Knurled pull-tabs   

Abstract: A closure package includes a closure cap and a liner having a pull-tab. The liner is configured for use with a container having a finish or lip portion having a sealing surface at an uppermost portion thereof. The closure cap has a top wall portion and a depending skirt portion depending from the top wall portion. The top wall portion and sealing liner is adapted to coact with the container sealing surface to form a seal therebetween. The liner of the subject invention is for use with a closure package and is disposed in cap, positioned intermediate the top wall portion and the container sealing surface when the cap is positioned on the container. The liner is circular and has a central portion and a tab portion integral with the central portion, extending outwardly from a periphery thereof. The tab is folded on or above a tangent to the periphery of the liner, over the central portion into a folded position, and defines a hinge region at the juncture of the tab and outside the tangential line to the liner circumference. The tab is knurled to provide an improved, secure grip.

FIELD OF THE INVENTION

The invention relates to an inner seal for a container and more particularly to a pull-tab for the inner seal to permit a proper seal while allowing for easy removal of the inner seal to the container.

BACKGROUND OF THE INVENTION

A heat sealable inner seal is often used in sealing a container for products such as anti-freeze, peanut butter, mayonnaise, liquid detergent, etc. Such an inner seal prevents leakage and is also popular for providing an indication of whether there has been tampering with the contents of a container.

Presently, a heat sealable inner seal generally includes a multi layer composite structure with an upper layer of metallic foil which is attached to a lower layer of adhesive material which bonds the heat seal material. The inner seal also can include an upper backing layer. Generally, the inner seals are inserted into caps and shipped to a packager of containers. The packager places the caps onto filled containers, with the coating of heat sealable material being in contact with the land area of the neck of the containers. The containers then pass through a conduction heating system which conducts heat into the foil, under an induction heater which generates heat within the metallic foil causing the temperature of the foil to increase. The high temperature of the foil melts the attached heat sealable adhesive layer, causing the inner seal to bond to the container.

If the foil is heated to too low a temperature, the bonding between the heat sealable layer and container may be weak or may not occur, thus preventing the inner seal from performing its sealing function. If the metallic foil is heated to too high a temperature, the heat sealable layer may burn which may also prevent proper sealing. Therefore, it is desirable to heat the foil to a temperature within a desired temperature range to ensure proper bonding of the inner seal to the container.

In the prior art no tabs have been used or as many as six tabs that are integral with the central portion extend from the periphery of the liner. There may be more tabs used, as will become apparent. The tabs can serve as grasping portions, outside of the sealed periphery of the central portion, that facilitate removing the liner from the container and retaining the liner within the cap.

In one known liner arrangement, a pull-tab is formed as part of the liner to facilitate removing the liner from the container. The pull-tab is a relatively small integral extension of the liner that extends beyond the periphery of the liner that is sealed to the container neck edge.

In order to integrate the pull-tab with a closure package, e.g., a closure cap, a variety of configurations are in use. In one arrangement, the pull-tab is folded over the liner so as to rest within the periphery of the liner, between the liner and the top wall of the cap when the closure cap is placed over the liner, onto the container.

In order to assure that the tab remains flush with the liner material during the manufacturing process, the pull-tab is “hammered” or rolled after it is creased and folded to create a hinge or fold. In the hammering process, a flat, hammer-like striker is driven into the tab at about the fold or simply rolled to permanently crease the material. When using relatively thin or permanently deformable material, such as foil, this arrangement is satisfactory to facilitate the tab remaining flush against the liner.

There are, however, a number of drawbacks to the hammered tab arrangement. First, when a relatively resilient liner material is used, the tab tends to return to its unstressed state, and unfolds, regardless of the force used to hammer the tab into the folded position. This can be particularly troublesome if the closure forming process is stopped and liners have not yet been positioned inside of their respective closure caps. It has been observed that the tabs tend to unfold and often become caught or jammed on the cap threads or inner lip of the container during insertion of the liner into the cap. When this occurs, the liners do not properly seat within the cap and the cap must be rejected. Further, the folded tab may cover too much or too little of the container lip and thus result in an imperfect seal

Accordingly, there continues to be a need for a resilient liner pull-tab therefore that correctly positions the pull-tab during induction sealing so that a positive seal is formed.

SUMMARY

A closure package includes a closure cap and a liner having a pull-tab. The liner is configured for use with a container having a finish or lip portion having a sealing surface at an uppermost portion thereof. The closure cap has a top wall portion and a depending skirt portion depending from the top wall portion. The top wall portion and sealing liner is adapted to coact with the container sealing surface to form a seal therebetween. The closure package includes a liner disposed in the cap, positioned intermediate the top wall portion and the container sealing surface when the cap is positioned on the container. The liner is circular and has a central portion and a tab portion integral with the central portion, extending outwardly from a periphery thereof. The tab is folded on or above a tangent to the periphery of the liner, over the central portion into a folded position, and defines a hinge region at the juncture of the tab and above the tangential line to the liner circumference.

The tab is scored above the hinge region and folded over the central portion to reside within the periphery thereof. The scoring is done to help the tab to lay flat in the closure. The same tab can be held regardless of scoring if a tab or tabs are used on one or both sides of the tab to hold it down.

The tab can be embossed or knurled on one or both sides to assist in gripping the tab to pull the liner off. The folded tab creates a retention area that bias against liner retentive ribs or the cap threads to hold the liner in place in the cap until sealing is performed on the bottle mouth.

FIG. 1 is an exploded perspective view of a closure package and an associated container, the closure package including a liner having a pull-tab embodying the principles of the present invention;

FIG. 2 is top plan view of a die-cut liner illustrating the liner central portion and the pull-tab, with the pull-tab being unfolded from the central portion;

FIG. 3 is a top plan view of the liner of FIG. 2, illustrated with the pull-tab folded back onto the central portion;

FIG. 4 is a partial cross-sectional view of an exemplary laminate structure of the liner material; and

FIG. 5 is a diagrammatic view of the hinge region on the tangential line of the periphery of the liner central portion

FIG. 6 is a top plan view of a liner with a pull-tab with only one holding tab that can be on either side of the pull-tab.

FIG. 7 is a top plan view of a liner with a pull-tab and two holding tabs.

FIG. 8 is a top plan view of the liner of FIG. 7 showing the pull-tab folded over.

FIG. 9 is a cross section view of a cap with a liner in place, showing the pull-tab biasing the liner in place in the cap.

FIG. 10 is a top plan view of a knurled tab.

FIG. 11 is a top plan view of a tab with a knurling pattern of raised squares.

FIG. 12 is a top plan view of a tab with a knurling pattern of concentric circles.

FIG. 13 is a top plan view of a tab with a knurling pattern of diamonds.

FIG. 14 is a top plan view of a tab with a knurling pattern of crosshatching.

FIG. 15 is a top plan view of a knurling pattern of parallel bars.

DETAILED DESCRIPTION

While the present invention is susceptible of embodiment in various foams, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated.

Referring now to the figures and particularly to FIG. 1, there is shown a closure package 10 including a closure cap 12 and a liner 14 embodying the principles of the present invention. The package 10 is for use with an associated container 16. The exemplary container 16 has a threaded neck portion 18 having a finish 20. The finish 20 is that portion of the container 16 including the upper region which engages the cap 12, e.g., the threaded area 18 and an uppermost sealing surface 22 of the container 16. The container threads 18 engage complementary threads (not shown) formed on an inner surface of the cap 12. It will be recognized by those skilled in the art that the closure package 10 described herein can be used with containers having a snap-like or beaded engagement configuration.

The cap 12 has a top wall portion 30 and a depending skirt portion 32 depending from the top wall portion 30. The inner surface 34 of the top wall portion 30 is adapted to co act with the sealing surface 22 of the container 16 to form a seal therebetween. When the package 10 is assembled, the liner 14 comprises a circular disc and resides between the top wall portion 30 of the cap 12 and the sealing surface 22 of the container 16, spanning the opening or mouth 36 of the container 16.

The liner 14 has a central portion 40 that is positioned over and in use, sealed to the sealing surface 22 of the container 16. A tab 42 is integral with the central portion 40, and extends from a periphery 44 thereof so that a one-piece liner results. The tab 42 defines a grasping portion 46, that, when folded, is outside of the sealed periphery 44 of the central portion 40, and is adapted to facilitate removing the liner 14 from the container 16. While shown in various shapes throughout the drawings, no particular shape is intended.

In one embodiment, as illustrated in FIG. 4, the liner 14 is formed from a laminate material M having a resilient substrate layer 50, a foil or like gas-impermeable layer 52, and a heat activated bonding layer 54, such as a heat activated adhesive. In a current embodiment, the resilient substrate layer 50 is a closed cell foam material, but can be chip board or paper backed and/or coated and is relatively impervious to the environs and establishes an air-tight seal between the container 16 contents and the environs. The resilient material layer 50 permits the cap 12 to be closely fitted to, and tightened onto, the container 16.

During the manufacture of the closure package 10, the stock of liner 14 material M is cut to form the liner tab 42. The tab 42 is folded on a hinge line that is on or above a tangential line to the liner disc and the tab 42 is “hammered” or rolled into place. The liner 14 with the folded and hammered tab 42 are cut to form the liner central portion 40, with the tab 42 integral with the central portion 40. Those skilled in the art will recognize that the die that is used to cut the central portion 40 is configured so that it does not sever the tab 42 from the central portion 40 of the liner 14.

Those skilled in the art will recognize that after placement of the liner 14 in the cap 12 and positioning the cap 12 on the container 16, the liner 14 must still be sealed to the sealing surface 22 of the container 16. Sealing can be effected using a variety of known methods. In one method of sealing the liner 14 to the container 16, the package 10 is subjected to heat, e.g., heat sealing, and the heat sensitive sealing layer 54 bonds to the sealing surface 22. Thus, the cap 12 can be removed from the container 16 and the liner 14 remains bonded to the container 16. The bonded liner 14 helps to maintain the contents of the container 16 fresh, and provides tamper indication for the package 10. It is evident that the liner must be kept in place and generally centered in the cap until the liner is sealed on the bottle mouth.

In one method of forming the package 10, a cutting from a stock of the liner material M is made to form a circular liner tab 42. As shown in FIG. 5, the tab 42 is then folded onto the liner 14 material M to form a hinge line 58 along or above a line 80 tangential to the circumference 82 of the line. If the hinge line is above the tangential line, i.e., radially beyond the circumference 82 of the liner, it should not be more than 3 mm above.

The liner 14 material M, is cut to form the liner central portion 40. Those skilled in the art will recognize that the die that is used to cut the central portion 40 is configured such that it does not sever the tab 42 from the central portion 40. The liner 14, having the tab 42 thereon, is subsequently scored, folded, positioned and secured in the closure cap 12 to form the closure package 10. The cap 12 and liner 14 can be placed onto the associated container 16, and the liner 14 sealed to the container 16 by, for example, heat sealing. It will be recognized by those skilled in the art that other methods of sealing the liner 14 to the container 16 can be used to form the tamper-indicating package 10.

As stated above, a primary function of the tabs is to retain the liner in the cap prior to placement on the container and subsequent securing and sealing to the top of the container. A pull-tab is generally larger than a regular tab so as to include a larger surface to grasp when removing the liner from the container. As stated, the pull-tab is generally larger than any regular tabs present, and is sufficiently large to enable a user to grasp and pull to remove the liner from the container mouth. When this larger tab is folded over on top of the liner to fit inside the cap, it exerts a spring effect that tries to push the liner out of the cap during shipping and handling. To counteract this spring effect, the subject invention folds the tab along or above the targeted line 80 radially beyond or outside the circumference 82 of the liner disc 40 (FIG. 5). The hinge line may be formed by a practice called “coining” in which the liner material is lined on both sides in a manner that does not tear the material. When the tab is bent over the liner disc as shown in FIG. 3, it then secures the liner in the cap by pushing up against a thread or liner retention bead 63 biasing the liner against the opposite wall in the cap (see FIG. 9). If the hinge line 80 is sufficiently distanced from the circumference then it may be the only tab necessary for retaining the liner in the cap.

In this embodiment, shown in FIGS. 7 and 8, when the pull-tab is folded over as in FIG. 8, wings 60 and 61 are formed and serve to supplement the retentive function of the pull-tab 42 in the cap, and form retention areas on either side of the pull-tab.

In an alternative embodiment shown in FIG. 6, there may be other tabs 48 about the liner disc, which may be equidistant about the disc circumference or randomly spaced. As many as ten additional tabs may be used, or as little as one or none. It is important when using multiple tabs that at least one of the tabs is adjacent or in proximity to the pull-tab, preferably within 30° of the pull-tab.

An advantage in spacing the hinge line from the circumference of the liner is that the liner disc is better positioned over the bottle mouth so that there is no interference by the tab with the seal on the bottle mouth, i.e., the sealing process by induction heating is not interfered with and a better seal results.

The pull-tabs may be knurled to provide better gripping ability when the tab is pulled for removal from the bottle. The pull-tab 42 in FIG. 9 may be embossed with a square pattern 90, which can be present on one or both sides, or it may be raised dots 91 as shown in FIG. 10, also present on one or both sides. Other possible knurling patterns may also present tremendous, such as cross-hatching (FIG. 14), bars (FIG. 15), concentric circles (FIG. 12), diamonds (FIG. 13) or the like.

In general, knurling involves forming a pattern on the exterior of the tab.

The knurling can be accomplished by embossing teachings well known in the art, or by machining teachings, also well known. One manner of knurling involves rolling a surface having the desired pattern upraised on the surface, thereby making indentations on the surface of the tab.

In practice, the materials used, as well as the dimensions, may be any according to requirements and to the state of the art. Furthermore, the organization and type of the individual elements of the device represent preferred embodiments and should not be read to limit the use of alternate configurations and types. One of ordinary skill in the art can discern, from the description of the instant invention, alternate embodiments that can be contemplated by the designers of the device.