CN111971234A - Child-resistant closure - Google Patents

Abstract

A childproof lid for a container is provided. The safety cover includes nested outer caps (15) and inner caps (25) respectively having a top panel (16) and side skirts (17) depending generally from the periphery thereof. The outer cap generally loosely surrounds the inner cap to allow relative rotational and axial movement therebetween. The outer cap and the inner cap have respective drive structures that can be brought into driving engagement when the caps are moved axially toward each other to a first axial position. The outer cap includes a plurality of spring members (18) for axially moving the inner and outer caps away from each other to a second axial position. The inner cap includes a top plate provided with a plurality of ramps (30), the spring member providing a biasing force to maintain the outer and inner caps in a second axial position and drivingly engaging the ramps in the second axial position to Drive both the outer and inner caps in the tightening direction, but slide freely over the ramp in the unscrewing direction. Downward pressure on the outer cap is used to move the cap to the first axial position against the bias of the spring fingers to allow unscrewing of the safety cap using the inner and outer cap drive structures. The outer surface of the inner cap side skirt includes a plurality of full height axial ribs (20) for allowing venting when the outer cap and inner cap are initially assembled together. The inner cap drive structure includes a plurality of castellations upstanding from the inner cap top plate, and each full-height axial rib is connected to one of the castellations.

Description

child safety cover

technical field

The present invention generally relates to childproof lids for containers. More particularly, the present invention relates to a child safety cover having an improved apply/release actuation mechanism.

Background technique

Child safety covers are known to include two nested closure members. Typically, the outer cap member and the inner cap member are provided with cooperating sets of lugs that engage each other when the outer closure is rotated in a direction to remove the safety cap from the container. A plurality of spring fingers on the inner surface of the top plate of the outer closure member urges the outer closure member away from the inner closure member and prevents engagement of the lugs. The outer surface of the top plate of the inner closure member is formed with ramps that cooperate with the spring fingers of the outer cap member so that when the outer cap member is rotated relative to the inner cap member in the direction of applying the safety cap to the container, the spring fingers engage the ramps to allow the spring fingers to engage the ramps. The cap members rotate together. When the cap member is rotated in the opposite or unscrewing direction, the spring fingers slide over the ramp to prevent accidental or undesired removal of the closure. Only when the safety cap is rotated in the unscrewing direction and an axial force is simultaneously applied to the outer closure member, the cooperating lugs engage with each other to release the inner closure member from the container.

SUMMARY OF THE INVENTION

The present invention seeks to provide improvements in or related to such safety caps.

According to one aspect of the present invention, there is provided a child safety cover for a container, the safety cover including a nested outer cap and an inner cap having a top panel and side skirts depending generally from the periphery thereof, respectively, the outer cap generally loosely surrounding the inner cap to allow relative rotation and axial movement therebetween, the outer cap and the inner cap having respective drive structures capable of being brought into driving engagement when the caps are moved axially toward each other to the first axial position , the outer cap includes a plurality of spring members for axially moving the inner and outer caps away from each other to a second axial position, the inner cap including a top plate provided with a plurality of ramps, the spring members providing a biasing force to the The outer and inner caps are held in the second axial position and drivingly engage the ramp in the second axial position to simultaneously drive the outer and inner caps in the tightening direction, but slide freely over the ramps in the unscrewing direction, the outer cap Downward pressure on the cap moves the cap to the first axial position against the bias of the spring fingers to allow unscrewing of the safety cap using the inner cap drive structure and the outer cap drive structure, wherein the outer surfaces of the inner cap sides include A plurality of substantially full height axial ribs allowing venting when the outer cap and inner cap are initially assembled together, wherein the inner cap drive structure includes a plurality of castellations upstanding from the inner cap top plate, and wherein each full height axial rib The rib is connected to a battlement.

The safety cover may also include a plurality of non-full-height axial ribs disposed on the inner cap sidewall spaced from the full-height ribs.

The battlements can be roughly U-shaped in plan.

The castellated wall may comprise a first radially extending side wall upstanding from the top plate and a second radially extending side wall upstanding from the top plate, the first and second side walls being located at or towards the periphery of the top plate and spaced from each other , the first side wall and the second side wall are connected by an arc-shaped transverse wall at one end.

A full-height axial rib may extend from the first side wall of the castellated wall.

The first side wall may be connected to each assembly rib by an inclined wall portion.

Castellations can be thinned in non-functional areas.

The full height axial ribs may be spaced from each other around the outer surface of the inner cap side skirt, and the circumferential length of the ribs may be less than the circumferential length of the spaces therebetween.

In some embodiments, a respective detent protrusion is provided for each ramp, which protrudes above the plane of the top plate and in the path traveled by the spring member, which, when drivingly engaged with the ramp, supports the spring member against the Deformation of the spring member by transferring the force to the ramp surface, the profile of the protrusion matches the profile of the area of the spring member with which it comes into contact.

Each ramp may be generally wedge-shaped.

Each ramp may be generally trapezoidal in plan.

In some embodiments, an indentation is provided on the inner cap top plate (substantially) once rotated past each ramp.

Each ramp may be contoured to support the spring member substantially continuously as the spring member passes it in the unscrewing direction.

The profile of each slope can continuously change as the height of the slope increases.

Each ramp may have a variable cross-section sweep, the cross-section of which changes as the height of the ramp increases.

Thus, each ramp can be a feature scanned along a prescribed trajectory.

Each ramp may have a variable cross-sectional sweep with a substantially constant radius trajectory and a changing cross-section along the radial sweep so that the spring member maximally contacts the ramp through rotation.

The ramp may be contoured to support the spring member substantially continuously as the spring member passes it in the unscrewing direction, wherein the ramp has a variable cross-sectional sweep having a generally constant radius trajectory and a changing cross-section along the radius sweep , so that the one or more spring members maximally contact the one or more ramps by rotation.

According to another aspect of the present invention, there is provided a child safety cover for a container, the safety cover including a nested outer cap and an inner cap respectively having a top panel and side skirts depending generally from the periphery thereof, the outer cap The inner cap generally loosely surrounds the inner cap to allow relative rotation and axial movement therebetween, the outer cap and the inner cap having respective drive structures capable of being brought into driving engagement when the caps are moved axially toward each other to the first axial position , one of the inner and outer caps includes one or more spring members for axially moving the inner and outer caps away from each other to a second axial position, and the other of the inner and outer caps includes one or more spring members a ramp, the spring member providing a biasing force to maintain the outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position to simultaneously drive the outer and inner caps in the tightening direction, But sliding freely across the ramp in the unscrewing direction, downward pressure on the outer cap moves the cap to the first axial position against the bias of the spring fingers to allow safe unscrewing using the inner and outer cap drive structures A cover wherein the outer surface of the inner cap side skirt includes one or more axial ribs for allowing venting when the outer cap and inner cap are initially assembled together.

The outer surface of the inner cap side skirts may include a plurality of full height axial ribs for allowing venting when the outer cap and inner cap are initially assembled together, wherein the inner cap drive structure includes a plurality of castellations upstanding from the inner cap top plate , and where each full-height axial rib is connected to a battlement.

In some aspects and embodiments, the assembly ribs are integrally formed with the inner cap drive structure. For example, this can be used to strengthen structures and can allow for lightweight components by removing material.

The rib may be connected to a rim of the drive structure which, in use, is in driving engagement with the drive structure on the outer cap.

The ribs may extend substantially the entire length of the skirt.

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

In some embodiments, the rim of the inner cap is provided with a plurality of castellations.

The or each rib may be attached to the edge of the respective castellation.

The battlements can be roughly U-shaped in plan.

The castellated wall may comprise a first radially extending side wall upstanding from the top plate and a second radially extending side wall upstanding from the top plate, the first and second side walls being located at or towards the periphery of the top plate and spaced from each other , the first side wall and the second side wall are connected by an arc-shaped transverse wall at one end.

In some embodiments, the assembly rib extends from the first side wall of each of the above-described castellations.

The first side wall may be connected to the assembly rib by an inclined wall portion.

Castellations can be thinned in non-functional areas.

The ribs may be spaced apart from each other around the outer surface of the inner cap side skirts, and the circumferential length of the ribs may be less than the circumferential length of the spaces therebetween.

According to another aspect of the present invention, there is provided a child safety cover for a container, the safety cover including a nested outer cap and an inner cap respectively having a top panel and side skirts depending generally from the periphery thereof, the outer cap The inner cap generally loosely surrounds the inner cap to allow relative rotation and axial movement therebetween, the outer cap and the inner cap having respective drive structures capable of being brought into driving engagement when the caps are moved axially toward each other to the first axial position , one of the inner and outer caps includes one or more spring members for axially moving the inner and outer caps away from each other to a second axial position, and the other of the inner and outer caps includes one or more spring members a ramp, the spring member providing a biasing force to maintain the outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position to simultaneously drive the outer and inner caps in the tightening direction, But sliding freely across the ramp in the unscrewing direction, downward pressure on the outer cap moves the cap to the first axial position against the bias of the spring fingers to allow safe unscrewing using the inner and outer cap drive structures A cover wherein for the or each ramp a respective detent protrusion is provided which protrudes above the plane of the top plate and in the path the spring member travels, the protrusion supporting the spring member in driving engagement with the ramp against the Deformation of the spring member caused by transmission to the ramp surface, the profile of the protrusion matches the profile of the area of the spring member with which it comes into contact.

According to another aspect, there is provided a child safety cap for a container, the safety cap comprising a nested outer cap and an inner cap, respectively having a top panel and side skirts depending generally from a periphery thereof, the outer cap being generally loose surrounding the inner cap to allow relative rotation and axial movement therebetween, the outer cap and the inner cap having respective drive structures capable of being brought into driving engagement when the caps are moved axially toward each other to a first axial position, the inner cap and one of the outer caps includes one or more spring members for axially moving the inner and outer caps away from each other to a second axial position, the other of the inner and outer caps includes one or more ramps, The spring member provides a biasing force to maintain the outer and inner caps in the second axial position and drivingly engages the ramp in the second axial position to simultaneously drive the outer and inner caps in the tightening direction, but in the tightening direction Freely sliding across the ramp in the loosening direction, downward pressure on the outer cap moves the cap to a first axial position against the bias of the spring fingers to allow the use of the inner cap drive structure and the outer cap drive structure to unscrew the safety cap, wherein The ramp may be contoured to support the spring member substantially continuously as the spring member passes it in the unscrewing direction.

The profile of the slope can continuously change as the height of the slope increases.

The present invention also provides an inner cap for a child-resistant container lid, this type of safety lid comprising a nested outer cap and inner cap respectively having a top panel and side skirts depending generally from the periphery thereof, the outer cap generally loosely surrounding the inner cap to allow relative rotation and axial movement therebetween, the outer cap and the inner cap having respective drive structures capable of entering driving engagement when the caps are moved axially toward each other to a first axial position, One of the inner and outer caps includes one or more spring members for axially moving the inner and outer caps away from each other to a second axial position, and the other of the inner and outer caps includes one or more spring members a ramp, the spring member providing a biasing force to maintain the outer and inner caps in the second axial position and drivingly engaging the ramps in the second axial position to simultaneously drive the outer and inner caps in the tightening direction, but Freely sliding across the ramp in the unscrewing direction, downward pressure on the outer cap moves the cap to a first axial position against the bias of the spring fingers to allow use of the inner and outer cap drive structures to unscrew the safety cap , wherein the outer surface of the inner cap side skirt includes a plurality of full-height axial ribs for allowing venting when the outer cap and inner cap are initially assembled together, wherein the inner cap drive structure includes a plurality of upstanding from the inner cap top plate A battlement wall, and one of the full-height axial ribs is attached to a battlement wall.

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 lid incorporating a container as described herein.

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

Further particular and preferred aspects of the invention are set out in the appended independent and dependent claims. The dependent claims may suitably combine features of the independent claims and may combine features other than those stated in the claims.

Description of drawings

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

1 is a plan view of the exterior of a safety cover formed in accordance with an embodiment of the present invention;

Figure 2 is a side view of the exterior of the safety cover in Figure 1;

Figure 3 is a perspective view of the outer parts of the safety cover of Figures 1 and 2;

Figure 4 is a bottom perspective view of the security cover exterior components of Figures 1 and 2;

Figures 5 to 9 show top, side, bottom, top and bottom perspective views of the exterior of Figures 1 to 4;

10 is a perspective view of an internal component formed in accordance with an embodiment of the present invention;

Figure 11 is a bottom perspective view of the internal components of Figure 10;

Figures 12-16 show top perspective, top, side, bottom and bottom views of the interior of Figures 10 and 11;

Figures 17 and 18 are enlarged views of a portion of the inner cap showing the assembled ribs and castellations; and

Figures 19 and 20 are enlarged views of a portion of the inner cap showing the ramp.

Detailed ways

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 described herein. Importantly, embodiments can be provided in many alternative ways and should not be construed as limited to the examples set forth herein.

Thus, while embodiments are capable of modification in various ways and take various alternative forms, specific embodiments thereof are illustrated in the accompanying drawings and are described in detail hereinafter by way of example. This is not intended to limit the particular form disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims are to be included. Throughout the drawings and the appropriate detailed description, elements of example embodiments are referred to by the same reference numerals.

The terminology used herein to describe the embodiments is not intended to limit the scope. The articles "a" and "the" are the singular forms having one referent, but the use of the singular form herein should not preclude the presence of a plurality of referents. In other words, there may be one or more of elements referred to in the singular unless the context clearly dictates otherwise. It will be further understood that, when used herein, the term "comprising" recites the presence of stated features, items, steps, operations, elements and/or parts, but does not exclude one or more other features, items, steps , operations, elements, parts, and/or the presence or addition of groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be understood according to the customary practice in the art. It will be further understood that unless expressly defined herein, terms of common usage are also to be understood in accordance with the conventions of the relevant art rather than an idealized or overly formalized meaning.

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

The safety cover of this embodiment consists of two parts: the outer cap 15 shown in Figures 1 to 9 and the inner cap 25 shown in Figures 10 to 20 .

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

A plurality of finger-like spring members 18 are formed on the underside of the top plate 16 and extend to the inside of the outer cap 15 .

The illustrated embodiment shows four curved arcuate spring members 18, but as few as one or two may function satisfactorily, and more than four, such as six, may be employed if desired .

The spring members 18 take the form of angled tabs integrally formed with the underside of the top plate 16 . The spring member 18 is inclined at an angle of approximately 45 degrees relative to the outer member 10; however, the angle of inclination may vary as long as the ratchet function described later is properly performed. Note also that the spring members 18 are positioned radially inwardly of the periphery of the plate 16 . The spring fingers are curved along their length with substantially the same radius of curvature as the side wall 17 .

In addition to the spring members 18, a plurality (eight in this embodiment) of drive lugs 19 are also moulded in the underside of the top plate 16 and hang downwardly. The drive lugs 19 are adjacent the outermost portion of the inner diameter of the outer cap 15 adjacent the depending skirt 17 . The drive lugs 19 then extend inwardly towards the spring 18 , but their edges terminate before reaching the spring member 18 . The drawing of eight drive lugs 19 is by way of example, a single drive lug will also function correctly; however multiple drive lugs may be preferred to allow for multiple different disengagement positions.

A retention bead 21 is molded into the inner wall of the pendant skirt 17 near the opening of the pendant skirt 17 . The ring 21 continues around the entire circumference of the depending skirt 17 .

The outer cap 15 may be fabricated from any material that is sufficiently resilient to provide the necessary spring mass for the integrally molded spring member 18, such as polyethylene or propylene.

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

The inside of the depending skirt 27 is provided with threads 28 for engagement with the threaded neck of the container (not shown).

On the outer surfaces of the sides 27, a plurality of full height assembly ribs 20 are provided. Ribs 20 extend axially along the skirt and project outwardly from the skirt.

In this embodiment, the ribs 20 extend substantially the entire length of the skirt 26 .

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

Ribs 20 and 22 allow for relief of pressure created when the inner and outer caps are assembled together (see below for details). In addition, the ribs provide additional strength to support the rim of the drive lugs (batteries) for engagement when the safety cover is unscrewed. In this embodiment, this additional strength allows the drive lugs to be thinner in non-functional areas.

The general configuration of the upper portion of the inner cap member 25 may be considered castellated. Upwardly or axially extending castellated drive protrusions 34 are spaced apart around the periphery of the top plate. In the assembled safety cover, the drive lugs 19 on the interior of the outer cap 15 are sized so that they can engage in the openings between the drive protrusions 34 . This gives the inner cap member 25 a driving force so that it can be driven by the outer cap 15 .

The top plate 26 is provided with a plurality (eight in this embodiment) of upstanding castellations 34 . Each battlement 34 includes a first radially extending sidewall 34a upstanding from the top plate and a second radially extending sidewall 34b upstanding from the top plate. The first side wall and the second side wall are located at the periphery of the top plate and are spaced apart from each other. The first and second side walls are connected at one end by an arcuate transverse wall 34c.

Assembly ribs 20 extend from each of the first side walls 34a. Assembly ribs 20 are attached to the rim of each of the castellations to provide additional strength to support the rim for engagement when unscrewed. In this embodiment, the first side wall 34a is connected to the assembly rib 20 by an inclined wall segment 34d.

Thus, ribs 20 extend and merge into the inner cap drive lugs, each rib being connected to the leading edge of each castellated drive lug (ie the rim used to provide drive in use).

Weight is removed by thinning the castellations in the non-functional area 60 .

The top plate 26 is also provided with four ramps 30 . The ramps 30 are connected to the arcuate walls 34d of the spaced castellations 34 by extensions 36 . The ramp is generally wedge-shaped, with a curved front guide surface 30a and a rear abutment surface 30b.

Behind each ramp 34 (ie in its counter-clockwise direction) there are shallow grooves 31, depressions, indentations, etc.

The ramps 34 are shaped and contoured so that they support the fingers 18 of the outer cap 15 throughout their contact with these features.

The ramp portion 30 is shaped and contoured such that it follows the same trajectory that the spring fingers follow in use. The section has a variable cross-section sweep, the cross-section of which varies with the height of the ramp, ie the ramp surface is not flat. The trajectory of this portion has a constant radius; the section scanned along the radius (in both the X and Y planes) is constantly changing. This allows the spring fingers to make maximum contact with the ramp by rotation so that at no time there is only point contact between them. This allows the ramp to be formed with the least amount of material while providing maximum contact with the fingers during rotation.

The retaining ring 35 is molded into the outer surface of the depending skirt 27 . The retention ring 35 extends around the entire circumference of the depending skirt 27 and has a diameter larger than the diameter of the retention ring 21 formed in the depending skirt 17 of the outer cap 15 . Ribs 20 and 22 extend from ring 35 .

The inner cap 25 is itself a separate lid for the container. Thus, the inner cap 25 may be made of a suitable material, but not necessarily the same material as the outer cap 15; for example, a thermoplastic material such as polyethylene or polypropylene may be used.

The safety cover 10 is formed by assembling the outer cap 15 and the inner cap 25 . To assemble the complete safety cover, the retaining ring 21 is pressed against the retaining ring 35, causing the depending skirt 17 of the outer cap member 10 to spring outward slightly in the process. The assembly ribs 20 allow for the relief of pressure created when the inner cap 25 is assembled into the outer cap 15 (and vice versa).

Once the larger diameter retaining ring 21 has passed the retaining ring 35 , the depending skirt 17 springs back inward, snapping 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 a significant gap between the inside of the drop skirt 16 and the outside of the drop skirt 32 . Thus, the outer cap 15 can both rotate and slide axially relative to the inner cap 25 .

In use, the inner cap 25 is threadably engageable on the externally threaded neck of the container. A sealing ring (not shown) may be provided in the inner cap 25 and will be caught between the upper part of the neck and the lower part of the top plate of the inner cap 25 .

When the outer cap 15 is rotated clockwise, the spring member 18 moves to come into driving engagement with the faces 30b. Thus, the complete safety cap can be screwed on the neck of the container, as rotation of the outer cap 15 will cause the spring member 18 to drive the engagement ramp 30 and thus the outer cap 15 and the inner cap 25 as a unit in the tightening direction turn.

Conversely, it can be seen that the spring 18 slides over the ramp 30 if the outer cap 15 is rotated in the opposite direction, or in the direction generally unscrewing the cap from the container. The profile of the ramp 30 may continuously change as the ramp height increases. This allows maximum support for the spring fingers 18 .

Thus, these two functions provide a one-way ratchet drive for the inner cap 25 . The outer cap 15 is thus free to rotate relative to the inner cap 25 in the unscrewing direction. This feature makes the cover child-resistant since it cannot unscrew the combined cover without additional action.

In this embodiment, the ramps 30 are shaped and contoured such that they support the edges/tips of the spring fingers 18 throughout their contact with these features.

In order to remove the cap from the container neck, the outer cap 15 must be pressed down on the inner cap 25 .

The spring member 18 normally serves to hold the outer cap 15 and the inner cap 25 in their axially spaced relationship in which it is not possible to remove the cap from the container. However, the outer cap 15 can be pressed down on the inner cap 25 using the elastic function of the spring 18 . The downward displacement of the outer cap 15 engages the space between the drive lugs 19 and the drive battlements 34 .

When the outer cap 15 is pressed down, the alignment of the spacing between the lugs 19 and the drive protrusions 34 may not be complete. However, a slight rotation of the outer cap 15 in the release direction will bring these components into proper driving engagement. With proper engagement with the drive lugs 19, the outer cap 15 can rotate and the inner cap 25 rotates with it as a unit through this drive engagement.

Once the combined lid is removed from the container and the downward pressure on the outer cap 15 is released, the combined lid will spring back under the influence of the spring member 18, placing the lid in a configuration suitable for reapplication. The user can then screw the cap back onto the container neck using the actuated combination of spring 18 and ratchet surface 30b.

Once back on the container, the combined lid cannot be removed again without pressing the outer cap 15 down on the inner cap 25. When a child attempts to remove the assembled cap from the container without pressing down on the inner cap 15, an alarm sounds. The spring 18 slides over the ratchet lugs 29 and hits the top plate 26 producing a loud and distinctive "click" sound. The sound can be heard at a distance and can serve as a warning to parents that children are messing with containers whose contents are harmful to them.

The safety cap of the present invention assembled from the outer cap 15 and the inner cap 25 can be applied by conventional capping machinery as no manipulation of the cap is required during the fastening procedure.

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

Claims (17)

1. A child safety lid for a container comprising nested outer and inner caps respectively having a top panel and side skirts depending generally from the periphery thereof, the outer cap generally loosely surrounding the an inner cap to allow relative rotation and axial movement therebetween, the outer cap and the inner cap having respective drives capable of being brought into driving engagement when the caps are moved axially toward each other to a first axial position structure, the outer cap includes a plurality of spring members for axially moving the inner cap and the outer cap away from each other to a second axial position, the inner cap includes a top plate provided with a plurality of slopes, so The spring member provides a biasing force to maintain the outer cap and the inner cap in the second axial position and drivingly engages the ramp in the second axial position for simultaneous driving in the tightening direction The outer cap and the inner cap, but slide freely across the ramp in the unscrewing direction, the downward pressure on the outer cap moves the cap to the first axial direction against the bias of the spring fingers position to allow use of the inner cap drive structure and the outer cap drive structure to unscrew the safety cover, wherein the outer surface of the inner cap side skirt includes a a plurality of substantially full height axial ribs allowing venting when initially assembled together, wherein the inner cap drive structure includes a plurality of castellations upstanding from the inner cap top plate, and wherein each full height axial rib Attached to a battlement. 2. The safety cover of claim 1, further comprising a plurality of non-full-height axial ribs disposed on the inner cap sidewall spaced from the full-height ribs. 3. A safety cover as claimed in claim 1 or 2, wherein the battlements are generally U-shaped in plan. 4. The safety cover of claim 3, wherein the castellated wall includes a first radially extending sidewall upstanding from the top panel and a second radially extending sidewall upstanding from the top panel, the first radially extending sidewall upstanding from the top panel. The side wall and the second side wall are located at or towards the periphery of the top panel and are spaced apart from each other, the first side wall and the second side wall being connected at one end by an arcuate transverse wall. 5. The safety cover of claim 4, wherein the full height axial rib extends from the first side wall. 6. The safety cover of claim 5, wherein the first side wall is connected to the assembly rib by an inclined wall portion. 7. The safety cover of any preceding claim, wherein the castellations are thinned in non-functional areas. 8. A safety cover as claimed in any preceding claim, wherein the full height axial ribs are spaced from each other around the outer surface of the inner cap side skirt, and the circumferential length of the ribs may be less than The circumferential length of the interval between. 9. A safety cover as claimed in any preceding claim, wherein for each ramp there is provided a respective detent projection projecting above the plane of the top plate and in the path travelled by the spring member, the The protrusion, in driving engagement with the ramp, supports the spring member against deformation of the spring member due to its transfer of force to the ramp face, the protrusion is contoured to the area of the spring member that contacts it Contour matching. 10. A safety cover as claimed in any preceding claim, wherein each ramp is generally wedge-shaped. 11. A safety cover as claimed in any preceding claim, wherein each ramp is generally trapezoidal in plan. 12. A safety cover as claimed in any preceding claim, wherein an indentation is provided on the inner cap top plate upon rotation beyond each ramp. 13. A safety cover as claimed in any preceding claim, wherein each ramp is contoured to support the spring member substantially continuously as the spring member passes it in the unscrewing direction. 14. A safety cover as claimed in any preceding claim, wherein the profile of each ramp is continuously variable as the ramp height increases. 15. A safety cover as claimed in any preceding claim, wherein each ramp has a variable cross-section sweep having a substantially constant radius trajectory and a changing cross-section along the radius sweep such that the spring member Maximize contact with the ramp by rotating. 16. A safety cover as claimed in any preceding claim, wherein the ramp may be contoured to support the spring member substantially continuously as the spring member passes it in the unscrewing direction, wherein the ramp Having a variable cross-section scan with a substantially constant radius trajectory and a continuously changing cross-section along the radius scan such that the one or more spring members maximally contact the one or more ramps by rotation. 17. A safety cap as claimed in any preceding claim in combination with a container.

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