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 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.

The present invention provides 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 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 comprising a plurality of spring members for urging the inner and outer caps axially away from each other to a second axial position, the inner cap top panel being 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 capable of drivingly engaging the ramps in the second axial position so as to drive the outer and inner caps together in a screwing-on direction, but slipping over the ramps freely in an unscrewing direction, downward pressure on the outer cap overcoming the spring member 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 inner cap top panel is provided with capture features for ensuring contact between the spring members and the ramps during driving engagement of spring members with ramps in the screwing-on direction.

Capture features may be provided as part of each ramp (e.g. formed internally therewith).

Some embodiments provide or relate to an improved child resistant mechanism by adding a capturing feature to the side of the ramp. This improves the function by capturing the flexible “finger” feature on the outer component of the closure assembly.

The capturing feature to the side of the ramp makes sure that there is solid contact between the finger and the ramp. This improves the child resistance performance of the closure.

Capture features may be configured to prevent spring fingers from deforming around ramps during screwing on of the closure onto a container.

Each ramp may have a capture feature to the side thereof.

In some embodiment the ramps are generally Z-shape. In some embodiments for each ramp a capture feature is provided.

The spring members may, for example, be formed as spring fingers.

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 a ramp face in the screwing-on direction. The profile of projections may match the profile of the region of a spring member in contact therewith.

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.

In some embodiments 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 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.

Each ramp may be generally wedge shape.

In some embodiments, rotationally beyond each ramp an indentation is provided in the inner cap top panel.

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. The inner cap drive formations may 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 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 light-weighting 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.

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

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.

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.

A child-resistant closure formed in accordance with the present invention is shown in Figure I and is generally indicated 10.

The closure 10 is made up of two components: an outer cap 15 (Figure 2); and an inner cap 20 (Figure 3, shown “upturned”).

The outer cap 15 is formed, in this embodiment, as a single piece with a generally circular top panel 16 and a depending cylindrical skirt 17.

As shown in Figure 4, formed on the underside of the outer cap top panel 1 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 fingers 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 cap 15; 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 1 . 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 (four, in this embodiment) of generally elongated U-shape drive dogs 19 are also formed (e.g. moulded) into the underside of the top panel 1 and depend downwardly. The drive dogs 1 are located adjacent to the extreme outer portion of the inside diameter of the outer cap 15 adjacent the depending skirt 17. The drive dogs 19 then extend radially inwardly toward the springs 18 but their edges terminate before reaching the spring members 18. The illustration of four drive dogs 19 is by way of example and a single drive dog would function properly; but multiple drive dogs may be preferred to allow a number of different closure removal engagement positions.

A retention bead 23 is moulded into the interior wall of the depending skirt 17 near the open end of the depending skirt 17. In this embodiment the bead 23 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 20 is also formed as single piece having a generally circular top panel 26 and a depending cylindrical 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 21 are provided. The ribs 21 extend axially along the skirt and project outwardly therefrom.

In this embodiment the ribs 21 extend along substantially the full height of the skirt 27.

In addition, a plurality of half (approximately) height ribs 22 are provided. In this embodiment the ribs 21 and ribs 22 are evenly distributed alternately around the skirt 27

The ribs 21 , 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 21 provide additional strength to support the edges of drive dogs (castellations) used for engagement when unscrewing the closure, as described below. This additional strength allows, in this embodiment, for a thinning of the drive dogs in non-functioning areas.

The upper portion (closed end) of the inner cap 20 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 dogs 19 on the interior of the outer cap 15 are sized such that they can mesh into the circumferential gaps/openings between the drive projections 34. This imparts a driving force to the inner cap 20 so that it may be driven in the unscrewing (anti-clockwise) direction by the outer cap 15. A cylindrical rim 25 upstands from the periphery of the top panel (coaxial with, and in some ways a continuous of, the side skirt 27).

The top panel 26 is provided with a plurality (in this embodiment four) upstanding castellations 34. Each castellation 34 comprises a first radially extending sidewall 34a portion upstanding from the rim 25 and a second radially extending sidewall portion 34b upstanding from the rim 25. The first and second sidewalls portions 34a, 34b are mutually spaced and joined at one end by an arcuate cross wall 34c.

Assembly ribs 21 extend from respective first sidewall portions 34a. The assembly ribs 21 connect to the edge of each of the castellations 34 to provide extra strength to support the edge of the sidewall portions 34b used for engagement when unscrewing.

The ribs 21 therefore extend into and merge with the inner cap drive castellations, each connecting to the leading edge (i.e. the edge which is used to provide drive in use) of a respective castellation.

Weight is removed by thinning the castellation in non-functioning areas 60.

The top panel 26 is provided with four ramps 30.

Each ramp 30 comprises a lead-in minor ramp portion 31 , a major ramp portion 32 and a capture leg 33.

In this embodiment the major ramp portions 32 are connected to respective arcuate walls 34d of castellations 34. The ramps 30 are generally wedge-like, with the ramp portions 31 , 32 providing a curved leading face, and a trailing, flat abutment face 37. The capture/retention leg 33 is formed at the free end of the ramp portion 32 (opposite the castellation) and provides a capturing feature to the side of the ramp.

As illustrated in Figure 6 (an assembly cross-section) the capturing feature to the side of the ramp makes sure that there is solid contact between the finger and the ramp.

Behind (i.e. anticlockwise of) each ramp 30 is a projecting detent projection or “bump” 36.

The bump 36 next to the ramp helps hold the fingers 18 in place when they are drivingly engaged with the ramp, and they are also there to help keep the castellation feature orientated. The spring fingers 18 are less likely to be compressed during transit.

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 rotating 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 23 formed in the depending skirt 17 of the outer cap 15. The ribs 21 , 22 extend from the bead 35.

The inner cap 20 is an independent closure in itself for a container. The inner 20 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 20. To assemble the completed closure, the retention bead 23 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 21 allows for the venting of pressure build-up as the inner 20 is assembled into the outer 15 (or vice versa).

Once the retention bead 23 has passed over the retention bead 35, the depending skirt 17 springs back inwardly trapping the inner cap 20 within the outer cap 15. The fit between the outer cap 15 and the inner cap 20 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 20.

In use the inner cap 20 is threadably engaged on an exteriorly threaded finish of a container. A sealing disk (not shown) may be provided in the inner cap 20 and will be trapped between the upper portion of the finish and the lower portion of the top panel of the inner cap 20.

When the outer cap 15 is rotated clockwise spring members 18 are moved so as to become in driving engagement with ramp faces 37. The capture leg prevents the spring finger from escaping (e.g. bending around the ramp, which can damage the fingers) and it catches the spring finger if it slides. This ensures that the force is transferred from the outer to the inner. Thus, the completed closure may be screwed onto the finish of a container (using clockwise rotation in this embodiment), 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 20 as a unit in the tightening (clockwise) 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 20. The outer cap 15 thus can rotate freely with respect to the inner cap 20 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 20.

The spring members 18 serve normally to keep the outer cap 15 and the inner cap 20 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 20. The downward displacement of the outer cap 15 brings the drive dogs 19 into engagement with the spaces between the drive castellations 34. Alignment of the drive dogs 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 dogs 1 properly engaged, the outer cap 15 may be rotated and the inner cap 20 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 re-application. The user may then screw the closure back onto the container finish utilising the driving engagement of the springs 18 and the ratchet faces 37.

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 20. 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 ramps 30 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 20 may be applied by conventional capping machinery, since there is no need for any manipulation of the closure during the tightening procedure.

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