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Patent Searching and Data


Title:
SNAP-ON CLOSURE
Document Type and Number:
WIPO Patent Application WO/2005/113361
Kind Code:
A1
Abstract:
A closure (30) for use, or in combination, with a member (10) defining an orifice, such as a container or fitment for attachment thereto, the closure comprising a first snap band formation (42) and the member comprising a second snap bead formation (18), the formations (18, 42) adapted to cooperate to provide a snap engagement retaining the closure with respect to the member while permitting at Least limited rotation with respect to the member. The closure further comprises a third ramped formation (44) interengageable with a fourth ramped formation (46) associated with the member upon the at least limited rotation, the interengagement of the third and fourth formations urging the closure to move axially away from the member and overcome the snap engagement. The third and fourth formations may be a recess and a projection. A tamper evident band may carry the fourth formation. The rotation may be permitted in one or both of clockwise and anticlockwise directions.

Inventors:
Mavin, Gerry (26 Home Farm Close, Ashington Northumberland NE63 8QX, GB)
Stephenson, Timothy (4 Castle Avenue, Rossington, Doncaster South Yorkshire DN11 0FF, GB)
Application Number:
PCT/GB2005/002009
Publication Date:
December 01, 2005
Filing Date:
May 23, 2005
Export Citation:
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Assignee:
PORTOLA PACKAGING LIMITED (3 Carriage Drive, White Rose Way, Doncaster South Yorkshire DN4 5NT, GB)
Mavin, Gerry (26 Home Farm Close, Ashington Northumberland NE63 8QX, GB)
Stephenson, Timothy (4 Castle Avenue, Rossington, Doncaster South Yorkshire DN11 0FF, GB)
International Classes:
B65D41/17; B65D41/47; B65D43/02; B65D47/06; (IPC1-7): B65D41/17; B65D41/47; B65D43/02; B65D47/06
Foreign References:
US3677431A1972-07-18
US6330959B12001-12-18
US4595111A1986-06-17
EP0603978A11994-06-29
US5865331A1999-02-02
US6095375A2000-08-01
Attorney, Agent or Firm:
Mcleish, Nicholas Alistair Maxwell (BOULT WADE TENNANT, Verulam Gardens 70 Gray's Inn Road, LONDON WC1X 8BT, GB)
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Claims:
CLAIMS :
1. A closure in combination with a member defining an orifice, the closure comprising a first formation and the member comprising a second formation, said first and second formations being adapted to cooperate to provide a snap engagement to retain the closure with respect to the member while at the same time permitting at least limited rotation with respect to the member, the closure further comprising a third formation interengageable with a fourth formation associated with the member upon said at least limited rotation of the closure with respect to the member, the interengagement of said third and fourth formations urging the closure to move axially away from the member and overcome the snap engagement provided by said first and second formations.
2. The combination of claim 1, wherein said member comprises a container.
3. The combination of claim 1, wherein said member comprises a fitment for attachment to a container, the container comprising an aperture and the orifice defined by the member being adapted to communicate with said aperture.
4. The combination of any preceding claim, wherein said first and second formations comprise a snap band and a snap bead.
5. The combination of any preceding claim, wherein said first and second formations lie in parallel radial planes with respect to an axis defined by said orifice.
6. The combination of claim 5, wherein upon interengagement of said third and fourth formations the planes defined by said first and second formations are caused to intersect.
7. The combination of claim 5 or claim 6 wherein, said third and fourth formations lie within a surface disposed substantially perpendicularly to the planes defined by said first and second formations.
8. The combination of any of claims 5 to 7, wherein said third and fourth formations comprise ramped surfaces which, when brought into interengagement upon said at least limited rotation of the closure with respect to the member, serve to direct a rotational force in a direction substantially perpendicular to the planes defined by said first and second formations.
9. The combination of any preceding claim, wherein said third and fourth formations comprise at least one pair of projections which are brought into engagement upon said at least limited rotation of the closure with respect to the member.
10. The combination of any of claims 1 to 8, wherein one of said third and fourth formations comprises a projection and the other of said third and fourth formations comprises a recess.
11. The combination of claim 10, wherein the projection is sized so as to be capable of receipt within the recess.
12. The combination of any preceding claim, wherein the third and fourth formations have a profile selected from the list comprising: arcuate, semi¬ circular, semielliptical, triangular, sawtooth, wedged, trapezoidal, or any combination thereof.
13. The combination of any preceding claim, wherein the third and fourth formations have symmetric profiles.
14. The combination of any of claims 1 to 12, wherein the third and fourth formations have asymmetric profiles.
15. The combination of any preceding claim, wherein said at least limited rotation may be effected in either of a clockwise or an anticlockwise direction.
16. The combination of any of claims 1 to 14, wherein said at least limited rotation may be effected in only one of a clockwise or an anticlockwise direction.
17. The combination of claim 16, wherein the third and fourth formations comprise rotationobstructing surfaces which, when brought into interengagemerit upon limited relative rotation between the closure and the member in a second direction opposite that of the direction of at least limited rotation, prevent further relative rotation between the closure and the member in that second direction.
18. The combination of claim 17, wherein further rotation of the closure in the second direction is transmitted to the member via the rotationobstructing surfaces to effect a corresponding rotation of the member in the second direction.
19. The combination of claim 18, wherein the member is arranged for screw engagement with a container, such engagement achievable when the member is placed over the container and the closure is rotated in the second direction.
20. The combination of any preceding claim, wherein the fourth formation is formed on said member.
21. The combination of any of claims 1 to 19, wherein the fourth formation is provided on a tamper evident indicator carried by said member.
22. The combination of claim 21, wherein said tamper evident indicator is provided with means interengageable with complementary means provided on said member to at least limit rotation of said tamper evident indicator with respect to said member such that said at least limited rotation of the closure with respect to the member does not effect a corresponding rotation of said fourth formation.
23. The combination of claim 21 or claim 22, wherein said tamper evident indicator is frangibly connected to the closure and engageable with the member upon said snap engagement of said first and second formations.
24. The combination of claim 23, wherein the frangible connection with which the tamper evident indicator is joined to the closure is adapted to rupture as the closure is rotated with respect to said member and before the snap engagement provided by said first and second formations is overcome.
25. The combination of claim 23 or claim 24, wherein the tamper evident indicator is adapted to be retained on the member after rupture of the frangible connection with which the tamper evident indicator is joined to the closure.
26. The combination of any of claims 23 to 25, wherein, upon initial interengagement of the third and fourth formations, the tamper evident indicator is urged axialIy away from the closure and into engagement with the member.
27. The combination of claim 26, wherein the tamper evident indicator constitutes a drop down indicator such that after the snap engagement provided by said first and second formations has been overcome and the closure is reapplied to the member the tamper evident indicator remains spaced apart from the closure.
28. The combination of any of claims 23 to 27, wherein the member is provided with an annular channel in which to at least partially receive the tamper evident indicator.
29. A closure for use with a member defining an orifice, the closure comprising a cap having a first formation adapted to cooperate with a second complementary formation provided on the member to provide a snap engagement to retain the cap with respect to the member while at the same time permitting at least limited rotation with respect to the member; and a tamper evident indicator frangibly connected to the cap and provided with means interengageable with complementary means provided on the member to at least limit rotation of the tamper evident indicator with respect to the member once said snap engagement has been established such that said at least limited rotation of the cap with respect to the member does not effect a corresponding rotation of the tamper evident indictor, the cap comprising a third formation and the tamper evident indicator comprising a fourth formation such that, upon said at least limited rotation of the cap with respect to the member, the frangible connection between the tamper evident indicator and the cap breaks allowing the third formation to engage the fourth formation and urge the cap axialIy away from the member and overcome the snap engagement provided by said first and second formations.
30. The closure of claim 29, wherein said member comprises a container.
31. The closure of claim 29, wherein said member comprises a fitment for attachment to a container, the container comprising an aperture and the orifice defined by the member being adapted to communicate with said aperture.
32. The closure of any of claims 29 to 31, wherein said first and second formations comprise a snap band and a snap bead.
33. The closure of any of claims 29 to 32, wherein said first and second formations lie in parallel radial planes with respect to an axis defined by said orifice.
34. The closure of claim 33, wherein upon interengagement of said third and fourth formations the planes defined by said first and second formations are caused to intersect.
35. The closure of claim 33 or claim 34, wherein said third and fourth formations lie within a surface disposed substantially perpendicularly to the planes defined by said first and second formations.
36. The closure of any of claims 33 to 35, wherein said third and fourth formations comprise ramped surfaces which, when brought into interengagement upon said at least limited rotation of the cap with respect to the member, serve to direct a rotational force in a direction substantially perpendicular to the planes defined by said first and second formations.
37. The closure of any of claims 29 to 36, wherein said third and fourth formations comprise at least one pair of projections which are brought into engagement upon said at least limited rotation of the cap with respect to the member.
38. The closure of any of claims 29 to 37, wherein one of said third and fourth formations comprises a projection and the other of said third and fourth formations comprises a recess.
39. The closure of claim 38, wherein the projection is sized so as to be capable of receipt within the recess.
40. The closure of any of claims 29 to 39, wherein the third and fourth formations have a profile selected from the list comprising: arcuate, semi¬ circular, semielliptical, triangular, sawtooth, wedged, trapezoidal, or any combination thereof.
41. The closure of any of claims 29 to 40, wherein the third and fourth formations have symmetric profiles.
42. The closure of any of claims 29 to 40, wherein the third and fourth formations have asymmetric profiles.
43. The closure of any of claims 29 to 42, wherein said at least limited rotation may be effected in either of a clockwise or an anticlockwise direction.
44. The closure of any of claims 29 to 42, wherein said at least limited rotation may be effected in only one of a clockwise or an anticlockwise direction.
45. The combination of claim 44, wherein the third and fourth formations comprise rotationobstructing surfaces which, when brought into interengagement upon limited relative rotation between the closure and the member in a second direction opposite that of the direction of at least limited rotation, prevent further relative rotation between the closure and the member in that second direction.
46. The combination of claim 45, wherein further rotation of the closure in the second direction is transmitted to the member via the rotationobstructing surfaces to effect a corresponding rotation of the member in the second direction.
47. The combination of claim 46, wherein the member is arranged for screw engagement with a container, such engagement achievable when the member is placed over the container and the closure is rotated in the second direction.
48. The closure of any of claims 29 to 47, wherein the frangible connection with which the tamper evident indicator is joined to the cap is adapted to rupture as the cap is rotated with respect to said member and before the snap engagement provided by said first and second formations is overcome.
49. The closure of any of claims 23 to 48, wherein the tamper evident indicator is adapted to be retained on the member after rupture of the frangible connection with which the tamper evident indicator is joined to the cap.
50. The closure of any of claims 29 to 49, wherein, upon initial interengagement of the third and fourth formations, the tamper evident indicator is urged axialIy away from the cap and into engagement with the member.
51. The closure of any of claims 29 to 50, wherein the tamper evident indicator constitutes a drop down indicator such that after the snap engagement provided by said first and second formations has been overcome and the cap is reapplied to the member the tamper evident indicator remains spaced apart from the cap.
52. A closure in combination with a member defining orifice, the closure comprising a first formation and the member comprising a second formation, said first and second formations being adapted to cooperate to provide a snap engagement to retain the closure with respect to the member while at the same time providing at least limited rotation with respect to the member, a path described by said first formation upon said at least limited rotation intersecting said second formation at one or more locations to permit the closure to disengage from the member.
53. A closure in combination with a member defining an orifice, the combination being substantially as herein described with reference to Figures 2 to 10 of the accompanying drawings.
54. A closure for use with a member defining an orifice, the closure being substantially as herein described with reference to Figures 2 to 10 of the accompanying drawings.
55. A member defining an orifice, the member being substantially as herein described with reference to Figures 2 to 10 of the accompanying drawings. 229904.
Description:
SNAP-ON CLOSURE

The present invention relates to snap-on closures. Snap-on closures are well known. Snap-on closures are typically provided with a circumferential snap band which is arranged for complementary engagement with a circumferential snap bead provided around the neck of a container. The closure may be applied to the container by urging the closure downwards onto the neck so that the snap band on the closure snaps over and into engagement with the snap bead on the neck. In order to remove the closure, the snap band of the closure must overcome the snap bead of the container neck. This may be achieved by flexing the closure with respect to the container neck. Consequently, known snap-on closures are generally flexible or pliable. In addition, snap-on closures are preferably able to be flexed relatively easily by both children and elderly users, who may lack the manual dexterity and strength of the rest of the population. The seal obtainable with known snap- on closures is therefore not particularly good, since the closures cannot engage the container necks very tightly if they are to be opened by a cross-section of the population. This presents a number of problems including an inferior seal and a poor tamper evidencing capability. In other words, where a closure having such an inherently weak seal is provided with a tamper evident (TE) band frangibly connected to the closure, it is often possible to so flex the closure as to be able to remove the closure from the container without breaking the frangible bridges between the closure and the TE band, thereby enabling the TE band to be removed intact. Under such circumstances it is possible to interfere with the contents of the container and defeat the tamper evidencing mechanism by removing and subsequently replacing both the cap and the TE band. In view of the problems associated with snap-on closures, the packaging industry has generally moved away from snap-on closures and concentrated instead on threaded or screw-on closures. However, there are a number of further problems associated with threaded closures. Firstly, threaded closures are more complex. Secondly, there has been a trend in recent years within the packaging industry towards full, wrap¬ around graphics which are directly printed onto the outside of containers, instead of the traditional printing of labels which are then affixed to the containers. Following the printing of the graphics, a container is filled and a closure is then applied to form a sealed package. However, the application of a threaded closure to the container requires the outside of the container to be gripped to hold it securely in place while the closure is rotated onto the neck. Such a gripping of the container can spoil or otherwise damage the graphics and is therefore undesirable for manufacturers. Furthermore, the direct printing of the graphics may represent a significant proportion of the cost of manufacturing the containers. Accordingly anything that risks spoiling the graphics in this way may not only be wasteful but may also be expensive. Thirdly, threaded closures are not suitable for use with certain kinds of containers. In particular, containers which are intended to be used in a microwave oven. This is because the lid of such a container must be able to disengage, or "pop" off the container to prevent an explosion in the microwave should the pressure inside the container become too great . Attempts have been made to overcome the above problems, but these present still other problems. For example, Figures Ia and Ib show a prior art container 1 and a snap-on lid 2. The container 1 has an annular wall 3, which runs circumferentially around the outside of the container just below a snap bead 4 which is also provided on an external surface of the container. An example of such a container and lid are the UNI-5102-White and UNI-2900-White, from the UNIPAK range manufactured by Ashwood Timber & Plastics Limited, of London, United Kingdom. Between the annular wall 3 and the external surface of the container 1 there is formed an annular trough 5 in which a lower rim 6 of the lid 2 sits when the lid is applied to the container. When the annular wall 3 runs uninterrupted around the full circumference of the container 1 - thereby entirely covering the lower rim 6 of the lid 2 - a user is not able to manipulate any portion of the lid in order to snap the lid off the container. This arrangement is shown in Figure Ia. However, the annular wall 3 is provided with a pair of hinged tabs 7 (only one of which is illustrated) . The non-hinged sides of the tabs 7 are initially frangibly connected (as indicated by reference numeral 8 in Figure Ia) to the remainder of the annular wall 3 to form an uninterrupted whole. In use, one or both of the tabs 7 may be broken away from the annular wall 3 and opened out to expose a portion of the lower rim 6 of the lid 2. The lid 2 may then be lifted to remove the lid from the container 1. This arrangement is shown in Figure Ib. However, the or each opened tab 7 then presents an unattractive protrusion on the container 1. In addition, parts of the tab 7 or annular wall 3 may be left with sharp edges or projections once the tab has been broken away from the annular wall and these are clearly undesirable. Furthermore, the provision of the annular wall 3 increases manufacturing costs and complexity, and results in an overall larger container for the same internal capacity. There is a need, therefore, for an improved closure. In particular, it would be desirable for the closure to be capable of realising a relatively tight engagement with a container in order to provide enhanced sealing characteristics. It would also be desirable for the closure to be readily removable from, and re-applicable to, the container by users of varying strength and dexterity. In addition, it would be desirable for the closure to exhibit a good tamper evidencing capability. It would also be desirable for the closure to be suitable for use with containers of potable fluids and foodstuffs that are intended to be heated in a microwave oven. Finally, it would be desirable for the closure to be capable of being fitted to a container without the requirement to grip or hold the outside of the container in such a way as might risk damaging any graphics printed on it. The present invention aims to address the above and other objectives by providing an improved closure. According to a first aspect of the present invention, there is provided a closure in combination with a member defining an orifice, the closure comprising a first formation and the member comprising a second formation, said first and second formations being adapted to cooperate to provide a snap engagement to retain the closure with respect to the member while at the same time permitting at least limited rotation with respect to the member, the closure further comprising a third formation interengageable with a fourth formation associated with the member upon said at least limited rotation of the closure with respect to the member, the interengagement of said third and fourth formations urging the closure to move axially away from the member and overcome the snap engagement provided by said first and second formations. With the combination of the present invention, it is not necessary for a user to manually flex the closure upwardly to overcome the snap engagement and so remove the closure from the container. As a result, weakening or fatigue of the closure over time may be advantageously avoided. This helps to maintain a reliable seal between the closure and the container. In addition, the seal provided by the combination of the present invention may be tighter than with previous snap-on closures. Because it is not necessary for a user to flex the closure upwardly to open the closure, the closure may have a more rigid structure, thereby enabling a tight seal to be achieved both before a container has been opened for the first time and on subsequent use. Furthermore, the mechanism for removing the closure is relatively straightforward and simple. Thus users of varying manual strength and dexterity may operate the closure with confidence. In one preferred embodiment a user simply rotates the closure with respect to the container to bring the third and fourth formations into interengagement . Upon such interengagement, the closure is forced axially away from the container, typically in an upward direction, and the snap engagement provided by the first and second formations is overcome. The closure may then simply be lifted off the container to gain access to the packaged product. Interengagement of the third and fourth formations - effected by relative rotation of the closure and container - causes the closure to move axially away from the container. As will be understood, therefore, a rotational motion imparted to the closure by a user is transformed into a generally linear motion by the interaction of the third and fourth formations. Preferably, this linear motion is in a direction generally parallel to the axis of rotation of the closure. More preferably still, the linear motion is in a direction substantially collinear with the axis of rotation. The third and fourth formations interact to provide a lifting or "cam" engagement. Preferably, therefore, one of the third and fourth formations has a projecting or "bump" profile while the other of the third and fourth formations has a complementary, recessed profile which is sized to accept the first profile. In preferred embodiments, the closure also comprises a TE band frangibly connected to the closure. Embodiments of the present invention are able to provide a more enhanced tamper evidencing capability than the snap-on closures of the prior art by providing frangible connections between the closure and the TE band that are more delicate. This is possible because the snap engagement provided by the first and second formations may be tighter than before. As a result the closure may be reliably held in place by the interengagement of the first and second formations alone and does not need to rely on the TE band for assistance. The function of the TE band - to provide a tamper evidencing capability - may therefore be optimised, by removing its closure- retention role and using the TE band solely for its primary purpose. Advantageously, embodiments of the present invention are suitable for use with containers of varying shape, size and function. In particular, embodiments of the present invention may be used to package potable fluids and foodstuffs that are intended to be heated in a microwave oven. Furthermore, the closure of the present invention may be fitted to a container without the need to grip the outside of the container and risk spoiling any graphics which may have been printed on it. According to a second aspect of the present invention, there is provided a closure for use with a member defining an orifice, the closure comprising a cap having a first formation adapted to cooperate with a second complementary formation provided on the member to provide a snap engagement to retain the cap with respect to the member while at the same time permitting at least limited rotation with respect to the member; and a tamper evident indicator frangibly connected to the cap and provided with means interengageable with complementary means provided on the member to at least limit rotation of the tamper evident indicator with respect to the member once said snap engagement has been established such that said at least limited rotation of the cap with respect to the member does not effect a corresponding rotation of the tamper evident indictor, the cap comprising a third formation and the tamper evident indicator comprising a fourth formation such that, upon said at least limited rotation of the cap with respect to the member, the frangible connection between the tamper evident indicator and the cap breaks allowing the third formation to engage the fourth formation and urge the cap axialIy away from the member and overcome the snap engagement provided by said first and second formations. Other preferred features are set out in the accompanying description and in the claims which are appended thereto. The present invention may be put into practice in a number of ways and some embodiments will now be described, by way of example only, with reference to the accompanying drawings in which: Figures Ia and Ib show a prior art container and snap-on lid; Figure 2 shows a closure and spout member in accordance with a first embodiment of the present invention; Figures 3a and 3b show the closure and spout member of Figure 2 before and after snap-on engagement; Figures 4a and 4b show the closure and spout member of Figure 2 upon limited rotation of the closure and following disengagement; Figure 5 shows a closure in accordance with a second embodiment of the present invention; Figure 6 shows a section of the closure of Figure 5, when applied to a container; Figure 7 shows a food storage container and closure, in accordance with a third embodiment of the present invention; Figure 8 shows, schematically, a closure and container neck in accordance with a further embodiment of the present invention; Figure 9 shows, schematically, a closure and container neck in accordance with still a further embodiment of the present invention; and Figure 10 shows, schematically, a snap band and snap bead arrangement in accordance with yet another embodiment of the present invention. Referring to Figure 2, there is shown a spout member 10 and a closure 30 which is arranged to engage the spout member 10. In this specification, the term "closure" is used to denote an item which closes or covers an orifice and therefore includes caps, overcaps, tops, lids (dust) covers and other items, which may or may not comprise additional components, such as tamper evident bands. The spout member 10 has a dispensing spout 12 which defines an opening 13 through which a fluid or flowable product may be discharged from a container (not shown) to which the spout member is fitted. In the embodiment shown, the dispensing spout 12 has a generally frustoconical shape although, of course, the dispensing spout may take any of various forms. At an end remote from the opening 13, the dispensing spout 12 merges with a generally radially outwardly extending shoulder 14. The shoulder 14, in turn, merges with a generally downwardly depending external wall 16. Disposed about an outer circumference of the generally radially outwardly extending shoulder 14, at the junction between the shoulder and the generally downwardly depending external wall 16, is a snap bead formation 18, which provides a radially outwardly extending, flange-like ridge. The snap bead 18 is arranged to provide snap engagement with a complementary engagement means provided on the closure 30, as discussed in more detail below. In the example shown, the snap bead 18 extends around the whole of the periphery of the shoulder 14. However, the snap bead 18 may alternatively be interrupted and so provided only at spaced intervals around the shoulder 14. At an opposite, lower end of the generally downwardly depending external wall 16, the wall merges with a further radially outwardly extending shoulder 20. Anti-rotation lugs 22 are provided at the junction between the generally downwardly depending external wall 16 and the second shoulder 20. In Figure 2, the anti-rotation lugs 22 are arranged uniformly around the entirety of the second shoulder 20. It will be appreciated, however, that the number and the position of the lugs 22 may be subject to considerable variation. As will be understood, the spout member 10 is arranged for complementary engagement with a neck portion (not shown) of a container (also not shown) . The remainder of the spout member 10 is designed to achieve this engagement. The second radially outwardly extending shoulder 20 merges at an outer edge with a knurled downwardly depending external wall 24, which may be gripped by a user to remove the spout member 10 from the neck portion of the container. At a lower end of the knurled wall 24, the spout member 10 comprises an annular rim 26, to which is connected a tamper evident (TE) band 28 by means of several frangible bridges 2.9. The knurled wall 24 is provided on an internal surface with engagement means (not shown) , typically in the form of a helical screw thread, to permit the spout member 10 to be fixed onto the neck portion of the container. By contrast, the TE band 28 is provided on an internal surface with anti-rotation means (also not shown) so that, upon engagement of the spout member 10 with the neck portion of the container, rotation of the spout member in a direction tending to remove it from the neck portion causes the frangible bridges 29 to break since corresponding rotation of the TE band is prevented. To this end the anti-rotation means provided on the TE band are adapted to engage with complementary anti- rotation means disposed on the neck portion (again, not shown) . The closure 30 comprises a generally dome-shaped cap member 32 which is connected to a tamper evident (TE) skirt 34 by means of a number of frangible bridges 36. The frangible bridges 36 are connected between a lower rim 38 of the cap member 32 and an upper rim 40 of the TE skirt 34. The lower and upper rims 38, 40 are both generally horizontal. That is, when the closure 30 is applied to the spout member 10, the greater part of both runs in radial planes. Furthermore, both lower and upper rims 38, 40 are substantially annular in shape such that, when the cap member 32 and TE skirt 34 are connected together, the lower and upper rims are arranged substantially adjacent and parallel with each other. The cap member 32 is provided with a snap engagement means in the form of a snap band 42 which is arranged for complementary engagement with the snap bead 18 on the spout member 10. The snap band 42 is disposed circumferentially around the lower rim 38 of the cap member 32 and arranged to extend radially inwardly from the lower rim. As shown in Figure 2, the snap band 42 does not extend without interruption around the inner circumference of the lower rim 38. This is because the lower rim 38 comprises first and second recessed portions 44. The recessed portions 44 are arcuate and are formed in the surface of the cap member 32. As such, the lower rim 38 of the cap member 32 comprises two diametrically opposed, major arcuate regions which lie in the same radial plane and two diametrically opposed, minor arcuate regions which lie in different surfaces and which are normal to the radial plane. , The major arcuate regions together form the greater part of the circumference of the lower rim 38 of the cap member 32 and it is around these parts of the circumference that the snap band 42 extends on an inner surface of the cap member. However, the snap band 42 does not extend into the regions of the cap member 32 which comprise the recessed portions 44. The TE skirt 34 is provided on the upper skirt rim 40 with first and second projecting, or bump portions 46. The projecting portions 46 are shaped and sized so as to complement the recessed portions 44 provided in the cap member 32 so that, when the frangible bridges 29 are in tact, the lower rim 38 of the cap member 32 may be uniformly spaced from and extend substantially parallel to the upper rim 40 of the TE skirt 34. That is, each recessed portion 44 is configured to receive and accept one of the projecting portions 46. Thus, like the lower rim 38 of the cap member 32, the upper rim 40 of the TE skirt 34 comprises two diametrically opposed, major arcuate regions which lie within the same, radial plane and two diametrically opposed, minor arcuate regions which lie within different surfaces and which are normal to the radial plane. An inner surface of the TE skirt 34 may be shaped adjacent the upper rim 40 to engage the snap bead 18 of the spout member 10 so that the TE skirt 34 is retained on the spout member once the frangible bridges 36 have been broken. A TE snap band 48 may be provided to perform this function. The TE snap band 48 need not run around the entire inner circumference of the TE skirt 34. Instead, it may simply be provided on an inner surface of the or each projecting portion 46. Likewise, the TE snap band 48 need not extend radially inwards to the same extent as the snap band 42 provided on the cap member 32. However, since the closure 30, at least initially, comprises both the cap member 32 and the TE skirt 34, it is preferable for the internal diameters of the lower rim 38 and the upper rim 40 to be substantially equal. In this way uniform snap engagement with the snap bead 18 of the spout member 10 may be obtained for both the cap member and the TE skirt. However, it is not necessary for this to be the case and variations in the respective diameters which still provide the desired snap engagement are envisaged. Finally, the TE skirt 34 is provided with anti- rotation lugs 50 which are disposed on an inner surface of the TE skirt. The anti-rotation lugs 50 are arranged for complementary engagement with the anti-rotation lugs 22 provided on the second shoulder 20 of the spout member 10. The process of applying the closure 30 to, and removing it from, the spout member 10 will now be described with reference to Figures 3a to 4b. The first time the closure 30 is placed onto the spout member 10, the cap member 32 and the TE skirt 34 are connected together by the frangible bridges 36, as shown in Figure 3a. The closure 30 is positioned co- axially above the spout member 10, so that, in plan view, the snap band 42 of the cap member and the snap bead 18 of the spout member are substantially concentric. In other words, a central axis (A) of the closure 30 is generally coaxial with a central axis (B) of the spout member 10. The central axis (A) of the closure 30 may be defined by a line passing through the respective centres of the dome-shaped cap member 32 and the generally annular TE skirt 34. Similarly, the central axis (B) of the spout member 10 may be defined by a line passing through the respective centres of the radially outwardly extending shoulders 14 and 20 and the generally downwardly depending external wall 16. The line may also pass through a centre of the dispensing spout 12, although in some embodiments the dispensing spout may be located eccentrically on the spout member 10. Alternatively, the central axes (A) and (B) may be defined by lines which pass normally through the centres of the planar surfaces enclosed by the snap band 42 and the snap bead 18, respectively. In many embodiments of the present invention - including the embodiment illustrated in Figures 1 to 4b - the line passing normally through the centre of the planar surface enclosed by the snap band 42 is collinear with the line passing through the centres of the cap member 32 and the TE skirt 34, and this is preferred. The closure 30 is urged axially downwards onto the spout member 10, as indicated by the two arrows in Figure 3a. During this step, a lower rim 52 of the TE skirt 34 is guided past the dispensing spout 12 and the snap bead 18. It will be understood, therefore, that the internal diameter of the lower rim 52 of the TE skirt is greater than the outer diameter of the snap bead 18, so that the downward motion of the lower rim is not impeded or obstructed by the snap bead. In fact, in the embodiment shown, the internal diameter of the lower rim 52 of the TE skirt is also greater than the diametrical distance between the radially- outer surfaces of two diametrically opposed anti- rotation lugs 22. In this way, the lower rim 52 may also pass unhindered over the anti-rotation lugs 22 and into confrontation with the second radially outwardly extending shoulder 20 of the spout member 10. At this point, no further downward motion of the closure 30 is permitted because the outer diameter of the shoulder 20 is greater than the internal diameter of the lower rim 52 so that the lower rim may not pass over the shoulder. Although the lower rim 52 of the TE skirt 34 is not obstructed or hindered by any part of the spout member 10 before reaching the second shoulder 20, other parts of the closure 30 are. Namely, the snap band 42 provided on the cap member 32 and the TE snap band 48 provided on the TE skirt 34, both of which are urged into engagement with the snap bead 18 provided on the spout member before the closure 30 reaches its lowest point on the spout member 10. The following discussion will concentrate on the snap band 42 of the cap member 32, although it will be understood that similar considerations apply to the TE snap band 48 provided on the TE skirt 34. The internal diameter of the snap band 42 provided on the closure 30 lies within a range of values between substantially equal to the diameter of the generally downwardly depending external wall 16 and substantially equal to the external diameter of the snap bead 18. As such, once the closure 30 has been applied to the spout member 10, the snap band 42 should not be under excessive tension as a result of being stretched around the generally downwardly depending external wall 16 by virtue of having a significantly smaller diameter. Such stretching may weaken the seal obtainable with the closure 30 over time while the small diameter may initially make fitting and removal of the closure difficult. At the same time, the snap band 42 should not have a diameter larger than the external diameter of the snap bead 18; otherwise, there will be no snap engagement. Preferably, as shown in Figure 3a, the snap bead 18 is provided with a bevel, cant or radially outwardly and downwardly sloping surface 19a which terminates and merges with a generally horizontal shoulder 19b. The inner diameter of the bevel 19a is preferably slightly less than or substantially equal to the internal diameter of the snap band 42 and is therefore substantially the same as the external diameter of the generally downwardly depending external wall 16. In this way, the snap bead 18 may initially serve as a guide seat for the closure 30, helping direct the snap band 42 axially downwards and into snap engagement with the horizontal shoulder 19b. As the closure 30 is urged downwards onto the spout member 10, the bevel 19a of the snap bead 18 causes the snap band 42 to stretch outwardly to accommodate its increasing diameter. As a result, when the snap band 42 passes over the snap bead 18 to a position adjacent the generally downwardly depending external wall 16, the snap band returns to its unstretched state and snaps into engagement with the snap bead. This step is shown schematically in Figure 3b by the dashed lines on either side of the closure 30 in the region of the snap band 42 and snap bead 18. Figure 3b shows the arrangement in which the closure 30 has been applied to and engages with the spout member 10. Upon the snap engagement of the closure 30 and the spout member 10, the respective sets of anti- rotation lugs 22, 50 are also brought into intermeshing engagement. Although not shown, the cap member 32 may be provided on an internal surface with an annular plug, the plug being sized and positioned to form a seal with the spout opening 14 when the closure 30 and spout member 10 are assembled together. As shown in Figure 3b, a rotation of the cap member 32 will cause a corresponding rotation of the TE skirt 34 since the two are interconnected by the frangible bridges 36. However, in the assembled arrangement shown in Figure 3b, rotation of the TE skirt 34 is constrained by the anti-rotation lugs 22, 50. Such constraint may be total in the case where the lugs 22, 50 are arranged so that, once intermeshed, no relative movement of them is possible. Preferably, however, the constraint is not total so that a limited degree of rotation of the TE skirt 34 is possible, for example, between approximately 5-10°. This reduces the precision required when applying the closure 30 to the spout member 10, since the anti- rotation lugs 22, 50 do not have to be perfectly aligned for intermeshing engagement. Therefore, upon initial rotation of the closure 30, which may be effected by gripping and turning the cap member 32, the cap member and the TE skirt 34 rotate together until the anti-rotation lugs 22, 50 are brought into mutual engagement. From this point, no further rotation of the TE skirt 34 is possible in the same direction. A further, limited rotation of the cap member 32 therefore causes the frangible bridges 36 to be broken, separating the cap member from the TE skirt 34 and giving evidence of tampering or opening of the container to which the spout member 10 is assembled. During this further limited rotation, a first rising part 45 of the recessed portion 44 on the cap member 32 rotates towards the projecting portion 46 on the constrained TE skirt 34 and into confrontation with a second rising part 47. This arrangement is shown in Figure 4a. Throughout this limited rotation of the closure 30 with respect to the spout member 10, the snap band 42 of the cap member 32 remains in snap engagement with the snap bead 18 of the spout member. Accordingly, the snap member 32 may be rotated in the opposite direction if so desired and through the same angle which brought the closure from the position shown in Figure 3b to that shown in Figure 4a and the integrity of the closure's seal would not be compromised. In fact, in the embodiment shown, the cap member 32 could be rotated in the opposite direction through twice the angle of rotation effected in the first direction, while still maintaining the integrity of the seal. However, in that case-, instead of the left-hand rising parts 45 and 47 being in initial interengagement, right-hand rising parts 45 and 47a would be in confrontation. As shown in Figure 4a, further rotation of the cap member 32 cannot take place while maintaining the previous vertical separation or clearance between the upper rim 40 of- the TE skirt 34 and the lower rim 38 of the cap member. Up to this point, the two rims 38, 40 have remained generally parallel and adjacent one another. However, upon further rotation of the cap member 32, interengagement between the rising part 45 of the recessed portion 44 and the rising part 47 of the projecting portion 46 causes the cap member to move axially upwards and away from the TE skirt 34. As this takes place, the snap band 42 of the cap member 32 is brought up into confrontation with the generally horizontal shoulder 19b of the snap bead 18 on the spout member 10. Generally, the force required to enable all points along the snap band 42 to simultaneously overcome the snap bead 18 is such as to prevent removal of the cap member. All that would happen is that a user's fingers gripping the cap member 32 and pulling in an upwards direction would slide off as the applied upward force was increased. However, upon interengagement of the recessed portion 44 and the projecting portion 46, only the region of the snap band 42 adjacent the rising part 45 is forced increasingly against the snap bead 18 as the cap member is rotated. Accordingly, it is not the entire circumference of the lower rim 38 of the cap member which needs to be temporarily deformed in order for the snap band 42 to overcome the snap bead 18, but rather that specific region of the lower rim which trails the recessed portion 44 in the direction of rotation. This region of the lower rim 38, being urged upwards by the interengagement of the recessed and projecting portions 44, 46, temporarily deforms and thus permits the associated region of the snap band 42 to overcome the snap bead 18 and become disengaged thereform. Then, upon continued rotation of the cap member 32, the remainder of the snap band 42 lying below the snap bead 18 is urged in consecutive sequence to overcome the snap bead so that ultimately the cap member may be disengaged and be removed from the spout member. This arrangement is shown in Figure 4b. Thus, in summary, with the closure 30 applied to the spout member 10, the closure may nonetheless be rotated relative to the spout member. This rotation however, causes the frangible bridges 36 between the closure's cap member 32 and TE skirt 34 to break. Then, upon interengagement of the recessed and projecting portions 44, 46, the closure 30 is urged axially away from the spout member 10 - leaving the TE skirt 34 behind - so that the snap-on engagement provided by the snap band 42 and the snap bead 44 is overcome and enabling the closure to be removed from the spout member. The closure 30 - now comprising only the cap member 32 - may be replaced on the spout member 10 by urging the closure axially downwards, back over and into engagement with the snap bead 18, ensuring that the recessed portions 44 are in alignment with and received by the projecting portions 46. A resealable, snap-on closure is thereby provided. In some embodiments, the order of the steps may not be exactly as described above. For example, the frangible bridges 36 may not break before the interengagement of the recessed and projecting portions 44, 46 causes the closure 30 to be lifted away from the spout member 10. In fact, it may be that the lifting helps to break the bridges 36 as well as overcome the snap engagement. Also, as will be apparent, in embodiments having more than two complementary recessed and projecting portions 44, 46, the amount of relative rotation required to derail and disengage the snap band 42 from the snap bead 18 is correspondingly reduced. Having said that, the more complementary recessed and projecting portions 44, 46 there are, the more parts of the snap band 42 there are which need to be simultaneously forced to disengage with the snap bead 18. Accordingly, more force is actually required to rotate the closure 30, even though the closure does not need to be rotated through so great an angle. As a consequence, providing more complementary recessed and projecting portions 44, 46 does not necessarily make removing the closure 30 easier. One or two complementary recessed and projecting portions 44, 46 is therefore preferred, as it is easier to derail the snap band 42 at fewer points and easier to align fewer recessed and projecting portions upon reapplication of the closure. The above embodiment relates to a closure 30 which has a domed shape and is adapted for snap-on engagement with a spout member 10 and it is the spout member that is adapted to be affixed to a container. In another embodiment, the closure 30 is adapted to form a snap seal with the container itself. Accordingly it will be understood that parts of the spout member 10 which provide the snap engagement, anti-rotation and downward motion obstruction functions may be equivalently transferred to the container. The recessed and projecting portions 44, 46 shown in Figures 2 to 4b have a generally arcuate profile, which provide lifting surfaces for disengagement of the snap band 42 from the snap bead 18. The profile of the recessed and projecting portions 44, 46 may, however, take any form suitable for providing the disengagement. For example, the profile may be arcuate, semi-circular, semi-elliptical, triangular, saw-tooth, wedged, trapezoidal or may be any suitable combination of the above. The profiles may, in addition, be either symmetrical or asymmetrical, depending on the desired performance of the disengagement mechanism. In the embodiment described above, the symmetrical nature of recessed and projecting portions means that the closure 30 can be rotated in either of a clockwise direction or an anti¬ clockwise direction to remove the closure 30. However, instead of being bidirectional, the disengagement mechanism may alternatively be unidirectional, so that the closure 30 may only be rotated in one of a clockwise or anti-clockwise direction to effect disengagement of the snap bead and snap band. In the latter case, rotation of the closure 30 may be constrained to that one direction by providing the profile of the recessed and projecting portions 44, 46 with a lifting surface and a rotation- obstructing surface, for example, a wedged or saw- tooth profile. In the first embodiment described above, when the lower rim 52 of the TE skirt is in contact with the second shoulder 20 of the spout member 10, the snap band 42 of the cap member 32 is relatively close to . the snap bead 18. This means that when the closure 30 is first removed from the spout member 10, the step of breaking the frangible bridges 36 occurs only shortly before the snap band 42 is brought into disengaging confrontation with the snap bead 18. In some embodiments, the configuration of the TE skirt 34 and the generally downwardly depending external wall 16 may be such that these steps take place substantially simultaneously. However, it will be appreciated that there will be a relatively greater instantaneous force required at that moment, both to break the frangible bridges 36 and to overcome the snap engagement. In one embodiment, therefore, the vertical height of the generally downwardly depending external wall 16 is increased. As a result, when the closure 30 is initially applied to the spout member 10 (or to the container neck) , the lower rim 52 of the TE skirt 34 does not rest on the second shoulder 20, but lies slightly above it. As described above, interengagement of the recessed and projecting portions 44, 46 - effected by relative rotation of the cap member 32 with respect to the TE skirt 34 - urges the cap member and the TE skirt axially apart. Because previously the lower rim 52 of the TE skirt 34 was in contact with the second shoulder 20, this axial separation resulted in the cap member 32 moving upwards and away from the TE skirt. However, in the present embodiment, the lower rim 52 is not initially in contact with the second shoulder 20. Therefore, upon rotation of the closure 30 with respect to the spout member 10 (or the container neck) , once the recessed and projecting portions 44, 46 interengage, it is the TE skirt 34 which moves axialIy away from the cap member 32. Thus the TE skirt 34 is urged axially downwards while the closure 30 remains in snap engagement with the snap bead 18, thereby breaking the frangible bridges 36 between the TE skirt and the cap member 32. This downward motion continues until the TE skirt 34 comes into contact with the second shoulder 20 and further downward motion is stopped. Further rotation of the cap member 32, and further interengagement of the recessed and projecting portions 44, 46, therefore causes the cap member to move upwards away from the TE skirt with the result that the snap engagement is overcome in a similar manner to that already described. In this embodiment, it is ensured that the steps of breaking the frangible bridges 36 and overcoming the snap engagement take place at different times, thereby reducing the maximum instantaneous force required during opening. Another advantage of this embodiment is that, once separated from the cap member, the TE skirt drops down away from the snap bead 18 and so provides a clear indication of tampering. However, it is preferable to increase at least the vertical height of the recessed and projecting portions 44, 46 in view of the increased distance between the second shoulder 20 and the snap bead 18. Of course, since the. recessed and projecting portions 44, 46 are complementary it does not matter which of the recessed and projecting portions is provided on which of the closure or spout member or, indeed, container neck. That is, where a recessed portion 44 has been described in relation to a first member and a projecting portion 46 has been described in relation to a second member, the recessed and projecting portions may be interchanged. In either case, the interengagement of the recessed and projecting portions 44, 46 provides the ramping mechanism required to overcome the snap engagement . Although Figures 2 to 4b illustrate an embodiment comprising a spout member 10 and a closure 30 having a domed cap member 32, any suitable form of closure may be used. For example, Figure 5 shows an embodiment of the present invention in which the closure 30 comprises a substantially flat cap 60. The cap 60 is provided with manual gripping means in the form of knurls 62 to assist in rotation of the closure 30. Figure 6 shows, in cross-section, the closure 30 of Figure 5 applied to the neck 70 of a container 80. As shown, the container neck 70 has a neck stretch portion 72 on which is disposed the bevelled snap bead 18 and the anti-rotation lugs 50. In this embodiment, an upper, generally horizontal surface 51 of each of the anti-rotation lugs 50 provides the resistance to the downward movement of the TE skirt that was provided by the second generally horizontal, radially outwardly extending shoulder 20 in previous embodiments. What is more, it is not the engagement of this surface by the lower rim 52 of the TE skirt 34 which limits the downward movement of the TE skirt but a lower surface of a radially inwardly extending, annular rim 54 formed at an upper end of the TE skirt. An annular wall 74 is provided externally and circumferentially around the container neck 70. The annular wall 74 merges with a radial flange 76 towards a lower end and it is by this flange that the annular wall 74 is joined to the neck stretch portion 72. The annular wall 74 is provided as a further tamper evidencing safeguard as it serves to receive the TE skirt 34 within the annular channel formed between the annular wall and the neck stretch portion and so prevents attempts to interfere with the TE skirt. The annular wall 74 also serves to hide the anti-rotation lugs 22. The cap 60 of the closure 30 comprises a generally annular plug 64 which serves to form a seal between an opening of the container neck 70 and the cap when the two are assembled together. Such plugs are, however, well known in the art and shall not be discussed further here. One of the advantages of the closure and neck assembly shown in Figure 6 is that once separated from the cap 60, the TE skirt 34 may drop down into the annular channel formed between the annular wall 74 and the neck stretch portion 72 and so be lost to view. The apparent absence of the TE skirt may serve as evidence of tampering or opening of the container. While the above embodiments have included a tamper evident member on which is provided one of the recessed and projecting portions 44, 46, other embodiments do not include a TE member. In these embodiments, the disengaging formation is provided on the container or container neck 70 itself, for example, as an integrally moulded recessed or projecting portion 44, 46 disposed on the neck stretch portion 72. Alternatively, the recessed or projecting portion may be provided on an annular wall 90 disposed externally of the container neck 70, as shown in Figure 7. The container 80 shown in Figure 7 is intended as a food storage container and is adapted for use in microwave ovens since the lid 82 is held in snap engagement with the container neck 70 and may therefore "pop" off should the pressure inside the container become too great during heating. In a further embodiment not incorporating a TE member, the complementary projecting and recessed portions 44, 46 are located on the spout member 10 and the cap member 32 respectively. One or more projecting portion 46 is provided on the spout member 10 either as a radially outwardly extending formation on the downwardly depending external wall 16 or as an upwardly extending formation on the radially outwardly extending shoulder 20. A corresponding number of recessed portions 44 is provided around the lower edge of the cap member 32, to receive the projecting portions 46. The closure 30, comprising only the cap member 32, may be placed on the spout member 10 by urging the closure axialIy downwards onto the spout member, causing the snap band 42 to move over and into engagement with the snap bead 18. However, in this embodiment, the disengagement mechanism is unidirectional, so that the closure 30 may only be rotated in one of a clockwise or anti¬ clockwise direction to effect disengagement of the snap bead and snap band. Rotation of the closure 30 relative to the spout member 10 is constrained to that one, disengaging direction by providing the profile of the recessed and projecting portions 44, 46 with a respective lifting surface and a respective rotation- obstructing surface. For example, the lifting surfaces may generally have an arcuate, quarter-circular, quarter-elliptical, straight or otherwise rising profile, so that rotation of the closure 30 relative to the spout member 10 in the disengaging direction causes the surfaces to interengage and urge the closure axially away from the spout member, thereby overcoming the snap engagement provided by the snap band 42 and the snap bead 44. The rotation-obstructing surfaces may be straight, curved, serrated or otherwise formed, but in any case have a generally greater gradient than the lifting surfaces. Preferably, the rotation-obstructing surfaces lie substantially parallel to the axis of relative rotation between the closure and spout member, i.e. substantially perpendicular to the direction of relative rotation. It will be appreciated that the rotation-obstructing surfaces may alternatively be inclined at up to 45° to this axis, while still providing the desired rotation-obstructing mechanism, albeit less effectively as the angle increases. Taking the recessed portion 44 or the projecting portion 46 as a whole, the profile is generally wedge-shaped or saw-tooth-shaped. Rotation of the closure 30 relative to the spout member 10 in the non-disengaging direction immediately causes the rotation-obstructing surfaces to interengage, whereupon further relative rotation is prevented. Further rotation of the closure 30 then causes both the closure and the spout member 10 to rotate together. As such, once the closure 30 and spout member 10 have been snapped into engagement, as previously described, the assembled closure and spout member may be driven down onto the threaded neck of a container by rotating the closure in the non-disengaging direction. Because of the rotation-obstructing surfaces, rotation of the closure causes corresponding rotation of the spout member in the same direction, while maintaining the snap engagement of the two parts. In this way, the rotation of the closure 30 is transmitted to the spout member, which may then be placed onto the container neck and screwed onto and into engagement with the neck. Provided the spout member 10 is sufficiently screwed onto the container neck, rotation of the closure 30 in the disengaging direction will not generally result in the spout member being unscrewed from the neck. Instead, the closure will rotate relative to the spout member and overcome the snap engagement between the snap bead 18 and snap band 42 under the action of the respective lifting surfaces of the recessed and projecting portions 44, 46. In other words, the lifting surfaces are so inclined to the axis of rotation as to permit relatively unimpeded rotation of the spout member and closure, with the effect that the torque required to unscrew the spout member from the container neck is greater than the torque required to rotate the closure relative to the spout member to overcome the snap engagement therebetween. While the above embodiment does not incorporate a TE member, tamper evidencing may nevertheless be employed. The various embodiments shown in figures 2 to 6 may be modified by changing the profile of the recessed and projecting portions 44, 46 on the cap member 32 and the TE skirt 34, so that they are provided with a respective lifting surface and a respective rotation-obstructing surface. Assembly of the closure 30 onto the spout member 10 is the same as that described with reference to figures 3a and 3b. Removal of the cap member 32 from the spout member 10 for the first time - breaking the frangible bridges 36 between the TE skirt 34 and leaving the skirt behind on the spout member - and thereafter is the same as that described with reference to figures 4a and 4b, except that the cap member may be rotated in the disengaging direction only to achieve this. If the spout member 10 is not already screwed onto a container neck before the closure 30 is to be snapped onto the spout member, the two parts may be assembled first and then placed over the neck and screwed onto it by rotating the closure in the non- disengaging direction. Because in this embodiment the recessed and projecting portions 44, 46 are arranged between the cap member 32 and the TE skirt 34, rotation of the cap member in the non-disengaging direction is transmitted to the TE skirt upon contact of the rotation-obstructing surfaces, tending to cause the closure 30 to rotate as a whole. While there is no direct mechanism between the cap member 32 and the spout member 10 preventing relative rotation therebetween, significant relative rotation between the spout member and the TE skirt 34 is prevented by the anti-rotation lugs 22, 50. As such, rotation of the cap member 32 in the non-disengaging direction not only causes the TE skirt 34 to rotate together with it, but also the spout member 10. This is the case both when the frangible bridges 36 have been broken and when they are still intact. In the latter case, the limited relative rotation between the cap member 32 and the TE Skirt 34 in the non-disengaging direction, which takes place until the rotation-obstructing surfaces interengage, is not sufficient to break the frangible bridges 36. Accordingly, during manufacture of an assembled container and closure, the closure and spout member together may be screwed onto a container neck by gripping the cap member 32 and rotating it in the non- disengaging direction so as to cause the spout member to rotate and the complementary threads on the outside of the neck and" the inside of the spout member wall 24 -to interengage, while maintaining intact the frangible bridges 36, thereby preserving the tamper evidencing mechanism. Although the above embodiments are preferred, the present invention extends also to the following embodiments. In the above embodiments, two discrete and complementary recessed and projecting portions 44, 46 have been described. In the embodiment shown schematically in Figure 8, the closure 30 comprises one recessed portion 44a and one projecting portion 46b while the container neck 70 comprises one projecting portion 46a and one recessed portion 44b. In previous embodiments, the angle subtended by one of the recessed or projecting portions 44, 46 (that is, its circumferential extent) was relatively small. By- contrast, the embodiment shown in Figure 8 is an extreme case in which the angle subtended by one of the recessed or projecting portions 44a,b, 46a,b is 180°. As such, there is no generally horizontal region on either the lower rim of the closure 30 or on a shoulder 78 of the neck 70 on which the lower rim rests. However, the snap band 42 and the snap bead 18 are still generally horizontal and parallel with one another, occupying respective radial planes. Upon rotation of the closure 30 with respect to the container neck 70, the projecting portion 46b of the closure is brought into confrontation with the recessed portion 44b of the container neck, forcing the closure upwards and away from the container neck. The axialIy upward motion of the closure 30 causes the snap band 42 to disengage from the snap bead 18 as before. An alternative embodiment to that described above is shown schematically in Figure 9. Here, the lower rim of the closure 30 and the shoulder 78 of the container neck 70 are generally horizontal, occupying radial planes, but the snap band 42 and snap bead 18 are inclined to the horizontal. This can be considered as an extreme case in which the disengaging formations 44, 46 are provided on the snap band 42 and the snap bead 18 themselves, and the disengaging formations again subtend 180° of arc. In this case, relative rotation of the closure 30 and the container neck 70, causes the snap band 42 to disengage from the snap bead 18 and so to overcome the snap engagement. A less extreme case is illustrated in Figure 10 in which two projecting portions 46a,b are provided on a snap band 42 disposed on an internal surface of a closure (not shown) and two recessed portions 44a,b are provided on a snap bead 18 disposed on an external surface of a container neck (again, not shown) . Here, again, relative rotation of the closure 30 and the container neck 70 cause the recessed and projecting portions 44a, b, 46a, b to be brought into disengaging intersection so that the snap engagement is overcome.




 
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