The invention relates to a snap-on closure adapted for use with a container available as a child-resistant package. More particularly, the improved snap-on closure of the invention has a feature which retains the integrity of the seal and snap-on fitment with the container neck finish while rendering the closure easier to open in the unlocked position.
Child resistant snap closures are widely known and are of many different varieties. In its simplest form, such as that disclosed in U.S. Pat. No. 3,627,160, the closure skirt has an inner locking lug adapted to be aligned upon closure rotation with a notch, i.e., a gap or discontinuity located in an annular locking ring on the neck finish of the container to permit closure removal. In such position, known as the “fire” position, the closure is effectively unlocked to facilitate its removal. The closure skirt likewise has a pair of circumferentially extending snap beads on its inner wall with the midpoint diametrically opposite the lug for snap locking engagement with the annular locking ring. The locking lug lies in the same plane as the locking beads to likewise snap fit beneath the locking ring when the cap is manually pressed down over the container neck.
The closure skirt has an outer finger tab in alignment with the locking lug to provide a bearing surface for the operator's thumb or finger in lifting off the closure when the thumb tab and locking lug are oriented into alignment with the notch in the annular locking ring. Indicia which may be in the form of a triangle serving as a pointer is normally provided on the container neck to indicate when the locking lug is accurately in registry with the notch or gap of the annular locking ring.
The closure skirt is relatively stiff and rigid although sufficiently resilient such that it flexes radially outwardly upon closure removal as co-acting cam surfaces between the snap beads and the locking ring permit the beads to ride upwardly over the major diameter portion of the locking ring in the process of disengaging the beads from the ring during closure removal in the fire position. However, the inherent hoop strength offered by the closure skirt limits its resilient expansion, thus rendering the closure difficult to remove. In particular, elderly people or those having finger dexterity or strength problems have difficulty opening such a package because of the force required, especially for the removal of small-sized snap-on closures from small-sized containers. Because of their smaller size, such closures resist flexing to a greater extent compared to larger-sized closures, hence requiring a greater removal force.
Also, during closure removal, the locking lug impacts against the outer peripheral edge of the neck finish, despite the unobstructed passage of the locking lug through the notch in the annular locking ring. Because the locking lug is located at a spaced axial distance from the closure end wall and is in the same plane as the snap beads (to underlie the locking ring in the snapped-on position), the lug strikes the upper peripheral edge of the neck finish at the container opening as the closure is tilted upwardly. The lug moves in an arc as the opposite side of the closure is used as a fulcrum. This impact against the neck finish peripheral edge offers some resistance in the opening process as the lug rides upwardly over such edge. During this process the closure skirt at the finger tab elastically expands radially outwardly as limited by the inherent hoop strength of the skirt.
This resistance may be overcome by those having the strength and finger dexterity to remove the cap in the fire position without much difficulty, although it may present a problem for others.
Another closure design is disclosed in U.S. Pat. No. 5,292,017. This cap closure is provided with at least one break or disruption in the skirt to make it easier to open and close the closure by reducing the hoop tension.
However, there remains a need for an improved, easily-opened and —closed safety closure that is child resistant.
An embodiment of the present invention provides a child-resistant, snap-on closure for snap fitment with the neck finish of the container.
The improved snap-on closure is simple and economical to produce and operate, yet highly effective in rendering the snap closure easier to remove in the fire position while retaining its child-resistant capability.
In this embodiment, the closure is a cap that snaps over the opening of a package. The neck finish of the container has an annular locking ring having a notch. The closure has a lug on the interior of the skirt and two snap beads centered diametrically opposite the locking lug on the interior of the skirt. The snap beads are located in the same plane as the locking lug. The snap beads and the lug snap-fit over the annular locking ring to secure the closure on the container. In the fire position, the lug is co-located with the notch on the annular ring to allow removal of the closure.
In an embodiment, the closure also has a crown that tapers upwardly and outwardly from the skirt to make grasping the closure easier. The crown provides additional leverage than could be obtained by the prior art closures, thus reducing the lift-off force. A finger tab is located on the outside of the skirt in alignment with the locking lug to indicate the location of the lug. The notch in the annular ring is in alignment with indicium on the container. Thus, to put the closure in the fire position, the cap is rotated as required to put the finger tab into alignment with the indicium on the container, thus putting the locking lug on the closure into alignment with the notch in the annular ring.
In an optional embodiment, the closure skirt may be provided with at least one accordion segment that permits the skirt to resiliently flex radially outwardly beyond the limits of its inherent hoop strength as the snap beads ride upwardly over the major diameter portion of the locking ring in the process of closure removal at the fire position. The outward expansion or flexing of the skirt as facilitated by the optional accordion segments reduces the hoop tension, thereby permitting the snap beads to more readily disengage from the annular locking ring in this optional embodiment.
If desired, at least one accordion segment may be provided at one or more desired locations in the closure skirt for relaxing the hoop strength to facilitate easier disengagement of the snap beads/locking lug. Locating the optional accordion segment at or adjacent to the finger tab enables the skirt portion at the tab to flex radially outwardly as the locking lug impacts against the upper peripheral edge of the neck finish at the container opening during the process of closure removal in the fire position. When the inherent hoop strength of the closure skirt is relaxed or reduced by the provision of the at least one optional accordion segment, the locking lug can more easily ride up over the upper peripheral edge of the container neck finish to make closing easier.
Because the closure skirt is resilient, the optional accordion segment in the skirt will not, when present, interfere with the ability of the closure skirt to tightly and securely snap fit with the annular locking rib on the neck finish. As will be described more fully hereinafter, more than one accordion segment in the closure skirt can be provided and different forms and shapes thereof are possible in different embodiments.
In an embodiment, the cap is useful as a simple snap-on cap that is not child-resistant.
In the drawings, like reference characters refer to like and corresponding parts throughout the several views.
A prior art child resistant snap closure 20 is shown in
The neck finish has a radially outwardly extending annular locking ring 25 with at least one notch 26 therein forming a gap, and triangular indicia 27 or the like on the neck finish in alignment with the notch.
The closure has an end wall 23 and a peripheral annular skirt 24 generally of uniform cross-section. Skirt 24 of the closure has a radially inwardly extending locking lug 28 and a radially outwardly extending finger tab 29 in alignment with the locking lug. The closure skirt likewise has radially inwardly extending rib structure which may be in the form of spaced snap beads 31 having a midsection diametrically opposite locking lug 28. The snap beads are circumferentially spaced from the locking lug and lie in substantially the same radial plane therewith.
The closure is snap fitted to the neck finish as locking lug 28 and snap beads 31 engage beneath locking ring 25 upon manual application of a downward force against end wall 23 with the closure in any rotative orientation relative to the container except for its orientation shown in
In the rotative position of
The locking lug and/or snap beads as well as the locking ring are appropriately rounded to effect cooperative camming action as the cap is both snap fitted to the neck finish and as the closure is removed therefrom. The closure skirt resiliently expands upon flexing during the process of both snap fitting the closure in place and upon closure removal.
The cap skirt has an inherent hoop strength which limits resilient expansion and flexing of the skirt in a radially outwardly direction upon snap fitting the locking lug and snap beads to the locking ring and upon releasing the snap beads from the locking ring. Further, the finger tab is close to the locking ring, providing little leverage for removal of the closure. This structural characteristic of the closure oftentimes renders it difficult to open and remove the closure by especially the elderly and/or those lacking finger dexterity and/or strength. Also, closures of a relatively small size are found difficult to open due to the added stiffness of the small sized closure.
Therefore, a second prior art closure, illustrated in prior art
Thus, with locking lug 28 aligned with notch 26 in readiness for closure removal, i.e., in the fire position, as shown in
Although this second prior art closure is somewhat easier to operate than the first prior art closure, it is still less than satisfactory. The finger tab is located in the same position relative to the locking ring and snap beads, thus providing little leverage, and thus requiring great force, for removal. Also, slots cut into the skirt, similar to those indicated in
An embodiment of the invention is an improvement over these prior art closures. This embodiment includes a crown design that adds a large, smooth surface on the outside of the closure. This surface enlarges the diameter of the closure, as the crown extends upwardly and outwardly from the top of the closure. This feature moves the lift-off movement point upwardly and laterally further away from the locking ring. Moving the fulcrum point in this way increases the leverage the user has to snap the closure off the top of the container. Increasing the leverage decreases the lift-off force required. The crown also provides a slightly larger finger tab. Also, vendors prefer a closure having the same diameter as the container and this crown design can match container diameter. Optionally, at least one accordion segment is incorporated into the skirt of the closure to further reduce the lift-off force required to open the container.
In an embodiment, the indicia on both the closure and the container are made safer by elimination of sharp edges and corners to reduce any tendency to cause injury to the user while making alignment in the fire position easier in difficult conditions as, for example, in low light conditions, or when the user has limited ability to align the closure into the fire position. Thus, all corners and edges of the indicia on both the closure and the container are rounded and have no sharp edges. This design thus essentially eliminates the opportunity to cut or break the skin when handling the container or closure.
Optionally, to further make the indicia safer, an embodiment of the invention forms the indicia from a composition softer and more flexible than the more rigid material from which the container and closure are made. In accordance with this embodiment, material softer than that used to form the container and the closure is overmolded onto the indicia. The skilled practitioner knows methods by which such a flexible plastic can be over-molded onto the container, closure, or both, in accordance with the guidance provided herein.
As shown in
Further, locking lug 28 is shown in alignment with indicium 29. Locking lug 28 snaps over shallow locking rib segment 50. Snap beads 31 are shown centered around a point diametrically opposite the locking lug. Optional accordion sections 35 also are shown, as is crown 40. Crown 40 extends above end 23 of the closure. The greater diameter at the top of crown 40, together with the location thereof above end 23 of the closure and a larger finger tab 29, provide a different fulcrum point that provides additional leverage that makes removal of the closure easier than either of the prior art disclosures.
Snap beads 31 are longer than notch 26 is wide so that the cap cannot be removed by aligning a snap bead with the notch 26. Locking lug 28 is only slightly narrower than notch 26 so that the lug can move through notch 26 and over shallow locking rib segment 50 for removal.
Locating optional accordion section 35 closer to the snap beads enables the cap skirt to flex radially outwardly in the process of closure removal.
The conventional child-resistant snap closure package presents another problem which oftentimes renders it difficult for some operators to remove the closure. For example, in the process of removing the prior art closure from its
In an optional embodiment of the invention, an accordion section is located adjacent one or both sides of finger tab or indicium 29 to further reduce the force required to open the closure. This feature permits the closure skirt at the finger tab to flex radially outwardly. As lug 28 impacts against edge 36 in the process of opening the closure, the interference between lug 28 and edge 36 is ameliorated by the accordion sections, which enable easier opening of the closure. After opening, the closure skirt at the finger tab is used to return to its normal position by the inherent characteristics of the known plastic material employed for the snap closure.
Another optional embodiment of the invention includes lugs 53 illustrated in
From the foregoing, it can be seen that a simple yet highly effective improvement for a child resistant snap closure has been provided. The crown provides additional leverage for removal and to facilitate easier opening. Yet, in the snap-fitted condition of the closure, the snap beads and locking lug tightly and positively inter-engage with the annular locking ring on the neck finish for locking and sealing the closure in place. The shallow locking rib segment obscures the opening notch at the fire position to make it more difficult for a child to open the closure inappropriately.
In particular, the safely-shaped alignment indicia reduce energy and afford easier identification of the fire position. The location and diameter of the crown makes removal easier. Also, the cap can be used as a non-safety cap by engaging lugs on the crown with the annular locking ring. Obviously, many other modifications and variations of the present invention are made possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
The present application is a non-provisional application of Provisional Application No. 60/949,406 filed Jul. 12, 2007, the entire contents of which are incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60949406 | Jul 2007 | US |