This invention relates to improvements in safety caps. More particularly it is concerned with container caps having an inner closure member which removably seals the mouth of a container and a cowling which fits over this closure member.

With these caps the cowling is normally fitted over the closure member in such a way that it may be depressed from a first position (wherein it is freely rotatable relative to the closure member) to a second position in which it engages this member. A biasing mechanism may also be provided which urges the cowling to its disengaged position. The nature of these mechanisms is normally such that the force required to initially depress the cowling is greater than that necessary to subsequently maintain the engagement. If the cap once fitted to a container is to be removed the outer cowling must therefore be first pushed downwardly to engage the closure member and then subsequently rotated while being, held in this depressed position. It is this multiplicity of operations which serves to prevent the cap being removed by young children.

In order to disclose any unauthorized tampering or opening of the container ^' it is also known to mould frangible rings onto the base of bottle caps. These rings grip the container neck and thus form a seal which breaks when the cap is unscrewed or otherwise removed. This arrangement however suffers from the disadvantage that the neck of the container has to be specially designed to provide a ridge or other

protrusion capable of engaging the security ring.

It is therefore an object of this invention to ameliorate the aforementioned disadvantage and accordingly this invention discloses a safety cap which includes an inner closure member adapted to removably seal the mouth of a container, a cowling fitted over the closure member in such a manner as to be movable between a first position wherein it is freely rotatable in at least one direction and a second depressed position wherein it engages said closure member so that subsequent rotation of the cowling serves to remove said closure member, and a biasing mechanism which is adapted to urge the cowling to said first position; wherein the closure member includes a projection which is disposed below a frangible panel or membrane in the cowling so that when said cowling is depressed to said second position to initially remove the cap from the container said panel or membrane is displaced and/or broken.

One preferred embodiment of this invention will now be described with reference to the attached drawings in which:

Figure 1 shows a perspective view from the top of a safety cap according to this invention,

Figure 2 shows a perspective view of this safety cap from the bottom,

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Figure 4 shows a cross-sectional view of the cap along the lines A-A of figure 3

Figure 5 shows a cross-sectional view of the cap along the lines B-B of figure 2, and

Figures 6 and 7 show detailed views of part of engagement mechanism between the closure member and cowling.

The cap is indicated generally by the numeral 1 and comprises an outer cowling 2 and closure member 3 which fits within the cowling. Threads 4 are also formed within the closure member to enable it to be screwed onto a medicine bottle or the like and circumferential lips 4A are provided to seal against the mouth of the bottle. The diameter of the closure member as shown in figure 2 is slightly less than the interior dimensions of the cowling 2 so that one is able to rotate with respect to the other. In order to retain the closure member in place however there is a flange 4B around the inside rim of the cowling. With this embodiment a plastics material is used for the cap which is sufficiently resilient that these flanges deform to allow the closure member to be push- fitted into the cowling during its initial assembly.

A set of bevelled lugs 5 and 6 are formed on the facing circumferential surfaces of the closure member and cowling as shown in figures 4 and 5 to ensure that the cowling is

able to rotate freely in only one direction with respect to the closure member. Any rotation of the cowling in the direction of arrow "A" is transmitted directly to the closure member when these lugs engage as illustrated.

Arranged around the upper periphery of the closure member and the adjacent interior of the cowling are sets of square teeth 7 and 8. Although these teeth are shown as being disengaged in figure 4 they are nevertheless adapted to _. interfit (see figure 6) when the cowling is depressed downwardly onto the closure member as described hereunder.

To bias the closure member and cowling to their disengaged position a spring mechanism is provided which comprises a tapered boss 9 extending centrally up from the top of the closure member and a cylindrical ring 10 which is formed immediately above the boss 9 on the interior surface of the cowling. The lower edges 10A of this ring may bear against the inclined portion 11 of base 11A of the boss to prevent the teeth 7 and 8 from engaging and thus allow the cowling and closure member to rotate in at least one direction relative to one another as mentioned earlier.

There may be a plurality.of slots 11B in the ring 10 (see figure 4) and in such case the lower edges 10A of the ring are adapted to resiliently deform outwardly over the boss 9 so that the cowling can be depressed down onto the closure member to engage the teeth 7 and 8. Upon release of the cowling the ring would again return to-its undeformed configuration whereby the■—■———■

teeth 7 and 8 are disengaged.

With the illustrated embodiment however the most significant biasing effect is provided by tapering the upper wall 12 of the cowling towards its center as shown in figure 4. This construction enables the wall 12 to resiliently deform upwardly as the cowling is pressed down onto the closure member and the shoulder 13 engages said wall.

In accordance with this invention a panel 14 is moulded into the upper wall 12 of the cowling immediately above the boss 9. This panel may itself be rupturable or alterna¬ tively it may be joined to the wall 12 by frangible ribs 15. -The boss 9 has a stepped configuration as best shown in figure 4 with the lower inclined portion 11 being separated from an upper cylindrical portion 16 by the shoulder 13. This cylindrical portion 16 is in axial alignment with the panel 14 and is preferably of about the same diameter.

In use the cap can be easily screwed onto the mouth of a container by grasping the kuurled sides 17 of the cowling and rotating it in the direction shown by arrow "A". As mentioned earlier such rotation by virtue of lugs 5 and 6 is transmitted directly to the closure member without any additional manipulation or force needing to be applied to the cap. Once the cap is tightened onto the bottle however simple reverse rotation of the cowling will not remove it

as the inclined configuration of these lugs 5 and 6 allows it to turn freely without engaging the closure member. To remove the cap it is then necessary to first depress the cowling onto the closure member until the shoulder 13 abuts the lower surface of wall 12 so as to overcome the biasing mechanisms described earlier and engage the teeth 7 and 8. With these teeth engaged the cowling and closure member are locked together and the cap can be unscrewed from the container. With the initial removal of the cap however this depression of the cowling onto the upper portion 16 of boss 9 serves to displace panel 14 and break the ribs 15. Any unauthorized tampering or removal of the cap (say for example before the point of sale) thus becomes readily apparent upon even a cursory inspection. In order to further enhance the visability of a broken seal the top of the boss may also be coloured red or other bright hue to provide a high contrast to the surrounding cowling surface once the panel 13 is displaced. Preferably the height of the cylindrical portion 16 is also sufficient to protrude above the upper wall of the cowling 12 and be readily visible from the side once the panel is broken.

It will thus be appreciated that this invention at least in the form of the embodiment described provides a novel and unique improvement in safety caps. Clearly however the particular example disclosed is only the currently preferred form of this invention and a wide variety of modifications may be made which would be apparent to a man skilled in the art. For example the invention is not limited to any

specific material for its construction. Further, while it is currently proposed to incorporate a displacable panel in the cowling any other mechanically equivalent arrangement such as a rupturable membrane may also be used..