WO2001054999A1

WO2001054999A1 - Screw on container closures

Info

Publication number: WO2001054999A1
Application number: PCT/GB2001/000293
Authority: WO
Inventors: David Phillip Millson; Peter Rumford
Original assignee: Bericap Uk Limited
Priority date: 2000-01-26
Filing date: 2001-01-25
Publication date: 2001-08-02
Also published as: AU2866001A; GB2358626A; GB0001812D0

Abstract

A screw on container closure (30) comprises threads (24) which include ratchet formations (26) for co-operation with complimentary formations on a threaded container neck, the ratchet formations (26) allowing the closure to be screwed on to the neck but resisting unscrewing of the closure from the neck. Tamper indicating contents access means may be provided, for example in the form of a tear-out wall (34). A snap on re-closure cover (50, fig. 10) may be provided, for protection of the container contents once the wall (34) has been removed.

Description

SCREW ON CONTAINER CLOSURES

This invention relates to screw on container closures. It has particular advantages in the field of tamper indicating closures, although it is useful in relation to any screw on container closure designed to be relatively easy to apply, but relatively hard to remove.

A wide variety of tamper indicating arrangements are known for use in conjunction with screw on container closures. Many include a band or ring frangibly connected to a closure member. Locking formations on the band co-operate with complementary formations on the container neck so as to form a ratchet. As the container closure is screwed on, the locking formations slide over the complementary formations, allowing the closure to be fully tightened. However the locking and complementary formations co-operate to lock the band against rotation with respect to the container neck in the closure unscrewing direction. Thus, normally, an attempt to unscrew the closure from the container neck will break the frangible connections between the ring and the remainder of the closure.

Such tamper indicating arrangements are not completely secure. By careful manipulation of the ring and closure together, it may be possible to force the closure off the container neck against the action of the ratchet without any obvious signs of damage to the frangible connections. The container contents can therefore be accessed and the closure replaced without any signs that this has occurred.

GB2202215 discloses a container and threaded closure in which ratchet teeth are formed on the rim of a container neck, having ramp surfaces and intervening facets to form a serrated rim on the neck, for co-operation with corresponding teeth formed in the closure, so as to lock the closure into place.

US4533678 concerns a child resistant screw on safety cap for a container, of the type that must be pushed down to allow unscrewing. Co-operating locking abutments on the cap and container threads engage each other until the cap is depressed. We have sought an alternative a φroach to the protection of screw on container closures against unauthorised tampering. In accordance with the present invention, there is provided a screw on container closure having a body portion that is manually indivisible in normal use, the body portion comprising threads and ratchet formations for respective co-operation with complementary threads and formations on a container neck, the cooperating ratchet formations allowing the closure to be screwed on to the neck but resisting unscrewing of the closure from the neck, each body portion ratchet formation comprising a ramp surface, characterised in that the ramp surface extends obliquely across the radial depth of the thread, whereby the ramp surface has a radially inner end proximate to the body thread crest and a radially outer end proximate to the body thread root. Each body portion ratchet formation may further comprise a facet extending in a substantially radial plane, or between the radial plane and the plane of the ramp surface. We have found that this provides a particularly secure anti-tamper feature in that the closure may be readily applied to the container, but is very difficult to remove.

Access to the container contents must therefore be by means other than the threaded connection between the closure and container neck, such means being readily provided in a form allowing tamper indication, usually including elements which are broken or destroyed on opening. For example the closure or the container may be provided with a rupturable membrane or foil, or a line of weakness defining a tear open or tear out part. Conveniently, this access means is provided in the closure itself. A re-closable cover may be provided, to protect and prevent spillage of the container contents once the access means have been breached. Such a container closure is particularly suitable for liquid food products, such as milk or fruit juices. The closure may include an anti-drip pouring lip.

The ratchet formations may be recessed within a protruding part of the closure thread, or protrude from a recessed part of the closure thread, for co-operation with complementary formations formed in or on the container thread. Preferably the threads are multi-start threads and not all turns are provided with the ratchet formation. These plain turns ensure that threaded engagement is not lost whilst screwing the closure on. Alternatively, the respective formations on the container and closure may be provided offset to one end of the threads, preferably at a location where they are protected from tampering, e.g. by the top corner of the closure, or by a shoulder on the container neck, and /or by a stiffening band formed at a lower edge of the closure.

These and further preferred features of the invention are in the dependent claims or will be apparent from following description of an illustrative embodiment, made with reference to the drawings in which:

Fig 1 is a top plan view of a container neck embodying the present invention;

Fig 2 is a side view of the container neck of Fig 1;

Fig 3 is a part sectional view showing details of the container neck and ratchet mechanism; Fig 4 is a cross-sectional view of a container closure cap adapted to fit the neck of the preceding figures;

Fig 4a shows parts of Fig 4 on an enlarged scale;

Fig 5 is an underplan view of the closure cap of Fig 4;

Fig 6 is the side view of the closure cap of Fig 4; Fig 7 is a top plan view of a re-closure lid adapted to fit the closure cap of Fig 4;

Fig 8 is a side view of the lid of Fig 7;

Fig 9 is a cross-sectional view corresponding to Fig 8;

Fig 10 shows the re-closure lid of Fig 7 in place on the closure cap of Fig 4; and

Figs 1 1 and 12 show a further embodiment.

Referring to Figs 1 to 3, the container neck 10 includes a sidewall 12 provided with a four start external thread 14. A series of projecting ratchet formations 16 are formed in recessed areas of the thread, on two opposed sides of the neck. Each formation 16 comprises a ramp surface 18, and an adjacent facet 20 extending in a generally radial plane. The corresponding closure cap 30 shown in Figs 4 to 6 includes a complementary 4 start internal thread 22. Each turn 24 of the thread 22 include notches 26 at corresponding locations to the projecting formations 16 of the container neck 10. Each notch 26 comprises a ramp surface 28, and a facet 32 extending in a generally radial plane. The facets 20, 32 could instead extend in planes between the radial plane and the planes of the ramp surfaces 18, 28, so that the co-operating locking formations 16, 26 have undercut locking faces constituted by the facets 20, 32.

As the cap 30 is screwed onto the container neck 10, an opposed pair of turns 24 of the internal thread 22 ride up over the ramp surfaces 18 of the uppermost neck formations 16.

As the screwing on of the cap continues, the uppermost neck formations 16 become aligned with and snap into the leading notches 26. The abutting ramp surfaces 28, 18 can ride past each other, allowing the further screwing on of the cap. However, the abutting facets 20, 32 prevent the cap from being screwed off. Screwing on of the cap continues until all of the projecting formations 16 become engaged in corresponding notches 26 in the cap thread. The notches 26 in the other pair of turns of the cap thread do not engage any neck formations 16, but are present to ensure that the cap properly engages the neck threads when initially applied to the container neck in any rotational orientation. Only two sets of projecting ratchet formations 16 are provided on the neck 10 rather than four sets, so threaded engagement is not lost whilst screwing the cap on.

When fully screwed on, the cap is thus securely held on the container neck, with the abutting facets 20, 32 preventing it from being unscrewed. The cap sidewall, the internal threads 22, the projecting formations 16, and the neck sidewall 12 are all relatively stiff, so that the cap is very difficult to remove forcibly without causing obviously visible damage. Moreover the formations 16 and notches 26 are not readily accessible when the cap has been screwed on, and so are difficult to lever out of engagement.

For access to the container contents, a circular closure wall 34 is connected to the remainder of the cap along a peripheral line of weakness 36. The closure wall 34 may be torn out along the line of weakness using a ring pull 38, upstanding from the remainder of the closure cap 30. The closure cap is also provided with an anti-drip pouring lip 40. Suitable means, such as a depending lip 42, are provided for sealing the cap 30 to the container neck 10.

To further assist in making the cap easy to apply but difficult to remove, it is provided with exterior driving formations 44, Fig 6, engageable by hand or machine, and comprising ramp surfaces 46 and generally radially directed facets 48. These driving formations are more "slippery" when attempting to unscrew the cap, as compared to when they are used to screw it on.

As shown in Figs 7 to 10, the cap 30 is provided with a re-closure cover 50, used to protect the container contents after the closure wall 34 has been torn out. The cover 50 includes a depending internal sealing lip 52, provided at its lower end with a sealing bead 54, snap engageable over a corresponding bead 56 in the cap 30. The pouring lip 40 of the cap 30 also snap engages in an undercut 58 formed in the upper internal corner of the re-closure cover 50.

Figs 11 and 12 respectively show a closure 60 and corresponding container neck 62 forming another embodiment of the invention. Recessed ratchet formations 64 are provided adjacent to a lower end 66 of the closure, below threads 68. Complementary protruding ratchet formations are formed at the base of the container neck 62 adjacent to a shoulder 70 formed in the container, below threads 72. As the closure 60 is screwed onto the neck 62, the neck threads 72 ride past the recessed ratchet formations 64 and engage the closure threads 68. As the closure 60 is screwed fully home, the ratchet formations 64, 74 are brought into full locking engagement. The upper ends of the protruding formations 74 lie along a helical line spaced below the threads 72, so as not to interfere with the closure threads 68.

The closure lower rim 66 is thickened to provide greater stiffness. When the closure is fully tightened, the rim 66 lies closely adjacent to the shoulder 70 and is therefore difficult to pry away from the contain r neck 62, preventing disengagement of the ratchet formations 64, 74.

Various modifications will be readily apparent. For example, recessed ratchet formations could be exchanged for protruding formations and vice versa, in both illustrated embodiments. In Figs 11 and 12, instead of or in addition to the illustrated ratchet formations, protruding ratchet formations could lie inside the upper inner comer 76 of closure 60 for co-operation with complementary recessed ratchet formations formed around the distal end or rim of the neck 62. The comer 76 in this case imparts the required stiffness to the closure and prevents access to the unillustrated ratchet formations for prying them out of engagement.

Claims

1. A screw on container closure having a body portion (30) that is manually indivisible in normal use, the body portion comprising threads (22) and ratchet formations

(26) for respective co-operation with complementary threads (14) and formations (16) on a container neck (10), the co-operating ratchet formations (16, 26) allowing the closure (30) to be screwed on to the neck (10) but resisting unscrewing of the closure from the neck, each body portion ratchet formation (26) comprising a ramp surface (28), characterised in that the ramp surface (28) extends obliquely across the radial depth of the thread (14), whereby the ramp surface (28) has a radially inner end proximate to the body thread (14) crest and a radially outer end proximate to the body thread (14) root.

2. A closure as claimed in claim 1 characterised in that each body portion ratchet formation (26) further comprises a facet (32) extending in a substantially radial plane or between the radial plane and the plane of the ramp surface (28).

3. A closure as claimed in claim 1 or 2 characterised in that it comprises or is used in combination with a container comprising tamper indicating contents access means (34) comprising elements that are broken or destroyed on opening.

4. A closure or container and closure combination as defined in claim 3, characterised in that the access means (34) comprises a rupturable membrane or foil.

5. A closure or container and closure combination as defined in claim 3, characterised in that the access means (34) comprises a tear open or tear out part.

6. A closure or container and closure combination as defined in any of claims 3 - 5, characterised by a reclosable cover (50) for protection of the container contents once the access means have been breached.

7. A closure as defined in any preceding claim, characterised by exterior driving formations (44) comprising ramp surfaces (46) and substantially radially directed facets (48).

8. A closure as defined in any preceding claim, characterised in that the respective formations (16, 26) are incorporated into the respective threads (22, 14) on the closure (30) and neck (10).

9. A closure as defined in claim 8, characterised in that the closure ratchet formation (26) is recessed within a protruding part of the closure thread (22), or protrudes from a recessed part of the closure thread, for co-operation with a complementary formation formed in or on the neck thread (14).

10. A closure as defined in claim 8 or 9, characterised in that the threads (22, 14) are multi-start threads and not all turns thereof are provided with the ratchet formation.

11. A closure as defined in claim 7, characterised in that the respective ratchet formations (64, 74) on the container (70) and closure (60) are provided offset to one end of the threads (68, 72).

12. A closure as defined in any preceding claim, characterised by an anti-drip pouring lip.