Safety cap for threaded closure

Abstract

A safety closure for a container having an externally threaded neck. The closure includes an inner member that is internally threaded for application to the neck of the container, and an outer closure member fitted over the inner member and holding the inner member captive therein. The outer member fits loosely over the inner member so that the outer member is normally free for rotation relative to the inner member and is also free for limited telescopic movement over the inner member. Lugs are provided on the inner surface of the outer member, and recesses are formed in the outer surface of the inner member, so that when the outer member is lifted, pressed radially inwardly, and rotated the lugs mesh with the recesses to provide engagement between the inner and outer members so that the inner member can be removed from the container by continued rotation of the outer member. Thus, simultaneous application of lifting, radially inwardly compressive, and rotational forces to the outer member is required in order to remove the closure from the container.

Description

The present invention relates generally to container closures and, more particularly, to an improved safety closure for containers having externally threaded necks.

It is a primary object of this invention to provide an improved safety closure which requires such a combination of manipulations to remove it that removal of the closure by a child is rendered extremely difficult or even impossible. A related object is to provide such a safety closure which requires conscious effort to remove it so that accidental removal is virtually impossible.

It is another object of the invention to provide an improved safety closure of the foregoing type which can be economically mass produced from inexpensive plastic materials.

A further object of the invention is to provide such an improved safety closure which can be easily and quickly assembled.

Other objects and advantages of the invention will be apparent from the following detailed description and the accompanying drawings, in which:

FIG. 1 is a perspective view of a safety closure embodying the invention applied to a standard container;

FIG. 2 is an enlarged section taken along line 2--2 through the safety closure in FIG. 1, with the outer member of the closure in its normal inoperative position;

FIG. 3 is the same section shown in FIG. 2 but with the outer member of the closure in an intermediate position;

FIG. 4 is the same section shown in FIG. 2 with the outer member of the closure in the final operative position required for removal of the closure; and

FIG. 5 is a section taken along line 5--5 in FIG. 2.

While the invention will be described in connection with certain preferred embodiments, it will be understood that it is not intended to limit the invention to these particular embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalent arrangements as may be included within the spirit and scope of the invention.

Turning now to the drawings and referring first to FIGS. 1 and 2, there is shown a standard container 10 which is open at the top of a neck 11 having external threads 12 formed as an integral part of the outer surface thereof. It will be appreciated that the entire container 10, including the neck 11 and the threads 12, can be formed as a unitary article of molded plastic, for example. The open neck 11 of the container 10 is closed by a removable safety closure 13 comprising an internally threaded inner member 14 threaded onto the container neck 11 and an outer member 15 telescoped over the inner member 14. While the outer closure member 15 is free for limited telescoping movement relative to the inner member 14, a horizontal flange 16 formed on the lower edge of the outer member 15 extends radially inwardly beneath the inner member 14 so that the outer member 15 can never be entirely removed from the inner member 14. That is, the inwardly extending flange 16 on the lower edge of the outer member 15 serves to limit the degree of axial telescoping movement permitted between the outer member 15 and the inner member 14.

In accordance with one important aspect of the present invention, a safety closure is provided by forming an interface between the inner and outer closure members which requires a combination of lifting, radial compression, and twisting forces to engage the two closure members so that the inner member can be threaded off the container. Thus, in the illustrative device, a pair of diametrically opposed recesses or notches 20 are formed in the outer sidewall of the inner member 14 for cooperating with a corresponding pair of diametrically opposed lugs 21 formed on the inner sidewall of the outer member 15. When the outer member 15 is in its lowermost position, where the flange 16 is spaced away from the bottom of the inner member 14 and resting on the top of the container 10 as illustrated in FIG. 2, the lugs 21 are axially spaced away from the recesses 20. In addition, the lugs 21 are radially spaced away from the recesses 20 so that the outer member 15 is freely rotatable relative to the inner member to normally prevent rotation of the inner member.

In order to remove the closure from the container, the outer member 15 must first be raised to its uppermost position as illustrated in FIG. 3, where the flange 16 engages the bottom of the inner member 14; the lugs 21 are located for axial alinement with the recesses 20 when the member 15 is in its raised position. Next, the sidewalls of the outer member 15 must be flexed inwardly by applying radially compressive forces to the outside of the member 15 as indicated by the arrows in FIGS. 4 and 5, while simultaneously twisting the member 15 to bring the lugs 21 into circumferential register with the recesses 20 so that the lugs 21 snap into the recesses 20. This meshing of the lugs 21 with the recesses 20 provides latching engagement between the inner member 14 and the outer member 15, as illustrated in FIG. 4, so that continued rotation of the outer member 15 also rotates the inner member 14 to remove the entire closure from the container 10. Thus, it can be seen that a combinatijon of lifting, radially compressive, and rotational sources are required in order to engage the inner and outer closure members 14 and 15 so that the safety closure 13 can be removed.

In accordance with a further specific feature of the invention, indicia are provided on the outer sidewalls of the outer closure member 15 to indicate the location of the lugs 21 on the inner sidewall thereof. Thus, as illustrated in FIG. 1, a pair of patterned areas 22 are formed as opposite sides of the outer member 15 directly adjacent the inside lugs 21 to indicate the positions of the lugs. These indicia 22, tell the person desiring to remove the safety closure 13 from the container 10 where to press radially inwardly on the outer closure member 15 in order to press the lugs 21 into the recesses 20.

The improved safety closure provided by this invention can be efficiently mass produced, because it comprises only two parts each of which can be formed of plastic using conventional molding techniques. Furthermore, the two parts can be easily assembled, because the sidewalls of the outer member 15, as well as the bottom flange 16, are sufficiently flexible that they can be flexed outwardly to permit the entry of the inner closure member 14. Once the inner member 14 is snapped into the outer member 15, the sidewalls and bottom flange of the outer member 15 return to their normal configuration so that the inner member 14 is held captive by means of the closed top wall of the outer member 15 and the bottom flange 16.

While the invention has been described with specific reference to an exemplary embodiment which includes a pair of diametrically opposed lugs on the outer closure member and a corresponding pair of diametrically opposed recesses on the inner closure member, it should be appreciated that the invention is equally applicable to other designs utilizing virtually any desired number of cooperating lugs and recesses. Thus, more than two lugs and recesses may be used, or only a single lug and recess may be used. It should also be recognized that the positions of the lugs and recesses are interchangeable, so that the lugs may be located on the inner closure member and the recesses in the outer closure member, or both lugs and recesses may be provided on both members.

As can be seen from the foregoing detailed description, this invention provides an improved safety closure which requires such a combination of manipulations to remove it that removal of the closure by a child is rendered extremely difficult or even impossible. Since the closure requires simultaneous application of lifting, radially inwardly compressive, and rotational forces to remove it, it requires conscious effort for removal so that accidental removal is virually impossible. Furthermore, the safety closure provided by this invention requires only two parts which can be easily made of molded plastic, so that the entire closure can be economically massed produced from inexpensive plastic materials. Finally, the closure can be easily and quickly assembled.

Claims

I claim as my invention:

1. A safety closure for containers having external threaded openings, said closure comprising the combination of an internally threaded inner closure member adapted to be threaded onto the externally threaded opening of the container to close said opening, said inner closure member and said container being shaped to form an open space directly beneath at least the outer peripheral portion of the bottom of said inner closure member when said member is threaded onto said container, said inner closure member also forming a plurality of recesses in the outer side wall thereof, an outer closure member fitted over said inner member and freely rotatable relative to said inner member to normally prevent rotation of said inner member, the top of said outer member overlapping the top of said inner member and the bottom of said outer member forming a flange extending radially inwardly beyond the outer periphery of the bottom of said inner member in said open space to hold said outer member captive on said inner member, the axial dimension of the internal space between the top of said outer member and said flange being substantially greater than the maximum axial dimension of said inner member to permit limited axial movement of said outer member relative to said inner member, said outer closure member forming a plurality of lugs projecting inwardly from the inner sidewall thereof, said lugs being axially spaced away from the recesses in the outer sidewall of said inner member when said outer member is in its lowermost position where said flange is spaced away from the bottom of said inner member, said lugs also being normally radially spaced away from said recesses at any axial position of said outer member relative to said inner member, said lugs being located for axial alinement with said recesses when said outer member is in its uppermost position where said flange engages the bottom of said member, the sidewalls of said outer closure member being sufficiently flexible to permit said lugs to be pressed into said recesses when alined therewith to provide latching engagement between said inner and outer members whereby said inner member may be rotated to remove the closure from said container.

2. A safety closure as set forth in claim 1 wherein the recesses formed in said inner closure member include at least one pair of diametrically opposed recesses.

3. A safety closure as set forth in claim 1 wherein indicia are provided on the outer sidewall of said outer closure member to indicate the location of said lugs on the inner sidewall thereof.

4. A safety closure as set forth in claim 1 wherein said outer closure member is dimensioned so that said flange engages the top of the container beneath the inner closure member when the top of the outer closure member engages the top of the inner closure member.