GB2583948A

GB2583948A - Tamper evident closure

Info

Publication number: GB2583948A
Application number: GB1906825.3A
Authority: GB
Inventors: Fernando Serviuc Pavezi Alex; Miguel De Oliveira Pedro
Original assignee: Greif International Holding BV
Current assignee: Greif International Holding BV
Priority date: 2019-05-15
Filing date: 2019-05-15
Publication date: 2020-11-18
Also published as: EP3969387B1; EP3969387A1; GB201906825D0; WO2020229195A1

Abstract

The application discloses a tamper evident closure 10 comprising inner 30 and outer 20 caps with a tamper evident element 40 that is damaged or marked upon opening of the closure. The inner cap is rotatably connected to a container and the caps can move relative to each other (preferably, rotationally, axially or both). The tamper evident element may be a mark, hologram, RFID, NFC or seal that is ruptured, marked or broken by a cutting implement such as a blade or knife 26. The caps may comprise a ratchet mechanism 52 to engage. The tamper evident element may be visible through the outer cap. There may also be a tamper evident frangible band or strip 50 on the outer cap which may also be connected to the inner cap. Ideally, the tamper evident element is located between the caps.

Description

TAMPER EVIDENT CLOSURE

Field of the Invention

This invention relates to a tamper evident closure for a container.

Acknowledgement The invention is a development of (inter alia) a student project carried out at the Delft University of Technology.

Background

The invention is discussed below with reference to tamper evident closures especially suitable for bottles and jerry cans carrying precious Or hazardous material, but is applicable to any other containers requiring tamper evident closure, ranging from prescription bottles to 200t drums.

IS

In order to ensure the safety of the pub] ic and to prevent pilfering during transportation and storage, containers carrying high value or hazardous products are often sealed with tamper evident or tamper resistant closures. Such closures are also widely used in food and medicine containers to prevent counterfeiting, theft and adulteration. In fact, many manufacturers of food and medicines apply tamper evident closures on the containers carrying their products in order to satisfy FDA, UN and similar regulations.

Whilst tamper resistant closures requiring a specialized removal tool provide protection against unauthorized access, they are only applicable to containers destined for consumers who are already in possession of the specialized removal tool, e.g. regular delivery of precious metal from refineries to catalyst manufacturers. Thus their use is limited.

Tamper evident closures, meanwhile, are anti-theft measures that warn a recipient if the container seal has been compromised, i.e., opening the tamper evident closures causes a noticeable change in the tamper evidencing mechanism. One early example is the "safety button" found on the lids of Mason Jars where a negative pressure in the container reduces a convex clickable "bubble" on the lid to a flat or concave immovable surface. Unscrewing the lid breaks the vacuum seal and restores the convex profile on the lid. However such safety buttons can be circumvented as a vacuum may be reintroduced in the Mason Jar by subjecting the jar to a heat cycle, i.e. condensing vapour during cooling creates a vacuum and restores a concave profile in the lid.

Other examples of tamper evident closures include tamper evident bands commonly found on the caps of soft drink and medicine bottles. The tamper evident band is connected to the cap along a line of weakness while engaged with the bottle. Unscrewing the cap will break the line of weakness and irreversibly separates the cap from the tamper evident band.

However tamper evident bands can still be circumvented, since a damaged band or seal can be directly replaced with a counterfeited tamper evident closure. Closures which provide multiple levels of tamper protection/indication and which are difficult and/or expensive to copy are therefore desirable.

Is US5265744 (Duty et al.) teaches a tamper evident childproof cap where a capsule containing a dye is sandwiched between an inner cap and outer cap. In order to unscrew the cap a downward force is applied, in the process rupturing the capsule. However the capsule may rupture accidentally for various reasons, such as physical impact, influence of external temperature and relative humidity on capsule strength and physical state of the dye, e.g., the capsule wall may become brittle when stored in a freezer, or a water based dye may experience significant thermal expansion during freezing or under direct sunlight. Furthermore, the dye must be of food grade and have sufficient longevity if it is intended to be used on containers carrying food and medicines.

US4792053 (Towns et al.) teaches a tamper evident closure with a transparent cap for observing the condition of a telltale sealing sheet secured across the mouth of a jar. The cap has inclined cantilevered tines which activate only in one direction, i.e. they slide over the surface of the sheet when the cap is screwed onto the container without causing damage but the tines will dig into and break the sheet if the cap is unscrewed. As a result tampering can be observed by a broken seal seen through the transparent cap. However the tines may not be fully reliable, e.g. if their effectiveness is reduced by creep relaxation or if their ends become blunted to the extent that the cap can be slowly unscrewed without puncturing the sealing sheet.

As a result, a tamper evident closure that provides secure and effective indication that a closure has been interfered with is desirable

Summary

The present applicant has mitigated the above problems by providing a tamper evident closure for a container, comprising: i) an outer cap, ii) a tamper evidencing element, and iii) a marking member operable to mark or damage the tamper evidencing element to provide tamper evidence; characterised in that the tamper evident closure further comprises an inner cap rotationally disengageable from the container; the outer cap being movable relative to the inner cap to bring the outer and inner caps into driving engagement with each other in the rotational disengagement direction, such relative movement causing the marking member to mark or damage the tamper evidencing element and provide the tamper evidence.

Optionally, the marking member is arranged to leave markings on the surface of the tamper evidencing element when it comes in contact with the tamper evidencing element. The marking member can be an ink soaked pad or a felt tip or other pen that dispenses preferably non-erasable ink on contact, or it can he any marker known to the person skilled in the art, for example sandpaper, pencil, chalk and wax crayon.

Optionally, the marking member may comprise a blade provided on one of the outer or inner cap and which co-operates with a counter-blade or edge provided on the other one of the outer or inner cap to damage the tamper evidencing element. The damage inflicted on the tamper evidencing element may range from mere surface indentation to an observable incision, puncture, scratch, cut, abrasion or the like.

Optionally, the relative movement between the outer and inner caps comprises rotation; as such a single rotational movement in the disengagement direction can destroy the tamper evidencing element and disengage the tamper evident closure from the container. Optionally, one of the inner and outer cap comprises an eccentric stop and the other of the inner and outer cap comprises a pair of co-operating stop faces arranged to limit the range of movement of the eccentric stop. Optionally, one of the inner and outer caps comprises a projecting guidance member and the other of the inner and outer cap comprises a guide track in which the guidance member is received Additionally or alternatively, the relative motion between the outer and inner caps comprises axial movement. For example to remove the tamper evident closure a downward force may be required to move the outer cap towards the inner cap before applying a rotational force in the disengagement direction. Optionally, the tamper evident closure comprises a ratchet mechanism acting between the inner and outer caps so as to allow relative rotation between them in the closure rotational disengagement direction and so as to prevent relative rotation between the inner and outer caps in the closure rotational engagement direction. Optionally, the tamper evident closure comprises a dog clutch acting between the inner and outer caps and which is engaged by the relative axial movement. As such the tamper evident closure may be screwed onto the container in the closure rotational engagement direction, without the need of engaging the dog clutch that would otherwise damage the tamper evidencing element. Optionally, the tamper evident closure comprises a resilient pawl arranged to bias the dog clutch out of engagement to prevent unintentional damage dealt to the tamper evidencing element. Optionally, the relative motion between the inner and outer caps comprises rotation and axial movement. The axial movement may bring the tamper evidencing element and marking member into operative engagement, whereby the rotational movement causes the marking member to mark the tamper evidencing element.

Other mechanisms are available for protecting the tamper evidencing element from unintentional damage. For example and optionally, the outer and inner caps are releasably secured together to resist the relative movement prior to application of the closure to a container. Optionally, the resistance to relative movement is provided by frictional engagement between or a frangible connection between the outer and inner caps.

Optionally, the inner cap is snap-fitted into the outer cap. Advantageously the inner cap is not removable from the outer cap and thus cannot be tampered with once it is assembled into the outer cap.

Optionally, the tamper evidencing element comprises a markable sheet. Optionally, the sheet carries surface markings, e.g. security markings which are preferably difficult to reproduce. Optionally, the sheet comprises a hologram. These security measures make the sheet more difficult to counterfeit. Optionally, the tamper evidencing element is visible through the outer cap; for example the outer cap may be made of any translucent or clear material such as organic polymers (e.g. PET, HDPE or PLA), or it can be made of opaque material with a sight window or slit built into it so that the tamper evidencing element is visible. Alternatively the tamper evidencing element may be concealed within the cap (which may therefore be opaque) but can be revealed by opening (e.g. breaking open) a part of the cap. The cap may be configured so that such opening can take place with the cap in place to close a container.

Optionally, the tamper evidencing element comprises an RFID device, or NFC (near field communication) device, or any other information carrier in which the information (such as recorded or stored digital information) is damaged, altered or lost upon relative movement of the inner and outer caps. In this case the outer cap may be opaque since the integrity of the RFID/NFC device or other stored information may be assessed using a suitable scanner or other interrogation device and with the cap intact.

Optionally, the tamper evidencing element projects across a groove formed in the inner or outer cap.

Optionally, the tamper evident closure comprises a tamper evident ring frangibly connected thereto and arranged to engage with the container when the closure is applied to the container.

Optionally, the tamper evidencing element and the tamper evident ring each comprise at least one matching serial number, as such provides additional tamper evident protection against pilferage. This serial number pairing may he unique to each individual container, or it can be a common serial number shared by a batch of product.

Optionally, the tamper evidencing element is sandwiched between respective end walls of the inner cap and the outer cap.

Brief Description of the Drawings

Further features and aspects of thc present invention will he apparent from the lollowi ng detailed desenpnon of illustrative embodiments made with reference to the drawings. in which: Figure 1 is a perspective 1e showing a first embodiment of the tamper evident closure in an Iffidalliaged condition; Figure 2c are perspective views showing a sequence of steps in the removal of the tamper evident closure shown in I from a container neck (not show ii); Figure 3 is a perspective sectional view of a tamper evident closure similar to that of the preceding figures, showing the engagement between the tamper evident band and a container; IS Figure 4 is a perspective sectional 'iew ol a tamper evident CIOStlit according to a second embodiment of the present invention; Figure 5a to Figure Sc are schematic cross sectional views ikf tamper evident chisure being assembled onto and removed. Ii- the second embodiment Figure 6 is a perspective sectional view of a tamper evic 20 embodiment of the present invention; ccorcling to a thirc Figure / is a perspective sectional view of a tamper evident closure according to a fourth embodiment of the present invention; Figure 8 is a diagrammatic partial cross section showing a side view of a tamper evident closure, according to a fifth embodiment of the present in Figure 9a an igum b are respective diagrammatic top and side views of the inner cap shown in Fig, 8; Figure 1 Oa and Figure 10b show respectively a plan view of the inside and a cross-section on a diameter of the outer cap of Fig. 8; Figure lia to Figure lie show t sixth embodiment of ur Figure 12 shows a seventhembodiment of thc invention which is a variant of the sixth entbi lent; Figures 1 15 show variants of the embodiment of Figure 12, a Figures 16 and 17 show respective further variants if the cap assemblies of Figures 12-15.

Detailed Description

Figure 1 shows an example of tamper evident closure 10, comprising a transparent outer or driving cap 20 snapped over an inner or driven cap 30. The driven cap is internally threaded so as to be rotationally engageahle with/disengageable from an external screw thread on the container neck (not shown). A tamper evidencing element 40 is sandwiched between respective end walls of the outer cap 20 and the inner cap 30. A degree of free relative movement exists between the inner cap 30 and outer cap 20. In Figures 1 and 2a-2c this free relative movement takes place in the rotational direction. In order to drivingly engage IS the inner cap 30 and remove the tamper evident closure 10 from the container neck, the outer cap 20 must maneuver within the degree of free movement; doing so marks or damages the tamper evidencing element 40.

As shown in Figure 1, the tamper evidencing element is a holographic label 40 imprinted with alphanumeric and QR / bar codes. The codes may comprise a product identifier or a batch number, or they could comprise a unique serial number for label 40. The QR or bar codes may he scanned directly through the transparent outer cap 20, which also permits the visual inspection of the label 40. In some other cases an opaque outer cap 20 with a sight window, i.e. a transparent or cut out section, may be used, in which the label may be inspected through the sight window. Unscrewing the tamper evident closure marks or damages the label 40. The enclosed position of the label and the use of a hologram ensures the label cannot be counterfeited and replaced easily by unauthorised persons. Other tamper evidencing elements are equally applicable, for example partial residue security labels. UV/luminous markings, labels woven with security threads, pockets of dye and pearlescent label coatings.

Alternatively, the outer cap may be opaque and serves to conceal the tamper evident element. As such the existence of the tamper evidencing element is unknown to casual observers; its condition can only be assessed via an appropriate scanner. One example is passive RFID tags which rely on a two dimensional coiled induction circuit to induce power inside a magnetic field. Unscrewing the tamper evident closure severs the circuit and disables the RFID, rendering it unresponsive to a scanner. Other NFC devices may also or alternatively be used, which are broken or disabled by appropriate relative movement of the inner and outer cap parts. Scannable tamper evidencing elements such as RFID tags/NEC devices, optionally destroyed or disabled on opening the closure, may also form part of a visible security seal 40. Yet alternatively, the outer cap may be opaque, with a top wall portion which may be broken out or is otherwise openable to reveal the tamper evidencing element, which may be of any of the kinds described above.

Once the inner cap 30 is assembled into the outer cap 20 the two are preferably inseparable without destruction or visible damage. Guidance members protruding from either the outer cap or inner cap are received in complementary tracks or arcuate slots in the other of these two parts. In the example illustrated most clearly in Figures 1 and 2a, there is a degree of relative free rotational movement between the inner and outer caps in the circumferential direction; two pairs of guidance members 32 and 24 travel along respective tracks 22 and 34 in the circumferential direction. The length of the tracks 22 and 34 dictates the degree of free movement and in this case a free relative circumferential (relative rotational) movement of a little less than 180° is permitted. In the illustrated example the tracks 34 are formed as a pair of arcuate slots extending from the outer face of the end wall of the inner cap 20 part way through the thiclmess of this end wall, and the guidance members 24 are tabs projecting downwardly from the outer face of the outer cap end wall into the slots 34. The slots 22 on the other hand are formed on the inner surface of the skirt portion of the outer cap 20 and extend part way through its thickness. The guidance members 32 project into these slots from the outer surface of the skirt portion of the inner cap 30. The angle subtended by the free part of arcuate slots 22 is equal to the angle subtended by the free part of arcuate slots 34. Slots 22 and guide members 32 provide a permanent snap-fit interengagement between the inner and outer caps 30, 20. This interengagement is enhanced by a continuous circumferential groove 38 towards the upper end of the inner surface of the outer cap skirt, into which is snap-fitted a circumferential ridge 42 projecting from the upper part of the outer surface of the inner cap skirt.

Other suitable configurations for the slots 22, 34 and guidance members 24,32 will be readily apparent. At their simplest, the guidance members may comprise an eccentric stop on one of the inner and outer caps, whose range of movement is limited by a pair of cooperating stops or stop faces on the other of the inner and outer caps. In the illustrated example the eccentric stop is the guidance member 24 or 32, and the co-operating pair of stop faces are the ends of the corresponding slot 22 or 34 respectively. Some or all of the slots 22, 34 and the corresponding guidance members 24, 32 may be omitted; or the positions, as between the inner and outer caps, of any of the co-operating pairs of slots and guidance members (protuberances), may be reversed, individually, collectively or in any combination.

The outer cap 20 further comprises a marking member in the form of at least one knife member 26 protruding from the inner surface of its end wall into a corresponding circular groove 36 in the outer surface of the end wall of the inner cap 30. The tamper evidencing element is adhered to this outer surface, spanning the groove 36. In this example the knife member is formed by three pins 26 which serve to slice through and destroy the tamper evidencing element as the outer cap 20 is rotated within the degree of free movement. The pins 26 can be in any shape and form so long they are capable of breaking or otherwise marking the tamper evidencing element 40 upon relative movement between the inner and outer caps 30, 20; for example flat blades; or biased cantilevers that inflict damage on the tamper evidencing element 40 only in the direction of closure disengagement. However knives or pins on one of the inner or outer cap running against an edge overlain by the tamper evidencing element (as provided by the upper edges of the groove 36) are effective, because they cut through the tamper evidencing element 40 reliably and efficiently with a shearing or scissor-like action to provide a visible mark. A configuration of three pins or knives 26 as shown ensures that at least one pin/knife will puncture the tamper evidencing element upon assembly of the inner and outer caps. Any significant relative rotational movement of the inner and outer caps 30, 20 will result in elongation of this puncture and thus be visibly recorded. The inner and outer caps in the illustrated example are assembled with the guidance members 24 at the extreme clockwise leading ends of the tracks 34 and the guidance members 32 at the extreme clockwise trailing ends of the tracks 22, so that there can be no relative movement between the inner and outer caps 30, 20 as the closure is screwed onto the container neck (using a right hand thread). The tamper evidencing element 40 therefore remains undamaged (save for the initial punctures) as the closure 10 is applied to the container for the first time. This is also the case of course if the closure is pressed onto the container neck thread rather than being screwed on. To ensure that the inner and outer caps 30, 20 remain in the initial position shown e.g. during storage and transportation prior to application to a container, e.g. at a filling line, the inner and outer caps may comprise frictionally engaged raised areas or pads (not shown) which disengage from one another after slight rotation of the outer or driving cap 20 in the anticlockwise or unscrewing direction relative to the inner or driven cap 30. This frictional resistance is arranged to be less than the initial unscrewing resistance between the inner cap thread and the container neck thread when fully torqued, so that there will he movement between the inner and outer caps as the closure is unscrewed. Alternatively, a frangible connection, such as a frangible pin-and-socket connection between the inner and outer cap end walls (not shown), or a snap in/snap out detent, may be provided to hold the inner and outer caps in their fixed initial relative position; otherwise operating in the same way as the described frictional connection.

In some cases (not shown) the length of the pin or knife 26 is shortened and its lead edges are blunt so that it only leaves an indentation or scratch on the surface of the label (or other tamper evidencing element) 40. In some other cases (not shown) a marker is installed in place of the pin or knife 26 so that upon activation the marker leaves a mark and/or indentation on the surface of the label 40. Any suitable marking member operative to mark any suitable tamper evidencing element (such as those described herein, or others) may he used in any of the embodiments described herein.

Figures 2a to 2c animate the unscrewing and removal of a tamper evident closure 10. Figure 2a shows an assembled tamper evident closure where the tamper evidencing element 40 is intact/unmarked and the guidance members 32, 24 are at the clockwise trailing and leading ends of their corresponding tracks 22, 34 respectively. As the outer cap 20 is rotated anticlockwise within the degree of free movement, as shown in Figure 2b, the pins 26 slice through the tamper evidencing element 40, causing irreversible damage in the process. The guidance members 32, 24 follow their corresponding tracks 22, 34 and help to ensure the pins 26 adhere to a fixed cutting path. Figure 2c illustrates the onset of unscrewing the tamper evident closure 10 from the container; as the guidance members 32, 24 reach the other (clockwise leading and trailing) ends of their respective tracks 22, 34. Here they lock the outer cap in driving engagement with the inner cap 30 to allow removal the tamper evident closure 10. In the Figure 2c position, the knives 26 have travelled the entire length of those portions of the groove 36 overlain by the tamper evidencing element 40, so that end portions of the tamper evidencing element are completely severed from the centre portion; thereby providing highly visible tamper evidence, and/or destroying an RFID induction coil.

NFC device, or the like embedded in the tamper evidencing element 40.

In some applications the outer cap 20 may be removably secured onto the container to protect against accidental movement and/or to provide a further tamper indicating mechanism, with the use of a tamper evident ring or band. As shown in Figure 1 and Figure 3, a tamper evident band 50 may be formed with the outer cap 20 and the two are connected by frangible links 54 at the mouth of the outer cap 20. Resilient ratchet blades 52 on the tamper evident band engage with a set of matching teeth 53 on the container neck (Figure 3) to ensure the outer cap 30 is secured. The blades extend inwardly from the band 50 inclined in the anti-clockwise direction so the tamper evident closure can be screwed onto the container in the clockwise direction with the ratchet blades riding over the container neck teeth without detaching the tamper evident hand. On unscrewing the closure, the ratchet blades jam against the neck teeth, so that the hand 50 cannot rotate with the outer cap 20, and the frangible links 54 are broken. In some cases the serial number displayed on the label 40 is also printed the tamper evident band 50 to provide additional tamper evident protection. For example, a pilferer may need to prepare an additional cap with counterfeited tamper evident band 50 in addition to counterfeited label 40 for pilfering the material in the container. In the example shown in Fig. 3, the tamper evident closure has no guide tracks and guidance members in the end faces of the inner and outer caps. But the closure is still equipped with guide tracks 22 and guide members 32 and a circumferential groove 38 and circumferential retaining ridge 42 in the inner and outer cap skirts. These act in the same way as in the previously described examples. The caps described below with reference to Figures 4-7 are also similar in this respect.

Figure 4 and Figures 5a-c show an example closure equipped with a tamper evident band 50b that fits substantially flush with the outer cap 20. The tamper evident band 50b consists of an upper element 56 and a lower element 58 connected via a living joint 59. Thus the lower element 58 may pivot inwardly to form an elbow or in-turned hem. During assembly the entire tamper evident closure is screwed and lowered onto the container 60, enabling the in-turned elbow or hem to expand, ratchet past and then contract to lock beneath a circumferentially extending ridge 62. In removal, the tamper evident closure 12 is unscrewed from the container 60. The elbow or hem 58 jams beneath the ridge 62 and separates the outer cap 20 from the tamper evident band 50b along a line of weakness 54a.

To aid the ratcheting, the upper surface of the ridge 62 is frusto-conically tapered. To aid the jamming, the lower surface of the ridge 62 extends substantially in a flat plane, normal to the closure centre axis.

Alternatively, the inner cap 30 may comprise an additional secondary tamper evident band 30c similar to the tamper evident band 50b, as shown in Figure 6. In this case the secondary tamper evident band is of the same general kind as shown in Figures 4 and 5a-c, i.e. comprising a turned in element lockable beneath a ridge on the container neck. The secondary tamper evident hand 30c is attached to the inner cap along a secondary line of weakness 54e with its lower turned-in element 58c locked beneath a secondary ridge 62c.

As such, in removing the tamper evident closure, both lines of weakness 54a, 54e break, leaving the tamper evident band 5019 and secondary tamper evident band 30c captive on the neck of the container.

In yet another embodiment, shown in Figure 7, the tamper evident closure 10 comprises a secondary tamper evident band 30c on the inner cap, of the same general kind as shown in Figures 4 and 5a-c. A tamper evident band 50 is provided on the outer cap, of the same general kind as shown in Figures 1 and 3. That is, the tamper evident band 50 comprises resilient ratchet blades engageable with teeth on the container neck to allow relative rotation in the screwing on direction but to resist relative rotation in the unscrewing direction. The bands 30c and 50 provide tamper evidence against axial and circumferential movement respectively. Both bands 30e, 50 are separated from the remainder of the closure once the tamper evident closure 10 is removed. Band 30c remains captive on the container neck. In some cases a pair of matching serial numbers are printed onto the label 40 and the tamper evident band 50 to provide additional tamper evident protection. Alternatively only the inner cap may be provided with a tamper evidencing band. This may be of either of the kinds described above. Indeed, any suitable known tamper evidencing means may he used on the inner and/or outer cap, without restriction to the specific kinds shown, e.g. other kinds of tamper evidencing bands, frangible seals or the like.

A third level of anti-tamper protection can be provided if desired by using a tear-out sealing foil or membrane across the mouth of the container neck, for example a frangible foil induction heat sealed or otherwise bonded to the rim of the container neck. This must be torn off or ruptured to mach the container contents after removal of the cap.

Alternatively, the relative movement between the inner and outer caps can he arranged in the axial direction, the working principle being similar to that of child proof caps. Figure 8 illustrates such a tamper evident closure, constructed from the inner 30 and outer 20 caps shown in Figure 9a/9b and 10a/10b respectively. Ratchet teeth 76 upstanding from the inner end face of the outer cap 20 form a ratchet rack engaged by resilient pawls 70 upstanding from the outer end face of the inner cap 30, so as to allow relative rotation between the inner 30 and outer cap 20 only in the closure rotational disengagement direction. As such, during assembly, i.e. on a filling line in a factory, the tamper evident closure 10 can be screwed directly onto the container (not shown) in the closure rotational engagement direction, because the pawls 70 engage the ratchet teeth 76 and cause the inner cap to rotate together with the outer cap. When simply attempting to unscrew the cap, the pawls 70 ride over the ratchet teeth 76 so that the outer cap rotates relative to the inner cap without loosening it from the container neck thread (not shown). However when an axial force is applied to the outer cap 20 against the bias of resilient pawls 70, the outer cap moves downwardly relative to the inner cap. The ratchet teeth 76 of the outer cap 20 then engage with a dog clutch of the inner cap 30, formed by three dogs 72 upstanding from the outer end face of the inner cap, interspersed with the resilient pawls 70. As such the inner and outer caps drivingly engage one another so that tamper evident closure 10 may be removed from the container (not shown) when it is subsequently unscrewed in the closure rotational disengagement direction. To retain the inner cap in the outer cap while allowing the necessary axial movement of the outer cap 20 against the bias of the resilient pawls 70, an outer circumferential ridge 42 on the inner cap 30 is snap-fitted into a wider inner circumferential groove 38 in the outer cap 20.

The marking member given in the example in Figure 8 to Figure 10b is an annular punch 74 projecting axially from the inner end face of the outer cap 20. In use, the annular punch 74 is pushed towards a receiving groove 36 formed in the outer end face of the inner cap 30. This punctures and severs the tamper evidencing element 40 which is secured across the receiving groove, before the ratchet teeth 76 are able to drivingly engage with dog clutch 72. Therefore the tamper evidencing element 40 will break before the tamper evident closure can be removed from the container. The marking member of the outer cap 20 is not limited to the annular punch 74 shown here but it may be pins, blades or any protrusions with a customized profile. It may also be an ink or other marking substance-bearing pad, pen, pencil, crayon or the like. In that case, the groove 36 may be omitted. The marking member and/or the tamper indicating element may be resilient or resiliently mounted to their respective caps, particularly in cases where high axial forces are not needed to effect the marking. This may permit continued relative axial movement between the two caps so as to bring about deeper engagement between the clutch components after initial engagement between the marking member and the tamper indicating element. The positions of the punch and receiving cavity/groove (marking member and tamper indicating element) may be reversed with respect to the inner and outer caps; as may be those of the pawls/dogs and ratchet teeth.

Figures 1 la-c show a sixth embodiment of the invention, in which there is both relative rotational and relative axial movement between the inner and outer caps in use. Figure 1 la shows the (transparent) outer cap 20 and (transparent or opaque) inner cap 30 prior to assembly. Translucent variants of the outer cap may also be used, as discussed above. For completeness, a container 60 and container neck 100 are also shown; although in practice the caps will usually be supplied and assembled separately from the containers. The inner cap has an external circumferential retaining ridge 102. Below this are a series of raised areas 104, each of the same shape, and all circumferentially spaced around the inner cap exterior, so as to define gaps or gateways 106 between them. The vertical spacing between the retaining ridge 104 and raised areas 104 defines a retaining groove 110 on the outer surface of the inner cap, into which can be snap-fitted an internal circumferential retaining ridge 98 on the outer cap. The width of the groove 110 is greater than the width of the ridge 98, to allow a degree of captive vertical movement between the interengaged inner and outer caps. As shown in Figure 11a, the inner and outer caps are not yet assembled, so the ridge 98 lies above the ridge 102, rather than in the groove 110.

Similarly to the embodiment shown in Figure 1, the cap assembly of Figures 1 la-e comprises a tamper evidencing element 40, such a holographic label, secured across a circular groove 36 in the top exterior face of the inner cap 30. The tamper evidencing element is visible through a transparent top wall of the outer cap 20. This top wall carries a series of knife members 26 aligned with the groove 36, for severing the tamper evidencing element when the cap assembly is unscrewed from a container. However, as further described below and in contrast to the Figure 1 embodiment, in the assembled cap, the knife members 26 are not permanently engaged in the groove 36. Similarly to the Figure 1 embodiment, the outer cap 20 of Figures 1 la-c has a tamper evidencing band attached to it by frangible links 54. The band is again provided with resilient ratchet blades 52 which co-operate with ratchet teeth 53 suitably positioned about the container neck 100.

The gateways 106 each lead into the upper limb of a "lazy Z" shaped guideway groove 112 on the outer surface of the inner cap (perhaps more clearly seen in Figure 11b, where they are not obscured by overlying edge features of the outer cap). Each guideway has a circumferentially extending upper limb 112a, a central transition portion 112h extending diagonally downward and rightward from the right hand end of the upper limb, and a lower limb 112e extending circumferentially rightward from the bottom end of the transition portion. (In this and the following description, the directions "left" and "right" are with respect to the visible front face of the assembly when viewed from a particular direction. As applied to relatively rotating or rotationally synunetric components, naturally these directions will be reversed in the invisible view, considered from the same viewpoint). The outer cap is provided with a series of circumferentially spaced nocks, keys or guidance members 108 protruding inwardly from its interior surface. These are circumferentially distributed in the same pattern as the gateways 106. For assembly, the inner and outer caps are rotated relative to each other until the nocks 108 on the outer cap find the gateways 106 in the inner cap. Axial pressure (e.g. by hand or from a spring loaded or similar assembly tool) will cause the nocks 108 to enter the gateways 106 when the two are rotationally aligned. Continued axial pressure will cause the retaining ridge 98 on the outer cap to snap past the ridge 102 on the inner cap and into the inner cap groove 110. This holds the inner cap captive in the outer cap. At the same time, the nocks 108 will pass through the gateways 106 and enter the guideway upper limbs 112a. The assembled caps can be delivered to a customer in this condition, for use on a container filling line. If desired, the outer cap can be rotated slightly anti-clockwise relative to the inner cap, to more fully engage the nocks 108 in the guideway upper limbs 112a. Frictional resistance is sufficient to prevent significant further movement between the inner and outer caps in transit and handling. Reception of the flocks 108 in the guideway upper limbs 112a holds the knife members 26 spaced above and disengaged from the groove 36, out of contact with the tamper evidencing element 40. Prior to use of the cap assembly, the tamper evidencing element is therefore protected against accidental damage.

At the filling line, when the cap assembly starts to be screwed onto the container neck, the outer cap 20 is driven in the clockwise rotation. Frictional resistance with the neck thread will brake rotation of the inner cap 30. The nocks 108 will therefore move to the left along the guideway upper limbs 112a until they reach a stop position at the blind extreme left end of the guideway (see Figure 11c). Then the nocks will drive the inner cap to rotate with the outer cap, screwing the cap assembly onto the container neck, to its final desired torque.

Note that in this position the knife members 26 are deactivated, as they still do not touch the tamper evidencing member 40, being above and disengaged from the groove 36. During this process, the resilient blades 52 located at the tamper evident band 50 engage with the ratchet teeth 53 to prevent any unintentional movement of the outer cap relative to the inner cap in the opening direction, which might otherwise cause damage to the tamper-evidencing element 40.

When the end user desires to remove the cap assembly 10 from the container neck 100, they rotate the cap assembly anticlockwise to unscrew it in the usual way (for a right hand threaded connection). At this stage the frangible links 54 connecting the outer cap 20 with tamper evident hand break, as the band is locked to the container neck 100 against anticlockwise rotation, by engagement of the resilient blades 52 between the neck ratchet teeth 53. The inner cap 30 at this stage remains frictionally held on the neck thread at the specified torque. The nocks 108 therefore travel to the right along the entire length of the guideway upper limbs 112a. The nocks 108 are prevented from entering the gates 106 by engagement of the outer cap ridge 98 with the lower side of the inner cap ridge 102.

The nocks 108 therefore enter the guideway transition portions 112b. Continued anticlockwise rotation of the outer cap 20 on the inner cap 30 (which is still frictionally held on the neck thread) causes the outer cap to be cammed downwardly relative to the inner cap, as the nocks 108 are guided downwardly and to the right by the guideway transition portions 112b (see Figure 11 e); with the ridge 98 moving down across the width of the groove 110. This activates the knife members 26 by bringing them into engagement with the groove 36, and with those portions of the tamper-evidencing element 40 spanning it. Continued rotation of the outer cap on the inner cap therefore severs the tamper evidencing element 40 and causes the nooks 108 to move to the right along the entire length of the guideway lower limbs 1 12c.

Then the nocks 108 meet the blind ends at the extreme right of the guideway lower limbs 112c. This provides a stop which places the outer cap into driving engagement with the inner cap. The inner cap now rotates anticlockwise together with the outer cap, and the entire assembly is unscrewed from the container neck. Replacing the cap assembly on the container neck, e.g. after dispensing container contents, causes the outer cap to rise again relative to the inner cap, in the course of tightening them both onto the neck thread.

Figure 12 is a diagrammatic perspective view of part of the outer surface of an inner cap 30, which is used in a modification of the embodiment shown in Figures ha-c. The construction and operating principles of the two embodiments are generally similar, with the following main differences. These differences enable the inner and outer caps of the Figure 12 embodiment to rotate through a larger angle relative to each other after activation of the knife members 26, potentially allowing them to cause more visible damage to the tamper evidencing element 40.

The outer surface of the inner cap 30 comprises a circumferential retaining ridge 102, for snap fit co-operation with a corresponding internal circumferential retaining ridge 98 on the outer cap. Similarly to the previous embodiment, ridge 102 has a downwardly and outwardly sloped or chamfered upper surface, and a generally flat planar lower surface; whereas ridge 98 has an upwardly and inwardly sloped or chamfered lower surface and a generally flat planar upper surface. Thus the two ridges are a "one-way snap-fit" past each other; being reasonably easily snap-engaged upon insertion of the inner cap axially into the outer cap; but very difficult or impossible to disengage again without breaking or visible damage.

A circumferential barrier ridge 114 is positioned below the retaining ridge 102. Apart from the usual slightly radiussed corners and root areas, barrier ridge 114 has a generally rectangular cross-section. It has a width d in the cap axial direction and its upper face is spaced a distance h+x below the lower face of the retaining ridge 102, where h is the height of the noels (i.e. their size in the cap axial direction) and x is a small clearance which may be substantially zero. The width of the groove 110 between the retaining ridge 102 and the barrier ridge 114 is thus h+x.

The nocks on the inside of the outer cap 20, rather than all being circumferentially distributed in a single set at a single level along the outer cap axial direction, are instead provided in two separate circumferentially distributed sets, each set being at a different level with a vertical clearance of d+y between them; where y is a small clearance of the same order as, but not necessarily equal to, x. The circumferential distribution pattern of the nocks in each set is the same, but the lower set is rotationally displaced from the upper by an angle 0 in the anticlockwise direction, when viewed from above the cap. For the purposes of this description, the term "set" used in relation to the 'locks can include a single nock. The preferred number of nocks in a set is two, although larger numbers may also be used. Two nocks can provide an optimum balance between strength, stability of snap-fit performance, and high useful "activated" angular movement. The nocks in each set may be evenly spaced around the cap circumference, though this is not essential. A neck in one set may be evenly offset from each of the two neighbouring nocks in the other set. Thus, with two nocks in each set, 0 is preferably 90 degrees, although other angles are also effective.

The bottom edge of the inner cap 30 is optionally provided with a circumferential lower guide ridge 118, having an upwardly facing surface spaced a distance d+2h+z from the downwardly facing surface of the barrier ridge 114, where z is a small clearance of the same order as, but greater than, .K. The barrier ridge 114 and the lower guide ridge 118 are therefore separated by a lower groove 120 of width (-1+2h+z.

The retaining ridge 102 and the barrier ridge 114 are each interrupted to form a number of gaps or gateways 116 circumferentially aligned with each other and in the same distribution pattern as the nocks (of one of either set). Thus, if there are two lower nocks and two upper nocks (i.e. the preferred arrangement of two nocks in each set), there are two gateways 116 (only one of which is visible in Figure 12). The width of the gateways is slightly greater than the length of the nocks in the cap circumferential direction, to provide a small clearance.

Assembly of the inner and outer caps proceeds as follows. The inner cap is inserted coaxially into the outer cap, until the retaining ridge 102 encounters the lower set of nocks. The inner and outer caps are then rotated relative to one another, so that the lower set of nocks finds the gates 116 in the retaining ridge 102 and drops through them, into the gates 116 in the barrier ridge 114 below. This brings the upper set of noels into contact with the retaining ridge 102. Axial pressure is then applied to the inner and outer caps, to snap the upper set of flocks past the retaining ridge 102 and into the groove 110. This causes the lower set of nocks to drop through the gates 116 in the barrier ridge 114, so as to lie just below the barrier ridge 114, in the lower groove 120. The nocks thus straddle the bather ridge 114 and the inner and outer caps are retained together by the upper set of nocks in the groove 110, at an angular distance 0 clockwise of the gates 116 when viewed from above the cap assembly. With the nooks straddling the bather ridge 110, the knives 26 or other marking members are deactivated, being held clear of and above the tamper evidencing element 40/groove 36. The cap assembly can he delivered to a container filler in this condition. Frictional resistance between the inner and outer caps may be sufficient to retain the assembly in this relative angular position during storage and shipping, before it is first applied to close a container. Prior to use of the cap assembly, the tamper evidencing element is therefore protected against accidental damage. However if, prior to such use, there is sufficient accidental rotational displacement of the inner and outer caps to bring the upper set of nocks into alignment with the gates 116, the lower set of nocks will be displaced anticlockwise from the gates 116 by an angular distance 0, so as to be prevented from moving upwardly by the barrier ridge 114. The inner and outer caps therefore remain locked together. The retaining ridge 98 is axially positioned in the outer cap 20 so that its upper face is at a distance d+h+v above the lower face of the retaining ridge 102 on the inner cap 30, when the inner and outer caps are in this configuration. v is approximately equal to z/2.

At the filling line (or as an assembly step prior to shipping the cap to the container filler), the cap assemblies are rotated initially in the anticlockwise direction under downward pressure. The inner cap is braked e.g. by frictional contact with the container neck thread, or e.g. using an assembly tool. This allows the upper set of nocks to find the gates 116 in the barrier ridge 114, so that they drop through towards the lower groove 120, as the inner and outer caps are pressed axially together. This brings the outer cap retaining ridge 98 into contact with the inner cap retaining ridge 102. At this point, the upper set of nocks is in the gateways 116 in the barrier ridge 114, and the lower set of nocks is in a middle zone of the lower groove 120, at an angular distance 0 clockwise of the gates 116. The inner and outer caps are now locked together against relative rotation by the upper nocks in the barrier ridge gateways 116.

At the filling line the cap assembly can now he subjected to higher downward pressure, so as to snap the retaining ridge 98 past the retaining ridge 102 and into the retaining groove 110. This activates the knife members 26, which enter the groove 36 in a position clear of the tamper evidencing element 40. The axial pressure may also he used to ratchet the inner cap thread over the container neck threads in some designs, as is known per se.

A lower stop 122 is provided in the rotational path of the lower nocks, e.g. extending upwardly into the lower groove 120 from the lower guide ridge 118, where present. The lower stop 122 has an anticlockwise directed face positioned at an angular distance 0 anticlockwise of the clockwise edge of the gates 116. Thus, as the outer cap retaining ridge 98 snaps into position in the retaining groove 110, the lower nocks drop into position immediately next to and anticlockwise of the lower stop 122. Optionally an upper stop 126 is provided in the lower groove 120 in the rotational path of the upper nocks. The upper stop 126 has an anticlockwise directed face in alignment with the clockwise edges of the gateways 116. In the embodiment shown in Figure 12, the upper stop 126 depends from the barrier ridge 114 on the clockwise side of the gate 116 and its anticlockwise directed face is a continuation of the clockwise edge of the barrier ridge gate. Driving the outer cap in clockwise rotation will therefore cause the lower nooks to engage the lower stops 122 and the upper nocks to engage the upper stops 126, and thereby drive the inner cap to rotate clockwise together with the outer cap. The cap assembly is thereby screwed onto the container neck thread, e.g. to a specified final torque, as is known practice. The filled and closed container is now ready to enter the supply chain for delivery to the end user.

One or more frictional detents 124 may be provided, which extend into the rotational paths of the lower and/or upper nocks, spaced from the respective stops 122, 126 in the anticlockwise direction a distance slightly greater than the width of the respective nocks (only a lower nock frictional detent 124 being shown in Figure 12). The frictional detents 124 prevent inadvertent movement of the knife members in the anticlockwise direction relative to the tamper evidencing element 40 e.g. during handling in the supply chain, before the container is deliberately opened for the first time by the end user. Where the cap assembly includes a tamper evidencing band which locks the outer cap to the container neck, preventing rotation in the unscrewing direction until a frangible connection is broken (e.g. like the band and frangible connections 54 in Figures 1 and 11a, which lock onto the ratchet teeth 53 via the flexible blades 52), the frictional detent 124 may not be necessary. However, where such a tamper evidencing band is absent or does not lock the cap assembly to the container neck against unscrewing rotation (e.g. "flush" band designs as shown in Figures 4, 5a-c, 6 and 7 (hand 30c)), the frictional detent 124 is useful in preventing inadvertent relative rotation between the inner and outer caps in a direction which could prematurely damage the tamper evidencing element 40. Deliberate unscrewing of the cap firstly causes the lower nocks to snap past the frictional detents (braced by the interengaged retaining ridges 98, 102 and then also by engagement between the upper nocks and the lower surface of the barrier ridge 114, as the upper nocks move out of registration with the gateways 116).

When it is desired to open the container, the outer cap is twisted in the anticlockwise, unscrewing direction. At this point, any anti-tamper band securing the outer cap to the container neck is broken off the outer cap. Because at this time the inner cap shown in Figure 12 is still frictionally held on the neck thread up to the specified torque, the nooks on the outer cap move anticlockwise in the lower groove 120 in the inner cap. The knife members 26 are still engaged in the groove 36 and sever the tamper evidencing element 40. The nocks continue to move anticlockwise in the inner cap lower groove 120 until they encounter the clockwise directed faces of the next set of lower and upper stops 122, 126. Thus, where there are two upper nocks, two lower nocks, two sets of gateways 116, two lower stops 122 and two upper stops 126, the outer cap rotates through almost 180 degrees from its fully tightened position until the nocks encounter the next set of stops. Therefore the knife members 26 also move through almost 180 degrees in their operative position and cause clearly visible damage to the tamper indicating element 40, e.g. completely severing it into several different pieces. The locked together inner and outer caps then both rotate in unison in the anticlockwise direction, the outer cap driving the inner cap via the interengaged noels and stops. In this way the cap assembly is unscrewed from the container neck.

Figure 13 shows a modification of the inner cap of Figure 12, and Figure 14 is an enlarged view of a portion of Figure 13. In Figures 13 and 14, the frictional detent 124 has been moved from its position in the path of the lower nock set as shown in Figure 12, to a corresponding position in the path of the upper nock set. The frictional detent is therefore positioned in the lower groove 120, aligned with the anticlockwise edge of the barrier ridge gateway 116. Thus when the retaining ridge 98 in the outer cap is snapped past the corresponding retaining ridge 102 on the inner cap, the upper nock set drops into the lower groove 120 between the upper stop 122 and the frictional detent 124. Operation of this cap assembly is otherwise similar to that described with reference to Figure 12.

Figure 15 shows a further and somewhat simplified modification of the inner cap of Figure 12. In this modification, the gateways 116 in the inner cap external circumferential retaining ridge 102 are omitted. Also, the width of the lower groove 120 is reduced so as to be equal to the width of the retaining groove 110, h+.T. Finally, in the outer cap 20 (not shown), the set of upper nocks replaces or is replaced by the outer cap internal circumferential retaining ridge 98, which is therefore spaced axially of the set of (lower) nocks by a distance d+y.

Assembly and operation is as follows. The inner cap and outer cap are pressed axially together so that the (lower) nock set snaps over the retaining ridge 102 on the inner cap 30.

The inner and outer caps are thereby permanently connected together, as there are no gateways in the ridge 102. The inner and outer caps may then be rotated relative to each other, so that the (lower) nocks find and drop into the gateways 116 in the barrier ridge 114 (since d>h). The outer cap internal circumferential retaining ridge 98 or the upper set of nocks (whichever is present) now rests against the inner cap retaining ridge 102. The (lower) nocks may be a frictional fit in the gateways 116 (e.g. by the gateways being slightly shallower than the retaining groove 110 and/or by the gateways having a narrowed or waisted centre section of slightly smaller width than the (lower) nocks). This frictional fit holds the inner and outer caps in this relative position for transport and storage prior to their initial installation on a container neck. The knife members at this stage are held deactivated, above and out of engagement with the groove 36 and tamper evidencing member 40, so that there can be no accidental false positive tamper indication. Alternatively, the cap assemblies are supplied to the filling line with the (lower) nocks still in the groove 110. Initial rotation of the outer cap on the inner cap as the assemblies are screwed onto the container necks is then used to drop the (lower) nock set into the barrier ridge gateways 116.

Axial force applied to the cap assembly on the container neck then snaps the upper nock set or outer cap internal circumferential retaining ridge 98 (whichever is present) past the inner 20 cap retaining ridge 102 and into the retaining groove 110. This moves the knife members 26 into activated, operative engagement in the groove 36. The (lower) nock set also moves out of the barrier ridge gateways 116 and into the lower groove 120, between the stop 122 and the frictional detent 124 (where present). The remainder of the operation of this variant is similar to operation of the cap assembly described above with reference to Figures 12-14. 15 The stop 122 and the frictional detent 124 may be provided on the barrier ridge 114 as shown in Figures 13 and 14, rather than on the lower guide ridge 118, as shown in Figure 15. Upper stops (not shown) for co-operation with the upper nocks (where present) may be provided in the retaining groove 110 at an angular distance 0 clockwise of the lower stops, where the upper nock set is displaced by an angle 0 clockwise of the lower nock set. Such upper stops cannot be used where the upper nocks are replaced by the outer cap internal retaining ridge 98.

Figure 16 shows a further variant of the cap assemblies shown and described with reference to Figures 12-15, in which: (a) the inner cap's retaining groove 110 is wide enough to accommodate the set of upper flocks 108u as well as the set of lower nocks 108L and (1)) the number of gateways in the retaining ridge 102 and in the harrier ridge 114 are each equal to the total number of nocks. Hence gateways are provided for both the lower and the upper nocks.

A further lower nock and a further upper nock and con-esponding gateways are provided on the rear face of the assembly, not visible in Figure 16, rotationally symmetrical to those shown. These operate in the same way as the visible components and therefore further description of them is unnecessary. There are several different options for assembly and operation of this variant: Option 1) The inner cap is pressed into the outer cap and the two paris are rotated relative to one another until the lower nock 1081. finds one of the gateways 116a or 116b in the inner cap's retaining ridge 102. The inner cap is further pressed into the outer cap the lower nock passes through that gateway. In this configuration, the upper nock has been rotationally aligned with the other retaining ridge gateway and is able to pass through it, so that both nocks are now in the retaining groove 110. Before the lower nocks 108L enter the lower nock gateways 1161, in the barrier ridge 114, the outer cap is then rotated with respect to the inner cap, so as to position the lower nock 108L anticlockwise of the lower nock gateway 116L. This simultaneously positions the upper nook 108u anticlockwise of the upper nock gateway 116u in the barrier ridge 114 (and of the retaining ridge gateway 116b).

The nocks and gateways may be "coded", so that the lower nock 108L can only pass through the lower nock gateway 116L. For example, the lower nock 108L and the lower nock gateway 1161. may each be wider than the upper nock 108u and its gateway 116u in the barrier ridge 114, so that the lower nock 1081, is too wide to pass through the upper nock gateway 116u. Alternatively, the angular offset between the set of upper nocks and the set of lower flocks may be changed so that a given nock in one set is no longer equidistant from each of its neighboring nocks in the other set. That is, for the cap illustrated in Figure 16, the angular offset between the two sets is no longer 90 degrees. The angular spacing of the barrier ridge gateways 116L, 116u and of the stops 122, 126 are changed to match, such that the lower stop 1081_ again always passes through the lower stop gateway 1161, immediately anticlockwise of the lower stop 122, and the upper stop 1081, always passes through the upper stop gateway 116u immediately anticlockwise of the upper stop 126. The spacing between the locking ridge gateways 116a, 116b in that case has to be similarly changed to allow passage of the flocks 1081_ 108u.

Similarly, the retaining ridge gateways 116a, 116b may be "coded" so that the inner and outer caps always have to be rotated in the same direction relative to one another to bring the nocks into the desired positions anticlockwise of their respective retaining ridge gates 1161_ and 116u during assembly. For example, where a widened lower nock 108Lis used, if the retaining ridge gateway 116a is con-espondingly widened, the lower nock 1161. will always pass through the retaining ridge gateway 116a and the upper nock 108u will always pass through the retaining ridge gateway 116b. The outer cap therefore has to be rotated anticlockwise relative to the inner cap to position the lower and upper nocks 1081., 108u anticlockwise of their respective barrier ridge gates 1161., 116u. On the other hand, with a widened lower nock 1081_. and a correspondingly widened locking ridge gateway 116b, the outer cap has to be rotated clockwise relative to the inner cap, to position a lower noel (the one which is not visible in Figure 16) anticlockwise of the barrier ridge lower nock gateway 116L. In this way the assembly is prepared for delivery to the filling line.

At the filling line, the cap assembly is pressed onto the container neck and rotated clockwise to tighten the screw threaded connection with the container neck. This causes the outer cap to rotate clockwise relative to the inner cap, so that the upper and lower nocks 108u, 1081_ drop through their respective barrier ridge gates 1161, and 116u, so as to engage the anticlockwise directed faces of the lower and upper stops 122, 126 respectively. At the same time the outer cap's retaining ridge 98 snaps past the inner cap's retaining ridge 102 into the retaining groove 110, and the knife members 26 are activated by entering the groove 36. The inner cap is driven to rotate clockwise together with the outer cap, by the interengaged nocks and stops 1161,, 122; 116u, 126. Unscrewing the cap assembly when it is desired to access the container contents works in the same way as described previously: the nocks 1161_, 116u move anticlockwise along the lower groove 120 until they encounter the clockwise directed faces of the stops 122, 126. During this movement the knife members 26 sever the tamper indicating element 26. Upon re-engagement of the nocks and stops 116L, 122; 116u, 126 the outer cap chives the inner cap in the unscrewing direction, freeing the cap assembly from the container neck.

Option 2) The lower and upper nocks are sufficiently vertically spaced so as to be able to straddle the inner cap's locking ridge 102. For initial assembly, the inner cap is again pressed into the outer cap and rotated so that the lower nocks find and pass through the locking ridge gateways 116a, 116b. The gateways and nocks may be "coded" as described above. However, the inner and outer caps are rotated with respect to one another after the lower nocks 108L have passed through the locking ridge gateways 116a, 116b, but before the upper nocks 108u have done so. The lower and upper nocks therefore straddle the locking ridge 102 on the inner cap and hold the inner and outer cap assembled together for delivery to a filling line. There the cap assemblies are pressed downwardly onto the container necks and the outer cap is rotated clockwise. This brings the upper nocks 108u into registration with the retaining ridge gateways 116a or 116b, so that the upper nocks 108u pass through one or other of these gateways. Depending on matters such as the kind of gateway/nock "coding" used (if any), the upper nocks 108u may pass directly downwards through the upper nock gateways 116u in the bather ridge 114 (with the lower nocks 1081, similarly passing straight down into the lower nock gateways 116L). Or the lower flocks 108L may have to move clockwise along the locking groove 110 until they encounter the next set of lower nock gateways 1161, in the barrier ride 114; at which point the lower and upper nocks 108L, 108u are able to pass through the respective gateways 116L, 116u. From there on, the cap application and removal process continues in the same way as described for option I).

Option 3) The lower and upper nocks are sufficiently vertically spaced so as to be able to straddle the inner cap's barrier ridge 114. The inner cap is pushed into the outer cap for initial assembly as in options 1) and 2). The lower nock 108L and the retaining ridge gateways 116a, 116b may be "coded" such that the lower nock 1081, is able to pass through the gateway 116a but is not able to pass through the gateway 116b. In that case, the lower nock may pass straight downward through the gateway 116a and also through the lower nock gateway116L in the barrier ridge 114. The upper nock 108u correspondingly passes straight through the gateway 116b. However, before it enters the gateway 116u, the outer cap is rotated anticlockwise relative to the inner cap, so that the lower and upper nocks 108L, 108u straddle the barrier ridge 114, with the upper nock positioned anticlockwise of the upper nock gateway 116u. The inner cap may be mounted in an insertion tool having a shoulder which limits its depth of insertion into the outer cap so as to be able to perform this rotation step easily. A similar tool may he used where necessary in options 1) and 2). The caps are thereby assembled ready for delivery to the filling line.

Alternatively, the retaining ridge gateways 116a, 116b may be "coded" such that the lower nock 108L is able to pass through the gateway 116b but is not able to pass through the gateway 116a. In that case, it is necessary to rotate the inner and outer caps 90 degrees relative to one another in either direction, to bring the lower nocks into registration with the barrier ridge lower nock gateways 116L. This may make the inner and outer caps less likely to separate accidentally in transit to the filling line. Additionally or alternatively, the lower nock gateways 1161, may be displaced anticlockwise from the position shown. In that case the retaining ridge gateways 116a, 116b are preferably similarly displaced. The hauler ridge upper nock gateways 116u are however maintained in the same position relative to the stops 122 and 126; and the upper and lower nocks are maintained at the same angular displacement from each other. Therefore when the lower nock 108L passes vertically through the lower nock gate 1161,, the upper nock 1086 encounters the barrier ridge 144, rather than the upper nock gateway 116u. This renders unnecessary a separate tool or the like as described above, for controlling the inner cap insertion depth.

At the filling line the cap assembly is fitted to a container neck and downward pressure and clockwise rotation are applied. This causes the nocks 108u and 108L. to move clockwise along the barrier ridge 114 until the upper nock passes through the upper nock gateway 116u. From here on, cap fitment and removal proceeds in the same way as in options 1) and 2).

Figure 17 shows a cap assembly which is similar to that of Figure 16, except that: a) a "flush" anti-tamper band 301 is used to lock the inner cap to the container neck, similar to the anti-tamper band designs as shown in Figures 4, 5a-c, 6 and 7 (band 30c)), b) the lower stops 126 are separated from any lower edge of the lower groove 120, and c) the retaining groove 110 on the outer surface of the inner cap is only sufficiently wide to accommodate a single set of flocks (i.e. a set of coplanar nooks). It can of course accommodate the outer cap locking ridge 98 instead of any nocks, when the inner cap is fully inserted into the outer cap. The inner and outer caps of Figure 17 may therefore be assembled and used in accordance with options 2) and 3) above (and their described variants), hut not in accordance with option 1).

in all of the described cap assemblies, other variants and modifications are possible, for example the positions of the nocks and their co-operating grooves, ridges, gateways, stops and detents may be reversed, as between the inner and outer caps.

Further variations and modifications to the invention will be apparent to the person skilled in the art, while remaining within the scope of the claims.

Claims

CLAIMS1. A tamper evident closure for a container, comprising: i) an outer cap, ii) a tamper evidencing element, and a marking member operable to mark or damage the tamper evidencing element to provide tamper evidence; characterised in that the tamper evident closure further comprises an inner cap rotationally disengageable from the container; the outer cap being movable relative to the inner cap to bring the outer and inner caps into driving engagement with each other in the rotational disengagement direction, such relative movement causing the marking member to mark or damage the tamper evidencing element and provide the tamper evidence.
2. The tamper evident closure of claim 1 in which the marking member is arranged to leave markings on the surface of tamper evidencing element when it comes in contact of the said tamper evidencing element.
3. The tamper evident closure of claim 1 in which the marking member comprises a 20 blade provided on one of the outer or inner cap and which co-operates with a counter-blade or edge provided on the other one of the outer or inner cap to damage the tamper evidencing element.
4. The tamper evident closure of any of the preceding claims in which the relative movement between the outer and inner caps comprises rotation.
5. The tamper evident closure of claim 4, in which one of the inner and outer cap comprises an eccentric stop and the other of the inner and outer cap comprises a pair of cooperating stop faces arranged to limit the range of movement of the eccentric stop.
6. The tamper evident closure of claim 4 or 5, in which one of the inner and outer caps comprises a projecting guidance member and the other of the inner and outer cap compiises a guide track in which the guidance member is received.
7. The tamper evident closure of claim 1 to 3 in which the relative motion between the outer and inner caps comprises axial movement.
8. The tamper evident closure of claim 7, comprising a ratchet mechanism acting between the inner and outer caps so as to allow relative rotation between them in the closure rotational disengagement direction and so as to prevent relative rotation between the inner and outer caps in the closure rotational engagement direction.
9. The tamper evident closure of claim 7 or 8, comprising a dog clutch acting between the inner and outer caps and which is engaged by the relative axial movement.
10. The tamper evident closure of claims 8 and 9, comprising a resilient pawl an-anged to bias the dog clutch out of engagement.
11. The tamper evident closure of any of the preceding claims in which the relative motion between the inner and outer caps comprises rotation and axial movement.
12. The tamper evident closure of claim 11, in which axial movement brings the tamper 20 evidencing element and marking member into operative engagement, and the rotational movement causes the marking member to mark the tamper evident element.
13. The tamper evident closure of any preceding claim, in which the outer and inner caps are releasably secured together to resist the relative movement prior to application of the closure to a container.
14. The tamper evident closure of claim 13, in which the resistance to relative movement is provided by frictional engagement between or a frangible connection between the outer and inner caps.
15. The tamper evident closure of any preceding claim, in which the inner cap is snap-fitted into the outer cap.
16. The tamper evident closure of any preceding claim, in which the tamper evidencing element comprises a markable sheet.
17. The tamper evident closure of claim 16, in which the sheet carries surface markings.
18. The tamper evident closure of claim 16 or 17, in which the sheet comprises a hologram.
19. The tamper evident closure of any preceding claim, in which the tamper evidencing element projects across a groove formed in the inner or outer cap.
20. The tamper evident closure of any of the preceding claims, in which the tamper evidencing element is visible through the outer cap.
21. The tamper evident closure of any of the preceding claims, in which the tamper evidencing element comprises an information carrier or storage means and in which the information is damaged, altered or lost upon relative movement of the inner and outer caps.
22. The tamper evident closure of any preceding claim, in which the tamper evidencing element comprises an RFID device or an NFC device.
23. The tamper evident closure of any preceding claim, comprising a tamper evidencing ring or other indicator frangibly connected thereto and arranged to engage with the container when the closure is applied to the container.
24. The tamper evident closure of claim 23, wherein the tamper evidencing element and the tamper evidencing indicator each comprise a matching serial number.
25. The tamper evident closure of claim 23 or 24, wherein the tamper evidencing indicator comprises a tamper evidencing ring frangibly connected to the inner cap, or a tamper evidencing ring frangibly connected to the outer cap, or tamper evidencing rings connected to the inner cap and to the outer cap respectively.
26. The tamper evident closure of any preceding claim in which the tamper evidencing element is sandwiched between respective end walls of the inner cap and the outer cap.