Patent application title: Press-On Closure with Top Sealing Rib
Jeffrey S. Davis (Dekalb, IL, US)
Douglas J. Hidding (Barrington Hills, IL, US)
BLACKHAWK MOLDING CO., INC.
IPC8 Class: AB65D1734FI
Class name: Frangible member or portion about line or point of weakness with gripping means (e.g., pull tab)
Publication date: 2012-11-15
Patent application number: 20120285963
A closure for glass and polycarbonate bottles. The closure is the
press-on and pull off type, i.e., it is unthreaded. The closure has a
down-outwardly extending rib on the underside of the lid that forms a
seal on the upwardly and outwardly facing surface of the neck of the
bottle. The closure has a removable tamper indicating ring connected to
the lower portion of the skirt of the closure by a reduced-thickness tear
strip. In one embodiment, slits are formed in the tear strip to further
increase the sensitivity of the tear strip to tampering. Between the
slits, links in the tear strip act to hold the ring in connection with
the lower portion of the skirt. The circumferential length of the slits
is significantly greater than the circumferential length of the links,
and the slit to link length ratio is preferably at least about 20 to 1,
but may be increased or decreased depending upon the desired level of
tamper evidencing required, and depending upon the amount of interference
between the bead on the ring and the corresponding bulge on the bottle to
which the closure is applied.
1. A closure for a container of the type having a relatively smooth top
surface, a laterally extending bulge and a down-outwardly facing
retention surface below the bulge, the closure comprising a lid, a skirt
with an inwardly extending latch bead at a lower portion of the skirt, a
second retaining bead extending inwardly from a removable
tamper-evidencing ring extending from a lower portion of the skirt, the
ring being joined to the skirt by a tear strip, a continuous sealing rib
extending down-outwardly from the underside of the lid, the rib adapted
to flex laterally as the latch bead engages the down-outwardly facing
retention surface on the container.
2. A closure in accordance with claim 1 wherein the retaining bead on the ring is divided into segments, the latch bead defining a first inside diameter, and the retaining bead segment defining a second inside diameter, the first inside diameter being larger than the second inside diameter.
3. A closure in accordance with claim 1 wherein the inside surface of the skirt is unthreaded.
4. A closure in accordance with claim 1 wherein the tamper-evidencing ring has pull tab integrally formed thereon, the pull tab lying entirely below the elevation of the tear strip.
5. A closure in accordance with claim 1 wherein slits are formed in the tear strip such that links in the tear strip hold the tamper evidencing ring to a lower portion of the skirt.
6. A closure in accordance with claim 5 wherein the circumferential length of slits and links is such that the circumferential length ratio of slit to link is at least 20 to 1.
7. A closure for a container of the type having a relatively smooth top surface, a laterally extending bulge and a down-outwardly facing retention surface below the bulge, the closure comprising a lid, a skirt with an inwardly extending latch bead at a lower portion of the skirt, a second retaining bead extending inwardly from a removable tamper-evidencing ring extending from a lower portion of the skirt, the ring being joined to the skirt by a tear strip, a continuous sealing rib extending down-outwardly from the underside of the lid, the rib adapted to flex laterally as the latch bead engages the down-outwardly facing retention surface on the container, the tear strip having slits such that links in the tear strip hold the tamper evidencing ring to a lower portion of the skirt.
8. A closure in accordance with claim 7 wherein a lift tab is formed on an external portion of the skirt above the tear strip, and a pull tab is formed on the removable tamper evidencing ring below the tear strip, the slits being formed at an elevation in the tear strip above the pull tab and below the lift tab.
9. A closure in accordance with claim 8 wherein the circumferential length of slits and links is such that the circumferential length ratio of slit to link is at least 20 to 1.
BACKGROUND AND SUMMARY
 The cap shown and described herein relates to closures for containers for beverages, such and milk, other dairy products and juice, and in particular to containers formed of glass and polycarbonate, as opposed to the more commonly used blow-molded containers made of HDPE (high density polyethylene).
 Caps typically used on glass and polycarbonate containers in the dairy and juice markets (such as 1/2 gallon bottles), have a plug that seals against the upper portion of the inside surface of the neck of the bottle. A secondary seal is also formed by an outer latch bead that presses against the underside of a bulge near the top of the container.
 Making a closure that is tamper-indicating and that is used on glass bottles (and similarly smooth plastic surfaces) is particularly challenging, because glass is very smooth and has a very low coefficient of friction. Closures applied to glass bottles tend to slide on and off the bottle neck with relative ease without any indication that the closure has been removed and re-installed. The ease with which plastic closures slide on and off very smooth bottle necks makes it difficult to design a reliable closure that shows evidence that a closure has been removed from such necks.
 Many bottles made of glass and polycarbonate are intended to be returnable and re-useable, i.e., the bottlers retrieve the containers, clean them and re-fill them. The array of bottles in systems where bottles are returned and re-used is such that they may be made by different manufacturers or on different forming equipment, and are at least likely to have been made at different times. Furthermore, because the bottles may have been used a number of times, the condition of the surfaces relied upon for sealing and retention may be far less than ideal, and may vary significantly from bottle to bottle. As a result, there is typically significant variation both in the location and condition of the surfaces against which the closures used with such bottles must grip and form an effective seal. Thus, closures used with returnable bottles must be highly accommodating in their design, i.e., they must be able to engage and form an effective seal against surfaces falling within of a relatively wide range of dimensions and a wide range of surface conditions.
 The cap shown and described herein preferably seals against the upper periphery of the neck of the bottle, instead of relying on the inside surface of the neck, as plug-style closures do. It has been found that the dimensional variability in the inside diameter (ID) of the necks of re-useable bottles is such that the inside surfaces of bottle necks is sometimes not the most ideal surface against which to seal.
BRIEF DESCRIPTIONS OF THE DRAWINGS
 FIG. 1 is a top plan view of a first embodiment of a closure as shown and described herein;
 FIG. 2 is a sectional view taken along line A-A in FIG. 1;
 FIG. 3 is an elevational view of a prior art bottle with which the cap of FIGS. 1 and 2 is designed to be used;
 FIG. 4 is an enlarged cross-sectional view of a portion of FIG. 2, showing the sealing rib extending down-outwardly from the underside of the lid.
 FIG. 5 is an enlarged sectional view of a second embodiment having slits to enhance the tamper evidencing properties of the closure.
 FIG. 6 is an elevational view of the second embodiment in combination with a bottle.
 FIGS. 1 and 2 are plan and cross-sectional views, respectively, of a cap 11 designed for sealing a glass or polycarbonate bottle of the type with a neck configuration shown in FIG. 3. The cap 11 includes a lid 13, a skirt 21, and a removable tamper evidencing ring 27. The removable tamper evidencing ring 27 is joined to the lower end of the skirt 21 by a thin tear strip tear strip 29 having a wall thickness substantially less than the thickness of the wall of the skirt 23 and the wall of the ring 27. A circumferentially continuous latch bead 17 extends inwardly from an area just above the lower end of the skirt 23. A set of four interrupted retaining bead segments 19 extend inwardly from the ring 27. The inside diameter defined by the set of latch bead segments 19 is smaller than the inside diameter of the continuous latch bead 17, and the cross-sectional area of a latch bead 19 is greater than the cross-sectional area of the latch bead 17. The skirt 21 of the cap 11 is unthreaded, such that the interference between latch bead 17 and the bulge 14 is the mechanism by which the cap is held onto the bottle 10 once the tamper evidencing ring is removed from the cap 11.
 The larger size and greater inward extent of the beads 19, as compared to the bead 17, provides the cap with a tamper-evidencing feature, whereby the cap is difficult to remove without breaking the tear strip 29. The exterior surface of the skirt 21 is divided into segments that are defined by generally vertical spaces 23 at regular intervals about the periphery of the skirt 21. A pull tab 25 is integrally formed with or otherwise joined or connected to the removable ring 27, such that when a consumer wants to access the contents of the bottle 11, the pull tab may be used to remove the ring 27. After the ring 27 is removed, only the latch bead 17 hold the cap on the bottle 11, and the cap is easily removed and replaced for storage in the consumer's refrigerator.
 FIG. 3 shows a typical bottle 10 for which the cap 11 in FIGS. 1 and 2 is designed. The bottle 10 includes a transport ring 20 and a cap retaining bulge 14 at the upper margin of the neck of the bottle. An upper generally flat surface 12 merges with and lies above the cap retaining bulge 14. Between the bulge 14 and the ring 20 is a reduced diameter section 16. The bulge 14 has a slanted and downwardly and inwardly slanted (i.e., downwardly and outwardly facing) retaining surface 18 that merges with the reduced diameter section 16. An opening in the top has an inside diameter 22.
 A top sealing rib 15 extends downwardly and outwardly (i.e., down-outwardly) from the underside of the lid 13 of the cap 11. The rib 15 presses against an upwardly or upwardly and outwardly facing surface 12 on the bottle 10, which surface is identified in FIG. 3. When installed on a bottle, the continuous latch bead 17 presses against a slanted surface 18 on the lower part of the bulge 14 that extends circumferentially at the upper margin of the bottle neck. The ring 27 includes a pull tab 25 (shown in FIG. 1) extending outwardly from the ring 27 below the elevation of the tear strip 29, and the pull tab is adjacent to a vertically oriented weakened section 31 that designed to tear or break, thereby facilitating removal of the ring 27, when the purchaser of a bottle 10 desires to make use of the contents of the bottle 10.
 FIG. 4 is an enlarged sectional view of the portion of FIG. 2 that includes the top sealing rib 15. The rib 15 has a thickness T of about 0.02 inches (or about 1/2 of a millimeter) measured at about the mid-height location, and an axial extent C of about 0.078 inches (or about 2 mm), which is also approximately the distance of the rib 15 from the inside surface of the skirt 21. The width D of the base of the rib 15 is about 0.05 inches (or about 1.3 mm). The rib 15 makes an angle B with the inside surface of the lid 13 that is about 110 degrees. While the rib 15 is shown in FIG. 4 as having a slightly tapering form, it's form could have a more pronounced taper, or could have a constant thickness over some or all of its length. As the cap 11 is pressed onto the neck of the container 10, the rib 15 contacts the upward and outwardly facing surface 12 and deflects outwardly along that surface 12 forming a seal as the cap 11 is placed on the bottle 10, and the seal is maintained when the latch bead 17 engages the surface 18 on the bottle 10.
 FIGS. 5 and 6 show a second embodiment of a closure for use with bottle necks like the one shown in FIG. 3. The cap 12 is similar in construction to the cap 11, but includes slits 30 formed in the tear strip 29 essentially perforating it and making it even weaker than it would be if the slits are not formed therein. The slits are separated by intact links 32 that hold or maintain the connection between the ring 27 and the lower end of the skirt 21. The slits 32 are preferably evenly spaced along the full length of the tear strip 29, and preferably extend through the strip 29. The purpose of the slits is break when any attempt is made to remove the cap, thus providing visual evidence of tampering with the contents of a bottle to which the cap 12 is applied. The slits 30 render the tear strip very sensitive to tampering in that a relatively small amount of force putting the links 32 in tension or shear will cause those links 32 to break, making it apparent to a consumer that the contents of the bottle 10 may have been tampered with. The slits 30 may be applied by using a sharp slitting tool applied at the elevation of the tear strip, i.e., above the pull tab and below the lift tab 36 (provided to assist the consumer in removing the cap from the bottle for repeated uses after the ring 27 has been removed).
 When standard tamper evidencing caps are applied to very smooth surfaces like glass, it sometimes possible to slide the cap and retaining ring (together) off of the neck of the bottle 10 without breaking the tear strip 29 that connects the ring 27 and bottom of the skirt 21. This is of particular concern when the contents of the bottle is some form of dairy product, which tends to act as a lubricant and further reduce the friction between the closure and the bottle neck. Thus, the addition of slits 30 in the tear strip 29 make it extremely difficult to remove the cap 12 and ring 27 together and intact, i.e., without breaking the links 32 that join the ring 27 to the skirt 21.
 The extent to which the tear strip is weakened by the inclusion of slits 30 separated by links 32 may be adjusted by varying the size (i.e., the circumferential length) of the links 32 and the size (i.e., the circumferential length) of the slits 30. In the embodiment shown in FIGS. 5 and 6, the circumferential length of the links 32 is a small percentage, i.e., less than about 5%, of the circumferential extent of the slits, making the connection between the ring and the skirt significantly weaker than the same would be without slits. This slit to link length ratio (equal to or greater than about 20 to 1) has been found to be particularly useful for use on caps applied to glass and polycarbonate bottles configured as shown in FIG. 3. The sensitivity of the connection between the ring 27 and the skirt 21 will also depend on the interference between (primarily the relative diameters of) the bead segments 19 and the bulge 14 on the bottle to which the cap 12 is applied.
 The foregoing descriptions of specific embodiments have been presented for purposes of illustration and description. They are not intended to be exhaustive, and are not intended to limit the scope of the inventions claimed below to the precise forms disclosed. It will be apparent to persons of ordinary skill in the field of closure design that many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to explain the principles of the inventions claimed below and to demonstrate practical application thereof, and to thereby enable others of ordinary skill in the art to best utilize the claimed inventions.
Patent applications in class With gripping means (e.g., pull tab)
Patent applications in all subclasses With gripping means (e.g., pull tab)