Child-resistant closure for a container having a threaded neck

Abstract

A child-resistant closure for a container having a threaded neck. The closure comprises an inverted cup-shaped cap having a disc-like top and a tubular skirt which has mating threads on its interior. A circular sealing means such as a liner is positioned interiorly of the cap to seal the end of the container neck when the cap is turned onto the neck in normal closed position. The lower margin of the cap skirt and the adjacent shoulder portion of the container have interengaging locking means for preventing removal of the cap unless the lower portion of the cap skirt is flexed upwardly to disengage the locking means. One of the locking means consists of a plurality of circumferentially spaced first elements and the other of a circumferentially extending series of opposed elements. The locking means engage when the cap is turned onto the container to at least normal closed position and also if the cap is turned beyond normal closed position thus to insure child-resistant locking even in the latter situation.

Description

BACKGROUND OF THE INVENTION

Many child-resistant closures for containers having threaded necks have been designed comprising cooperating locking means on the caps and the containers which are engaged when the caps are turned onto the containers to normal closed positions and which thereafter resist retrograde rotation of the caps relative to the containers in order to render the closures child-resistant. Some of these child-resistant closures have included deformable caps which are squeezed inwardly to flare their edges outwardly to disengage the locking means; others have included deformable bottle shoulders which, similarly, are squeezed inwardly at the locations of the locking means to disengage them; others have comprised one or more radially outwardly extending tabs at the lower edges of the cap skirts which engage stops or shoulders on the container and must be lifted upwardly to disengage them in order to remove the caps.

If it were possible to commercially manufacture the caps and containers without any appreciable tolerances in their constructions, child-resistant closures comprising interengaging locking means which are locked precisely at normal closed position would be satisfactory. However, because of manufacturing tolerances in the height and relative angular positions of the interengaging locking means, when these tolerances cumulate with respect to any particular cap and container, a new problem arises.

In order to be commercially feasible, such child-resistant closures must be capable of being closed on automatic capping machinery now in existence in most of the plants where such containers are filled. Such automatic capping machinery turns the caps onto the containers with a predetermined torque that is selected to insure that the caps go onto the containers a distance sufficiently far to engage their internal sealing means with the open necks of the containers thus to prevent leakage of liquids from the containers. As a result of the aforementioned cumulation of tolerances, however, many caps are turned onto their containers to relative angular positions differing from the relative angular positions at which other caps are turned onto the containers. Where child-resistant locking means are present this results in many cases in turning the caps beyond the normal closed positions with the locking means turned beyond each other angularly. Such an excessive rotation of a cap relative to a container may also occur when the cap is restored to the container by an adult having strength in excess of that necessary to turn it onto the container merely to the normal closed position.

When such a cap is rotated onto its container through a distance angularly beyond the child-resistant locking means, a child may be endeavoring to open such a container and may rotate the cap in a retrograde direction until the locking means engage. While the child cannot remove the cap by reason of the interengaging locking means, this retrograde rotation may result in a leaking container. The initial rotation of the cap onto the container beyond the normal closed position will, in most instances, press the circular sealing liner to a degree beyond ability to restore and, as a result, when the cap is rotated backwardly to the normal closed or locked position, the sealing liner may not restore to its full thickness and may not continue to seal the open end of the container neck.

It is therefore the principal object of the instant invention to provide a child-resistant closure for a container having a threaded neck and comprising interengaging child-resistant locking means which compensates for the likelihood that many of the caps embodying the invention may be rotated onto the container necks to a relative angular position beyond the normal closed position at which the child-resistant locking means engage.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a fragmentary side view in elevation, with parts broken away, of a child-resistant closure combination embodying the invention;

FIG. 2 is a top plan view of the closure combination of FIG. 1;

FIG. 3 is a horizontal, sectional view taken along the line 3--3 of FIG. 1;

FIG. 4 is a fragmentary, vertical sectional view taken along the line 4--4 of FIG. 1;

FIG. 5 is a horizontal, sectional view taken along the line 5--5 of FIG. 4;

FIG. 6 is a fragmentary view, partly in elevation, illustrating a modification of the interengaging locking means of the embodiment of FIGS. 1-5, inclusive;

FIG. 7 is a fragmentary view in side elevation of a second modification of a child-resistant closure combination embodying the invention;

FIG. 8 is a top plan view of the closure combination shown in FIG. 7;

FIG. 9 is a view similar to FIG. 7, but of a third modification of the invention;

FIG. 10 is a top plan view of the closure combination shown in FIG. 9;

FIG. 11 is a view similar to FIGS. 7 and 9, but of yet another embodiment of the invention;

and FIG. 12 is a fragmentary top plan view of the closure combination shown in FIG. 11.

DESCRIPTION OF PREFERRED EMBODIMENTS

A child-resistant closure combination embodying the invention as illustrated in all of the drawings of the instant application basically consists of a container having a threaded neck and an inverted cup-shaped cap which has a tubular skirt with internal threads that mate with the threads on the neck of the container. In all of the embodiments, it is intended that the cap shall be turned on the neck of the container to a distance sufficient to slightly compress a disc-like, or circular, liner located interiorly of the cap against the open neck of the container in order to seal the container to prevent the escape of liquid contents. In all of the embodiments the lower margin of the cap skirt and the container have cooperating child-resistant locking means so that when the cap is turned onto the container to its normal closed position, the locking means engage and cannot be disengaged to allow removal of the cap without an understanding of a secondary disengagement movement. Furthermore, in order to effect the disengagement movement, greater strength or a larger span of the fingers is required than usually is present in a child of tender years.

A first embodiment of the invention is illustrated in FIGS. 1-5, inclusive. In this child-resistant closure combination, a container 20 has an externally threaded neck 21 and a generally inwardly extending shoulder 22 connecting the upper portion of the body of the container 20 at its neck 21. A one-piece cap 23 has a disc-like top 24 and a tubular skirt 25. The inner surface of the skirt 25 has threads which mate with the threads on the neck 21.

In this embodiment there is a planar annular flange 26 at the lower margin of the cap skirt 25 which is connected to the margin of the skirt 25 by a thinner section generally indicated by the reference number 27.

A plurality of downwardly and radially extending teeth 28 are formed on the underside of the flange 26, each tooth 28 having a generally vertical rear surface 29. The rear surfaces 29 are circumferentially spaced from each other and function as the first elements of the child-resistant locking means. Opposed elements of the child-resistant locking means are illustrated as consisting of two opposite sets of two opposed teeth 30 each. The two sets of opposed teeth 30 (FIG. 5) are generally opposite to each other around the container shoulder 22, but are positioned slightly off the diameter so that each of the two sets of opposed teeth 30 is engaged sequentially but not at the same time by the first teeth 28 of which there also are two sets on opposite sides. By reason of the diametrically opposed positions of the two sets of first teeth 28 on the cap flange 26, and the general but not exact diametrical positioning of the two sets of opposed teeth 30 on the shoulder 22 of the container 20, when the cap 23 is rotated onto the container neck 21, the teeth of each of the sets 28 alternately engage with their respective opposed teeth 30 so that no matter what the final relative angular position between the cap 23 and container 20 may be when the cap 23 is rotated onto the neck 21, for example, by automatic capping machinery, at least one of the first element teeth 28 will be firmly engaged with at least one of the second or opposed element teeth 30.

The seriatim engagement of the two elements of the child-resistant locking means thus accomplishes two objectives. First, it insures engagement of the locking means even if the manufacturing tolerances of the cap 23 and container neck 21 cumulate in one pair and oppose each other in another pair. Second, it provides for turning the cap 23 slightly farther onto the neck 21 to compensate for gradual compression of a circular sealing means 31 positioned interiorly of the cap 23 against the open neck 21 of the container 20. This second aspect of a child-resistant closure combination embodying invention becomes more important when it is realized that sealing means of the liner type such as the sealing means 31 illustrated in FIGS. 1-5 are fabricated from materials which begin to take a "set" upon repeated reapplication of compressive forces against their margins created when the cap 23 is tightened back onto the container neck 21. The seriatim engagement of the first and opposed elements of the child-resistant locking means also insures child-resistant locking even though the cap 23 is restored onto the container 20 by a strong adult who might turn the cap 23 to a further angular relationship with respect to the container 20.

In order to disengage the child-resistant locking means comprising the first element teeth 28 and opposed element teeth 30, it is necessary to flex the margins of the flange 26 above the sets of teeth 28, upwardly, as illustrated in FIG. 4. To this end, the material from which the cap 23 is molded should be at least semi-flexible and it may have a portion 27 of reduced thickness in order to facilitate bending the flange 26 upwardly at the points indicated by the legend "Lift Here" which is shown in FIG. 2 as being located above the respective sets of first element teeth 28.

By reason of the size of the flange 26 and the stiffness built into the thinner section 27, the size of a hand of a person seeking to open the child-resistant closure combination of invention may be taken into account and also the strength of the fingers of that person. It is thus simple to so design this embodiment of the invention so that a child of tender years, say less than age 6, encounters significant difficulty in lifting the margins of the cap flange 26 a distance sufficient to disengage the child-resistant locking elements, comprising the first teeth 28 and the opposed second teeth 30, so as to permit retrograde rotation of the cap 23 relative to the container 20 and thus access to its contents. On the other hand, the size and resistance to flexing can be so pre-set as to enable an adult or an older child readily to open the container.

FIG. 6 illustrates a modification of this embodiment of the invention wherein the first element teeth 28, indicated by the reference number 28a again cooperate with upwardly extending second element opposed teeth indicated by the reference number 30a. In this modification, however, rear surfaces 29a of the first element teeth 28a are undercut relative to the second element teeth 30a as are opposed surfaces 32a of the second element opposed teeth 30a. Thus, after engagement of the two elements of the child-resistant locking means, viz., the first element teeth 28a and second element teeth 30a, when a child endeavors to turn the cap 23a in a retrograde direction relative to the container neck 21a, the two opposed child-resistant locking elements lock together more tightly by reason of the camming action of the relatively undercut cooperating faces 29a and 32a.

FIGS. 7 and 8 show a second embodiment of the invention in which a cap, generally indicated by the reference number 33 has a generally planar marginal flange 34 similar to the flange 26 of FIGS. 1-6. In this instance, however, the cooperating child-resistant locking means consists of first elements which are openings 35 in the flange 34, each of the openings 35 having a generally radially extending surface 36. The second set of opposed elements in this embodiment consists of upwardly extending teeth 37 located on a shoulder 38 of a container 39. The second or opposed elements, i.e., the teeth 37, also have generally radially extending faces 40 which engage with the surfaces 36 of the openings 35. The first elements 35 are located on opposite sides of the cap 33 and extend in two circumferentially spaced series and the second elements, i.e., the teeth 37, similarly are sequentially engaged alternately, when the cap 33 is rotated onto the container. As in the earlier embodiment of the invention, the flange 34 must be flexed upwardly (dotted line indication in FIG. 7) to disengage the child-resistant locking elements in order to remove the cap 33.

A third embodiment of the invention is illustrated in FIGS. 9 and 10. In this embodiment, a cap 41 has a generally planar flange 42 at its lower margin but the flange 42 is not continuous, thus providing at least one set of independently flexible tabs 43. Each of the tabs 43 has a downwardly extending tooth 44 on its under surface, the teeth 44 functioning in this embodiment as the first element of the child-resistant locking means. In this embodiment a series of notches 45 is molded in a shoulder 46 of a container 47 so that the notches 45 act as the second or opposed elements of the child-resistant locking means for sequential engagement by the teeth 44 on the individual tabs 43 as the cap 41 is rotated onto the container 47.

Still another embodiment of the invention is illustrated in FIGS. 11 and 12 in which a cap 48 has a plurality of individual tabs 49 at the lower margin of its skirt rather than having a continuous flange extending around the margin of its skirt. In common with the earlier described embodiments of the invention, the tabs 49 function as first elements of the child-resistant locking means for cooperation with second or opposed elements thereof, in this case, upwardly extending lugs or teeth 50 formed on a shoulder 51 of a container 52.

In the embodiments of the invention illustrated in FIGS. 9-10 and 11-12, in contrast to the earlier described embodiments of the invention of FIGS. 1-6 and 7-8, respectively, the first elements of the child-resistant locking means, i.e., the tabs 43 or 49, must be individually and simultaneously lifted upwardly to insure complete disengagement with their respective opposed or second elements, i.e., the notches 45 or the teeth 50. The size spacing, and resistance to deformation of these tabs are so selected that the hand and fingers of a small child are incapable of lifting them to a degree sufficient to disengage the child-resistant locking means to enable removal of the respective one of the caps. Similarly to the earlier embodiments, the spacing and serial arrangement of the interengaging locking means are such that they compensate for the gradual set in an interior sealing means such as a disc liner, and also for different angular positioning of the caps relative to the containers, by reason of tolerance variation or the exertion of varying degrees of recapping force.

Claims

What I claim is:

1. A substantially leak-proof and child-resistant closure combination, said combination comprising,

a. a container having a tubular neck, a hollow body and a generally inwardly extending shoulder between the upper portion of said body and the base of said neck,

b. a one-piece cap for said container, said cap having a disc-like top and a tubular skirt,

c. cooperating threads on said neck and said cap skirt for retaining said cap on said neck,

d. circular sealing means on the interior of said cap and engageable with said tubular container neck for sealing said container neck when said cap is in normal closed position on said container,

e. and cooperating child-resistant locking means on said cap and said container shoulder engageable when said cap is rotated at least to normal closed position relative to said container neck, said child-resistant locking means consisting of

f. a plurality of circumferentially spaced radially extending first elements integral with and at the lower margin of said cap skirt and

g. a circumferentially extending plurality of opposed elements formed on said container shoulder and engageable with said neck to at least normal closed position thereon,

h. the elements in one of said plurality of elements being offset circumferentially from diametric opposition,

i. the element-comprising portion of said container skirt being resiliently deformable upwardly for disengaging said locking means.

2. A closure combination according to claim 1 in which the cap has a radially oriented flange at the lower margin of the skirt and the first elements of the child-resistant locking means are a part of said flange.

3. A closure combination according to claim 2 in which the first elements are teeth extending downwardly from the underside of said flange.

4. A closure combination according to claim 2 in which the first elements are apertures in the flange.

5. A closure combination according to claim 1 in which the first elements of the child-resistant closure are individually flexible, circumferentially spaced, radial tabs on the lower margin of the cap skirt.

6. A closure combination according to claim 5 in which the tabs have downwardly projecting teeth on their undersides and the opposed elements are upwardly open recesses in the shoulder portion of the container.

7. A closure combination according to claim 1 in which there are two sets of cooperating child-resistant locking means on the cap and the container, the elements in each of said sets being diametrically opposed and in which both must be disengaged for removing said cap from said container.

8. A closure combination according to claim 1 in which the child-resistant locking means are opposed sets of tooth-like projections on the cap and the container and the sets of teeth are undercut relative to each other whereby retrograde rotation of said cap relative to said container more tightly engages said projections.