GB2108940A - Safety closure - Google Patents

Abstract

In a two-part safety closure comprising an inner closure member 2 and an outer closure member 10 which is freely rotatable on the inner closure member 2 in one relative axial position (left-hand side of Fig. 1) and drives the inner closure member for on-screwing or unscrewing in a second relative axial position (right- hand side of Fig. 1), spaced portions of the outer wall of the inner closure, or of the inner wall of the outer closure member, are of reduced diameter relative to adjacent portions. For example, the surface 18 of the outer closure member or the surface 20 of the inner closure member may be circumferentially undulated. This reduces the possibility of placing the outer closure member in driving contact with the inner closure member by squeezing the outer member at its lower end (B). Bead 12 may also be circumferentially undulated to facilitate assembly of the closure. <IMAGE>

Description

SPECIFICATION Safety closure This invention relates to safey closures.

Various types of safety closure, or childproof closure as they are sometimes known, have been described and produced. Many such closures are of the two-component type. In these, an inner closure member is screw-threadedly attached to the neck of a container, and an outer closure member is captively retained thereon. The inner and outer closure members, both of which are injection moulded from piastics materials, have interengaging means, e.g. cooperating lugs or splines, whereby in one relative axial position of the closure members the outer closure member may be brought into driving engagement with the inner closure member to screw the inner closure member onto a container or to unscrew it therefrom.In another relative axial position of the inner and outer closure members, however, the outer closure member may be rotated on the inner closure member without imparting any driving motion to the inner member. Closures of this type often require downward pressure to be exerted on the outer closure member to bring the interengaging driving means into driving relation.

It is with this type of safety closure, sometimes known as the "push and turn" closure, that the invention is particularly concerned.

By and large, safety closures of this type are effective, i.e. small children and other irresponsible people cannot open them. In a few cases, however, it has been noted that it is possible to remove the two-art closure from the container by gripping the outer closure member so tightly at its lower end that its lower end is deformed into friction engagement with the lower end of the inner closure member, such that rotation of the outer member while tightly squeezing its lower end has the effect of imparting rotation to the inner closure member sufficient to unscrew the latter from the container. It is an object of the present invention to provide a safey or childproof closure of the two-component variety which is not subject to this disadvantage.

According to the present invention a two-part safety closure comprises (i) an inner closure member having a top and a screw-threaded skirt for screw-threaded application to a container, and (ii) an outer closure member rotatable relative to the inner member in a first relative axial position of the closure members and rotatable with the inner members in a second relative axial position of the closure members, said outer closure member having a top and a depending skirt at the lower end of which is on inwardly-directed bead situated beneath the lower end of the skirt of the inner closure member, spaced portions of the outer wall of the inner closure member, or of the inner wall of the outer closure member, above said inwardly directed bead being of reduced diameter relative to adjacent portions thereof.

The reduced diameter portions of the inner or outer closure member preferably take the form of axially-extending undulations formed on the inside wall of the outer closure member or on the outside wall of the inner closure member.

Preferably such undulations are odd in number, in order that the lands between adjacent undulations are not diametrically opposed. Thus, when the lower end of the outer closure member of a closure according to the invention is squeezed tightly, the chances are very much reduced that frictional engagement will occur between the outer and inner closure members.

The precise number of undulations will depend to a large extent on the size of the closure. Suitably there will be between three and eleven such undulations. For a 30mm. diameter cap five undulations are especially suitable.

Preferably, when it is the outer wall of the inner closure member which is undulated the inwardlydirected bead of the outer closure member is complementarily indulated, to assist the easy assembly of the two closure members to each other.

Both closure members are suitably injectionmoulded from plastics materials such as polypropylene and polybutylene.

An embodiment of the present invention is illustrated in the drawings, in which Figure 1 is a diagrammatic sectional elevation of a two-part closure according to the invention, showing the outer and inner closure members in two different relative axial positions; Figure 2 is a section on the line I1--II of Figure 1;and Figure 3 is a section on the line Ill-Ill of Figure 1.

Referring to the drawings, an inner closure member is provided with a screw-thread 4 for threaded engagement with a complementary threaded portion on a container (not shown). A downwardly-depending annular sealing flange 6 is provided on the inside of the top portion of the closure member 2, for sealing engagement with the mouth of the container in known manner (a separately formed and fitted sealing wad may be used instead of the annular flange 6). An outer closure member 10 surrounds the inner closure member 2 and is held captive thereon by virtue of an inwardly-directed bead 12 lying beneath the lower end of the skirt of the inner closure member 2.The inside of the top of the outer closure member 10 is provided with a series of radially directed splines or lugs 14, and the outside of the top portion of the inner closure member 2 is provided with a series of complementary lugs 16.

In the relative position of the two closure members shown on the left hand side of Figure 1, the lugs 14, 1 6 are not in engagement. Thus, rotation of the outer closure member 10 in either direction is possible, unfettered by contact with the inner closure member 2. However, when the outer closure member is pressed downwardly on the inner closure member, as illustrated in the right-hand side of Figure 1, the lugs 14 and 16 are in driving engagement and rotation of the outer closure member is transmitted to the inner closure member to unscrew it from the container.

As mentioned above, in some prior art two-part closures, tightly squeezing the lower end of the outer closure member 10, at "B" as indicated in Figure 1, places the cylindrical surface 18 of the outer closure member into frictional contact with the cylindrical surface 20 of the inner closure member. Unscrewing whilst tightly gripping at "B" enables the two-part closure to be removed from the container.

In accordance with the present invention, however, one of the surfaces 18 and 20 (surface 20 as illustrated) is not truly cylindrical. By virtue of the thickness of the wall of the inner closure member in the region of the surface 20 being reduced at spaced positions, as shown in greater detail in Figure 2, tight gripping of the outer closure member at "B" stands considerably less chance of placing the adjacent surfaces of the two closure members one cylindrical and one undulating, in frictional contact.

Figure 2 shows the configuration of the lower end of the inner closure member 2. The surface 20 is of an undulating nature being made up of spaced depressions or undulations 22, situated between raised lands 24. In the regions of the undulations 22 the diameter of the outer wall of the inner closure member 2 is reduced relative to that in the regions of the lands 24. In the example illustrated, the thickness of the wall at the depressions 22 is approximately 70% of that at the lands 24.

Figure 3 shows in more detail the configuration of the inwardly-directed bead 12 at the lower end of the outer closure member. The outer surface 26 is cylindrical while the inner surface is complementarily-shaped to the surface 20 of the wall 2 of the inner closure member. That is to say, undulations or depressions 28 alternate with lands 30. This makes for easy assembly of the closure members, the snapping of bead 12 over undulated surface 20 being facilitated. It will be appreciated that the undulations 28 and lands 30 of the outer closure member are of smaller diameter than the lands 24 and undulations 22 of the inner closure member respectively, in order that there should always be interference between the bead 12 and the surface 20 of the inner closure member on assembly of the two members together.

When the two-part closure is attached to a container, removal can only be accomplished by pushing the outer member downwards relative to the inner member, so that the two members assume the relative positions shown on the righthand side of Figure 1, and then rotating the outer member in the unscrewing direction. The coacting lugs 14, 16 transmit rotational movement of the outer member to the inner member to permit removal of the closure. It will be seen, however, that tight squeezing of the lower end of the wall of the outer member at position "B", accompanied by rotation of the outer member, will not have the effect of transmitting the rotational movement to the inner member.

One advantage of the two-part closure of the invention is that, if desired, the inner closure member may be used alone, i.e. as a primary closure without the secondary overcap or outer closure member. In order to give the end user this choice, it is of course necessary to supply the two parts of the two-part closure member individually and not pre-assembled. For use as a single closure member, the inner closure member may have a knurled outer wall, to allow for easy gripping, although this knurling should preferably not be placed on those parts of the inner closure member most likely to be gripped by the outer member as it is squeezed in an unauthorised attempt at removal.

Claims (Filed on 12.10.82) 1. A safety closure comprising (i) an inner closure member having a top and a screwthreaded skirt for screw-threaded application to a container, and (ii) an outer closure member rotatable relative to the inner member in a first relative axial position of the closure members and rotatable with the inner member in a second relative axial position of the closure members, said outer closure member having a top and a depending skirt at the lower end of which is an inwardly-directed bead situated beneath the lower end of the skirt of the inner closure member, spaced portions of the outer wall of the inner closure member, or of the inner wall of the outer closure member, above said inwardlydirected bead being of reduced diameter relative to adjacent portions thereof.

2. A safety closure as claimed in claim 1 wherein the reduced diameter portions of the inner or outer closure member take the form of axially-extending undulations formed on the inside wall of the other closure member or on the outside wall of the inner closure member.

3. A safety closure as claimed in claim 1 or 2 wherein there is an odd number of undulations.

4. A safety closure as claimed in claim 3 wherein there are between three and eleven undulations.

5. A safety closure as claimed in any of claims 1 to 4 wherein the outer wall of the inner closure member is undulated and the inwardly-directed bead of the outer closure member is complementadly undulated.

6. A saftey closure as claimed in any of claims 1 to 5 wherein the inner closure member is provided with a knurled outer wall.

7. A safety closure as claimed in claim 1, substantially as described with reference to the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. outer closure member is transmitted to the inner closure member to unscrew it from the container. As mentioned above, in some prior art two-part closures, tightly squeezing the lower end of the outer closure member 10, at "B" as indicated in Figure 1, places the cylindrical surface 18 of the outer closure member into frictional contact with the cylindrical surface 20 of the inner closure member. Unscrewing whilst tightly gripping at "B" enables the two-part closure to be removed from the container. In accordance with the present invention, however, one of the surfaces 18 and 20 (surface 20 as illustrated) is not truly cylindrical. By virtue of the thickness of the wall of the inner closure member in the region of the surface 20 being reduced at spaced positions, as shown in greater detail in Figure 2, tight gripping of the outer closure member at "B" stands considerably less chance of placing the adjacent surfaces of the two closure members one cylindrical and one undulating, in frictional contact. Figure 2 shows the configuration of the lower end of the inner closure member 2. The surface 20 is of an undulating nature being made up of spaced depressions or undulations 22, situated between raised lands 24. In the regions of the undulations 22 the diameter of the outer wall of the inner closure member 2 is reduced relative to that in the regions of the lands 24. In the example illustrated, the thickness of the wall at the depressions 22 is approximately 70% of that at the lands 24. Figure 3 shows in more detail the configuration of the inwardly-directed bead 12 at the lower end of the outer closure member. The outer surface 26 is cylindrical while the inner surface is complementarily-shaped to the surface 20 of the wall 2 of the inner closure member. That is to say, undulations or depressions 28 alternate with lands 30. This makes for easy assembly of the closure members, the snapping of bead 12 over undulated surface 20 being facilitated. It will be appreciated that the undulations 28 and lands 30 of the outer closure member are of smaller diameter than the lands 24 and undulations 22 of the inner closure member respectively, in order that there should always be interference between the bead 12 and the surface 20 of the inner closure member on assembly of the two members together. When the two-part closure is attached to a container, removal can only be accomplished by pushing the outer member downwards relative to the inner member, so that the two members assume the relative positions shown on the righthand side of Figure 1, and then rotating the outer member in the unscrewing direction. The coacting lugs 14, 16 transmit rotational movement of the outer member to the inner member to permit removal of the closure. It will be seen, however, that tight squeezing of the lower end of the wall of the outer member at position "B", accompanied by rotation of the outer member, will not have the effect of transmitting the rotational movement to the inner member. One advantage of the two-part closure of the invention is that, if desired, the inner closure member may be used alone, i.e. as a primary closure without the secondary overcap or outer closure member. In order to give the end user this choice, it is of course necessary to supply the two parts of the two-part closure member individually and not pre-assembled. For use as a single closure member, the inner closure member may have a knurled outer wall, to allow for easy gripping, although this knurling should preferably not be placed on those parts of the inner closure member most likely to be gripped by the outer member as it is squeezed in an unauthorised attempt at removal. Claims (Filed on 12.10.82)

1. A safety closure comprising (i) an inner closure member having a top and a screwthreaded skirt for screw-threaded application to a container, and (ii) an outer closure member rotatable relative to the inner member in a first relative axial position of the closure members and rotatable with the inner member in a second relative axial position of the closure members, said outer closure member having a top and a depending skirt at the lower end of which is an inwardly-directed bead situated beneath the lower end of the skirt of the inner closure member, spaced portions of the outer wall of the inner closure member, or of the inner wall of the outer closure member, above said inwardlydirected bead being of reduced diameter relative to adjacent portions thereof.

2. A safety closure as claimed in claim 1 wherein the reduced diameter portions of the inner or outer closure member take the form of axially-extending undulations formed on the inside wall of the other closure member or on the outside wall of the inner closure member.

3. A safety closure as claimed in claim 1 or 2 wherein there is an odd number of undulations.

4. A safety closure as claimed in claim 3 wherein there are between three and eleven undulations.

5. A safety closure as claimed in any of claims 1 to 4 wherein the outer wall of the inner closure member is undulated and the inwardly-directed bead of the outer closure member is complementadly undulated.

6. A saftey closure as claimed in any of claims 1 to 5 wherein the inner closure member is provided with a knurled outer wall.

7. A safety closure as claimed in claim 1, substantially as described with reference to the drawings.