Child resistant closure assembly

Abstract: The closure assembly of Figures 1 and 3 comprises a container (1), a cap (2) having a skirt portion (3), and a captive band (4) attached via a tamper-evident tear-off band (5) and a pair of frangible connections (6 and 7) to the skirt portion (3). Arrows 8 on the skirt (3 and 9) on the container (1) show that the cap (2) has been put on in the aligned position. A tab (10) on one end of the tear-off band (5) provides a grip for the fingers in removing the band. In Figure 3 the tab (10) has been torn away to reveal a detent means on the container neck in the form of a projection (11). This is partly situated in a gap under the tab (10) before this has been lifted away, and partly under the start end of the tear-off band (5), which is adapted to flex slightly to accommodate the projection (11) without any significant damage to the frangible connections (6 and 7). If an attempt is made to remove the cap (2) in the aligned position, before the frangible connections (6 and 7) have been torn, the lower surface (11a) of the projection will be brought into abutment with an upwardly directed surface (4a) of captive band (4), which constitutes a detent means on the captive band, so resisting removal of the cap (2).

Description: BACKGROUND TO THE INVENTION This invention relates to a child resistant closure assemblies comprising a co-operating container and cap in which anti-rotation means must be overcome to enable the cap to be rotated to a predetermined angular orientation on the neck of the container (this position being referred to herein as 'the aligned position') at which one side of the cap (referred to herein as the 'front of the cap') can be pushed off the neck in order to open the container. In such closure assemblies the cap comprises a top wall and a depending skirt, and a co-operating circumferential bead and a lug are provided which engage to prevent the container from being opened, except at the aligned position. At the aligned position the lug, which is on the inside of the skirt at the front of the cap or on the neck of the bottle, can pass though a gap in the circumferential bead which is located on the neck of the container or inside the skirt at the front of the cap, so enabling the front of the cap to be pushed off the neck of the container in order to open the container. Closure assemblies as described above are referred to herein as closure assemblies of the kind described. In closure assemblies of the kind described, further engageable means are typically provided on the opposite side of the cap ('the rear of the cap') which disengage from the container neck on opening, so enabling the cap to be completely removed from the container. However, said further engageable means could be replaced, for example, with hinge means which attach the cap permanently to the container. The present invention relates particularly, but not exclusively, to a closure assembly of the kind described which is the subject of our European patent application published as EP 0500265. In this closure assembly, the further engageable means are provided on the rear of the cap and which disengage from the container neck on opening, to enable the cap to be completely removed from the container, and the skirt of the cap is connected by a number of breakable webs to a circumferentially extending tear-off band which in its turn is joined by further breakable webs to a continuous circumferentially extending captive band on the neck of the container. Lugs on the captive band and on the neck of the container engage to provide the anti-rotation means of the closure assembly. In this closure assembly the anti-rotation means prevent the cap from being rotated to the aligned position until the captive band has been disconnected from the cap by removal of the tear-off band, and removal of the band is tamper-evident. Provision of the anti-rotation means in closure assemblies of the kind described is an additional child-resistant safety feature to that of arranging for the cap to be removable only in the aligned position. However, these child-resistant safety features may be compromised in random instances of capping in the factory, if it is possible for the cap to be put onto the container already in the aligned condition, since it could then be possible for a child to remove the cap without difficulty. Moreover, where there is a tear-off band, it may be possible to replace the cap without damaging the tear-off band, thereby overcoming the tamper-evidence normally provided by such a band. In the closure assembly which is the subject of our European patent application published as EP 0500265, there is still some significant child-resistance in instances of capping in the aligned position, since, until the tear-off band has been removed, the tear-off band and the captive band make the cap less flexible, and add to the depth of the skirt, so making it difficult to push up the front of the cap to open the container. Nevertheless, development work has been undertaken to increase the child-resistance of the closure assembly should capping occur in the aligned position, and to promote tamper-evidence in such a situation. The present invention arises from this development work. According to the present invention, we provide a child-resistant closure assembly comprising a co-operating container and cap, the cap comprising a top wall and a depending skirt, and a co-operating circumferential bead and a lug are provided which engage to prevent the container from being opened, except at a pre-determined relative angular orientation of the cap and neck at which the lug, which is on the inside of the skirt at the front of the cap or on the neck of the bottle, can pass through a gap in the circumferential bead which is located on the neck of the container or inside the skirt at the front of the cap, so enabling the front of the cap to be pushed off the neck of the container in order to open the container, the assembly further comprising separable means attached to a lower edge of the skirt (3) of the cap of the assembly by way of a frangible connection, the neck and the separable means being provided with inter-engageable lugs which prevent relative rotation of the cap and neck until the frangible connection has been broken, characterised in that the assembly comprises detent means on the separable means and on the neck of the container of the assembly, surfaces of the detent means being engageable in said pre-determined orientation to resist the cap being pushed off the neck of the container until the frangible connection has been broken, the detent means on the neck of the container comprising one or more projections, said one or more projections comprising a rib which extends around the neck of the container through less than a quarter of the neck circumference. Preferably breaking of the frangible connection is arranged to be tamper-evident. It may, for example, involve the removal of a tear-off band, the absence of which would be clearly visible. Said separable means may itself comprise such a tear-off band, but most preferably comprises a band such as a captive band which is spaced from the cap by a tear-off band. The detent means on the neck of the container conveniently comprises a projection. Most preferably a surface of the projection is obliquely angled relative to the direction of capping of the container, in order to facilitate passage of the separable means over the projection without damaging the frangible connection of the separable means. In a preferred embodiment of the invention the detent means on the neck of the container comprises a projection in the form of a rib which extends around the neck through less than a quarter of the neck circumference. The detent means on the neck may comprise a plurality of projections disposed around the neck. Where the neck of the container is injection moulded, the detent means on the neck is preferably provided on a circumferential bead on the neck. Where the cap is provided with a tear-off band, the detent means on the neck of the container is desirably located in a gap between the ends of the tear-off band when capping has occurred in the aligned position. Where the detent means on the neck is disposed underneath a portion of a tear-off band, the tear-off band is preferably arranged to deform over the detent means without damaging its connection or connections to other parts of the closure assembly. BRIEF DESCRIPTION OF THE DRAWINGS By way of example only, specific embodiments of the invention applied to the closure assembly which is the subject of our European patent application published as EP 0500265 will now be described with reference to the accompanying drawings in which: Figure 1 is a front view of such a closure assembly according to the present invention in which the cap has been put on in the aligned position, Figure 2 is a front view of the closure assembly of Figure 1 in which the start of the tear-off band has been lifted to reveal detent means in the form of a projection on the container neck, Figure 3 is a front view of the container assembly of Figure 1 in which the cap and the tear-off band have been removed, leaving behind a captive band on the neck, Figure 4 is a front view of part of the container of Figure 1, showing the neck finish of the container, Figure 5 is a partial plan view of the container of Figure 1 showing the neck finish of the container, Figure 6 is a side view of the neck of the container shown in Figure 4 according to a first embodiment of the invention, Figure 7 is an enlargement of part of Figure 6, Figure 8 is a side view of the neck of the container shown in Figure 4 according to a second embodiment of the invention, Figure 9 is an enlargement of part of Figure 8, Figure 10 is a front view of part of the container according to a third embodiment of the invention, showing the container with an injection-moulded neck finish, Figure 11 is a plan view of the neck finish of Figure 10, Figure 12 is a plan view of a modified closure assembly in which the cap, tear-off band, and captive band have been removed, and Figure 13 is a fragmentary side view in section and showing, in area XIV, a fragmentary front view of the assembly container. In the figures, like reference numerals refer to like features and components. DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS The closure assembly of Figure 1 comprises an injection-moulded container 1, a cap 2 having a skirt portion 3, and a captive band 4 attached via a tamper-evident tear-off band 5 and a pair of frangible connections 6 and 7 to the skirt portion 3. Arrows 8 on the skirt 3 and 9 on the container 1 show that the cap has been put on in the aligned position. The container 1 may be blow-moulded, at least in part. A tab 10 on one end of the tear-off band 5 provides a grip for the fingers in removing the band. In Figure 2 the tab 10 has been lifted away from the surface of the container neck and partly torn away to reveal a detent means on the container neck in the form of a projection 11. This is partly situated in a gap under the tab 10 before this has been lifted away, between the ends of the tear-off band 5, and partly under the start end of the tear-off band 5, which is adapted to flex slightly to accommodate the projection 11 without any significant damage to the frangible connections 6 and 7. In this example, the projection 11 comprises a rib which extends around the neck of the container 1 through less than a quarter of the neck circumference. If an attempt is made to remove the cap in the aligned position, before the frangible connections 6 and 7 have been torn, the lower surface 11a of the projection will be brought into abutment with an upwardly directed surface 4a of captive band 4, which constitutes a detent means on the captive band, so resisting removal of the cap. Resistance is also offered when the cap 2 is non-aligned. Figure 3 shows the closure assembly after the tear-off band 5 has been torn away and the cap removed, leaving the captive band 4 on the neck. A lug on the cap normally engages beneath circumferential bead 13 on the container neck to prevent removal of the cap, except in the aligned position in which the lug can pass through the gap 14 in the bead. The term 'captive band' is normally used to refer to a band which passes continuously around the neck of a container, but which is left behind after removal of a tear-off band. In this instance, after having been left behind, the captive band has no further role, and is free to fall off the neck of the container should the container be inverted. Figure 4 shows the neck finish when the captive band 4 has also been removed. Lugs 12 on the neck, which are normally covered by the captive band, interengage with lugs on the inside surface of the captive band to form the anti-rotation means of the closure assembly. As can be seen from Figures 5 to 7, the projection 11 in one embodiment has sides which are substantially rectangular. However, in a second embodiment, shown in Figures 8 and 9, the projection is substantially wedge-shaped in vertical cross section, so as to present an obliquely angled surface 11b to the tear-off band 5 and the captive band 4 during capping, so that these can pass easily over the projection without damaging the frangible connections 6 and 7. In the embodiment of Figures 10 and 11, like reference numerals refer to similar parts to those of the embodiments of Figures 1 to 9. Since the container in this embodiment is injection moulded, the lower portion of the neck finish has a surface 15 of reduced diameter in proportion to that of the lower portion of the neck finish of the embodiments of Figures 1 to 9, to limit material mass and thereby improve the speed of moulding. However a land 16 is left in the form of a circumferential bead, which protrudes from surface 15 to a diameter where it lies closely adjacent to the inside surface of a tear-off band and corresponding in function to tear-off band 5 of the other embodiments. The projection 11 in this embodiment is provided on land 16. In Figures 12 and 13 a container 101 of an injection-moulded closure assembly is illustrated thereby, the container cap, tear-off band and captive band having been removed for reasons of clarity. Like the container 1 of Figures 1 to 11, the container 101 may be blow-moulded, at least in part. The container 101 is provided with detent means on the neck of the container, comprising three equi-spaced projections 111 disposed in a ring which is coaxial about the central longitudinal axis 25 of the container. A single gap 114 is provided in the circumferential bead 113. One of the projections 111 is aligned with the gap 114 when capping takes place. The non-illustrated container cap, the tear-off band and the captive band of the assembly are of substantially the same form as cap 2, tear-off band 5 and captive band 4 of Figures 1 and 2. The provision of the plurality of lugs 111, spaced apart around the neck of the container 101 are for three reasons. Firstly, the lugs 111 serve to prevent the captive band (not shown, but corresponding to captive band 4 of Figure 1) from falling off if the container, when opened, is inverted. Secondly, the plurality of spaced-apart lugs 111 serve to increase resistance to the container cap (not shown, but corresponding to cap 2 of Figure 1) being removed, particularly in the cap aligned position, when the tear-off band is present. Increased, that is, compared to the resistance provided by a single lug 11 of Figures 2 and 3. A single lug 11 offers resistance at a single, localised position, whereas the lugs 111 each offer substantially the same resistance, but at a number of spaced-apart positions. Thirdly, the spaced-apart lugs 111 assist machine-capping, as the cap is centralised as it sits on the three lugs 111, before being pushed down into place. Use of a single lug 11 can result in the associated cap assuming a tilted position before being pushed down into place, which is undesirable. Where possible, any of the features disclosed herein may be added to, or substituted for other features. For example, the single lug 11 of Figures 10 and 11 could be replaced by a plurality of lugs, as in Figure 12. Other modifications are possible. For example, containers of increased neck size may employ more than three lugs corresponding to lugs 111. Furthermore, lug dimensions, particularly width, may vary according to requirements.

Claims: A child resistant closure assembly comprising a co-operating container (1; 101) and cap (2), the cap comprising a top wall and a depending skirt (3), and a co-operating circumferential bead (13) and a lug are provided which engage to prevent the container from being opened, except at a pre-determined relative angular orientation of the cap and neck at which the lug, which is on the inside of the skirt at the front of the cap or on the neck (15) of the bottle, can pass through a gap (14) in the circumferential bead which is located on the neck of the container or inside the skirt at the front of the cap, so enabling the front of the cap to be pushed off the neck of the container in order to open the container, the assembly further comprising separable means (4, 5) attached to a lower edge of the skirt (3) of the cap (2) of the assembly by way of a frangible connection (6, 7), the neck (15) and the separable means (4, 5) being provided with inter-engageable lugs (12; 112) which prevent relative rotation of the cap and neck until the frangible connection has been broken, characterised in that the assembly comprises detent means (4a, 11a; 111a) on the separable means and on the neck (15) of the container (1) of the assembly, surfaces (4a, 11a; 111a) of the detent means being engageable in said predetermined orientation (8, 9) to resist the cap (2) being pushed off the neck of the container until the frangible connection has been broken, the detent means on the neck of the container comprising one or more projections (11, 111), said one or more projections comprising a rib (11) which extends around the neck of the container through less than a quarter of the neck circumference. A closure assembly as claimed in claim 1, wherein the surfaces of the detent means are also engageable in a non-aligned position of the cap (2) . A closure assembly as claimed in claim 1 or claim 2 wherein the frangible connection (6, 7) is arranged to be tamper-evident. A closure assembly as claimed in claim 3 wherein tamper evidence is apparent by the removal of a tear-off band (5). A closure assembly as claimed in any one of claims 1 to 4, wherein said separable means comprise a tear-off band (5). A closure assembly as claimed in claim 5, wherein the closure means comprise a band (4) which is spaced from the cap (2) by a tear-off band (5). A closure assembly as claimed in any of claims 1 to 6, provided with a plurality of said projections (111), distributed around the neck of the container (101) of the assembly in an equi-spaced manner. A closure assembly as claimed in any of the preceding claims wherein a surface (11b) of said one or more projections (11) is obliquely angled relative to the direction of capping of the container, in order to facilitate passage of the separable means (4, 5) over the projection (11) without damaging the frangible connection (6, 7) of the separable means. A closure assembly as claimed in claim 6, wherein the detent means on the neck of the container is located in a gap (14) between the ends of the tear-off band (5) when capping has occurred in said pre-determined orientation of the cap and neck. A closure assembly as claimed in claim 6 wherein the detent means (11) on the neck is disposed underneath a portion of the tear-off band. A closure assembly as claimed in claim 10, wherein the tear-off band (5) is arranged to deform over the detent means without damaging its connection or connections to other parts of the closure assembly.

Inventors: LOADER JOHN A, LOADER, JOHN A.
Applicants: REXAM CONTAINERS LTD, REXAM CONTAINERS LIMITED
Application year: 1996
Main classification: B65D50
IPC codes: B65D50