Closure caps

Abstract

A cap for a container closure or closure plug includes a cap top having a top surface and a bottom surface, and an attachment ring extending axially downward from the bottom surface of the cap top under a central portion of the cap top. The attachment ring is securingly engageable with a container closure or closure plug. The attachment ring includes a cam surface extending radially outward from the attachment ring, where the cam surface deflects the attachment ring radially inward upon engagement of the attachment ring with the container closure or closure plug. The cap top and the attachment ring are connected by at least one frangible connection and at least one permanent connection, where the at least one permanent connection retains the cap top in one piece upon breaking of the at least one frangible connection for removal of the cap from the container closure or closure plug.

Claims

1. A cap for a container closure or closure plug, the cap comprising: a cap top having a top surface and a bottom surface; and an attachment ring extending axially downward beneath the bottom surface of the cap top under a central portion of the cap top, the attachment ring being securingly engageable with a container closure or closure plug, wherein the attachment ring comprises a cam surface extending radially outward from the attachment ring, the cam surface being configured to deflect the attachment ring radially inward upon engagement of the attachment ring with the container closure or closure plug, and wherein the cap top and the attachment ring are connected by at least one frangible connection and at least one permanent connection, the at least one permanent connection being configured to retain the cap in one piece upon breaking of the at least one frangible connection for removal of the cap from the container closure or closure plug.

2. The cap of claim 1, wherein the cam surface is configured to be securingly engageable with the container closure or closure plug.

3. The cap of claim 2, wherein the attachment ring has a snap-fit engagement with the container closure or closure plug.

4. The cap of claim 3, wherein the cam surface is configured to be received within a locking groove of the container closure or closure plug.

5. The cap of claim 1, wherein the attachment ring comprises a top portion and a bottom portion, and the cam surface extends radially outward from the bottom portion of the attachment ring.

6. The cap of claim 5, wherein the at least one frangible connection is located at the top portion of the attachment ring.

7. The cap of claim 6, wherein the at least one permanent connection extends between the bottom portion of the attachment ring and a tear strip extending at least partially within the cap top.

8. The cap of claim 1, wherein the at least one frangible connection is configured to be broken upon attempted removal of the cap from said container closure or closure plug.

9. The cap of claim 8, wherein a visible tamper indication is left following breakage of the at least one frangible connection.

10. The cap of claim 1, wherein the at least one permanent connection comprises a tear strip extending at least partially within the cap top.

11. The cap of claim 10, wherein the tear strip is defined at least in part by side grooves in the top surface of the cap top.

12. The cap of claim 11, wherein the remainder of the top surface of the cap top outside of the tear strip is unbroken following tearing of the tear strip for removal of the cap.

13. The cap of claim 11, wherein the side grooves are membranous.

14. The cap of claim 11, wherein the side grooves continue as a pair of parallel frangible membranous grooves extending part-way down the attachment ring.

15. The cap of claim 14, wherein the pair of parallel frangible membranous grooves extend part way down the attachment ring from a portion of the permanent connection which connects the attachment ring to the tear strip.

16. The cap of claim 14, wherein the pair of parallel frangible membranous grooves, when torn, weaken the attachment ring to permit removal of the attachment ring from the container closure or closure plug.

17. The cap of claim 1, wherein the force required to disengage the attachment ring from the container closure or closure plug is greater than the force required to break the at least one frangible connection.

18. A combination comprising a container, a closure plug and an overseal cap, the combination comprising: the container comprising an upstanding neck; the closure plug connected to the container, the closure plug comprising: a bottom wall; a sidewall configured to engage with the upstanding neck of the container; and a plurality of lugs extending axially upward from the bottom wall, each of the plurality of lugs comprising a radially inwardly facing guide surface and a locking groove at a base of each lug; the overseal cap comprising: a cap top having a top surface and a bottom surface; and an attachment ring extending axially downward beneath the bottom surface of the cap top under a central portion of the cap top, wherein the attachment ring comprises a cam surface extending radially outward from the attachment ring, the cam surface being receivable within the locking groove at the base of each lug whereby the attachment ring is securingly engageable with the closure plug, wherein the cam surface is configured to deflect the attachment ring radially inward upon engagement of the attachment ring with the radially inwardly facing guide surface of the closure plug, and wherein the cap top and the attachment ring are connected by at least one frangible connection and at least one permanent connection, the at least one permanent connection being configured to retain the overseal cap in one piece upon breaking of the at least one frangible connection for removal of the overseal cap from the closure plug.

19. The combination of claim 18, wherein the radially inwardly facing guide surface of the closure plug comprises a top portion and a bottom portion, the bottom portion extending radially inward relative to the top portion.

20. The combination of claim 19, wherein the bottom portion of the radially inwardly facing guide surface of the closure plug comprises an upper flank which slopes radially inward in a downward direction.

21. The combination of claim 18, wherein the upstanding neck of the container comprises internal threads and the sidewall of the closure plug comprises external threads that are configured to be threaded with the internal threads of the upstanding neck to engage the closure plug with the upstanding neck of the container.

22. The combination of claim 18, wherein the attachment ring comprises a top portion and a bottom portion, and the cam surface extends radially outward from the bottom portion of the attachment ring.

23. The combination of claim 18, wherein a visible tamper indication is left following breakage of the at least one frangible connection.

Description

DESCRIPTION OF THE DRAWINGS

(1) The above and further features of the present invention are illustrated, by way of example, the following description and drawings; wherein:

(2) FIG. 1 is a vertical cross sectional view of a prior art closure combination;

(3) FIG. 2 is an enlarged fragmentary sectional view of the plug wrench engaging lug of the closure plug of FIG. 1;

(4) FIG. 3 is a top plan view of the closure plug of FIG. 1;

(5) FIG. 4 is a plan of a tamper-evident cap in accordance with an embodiment of the invention;

(6) FIG. 5 is a section on the line V-V of FIG. 4;

(7) FIG. 6 is a section on the line VI-VI of FIG. 4;

(8) FIG. 7 is a sectional underplan of the cap of FIG. 4;

(9) FIG. 8 is an elevational detail illustrating the frangible and tear strip connections between the cap top and the attachment ring of the cap of FIG. 4; and,

(10) FIGS. 9a,b,c are perspective views showing the removal of the cap of FIG. 4 from a container neck.

SPECIFIC DESCRIPTION

(11) A tamper-evident cap in accordance with an embodiment of the present invention is illustrated by FIGS. 4 to 9 and consists of an imperforate cap 23 moulded of synthetic plastic resin having a disc-like top 24 surrounded by a peripheral depending skirt 25. An attachment ring 26 depends from the central portion of the cap top 24 and terminates at its bottom rim 27 in a radially outwardly projecting flange 28 having a radial cam surface 29. The attachment ring 26 is designed as a snap-fit within closure plug 6; in use cam surface 29 meets the closure plug lugs 12 and deflects/distorts the ring radially inwardly sufficiently for the ring to pass within the lugs and the ring flange 28 to snap-engage as a tight fit in the locking groove 17.

(12) The cap 23 and the attachment ring 26 are formed as a single moulding with the ring axially separated from the cap top 24 by a series of frangible links 30 and an essentially non-frangible or permanent connection 31. As shown more clearly in FIG. 8 each link 30 comprises an integrally moulded post 32 upstanding from the attachment ring top rim 33 with the upper end of each post 32 integral with and frangible from the lower surface of cap top 24. In the embodiment, there is a circular series of eight frangible links 30 between the cap top 24 and the attachment ring 26.

(13) A tear-strip 34 extends diametrically of the central region 35 and part way across cap top 24, above and within the circle of frangible links 30, and is formed by a pair of parallel frangible membranous side grooves 36 in the cap top 24 with a further frangible membranous cross groove 37 linking grooves 36 at one end of tear strip 34. As can be seen in FIGS. 6 and 8, the permanent connection 31 links the end of the tear strip adjacent to cross groove 37 to the attachment ring 26. The frangible grooves 36 continue as a pair of parallel frangible membranous grooves 39 extending from the permanent connection 31 and part-way only down the attachment ring 26; such that this region of the attachment ring 29 forms an integral extension 30 of the tear-strip 34. This integrity is due to the geometry of the cap top tear strip grooves 36, the permanent connection 31 and the attachment ring tear strip grooves 36.

(14) The upper surface of the cap 23 is unbroken and essentially flat, save for the membranous grooves 36, 37 and 38. This enables the cap 24 both to seal a container closure or closure plug, functioning as a capseal, and enables text such as advertising matter, logos, etc. to be applied to or printed on the upper surface of the cap with little or no distortion.

(15) The cap 23 can be fitted to the closure plug 6 simply by pressing the cap down onto the closure plug; this can be achieved manually or by use of a specially shaped tool (not shown). There is no need to align the cap attachment ring with the closure plug lugs.

(16) In use and as illustrated by FIGS. 9a,b,c, removal or attempted removal of the cap 23 from the closure plug 6 will fracture the links 30 and frangible grooves 36, 37 the tight-fit snap-fit engagement between the attachment ring and the closure plug 6 being stronger than the tear strength of links 30 and grooves 36, 37 so that the force required to disengage the attachment ring 26 from the closure plug 6 is greater than that required to fracture links 30 and grooves 36, 37. As the cap 23 is lifted off the closure plug, the cap top 24 will detach from the attachment ring 26 and the tear strip 34, leaving a visible, tamper-evidencing, rectangular aperture 41 in the cap top centre region 35. The cap top 24 will remain relatively moveably connected to the attachment ring 26 by the tear-strip 34; top end 38 of tear strip 34 forming part of cap top 24 whilst the bottom end of tear strip 34 and permanent connection 31 forms part of the attachment ring 26.

(17) Continued removal of the cap top from the closure plug will tear the attachment ring grooves 39, leaving an aperture in the ring wall that permits of deflection/distortion of the attachment ring 26, to enable the ring flange 28 to disengage from the closure plug locking groove 17. Cap top 24 and attachment ring 26 will remain connected together after removal from the closure plug.

(18) Cap skirt 25 is attached, as illustrated in Document EP-A-0725013, to the cap top 24 by a series of frangible ties 43 and includes an integral strap 40 between the skirt and the cap top; an integral tab 45 extends radially outwardly from the skirt. In use and as shown by FIGS. 9a,b and c, the tab is pulled upwardly to fracture the ties 43 so that the skirt 25 forms a ring handle attached by strap 40 to the cap top 24 to assist removal of the cap from the closure plug 6.

(19) The present invention has been illustrated with reference to caps snap-fitted to closure plugs, but it can provide a permanent connection for any cap having frangible means of attachment to a container, wherein a frangible connection can extend between the attachment means and the cap top.