BACKGROUND OF THE DISCLOSURE

5 FIELD OF THE DISCLOSURE

The present disclosure generally relates to a screw cap, and more particularly to a screw cap for containers with a threaded neck.

DESCRIPTION OF RELATED ART

- 0 Screw caps are used to hold liquid in a container having a threaded neck. However, liquid or beverage containing high proportion of carbon dioxide in a container may result in considerable strain on both the container (e.g. a bottle) and the screw cap. To address this issue, screw caps with good sealing properties have been proposed, but which are not adequate in various respects.

_ 5 BRIEF SUMMARY OF THE DISCLOSURE

A screw cap configured for capping a neck of a container is disclosed. The screw cap includes a top panel, a sidewall, an inner sealing ring and a outer sealing ring. The top panel has a top surface and a bottom surface. The sidewall projects from a periphery of the bottom surface of the top

1 0 panel and has an open end through which to receive the neck. The inner sealing ring downwardly extends from the bottom surface of the top panel, while the outer sealing ring downwardly extends from the bottom surface of the top panel and concentrically surrounds the inner sealing ring. The top panel further has an undercut on the bottom surface surrounding the inner foot of the inner sealing ring to form a first thickness, the top surface and the bottom surface between the inner 5 sealing ring and the outer sealing ring form a second thickness, and the second thickness is greater than the first thickness.

Another screw cap further comprises a separable annular band connected to the open end of the annular sidewall by a plurality of bridges.

5 0 In another embodiment, the bridges connecting the separable annular band and the annular sidewall are small webs of material that are broken with first attempted removal of the screw cap from the neck of the container.

5 In another embodiment, the annular band has a series of annularly-spaced cams disposed on an inner face of the annular band.

In still another embodiment, the cams are jointed together by a shallow taper ring.

_ 0 Another screw cap further comprises a plurality of radial stops projected from the bottom surface of the top panel between the inner and outer sealing rings.

In another embodiment, the inner sealing ring of the screw cap has a height ranged from 3.0 to 4.5 mm.

_ 5

In another embodiment, the outer sealing ring of the screw cap has a height ranged from 0.8 to 1.8 mm.

In another embodiment, the first thickness of the cap, i.e., the thickness of the top panel at the 1 0 undercut portion, is ranged from 0.75 to 1.15 mm.

In another embodiment, the second thickness of the cap, i.e., the normal thickness of the top panel, is ranged from 1 to 1.5 mm. 5 In another embodiment, each of the radial stops of the screw cap has a height ranged from 0.2 to 0.6 mm.

In another embodiment, each of the radial stops of the screw cap has a width ranged from 1.3 to 1.8 mm. BRIEF DESCRIPTION OF THE DRAWING

The following detailed description of the preferred embodiments of the present disclosure will be better understood when read in conjunction with the appended drawings. The present disclosure is 5 illustrated by way of example, and not limited by the accompanying figures, in which like references indicate similar elements.

FIG. 1 is an overall view of a screw cap in accordance with one of the example embodiments of the present disclosure;

_ 0

FIG. 2 is a sectional view of a screw cap in accordance with one of the example embodiments of the present disclosure;

FIG. 3 is a sectional view of a screw cap engaged with a threaded neck 40 in accordance with one _ 5 of the example embodiments of the present disclosure;

FIG. 4 illustrates an internal structure of a screw cap in accordance with one of the example embodiments of the present disclosure;

1 0 FIG. 5 is an enlarged sectional view of a part of a screw cap in accordance with one of the example embodiments of the present disclosure;

FIG. 6 is an enlarged sectional view of a stop of a screw cap in accordance with one of the example embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present disclosure, and is not intended to represent the only form in ] 0 which the present disclosure may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

FIG. 1 is an overall view of a screw cap in accordance with one of the example embodiments of 5 the present disclosure. As illustrated, the screw cap 10 is configured to cap a neck 40 (see FIG. 3) at the inlet of a container such as, for example, a beverage bottle. The screw cap 10 may be made from thermoplastics such as, for example, Polyethylene or Polypropylene. The screw cap 10 includes a top panel 11 and a sidewall 12. The sidewall 12 projects from a bottom of the top panel 11. The sidewall 12 has an open end through which to receive the neck 40 of the container. The screw cap L 0 10 has but is not limited to a tubular envelope shape that surrounds, in use, the neck 40 (see FIG. 3).

A separable annular band 14 is connected to the open end of the sidewall 12 by a plurality of bridges 143, illustrated in details in FIG. 2. The separable annular band 14 is also known as "anti- tamper band" or "tamper evident band," since it will be grasped by the neck 40 and breaks away from the sidewall 12 with initial removal of the screw cap 10 from the neck 40 to provide a visual L 5 indicator of tampering. An embossed knurl pattern 13 is formed on the annular periphery of the sidewall 12, so as to enhance the friction of the annular periphery and make the screw cap easier to twist off or twist on.

FIG. 2 is a sectional view of a screw cap 20 in accordance with one of the example embodiments 1 0 of the present disclosure. FIG. 3 is a sectional view of a screw cap engaged with a threaded neck 40 in accordance with one of the example embodiments of the present disclosure. With reference to FIG. 2, a section across the screw cap 20 reveals internal structures thereof. Amongst these are sealing structures that are configured to cooperate, in use, with complementary features on the neck 40 as shown in FIG. 3. The neck 40 generally has an opening at one end and stretches at the 15 other end to hermetically connected with a container, such as a beverage bottle. As illustrated in FIG.2, the top panel 11 has top surface and a bottom surface, the annular sidewall 12 projects from a periphery of the top panel 11 on one end. A cap thread 121 is disposed on the inner annular surface of the sidewall 12. The cap thread 121 cooperates, in use, with a complementary outer thread 41 defined on an outer surface of the annular neck 40. As may be appreciated with reference ] 0 to FIG. 2, the cap thread 121 includes gaps along its helical extent that define vents "V" for equalizing pressure of the contents of the container with start of removal of the screw cap 20 from the neck 40. An inner sealing ring 111 and an outer sealing ring 112 downwardly extend from the bottom surface of the top panel 11, wherein the outer sealing ring 112 concentrically surrounds the inner sealing ring 111. The inner sealing ring 1 11 and the outer sealing ring 112 define a sealing chamber "S" therebetween within which to sealingly receive an annular inlet portion of the neck

5 40 (see FIG. 3). Both the inner sealing ring 11 1 and the outer sealing ring 112 have an annular construction that allow them to elastically deform and/or comply to the complementary sealing structures on the neck 40. As may be appreciated with reference to FIG. 3, an outwardly facing annular lobe 111a on the inner sealing ring 111 is configured to sealingly contact an inner sealing surface of the neck 40. Likewise, an inner surface of the outer sealing ring 112 is configured to

L 0 sealingly contact an outer sealing surface of the neck 40.

Referring back to FIG. 2, the screw cap 20 further includes a number of radial stops 24 that project from the bottom surface of the top panel 11 in between the inner sealing ring 111 and the outer sealing ring 112, and that join the inner sealing ring 111 with the outer sealing ring 112. The shape

L 5 and arrangement of the radial stops 24 is shown with reference to FIGS. 4 and 6. The radial stops 24 control the application height of the screw cap 20 onto the neck 40. The foregoing may be appreciated with reference to FIG. 3 wherein one of the radial stops 24 is shown in abutment with the top face of the annular neck 40. Each radial stop 24 rises up a little bit from the bottom surface of the sealing chamber "S." Without the stops 24, the neck 40 would be easily able to further 0 penetrate the sealing chamber "S" by about the height of the stops, the outer sealing ring 112 in particular being forced to expand even further, thereby resting more firmly and tightly against the inlet of the neck 40. Furthermore, with reduced contact surface between the cap 20 and the neck 40 at the areas of the stops 24, the cap 20 requires less opening torque.

15 From FIG. 2 it may also be appreciated that the tamper evident band 14 is connected to the open end of the sidewall 12 by a plurality of bridges 143. The bridges 143 are small webs of material that are broken with first attempted removal of the screw cap 20 from the neck 40. A series of annularly- spaced cams 142 are provided on an inner face of the tamper evident band 14, and are joined together by a shallow taper ring 141. On first application of the screw cap 20 onto the neck 40,

] 0 inclined bottom faces of the cams 142 and taper ring 141 are pushed over an outwardly projecting flange band 42 (FIG. 3). Thereafter, complementary locking faces on the opposite sides of the cams 142 and flange band 42 help to capture the tamper evident band 14 on the neck 40. The shallow taper ring 141 stiffens the tamper evident band 14 to provide a good hold on the neck 40 of the container. More specifically, when the screw cap 10 is applied on the neck 40 the taper ring 141 is placed in contact with the flange band 42 (i.e. pilfer ring) of the bottle and thereby apply a preload 5 thereon. This preload improves performance of the screw cap 10 during opening thereof by ensuring proper bridge breaking, reduced hinge band (i.e. one or more bridges that fail to break), and otherwise limit the possibility of being able to remove the tamper band without breaking of the bridges (i.e. tamper evidence).

L 0 It will be appreciated that the neck 40 is less deformable than the inner sealing ring 111 and the outer sealing ring 112. When the screw cap 20 is isolated from the neck 40 (i.e. prior to its initial application onto the neck 40), the inner sealing ring 111 has a maximum outer diameter at the annular lobe 111a and a minimum outer diameter at a region closer to the top plate 11. The inner diameter of the neck collar 40 is generally uniform, slightly smaller than the maximum outer

L 5 diameter of the inner sealing ring 111 in isolated state, and slightly larger than or equal to the minimum outer diameter of the inner sealing ring 111 in isolated state. When the inlet of the neck 40 penetrates into the chamber "S," the inner sealing ring 111 will be pushed to deform radially inwards, namely along the direction generally indicated by arrow "R," such that the annular lobe 111a shoves against the inner wall of the neck 40 under recovery force, and the container is sealed. 0 When the neck 40 further penetrates the chamber "S," the inlet of the neck 40 will be in contact with the outer sealing ring 112 and push it to deform radially outwards, such that the outer sealing ring 112 shoves against the outer wall of the neck 40 under recovery force, so as to seal the container more tightly. 5 As illustrated in FIG. 3, internal pressure within the container (e.g. beverage of carbonation) may act on the top panel 11 to cause it deflect (e.g. dome) outwards along the direction generally indicated by arrow "U." With this deformation of the top panel 11, a rotational force may be imparted on the plug seal 111 in a direction 'R' that is away from sealing contact with the inner sealing surface of the annular neck 40. To counter the foregoing, referring to FIGs. 3 and 5, it may

3 0 be further appreciated that the top panel 11 is further provided with an small undercut 19 on the bottom surface of the top plate 11 surrounding the inner foot of the inner sealing ring 111. As illustrated, the undercut 19 provides for additional flexibility of the top panel 11 in the region of the inner sealing ring 11 1 that functions like a hinge to somewhat decouple deformation movement of the top panel 11 from the inner sealing ring 1 11 thereby allowing it to stay in sealing contact with the neck 40.

5

FIG. 4 illustrates an internal structure of a screw cap in accordance with one of the example embodiments of the present disclosure. As illustrated, a total of eight radial stops 24 are uniformly distributed between the first sealing ring 111 and the second sealing ring 112.

_ 0 FIG. 5 is an enlarged sectional view of a part of a screw cap in accordance with one of the example embodiments of the present disclosure. As illustrated in FIG. 5 and referring to FIGs. 2-4, the annular undercut 19 has a curved portion having a radius of curvature R ₃ ranged from 0.5 to 0.9 mm. The cap 20 has a curved portion which has a radius of curvature R ranged from 0.3 to 0.7 mm, at the corner between the top panel 11 and the sidewall 12. The second sealing ring 112 has a

_ 5 height di ranged from 0.8 to 1.8 mm, and the stops 24 have a height d ₃ ranged from 0.2 to 0.6 mm and a length d ₄ ranged from 1.3 to 1.8 mm. The normal thickness d ₂ of the top panel 11 is ranged from 1 to 1.5 mm. The first sealing ring 111 has a height d ₅ ranged from 4.9 to 5.1 mm. The outwardly facing lobe 111a on the first sealing ring 111 has a curved portion having a radius of curvature R ₂ ranged from0.3 to 0.8 mm. The top panel 11 has a thickness de ranged from 0.75 to

1 0 1.15 mm at the undercut portion.

FIG. 6 is an enlarged sectional view of a stop of a screw cap in accordance with one of the example embodiments of the present disclosure. As illustrated, the stop 24 has a trapezoid sectional view, the head surface of the stop 24 having a width d ₇ ranged from 0.8 to2 mm, and the 15 bottom of the stop 24 having a width dg ranged from 1.0 to 2.8 mm.

Even though, adherence to the exact dimensions, as shown in the figures, does not appear necessary. It is nevertheless to be assumed that the advantageous effects of the sealing engagement according to the present disclosure are based on the fact that it reacts relatively ] 0 insensitively to tolerance deviations of the neck collar and also of the actual screw cap itself. While various embodiments of the present disclosure have been illustrated and described, it will be clear that the present disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the present disclosure, as described in the claims.