Patent Publication Number: US-8523009-B2

Title: Container closure with deformable region in skirt to allow pivoting

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application under 35 USC 371 of International Application No. PCT/AU2006/000436, filed Mar. 31, 2006, which claims priority from an Australian patent application No. 2005901579, filed Mar. 31, 2005, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     (i). Field of the Invention 
     An improved closure for a container is disclosed wherein at least the closure (eg. in the form of a lid) is moulded from plastic. More particularly, the closure is adapted for reuse, but to also indicate tampering once initially removed. 
     (ii). Description of the Related Art 
     Plastic and metal containers such as pails are used for holding chemicals including paints, solvents, oils, powders etc. It is desirable that the closure does not become detached from the container as a result of inadvertent dropping of the container and/or from shifting loads during handling, transport etc. At the same time, it is desirable that the closure be readily removable when access to container contents is required. 
     GB 2091706 discloses a container lid provided with a lid flange that merges into a releasing flange. The releasing flange can assume a position in which an inwardly extending rib of the flange can engage a sealing edge on a container flange or a container external bead. The releasing flange is fabricated to have a thin cross-section so that it can act as a bistable snap catch to be pivoted to an extreme position to release from the container flange or external bead, and be retained thereat by means of its inherent annular tension. 
     WO 2004/106185 discloses a container-closure arrangement in which the container comprises external and internal beads formed at the container rim, and a closure having first and second ledges for interlocking engagement with the respective external and internal beads. However, to enable closure removal from the container, a tear strip comprising the first ledge requires detachment from the closure so that the first ledge can be moved from its interlocking engagement with the external bead. 
     A reference herein to a prior art document is not an admission that the document forms a part of the common general knowledge of a skilled person in Australia or elsewhere. 
     SUMMARY OF THE INVENTION 
     A closure is provided for a container that comprises a base and peripheral wall, with a rim forming an upper margin of the wall and surrounding an opening of the container, and an external protrusion formed integrally with and surrounding the rim; 
     a portion of the closure being adapted to overlie the opening of the container, with a skirt formed integrally with the closure portion and arranged to surround the rim when the closure is mounted to the container, the skirt comprising a first portion positionable adjacent to and to surround an external upper end of the rim, and a second portion that is connected to the first portion at a connection and that extends downwardly therefrom to surround the rim below its upper end, the second portion comprising an integrally formed first ledge located therewithin, the first ledge being positionable to locate in interlocking engagement with the external protrusion; 
     wherein at least one region of deformability is defined in the second portion at a location away from the connection such that, with the closure mounted on the container, the at least one region can deform to facilitate pivoting of the second portion with respect to the first portion to disengage the first ledge from the external bead. 
     By providing at least one region of deformability in the second portion it has been observed that its pivoting is more easily enabled. However, region deformation during pivoting can also indicate tampering with the closure, and hence potential tampering with container contents. 
     In one form the second portion is adapted to pivot to a position whereby closure removal from the container is enabled. This position may comprise a stable position whereby the second portion can be adapted to maintain itself in that position once pivoted thereto. In this regard, the second portion typically has a substantial cross-sectional thickness such that, without the at least one region of deformability, pivoting of the second portion to the stable position is either rendered difficult or prevented. The substantial cross-sectional thickness can be contributed to in part by the first ledge. 
     The at least one region of deformability is also compatible for use with a closure and container that employ primary and secondary locking of the closure with the container. In this regard, the interlocking engagement of the first ledge with the external protrusion can provide a “primary locking” of the closure to the container. To provide “secondary locking” an internally extending protrusion can be formed integrally with and around the container rim to project inwardly from the rim. Then, a second ledge can be formed integrally with the closure portion that can interlockingly engage with the internal protrusion when the closure is mounted on the container. Disengagement of the first ledge from the external protrusion thus releases the primary locking, whereby closure removal from the container then requires only the secondary locking to be disengaged. Thereafter, upon closure re-mounting to the container, the secondary locking can be re-engaged (via the second ledge and internal protrusion) to securely remount the closure to the container, whether or not the primary locking is re-engaged. The provision of primary and secondary locking also facilitates a more secure mounting of the closure to the container (eg. during transport, storage etc) such that, when the closure is initially mounted on the container, it is secured thereto on both sides of the rim. 
     The external and internal protrusions may be provided in the form of beads that are integrally formed with the container rim. 
     The at least one region of deformability can be provided as a web (eg. of reduced thickness compared to the rest of the second portion) that extends transversely through the second portion, or may be defined by a line of weakness or severance, or simply by a thinning of material in a given region. In addition, during pivoting of the second portion with respect to the first portion, the region of deformability may stretch or break. Typically at least two regions of deformability are provided in the second portion, for example, located on opposite sides of the closure. 
     In one form of the container, a container flange can be formed integrally with and to extend out from the container wall below the rim. The container flange typically functions to strengthen the container adjacent to the rim. Typically the length of the second portion is such that its distal end is positioned adjacent to the container flange when the closure is mounted to the container, typically in a close facing relationship (which can include abutment of the second portion distal end at the container flange). Locating the distal end of the second portion adjacent to the container flange can further assist with tamper proofing the arrangement. For example, an attempt to remove the closure from the container may require the insertion of an implement (eg. a blade) between the second portion distal end and the container flange, which may then be detected (eg. as a deformation of either of both of the second portion or flange). 
     However, in one embodiment the container flange is typically provided with one or more recesses adapted for receiving finger(s) of a user therein to facilitate finger insertion under and lifting of the second portion, thus facilitating initiation of pivoting of the second portion with respect to the first portion. In another embodiment the second portion can be provided with one or more recesses adapted for receiving finger(s) of a user therein to facilitate finger insertion under and lifting, and thus initiation of second portion pivoting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Notwithstanding other embodiments which may incorporate some or all of the closure features as outlined in the Summary, a number of specific closure and container embodiments will now be described, by way of example only, with reference to the accompanying drawings in which: 
         FIG. 1  shows a side view of an assembled container-closure arrangement; 
         FIG. 2  shows a perspective detail of the closure of  FIG. 1  and illustrating a region of deformability; 
         FIG. 3  shows a side sectional view through part of the assembled container-closure arrangement of  FIG. 1  in a closure “un-flipped” configuration; 
         FIG. 4  shows a view similar to  FIG. 3  but with the closure in a “flipped” configuration; 
         FIG. 5  shows a view similar to  FIG. 3  but taken at a location where a flange of the container has a preformed finger recess defined therein; 
         FIG. 6  shows a perspective detail of the container-closure arrangement of  FIG. 1  and illustrating part of the closure in a “flipped” configuration; and 
         FIG. 7  shows a sectioned perspective detail of the container-closure arrangement of  FIG. 1  and illustrating part of the closure in a “flipped” configuration and an underlying preformed finger recess in the container flange. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , an assembled container-closure arrangement is depicted comprising a container in the form of a pail  10 , and a closure in the form of a lid  11 . Whilst the arrangement is typically employed with a circular pail and lid as shown, the arrangement may be employed with square or rectangular pails and lids etc. 
     The pail and lid may each be moulded from polypropylene or high density polyethylene. The pail may be moulded in any desired size and may have a volumetric capacity in the order of eg. 0.5 to 20 liters. The pail may also be formed from a metal material. In addition, the lid-pail arrangements are suited to both tapered ( FIG. 1 ) and straight-sided containers. 
     The pail  10  has a base  13  which is sized so that it can be located at a recess portion of the lid. In this regard, the recess portion includes a generally flat central region  14  ( FIG. 2 ) whereby the base of an overlying pail can be positioned at region  14 , so that a number of the pail-lid arrangements may be stacked one upon another. The pail has a peripheral wall  15 , with a rim  16  forming an upper margin of the wall  15  and surrounding an opening of the pail ( FIG. 3 ). 
     Referring now to  FIG. 2 , the lid  11  comprises a skirt  20  which surrounds the rim  16  when the lid is first mounted to the pail. Skirt  20  comprises first  21  and second  22  skirt portions, with the second skirt portion optionally also functioning as a removable tear strip or band. In this regard the second skirt portion  22  depends from and is connected (optionally frangibly) to the first skirt portion  21  by way of an integrally moulded thin connecting web  23 . The web  23  functions as a living hinge between the first and second skirt portions to enable pivoting of the second skirt portion with respect to the first skirt portion (as described below). 
     The skirt  20  is generally formed as a continuous wall depending from and extending peripherally around the lid, save for the provision therein of one or more regions of deformability. Each such region is depicted in the form of a transversely extending skirt recess  24  defined in the second skirt portion  22 . Typically at least two such recesses are provided in the skirt portion  22 , usually on opposing sides of the lid. Whilst each region of deformability is typically embodied as a recess, each region may take other forms, such as a line of material weakness, a line of perforations, a score line, a more general region of reduced thickness etc. 
     In the embodiment depicted, each transverse recess  24  is defined by a thin web  25  of skirt material that extends across sides  26 ,  27  of the skirt portion  22  opposed across the recess. The webs  25  are adapted to not permanently deform during first mounting of the lid on the pail. However, deformation or severing (breaking) of webs  25  enables the second skirt portion to be pivoted (or “flipped”) upwardly (as shown in  FIGS. 4 ,  6  and  7 ). The now upwardly extending skirt portion  22  can be grasped and pulled to complete lid removal. 
     In an optional variation, the webs  23  and  25  can be fabricated to enable the second skirt portion  22  to function as a removable tear strip or band. In this regard, the web  23  can be frangible or be defined by a line of severance (eg. to be cut with a knife). The opposing sides  26 ,  27  may each constitute a strip free end, thus providing a manually accessible point of initiation for tearing and removal of skirt portion  22 . The sides  26 ,  27  could also include slightly protruding mouldings or formations to facilitate easier manual grasping. However, should skirt portion  22  be provided as a removable as a tear strip subsequent lid removal may then require the use of a tool. 
       FIG. 3  shows another optional arrangement where the lid and pail are each adapted for the stacking of one laden container on another. In this regard, the pail rim  16  is offset with respect to the pail wall  15 , to define a shoulder  28 . The shoulder  28  in turn defines an internal step  29  in the wall  15 . A lid stacking skirt  30  can then be provided to extend from an underside of lid  11 , the skirt combining with a land  31  of the lid to define an inverted U-shaped channel into which the rim  16  can be inserted when mounting the lid to the pail. Whilst the stacking skirt  30  provides additional rigidity to lid-pail mounting, it also enables one or more laden (eg. like) containers to be stacked on the lid  11 . In this regard, the stacking skirt receives the mass of laden container(s) and transfers this mass to the step in the container wall, with the wall then transferring this mass to its base. This can prevent inward collapse of the lid under load. 
     A land recess  31 A ( FIG. 3 ) can provided in land  31  and this recess can receive therein a lower end of the lid stacking skirt  30  of an overlying lid (eg. when one lid is stacked onto another such as after production and for transportation). 
     In  FIG. 3 , it will also be seen that the pail rim  16  includes an external protrusion in the form of projecting bead  32  that is formed integrally with and surrounds the rim, the bead  32  being spaced from an upper free end  33  of the rim. The bead  32  has an undersurface  34  that extends from an outer surface  35  of the rim  16 . An internal protrusion in the form of projecting bead  36  is formed integrally with and extends internally of and around the rim  16 , the bead  36  being defined as part of the rim upper free end  33 . The bead  36  has an undersurface  37  that extends from an inner surface  38  of the rim  16 . 
     The bead  32  provides for primary locking of lid  11  to pail  10 . Also, where the second skirt portion  22  has been pivoted (or “flipped”) up but not detached, as shown in  FIG. 4 , it can again be pivoted back down to re-establish the primary locking function. 
     The bead  36  provides for secondary locking of lid  11  to pail  10 . For example, after the skirt portion  22  has been disengaged from bead  32  (to remove or disengage primary locking) such secondary locking enables the lid to be re-secured to the pail. 
     Further, the spacing of the beads as shown, together with the incorporation of bead  36  into rim upper free end  33 , make it easier for the lid  11  to be removed from container  10 . In this regard, by locating the bead  32  such that is spaced from the rim free end, and by defining the bead  36  as part of the rim free end, once the first ledge is disengaged from the external bead, it is easier to disengage the ledge  42  from the bead  36  (eg. its location and orientation enables pealing away of the lid from the pail). 
     As part of the primary locking of lid  11  to pail  10 , the second skirt portion  22  comprises an inwardly projecting ledge  40  for interlocking engagement with the bead  30  when the lid is first mounted onto the pail as shown. As stated above, pivoting (or “flipping”) up of second skirt portion  22  around the hinge defined by web  23  disengages ledge  40  from the bead  32  ( FIG. 4 ). 
     As part of the secondary locking of lid  11  to pail  10 , the lid  11  comprises a ledge  42  projecting inwardly and downwardly from the land  31  of the lid. The ledge  42  interlockingly engages with the bead  36  when the lid is mounted to the pail as shown. As stated above, the ledge  42  and bead  36  are typically configured such that, once second skirt portion bead  32  has been disengaged from ledge  40 , the lid may now be “peeled” off the pail by a manual peeling force, that causes bead  36  to disengage with ledge  42 . 
     The dual interlocking engagement between beads  32 ,  36  and ledges  40 ,  42  enables the lid to be securely fastened to the pail in that, once assembled, the lid is secured around its periphery by locking on to the beads on both sides of the rim  16 , with the rim  16  accordingly being secured within the U-shaped channel. This assists with secure transport and storage of the pail contents. 
     As also shown in  FIG. 3 , the second skirt portion  22  has an increased thickness relative to the remainder of skirt  20 . The thickness is contributed to in part by the ledge  40 . This thickness builds a tensile resistance into the portion  22  that causes the ledge  40  to be urged under (or behind) the bead  36  (ie. in a kind of snap-lock) once the ledge has moved past the bead during mounting of the lid to the pail. In this regard, the thickness and/or skirt material is selected to allow deformation of the second skirt portion during movement past the bead  36 , but to impart sufficient resilience to cause the skirt portion to spring back to its original dimension once in the location shown in  FIG. 3 . 
     The increased thickness of skirt portion  22  also introduces bi-stability to the portion. That is, it locks in the position of  FIG. 3  but, when pivoted (or “flipped”) upwardly ( FIG. 4 ), the portion  22  is also held in that position by the tensile resistance. In other words, the skirt portion  22  is stable in two positions (ie. when pivoted down and when pivoted up). 
     Further, because of the increased thickness the region(s) of deformability also function to enable pivoting of the skirt portion  22 . In other words, without the region(s) of deformability pivoting would either be rendered difficult or prevented. 
       FIG. 3  also clearly shows an annular pail flange  50  formed integrally with the rim  16 , the flange projecting to surround the pail peripheral wall  15  and serving, inter alia, to strengthen the pail wall. The flange is located below the level of the bead  32  to define a circumferential groove  51  for the receipt therein of skirt ledge  40 . The flange comprises a ledge portion  52  formed integrally with, surrounding and extending out from the rim  16 , and a wall portion  54  subtending from the ledge portion  52 . The ledge portion  52  is slightly downwardly inclined with respect to the rim  16  (but may extend generally orthogonal thereto). 
     The flange  50  can also contribute to the tamper-proof mounting of the lid to the pail. In this regard, the second skirt portion  22  is sloped at its free end  55  to match the inclination of ledge portion  52 . Further, free end  55  extends down to the ledge portion  52  in a close facing relationship when the lid is mounted to the pail. This close facing relationship (which may eg. be abutment) provides a tamper-proof region between the lid and pail and can help to prevent the insertion of a knife or other sharp or bladed instrument between the lid and pail. However, should such an attempt be made, the close facing relationship ensures that deformation or other damage will result, thereby providing a visual or tactile indication of tampering. 
     Whilst the flange  50  strengthens the pail it also provides resistance to lateral bumps and blows during transportation. In this regard, and as shown in  FIG. 3 , the flange projects laterally further than the lid, and thus preferentially receives and absorbs bumps, blows etc. This further contributes to a secure lid mounting in use. 
     The flange may also comprise one or more recesses  60  extending part-way around the flange to accommodate and enable a user&#39;s fingers to be inserted therein (see  FIGS. 1 and 5  to  7 ). Each recess facilitates lifting and pivoting (“flipping”) of the second skirt portion  22 . This lifting may alternatively be facilitated by an appropriately shaped tool. Recesses may additionally or alternatively be provided in the second skirt portion  22 . 
     Mounting of the lid to the pail may be easily facilitated by hammering the lid onto the pail around land  31 , or by positioning a plate or ring-shaped tool onto land  31  of the lid  11  (the plate or tool may optionally have a diameter generally corresponding to land  31 ). A user (or machine) may then press on the plate or tool to force the lid onto the pail. In any case, during mounting the ledges  40 ,  42  slide past beads  32 ,  36 , until the position of  FIGS. 1 and 3  is reached. 
     In use, after the container has been filled and the lid has been mounted to the pail, when a user requires access to the pail contents, the second skirt portion  22  is either lifted and pivoted to the positions in  FIGS. 4 ,  6  and  7  by a user inserting fingers into recess  60 , or is removed (eg. as a tear strip), in either case detaching ledge  40  from bead  32 . 
     The lifting and pivoting of second skirt portion  22  can occur in one or two stages. For example, half of the skirt portion  22  can be lifted when the lid comprises two (eg. opposing) transverse recesses  24 . In this case the web  25  of each recess can sever to enable half-skirt pivoting. This is shown in  FIGS. 6 and 7 . 
     Alternatively or additionally, both skirt portion  22  halves can be lifted sequentially or simultaneously, in which case the web  25  of each recess can sever or deform to enable full pivoting of skirt portion  22 . Where more than two transverse recesses  24  are employed, various sequences of part-skirt pivoting may ensue. 
     In any case, when half the skirt portion  22  is pivoted as shown in  FIG. 6  the lid is at least partially released from its primary locking position. Depending on the length of the skirt portion that is lifted and pivoted, this may now be sufficient to then enable lid removal. Typically, however, all of the part-skirt portions  22  are pivoted upwardly to best facilitate lid removal. 
     Then, to complete lid removal, a user may by hand or through the use of an appropriate tool now lift the lid away from the pail to detach ledge  42  from bead  36  (releasing the secondary locking). For example, the upwardly extending (pivoted) skirt portion  22  can be grasped and pulled to effect complete lid removal. In effect, the lid  11  is pealed back from pail  10  to allow access to the pail contents. After such access the lid can be re-mounted by pushing it back on to the pail until ledge  42  interlockingly engages with bead  36 , thus partly re-sealing the pail contents. The second skirt portion may optionally then be pivoted back into the primary locking position (eg. when the pail contents are to be stored, transported or later used). 
     One desirable application for the pivotable second skirt portion  22  configurations described is where a further substance needs to be added and mixed with the pail contents (eg. tinting for paint). After pivoting skirt portion  22  away and pealing back the lid  11  from pail  10 , to allow access to pail contents, the further substance can be added to the pail, the lid can be re-mounted by pushing it back on to the pail until ledge  42  interlockingly engages with bead  36 , thus partly re-sealing the pail contents and, as necessary, the second skirt portion  22  can be pivoted back into the primary locking position. Now the pail and lid can be shaken etc to mix in the further substance. 
     Another benefit in employing one or more regions of deformability (such as transverse recesses  24 ) is that a user can ascertain if an initially mounted lid has been removed or otherwise tampered with, as the region(s) will deform (stretch or break) and thus reveal tampering. 
     In the embodiments described the lid is formed from deformable and/or deflectable materials to facilitate its mounting onto and removal from the pail. On the other hand, and as required, the pail may be formed from deformable or non-deformable materials such as plastic or metal etc. 
     Whilst a number of embodiments have been described, it will be appreciated that the closure arrangements described can be embodied in many other forms. 
     In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the closure.