Patent Description:
Child resistant safety closures comprising two nested closure members are well known. Typically, outer and inner cap members are provided with cooperating sets of lugs which engage each other when the outer closure is rotated in the direction to remove the closure from a container. A plurality of spring fingers on the inner surface of a top panel of the outer closure member urge the outer closure member away from the inner closure member and prevent engagement of the lugs. The outer surface of the top panel of the inner closure member is formed with ramps which are associated with the outer cap member spring fingers so that when the outer cap member is rotated relative to the inner cap member in a direction to apply the closure to a container the spring fingers engage the ramps to cause the cap members to rotate together. When the outer cap member is rotated in the opposite, or unscrewing, direction the spring fingers ride over the ramps to prevent accidental or unwanted removal of the closure. Only when the closure is rotated in the unscrewing direction and an axial force is simultaneously applied to the outer closure member the cooperating lugs are interengaged to unthread the inner closure member from the container. One such closure is disclosed in <CIT> which accords with the preamble of claim <NUM>.

The present invention seeks to provide improvements in or relating to such closures.

According to a first aspect of the present invention there is provided a child-resistant closure for a container as claimed in claim <NUM>.

The rib formed integrally with an inner cap drive formation may allow for light-weighting of the drive formation by removing material.

The rib may extend along substantially the entire length of the skirt of the inner cap.

Each drive formation of the inner cap may have a respective rib.

According to a second aspect there is provided a closure according to the first aspect in combination with a container.

Further particular and preferred aspects of the present invention are set out in the accompanying claims, features of which may be combined in combinations other than those explicitly disclosed without departing from the scope of the invention as defined by the appended claims.

The present invention will now be more particularly described with reference to, and as shown in, the accompanying drawings, in which:.

In <FIG> a closure is shown generally indicated <NUM>. The closure <NUM> is made up of two components: an outer cap <NUM>, shown in <FIG> an inner cap <NUM>, shown in <FIG>.

The outer cap <NUM> is formed with a circular top panel <NUM> integrally moulded with a depending cylindrical skirt <NUM>. Formed on the underside of the top panel <NUM> and extending into the interior of the outer cap <NUM> are a plurality of finger-like spring members <NUM>.

The embodiment illustrated shows six spring members <NUM>, but as few as one or two members may operate satisfactorily, and more than six members may be employed if desired. The spring members <NUM> take the form of inclined tabs integrally formed with the underside of the top panel <NUM>. The spring members <NUM> are inclined at an angle of about <NUM> degrees with respect to the vertical axis of the outer member <NUM>; however, the angle of inclination may be varied as long as a ratcheting function, to be described later, can be properly performed. It will also be noted that the spring members <NUM> are positioned radially inwards of the periphery of the panel <NUM>. The fingers are curved along their length with generally the same radius of curvature as the sidewall <NUM>.

In addition to the spring members <NUM>, a plurality of drive lugs <NUM> are also moulded into the underside of the top panel <NUM> and depend downwardly. The drive lugs <NUM> are located adjacent to the extreme outer portion of the inside diameter of the outer cap <NUM> adjacent the depending skirt <NUM>. The drive lugs <NUM> then extend inwardly toward the springs <NUM> but their edges terminate before reaching the spring members <NUM>. The illustration of five drive lugs <NUM> is by way of example and a single drive lug would function properly; but multiple drive lugs are preferred to allow a number of different removal engagement positions.

On the outer surface of the side skirt <NUM> a plurality of assembly ribs <NUM> are provided. The ribs <NUM> extend axially along the skirt and project outwardly therefrom. There are six ribs <NUM>, each one being associated with a respective drive projection <NUM>.

In this embodiment the ribs <NUM> extend along substantially the full height of the skirt <NUM>. The ribs <NUM> also extend into and merge with the drive projections <NUM>, each connecting to the leading edge (i.e. the edge which is used to provide drive in use) of a respective castellated drive lug. The ribs <NUM> allow for the venting of pressure build up as the inner and outer caps are assembled together (see below for further details). In addition, the ribs provide additional strength to support the edge of the drive lug used for engagement when unscrewing the closure. This additional strength allows, in this embodiment, for a thinning of the drive projections in non-functioning areas. Accordingly the projections have a very generally shallow U-shape configuration.

A retention bead <NUM> is moulded into the interior wall of the depending skirt <NUM> near the open end of the depending skirt <NUM>. The bead <NUM> is continuous about the entire circumference of the depending skirt <NUM>.

The outer cap <NUM> may be manufactured of any material sufficiently resilient to provide the necessary spring quality for the integrally moulded spring members <NUM>, for example polyethylene and propylene.

The inner cap <NUM> is also formed as an integral unit having a circular top panel <NUM> and a depending skirt <NUM> attached thereto.

The interior of the depending skirt <NUM> is provided with a screw thread <NUM> for engagement with a threaded neck finish of a container.

The upper portion of the inner cap member <NUM> is of a general configuration that may be considered to be castellated. A ring wall <NUM> rises above the plane of the top panel <NUM>.

Spaced at intervals around the ring wall <NUM> are upwardly or axially extending castellation-like drive projections <NUM>. In the assembled closure, the drive lugs <NUM> on the interior of the outer cap <NUM> are sized such that they may mesh into the openings between the drive projections <NUM>. This imparts a driving force to the inner cap member <NUM> so that it may be driven by the outer cap <NUM>.

A retention bead <NUM> is moulded into the exterior surface of the depending skirt <NUM>. The retention bead <NUM> extends about the entire circumference of the depending skirt <NUM> and is of a diameter greater than that of the retention bead <NUM> formed in the depending skirt <NUM> of the outer cap <NUM>.

Referring also to <FIG>, projecting vertically up from and formed integrally with the top panel <NUM> are a plurality of ratchet lug means. In the embodiment shown the ratchet lug means take the form of six ramp-type lugs <NUM>. Each of the ramp lugs <NUM> has a substantially L-shaped configuration formed by an inclined ramp portion <NUM> joined to a radially extending, axially projecting vertical wall portion <NUM>. The beginning of the ramp portion is in a plane substantially identical to the plane of the top panel <NUM>. The vertical wall portion <NUM> terminates with an abutment face 31a and is at an elevation such that the spring members <NUM> will jam on the face 31a if it is attempted to pass them by the vertical wall portion <NUM>. The wall portion <NUM> extends radially inwards from the ring wall <NUM>, approximately from the middle of the drive projection <NUM>.

The ramp portion <NUM> is shaped and profiled so as to be sympathetic to the trajectory of the spring fingers as they pass over in use. The portion has a variable section sweep with a section that varies as the ramp height increases i.e. the ramp face is not flat. The trajectory of the portion has a constant radius; the section that sweeps along the radius is constantly changing (in both X and Y planes). This allows the spring finger to be in maximum contact with the ramp through rotation so that there is no time at which there is only a point contact between them.

This allows for a ramp to be formed with the minimum amount of material whilst providing maximum contact with the finger during rotation.

Spaced between each of the ramp lugs <NUM> are hump-like, arcuately extending detent projections <NUM>. The detent projections <NUM> project above the plane of the top panel <NUM> and lie in the path of travel of the spring members <NUM> in use. As discussed further below, the projections <NUM> hold the spring members <NUM> in place during application of the closure to transmit the force directly to the ramp face 31a and help stop the finger deforming back on itself. The profile of the front section 32a of the projections is selected to match the corresponding shape of the part of the spring members which lie over them in use (see <FIG>) so that the support they provide is maximised. The sides 32b, 32c of the projections are flat and arcuate and generally match the curvature of the sides of the ramp <NUM>.

The inner cap <NUM> is an independent closure in itself for a container. The inner <NUM> therefore may be made of any suitable material and need not necessarily be made of the same material as that of the outer cap <NUM>; a thermoplastic material such as polyethylene or polypropylene may, for example, be used.

The closure <NUM> is formed by assembling the outer cap <NUM> and the inner cap <NUM>. To assemble the completed closure, the retention bead <NUM> is forced over the retention bead <NUM>, in the process causing the depending skirt <NUM> of the outer closure cap member <NUM> to spring outwardly slightly. Once the retention bead <NUM> has passed over the larger diameter retention bead <NUM>, the depending skirt <NUM> springs back inwardly trapping the inner cap <NUM> within the outer cap <NUM>. The fit between the outer cap <NUM> and the inner cap <NUM> is not tight. There is an appreciable gap between the interior of the depending skirt <NUM> and the exterior of the depending skirt <NUM>. Thus, the outer cap <NUM> may both rotate and axially slide with respect to the inner cap <NUM>.

In use the inner cap <NUM> is threadably engaged on an exteriorly threaded finish of a container. A sealing disk (not shown) may be provided in the inner cap <NUM> and will be trapped between the upper portion of the finish and the lower portion of the top panel of the inner cap <NUM>.

When the outer cap <NUM> is rotated clockwise the spring members <NUM> are moved so as to become in driving engagement with respective faces 31a as shown in <FIG>. Thus, the completed closure may be screwed onto the finish of a container, since the rotation of the outer cap <NUM> will cause the spring members <NUM> to drivingly engage the ratchet lugs <NUM> and consequently turn the outer cap <NUM> and the inner cap <NUM> as a unit in the tightening direction.

In the tightening direction, the spring members <NUM> wedge between the ramps <NUM> and the projections <NUM>.

Conversely, as illustrated in <FIG> it may be seen that if the outer cap <NUM> is rotated in the opposite direction or the direction normally unscrewing the cap from the container, the springs <NUM> slip over the ratchet lugs <NUM>. The profile of the ramp <NUM> changes constantly as the ramp height increases. This allows for maximum support to be provided to the spring fingers <NUM>.

Thus, these two functions provide a one-way ratchet drive for the inner cap <NUM>. The outer cap <NUM> thus can rotate freely with respect to the inner cap <NUM> in the unscrewing direction. It is this feature which makes the closure child-resistant, since it is impossible to unscrew the combined closure without an additional motion.

The detent projections <NUM> act as a further safety feature. If the outer cap <NUM> is turned in a direction which would normally unscrew the combined closure from the finish, once the springs <NUM> have risen completely up the ramp portion <NUM> of the ramp lugs <NUM> and fallen off the opposite side, the detent projections <NUM> will tend to hold the springs <NUM> in that position. It is necessary then to exert further force to move the leaf springs <NUM> to the next ramp to raise it up the ramp portion <NUM>. In addition, the detent projections <NUM> are positioned such that the drive lugs <NUM> are aligned with the drive projections <NUM> when the springs <NUM> are stopped by the detent projections <NUM>. This position helps prevent overstressing of the springs <NUM> when the closure is subjected to a vertical load, as in a warehouse. The drive lugs <NUM> are in contact with the drive projections <NUM> to prevent this overstressing.

In this embodiment the ramps <NUM> and projections <NUM> are shaped and profiled so that they support the edge/tip of the spring finger during substantially the entire time it is in contact with these features.

To remove the closure from a container finish, the outer cap <NUM> must be compressed downwardly over the inner cap <NUM>.

The spring members <NUM> serve to normally keep the outer cap <NUM> and the inner cap <NUM> in their axially spaced relationship, in which removal of the closure from the container is impossible. However, utilising the spring function of the springs <NUM>, the outer cap <NUM> may be pressed downwardly over the inner cap <NUM>. The downward displacement of the outer cap <NUM> brings the drive lugs <NUM> into engagement with the spaces between the drive projections <NUM>.

Alignment of the drive lugs <NUM> and the spaces between the drive projections <NUM> may not be perfect at the time the outer cap <NUM> is pressed downwardly. However, slight rotation of the outer cap <NUM> in the loosening direction will bring these members into proper drive engagement. With the drive lugs <NUM> properly engaged, the outer cap <NUM> may be rotated and the inner cap <NUM> will rotate with it as a unit through this driving engagement.

Once the combined closure is removed from the container and the downward pressure on the outer cap <NUM> is released, the combined closure will spring back under the influence of the spring member <NUM>, thereby placing the closure in configuration suitable for reapplication. The user may then screw the closure back onto the container finish utilising the driving engagement of the springs <NUM> and the ratchet lugs <NUM>.

Once back on the container, the combined closure may not be removed again without the downward compression of the outer cap <NUM> over the inner cap <NUM>. When a child attempts to remove the assembled closure from a container without pressing downwardly on the outer cap <NUM>, an audible warning sound is produced. The springs <NUM> slipping over the ratchet lugs <NUM> and hitting the top panel <NUM> produces a loud and distinctive "clicking" sound. This sound may be heard for some distance and can serve as a warning to parents that children are tampering with a container whose contents may be harmful to them.

The closure of this invention assembled from the outer cap <NUM> and the inner cap <NUM> may be applied by conventional capping machinery, since there is no need for any manipulation of the closure during the tightening procedure.

In <FIG> the interior of an outer cap <NUM> formed according to an alternative embodiment is shown. The cap <NUM> is very similar to the cap <NUM>. The curved spring members <NUM> and the U-shape drive lugs <NUM> can clearly be seen.

In <FIG> a plan view of an inner cap <NUM> for use in conjunction with the outer cap <NUM> is shown.

In <FIG> an underplan view of the inner cap <NUM> is shown. The inner cap has been fitted with a disc-shape seal <NUM> which in this embodiment is attached to the underside of the top panel <NUM> so that it can seal against the rim of a container neck in use.

Claim 1:
A child-resistant closure (<NUM>) for a container, the child-resistant closure (<NUM>) comprising outer and inner nested caps (<NUM>, <NUM>) each having a top panel (<NUM>, <NUM>) and a side skirt (<NUM>, <NUM>) depending generally peripherally therefrom, said outer cap (<NUM>) loosely generally encompassing said inner cap (<NUM>) to allow relative rotary and axial movement there between, the outer and inner caps (<NUM>, <NUM>) having corresponding drive formations (<NUM>, <NUM>) which can be brought into driving engagement when the outer and inner caps (<NUM>, <NUM>) are moved axially towards one another to a first axial position, one of the inner and outer caps (<NUM>, <NUM>) comprising one or more spring members (<NUM>) for urging the inner and outer caps (<NUM>, <NUM>) axially away from each other to a second axial position, the other of the inner and outer caps (<NUM>, <NUM>) comprising one or more ramps (<NUM>), the one or more spring members (<NUM>) providing a biasing force to maintain the outer and inner caps (<NUM>, <NUM>) in the second axial position and drivingly engaging one or more ramps (<NUM>) in the second axial position so as to drive the outer and inner caps (<NUM>, <NUM>) together in a screwing direction, but slipping over the one or more ramps freely in an unscrewing direction, downward pressure on the outer cap (<NUM>) overcoming the spring member bias to move the outer and inner caps (<NUM>, <NUM>) to the first axial position to allow unscrewing of the child-resistant closure (<NUM>) using the drive formations (<NUM>, <NUM>), characterised in that:
the external surface of the inner cap (<NUM>) side skirt (<NUM>) includes one or more axial ribs (<NUM>) for allowing venting when the outer and inner caps (<NUM>, <NUM>) are initially assembled together,
the or each axial rib (<NUM>) is formed integrally with a drive formation (<NUM>) of the inner cap (<NUM>) to strengthen the said drive formation (<NUM>), and
the or each axial rib (<NUM>) connects to an edge of the said drive formation (<NUM>) of the inner cap (<NUM>) which, in use, engages drivingly with a corresponding drive formation (<NUM>) of the outer cap (<NUM>).