US3438528A - Tamper-indicating closure - Google Patents

Description

April 15, 1969 M. R. FIELDS 3,438,528

TAMPER- INDICATING CLOSURE Filed Aug. 4, 1967 3 f I u 4 I /3 i i 5! Ill,

- 27 Imam-o: MACK 'Ews Arr-vs.

United States Oflice 3,438,528 Patented Apr. 15, 1969 3,438,528 TAMPER-INDICATWG CLGSURE Mack R. Fields, Lighthouse Point, 1312., assignor to Roehr Metals & Plastics Company, a limited partnership of Connecticut Filed Aug. 4, 1967, Ser. No. 658,419 Int. Cl. B65d 41/20, 55/02 US. Cl. 215-42 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to container closures, and more particularly to closures of so-called tamper-indicating type.

It is an object of this invention to provide an improved tamper-indicating closure of the type that has a tamperindicating skirt joined to the lower end of the closure sidewall at a frangible zone of weakness and in which the skirt is retained by cooperation with a bead or other part on the container so that upon unscrewing the closure for the first time, the closure will fracture at the zone of weakness and thereby indicate previous tampering with or removal of the closure from the container.

In the preferred form of the improved closure of this invention, the skirt telescopes with an annular bead or transfer ring on the container and is bonded thereto by a suitable adhesive. The transfer ring is substantially circular but the skirt is oval or elliptically shaped and with its short inside diameter being less than the maximum diameter portion of the bead. The long inside diameter of the skirt is greater than the maximum diameter portion of the head. When the closure is screw-threaded onto the container with adhesive having been coated onto the inner surface of the skirt, the skirt will expand and pass over the bead and maintain contact therewith in the regions of the short diameter portions of the skirt. Thus, despite variations in dimensions between the bead and skirt, there will always be adhesive extending across the gap therebetween in the region of the short diameter of the skirt and in regions adjacent thereto, even where a very thin layer of adhesive is employed.

It is a further object of this invention to provide a tamper-indicating closure of the type stated in which the adhesive may be used to form a mechanical lock between the skirt and bead without having to adhere to both. The skirt may have keyways consisting of radial holes, and/ or the bead may have keyways consisting of outwardly opening notches. The adhesive will flow into each keyway and from a mechanical lock between the skirt or the head as the case may be.

The attainment of the above and further objects of this invention will be apparent from the following description taken in conjunction with the accompanying drawing forming a part thereof.

In the drawing:

FIG. 1 is a sectional view, partially broken away, of the closure taken along the longitudinal axis thereof and showing the closure mounted on the neck of a container;

FIG. 2 is a fragmentary sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a fragmentary sectional view, on an enlarged scale, taken along line 3-3 of FIG. 2;

FIG. 4 is a sectional view similar to FIG. 2 and showing a modified form of the invention;

FIG. 5 is a sectional view similar to FIG. 2 and showing a further modified form of the invention;

FIG. 6 is a sectional view similar to FIG. 2 and showing a still further modified form of the invention; and

FIG. 7 is a fragmentary sectional view, on an enlarged scale, taken along line 7-7 of FIG. 6.

Referring now in more detail to the drawing, wherein like reference characters indicate like parts throughout, 1 designates a tamper-indicating cap having a body 2 that is formed of a unitary piece of molded plastic. Polyethylene or a commercial grade high-impact strength polystyrene may be used. The cap body 2 includes an end wall 3 and a cylindrical sidewall 5, the outer surface of which may be knurled to facilitate a grip thereon. The sidewall 5 is also formed with an internal thread 6 which cooperates with an external thread 7 that is formed on the cylindrical neck 9 of a container 10, which may be a glass bottle.

Axially intermediate the thread 6 and end Wall 3 the sidewall 5 has an internal annular lip 11 which cooperates with the end wall 3 to form a recess for receiving a sealing disc 13 which seals against the rim of the bottle neck 9 to seal the opening thereat when the cap 1 is in its closed position on the neck 9.

Adjacent to the free end 14 of the sidewall 5 there is an annular skirt 15. The skirt 15 is integrally molded with the cap body 2 and is joined to the free end 14 at a zone of weakness of the material of which the cap is molded. In the present form of the invention there are four circumferentially spaced frangible bridges 17.

The skirt 15 is thinner than the sidewall 5 and is of an oval shape. As seen in FIG. 2, the skirt 15 has a short inner diameter from 18 to 19 and a long inner diameter from 21 to 22. It will be noted too that the bridges 17 are not equally spaced but are closer to the long diameter region of the skirt 15, being preferably each about thirty degrees from point 21 or 22, as the case may be. When the cap 1 is threaded onto the neck 9 the skirt 15 telescopes with an annular bead 23 that is formed on the container neck 9 axially spaced from the thread 7. Where the container is a glass bottle, the head 23 may be the transfer ring that is used to handle the bottle after removal thereof from the mold. The diameter of the bead 23 measured across its radially outermost part 25 is approximately uniform but it may be slightly out of round, Within manufacturing tolerances. The short diameter of the skirt 15 is less than the bead diameter at 215 while the long diameter of the skirt 15 is greater than the bead diameter at 25. The skirt 15 is, however, sufliciently resilient within its elastic limits so that it expands at the short diameter regions '18, 19 when the skirt 15 passes over the head 23.

Prior to threading the cap 1 onto the container neck 9, the inner periphery 26 of the skirt 15 is coated with an adhesive 27. When the cap is threaded onto the container neck 9, there will be a surface-to-surface contact with the short diameter regions 18, 19' of the inner periphery 26 and the bead 23 at the peak portion 25 thereof. The adhesive 27 will adhere to the skirt and bead and form a bond that spans the gap between the head 23 and the skirt 15 at least in the regions of the short diameter portions of the skirt. The thickness of the layer of adhesive 27 will increase as the circumferential distance from the short diameter regions of the skirt increases. In the regions of the long diameter of the skirt, the adhesive may not be, and need not be, of suflicient thickness to span the gap between the skirt and bead.

When the cap 1 is initially unthreaded from the container neck 9, the adhesive bond between the skirt 15 and bead 23 will retain the skirt against movement. The resulting unscrewing torque applied to the cap will cause the bridges 17 to rupture, the ruptured bridges thereby indicating that the cap has been removed or loosened from its sealed position.

The containers and caps are subject to dimensional tolerances during manufacture of each. For example, commercial glass bottles are manufactured to certain tolerances recognized by the manufacturers. Plastic caps are subject to closer tolerances. The maximum permissible short diameter of the skirt 15 should be less than the minimum permissible diameter of the container bead at 25. Likewise, the minimum long diameter of the skirt 15 should be such that there will be some clearance thereat between a bead of maximum permissible diameter at 25 so that the maximum diameter parts of the skirt can contract as the minimum diameter parts expand during passage of the skirt over the container bead. Furthermore, it should be noted that by placing the bridges 17 nearer to the maximum diameter parts of the skirt than to the minimum diameter parts thereof, the stresses on the bridges are lessened as the skirt 15 flexes during passage over the bead 23.

In connection 'with this invention it will be appreciated that if the skirt and bead were both of uniform diameter there may be situations wherein a skirt with the largest permissible diametral tolerance will be telescoped over a bead of minimum permissible diametral tolerance. In that case the clearance between the two may be so great that the film of adhesive will not span the gap between the two and form a bond therebetween. Likewise, in a situation wherein the diameter of the bead at 25 is greater than the internal diameter of the skirt 15, there may be such interference between the skirt and bead as to cause rupture of the bridges as the rotating and axially moving skirt passes over the bead during mounting of the cap onto the container neck. By having the skirt oval shaped, as hereinbefore described, a bond between the skirt and bead is assured without rupturing the bridges 17 despite dimensional tolerances which may be expected between the two.

FIG. 4 shows a modified form of the invention 'which is similar to the construction previously described except that the skirt 15 has a number of circumferentially spaced keyways comprising radial holes 29 located opposite the portion 25 of the bead 23 when the closure is mounted onto the container neck 9. The adhesive 27 will flow into these keyways 29. In this form of the invention the ad hesive 27 need not adhere to the skirt 15 because the bond of the adhesive to the bead 23 results in a mechanical lock between the bead 23 and skirt 15.

FIG. 5 shows a further modified form of the invention which is similar to the construction shown in FIGS. l-3 except that the bead 23 has a number of circumferentially spaced keyways 31 comprising notches which open radially outwardly toward the skirt 15. Adhesive 27 will flow into at least some of the notches 31, particularly those in the region of the short diameters 18, 19 of the skirt 15. In this form of the invention the adhesive adheres to the skirt but need not adhere to the bead 23. It forms a mechanical lock between the skirt 15 and head 23.

FIGS. 6 and 7 show a further modified form of the invention which embodies features shown in both FIGS. 4 and5 in that the skirt 15 has the radial holes 29 and the bottle bead 23 has the notches or keyways 31. The adhesive 27 will flow into notches 31 and holes 29 at least in the region of the short diameter portions of the skirt 15. In this form of the invention adhesive need not adhere to either the head 23 or to the skirt 15 because the presence of the adhesive in both the holes 29 and the notches 31 results in a mechanical lock between the skirt 15 and bead 23.

The precise construction herein shown is illustrative of the principles of the invention. What is considered new and sought to be secured by Letters Patent is:

1. A tamper-indicating closure member in combination with a container having a member that forms an opening into the container, cooperating means on said members for mounting the closure member on the container memher and removing the closure member therefrom by rotational and axial movement of one member relative to the other member, said closure member having a wall dis posed about said container member, a skirt connected to said wall by means forming a rupturable zone of Weakness, said skirt being telescoped with a part of said container, the inner periphery of said skirt having a portion with one dimension measured from the axis of said rotational movement which is less than a dimension of the outer peripheral portion of said closure part as measured from said axis, said inner periphery also having a portion of another dimension measured from said axis that is greater than said dimension of said outer peripheral portion, said skirt being sufliciently resilient within its elastic limits to enable it to pass over said container part and maintain, at the region with said one dimension, contact with said outer peripheral portion when the closure member is mounted on said container member, and adhesive means for securing said skirt to said container part such that the application of torque on one of said members in a direction and of a magnitude sufficient to separate them causes rupture of the closure at said zone of weakness, said inner periphery and said outer peripheral portion being surfaces that are contoured to permit separation of one member from the other without rupture of said Zone of weakness in the absence of said adhesive means when the closure member is in closed position on the container member.

2. A combination according to claim 1 in which said inner periphery is oval-shaped and has opposed portions with said one dimension and opposed portions with said other dimension.

3. A combination according to claim 1 in which the adhesive means is bonded to said skirt and to said outer peripheral portion at least in the region of said one dimension.

4. A combination according to claim 1 in which said skirt has at least one keyway and the adhesive means extends into the keyway and is bonded at least to said outer peripheral surface.

5. A combination according to claim 1 in which said container part is peripherally recessed to form at least one keyway and the adhesive means extends into said keyway and is bonded at least to said skirt.

6. A combination according to claim 1 in which said skirt has at least one keyway, said container part is peripherally recessed to form at least one keyway and the adhesive means extends into the keyways.

7. A combination according to claim 6 in which the adhesive means is free from adherence with either said skirt or said container part.

8. A tamper-indicating closure in combination with a container having a member that forms an opening into the container, cooperating means on said member for threading the closure member on the container member and for removing the closure member therefrom, said closure member having a wall disposed about said container member, a skirt connected to said wall by means forming a rupturable zone of weakness, said skirt having a non-circular inner peripheral portion and being telescoped with a radial bead on said container, said bead and skirt having, when the closure member is mounted on said container member, circumferentially spaced re gions where said radially inner peripheral portion of the skirt and the adjacent peripheral portion of said bead are in close juxtaposition, and other circumferentially spaced regions where said peripheral portions are in more remote juxtaposition, and adhesive means at least adjacent to said regions of close juxtaposition securing the skirt to said container part.

9. A combination according to claim 8 in which said adjacent peripheral portion of the bead is of substantially uniform diameter, the inner peripheral portion of said skirt is oval-shaped and has a short diameter which is less than said diameter of said adjacent peripheral portion, and the regions of close juxtaposition are at said short diameter.

6 References Cited UNITED STATES PATENTS 12/1945 Blackman 215-42 X 5 GEORGE E. LOWRANCE, Primary Examiner.

US. Cl. X.R.

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