Child-proof Closures

Abstract

Closures of the so-called "tug-and-turn" type characterized as child-proof. These closures have two principal parts; an inner sleeve for engagement with the neck of the container, e.g., screw threads and an outer sleeve concentric with, longitudinally superimposed outside of, and releasably engaged with the container, by means of ratchet teeth or other forms of interfering projections on the outer sleeve and container respectively. Usually ratchet teeth are employed to permit the closure to be re-attached to the container without hindrance. The two sleeves are resiliently joined at some point along their common extent for joint rotating movement. Force applied axially to the outer sleeve will release the same from locked engagement with the container and the closure is then free for unscrewing. The present specification discloses improved means for resiliently joining the two sleeves to permit relative axial movement there between while providing for joint rotation of the sleeves as a unit.

Description

BACKGROUND OF THE INVENTION

A typical closure of the type aforesaid is disclosed in U.S. Pat. No. 3,422,978, granted to Edward C. Quackenbush on Jan. 21, 1969. In the embodiment of that patent the closure is in one piece and the connection between the sleeves comprises a plurality of resilient straps joining the two sleeves at the top. The straps may be likened to an inverted U with flexure occurring principally in the region of the bight. However, it has been found that, when the straps are made sufficiently rigid to enable torque applied to the outer sleeve to be transferred to the inner sleeve to detach the same from the neck of the container, the straps tend to resist the axial tugging force required to disengage the respective projections of the outer sleeve and container.

SUMMARY OF THE INVENTION

In its broad aspect, the present invention relates to improvements in the flexible connection between the two sleeves whereby flexure is distributed over a substantially greater distance thus to permit adequate transfer of torque applied to the outer sleeve to the inner sleeve and, at the same time, allow easier disengagement of the two sets of projections upon application of a much lower value of axially-directed tugging force. The rigidity in the flexible connection found adequate to foil a child's efforts to remove the closure can be readily incorporated without rendering the device so stiff as to interfere with operation by an adult.

To attain the foregoing dual advantage the inner and outer sleeves are joined by a plurality of annular segments, each of which may be regarded as a beam extending from one point on the perimeter of the outer sleeve to another point on the perimeter of the inner sleeve, which is angularly displaced therefrom. Thus, upon application of axially-directed tugging force the segments bend throughout their length in a manner similar to the behaviour of a cantilever beam. In this analogy the fixed end of the beam is the place of attachment of the segment to the latter being axially restrained by its engagement with the neck of the container, and the deflecting end of the beam is where the segment is attached to the outer sleeve and to which the tugging force is applied.

Where, in the description and claims, reference is made to "tugging" or "tugging force," these words are intended to emphasize a relationship between the parts of the closure which will resist a child's attempts to remove the same, as contrasted with the substantially increased force which an adult may exert without disproportionate strain, e.g., that which an average adult female may exert. A "child-proof" or "child-resistant" closure is defined in regulations of the Federal Food and Drug Administration.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a top plan view of a closure embodying the principles of the invention, showing the closure secured to the container;

FIG. 2 is a view similar to FIG. 1 but with the closure removed;

FIG. 3 is a bottom plan view of the closure;

FIG. 4 is a cross section taken on the line 4--4 of FIG. 1, the closure being in fully-tightened position;

FIG. 5 is a view similar to FIG. 4 but showing the respective projections of the closure and receptacle disengaged;

FIG. 6 is a top plan view of an alternative embodiment; and

FIG. 7 is a cross section taken on the line 7--7 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be described with reference to a bottle having a screw-threaded neck. However, it will be understood that any known means of engaging the closure with the bottle may be utilized.

By way of example there is shown a closure 10 preferably molded in one piece of resilient, but generally shape-retaining plastic composition, e.g., polyethylene, polypropylene and the like. The closure comprises an inner sleeve 12 having an internal thread 13 mating with a corresponding thread 14 formed on the neck 15 of the bottle 16, and an outer sleeve 21, both sleeves being concentric with the neck 15. The two sleeves depend from a top 23 which may have any desired configuration on the upper surface thereof which is within the flexible segments to be described, e.g., crowned, and likewise as to the outer surface of the sleeve 21 which preferably has knurling or other form of discontinuous surface for implementing gripping by the fingers. If desired a gasket (not shown) of paper or other medium may be interposed between the lower face of the top 12 and the rim of the neck 15.

The outer sleeve 21 is provided with a plurality of projections 31, e.g., ribs, which have a transverse cross section best seen in FIG. 3, i.e., of hooked form. Although only the lower portion of these ribs is utilized, fabrication of the molds and stripping of the piece part from the mold is facilitated by so doing. These projections cooperate with hook-like abutments or projections 33--33 outstanding from the bottle 16 (FIGS. 2 and 4). Thus, as the closure is screwed clockwise on the neck 15 (FIG. 2) the projections 31 ride or "click" over the projections 33--33 until the closure makes a tight seal on the neck. Any attempt to simply unscrew the closure is thwarted by interference of the two sets of projections, the hook-like form whereof presents reliable engagement, far beyond the strength of a child of tender years or even beyond the ability of an adult who might, for no good reason, attempt to remove the closure by conventional effort. The means for releasing the closure for unscrewing will be described shortly.

In order to prevent radial squeezing of the sleeve 21 from releasing the projections 31 from the projections 33 thereby to defeat the purpose of the latter, it is preferred to provide at least one pair of projections 35--35 (FIGS. 2 and 4), against which the sleeve 21 will abut if this latter is squeezed transversely while applying tugging force.

To enable the outer sleeve 21 to be released from locked condition, the top 23 is slotted, as shown, to define a plurality of flexible straps or ligaments 41. In the example, the straps have an arcuate configuration; specifically, circular. However, other configurations of strap may be used provided that the same may flex in a direction which is substantially axially of the closure. In the embodiment of FIG. 1 the straps are alternated. The members of each pair of adjacent straps are merged at one end into the top 23 at a central point 42. The remote end 43 of each strap is merged into the top 23 radially outwardly of the strap 41. It will be clear that an outer annular portion 46 of the top 23 carries the sleeve 21 and that this, by reason of the straps intermediate the two sleeves, has a flexible connection with the sleeve 12. Accordingly, an upward and sustained tug on the sleeve 21 will release the teeth 31 from the abutments 33 to permit unscrewing of the closure (FIG. 5). Obviously, both the axial and rotational forces occur virtually concurrently. An adult will have the strength and intelligence to carry out this dual operation; a child, by reason of his immaturity, limited strength and poor coordination is not likely to succeed.

Since, when axial force is applied, the straps 41 will bend along a distance which extends arcuately over some appreciable angle, the required axial displacement of the outer sleeve 21 may be produced with far less effort than similar closures heretofore known. Stated otherwise, the invention arrangement can be made as relaxed or as stiff as the circumstances dictate without increasing the diameter of the closure. The degree of stiffness is readily varied by change in the transverse cross section and dimensions of the strap and/or the kind of material employed.

FIGS. 6 and 7 show a modified form of the closure wherein the outer sleeve 21a is considerably foreshortened in height and the sleeve 12a forms an upward extension thereof. This alternative leaves the mechanical function unchanged but is somewhat more compact and esthetic. FIG. 6 also shows a modified form of strap 41a, the construction and function of which is believed to be clear in view of the description of the straps 41.

It will have been noted that both forms of closure shown and described have the important advantage that they may be attached to the container by the rotating chuck of conventional capping machines, there being no exterior protrusions to interfere.

Claims

I claim:

1. In combination, a container having a screw-threaded neck and a closure for said neck, said closure comprising an inner sleeve having an internal screw thread engageable with said neck thread for attachment and removal of the closure, an outer sleeve exteriorly of said inner sleeve, concentric with, spaced therefrom and connected thereto for joint rotation of both sleeves, said outer sleeve having at least one internal projection and said container having at least one external projection selectively abuttable with said outer sleeve projection when the closure is rotated on the neck to open condition, said projections having respective configurations allowing non-abutting rotation of the outer sleeve relative to the container only when the closure is rotated to closed condition, the means connecting said two sleeves adapted to permit axial movement of the outer sleeve to disengage the projections, the improvement in which said joining means comprises a plurality of resiliently deformable, elongated straps located in the annular zone defined between the two sleeves, one end of each strap being joined to the outer sleeve and the other end to the inner sleeve, the principal plane of each strap being perpendicular to the common axis of the sleeves in the normal condition of the sleeves, and displaceable out of said perpendicular position upon relative axial displacement of the sleeves, each strap being arcuate between its respective junctions with the sleeves.

2. The improvement in accordance with claim 1 wherein there are an even number of straps, the adjacent ends of each pair having a common junction with the outer sleeve and the other ends thereof being joined to the inner sleeve.

3. The combination in accordance with claim 1 wherein the outer sleeve is axially shorter than the inner sleeve.

4. The combination in accordance with claim 1 further chatacterized in that the container is provided with abutment means to preclude radially-inwardly directed forces applied to the outer sleeve while the outer sleeve is in non-rotative condition, from collapsing said outer sleeve whereby said projections may be caused to disengage and free the closure for rotation.

5. The combination in accordance with claim 4 in which the abutment means are substantially aligned axially with the projections.