be pushed up from the bottom together with the packing body 100, so the cap unit 1 is assembled with the elastic hook 111A closed. In addition, the outer corner cover portion (thin slit membrane portion) 105c of the resin packing 10 is not provided, and the outer extension portion (thin slit membrane portion) 105b extends to the outer end. In the thick portion, the outer extension portion 104a is shorter than in the first embodiment, and the outer rising portion 104c having the outer corner cover portion 104b as a part of it on the inner circumference of the lower end extends upward from the outer end of the outer extension portion 104a, and its length is longer than the outer rising portion 104c of the first embodiment.

The closure member 12 in the second embodiment is made of metal, and when the cap unit 1 is attached to the can mouth 2, the bottom is fastened inward by the elastic hook piece 111A, the hanging part 103, and the outer rising part 104c, so that the cap unit 1 does not easily come off. The shape and combination of the cap unit 1 are not limited to these and may be selected from within the range to which the present invention is applicable.

The cap with elastic hook 11A in the first embodiment is made of tinplate and has 10 elastic hook pieces 111A at equal intervals, but this is not limited as long as it does not interfere with the function. In the first embodiment, which is an example in which the thin slit membrane part 105 is partially provided, the folds divided equally by the thin slit membrane part 105 are 10 pieces (see FIG. 4), and the number of folds is the same as the number of elastic hook pieces 111A, but the number does not necessarily have to be the same, and they do not have to be spaced equally. The intervals, number, and material of the folds can also be freely selected within a range that does not interfere with the function.

The width and spacing of the pleats (thick portions) may be appropriately selected and set as described above, but in order for the tip of the elastic hook-and-loop piece 111A to be firmly engaged with the plastic packing, or for the tip of the elastic hook-and-loop piece 111A to be firmly engaged with the can mouth 2 via the plastic packing 10 when the cap unit 1 is attached to the can mouth 2, it is preferable that 60% of the arc length of the fracture surface 112A of the tip of the elastic hook-and-loop piece rests on the pleats (thick portions) and not on the thin portions.

The number of folds (thick portions) may be appropriately selected and set as described above, but the more the number, the less the protrusion when the thin slit membrane portion 105 is folded. Also, if the number is too small, the fracture surface 112A at the tip of the elastic hook piece in the closed state may deviate significantly from the approximately arc shape, and the tip of the elastic hook piece 111A may come off.

In cases where a thin slit membrane portion 105 is provided, some of the variations in the combination of the shape of the thin slit membrane portion 105 (solid line: end face of line D-D in Figure 4(c)) and the thick portion (pleats) that is not thinned (solid line: end face of line E-E in Figure 4(c)) are shown in Figures 9 and 10.

FIG. 9I shows the same shape as in the first embodiment.

The configuration of FIG. 9(ii) that differs from the first embodiment will be described below.

In Fig. 9(ii), the thin slit membrane portion 105 extends upward to the flange portion 102 (105e). Since the flange portion 102 is located at the top, the diameter does not change much before and after the resin packing 10 is stored in the cap 11A with elastic hook. Therefore, the gap between adjacent pleats in the flange portion 102 does not narrow much, so the folding wrinkles that occur when the hanging portion (thin slit membrane portion) 105a is folded are also distributed to the upper flange portion (thin slit membrane portion) 105e, and the folding protrusion is suppressed. However, in the process of storing the resin packing 10 in the cap 11A with elastic hook, the tip of the elastic hook 111A is pressed strongly against the surface of the flange (thin slit membrane) 105e as it descends, which makes it easy for the flange (thin slit membrane) 105e to be damaged by the tip of the elastic hook 111A. Also, if the thin slit membrane 105 extends upward, the tension on the cap 11A with elastic hook may be weakened.

In Fig. 9(ii), there is no outer corner cover part (thin slit membrane part) 105c, but instead the thin slit membrane part 105 (105b) extends to the outer end of the thick part of the outer part 104, so that liquid adhering to the can mouth 2 is less likely to adhere to the fracture surface 112A at the tip of the elastic hook piece. Also, since the thin slit membrane part 105 (105b) extends to a distance that covers a width 6.2 times (>3 times) the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top-closed cylinder, the folded thin slit membrane part 105 protrudes more from the thick part of the outer part 104.

Next, the configuration of FIG. 9(iii) is particularly different from that of the first embodiment, and the points not shown in FIG. 9(ii) will be described below.

In Fig. 9 (iii), thin slit membrane portion 105 is provided from a position below the upper end of hanging portion 103. In this manner, the length to the upper end of thin slit membrane portion 105 may be shortened within a range that can accommodate the opening and closing of elastic hook piece 111A.

In addition, there is no outer corner cover portion 104b or outer raised portion 104c around the entire circumference, but instead the outer portion 104 (104a, 105b) extends to a length sufficient to cover a width that is 2.6 times (>1.5 times) the plate thickness width α of the opening lower end surface 112B of the imaginary approximately topless cylinder around the entire circumference, so that liquid adhering to the can mouth 2 is less likely to adhere to the fracture surface 112A at the tip of the elastic hook piece.

As shown in Fig. 9(iii), if the inner surface of the hanging portion (thin slit membrane portion) 105a is flush with the inner surface of the thick portion of the hanging portion 103, the amount by which the folded hanging portion (thin slit membrane portion) 105a protrudes from the outer surface of the thick portion of the hanging portion 103 is reduced when the resin packing 10 is stored in the cap 11A with elastic hook, so that the hanging portion (thin slit membrane portion) 105a is less likely to be damaged by the tip of the elastic hook 111A. However, if the protrusion amount of the lower side of the hanging portion (thin slit membrane portion) 105a becomes too large, there is a risk that it will be rubbed strongly against the can mouth 2 and damaged when the cap unit 1 is attached to the can mouth 2, so in Fig. 9(iii), the lower side of the hanging portion (thin slit membrane portion) 105a is inclined downward and outward to escape outward.

Next, the configuration of FIG. 9(iv) is particularly different from that of the first embodiment, and the points not shown in FIGS. 9(ii) and (iii) will be described below.

In Fig. 9(iv), the hanging portion (thin slit membrane portion) 105a and the outward extending portion (thin slit membrane portion) 105b are located near the center of the thickness of the thick portion of the hanging portion 103 and the thick portion of the outward extending portion 104a, respectively. Although there is no outer corner cover portion (thin slit membrane portion) 105c, the thick portion is provided with an outer corner cover portion 104b, and an outer rising portion 104c having this outer corner cover portion 104b as a part thereof is also provided. In addition, the outward extending portion (thin slit membrane portion) 105b extends beyond the outer end of the thick portion of the outer portion 104.

Next, with regard to FIG. 9(v), the configuration which is particularly different from the first embodiment will be described below, focusing on the points not described in FIGS. 9(ii) to 9(iv).

In Fig. 9(v), both the thin and thick portions of the outer portion 104 have an outer upright portion (thin slit membrane portion) having an outer corner cover portion 104b (including 105c) below it. In addition, since the lower surface of the outward extension portion (thin slit membrane portion) 105b is flush with the lower surface of the thick portion of the outer portion 104, when the resin packing 10 is stored in the cap 11A with elastic hook, the amount by which the folded outward extension portion (thin slit membrane portion) 105b protrudes from the upper surface of the thick portion of the outer portion 104 is reduced. If the amount by which the outward extension portion protrudes above the upper surface of the outer portion 104 becomes too large, depending on the degree, the protruding portion may hit the fracture surface 112A at the tip of the elastic hook and be pushed downward and inward, resulting in a smaller inner diameter of the cap unit 1 and affecting the ease of attachment to the can mouth 2, etc. This is avoided by reducing the amount of protrusion.

Next, with regard to FIG. 9(vi), the configuration is particularly different from the first embodiment, and the points not described in FIGS. 9(ii) to 9(v) will be mainly described below.

9(vi), there is no outer corner cover portion (thin slit membrane portion) 105c, and instead, the outward extension portion 105b extends longer than in the first embodiment, and an outer upright portion (thin slit membrane portion) 105d is provided upward from its tip. This outer upright portion (thin slit membrane portion) 105d makes it difficult for liquid adhering to the can mouth 2 to flow onto the upper surface of the outer portion 104.

9(vi), since hanging portion (thin slit membrane portion) 105a has an outward inclination from its upper end to its lower end as it goes downward, when resin packing 10 is stored in cap 11A with elastic hook, the upper part of folded hanging portion (thin slit membrane portion) 105a is unlikely to protrude outward from the outer surface of the thick part of hanging portion 103 and is unlikely to be damaged by the tip of elastic hook 111A. Furthermore, since the lower part is unlikely to protrude inward from the inner surface of the thick part of hanging portion 103, it is unlikely to be damaged by strong friction with can mouth 2 when cap unit 1 is attached to can mouth 2.

Next, FIG. 10(vii) is a configuration that is particularly different from the first embodiment, and the following description will focus on points not described in FIGS. 9(ii) to 9(vi).

Fig. 10(vii) has a thin slit membrane portion 105 (105e, 105b) whose thickness gradually decreases from the flange portion 102 to the outer end of the outer portion 104. The thick portion of the outer portion 104 does not have an outer corner cover portion 104b or an outer rising portion 104c, but the thin portion is provided with an outer corner cover portion (thin slit membrane portion) 105c. Also, the outer corner cover portion (thin slit membrane portion) 105c does not need to be located at the outer end of the thin portion slit membrane portion 105 as in Fig. 10(vii).

Next, with regard to FIG. 10(viii), the configuration is particularly different from the first embodiment, and the points not described in FIGS. 9(ii) to (vi) and FIG. 10(vii) will be described below.

In Fig. 10 (viii), the hanging portion 103 (105a in this figure) and the outer portion 104 (105b in this figure) have no thick portions over the entire periphery and are composed only of the thin slit membrane portion 105. Since there are no thick portions, the strength is weak and they are easily crushed. When adopting this form, it is desirable to supplement the strength by selecting an appropriate material, etc.

Next, regarding FIG. 10(ix), the configuration which is particularly different from the first embodiment will be described below, focusing on the points not described in FIGS. 9(ii) to (vi) and FIGS. 10(vii) and (viii).

In FIG. 10(ix), the thick portion of the outer portion 104 (104a) extends to a length that covers a width 5.2 times (>1.5 times) the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top-top cylinder, but the outer end (105c) of the thin-walled thin slit membrane portion 105 extends only to a width 1.2 times (<1.5 times) the plate thickness width α of the opening lower end surface 112B of the imaginary approximately top-top cylinder. Instead, the outer corner cover portion (thin slit membrane portion) 105c is provided only on the thin portion. Therefore, the outer portion 104 has at least one of the following over the entire circumference: an outer corner cover portion 104b (only the thin portion, 105c in this figure) or extends outward until it covers a width 1.5 times or more the width α of the opening lower end surface of the imaginary approximately top-top cylinder (only the thick portion in this figure).

Some of the variations in the configuration in the case where the thin slit membrane portion 105 is provided have been described above, but in the case where the thin slit membrane portion 105 is not provided (for example, FIG. 11 (iii) (iv) described later), some of the variations can be obtained by replacing the reference numeral 105 in FIG. 9 and FIG. 10 with 102, 103, or 104. (105a→103, 105b→104a, 105c→104b, 105d→104c, 105e→102)

Some schematic diagrams of variations in the connection (or adhesion) between adjacent thick-walled sections (pleats) are shown in Figure 11 (end surface of line F-F or line G-G in Figure 6). The upper figures show the state before the resin packing is stored in the elastic hook-and-loop cap, and the lower figures show the state after it is stored and the gap between the pleats is reduced.

Fig. 11(I) is the same shape as the first embodiment. For convenience, the lower figure shows the state in which the thick part (fold) is shortened and the thin slit membrane part 105 (105a, 105b) is folded and protrudes, but if the rotational positions of the thin slit membrane part 105 and the side groove 113 of the elastic hook-attached cap do not match, the protruding peak is pressed and crushed by the tip of the elastic hook-attached piece 111A, so the protruding height becomes lower than in this figure.

In Fig. 11 (II), creases are made in advance in the thin slit membrane portion 105 (105a, 105b). By making creases, the protruding direction (whether it protrudes upward or downward in this figure) can be controlled, and by making multiple creases, the amount of protrusion can be reduced.

In Fig. 11 (III), creases are made in advance in the thin slit membrane portion 105 (105a, 105b). By making creases, the protruding direction (whether it protrudes upward or downward in this figure) can be controlled, and by making multiple creases, the amount of protrusion can be reduced.

In FIG. 11 (III), the thin slit membrane portion 105 is not provided, and the thick portion (pleats) has a curved valve at the end. Before the resin packing 10 is stored in the cap 11A with elastic hook, there is an open gap between the valves. After the resin packing 10 is stored in the cap 11A with elastic hook, the tips of the valves come into close contact with each other, so that the inner surface of the imaginary approximately top-end cylindrical side wall 111B and the opening lower end surface 112B are covered over the entire circumference. Since there is no thin slit membrane portion 105, there is no load applied to the thick portion (pleats) when it is folded, and there is no adverse effect due to the protrusion of the folding. However, since the thick portions (pleats) are not integrally connected and molded, there is a possibility that liquid adhering to the can mouth 2 may seep out through a small gap at the close contact portion.

When removing the cap 11A with elastic hook from the can mouth 2, the elastic hook 111A is opened and removed together with the resin packing 10. Therefore, if the cap is to be reattached to the can mouth 2 without using up all the contents of the can after removal, it is preferable that the valve in Fig. 11 (III) is in close contact even with the elastic hook 111A open. If the valve is not in close contact with the elastic hook 111A open, liquid adhering to the inner surface of the hanging part 103 or the underside of the outer part 104 is likely to seep out from the gap between the valve and adhere to the elastic hook 111A when the cap 11A with elastic hook is removed from the can mouth 2.

Furthermore, when the cap 11A with the elastic hook is removed, it is often the case that only the plastic packing 10 is left behind on the can mouth 2. In such a case, when the cap unit 1 is to be used again, it is necessary to remove the plastic packing 10 from the can mouth 2 and reassemble the cap unit 1, but if there are open gaps between the thick portions (folds) of the plastic packing 10 before it is made into the cap unit 1 as shown in Fig. 11 (III), liquid adhering to the inner surface of the hanging portion 103 or the underside of the outer portion 104 is likely to seep out from the gaps and adhere to the elastic hook 111A during the work of reassembling the cap unit 1.

In Fig. 11 (IV), the thin slit membrane portion 105 is not provided, and when the resin packing 10 is stored in the cap 11A with elastic hook, the ends of the thick portions (folds) overlap and adhere to each other. An inclined surface is formed at the tip of the overlapping portion, so the overlapping portion overlaps smoothly. In addition, the maximum total thickness of the overlapping portion is slightly thicker than the thickness of the thick portions (folds), so the adhesion is high. Since the overlapping distance is longer than that of the valve type in Fig. 11 (III), liquid is less likely to pass through, but since there is no thin slit membrane portion 105, there are advantages and disadvantages similar to those of the valve type.

In Fig. 11(V), hanging portion 103 (105a in this figure) and outer portion 104 (105b in this figure) have no thick portions over the entire periphery and are composed only of thin slit membrane portion 105. Since there are no thick portions, the strength is weak, but since the folding of thin slit membrane portion 105 (105a, 105b) is distributed over the entire periphery, the amount of protrusion is kept small.

Although not shown, if the entire peripheral surface is covered only with the thick portion without providing the thin slit membrane portion 105 as opposed to FIG. 11(V), there is a high possibility that large distortion will occur due to excessive deformation when the resin packing 10 is stored in the cap with elastic hook 11A, and that the tip of the elastic hook 11A will not be securely locked to the lower end of the hanging portion 103. Even if it can be stored normally in the cap with elastic hook 11A, when the thick portions are folded together, the inner diameter of the cap unit 1 (the inner diameter of the apex of the dogleg shape formed by the lower end of the hanging portion 103 and the outer portion 104) will be extremely small. Therefore, in order to form the entire peripheral surface with the thick portion, it is necessary to devise a way to make it easier to fold, such as making a crease or enlarging the inner diameter of the tip of the elastic hook cap 11A in advance.

11(I) to (V) show some of the variations in the connection (or adhesion) portions between adjacent thick portions (folds) in hanging portion 103 (end surface along line F-F in FIG. 6) and outward extending portion 104a (end surface along line G-G); however, by replacing reference numerals 105a and 105b in FIG. 11 with 105c, 105d and 105e, and by replacing reference numerals 103 and 104a with 102, 104b and 104c, the variations also become some of the variations in flange portion 102, outer corner cover portion 104b and outer rising portion 104c.

As the above, the first embodiment (see FIG. 1), the second embodiment (see FIG. 7), and the embodiments shown in FIGS. 9, 10, and 11 have been described as examples of the present invention, and their drawbacks have also been explained. However, it is sufficient to design the device appropriately so that these drawbacks are kept to a level that does not adversely affect actual use. Furthermore, the scope of application of the present invention is naturally not limited to these above-mentioned examples. The present invention also includes examples of combinations of known or commonly used technologies, partial substitutions, and modifications that can be easily conceived by a person skilled in the art.

The following provides supplementary explanations of terms, symbols, and drawings in the text. The thin slit membrane portion 105 (105, 105a, 105b, 105c, 105d, 105e) is a membrane without open gaps or cuts. The "fold" is a portion formed of a thick portion divided and connected by the thin slit membrane portion 105 in an embodiment having the thin slit membrane portion 105. The flange portion 102, the hanging portion 103, the outward extension portion 104a, the outer corner cover portion 104b, and the outer rising portion 104c each include the thin slit membrane portion 105 (105e, 105a, 105b, 105c, 105d) when they each have a thin slit membrane portion. For example, the "hanging portion 103" includes the "thick portion of the hanging portion 103" and the "hanging portion (thin slit membrane portion) 105a". The outer rising portion (104c, 105) only needs to extend upward from the outer extension portion (104a, 105b), and does not necessarily need to extend from the outer end like the outer rising portion 104c in the first embodiment. The outer corner cover portion (104b, 105c) extends upward from the outer extension portion (104a, 105b), so it can also be called the outer rising portion (104c, 105d). Figures 1, 2, 3, and 7 are cross-sectional views of the cap unit 1, but for convenience, a cross-section of a portion where there is no protrusion due to folding of the thin slit membrane portion 105 is shown.

1 Cap unit 10 Resin packing 100 Packing main body 100a Flat part 100b Annular protrusion 100c Conical expansion part 100d Cylindrical part 101 Mouth abutting part 101a Thick part 101b Outside vertical part 102 Brim part 103 Drooping part 104 Outer part 104a Outward extension part 104b Outer corner cover part 104c Outer mullion upper part 105 Thin slit film part 105a Hanging part (thin slit film part)
105b Outward extension part (thin slit membrane part)
105c Outer corner cover part (thin slit membrane part)
105d Outer mullioned upper part (thin slit membrane part)
105e flange (thin slit membrane)
θ Draft angle 11A Elastic hook-attached cap 11B Imaginary cylinder with a substantially topped top 110 Upper wall 111A Elastic hook-attached piece 111B Imaginary cylinder with a substantially topped top side wall 112A Fracture surface 112B at the tip of the elastic hook-attached piece Bottom of the opening of the imaginary cylinder with a substantially topped top End surface 113: Side groove of the elastic hook cap (open gap between adjacent elastic hooks)
114: Fracture surface of side groove of elastic hook-attached cap α: Width of opening lower end surface of imaginary substantially top-closed cylinder 12: Sealing member 120: Annular upper wall (sealing member)
121 Side wall (sealing member)
2 Can mouth 20 Upper arcuate portion 21 Side wall recess

Claims (4)

A cap unit is provided in which a resin packing is housed in a cap with elastic hooks, the cap having a top wall that can be freely raised and lowered and a side wall formed of a plurality of elastic hooks that open and close by pressing the top wall, the resin packing having a packing body, a can mouth abutment portion for tightly contacting the top of the can mouth and located annularly on the outer periphery of the packing body, a flange portion extending outward from the outer periphery of the can mouth abutment portion, and a hanging portion extending downward from the flange portion,
When the elastic hook cap is viewed as an imaginary cylinder having an approximately circular open lower end surface that virtually covers the open gap between the adjacent elastic hooks and is flush with the fractured surfaces of the tips of the elastic hooks,
The resin packing has a hanging portion that extends to the opening lower end of the imaginary approximately topped cylinder and an outer portion that extends outward from the lower end of the hanging portion, and when the cap unit is attached to the can mouth, the outer portion abuts the upper arc portion of the can mouth and then descends along the upper arc portion of the can mouth while widening the inner diameter of the lower end of the hanging portion, and then enters into the side wall recess of the can mouth and engages therewith, and while the cap unit is attached to the can mouth, the side inner wall of the imaginary approximately topped cylinder is covered over its entire circumference by the hanging portion, the brim portion, and the can mouth abutment portion, and the lower end surface of the opening of the imaginary approximately topped cylinder is also maintained in a state in which it is covered by the outer portion against the can mouth over its entire circumference. The cap unit described in claim 1, characterized in that before the plastic packing is stored in the cap with elastic hook, it is molded as a single unit without any open gaps or notches around the entire circumference, from the can mouth abutment portion to the flange portion, from the flange portion to the hanging portion, and from the hanging portion to the outer portion, until the plastic packing is stored in the cap with elastic hook, and the length of the entire circumference is such that it completely covers the opening lower end surface of the imaginary approximately top-open cylinder over the can mouth when the plastic packing is later stored in the cap with elastic hook. A cap unit as described in claim 2, characterized in that the hanging portion and the outer portion share a plurality of thin-walled slit membrane portions arranged radially and thinner than the surrounding areas, and the thin -walled slit membrane portions extend from the hanging portion to the outer end in the radial direction on the radial line on which the thin-walled slit membrane portions of the outer portion are formed. A cap unit as described in any one of claims 1 to 3, characterized in that the outer portion has at least one of an outer corner cover portion that covers the corner where the opening lower end surface of the imaginary approximately topped cylinder intersects with the outer wall around the entire circumference, or a width that is 1.5 times or more the width of the opening lower end surface of the imaginary approximately topped cylinder extends outward until it completely covers the can mouth .

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