Safety Closures

Abstract

A safety closure with an outer ring mounted over the threaded cap for a bottle with an annulus extending in from the outer ring engageable in a groove on the outer surface of the cap and with a clutch engagement between the annulus and the side of the groove at one limit and preferably the upper limit of axial movement between the ring and the cap.

Description

This invention relates to safety closure means and/or methods of manufacturing said safety closure means.

Safety closures for containers are known but as yet are not in general use. We believe that the complexity of construction and assembly of known safety closures results in excessive and impractical manufacturing costs. Also the more complex the engineering the more likely there is to be some failure during the life of the safety closure. Finally, many closures are so difficult to manipulate that even an adult user may have trouble in gaining access to the container.

It is therefore an object of the present invention to provide a safety closure and/or methods of manufacturing said safety closure which will substantially reduce the above-mentioned disadvantages or at least provide a useful choice over safety closures already known.

Accordingly in one aspect the invention may broadly be said to consist in a safety closure for containers having a neck threaded internally or externally said closure means comprising an inner cap- or cup-shaped part adapted to screw on or into the neck of said container and an outer ring-shaped part mounted on said inner part, said inner and outer parts being capable of limited relative axial movement and rotationally being free from each other except when deliberately moved to the limit of relative axial movement, such movement in one direction causing the engagement of a clutch comprising in turn a component on the inner part and a component on the outer part, said components being adapted to rotate together as to cause a rotary unscrewing motion imparted to the ring, to be transmitted to the cap when the two caps are moved to one axial limit and are held firmly at the limit of movement.

One preferred form of the invention and modifications thereof will now be described with reference to the accompanying drawings in which

FIG. 1 is a cross section of the outer part of the first embodiment of a safety closure according to the present invention.

FIG. 2 is a side elevation of the inner part according to said first embodiment.

FIG. 3 is a cross section through the outer part of a second embodiment of the safety closure.

FIG. 4 is a side elevation of the inner part according to the second embodiment.

FIG. 5 shows the two parts of FIGS. 3 and 4 assembled.

FIG. 6 is a perspective exploded view of the parts of FIGS. 3 and 4, and

FIG. 7 is a side view partly cut away of the closure means fitted to a bottle.

In one preferred form of the invention shown in FIGS. 1 and 2 the safety closure means consists of an inner part formed as a cup or cap 1 adapted to screw over or into the neck of a container and surrounding the inner part 1, an outer part 2 consisting of a ring or hollow cylinder without ends. The outer part has, projecting inwards from its inner surface an annulus or ridge 3. This ridge 3 fits within a wide groove 4 on the outer cylindrical surface of the inner part. The inner diameter of the ridge 3 is less than the diameter of the groove but greater than the diameter of the annuli or ridges 5 and 6 which bound the groove 4. The axial length of the ridge is considerably less than that of the groove. The ring 2 is thus free to rotate on the cup 1 and to move a limited distance axially relative to it but cannot be removed from it without using destructive force.

The outer ring 2 and the inner part or cap 1 are so proportioned that whatever the position of the ring it completely covers the cylindrical surface of the cap and only the ring can be grasped by the hand.

When the safety closure is assembled the cap can be removed from the bottle only by using the ring 2 to unscrew it. For this purpose a clutch is formed by co-operation between the ridge 3 projecting inwards from the ring 2 and the upper ridge 5 bounding the groove 4 of the cap. The clutch is a modified form of dog clutch. The mating surfaces of the two ridges which co-operate to form the clutch are formed into abutments each extending over a quarter of a circumference. When the abutments are interlocked the clutch is engaged and the sleeve will drive the cap so as to unscrew it. Otherwise the sleeve rotates freely.

The clutch cannot easily be engaged accidentally. The faces 7 and 8 are not parallel to the axis of the neck of the bottle but are sloped at an angle, for example an angle of 20.degree. - 55.degree. so that the rotation of the sleeve will not maintain engagement of the clutch unless the two parts are held firmly together, that is, the inclined surfaces tend to disengage the clutch unless a substantial force is exerted by the user moving the inclined faces into engagement.

The unscrewing clutch is provided at the upper axial limit of movement allowed between the ridge 3 and groove 4 and this, while being a comparatively simple manipulation by an adult, is an unnatural movement for a person intending to unscrew the safety closure thereby minimizing the risk of any child gaining access to the contents of a bottle using the safety closure according to the present invention.

In the preferred embodiment of the invention the outer corner 9 of the abutment 7 is rounded, further assisting in the disengagement between the two faces unless the positive upward force is exerted. Also the surface 10 is sloped back at an acute angle as illustrated in FIG. 2 while the surface from the top of the abutment face 8 is at right angles to the axis of the safety closure. This provides a ratchet action and further assists in a tendency to disengage the abutment faces 8 and 9 unless the upward force is exerted.

Accordingly the co-operative surfaces 7 and 8 of the clutch between the cap 1 and the sleeve 2 form a species of ratchet which will freewheel readily except when the sleeve is held firmly up against the upper ridge 5 and is rotated so as to unscrew the cap.

It will be understood that the ratchet means hereinbefore described in which the working faces are so inclined as to facilitate disengagement may be embodied in forms other than the peripheral ridges herebefore described in the preferred embodiment.

The upper surface 11 of the ridge 3 is chamfered or inclined at an angle of approximately 45.degree. from the inner surface of the outer ridge 3. A complementary chamfered portion 12 is provided on the lower surface of the ridge 6. The components are arranged so that there is an interference fit between the ridge 3 and the ridges 5 and 6. Tolerance of fit between the two members is arranged so that when the members are hot and an axial force is exerted the ridge 6 may be forced past the ridge 3 leaving the ridge engaged in the groove between the ridges 5 and 6 for the closure to operate as above described. In the preferred embodiment the two parts of the closure means are moulded from a suitable plastics which may be different for the two parts so that the relative co-effients of expansion will assist with the engagement as outlined above.

The two components would be manufactured separately and would be assembled as above described, for example while the components were still hot after release from the mold. Alternatively the components could be heated and assembled again as above described.

In another preferred form of the invention as illustrated in the FIGS. 3 to 7 the safety closure cap comprising the inner cup or cap 1 and outer ring 2 is again provided with a similar arrangement for engagement and with the unscrewing clutch means as previously described. In this embodiment reference numerals similar to those used in connection with the same components in the embodiment described with reference to FIGS. 1 and 2 are again used.

In this embodiment a second clutch is provided to allow the outer ring to be engaged to screw the cap firmly back on to the bottle. In this instance the clutch is provided between the lower face of the ridge 3 and the upper face of the ridge 6. As it is not objectionable that accidental rotation of the sleeve should tighten the cap, the design of the faces that co-operate for tightening is such that engagement is not discouraged. At each quarter of the circumference there is a step 13 in the ridge 6 of the cap and a step 14 in the ridge 3 of the sleeve. The plane of these steps is parallel to the axis of the parts so that they engage firmly with little axial pressure. Engagement is encouraged by sloping the surface 15 from the head of one step to the foot of the previous abutting face. Thus ratchet action is provided both on the ridge 3 and ridge 6 and ensures as far as possible that little torque will be transferred to the cap 1 to unscrew the cap even when an axial force is exerted tending to engage the second clutch. The second embodiment of the invention is assembled in a similar way to that previously described with the first embodiment.

If a child has access to a bottle with a safety closure according to the present invention and tries to open it, it will find that by using a normal unscrewing action, neither clutch means will engage to provide a significant force in the direction which would unscrew the cap. Even if the child performs the natural act of pressing the two parts together and unscrewing, the ratchet between the lower clutch means will allow the ring to freewheel.

The cap can be removed only by the rather difficult process of raising the ring relative to the bottle and maintaining a firm upward axial pressure while unscrewing the cap 1. The sophistication needed for this sequence of operation is such that a bottle closed by a safety closure according to the present invention will obviate or minimize the likelihood of the cap being removed by a child.

Claims

What is claimed is:

1. A safety closure for a container having a neck including a threaded portion, closure means comprising an inner cap or cup-shaped part to screw relative to the neck of said container, and an outer ring-shaped part mounted on said inner part, clutch means comprising a component on said inner and outer parts, said inner and outer parts including means limiting relative axial movement and rotationally being free from each other except when deliberately moved to the limit of relative axial movement, such movement in one direction causing the engagement of said clutch means, said clutch means components being engageable to rotate together to cause a rotary unscrewing motion imparted to the outer part to be transmitted to the inner part when the two parts are moved to one axial limit and are held firmly at the limit of movement.

2. A safety closure as claimed in claim 1 wherein said clutch means comprises buttresses on said outer part and said inner part respectively, said buttresses having working faces so inclined to the axial direction as to permit the two parts to slip out of engagement unless they are held firmly together.

3. A safety closure as claimed in claim 2 wherein an annulus is provided extending in from the inner surface of said outer part and an annular groove provided on the outer surface of said inner part with the axial length of said annulus substantially less than that of the groove, and with the clutch means provided between the co-operating faces of the ridge and the side of said groove.

4. Apparatus as claimed in claim 3 wherein said clutch means for imparting an unscrewing motion from said ring to said inner part is provided between the top face of said annulus or ridge on the outer member and the upper or top side of the groove of the inner member, thereby requiring an upward axial movement to engage the clutch.

5. Safety closure as claimed in claim 4 wherein the mating surfaces which co-operate to form the clutch means are formed into a plurality of abutments of co-operating faces which are not parallel to the axis of the neck of the bottle but are sloped at an angle so that rotation of the sleeve will disengage the clutch unless the two parts are held firmly together.

6. Safety closure as claimed in claim 5 wherein the outer corner of the abutment face is rounded, further assisting in disengagement between the two members unless the axial engagement force is retained.

7. A safety closure for containers having a neck including a threaded portion, closure means comprising an inner cap or cup-shaped part to screw relative to the neck of said container, and an outer ring-shaped part mounted on said inner part, said inner and outer parts including means limiting relative axial movement and rotationally being free from each other except when deliberately moved to the limit of relative axial movement, such movement in one direction causing engagement of a first clutch comprising buttresses on said outer part and buttresses on said inner part engageable together to cause a rotary unscrewing motion imparted to the outer part to be transmitted to the inner part when the two parts move to the upper axial limit and are held firmly at the limit of the movement, and a second clutch comprising buttresses on said outer part and buttresses on said inner part engageable together to cause a rotary screwing motion imparted to the outer part to be transmitted to the inner part when the two parts move to the lower axial limit but with ratchet means between said buttresses to prevent any engagement of the second clutch tending to unscrew the inner part.

8. Safety closure as claimed in claim 7 wherein the abutment faces or steps in the second clutch are parallel to the axes of the respective parts so that engagement will take place with little axial pressure being inserted by the user.

9. Safety closure as claimed in claim 8 wherein the surfaces between the outermost point of the abutments are inclined to the foot of the next abutment thereby providing a ratchet which will disengage the second clutch upon a movement tending to unscrew the cap.

10. A safety closure for container having a threaded neck, said closure means comprising an inner cap-shaped part to screw onto the neck of the container, an annular groove provided in the outer surface of the inner cap part, an outer ring-shaped part mounted on said inner part, an annulus extending in from the inner surface of said outer ring part to engage within said annular groove with the axial length of the annulus substantially less than the axial length of the groove and with the ring rotationally free from the inner part except when deliberately moved to the limit of the relative axial movement with the outer part covering the cylindrical surface of the inner part irrespective of the axial position thereof such movement in one direction causing the engagement of a clutch comprising in turn buttresses on the inner part and buttresses on the outer part, said buttresses being engageable to rotate together to cause a rotary unscrewing motion imparted to the outer part to be transmitted to the inner part when the two parts are moved to one axial limit and are held firmly at the limit of movement.

11. A safety closure as claimed in claim 10 wherein an inclined face is provided on the annulus extending in from the outer ring part and a complementary inclined face is provided on an outer rim of the inner part so that engagement between said separately formed inner and outer parts having an interference fit between the rim and the annulus is facilitated.