WO2002053472A1

WO2002053472A1 - Tamper evident push-pull closure

Info

Publication number: WO2002053472A1
Application number: PCT/AU2001/001680
Authority: WO
Inventors: Brian Feldham
Original assignee: Plaspak Closures Pty Ltd
Priority date: 2000-12-28
Filing date: 2001-12-28
Publication date: 2002-07-11
Also published as: AUPR233100A0; NZ523640A

Abstract

A liquid container closure (1) having an internally screw threaded skirt (1a) including a tamper band (2); a drinking spout (4) having a push-pull cap; an overcap with an annular skirt adapted to completely cover the cap releasably securable to the closure or cap, the annular skirt including at its lower extremity an inwardly extending protrusion co-operating with an outwardly projecting protrusion at the closure shoulder (12) to releasably secure the overcap on the closure, a second tamper band frangibly attached to the skirt and including ramped teeth interacting between the band and the closure shoulder (12) permitting one way rotation but preventing opposite rotation. The shoulder (12) includes an upstanding wall spaced radially outwardly from the tamper band to permit the teeth to ride over each other during assembly of the overcap but not so as to facilitate insertion of objects under the tamper band between the tamper band and closure.

Description

TAMPER EVIDENT PUSH-PULL CLOSURE

The present invention relates to tamper evident push-pull closures and in particular to a push-pull closure of the type which is intended to be screw threaded onto a liquid container and having an overcap associated with the closure which overcap overlies the push-pull valve and is endowed with its own tamper evident connection to the closure.

For a number of years liquid containers have been available with what are commonly termed "push-pull" type closures. These closures typically comprise a closure with a depending internally threaded skirt affixed to a container usually involving a tamper band under the skirt. The push-pull cap atop the closure is in fact a push-pull type valve which facilitates dispensing of liquid, often by inverting the container and placing the user's mouth about the cap once the cap is pulled slightly up from the closure. The valve may be readily re-sealed by pushing the movable cap axially back down against the closure.

As the user's mouth is often placed about the push-pull cap controlling the valve it is desirable that this cap be covered prior to use by an overcap and furthermore as the purpose of ihs push-pull valve is to facilitate consumption of the liquid contents of the container at a number of different times it is desirable that the overcap be replaceable after initial removal. It is additionally desirable that the overcap is provided with a tamper evident feature adjacent those parts where it meets the closure as otherwise it would be pointless having a tamper evident feature between the cap and container alone.

Closures having the dual tamper evident feature abovernentioned have been proposed in the past although they suffer from various defects. Some such closures permit breaking of the initial tamper evident seal between the closure and the overcap by counter-clockwise twisting which may also unscrew the closure from the container seal thereby resulting in leaking of the container during use. Other tamper evident seals are expensive to produce, unreliable in operation or alternatively may be circumvented relatively easily.

It is consequently an object of the present invention to ameliorate one or more of the abovernentioned disadvantages with prior art push-pull closures or at least to provide the market with an alternative.

According to the present invention there is provided a closure for a liquid container having an internally screw threaded skirt; a tamper evident feature on the skirt adapted to interact with a complementary container; a spout atop the closure having a cap thereover movable from a first position whereat the cap prevents dispensing of liquid through the spout to a second position whereat the cap permits the dispensing of liquid through the spout; an overcap with an annular skirt adapted to completely cover the cap in at least the first position; the overcap being releasably securable to the closure or cap; the lower extremity of the annular skirt of the overcap being provided with an annular tamper band affixed thereto by frangible means; the annular tamper band having on its radially internal facing surface one or more internally directed protrusions adapted to underlie a radially outwardly directed protrusion on the closure so as to prevent removal of the tamper band f om the closure after initial application; a wall upstanding from the closure radially outwardly of the overcap tamper band adapted to prevent insertion of objects beneath the tamper band between the tamper band and the closure so as to prise the temper band therefrom; radially externally directed teeth on the closure beneath the radially outwardly directed projection and radially inwardly directed teeth on the inside of the tamper band both sets of teeth being ramped so as to permit the teeth to ride over each other in the event of rotation of the overcap and attached tamper band with respect to the closure in a first direction but to engage each other upon rotation of the tamper band in the opposite direction with respect to the closure thereby causing breakage of the frangible bridges between the overcap and the tamper band; the annular wall upstanding from the closure being radially outwardly spaced from the tamper band by a distance which will permit the two sets of teeth to ride over each other during said counter-clockwise movement of the overcap but not by such - a distance so as to facilitate insertion of objects under the tamper band between the tamper band and closure.

One embodiment of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a longitudinal section through a closure in accordance with the present invention;

Figure 2 is a longitudinal section through an overcap for the closure of figure 1;

Figure 3 is a part longitudinal sectional view through the closure and overcap of figures 1 and 2; and

Figure 4 is a cross-sectional view through X-X' of figure 3.

Figure 1 depicts in longitudinal cross section a closure 1 in accordance with the present invention having an internally threaded skirt portion la with a first tamper band 2 therebeneath and attached thereto by frangible bridges 3 in the conventional manner. The upper portion of the closure includes a spout 4 having openings 5 in the top thereof about a central upper disk 6. The abovernentioned features are typical of closures incorporating push-pull type valves. The valves also incorporate a cap (not shown) adapted to move longitudinally up and down the vertical sides 7 of spout 4 from a first raised position (not shown) whereat liquid can pass through openings 5 and out a further aperture (not shown) in the central portion (not shown) of the cap (not shown) to a second lowered position whereat the top (not shown) of the cap (not shown) obstructs openings 5. Once again these features are typical of push-pull type closures currently available.

In order that the cap (not shown) may be rendered tamper proof prior to sale and also in order to provide protection for the cap after initial use but prior to the container carrying the closure being discarded an overcap 8 is provided as depicted in figure 2. This overcap 8 is intended to overlie the cap (not shown) and spout portion 4 of the closure 1.

As depicted in figure 2 the overcap is provided with a long annular skirt portion 9 depending from upper disk portion 10 and the lower extremities of the skirt portion 9 are attached by frangible bridges 10 to a second annular tamper band 11.

The lower extremities of second tamper band 11 are intended to seat adjacent shoulder portion 12 of closure 1 as is best viewed in figure 3. The shoulder portion 12 of closure 1 is depicted in enlarged section in figure 3. The shoulder portion occurs due to the increase in the diameter of the closure at skirt portion la over and above the diameter of spout 4. The shoulder portion 12 in fact is comprised of two steps 13 and 14 each including a horizontal and vertical face. The horizontal face 15 of step 13 is intended to underlie the bottom of the cap (not shown) whereas the horizontal portion 16 of step 14 is intended to underlie the bottom portion 17 of overcap 8 and serve as a rest therefor. Step 14 includes horizontal surface 16 and vertical surface 16a.

With further reference to figure 3 frangible bridges 10 are depicted maintaining second tamper band 11 adjacent overcap 8. The underside 18 of the lower portion of second tamper band 11 sits directly above horizontal surface 19.

Second tamper band 11 is retained on closure 1 by way of an annular radially outwardly directed annular protrusion 20 adjacent the upper extremity of vertical surface 16a of step 14. This protrusion 20 cooperates with radially inwardly directed annular protrusion 20a extending radially inwardly from an upper portion of tamper band 11. It will be observed that radially inwardly directed protrusion 20a underlies radially outwardly directed protrusion 20 to achieve locking of the second tamper band 11 onto the closure after initial apphcation of the overcap 8 with attached tamper band 11 to closure 1. In order to prevent unauthorised removal of overcap 8 from closure 1 without breaking of bridges 10 by insertion of a sharp object between the lower extremity 18 of tamper band 11 and horizontal surface 19 of the closure annular wall 21 is provided on the closure 1 above skirt la. Annular wall 21 lies well beneath annular protrusion 20 and extends up only to about half-height of vertical surface 16a. in this embodiment the top of the wall stands approximately 1.3 millimetres above horizontal surface 19 whereas the full height of vertical surface 16a is 2.75 millimetres measured from horizontal surface 19 to horizontal surface 16. It has been found that when wall 21 is spaced at a distance of approximately 0.5 mnlimetres from the radially outward vertical face 22 of second tamper band 11 it is adequate to prevent insertion of sharp articles between lower surface 18 of second tamper band 11 and horizontal surface 19 of the closure and therefore serves to prevent unauthorised jacking of the second tamper band 11 (with overcap 17) off closure 1.

In order to achieve conventional removal of overcap 17 from about the closure, cap and spout clockwise rotation of. the overcap is required. When clockwise rotation of the overcap occurs ramped radially inwardly directly teeth 22 on second tamper band 11 engage ramped radially outwardly directed teeth 23 on vertical surface 16a of closure 1. It will be observed that teeth 22 and 23 are provided with ramped surfaces 24 as well as steeply angled faces 25 configured in a manner such that opposing steeply angled surfaces 25 will engage each other upon clockwise rotation of the overcap 8 (and attached tamper band 11). This arrangement permits only limited clockwise movement of overcap 8 with respect to closure 1 before continued attempts to rotate the overcap with respect to the closure cause fracture of frangible bridges 10. Fracture of frangible bridges 10 leaves the second annular tamper band 11 captive about closure 1 due to the interaction of annular protrusions 20 and 20a. Overcap 8 is thereafter free of the closure save for any securing means which may be provided to facilitate re-attachment of the overcap to the cap or closure.

In order that counter-clockwise rotation of the overcap may not result in fracture of frangible bridges 10 it is important firstly that the tamper band 11 have sufficient flexibility to move radially outward such that ramped surfaces 24 may override each other and furthermore it is important that wall 21 be sufficiently radially outwardly spaced from the equilibrium outer diameter of second tamper band 11 so as to accommodate radially outward expansion of the tamper band during such overriding without the tamper band binding against the radially internal surfaces of wall 21.

The provision of sufficient flexibility in the tamper band may be achieved by regulating the thickness of the tamper band and/or ensuring that at certain arcs of the tamper band there are no teeth corresponding to externally directed teeth on the closure.

If for example there were eighteen externally directed teeth on the closure all radially spaced from each other at equal intervals then it may be desirable to have internally directed teeth on the tamper band spaced at corresponding arcs with the exception of four locations whereat two teeth may be omitted. The omission of the teeth allows the tamper band to stretch into a more linear shape over those areas where a tooth has been omitted thereby helping to accommodate external displacement of the remaining teeth as they override externally directed teeth on the closure. If for example eight such teeth were omitted from the tamper band the arrangement of teeth on the tamper band would be such that there would be four groups of either two or three teeth on the tamper band with teeth within each group at the same radial spacings with respect to each other as those on the closure each group of teeth on the band would be separated from each other by an arc of tamper band whereat the spacing of adjacent teeth was trebled. Naturally there are a number of arrangements of teeth which would achieve the same result and for example a lesser number of teeth on the closure as compared with the tamper band would achieve the same result. A sufficient number of teeth on the tamper band must however be capable of being brought into contact with teeth on the closure so as to ensure breaking of the frangible bridges 10 during clockwise rotation of the overcap with respect to the cap as if too few teeth are in register then outward expansion of the tamper band may permit the two sets of teeth to override each other even during clockwise rotation.

It will be appreciated that the overriding of teeth which permits counterclockwise rotation of the overcap with respect to the closure ensures that attempts to remove the overcap from the closure will not result in unscrewing of the closure from the container provided the container closure threading is in accordance with the usual convention.

It is intended that alternate embodiments apart from that above may be devised without departing from the scope and intendment of the present invention.

Claims

The claims defining the invention are as follows;

1. A closure for a liquid container having an internally screw threaded skirt; a tamper evident feature on the skirt adapted to interact with a complementary container; a spout atop the closure having a cap thereover movable from a first position whereat the cap prevents dispensing of liquid through the spout to a second position whereat the cap permits the dispensing of liquid through the spout; an overcap with an annular skirt adapted to completely cover the cap in at least the first position; the overcap being releasably securable to the closure or cap; the lower extremity of the annular skirt of the overcap being provided with an annular tamper band affixed thereto by frangible means; the annular tamper band having on its radially internal facing surface one or more internally directed protrusions adapted to underlie one or more radially outwardly directed protrusions on the closure so as to prevent removal of the tamper band from the closure after initial application; a wall upstanding from the closure radially outwardly of the overcap tamper band adapted to prevent insertion of objects beneath the tamper band between the tamper band and the closure so as to prise the tamper band therefrom; radially externally directed teeth on the closure beneath the radially outwardly directed projection and radially inwardly directed teeth on the inside of the tamper band both sets of teeth being ramped so as to permit the teeth to ride over each other in the event of rotation of the overcap and attached tamper band with respect to the closure in a first direction but to engage each other upon rotation of the tamper band in the opposite direction with respect to the closure thereby causing breakage of the frangible bridges between the overcap and the tamper band; the annular wall upstanding from the closure being radially outwardly spaced from the tamper band by a distance which will permit the two sets of teeth to ride over each other during said counterclockwise movement of the overcap but not by such a distance so as to facilitate insertion of objects under the tamper band between the tamper band and closure.

2. A closure in accordance with claim 1 hereof wherein there is one annular radialy outwardly directed protrusion on the closure.

3. A closure in accordance with claim 1 hereof wherein there is one annular radialy inwardly directed protrusion on the tamper band.

4. A closure in accordance with claim 1 hereof wherein the first direction of rotation of the overcap and attached tamper band with respect to the closure is counter clockwise when viewed from above ; the closure itself being provided with a standard thread requiring anti-clockwise motion to unscrew it from a complementary container.

5. A closure in accordance with claim 1 hereof wherein the top of the wall upstanding from the closure terrninates at a height beneath the radialy outwardly directed protrusion on the closure.

6. A closure in accordance with claim 1 hereof wherein the height of the radialy externally directed protrusion measured from the base of the wall is at least 70 per cent greater than that of the wall.

7. A closure in accordance with claim 1 hereof wherein the height of the wall is between 1 and 2.5 mm.

8. A closure in accordance with claim 1 hereof when the height of the wall is between 1.1 and 1.7 mm.

9. A closure in accordance with claim 1 hereof wherein the height of the radialy externally directed protrusion from the closure measured from the base of the wall is between 2.5 and 3.5 mm.

10. A closure in accordance with claim 1 hereof wherein the wall is spaced at between 0.35 and 0.65 mm from the radialy outermost surface of the overcap tamper band.

11. A closure in accordance with claim 1 hereof wherein the number and configuration of teeth on the closure and overcap tamper band is such as to permit limited rotational movement of the overcap with respect to the closure without separation of the overcap tamper band.

12. A closure in accordance with claim 1 hereof wherein the number and configuration of teeth on the closure and overcap tamper band is such that not all teeth at come in to register with each other at the same time during initial application of the overcap thereby preventing excessive radialy outward flexing of the overcap tamper band such as would bring it into of obstructive contact with the wall standing marginally radialy outwardly thereof.

13. A closure in accordance with claim 1 hereof wherein the number and configuration of teeth on the closure and overcap tamper band is such that no more than a quarter of a turn is necessary during removal of the overcap to sever the overcap tamper band; no more than 75 per cent of the teeth being in register with each other at any one time.

DATED this 27th day of December 2001.

PLASPAK CLOSURES PTY LIMITED by their Patent Attorneys Barker Blenkinship & Associates