Abstract:
A bi-modal closure for a container opening is provided. The closure has a first mode intended for adult use, wherein the closure is readily opened, and a second child-resistant mode, wherein the closure is more difficult to open, especially by children. The conversion between modes is accomplished by use of a bi-stable element located in the closure.

Description:
FIELD OF THE INVENTION 
     The present invention relates to closure members for containers, bottles, and the like, and more particularly, to child-resistant push-and-turn closure members which are adapted for use on dispensing containers for potentially hazardous materials, such as pharmaceutical agents. 
     SUMMARY OF THE INVENTION 
     The present invention provides for the bi-modal operation of a closure for a container opening. The closure has a first mode intended for adult use, wherein the closure is readily opened, and a second child-resistant mode, wherein the closure is more difficult to open, especially by children. When engaged to an opening, at least a portion of the closure (a deflecting member) has a distal relationship to the opening wherein the closure is substantially non-removable from the opening, and a proximal relationship to the opening wherein the closure may be easily removed from the opening. In the first mode, the movement between the distal and the proximal relationships requires little or no downward force; while in the second mode, the force require to effect the movement is greatly increased (when the force required to move between the distal and proximal relationships in the first mode is non-zero, the force required in the second mode should be at least 25% greater than that required in the first mode, preferably 50% greater, and most preferably at least twice that of the first mode). The conversion between modes is accomplished by use of a bi-stable spring located in the closure, preferably on the top surface of the closure. The bi-stable spring is preferably an invertible disk, and in the first mode presents a convex surface to the user. Depressing this surface with sufficient force results in the inversion of the disk into a stable second mode wherein the disk is concave, and wherein the disk serves to directly or indirectly urge the closure (or part of the closure) into the distal relationship with the opening. The geometrical state of the disk serves as a visual and tactile cue as to the instant mode of the closure. Conversion may typically be accomplished with finger pressure alone, and without the need to disengage the closure from the bottle. The details of the internal structure of the closure may be altered to allow finger pressure to return the closure to the first mode (by accessing the back side of the closure), or the conversion to the second mode from the first mode may be made irreversible by preventing access to the bi-stable spring element from the back side of the closure. 
     It is an object of the present invention, therefore, to provide a container closure convertible from a first adult-use mode to a second child-resistant mode. 
     The closure has a bi-stable element in its upper surface with a first substantially convex stable orientation and a second substantially concave stable orientation. The first stable orientation has a first associated spring rate of the deflecting member, and the second stable orientation has a second associated spring rate of the deflecting member, wherein the second spring rate is greater than the first spring rate, and wherein the bi-stable element may be converted from the first to the second stable orientations by finger pressure. 
     A further object of the invention is to provide an intuitively natural means for converting the container closure from the first mode to the second mode. 
     Yet another object of one embodiment of the invention is to provide a reversibly convertible container closure, wherein the closure may be converted from an adult-use mode to a child-resistant mode and back again. 
     Yet another object of one embodiment of the invention is to provide an irreversibly convertible container closure. 
     Yet another object of one embodiment of the invention is to provide a bi-modal container closure that can be converted from an adult use mode to a child-resistant mode while closed. 
     Yet another object of one embodiment of the invention is to provide a container system selectable between adult and child-resistant modes, for storage of potentially hazardous materials, especially pharmaceutical agents. 
     And yet another object of the invention is to provide a convertible container closure having a tactile and/or visual indication of operational status. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above as well as other objects of the invention will become more apparent from the following detailed description of the preferred embodiments of the invention, when taken together with the accompanying drawings in which: 
     FIG. 1A is a cross-sectional view of a push-and-turn closure according to one embodiment of the invention, wherein the closure is in the first (adult-use) mode. 
     FIG. 1B is a cross-sectional view of a push-and-turn closure according to one embodiment of the invention, wherein the closure is in the second (child-resistant) mode. 
     FIG. 2 is a cross-sectional view of the push-and-turn closure as shown in FIG. 1B, with the closure engaged to the opening of a container. 
     FIG. 3 is a partial cross-sectional view of the push-and-turn closure as shown in FIG. 2, showing one of a plurality of bayonet teeth. 
     FIG. 4 is a view of the push-and-turn closure as shown in FIG. 3, in the direction indicated by arrow  3 . 
     FIG. 5 is a cross-sectional view of a push-and-turn closure according to one embodiment of the invention, wherein the closure is in the first (adult) mode. 
     FIG. 6A is a cross-sectional view of a push-and-turn closure according to one embodiment of the invention, showing an alternative unitary construction of the bi-stable disk. 
     FIG. 6B is a cross-sectional view of a push-and-turn closure of FIG. 6A, shown in the second mode. 
     FIG. 7 is a cross-sectional view of a push-and-turn closure according to one embodiment of the invention, showing an alternative placement of the bi-stable disk. 
     FIG. 8A is a partial cross-sectional view of a push-and-turn closure engaged to a container, according to one embodiment of the invention, with the closure in the first mode. 
     FIG. 8B is a partial cross-sectional view of a push-and-turn closure engaged to a container, as shown in FIG. 8A, with the closure in the second mode. 
     FIG. 9A is a cross-sectional view of a push-and-turn closure, according to one embodiment of the invention, with the closure in the first mode. 
     FIG. 9B is a cross-sectional view of a push-and-turn closure, according to one embodiment of the invention, with the closure in the second mode. 
     FIG. 10 is a cross-sectional view of a push-and-turn closure of FIG. 9B engaged to a container. 
     FIG. 11A is a cross-sectional view of a push-and-turn closure, according to one embodiment of the invention, with the closure in the first mode. 
     FIG. 11B is a cross-sectional view of a push-and-turn closure, according to one embodiment of the invention, with the closure in the second mode. 
     FIG. 12A is a cross-sectional view of a push-and-turn closure engaged to a container, according to one embodiment of the invention, with the closure in the first mode. 
     FIG. 12B is a perspective view of a push-and-turn closure engaged to a container of FIG.  12 A. 
     FIG. 13A is a cross-sectional view of a push-and-turn closure, according to one embodiment of the invention, with the closure in the first mode. 
     FIG. 13B is a cross-sectional view of a push-and-turn closure, according to one embodiment of the invention, with the closure in the second mode. 
     FIG. 14 is a top view of a push-and-turn closure in the first mode, according to one embodiment of the invention, with a spoked bi-stable element. 
     FIG. 15 is a cross-sectional view of a push-and-turn closure in the first mode, according to one embodiment of the invention, with a spoked bi-stable element. 
    
    
     DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1A and 1B, in accordance with one embodiment of the invention, the convertible closure, generally indicated by numeral  1 , comprises lower ring  4  carrying projecting internal tabs  18 . The lower ring  4  is continuous with the upper ring  14 , which supports the curved disk  12  by pressure or adhesive contact with the annular disk ring  20 . The closure may comprise any polymeric or elastomeric material used to manufacture closures, and the curved disk  12  may even comprise a metallic material, with adjustments made to the thickness of the disk to compensate for the varying differences in modulus of these materials. The closure taper  6  having taper face  8 , is supported by top  10 , which is integral with the lower ring  4 . The combination of closure taper  6  and top  10  is somewhat compliant, and deflects vertically along the vertical axis of the closure relative to the upper ring  14  and the rest of the closure  1 , when downward vertical force is applied to the upper ring  14 . In FIG. 1A, the closure  1  is in the first (adult-use) mode, while in FIG. 1B, the closure is in the second (child-resistant) mode. In the second mode, the bi-stable curved disk  12  is inverted into the second stable position, and loads the top  10  by pressure contact, thereby increasing the effective spring rate of the top  10  and increasing its resistance to vertical deflection when downward pressure is applied to upper ring  14 . It is preferred that the effective spring rate in the second mode be at least one pound per inch, and more preferably at least five pounds per inch. 
     Referring now to FIG. 2, the closure  1  is shown in second mode engagement with container  2 , comprising tube  28 , base  30 , closure taper  6 , and bayonet teeth  24 . Container taper  26  makes contact with closure taper  6  to seal the interior of the container  2 . Bayonet teeth  24  integral with the container  2  engage with tabs  18  of the closure  1 , so that pressure must be applied to the closure  1  in direction  3 , followed by a twisting action in direction  5 , in order to decouple the bayonet teeth  24  from the integral tabs  18  of the closure  1 . Pressure in the direction  3  is resisted in part by the curved disk  12  in pressure contact with the top  10 . 
     In FIG. 3, the closure  1  in second mode engagement with container  2  is shown in a partial cut-away view to show detail of the bayonet tooth  24 . The tooth  24  comprises ramp  34  and land  36 . The upper surface of tab  18  of the closure  1  rests against land  36 , and cannot escape unless pressure is applied to the closure in direction  3 , while the closure is twisted in direction  5  relative to container  2 . The geometry of the tooth  24  is a non-exclusive example of engagement means that may be used with the instant invention, and any tooth geometry or other means that allows the closure to decouple from the container by pressing and then turning of the closure relative to the container may be used. 
     In FIG. 4, the closure of FIG. 3 is shown in direction  3 . The central area of contact of the curved disk  12  with the underlying top is shown as the area  40 . If the curved disk  12  is translucent, area  40  on the top  10  (FIG. 3) will be revealed by contact pressure, and will be hidden when the curved disk  12  is curved upwards so that it is not in contact with the top. The area  40  may be used to further indicate that the closure is in the second (child-resistant) mode. In FIG. 4, area  40  is in the form a solid color. Symbols such as a lock icon, or text such as “PRESS AND TURN”, may be substituted for the solid color shown, as desired. 
     Turning now to FIG. 5, a closure according to an alternative embodiment of the instant invention is generally indicated by numeral  100 . The bi-stable curved disk  50  is integral with the upper ring  54 , while the closure taper  52  is part of the separate taper insert, indicated generally by numeral  56 . The taper insert  56  is somewhat compliant, and deflects vertically along the vertical axis of the clsoure relative to the upper ring  54  and the rest of the closure  100 , when downward vertical force is applied to the upper ring  54 . The taper insert  56  also comprises top  44 , and reversible section  46  with tab  48 , by which the user may return the closure  100  from the first mode to the second mode by applying finger pressure to the lower surface of the reversible section  46 . 
     In FIG. 6A, an alternative embodiment of a one-piece closure generally indicated by numeral  101  is shown in the first mode. Curved disk  60  is integral with closure taper  62 . The position of the curved disk  60  near the tip of the closure taper  62  tends to resist inward deformation of the taper when engaged to a container. In FIG. 6B, the curved disk  60  is shown inverted. If the curved disk  60  is molded in the first mode, it will tend to invert to a shallower curvature in the second mode, and therefore will tend to spread out the closure taper  62 , effectively resulting in a greater spring rate of the taper, and will therefore require more downward pressure to achieve the proximal orientation with an engaged opening in the second mode as compared to the first mode. 
     In FIG. 7, another alternative placement of the curved disk  60  is shown in the closure generally indicated by numeral  102 . In this embodiment, reversal of the curved disk tends to spread the conic ring  64  which supports closure taper  62 , thereby tending to move the closure taper towards the lower part of the closure  102 , and increasing the effective spring rate when engaged with a container. 
     Turning now to FIG. 8A, a reversible closure according to an alternative embodiment of the instant invention is generally indicated by numeral  103 , which is shown in first mode engagement with container  200 . Container  200  is shown in partial section to illustrate the deformation of compliant seal  66 , which is shown on the left side to deform against the upper edge of container  200  to effect a seal in the first mode. In FIG. 8B, the closure  103  is shown in the second mode, with the compliant seal  66  under greater deformation, thereby increasing the force necessary to decouple the closure from the container. The compliant seal  66  may be formed of soft rubber, with foam rubber preferred. It is most preferred that the outside surface of the compliant seal have a continuous skin, so as to best exclude water vapor and oxygen from the interior of the container  200 . 
     FIGS. 9A and 9B illustrate an alternative embodiment of the instant invention, wherein the reversible closure is generally indicated by the numeral  104 . In FIG. 9A, the closure is shown in the first mode, with bi-stable disk  76  curved upwards. At stress relief  78 , disk  76  is joined to top  74 , and thence to top  74 , which is in turn supported by ring  72 . Top  74  also serves as support for closure taper  70 . Projecting from the lower surface of disk  76  are a plurality of fingers  68 . In FIG. 9B, the closure  104  is shown in a disengaged second mode, wherein the disk  76  is inverted, allowing fingers  68  to contact the inner surface of closure taper  70 , thereby stiffening the taper and increasing the force needed to remove the closure from the container  202  (as shown engaged in FIG.  10 ). 
     In the embodiments described in FIGS. 1-10, the closures have all been of the partial turn type, that is, a twist of less than 360 degrees divided by the number of teeth is required to effect full closure (or opening). In FIGS. 11-12, another embodiment is shown wherein more than one half turn is typically required (depending upon the pitch of the teeth). In FIGS. 11A and 11B, closure  105  in shown in the first mode, wherein the drive ring  82  is in a distal orientation relative to the rest of the closure. The cap  86  has threads  88  for engaging a container. In the first mode, flaps  98  serve to space the drive ring  82  from the cap  86 , thereby separating the drive teeth  92 , attached to the lower surface of the drive ring, from the driven teeth  94 , attached to the upper surface of the cap  86 . The flaps  98  are optional, and are intended only to supply a sufficient force to keep the cap  86  in a distal orientation to the opening of an engaged container. 
     In FIG. 11B, the closure  105  is shown in the second mode, with the disk  80  in the inverted position. In this inverted position, the disk  80  acts as a spring to keep the drive ring  82  in the distal position, and thereby keeps the closure  105  in the second (child-resistant) mode, while projection  84  serves to prevent the drive ring  82  from being removed from the cap  86 . 
     Turning now to FIG. 12A, the closure  105  is shown in the first (adult-use) mode, engaged to container  203 . A slight pressure is applied to the upper surface of closure  105  to place the ring  105  in the proximal position, so that drive teeth  92  engage with driven teeth  94 , whereby the cap may be twisted from the container  203 . In FIG. 12B, the closure  105  is shown engaged with container  203  in a perspective view. Since the disk is convex, the user is informed that closure is in the adult-use mode. 
     In FIG. 13A, the closure  108  is shown in the first mode. Compliant element  113 , preferably comprising an elastomeric or rubber foam, is situated between the disk  80  and the cup  96 , where the element  113 , if already slightly compressed, serves to supply sufficient force to keep the drive ring  82  in the distal position. In FIG. 13B, the closure  108  is shown in the second mode. Compliant element  113  is compressed between the disk  80  and the cup  96 , where the element  113  serves to increase the spring rate to place the closure  108  in the second mode. 
     In the embodiments described in FIGS. 1-13, the closures have all embodied bi-stable disks. In FIGS. 14 and 15, a closure  106  is shown which employs a bi-stable spoked element  111  with three straight spokes  110  (although any plurality of spokes may be employed). The spokes  110  are supported by a triangular center  112 , and an annular ring  114 , which fits into the upper ring  14  of closure  106 . Reversal of the spoked element (not shown) adds to the spring constant of the top  10  in the same way as the bi-stable disk previously described. 
     Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.