EP3743351A1

EP3743351A1 - A child-resistant closure

Info

Publication number: EP3743351A1
Application number: EP19704551.1A
Authority: EP
Inventors: Stephen Faragher
Original assignee: Obrist Closures Switzerland GmbH
Current assignee: Obrist Closures Switzerland GmbH
Priority date: 2018-01-26
Filing date: 2019-01-25
Publication date: 2020-12-02
Anticipated expiration: 2039-01-25
Also published as: BR112020015171A2; MX2020007809A; EP3743351B1; CN111971234B; CN111971234A; WO2019145495A1; BR112020015171B1

Abstract

A child-resistant closure for a container is provided. The closure comprises outer (15) and inner (25) nested caps each having a top panel (16) and a side skirt (17) depending generally peripherally therefrom. The outer cap loosely generally encompasses said inner cap to allow relative rotary and axial movement therebetween. The outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position. The outer cap comprises a plurality of spring members (18) for urging the inner and outer caps axially away from each other to a second axial position. The inner cap comprises a top panel provided with a plurality of ramps (30), the spring members providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in a screwing direction, but slipping over the ramps freely in an unscrewing direction. Downward pressure on the outer cap is used to overcome the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations. The external surface of the inner cap side skirt includes a plurality of substantially full height axial ribs (20) for allowing venting when the outer and inner caps are initially assembled together. The inner cap drive formations comprise a plurality of castellations 34 which upstand from the inner cap top panel, and each full height axial rib connects to a castellation.

Description

A CHILD-RESISTANT CLOSURE

The present invention relates generally to child-resistant closures for containers. More particularly the invention relates to a child-resistant safety closure having an improved application/removal drive mechanism.

Child resistant safety closures comprising two nested closure members are well known. Typically, outer and inner cap members are provided with cooperating sets of lugs which engage each other when the outer closure is rotated in the direction to remove the closure from a container. A plurality of spring fingers on the inner surface of a top panel of the outer closure member urge the outer closure member away from the inner closure member and prevent engagement of the lugs. The outer surface of the top panel of the inner closure member is formed with ramps which are associated with the outer cap member spring fingers so that when the outer cap member is rotated relative to the inner cap member in a direction to apply the closure to a container the spring fingers engage the ramps to cause the cap members to rotate together. When the outer cap member is rotated in the opposite, or unscrewing, direction the spring fingers ride over the ramps to prevent accidental or unwanted removal of the closure. Only when the closure is rotated in the unscrewing direction and an axial force is simultaneously applied to the outer closure member the cooperating lugs are interengaged to unthread the inner closure member from the container.

The present invention seeks to provide improvements in or relating to such closures.

According to an aspect of the present invention there is provided a child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, the outer cap comprising a plurality of spring member for urging the inner and outer caps axially away from each other to a second axial position, the inner cap comprising a top panel provided with a plurality of ramps, the spring members providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in an screwing direction, but slipping over the ramps freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the

i external surface of the inner cap side skirt includes a plurality of full height axial ribs for allowing venting when the outer and inner caps are initially assembled together, in which the inner cap drive formations comprise a plurality of castellations which upstand from the inner cap top panel, and in which a said full height axial rib connects to each castellation.

The closure may further comprise a plurality of non-full height axial ribs provided on the inner cap sidewall and alternate with the full height ribs.

The castellations may be generally U-shape in plan.

The castellations may comprise a first radially extending side wall upstanding from the top panel and a second radially extending side wall upstanding from the top panel, said first and second side walls being located at or towards the periphery of the top panel and being mutually spaced, the first and second side walls are joined at one end by an arcuate cross wall.

The full height axial ribs may extend from the first side walls of the castellations.

The first side walls may be joined to the respective assembly ribs by an inclined wall section.

The castellations may be thinned in non-functioning areas.

The full height axial ribs may be mutually spaced around the external surface of the inner cap side skirt, and the circumferential extent of the ribs may be less than the circumferential extent of the spacing therebetween.

In some embodiments, for each ramp a respective detent projection is provided which projects above the plane of the top panel and lies in the path of travel of the spring member, the projection supports the spring member when in driving engagement with the ramp to resist deformation of the spring member as it transmits force to the ramp face, the profile of the projection matches the profile of the region of the spring member in contact therewith.

Each ramp may be generally wedge shape.

Each ramp may be generally trapezium-shape in plan.

In some embodiments, (substantially) immediately rotationally beyond each ramp an indentation is provided in the inner cap top panel. Each ramp may be profiled to support the spring member substantially continuously as the member passes over it in the unscrewing direction.

The profile of each ramp may change constantly as the ramp height increases.

Each ramp may have a variable section sweep with a section that varies as the ramp height increases.

Each ramp may therefore be a feature that sweeps along a specified trajectory

Each ramp may have a variable section sweep with a generally constant radius trajectory and a section that sweeps along the radius that constantly changes whereby the spring member/s are in maximum contact with the ramp through rotation.

The ramps may be profiled to support the spring member substantially continuously as the member passes over it in the unscrewing direction, in which the ramp has a variable section sweep with a generally constant radius trajectory and a section that sweeps along the radius that constantly changes whereby one or more spring members are in maximum contact with one or more ramps through rotation.

According to a further aspect of the present invented there is provided a child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member/s providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in an screwing direction, but slipping over the ramp/s freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the external surface of the inner cap side skirt includes one or more axial ribs for allowing venting when the outer and inner caps are initially assembled together. The external surface of the inner cap side skirt may include a plurality of full height axial ribs for allowing venting when the outer and inner caps are initially assembled together, in which the inner cap drive formations comprise a plurality of castellations which upstand from the inner cap top panel, and in which a said full height axial rib connects to each castellation.

In some aspects and embodiments the assembly rib is formed integrally with an inner cap drive formation. This can be used, for example, to strengthen the formation and may allow for lightweighting of the member by removing material.

The rib may connect to an edge of the drive formation which, in use, engages drivingly with a drive formation on the outer cap.

The rib may extend along substantially the entire length of the skirt.

Each drive formation on the inner cap may have a respective rib.

In some embodiments the periphery of the inner cap top panel is provided with a plurality of castellations.

The or each rib may connect to an edge of a respective castellation.

The castellations may be generally U-shape in plan.

The castellations may comprise a first radially extending side wall upstanding from the top panel and a second radially extending sidewall upstanding from the top panel, said first and second side walls being located at or towards the periphery of the top panel and being mutually spaced, the first and second side walls are joined at one end by an arcuate cross wall.

In some embodiments a said assembly rib extends from the said first side wall of each said castellation.

The first side wall may be joined to the assembly rib by an inclined wall section.

The castellations may be thinned in non-functioning areas. The ribs may be mutually spaced around the external surface of the inner cap side skirt, and the circumferential extent of the ribs may be less than the circumferential extent of the spacing therebetween.

According to a further aspect there is provided a child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member/s providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in an screwing direction, but slipping over the ramp/s freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which for the or each ramp a respective detent projection is provided which projects above the plane of the top panel and lies in the path of travel of the spring member, the projection supports the spring member when in driving engagement with the ramp to resist deformation of the spring member as it transmits force to the ramp face, the profile of the projection matches the profile of the region of the spring member in contact therewith.

According to a further aspect there is provided a child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member/s providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in an screwing direction, but slipping over the ramp/s freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the ramp is profiled to support the spring member substantially continuously as the member passes over it in the unscrewing direction.

The profile of the ramp may change constantly as the ramp height increases.

The present invention also provides an inner cap for a child-resistant container closure of the type comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, one of the inner and outer caps comprising one or more spring members for urging the inner and outer caps axially away from each other to a second axial position, the other of the inner and outer caps comprising one or more ramps, the spring member/s providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in an screwing direction, but slipping over the ramp/s freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the external surface of the inner cap side skirt includes a plurality of full height axial ribs for allowing venting when the outer and inner caps are initially assembled together, in which the inner cap drive formations comprise a plurality of castellations which upstand from the inner cap top panel, and in which a said full height axial rib connects to each castellation.

The present invention also provides an inner cap as described herein.

The present invention also provides an outer cap as described herein.

The present invention also provides a closure as described herein in combination with a container.

Different aspects and/or embodiments of the invention may be used separately or together.

Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with the features of the independent claims as appropriate, and in combination other than those explicitly set out in the claims.

The present invention will now be more particularly described with reference to, and as shown in, the accompanying drawings, in which:

Figure I is a plan view of a closure outer part formed in accordance with an embodiment of the present invention;

Figure 2 is a side elevation of the closure outer part of Figure I ;

Figure 3 is a perspective view of the closure part of Figures I and 2;

Figure 4 is an underside perspective view of the closure part of Figures I and 2;

Figures 5 to 9 show top, side, bottom, top perspective and bottom perspective views of the outer part of Figure I o 4;

Figure 10 is a perspective view of an inner part formed in accordance with an embodiment of the present invention;

Figure I I is an underside perspective view of the inner part of Figure 10;

Figures 12 to 16 show top perspective, top, side, bottom perspective and bottom views of the inner part of Figures 10 and I I ;

Figures I 7and 18 are magnified views of part of the inner cap illustrating assembly ribs and castellations; and

Figures 19 and 20 are magnified views of part of the inner cap illustrating a ramp.

Example embodiments are described below in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes herein described. It is important to understand that embodiments can be provided in many alternate forms and should not be construed as limited to the examples set forth herein. Accordingly, while embodiments can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included. Elements of the example embodiments are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate.

The terminology used herein to describe embodiments is not intended to limit the scope. The articles“a,”“an,” and“the” are singular in that they have a single referent, however the use of the singular form in the present document should not preclude the presence of more than one referent. In other words, elements referred to in the singular can number one or more, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, items, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, items, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be interpreted as is customary in the art. It will be further understood that terms in common usage should also be interpreted as is customary in the relevant art and not in an idealized or overly formal sense unless expressly so defined herein.

Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiments shown and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention.

The closure of this embodiment is made up of two components: an outer cap 15, shown in Figures I to 9 and an inner cap 25, shown in Figures 10 to 20.

The outer cap 15 is formed with a circular top panel 16 integrally moulded with a depending cylindrical skirt 17.

Formed on the underside of the top panel 16 and extending into the interior of the outer cap 15 are a plurality of finger-like spring members 18. The embodiment illustrated shows four curved, arcuate spring members 18, but as few as one or two members may operate satisfactorily, and more than four, such as six members may be employed if desired.

The spring members 18 take the form of inclined tabs integrally formed with the underside of the top panel 16. The spring members 18 are inclined at an angle of about 45 degrees with respect to the vertical axis of the outer member 10; however, the angle of inclination may be varied as long as a ratcheting function, to be described later, can be properly performed. It will also be noted that the spring members 18 are positioned radially inwards of the periphery of the panel 16. The fingers are curved along their length with generally the same radius of curvature as the sidewall 17.

In addition to the spring members 18, a plurality (eight, in this embodiment) of drive lugs 19 are also moulded into the underside of the top panel 16 and depend downwardly. The drive lugs 19 are located adjacent to the extreme outer portion of the inside diameter of the outer cap 15 adjacent the depending skirt 17. The drive lugs 19 then extend inwardly toward the springs 18 but their edges terminate before reaching the spring members 18. The illustration of eight drive lugs 19 is by way of example and a single drive lug would function properly; but multiple drive lugs may be preferred to allow a number of different removal engagement positions.

A retention bead 2 1 is moulded into the interior wall of the depending skirt 17 near the open end of the depending skirt 17. The bead 2 1 is continuous about the entire circumference of the depending skirt 17.

The outer cap 15 may be manufactured of any material sufficiently resilient to provide the necessary spring quality for the integrally moulded spring members 18, for example polyethylene or propylene.

The inner cap 25 is also formed as an integral unit having a circular top panel 26 and a depending skirt 27 attached thereto.

The interior of the depending skirt 27 is provided with a screw thread 28 for engagement with a threaded neck finish of a container (not shown).

On the outer surface of the side skirt 27 a plurality of full height assembly ribs 20 are provided.

The ribs 20 extend axially along the skirt and project outwardly therefrom. In this embodiment the ribs 20 extend along substantially the full height of the skirt 26.

In addition, a plurality of half (approximately) height ribs 22 are provided. In this embodiment the ribs 20 and ribs 22 are evenly distributed alternately around the skirt

The ribs 20, 22 allow for the venting of pressure build up as the inner and outer caps are assembled together (see below for further details). In addition, the ribs provide additional strength to support the edges of the drive lugs (castellations) used for engagement when unscrewing the closure. This additional strength allows, in this embodiment, for a thinning of the drive lugs in non-functioning areas.

The upper portion of the inner cap member 25 is of a general configuration that may be considered to be castellated. Spaced at intervals around the periphery of the top panel are upwardly or axially extending castellation-like drive projections 34. In the assembled closure, the drive lugs 19 on the interior of the outer cap 15 are sized such that they may mesh into the openings between the drive projections 34. This imparts a driving force to the inner cap member 25 so that it may be driven by the outer cap 15.

The top panel 26 is provided with a plurality (in this embodiment eight) upstanding castellations 34. Each castellation 34 comprises a first radially extending side wall 34a upstanding from the top panel and a second radially extending sidewall 34b upstanding from the top panel. The first and second side walls are located at the periphery of the top panel and are mutually spaced. The first and second side walls are joined at one end by an arcuate cross wall 34c.

An assembly rib 20 extends from a respective first side wall 34a. The assembly rib 20 connects to the edge of each of the castellation to provide extra strength to support the edge used for engagement when unscrewing. In this embodiment the first side wall 34a is joined to the assembly rib 20 by an inclined wall section 34d.

The ribs 20 therefore extend into and merge with the inner cap drive lugs, each connecting to the leading edge (i.e. the edge which is used to provide drive in use) of a respective castellated drive lug.

Weight is removed by thinning the castellation in non-functioning areas 60. The top panel 26 is also provided with four ramps 30. The ramps 30 are connected to the arcuate walls 34d of alternate castellations 34 by an extension part 36. The ramps are generally wedge-like, with a curved leading face 30a and a trailing abutment face 30b.

Behind (i.e. anticlockwise of) each ramp 34 is a shallow groove 3 I , depression, dent or the like.

The shape of the ramps 30 is designed and profiled so that they support the fingers 18 of the outer cap 15 during the entire time it is in contact with these features.

The ramp portion 30 is shaped and profiled so as to be sympathetic to the trajectory of the spring fingers as they pass over in use. The portion has a variable section sweep with a section that varies as the ramp height increases i.e. the ramp face is not flat. The trajectory of the portion has a constant radius; the section that sweeps along the radius is constantly changing (in both X and Y planes). This allows the spring finger to be in maximum contact with the ramp through rotation so that there is no time at which there is only a point contact between them. This allows for a ramp to be formed with the minimum amount of material whilst providing maximum contact with the finger during rotation.

A retention bead 35 is moulded into the exterior surface of the depending skirt 27. The retention bead 35 extends about the entire circumference of the depending skirt 27 and is of a diameter greater than that of the retention bead 2 1 formed in the depending skirt 17 of the outer cap 15. The ribs 20, 22 extend from the bead 35.

The inner cap 25 is an independent closure in itself for a container. The inner 25 therefore may be made of any suitable material and need not necessarily be made of the same material as that of the outer cap 15; a thermoplastic material such as polyethylene or polypropylene may, for example, be used.

The closure 10 is formed by assembling the outer cap 15 and the inner cap 25. To assemble the completed closure, the retention bead 2 1 is forced over the retention bead 35, in the process causing the depending skirt 17 of the outer closure cap member 10 to spring outwardly slightly. The assembly ribs 20 allows for the venting of pressure build-up as the inner 25 is assembled into the outer 15 (or vice versa).

Once the larger diameter retention bead 2 1 has passed over the retention bead 35, the depending skirt 17 springs back inwardly trapping the inner cap 15 within the outer cap 25. The fit between the outer cap 15 and the inner cap 25 is not tight. There is an appreciable gap between the interior of the depending skirt 16 and the exterior of the depending skirt 32. Thus, the outer cap 15 may both rotate and axially slide with respect to the inner cap 25.

In use the inner cap 25 is threadably engaged on an exteriorly threaded finish of a container. A sealing disk (not shown) may be provided in the inner cap 25 and will be trapped between the upper portion of the finish and the lower portion of the top panel of the inner cap 25.

When the outer cap 15 is rotated clockwise the spring members 18 are moved so as to become in driving engagement with respective faces 30b. Thus, the completed closure may be screwed onto the finish of a container, since the rotation of the outer cap 15 will cause the spring members 18 to drivingly engage the ramps 30 and consequently turn the outer cap 15 and the inner cap 25 as a unit in the tightening direction.

Conversely, it may be seen that if the outer cap 15 is rotated in the opposite direction or the direction normally unscrewing the cap from the container, the springs 18 slip over the ramps 30. The profile of the ramp 30 changes constantly as the ramp height increases. This allows for maximum support to be provided to the spring fingers 18.

Thus, these two functions provide a one-way ratchet drive for the inner cap 25. The outer cap 15 thus can rotate freely with respect to the inner cap 25 in the unscrewing direction. It is this feature which makes the closure child-resistant, since it is impossible to unscrew the combined closure without an additional motion.

In this embodiment the ramps 30 are shaped and profiled so that they support the edge/tip of the spring fingers 18 during substantially the entire time they are in contact with these features.

To remove the closure from a container finish, the outer cap 15 must be compressed downwardly over the inner cap 25.

The spring members 18 serve normally to keep the outer cap 15 and the inner cap 25 in their axially spaced relationship, in which removal of the closure from the container is impossible. However, utilising the spring function of the springs 18, the outer cap 15 may be pressed downwardly over the inner cap 25. The downward displacement of the outer cap 15 brings the drive lugs 19 into engagement with the spaces between the drive castellations 34. Alignment of the drive lugs 19 and the spaces between the drive projections 34 may not be perfect at the time the outer cap 15 is pressed downwardly. However, slight rotation of the outer cap 15 in the loosening direction will bring these members into proper drive engagement. With the drive lugs 19 properly engaged, the outer cap 15 may be rotated and the inner cap 25 will rotate with it as a unit through this driving engagement.

Once the combined closure is removed from the container and the downward pressure on the outer cap 15 is released, the combined closure will spring back under the influence of the spring member 18, thereby placing the closure in configuration suitable for reapplication. The user may then screw the closure back onto the container finish utilising the driving engagement of the springs 18 and the ratchet faces 30b.

Once back on the container, the combined closure may not be removed again without the downward compression of the outer cap 15 over the inner cap 25. When a child attempts to remove the assembled closure from a container without pressing downwardly on the outer cap 15, an audible warning sound is produced. The springs 18 slipping over the ratchet lugs 29 and hitting the top panel 26 produces a loud and distinctive“clicking” sound. This sound may be heard for some distance and can serve as a warning to parents that children are tampering with a container whose contents may be harmful to them.

The closure of this invention assembled from the outer cap 15 and the inner cap 25 may be applied by conventional capping machinery, since there is no need for any manipulation of the closure during the tightening procedure.

Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiments shown and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

Claims

I . A child-resistant closure for a container, the closure comprising outer and inner nested caps each having a top panel and a side skirt depending generally peripherally therefrom, said outer cap loosely generally encompassing said inner cap to allow relative rotary and axial movement there between, the outer and inner caps having corresponding drive formations which can be brought into driving engagement when the caps are moved axially towards one another to a first axial position, the outer cap comprising a plurality of spring member for urging the inner and outer caps axially away from each other to a second axial position, the inner cap comprising a top panel provided with a plurality of ramps, the spring members providing a biasing force to maintain said outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in an screwing direction, but slipping over the ramps freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring finger bias to move the caps to the first axial position to allow unscrewing of the closure using the inner and outer cap drive formations, in which the external surface of the inner cap side skirt includes a plurality of substantially full height axial ribs for allowing venting when the outer and inner caps are initially assembled together, in which the inner cap drive formations comprise a plurality of castellations which upstand from the inner cap top panel, and in which each full height axial rib connects to a castellation.

2. A closure as claimed in claim I , further comprising a plurality of non-full height axial ribs are provided on the inner cap sidewall and alternate with the full height ribs.

3. A closure as claimed in claim I or claim 2, in which the castellations are generally U- shape in plan.

4. A closure as claimed in claim 3, in which the castellations comprise a first radially extending side wall upstanding from the top panel and a second radially extending side wall upstanding from the top panel, said first and second side walls being located at or towards the periphery of the top panel and being mutually spaced, the first and second side walls are joined at one end by an arcuate cross wall.

5. A closure as claimed in claim 4, in which the full height axial ribs extends from the first side wall.

6. A closure as claimed in claim 5, in which the first side wall is joined to the assembly rib by an inclined wall section.

7. A closure as claimed in any preceding claim, in which the castellations are thinned in non-functioning areas.

8. A closure as claimed in any preceding claim, in which the full height axial ribs are mutually spaced around the external surface of the inner cap side skirt, and in which the circumferential extent of the ribs is less than the circumferential extent of the spacing therebetween.

9. A closure as claimed in any preceding claim, in which for each ramp a respective detent projection is provided which projects above the plane of the top panel and lies in the path of travel of the spring member, the projection supports the spring member when in driving engagement with the ramp to resist deformation of the spring member as it transmits force to the ramp face, the profile of the projection matches the profile of the region of the spring member in contact therewith.

10. A closure as claimed in any preceding claim, in which each ramp is generally wedge shape.

I I . A closure as claimed in any preceding claim, in which each ramp is generally trapezium- shape in plan.

12. A closure as claimed in any preceding claim, in which immediately rotationally beyond each ramp an indentation is provided in the inner cap top panel.

1 3. A closure as claimed in any preceding claim, in which each ramp is profiled to support the spring member substantially continuously as the member passes over it in the unscrewing direction.

14. A closure as claimed in any preceding claim, in which the profile of each ramp changes constantly as the ramp height increases.

15. A closure as claimed in any preceding claim, in which each ramp has a variable section sweep with a generally constant radius trajectory and a section that sweeps along the radius that constantly changes whereby the spring member/s are in maximum contact with the ramp through rotation.

16. A closure as claimed in any preceding claim, in which the ramps are profiled to support the spring member substantially continuously as the member passes over it in the unscrewing direction, in which the ramp has a variable section sweep with a generally constant radius trajectory and a section that sweeps along the radius that constantly changes whereby one or more spring members are in maximum contact with one or more ramps through rotation.

17. A closure as claimed in any preceding claim in combination with a container.