EP0094026B1

EP0094026B1 - Tamperproof beverage closure

Info

Publication number: EP0094026B1
Application number: EP19830104390
Authority: EP
Inventors: Emile L. Munch; Carl E. Koontz
Original assignee: Anchor Hocking LLC
Current assignee: Anchor Hocking LLC
Priority date: 1982-05-06
Filing date: 1983-05-04
Publication date: 1988-08-10
Also published as: AU1445183A; DE3377637D1; EP0094026A3; AU570408B2; EP0094026A2; CA1247555A

Description

The invention relates to a generally cylindrical molded plastic closure cap for sealing a threaded container with high pressure contents and having a disc-like cover with a depending generally cylindrical skirt with container engaging threads on said skirt, a radially inwardly extending circular bead being positioned on said skirt between said cover and said threads forming a liner retaining groove and disk-like flowed-in plastic sealing liner being positioned on the underside of said cover and with its outer edge occupying said groove. Caps of this type are known from EP-A-22 991. The prior art closure caps include a thin rib for holding a sealing liner on the underside of the cap cover. The thin rib engages the closure rim of the container and thus flexes in an undesirable manner.
It is the object of the present invention to provide an improved unitary molded plastic closure cap capable of sealing at high pressure, said cap being capable of being applied by using existing high speed bottle sealing machinery.
This object is achieved by the closure cap as defined in claim 1.
The invention will now be described by reference to the accompanying drawing in which

Fig. 1 is a perspective view of a bottle sealed with a closure cap in accordance with the present invention.
Fig. 2 is a sectional view taken along line 2-2 on Fig. 1 of the closure cap of the invention and a bottle sealed with it.
Fig. 3 is a vertical sectional view illustrating a closure cap in accordance with the present invention being applied to a bottle.
Fig. 4 is a vertical sectional view of the closure cap.
Fig. 5 is a vertical sectional view of the liner being flowed into the closure cap.
Figs. 6 and 7 are sectional and bottom plan views of another embodiment.

This invention relates to a unitary molded plastic closure cap which is applied to filled bottles or similar containers on high speed automatic sealing machines and which provides a satisfactory seal even at high pressures.
Prior tamperproof closures of this general type include metal closure caps such as aluminum caps where there is a cup-like sealing portion of the cap and usually an attached tamper indicating ring. These prior caps are applied to the filled bottles with complicated automatic machinery which applies the caps and which then must also crimp or otherwise deform the metal cap shells to interlock the tamper indicating band.
The present invention substitutes a unitary molded plastic cap for the metal closure and provides for both the sealing cup-like cap portion and when desired a unitary tamperproof or tamper indicating band.
A characteristic of the presently used metal caps is their ability to be applied to filled containers on high speed automatic sealing machinery. The closure cap of the present invention also has this advantage and provides for a high speed and low cost sealing machine application while at the same time providing a simple low cost plastic closure cap useful for high pressure sealing.
The closure cap 1 as illustrated includes a sealing means or liner 2 on the underside of the cap cover 3 for forming a tight seal between the cap 1 and the upper surface 4 of the bottle 5 finish 6.
A tamperproofing band 7 is attached to the lower edge of the cap skirt 10 by a number of relatively thin and rupturable bridges 9. The bridges 9 hold the tamper indicating band 7 onto the sealing portion of the closure 1 during cap application and sealing until the bottle is opened for use and while remaining unruptured indicate that the cap seal has not been tampered with. The closure cap may also be used without a tamper indicator in which case the band is eliminated from the cap and the cap forming die.
The closure cap 1 has the molded cup-like sealing and bottle engaging portion comprising the cover 3 and a depending skirt 10. The skirt 10 includes container engaging threads 11 on its inner surface and preferably has knurls 12 on its outer surface to facilitate cap removal. The cap 1 is formed of suitable plastic such as polypropylene, polyethylene, polystyrene or similar plastics.
The sealing liner 2 is preferably flowed in so that it covers the underside of the cap cover 3 and has a thickened outer edge 14 in inter-locking engagement with a channel 15 formed at the corner between the cap cover 3 and the cap skirt 10. The lower side 16 of the channel 15 is the upper surface 17 of a circular bead 18. The bead 17 preferably has a generally triangular cross- section with its inner-most edge or apex 18 being rounded in the form of a radius and with its upper liner engaging surface 17 forming about a 30 degree angle with the horizontal. The properties of the preferred sealing liner 2 plastic, which is polyvinylchloride or PVC, as it is flowed into a rotating closure 1 by a nozzle 21 (Fig. 5) cause it to have a thickened outer edge of the Channel 15 forming both an adhesive and a physical interlock between the liner 2 and the Channel 15. The above described taper of about 30 degrees for the upper surface 17 of the bead 18 assists to retain the liner 2 and also facilitates the stripping of the molded closure cap 1 shell from the molding tools during the shell molding portion. The taper of bead 18 tends to slightly flare the molded cap skirt 10 during the stripping to faciliate the withdrawal of the groove forming portion of a die as well as the thread forming portions.
Fig. 2 illustrates the sealing liner 2 of the closure cap 1 in engagement with the rim 4 of a sealed bottle 5. The bottle rim 4 has penetrated into the liner 2 causing an extrusion or build-up of the liner sealing portion around both the outer and inner edges 19 and 20 of the bottle rim 4. This inter-action between the liner 2 and the bottle 5 at the channel 15 perfects the seal between the liner 2 and the bottle rim 4 and forms tight seals which are effective even for relatively high pressures within the sealed bottles such as is the case with beers and sodas.
As already indicated, the closure cap may be used with a tamper indicating band or without such a band.
Figs. 1-3 illustrate one form of band which includes the container engaging band 7 and which has a number of bridges or gates 9 which attach the band 7 to the cap skirt 10. When the cap is removed from the bottle 5 this band tears loose and remains on the bottle 5 indicating that the cap has been turned upwardly.
Another form of band may be used such as is described in U.S. Patent No. 4,299,328, dated November 10, 1981. That form of band 22 (Fig. 4) on a cap 23 has a strapping action which insures the retention of the tamper indicating band 22 on a bottle. Two diametrically spaced lugs 24 on the band 22 hold the band on the bottle and provide a strapping action on removal in combination with a pair of bridge groups 25 each about 90° displaced from the lugs 24.
Figs. 6 and 7 illustrate an improved embodiment of a strapping type of tamper indicating band 26 on a cap 27. The band 26 includes approximately diametrically spaced lugs 28 to provide the strapping forces. In addition, the band 26 has several bridges 29 positioned about 90° away from the lugs 28 and a stronger bridge or hinge 30 positioned approximately diametrically opposite to the bridge 29. Additionally a notch 31 is provided in the band 26 adjacent to the hinge 30. In this embodiment of the closure cap, a removal of the cap 27 first snaps the band 26 at the notch 31 and then tears the bridges 28. This gives an immediate indication of closure tampering. During the final removal of the cap 27, the hinge 30 does not tear but remains intact lifting the tamper band 26 off of the bottle with the closure cap 27. Such a removable band is desired for certain sealing applications.
It will be seen that an improved molded unitary closure cap has been described which is readily manufactured and which is applied using existing high speed bottle sealing machinery to form excellent seals useful at high and low pressures.
As various changes may be made in the form, construction and arrangement of the parts herein without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Claims

A generally cylindrical molded plastic closure cap (1) for sealing a threaded container (5) with high pressure contents and having a disc-like cover (3) with a depending generally cylindrical skirt (10) with container engaging threads (11) on said skirt, a radially inwardly extending circular bead (18) being positioned on said skirt (10) between said cover (3) and said threads (11) forming a liner retaining groove (15) and a disk-like flowed-in plastic sealing liner (2) being positioned on the underside of said cover (3) and having its greatest thickness at its outer edge for forming a top and side seal with the container and occupying substantially the entire groove (15), characterized in that said bead (18) has a generally triangular cross section with the triangle base at the skirt (10) exceeding the triangle height on radial dimension and the triangle apex having a circular shape in the form of a radius and the bead (18) uppermost surface (17) having about a 30 degree angle with the cover for facilitating mold stripping and liner retention, and that said liner (2) has a progressively lesser width radially inwardly of the closure cap cover (3) with its minimum width being approximately one half of its greatest width.