Patent Publication Number: US-9902535-B2

Title: Child-resistant closure

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. National Phase of International Patent Application Serial No. PCT/EP2014/069008, entitled “A CHILD-RESISTANT CLOSURE,” filed on Sep. 5, 2014, which claims priority to Great Britain Patent Application No. 1319118.4 filed on Oct. 30, 2013, the entire contents of each of which are hereby incorporated by reference for all purposes. 
     TECHNICAL FIELD 
     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. 
     BACKGROUND AND SUMMARY 
     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 a first 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. 
     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. 
     According to a second 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 third 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 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: 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
       This application contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. 
         FIG. 1  is a side elevation of a closure formed according to the present invention; 
         FIG. 2  is a plan view of the closure of  FIG. 1 ; 
         FIG. 3  is a perspective view of the top side of an outer cap forming part of the closure of  FIGS. 1 and 2 ; 
         FIG. 4  is a perspective bottom side view of the outer cap of  FIG. 3 ; 
         FIG. 5  is a perspective view of the top side of an inner cap forming part of the closure of  FIGS. 1 and 2 ; 
         FIG. 6  is a perspective bottom side view of the inner cap of  FIG. 5 ; 
         FIG. 7  is a magnified view of the side of the inner cap of  FIGS. 5 and 6  illustrating an assembly rib and drive formation; 
         FIG. 8  is a further magnified view of the rib and drive formation of  FIG. 7 ; 
         FIG. 9  is a magnified plan view of the inner cap illustrating an improved ramp and detent; 
         FIG. 10  is a magnified perspective view of the ramp and detent of  FIG. 9 ; 
         FIG. 11  is a cut-away perspective view illustrating driving engagement of spring fingers on the outer cap with the ramp and detent on the inner cap; 
         FIG. 12  is a cut-away side perspective view illustrating the fingers of  FIG. 11  sliding over the ramp in an unscrewing direction; 
         FIG. 13  is a cut-away rear perspective view of the illustration of  FIG. 12 ; 
         FIG. 14  is a magnified plan view showing the region of a ramp and detent projection of the inner cap; 
         FIG. 15  is a perspective view of the region of  FIG. 15 ; 
         FIG. 16  is an underplan view of an outer cap  115  formed according to an alternative embodiment; 
         FIG. 17  a plan view of an inner cap for use in conjunction with the outer cap of  FIG. 16 ; and 
         FIG. 18  is an underplan view of the inner cap  125  is shown fitted with a disc-shape seal. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIGS. 1 and 2  a closure is shown generally indicated  10 . The closure  10  is made up of two components: an outer cap  15 , shown in  FIGS. 3 and 4  an inner cap  25 , shown in  FIGS. 5 and 6 . 
     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 six spring members  18 , but as few as one or two members may operate satisfactorily, and more than 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 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 five drive lugs  19  is by way of example and a single drive lug would function properly; but multiple drive lugs are preferred to allow a number of different removal engagement positions. 
     On the outer surface of the side skirt  26  a plurality of assembly ribs  20  are provided. The ribs  20  extend axially along the skirt and project outwardly therefrom. There are six ribs  20 , each one being associated with a respective drive lug  19 . 
     In this embodiment the ribs  20  extend along substantially the full height of the skirt  26 . The ribs  20  also extend into and merge with the 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. 
     The ribs  20  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 edge of the drive lug 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. Accordingly the lugs  19  have a very generally shallow U-shape configuration. 
     A retention bead  21  is moulded into the interior wall of the depending skirt  17  near the open end of the depending skirt  17 . The bead  21  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 and 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. 
     The upper portion of the inner cap member  25  is of a general configuration that may be considered to be castellated. A ring wall  33  rises above the plane of the top panel  26 . 
     Spaced at intervals around the ring wall  33  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 . 
     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  21  formed in the depending skirt  17  of the outer cap  15 . 
     Referring also to  FIGS. 14 and 15 , projecting vertically up from and formed integrally with the top panel  26  are a plurality of ratchet lug means. In the embodiment shown the ratchet lug means take the form of six ramp-type lugs  29 . Each of the ramp lugs  29  has a substantially L-shaped configuration formed by an inclined ramp portion  30  joined to a radially extending, axially projecting vertical wall portion  31 . The beginning of the ramp portion is in a plane substantially identical to the plane of the top panel  26 . The vertical wall portion  31  terminates with an abutment face  31   a  and is at an elevation such that the spring members  18  will jam on the face  31   a  if it is attempted to pass them by the vertical wall portion  31 . The wall portion  31  extends radially inwards from the ring wall  33 , approximately from the middle of the drive projection  34 . 
     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. 
     Spaced between each of the ramp lugs  29  are hump-like, arcuately extending detent projections  32 . The detent projections  32  project above the plane of the top panel  26  and lie in the path of travel of the spring members  18  in use. As discussed further below, the projections  32  hold the spring members  18  in place during application of the closure to transmit the force directly to the ramp face  31   a  and help stop the finger deforming back on itself. The profile of the front section  32   a  of the projections is selected to match the corresponding shape of the part of the spring members which lie over them in use (see  FIG. 11 ) so that the support they provide is maximised. The sides  32   b ,  32   c  of the projections are flat and arcuate and generally match the curvature of the sides of the ramp  30 . 
     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  21  is forced over the retention bead  33 , in the process causing the depending skirt  17  of the outer closure cap member  10  to spring outwardly slightly. Once the larger diameter retention bead  21  has passed over the retention bead  33 , 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  31   a  as shown in  FIG. 11 . 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 ratchet lugs  29  and consequently turn the outer cap  15  and the inner cap  25  as a unit in the tightening direction. 
     In the tightening direction, the spring members  18  wedge between the ramps  29  and the projections  32 . 
     Conversely, as illustrated in  FIGS. 12 and 13  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 ratchet lugs  29 . 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. 
     The detent projections  32  act as a further safety feature. If the outer cap  15  is turned in a direction which would normally unscrew the combined closure from the finish, once the springs  18  have risen completely up the ramp portion  30  of the ramp lugs  29  and fallen off the opposite side, the detent projections  32  will tend to hold the springs  18  in that position. It is necessary then to exert further force to move the leaf springs  18  to the next ramp to raise it up the ramp portion  30 . In addition, the detent projections  32  are positioned such that the drive lugs  19  are aligned with the drive projections  34  when the springs  18  are stopped by the detent projections  32 . This position helps prevent overstressing of the springs  18  when the closure is subjected to a vertical load, as in a warehouse. The drive lugs  19  are in contact with the drive projections  34  to prevent this overstressing. 
     In this embodiment the ramps  30  and projections  32  are shaped and profiled so that they support the edge/tip of the spring finger during substantially the entire time it is 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 to normally 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 projections  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 lugs  29 . 
     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. 
     In  FIG. 16  the interior of an outer cap  115  formed according to an alternative embodiment is shown. The cap  115  is very similar to the cap  15 . The curved spring members  118  and the U-shape drive lugs  119  can clearly be seen. 
     In  FIG. 17  a plan view of an inner cap  125  for use in conjunction with the outer cap  115  is shown. 
     In  FIG. 18  an underplan view of the inner cap  125  is shown. The inner cap has been fitted with a disc-shape seal  140  which in this embodiment is attached to the underside of the top panel  126  so that it can seal against the rim of a container neck in use. 
     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.