This invention was made with the United States (U.S.) Government support under Grant No. 5 R44 HD24009-03 awarded by the National Institute of Child Health and Human Development. The U.S. Government has certain rights in the invention.

TECHNICAL FIELD The present invention relates to structures capable of rendering closures child resistant and tamper evident while maintaining ease of adult use. In particular, the present invention relates to structures that make combination lock closures sufficiently child resistant to provide adequate protection of child health yet not so complex as to be uneconomical or excessively inconvenient for adults. The term "closure" is used herein in accordance with its dictionary definition of "something that closes." Similarly, the term "close" is also used in accordance with its dictionary definition of "to put (something) in a position to obstruct an entrance, opening, etc." or "to stop or obstruct (a gap, entrance, aperture, etc.)" or "to block or hinder passage across; prevent access to." The best mode of the invention involves closures on child-resistant packaging but the invention is applicable to any child-resistant feature that prevents access to something that is capable of being enclosed.

BACKGROUND ART

A child-resistant closure is essentially a locked closure having a "key" that adults possess and children do not. Most child-resistant packaging (CRP) on the market today relies on "locking" closures that have both cognitive skill and strength or dexterity based "keys". Generally, older adults find this type

of CRP to be difficult to use. Other types of CRP utilize actual keys, but are less practical.

CRP with locking closure mechanisms that do not rely on actual keys or on presumed strength or dexterity differences between children and adults are also possible. These types of child-resistant closures are cognitive skill based, that is, they rely on cognitive skills that adults possess and children under the age of five do not, e.g., problem-solving skills. Cognitive skill based CRP closures proposed to date rely on combination lock mechanisms, maze (or labyrinth) closures, dual (or reverse) thread closures or a combination of these technologies. The present invention relates to combination lock mechanisms. Combination lock closure mechanisms appropriate for providing child resistance for packages are of two basic types. With one type, the mechanical elements that maintain the locked condition are directly manipulated (actually touched) by the user. The puzzle-lock (also known as the letter-lock or ring- lock) is the classic example of this type.

With the second basic type of combination lock, at least some of the mechanical elements that maintain the locked condition are manipulated indirectly. With this type of lock, only one locking element need be directly moved and it, in turn, moves (usually rotates) either one (directly) or all (some indirectly) of the other locking elements (usually tumblers) . Child-resistant packaging designs having combination lock closures of the first type have been disclosed by a number of inventors. U.S. Patents disclosing such inventions include those issued to Baum (446,657), Cowles (841,668), Sauber (3,033,406), Kimball (3,129,834), St. Pierre (3,405,828), Millis

(3,407,954), Sotory (3,421,347), Johnson (3,445,021), Drew et al. (3,669,296), Leopoldi et al. (3,684,117),

Meyer (3,843,007) and Meyer (3,850,324). These closure designs have not achieved commercial success because they are too complex. They generally comprise multiple movable parts and, as a consequence, have a 5 higher manufacturing cost and present a higher level of complexity to the user.

Under current and proposed regulations of the U.S. Consumer Product Safety Commission (CPSC), child- resistance effectiveness (CRE) and older adult use

10 effectiveness (OAUE) of CRP closure designs are measured using standard test protocols. CRE is measured by asking pairs of children in a specified age group (generally under five years of age) to attempt to open the package closure in specified time

15 periods both before and after a nonverbal demonstration. The CRE is the fraction (proportion) of children in the group (expressed as a percentage) that is unable to open the package. OAUE is measured by asking individual adults in a specified age group

20 (typically 60 - 75 years) to open and close the package using the instructions supplied with it within a specified time period. The OAUE is the fraction (proportion) of adults in the group (expressed as a percentage) that is able to open and close the

25 package.

Five prior art patents by the present inventor, U.S. Patents 4,782,963, 4,991,729, 5,017,128, 5,085,578, and 5,184,376, the contents of which are incorporated herein as if actually set forth,

30 illustrate combination lock mechanisms and structures that could be dimensioned as disclosed herein to provide an appropriate CRE (child resistance _% effectiveness) and OAUE (older adult use effectiveness) . These patents do not, however, teach ₄ . 35 how to dimension and configure the combination lock mechanisms and structures in the manner disclosed herein.

DISCLOSURE OF THE INVENTION The present invention provides structures capable of rendering closures child resistant and tamper evident while maintaining ease of adult use and low cost of manufacture. The technique can be applied to closures whose use requires adults to perform a simple combination of moves to either remove the closure or otherwise gain access to container contents or operate an operating mechanism. Such closure designs rely for their effectiveness on cognitive skill differences between young children and adults. They pose a problem that adults can solve and that young children cannot. Closure designs can be optimized by reducing closure complexity (and, therefore, cost) to the minimum level required to meet government regulations for child resistance or market demands. Furthermore, closure designs can be optimized by providing a level of complexity that does not reduce elder accessibility below acceptable levels.

In its broadest sense, the invention is a structure capable of rendering child resistant an enclosure having a combination lock closure mechanism. The closure mechanism comprises fastening means on a container part and fastening means on a closure part and one or more tumblers movably attached to one of the two parts. Structures which could be configured and dimensioned in the manner disclosed herein are disclosed in U.S. Patent Application Serial Nos. 07/437,656, 07/592,577 and 07/828,716, the contents of which are incorporated herein as if actually set forth.

More specifically the present invention concerns a generally cylindrical relatively rotatable lock structure comprising coaxial and relatively rotatable first, second and third members. The first and second members have opposed surfaces carrying connecting

means which interengage to prevent relative axial movement between those members, except in predetermined relative rotatable positions. The third member is supported to prevent axial movement relative \ 5 to the supporting member but to permit rotatable movement subject to friction between the third and non-supporting members. Friction causes the third member to rotate with the non-supporting member. The third member has on its face opposite the non- 10 supporting member connecting means cooperable with the connecting means on the opposed face of the non- supporting member to prevent relative axial movement between the third and non-supporting member except in predetermined relative rotatable positions. Opposing 15 stop members are provided on the third member and the supporting member limiting their relative rotation in one direction to less than one revolution before stop faces on the stop members abut, after which the third member is driven by the stop members to rotate with 20 the supporting member. At least one of the stop members has a ramp on the face opposed to the stop face, which ramp is of such pitch that the other stop member, upon encountering the ramp, is able to ride up the ramp and over the stop member whenever relative 25 rotation is in the direction opposite to that causing contact between the stop faces.

BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a side elevational view of a container 30 and a closure cap supporting a relatively rotatable member with the closure cap removed and spaced from the container;

Fig. la is an elevational view of only the top part of an alternative embodiment of the container .. 35 only from the opposite side;

Fig. 2 is a top plan view of the container of Fig. 1;

Fig. 3 is a sectional view taken along line 3-3 of Fig. 2 with the closure cap of Fig. 1 also shown in section and also with a shrink-wrap protective cover in place over the combination lock portions of the container and closure;

Fig. 4 is a plan view of the closure cap of Fig. 1 from below;

Fig. 5 is a sectional view taken along line 5-5 of Fig. 4; Fig. 6 is a plan view of the top of the relatively movable member of Fig. 1;

Fig. 7 is a sectional view taken along line 7-7 of Fig. 6;

Fig. 8 is a plan view from above of the closure cap assembled on the container;

Fig. 9 is plan view from above of the closure cap having different markings on the container;

Fig. 10 is a third plan view of the closure cap having different markings on the container;

BEST MODE FOR CARRYING OUT THE INVENTION Referring to Figs. 1, la, 2, and 3, there is illustrated a container, generally designated 10, for example, a pill bottle. The body portion of the container may be blow molded, injection molded, machined or otherwise conventionally fabricated of moldable resinous material. Alternatively, it may be molded from glass or machined or otherwise fabricated of another material. Container 10 may be of any shape and dimensions provided it is terminated in a neck 14 of cylindrical form, through which is provided an open mouth access to the interior of body 12 of the container 10. The term "neck" should not be construed to mean a narrowed portion, although in many structures that will be the form it takes. On the outer cylindrical surface of neck 14 are molded or otherwise provided fastening means in the form of

circumferential ribs 16 and 18. The bottom surface of each of the ribs 16 and 18 is generally flat and is preferably within 10 degrees of being perpendicular to the cylindrical surface of neck 14. Each of the ribs 16 and 18 is provided with a discontinuity or channel

21 and 22 of sufficient width to permit passage of a stud, a cooperating fastening means as described below. Although they may vary in specific geometry and dimensions, as well as cross-sectional shape, a preferred cross-section shape for the ribs is generally triangular or trapezoidal, perhaps beveled with two slopes 16a, 16b and 18a, 18b as seen in Fig. 1. The ribs increase in axial thickness and in diameter in the direction away from the mouth as shown in Figs. 1 and 3. In preferred embodiments, a shape providing a ramp 16a, 16b or 18a, 18b or inclined plane permits the studs of the cap to be snapped over the ribs as the closure cap is placed onto the container. Stepped stop collar 13 located at the lower end of neck 14 provides a stop shoulder generally perpendicular to the cylindrical neck which limits axial movement of the closure studs as seen in Fig. 3 and prevents children from gaining purchase on the lower edge of sidewalls 23 of closure cap 20. Sidewalls 23 of closure cap 20 snugly receive the smaller diameter of the stepped outer cylindrical surface 15 of stepped collar 13 when closure cap 20 is placed on the container as seen in Fig. 3. The presence of stepped cylindrical surface 15 prevents closure cap 20 from being squeezed into an oval shape during attempts by children to rip it off the container when it is in the locked condition. Stop collar 13, located below cylindrical surface 15, extends radially outward to limit movement of and access to the bottom edge or lip of closure cap 20 when closure cap 20 is placed on the container.

Considering now the closure cap 20 of Figs. 1, 4

and 5, the structure includes generally cylindrical sidewalls 23 and closing end wall or top 24 transverse to the sidewalls. Closure cap may be injection molded or machined or otherwise fabricated. Sidewalls 23 provide a generally cylindrical internal surface whose diameter is considerably larger than the neck 14 of the container and at least at the lip conforms to the outer cylindrical surface 15.

Generally cylindrical rotatable member 30 is illustrated on Figs. 1, 3, 6 and 7. Rotatable member

30 fits within closure cap 20 as best seen in Fig. 3 and is supported in position by circumferential retainer ring 40 so as to be rotatable relative to cap 20. Generally cylindrical rotatable member 30 may be injection molded or machined or otherwise fabricated.

Generally cylindrical rotatable member 30 need not be of the cap configuration shown. It may be of tubular shape for example. Rotatable member 30 as seen in Fig. 6 carries a stop 31 on its outer surface. During rotation stop 31 interacts with interfering stop 26 on closure cap 20 as seen in Figs. 4 and 5. Stop 26 extends downward from the top 24 of closure cap 20 and, in preferred embodiments, is radially spaced inward from sidewalls 23. Stop 31 extends up from the top 34 of rotatable member 30 offset from the edge at the same general radius at stop 26 so as to make contact with stop 26. As seen in Fig. 5, two inwardly projecting studs 38 and 39 are provided on the inner cylindrical surface of sidewall 23 of closure cap 20. Similarly two inwardly projecting studs 36 and 37 are provided on inner wall 33 of rotatable member 30. The studs 36 and 38 are of a width to pass through channels 22 and 21, respectively, and are so positioned on closure walls 23 and rotatable member walls 33 as to lie below ribs 18 and 16 when the lip of the sidewalls 23 contacts abutment 13 as the cap is placed over the neck of the container. Studs 37 and

39 preferably are wider circumferentially than studs 36 and 38 and are of a width that cannot pass through channels 22 and 21, respectively. In an alternative embodiment (shown in Fig. la) having similar channels

<• 5 21a and 22a on the opposite side of neck 14, studs 37 and 39 preferably are wider circumferentially than » studs 36 and 38 and are of a width that cannot pass through channels 22a and 21a. In this embodiment, studs 36 and 38 are of a width to pass through 10 channels 22a and 21a, respectively. Studs 36 and 37 are so positioned on wall 33 as to lie below rib 18 and studs 38 and 39 are so positioned on wall 23 as to lie below the rib 16 when the closure 20 is in place against stop 13. Although they may vary in specific 15 geometry and axial length, as well as cross-sectional shape, at least a portion of the top surfaces of studs 36 and 38 are generally flat. In the best mode, the studs form and dimensions permit the studs to be snapped over the ribs as the closure cap is placed 20 onto the container. The essentially flat portion of the top of studs 36 and 38 is generally parallel to the generally flat lower surface of ribs 16 and 18 when the closure cap is placed onto the container. The studs 36 and 38 and ribs 16 and 18 thus comprise a 25 locking snap fastening means.

In practice, the rotatable member 30 is loosely held in the closure cap 20 by the small retainer ring

40 past which the rotatable member is forced in assembly. The loose fit is designed into the

30 structure just as a snug fit is designed between the closure cap and the container. In the best mode, a snug fit is provided by inserting a compressible, i disk-shaped liner 41 in the top of rotatable member 30 so that it is compressed between the member and the 35 top edge of the container neck 14 when rotatable member 30 is snapped on container 10 (Fig. 3) . Sidewalls 33 are designed to deform in shape and/or

circumferential length to provide a snap fit. Other methods of accomplishing such a frictional engagement are disclosed in the inventor's U.S. Patent Nos. 4,782,963 and 4,991,729. Use of a compressible liner 41 has the effect of tightly closing the container to prevent moisture permeation into the package as well as causing the relatively rotatable member 30 not to rotate with the closure cap but to stay with the body 12 of container 10 during relative rotation until the stops 26 and 31 make contact. At that point, closure cap 20 will drive and rotate rotatable member 30 by means of the stops and against the frictional force.

Assuming that the closure cap is on the container and one wishes to remove it, it is convenient to provide markings on the container and closure cap to enable realignment of the studs and channels. In the embodiment shown on Fig. 2, markings 50 and 51 are printed on tabs 52 and 53 in contrasting color using a relatively large typeface such as Helvetica 12 point. They are shown as the black numerals 1 and 2 on tabs 52 and 53 on container 10 on Fig. 2. An embossed black line 55 on the closure 20 acts as a pointer to the markings 50 and 51. Alternatively, the radially directed arrows 57, 58 and 59 on the closure caps 20 seen in Figs. 8, 9 and 10 may be used as the pointer.

First, closure cap 20 is rotated up to a full rotation clockwise to achieve contact between stops 26 and 31, thereby rotating rotatable member 30 and stopping the arrow at the numeral 1. This aligns stud 36 with channel 22. Then, rotation of closure cap 20 in the opposite (counterclockwise) direction to position 2 will position stud 38 to pass axially through channel 21. In this embodiment, the embossed black line or arrow and the black numeral 1 comprise a first set of marks and the embossed black line or arrow and the black numeral 2 comprise a second set of marks.

Figs. 9 and 10 illustrate preferred modes of

marking the container and outer cap. In Fig. 9, one of the tabs 53' is relatively wider and differs from the other in shape. In Fig. 10, a circumferential collar or flange 56 is provided, i 5 Fig. 2 shows rotatable member 30 held in closure cap 20 by retainer ring 40 such that relative axial _* , movement of rotatable member 30 in closure cap 20 is prevented. Similarly, the axial dimensions of the closure cap sidewalls and container neck, as well as

10 the locations of stud 38 and rib 16 are such that axial movement of closure cap 20 is effectively prevented when the closure is in the locked condition. Thus only one type of relative movement, rotation, both of the rotatable member 30 and closure cap 20

15 relative to container 10 is possible when the closure is locked.

In another embodiment, a plurality of stop members is provided on one or both of the second and third relatively rotatable members. All of the stops

20 on at least one of the closures or related members have a ramp on the faces opposed to the stop faces. In this embodiment, the closures may be fabricated of a relatively clear material or other means may be used to allow visual observation, but not direct manual

25 manipulation, of the movable member.

In the preferred mode, the conventional unscrewing strategy is suggested to children by providing vertical seriations 54 on the outside surface of the closure cap similar to those provided

30 on conventional continuous threaded closure caps. The unscrewing strategy is thwarted by providing ramps 25 and/or 35 at one end of stops 26 and 31, respectively, < whereby closure cap 20 can be configured so as to be capable of driving rotatable member 30 only in the . 35 clockwise direction. Should the user attempt to rotate outer cap 20 sufficiently to drive rotatable member 30 in the counterclockwise direction, stop 26

would ride up ramp 35, slide across the top of stop 31 and drop-off the end of stop 31 without rotating rotatable member 30. In this way, only rotation of closure cap 20 relative to container 10 in one direction (clockwise when viewed from the top) is capable of causing rotatable member 30 to rotate relative to container 10. In an alternative embodiment (not shown) , at least one ramp is provided only at the other end of stop 25 or 35, thereby allowing rotation of rotatable member 30 in a counterclockwise direction only.

A strategy of simultaneous turning and lifting is thwarted by ensuring that when the closure is locked, studs 38 and 39 on closure cap 20 transfer an upward axial force applied to the closure cap to the container primarily directly to circumferential rib 16 instead of indirectly through ring 40 to rotatable member 30 and thence to rib 18. This is accomplished by choosing the axial locations of ribs 16 and 18, studs 36, 37, 38 and 39 and ring 40 such that, when an upward axial force is applied to closure cap 20 when it is on container 10 and locked, that the axial force is primarily resisted by closure cap 20 fastening means, first circumferential rib 16 and studs 38 and 39.

The "push and turn" opening strategy is thwarted by retaining rotatable member 30 in closure cap 20 between retaining ring 40 on inside sidewall 23 of closure cap 20 and pivots 61 and 62 located on the axis of rotation of rotatable member 30 and closure cap 20. Pivot 61 is provided on the inside surface of the top of closure cap 20. Pivot 62 is provided on the outside surface of the top of rotatable member 30. In an alternative embodiment, only one of the two pivots is provided. A single pivot would have to be longer axially to accomplish the same function. By providing at least one pivot, when downward axial

force is applied to closure cap 20 when it is on container 10, the axial force is primarily transferred to the rotatable member 30 in the vicinity of the axis of rotation of rotatable member 30 and distant from its sidewalls. In this way, concurrent downward axial force and rotation of closure cap 20 is ineffective in causing rotatable member 30 to rotate until stops 26 and 31 are properly engaged.

Tamper-resistance may be provided in a variety of ways. In one embodiment, a tubular shrink-wrap film

69 is applied to the package after closure cap 20 is installed and locked. The tube extends under collar 13 and over the top of closure cap 20. In another embodiment, an inner seal 72 comprising heat sealable polyester film and aluminum foil is bonded to the mouth of container 10 prior to installation of closure cap 20. Electromagnetic induction is used to activate the heat sealable film thereby bonding both seal components to the container mouth. In the preferred mode, shown in Figs. 1 and 4, a snap-off tab 70 is molded on the outer sidewall of closure cap 20. During the first unlocking of the closure, rotation of closure cap 20 causes tab 70 to break off upon impact with either tab 52 or 53 (Fig. 2) . Absence of tab 70 can reveal tampering in that it reveals that the closure has been unlocked after final assembly. In an alternative embodiment, also shown in Fig. 1, snap-off tab 71 protrudes upward from collar 13 of the container at the outer edge of the side wall of closure cap 20. Upon rotation of closure cap 20, a pointer 73 extending radially outward from the base of the cap, a variation of embossed pointer 57 in Fig. 8, for example, extending outward radially from at least the base of the sidewall of closure cap 20 breaks off the snap-off tab 71 upon impact.

Combination lock closure mechanisms can be unlocked either by random or systematic attempts to

try different combinations of relative orientations of closure structural elements. Combination lock mechanisms used on prior art child-resistant closures typically present the adult user with a straight- forward number of possible combinations for unlocking the closure. They usually did this by providing a single index mark on the cap and a plurality of numbers or letters on each tumbler. The closure was unlocked by aligning an appropriate number or letter on each tumbler with the single index mark. Rotation of a tumbler to a position wherein the single index mark was not aligned with a number or letter on the tumbler was not an option for unlocking the closure.

The combination lock closure mechanisms disclosed in the inventor's above-referenced patents and in

Figs. 1-7 do not present the adult users with a straight-forward, discrete number of possible combinations. This is the case because closure cap 20 and rotatable member 30 act as tumblers and the relative direction of the tumbler rotations is significant, which is not true with puzzle-lock type designs.

For the purposes of this disclosure, the term "effective width" of a channel means the difference between the width of a channel (e.g., channel 22) and the width of the stud (e.g., stud 36) that must be aligned with the channel. In the preferred mode, the "effective width" of channel 22 is wider than the effective width of channel 21. In this way, it is easier for a user with trembling hands to align stud

36 with channel 22 during the initial attempt to do so. The "effective width" of channel 21 can be relatively narrow because "searching" for this channel by the adult user is a practical option to precise alignment of stud 38 with channel 21.

Many variations of the invention will occur to those skilled in the art. All such variations within

the scope of the claims are intended to be within the scope and spirit of the invention. For example, while the tumblers used in the examples disclosed herein have studs as fastening means, the procedure is also , 5 applicable to the alternative tumbler designs disclosed in the above-referenced patents. », Furthermore, while the tumblers used in the examples disclosed herein are rotatable members, the method is also applicable to tumblers that are slidable members.

10 One variation of the invention (shown on Fig. la) involves providing a plurality of sets of channels, for example, two sets of channels (two channels in each rib located 180 degrees apart) instead of just one set. Adding a second set of channels would not

15 decrease child-resistance effectiveness if the effective width of the channels were reduced appropriately. To unlock the closure, the closure cap is first rotated clockwise past a first index to a second index. Then the closure cap is rotated

20 counterclockwise to the first index and lifted off the container. This version has the advantage of not requiring an initial full turn which is required with the version described above when the unlocking operation is initiated with the closure cap in certain

25 orientations. This will reduce the frequency of

"accidental" first time openings by adults who have really not yet learned how to correctly open the closure.

In another variation, only one stud or no stud is

30 provided on closure cap 20. The one stud may be the stud that is capable of passage through a channel (e.g., index stud 38) or it may be the circumferentially longer stud that is incapable of passage through a channel (e.g., stud 39). In this , 35 embodiment, the fastening means on container 10 and those on rotatable member 30 are used to prevent separation of closure cap 20 from container 10.

Closure cap 20 is accessible to direct manipulation but rotatable member 30 is not. Rotation of closure cap 20 in one direction drives rotatable member 30 to a designated position that unlocks the closure.

INDUSTRIAL APPLICABILITY The invention is capable of exploitation in industry as a closure for packaging of pharmaceutical products and toxic household chemicals. It can also be used to prevent access to the operating mechanism of child-resistant lighters and child-resistant belt buckles.

The closure parts may be fabricated using any conventional method. Thus, they may be fabricated by injection molding, blow molding, compression molding, transfer molding, casting, welding, machining, etc. As an example, the parts could initially be fabricated by injection molding and the channel effective widths modified by machining to dimension them so as to produce a selected width. Alternatively, the injection mold components used to form the parts could be initially machined to a "metal safe" condition to produce an initial version and then metal could be removed (to enlarge a stud width, for example) to produce a different channel effective width.