Abstract:
Disclosed is a product package which includes a sleeve and at least on rigid end cap. The sleeve has longitudinally opposed first and second ends, the first end of the sleeve defining an opening and having at least two locking tabs extending therefrom. The first end of the sleeve also includes a tear strip positioned adjacent to the opening which has been formed using known techniques, such as, microperforation. Each locking tab includes a locking edge and is folded inwards into the opening. A rigid end cap is dimensioned to fit closely within the sleeve opening, the end cap including a rim that, when the end cap is inserted into the opening, engages the first end of the sleeve and prevents the end cap f I-rom being inserted further into the opening. The end cap also includes at least one channel for receiving the pair of locking tabs, the at least one channel having a ledge that engages the locking edge of each locking tab to prevent the end cap from being removed from the sleeve opening. The tear strip formed in the sleeve is adapted and configured such that pulling the tear strip allows the rigid end cap to be removed from the sleeve opening. The tear strip can also include a finger tab that is accessible to a user.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of priority to U.S. Provisional Patent Application No. 60/760,721 filed Jan. 20, 2006 and is continuation in part of U.S. patent application Ser. No. 10/521,349 filed Jan. 13, 2005, which claims priority to International Application No. PCT/US2003/022528 filed Jul. 17, 2003, which claims priority to U.S. Provisional Patent Application No. 60/396,504 filed Jul. 17, 2002, each of which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to the field of product packaging, and in particular to product packages that have a locking end cap that is released by partial destruction of the package using a tear strip. 
         [0004]    2. Background of the Related Art 
         [0005]    Product packaging serves a number of different functions, including: protecting the packaged product from accidental damage, attractively displaying the packaged product and preventing theft or tampering. In addition, it is desirable for a package to be as inexpensive to manufacture as possible. Assignee&#39;s co-pending application, U.S. patent application Ser. No. 10/164,477 (filed on Jun. 6, 2002), the entirety of which is incorporated herein by reference, discloses one such improved design. 
         [0006]    However, there is an ongoing need in the packaging industry for new package designs which can be more readily manufactured and require less material than conventional packaging and also provide tamper resistant features. 
       SUMMARY OF THE INVENTION 
       [0007]    Disclosed is a product package which includes a sleeve and at least one rigid end cap. The sleeve has longitudinally opposed first and second ends, the first end of the sleeve defining an opening and having at least two locking tabs extending therefrom. The first end of the sleeve also includes a tear strip positioned adjacent to the opening which has been formed using known techniques, such as, microperforation. Each locking tab includes a locking edge and is folded inwards into the opening. A rigid end cap is dimensioned to fit closely within the sleeve opening, the end cap including a rim that, when the end cap is inserted into the opening, engages the first end of the sleeve and prevents the end cap from being inserted further into the opening. The end cap also includes at least one channel for receiving the pair of locking tabs, the at least one channel having a ledge that engages the locking edge of each locking tab to prevent the end cap from being removed from the sleeve opening. The tear strip formed in the sleeve is adapted and configured such that pulling the tear strip allows the rigid end cap to be removed from the sleeve opening. The tear strip can also include a finger tab that is accessible to a user. 
         [0008]    In accordance with another aspect of the invention, the end cap can include a cavity shaped to receive an end of a product to be packaged. It is also contemplated that the end cap can include a plurality of cavities shaped to receive a product to be packaged. 
         [0009]    In another aspect in further accordance with the invention, the locking tabs of the first end of the sleeve can be dimensioned and configured to releasably engage an exterior surface of the peripheral wall of the first end cap. It is also contemplated that the locking tabs of the first end of the sleeve can be adapted and configured for folding into the sleeve to releasably engage the peripheral wall of the first end cap. 
         [0010]    In accordance with a further aspect of the invention, the sleeve and locking tabs can have a strength and resilience that combines with the dimensioning and angling of the ledges to produce a firm locking action when the locking tabs are engaged by the ledges. Each of the locking tabs and the channels can be shaped such that the end cap is twistable to a position in which the locking tabs are clear of the ledges, thereby releasing the end cap from the sleeve. Each of the locking tabs can be trapezoidal and have an acute vertex that rides up a side edge of the channel when the end cap is twisted relative to the sleeve, such that the end cap is released from the sleeve. It is also contemplated that the channel can have at least one ramped side edge, such that when the end cap is twisted relative to the sleeve, the locking tab rides up the ramped side edge, such that the end cap is released from the sleeve. 
         [0011]    In accordance with still another aspect of the invention, the channels and locking tabs can be shaped such that the end cap is prevented from twisting and releasing the end cap from the sleeve. The locking tabs and channels can be rectangular to prevent the locking tabs from riding up a side edge of the channel when the end cap is urged to twist relative to the sleeve, such that the end cap is prevented from being twisted and released from the sleeve. 
         [0012]    In accordance with another aspect of the invention, the sleeve can include a second end defining a second opening, and the package can further include a second locking tab and a second end cap. The second locking tab can extend from the second end and can be folded inward into the second opening, the second locking tab having a locking edge. The second end cap can have a substantially continuous outer surface dimensioned to fit closely within the second opening. The second end cap can further include a rim overhanging the outer surface such that, when the second end cap is inserted into the second opening, the rim engages the second sleeve end and prevents the second end cap from being inserted further into the second opening. The second end cap can further include a channel for receiving the second locking tab, the channel having a ledge that engages the locking edge of the second locking tab to prevent the second end cap from being removed from the second sleeve opening. It is also contemplated that the first and second end caps can each include a cavity shaped to receive an opposite end of a product to be packaged. 
         [0013]    In accordance with still another aspect of the invention, the sleeve can be defined by opposed first and second curved panels. The first and second curved panels can be connected to one another along lateral edges of the sleeve. The first and second curved panels can be integrally joined to one another along a first lateral edge of the sleeve. The first and second curved panels can also be affixed to one another along a second lateral edge of the sleeve. 
         [0014]    The invention also includes a package having a sleeve, a first rigid end cap, and a second rigid end cap. The sleeve has longitudinally opposed first and second ends, the first and second ends of the sleeve each defining an opening and having at least two locking tabs extending therefrom. The first end of the sleeve further includes a tear strip positioned adjacent to the opening. Each locking tab includes a locking edge and can be folded inwards into the opening. The first rigid end cap is dimensioned to fit closely within the sleeve opening. The first end cap includes a rim that, when the first end cap is inserted into the first sleeve opening, engages the first end of the sleeve and prevents the first end cap from being inserted further into the first sleeve opening. The first end cap further includes at least one channel for receiving the pair of locking tabs in the first end of the sleeve, the at least one channel having a ledge that engages the locking edge of each locking tab to prevent the end first cap from being removed from the first sleeve opening. The second rigid end cap is dimensioned to fit closely within the second sleeve opening and can including a rim that, when the second end cap is inserted into the second sleeve opening, engages the second end of the sleeve and prevents the second end cap from being inserted further into the second sleeve opening. The second end cap also includes at least one channel for receiving the pair of locking tabs in the second end of the sleeve, the at least one channel having a ledge that engages the locking edge of each locking tab of the second end cap to prevent the second end cap from being removed from the second sleeve opening. The tear strip is adapted and configured such that pulling the tear strip allows the rigid end cap to be removed from the sleeve opening. It is also contemplated that each of the locking tabs of the first end of the sleeve and the channels of the first end cap can be shaped such that the first end cap is twistable to a position in which the locking tabs are clear of the ledges, thereby releasing the first end cap from the sleeve. 
         [0015]    The invention also includes a method for fabricating a package. The method includes the steps of cutting and scoring a sleeve blank to create first and second panels, a glue flap extending from the first panel, locking tabs extending from each of the panels, and a tear strip proximate to one of the locking tabs. The method further includes folding the second panel over the first panel, folding the glue flap and affixing it to the second panel so the first and second panels form a sleeve, folding the locking tabs inward into the sleeve, and inserting a rigid end cap into a first end of the sleeve, the end cap including at least one channel having a ledge that engages a locking edge of each locking tab extending from the first end of the sleeve. The method also includes steps of loading a product into the sleeve and inserting a second rigid end cap into a second end of the sleeve, the second end cap including at least one channel having a ledge that engages a locking edge of each locking tab extending from a second end of the sleeve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The presently disclosed embodiments will be further explained with reference to the attached drawings, wherein like structures are referred to by like numerals throughout the several views. The drawings are not necessarily to scale, the emphasis having instead been generally placed upon illustrating the principles of the presently disclosed embodiments. 
           [0017]      FIG. 1  shows a perspective view of a product package constructed in accordance with an embodiment of the present invention; 
           [0018]      FIGS. 2 and 3  show front and rear views of the package shown in  FIG. 1 ; 
           [0019]      FIGS. 4 and 5  show left and right side views of the package shown in  FIG. 1 ; 
           [0020]      FIGS. 6 and 7  show top and bottom views of the package shown in  FIG. 1 ; 
           [0021]      FIGS. 5 and 9  show, respectively, elevational views of an upper and lower end cap according to an embodiment of the present invention; 
           [0022]      FIG. 10  shows a plan view of a blank for fabricating a sleeve according to an aspect of the invention; 
           [0023]      FIG. 11  shows a plan view of the blank shown in  FIG. 10 , partially fabricated into a sleeve; 
           [0024]      FIG. 12A  shows a plan view of the blank shown in  FIG. 10 , fully assembled into a sleeve; 
           [0025]      FIG. 12B  shows a side view of the blank shown in  FIG. 12A ; 
           [0026]      FIGS. 13A-D  show a series of diagrams illustrating the operation of a locking mechanism according to an aspect of the invention; 
           [0027]      FIG. 14  shows a cutaway view of a sleeve and end cap illustrating the operation of a locking mechanism according to an aspect of the invention; 
           [0028]      FIG. 15  shows a cutaway view of a sleeve and upper and lower end caps illustrating the operation of a locking mechanism according to an aspect of the invention; 
           [0029]      FIGS. 16A-D  and  17 A-D are a series of diagrams illustrating the operation of a release mechanism according to an aspect of the invention; 
           [0030]      FIGS. 18A and 18B  are diagrams illustrating the operation of the release mechanism illustrated in  FIGS. 16A-D  and  17 A-D; 
           [0031]      FIGS. 19A-D  and  20 A-D are a series of diagrams illustrating the operation of a release mechanism according to a further aspect of the invention; 
           [0032]      FIG. 21  shows a perspective view of a package according to another aspect of the invention; 
           [0033]      FIGS. 22 and 23  show front and rear views of the package shown in  FIG. 21 ; 
           [0034]      FIGS. 24 and 25  show left and rear side views of the package shown in 
           [0035]      FIG. 21 ; 
           [0036]      FIGS. 26 and 27  show top and bottom views of the package shown in  FIG. 21 ; 
           [0037]      FIG. 28  shows a perspective view of a package according to another aspect of the invention; 
           [0038]      FIGS. 29 and 30  show front and rear views of the package shown in  FIG. 28 ; 
           [0039]      FIGS. 31 and 32  show left and right side views of the package shown in  FIG. 28 ; and 
           [0040]      FIG. 33  shows a top view of the package shown in  FIG. 28 . 
       
    
    
       [0041]    While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the presently disclosed embodiments. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0042]    The presently disclosed embodiments are directed towards product packaging that includes, inter alia, a sleeve that has at least one end that is closed by inserting an end cap. In addition, the sleeve comprises a tear strip which allows a user to disengage the end cap from the sleeve. The tear strip is in communication with a tab wherein the tab is accessible to a user. Once the tear strip has been removed, a user may remove the end cap. 
         [0043]    Depending upon the use for the package, the sleeve may be closed with two non-releasable locking caps, two releasable locking caps, or one non-releasable locking cap and one releasable locking cap. In addition, the sleeve may comprise a single tear strip located at a first opening or a first tear strip at a first opening and a second tear strip at a second opening. 
         [0044]    The use of at least one tear strip may be desirable for a number of reasons. First, use of a tear strip allows for increased theft prevention. Use of the tear strip requires damage to the sleeve which is easier to detect by store personnel as opposed to the use of a twist off end cap. In addition, a customer may find a twist off end cap to be cumbersome if the product is too large As such, removal of the tear strip provides a helpful alternative to a twist off releasable cap. 
         [0045]      FIG. 1  shows a perspective view of an embodiment of the presently disclosed product package  10 . The package  10  includes a sleeve  12  having an upper opening at an upper end and a lower opening at a lower end. The sleeve comprises a tear strip  52  engaged to a tab  50 . The tear strip  52  is a perforated section of the sleeve which facilitates tearing of the sleeve along the perforated section. The tear strip  52  is located in a position such that tearing along the perforation will allow for the release of the end cap. The mechanics of the end cap  14  will be discussed in detail below. 
         [0046]    The tab  50  is accessible to a user so that the user may grab the tab  50  and exert a tearing force along the tear strip  52 . Once the user has torn the tear strip  52  along substantially a desired length of the tear strip, the end cap  14  may be easily removed by a user. Those skilled in the art will recognize that any shape tab is within the spirit and scope of the present invention. 
         [0047]    The sleeve  12  may suitably be fabricated from a sheet of see-through plastic material, such as PVC, APET, PETG, polylith, PLA or the like. The thickness of the sheet is selected based on a number of factors, including price and strength. The sheet should be thick enough to provide structural support, but thin enough to allow the sheet to be flexed and folded, as described herein. 
         [0048]    As will be discussed in detail below, the sleeve  12  comprises a pair of locking tabs  18  adjacent to the upper opening. As the end cap  14  is pushed into the upper opening of the sleeve  12 , the locking tabs  18  are secured in a channel  22  of the end cap  14 . Depending on the length, position and number of locking tabs  18  relative to the channel  22 , the end cap  14  may be a releasable locking mechanism or a non-releasable locking mechanism (will be discussed below). If a releasable locking mechanism, the end cap  14  may be released by applying a twisting motion to the end cap  14 . Presently disclosed embodiments are directed towards the use of the tear strip  52  with either a releasable end cap or an unreleasable end cap. Tearing the tear strip  52  along the perforated edge allows for the user to remove an end cap  14  (either releasable or non-releasable) because once the tear strip has been ripped the user may easily disengage the locking tabs  18  from the channel  22  of the end cap  14 . The tear strip  52  may be used in conjunction with a releasable end cap if the container  10  is too cumbersome to apply a twisting motion. 
         [0049]    As stated, the sleeve  12  includes an upper pair of locking tabs  18  that are folded inwards into the interior of the sleeve  12  for securing the upper end cap  14 , and a lower pair of locking tabs  20  that are folded inwards into the interior of the sleeve  12  for securing the lower end cap  16 . As further described below, the upper end cap  14  includes a pair of channels  22  corresponding in position to the pair of upper locking tabs  18 . The lower end cap  16  includes a single continuous channel  24  encircling the perimeter of the lower end cap  16 . 
         [0050]    As described below, different channel arrangements are used to create, respectively, a releasable locking mechanism and a non-releasable locking mechanism.  FIG. 1  shows an embodiment wherein the upper end cap  14  is secured with a releasable locking mechanism in association with a tear strip  52  and the lower end cap  16  is secured with a non-releasable locking mechanism. In this embodiment, the upper end cap  14  may be released by twisting the upper end cap  14  within the sleeve  12 . If a user finds the container too cumbersome too twist, the user may tear the tear strip  52  along the perforated edge in order to disengage the locking tabs  18  from the channel  22  and remove the end cap. In another embodiment, the upper end cap is a non-releasable end cap and the user must tear the tear strip along the perforated edge to remove the end cap. As shown in  FIG. 1 , the lower end cap  16  is not releasable, and cannot be removed without causing damage to the package  10 . In an embodiment, the lower end cap may also be associated with an additional tear strip. 
         [0051]    As further shown in  FIG. 1 , the top and bottom end caps  14  and  16  are provided with molded cavities  26  and  28  that are shaped to receive an item to be held in the package  10 . It will be appreciated that cavities  26  and  28  may be freely modified to accommodate differently shaped items. 
         [0052]      FIGS. 2 through 7  show additional views of the package  10  shown in  FIG. 1 .  FIGS. 2 and 3  show, respectively, front and rear views of the package.  FIGS. 4 and 5  show left and right side views of the package  10 .  FIGS. 6 and 7  show top and bottom views of the package  10 . 
         [0053]      FIGS. 8 and 9  show elevation views of the upper and lower end caps  14  and  16 . Each end cap  14  and  16  is a rigid body that may suitably be fabricated, for example, using an injection molding technique. Suitable materials for the end caps include PVC, polypropylene, polyethylene, and polystyrene. 
         [0054]    The upper end cap  14  shown in  FIG. 8 , as mentioned above, provides a releasable locking mechanism for securing the end cap  14  to the sleeve. The releasable locking mechanism includes a pair of rectangular channels  22  on opposite sides of the end cap  14 . The pair of channels  22  is positioned to receive a corresponding pair of locking tabs  18  extending from the sleeve  12 . The upper side of each channel  22  is defined by a rim  30  that is dimensioned to be slightly larger than the upper opening of the sleeve  12 , and to engage the upper sleeve end to prevent the end cap  14  from being inserted too far into the sleeve opening. The lower side of each channel  22  is defined by a ledge  34 , which provides a surface for engaging a locking edge of each upper locking tab  18 . 
         [0055]    The lower end cap  16  shown in  FIG. 9  provides a non-releasable locking mechanism for securing the lower end cap  16  in the lower opening of the sleeve  12 . The non-releasable locking mechanism includes a single channel  24  encircling the end cap  16 . The lower side of the channel  24  is defined by a rim  32  that is dimensioned to be larger than the bottom sleeve opening. The upper side of the channel  24  is defined by a ledge  36  that provides a surface for engaging a locked edge of each lower locking tab  20  extending from the sleeve  12 . 
         [0056]    The operation of the locking and release mechanisms is now described with respect to an exemplary container and exemplary fabrication technique. It will be apparent that the described container and fabrication technique may be modified without departing from the spirit of the invention.  FIG. 10  shows a plan view of a blank  100  for forming a sleeve according to an aspect of the invention. The blank  100  is die cut from a sheet of suitable material, such as PVC, APET, or PETG. If desired, textual or graphic matter may be printed directly onto the blank using a high-speed printing process. 
         [0057]    A series of score lines  102  is fabricated into the blank  100  to divide the blank into a number of panels and tabs. The blank  100  includes a first panel  104  and a second panel  106  that are folded towards each other to form the body of the finished sleeve. A glue flap  108  extends upward from the first panel  104 , opposite the second panel  106 , and is used to attach the outside edges of the first and second panels  104  and  106  to each other. As shown, the tear strip  52  and tab  50  are manufactured on the first panel  104 . 
         [0058]    Extending from the right side of each of the first and second panels  104  and  106  is a releasable locking tab  110  and  112 . According to an aspect of the invention, the releasable locking tabs  110  and  112  are trapezoidal in shape. As discussed below, other shapes may be used for the releasable locking tabs  110  and  112 . 
         [0059]    Non-releasable locking tabs  114  and  116  extend from the left side of the first and second panels  104  and  106 . According to an aspect of the invention, the non-releasable locking tabs  114  and  116  are rectangular in shape. Each of the locking tabs  110  includes a respective locking edge  120 ,  122 ,  124  and  126  that, as described below, engages a ledge in an end cap, such as ledge  156  in end cap  150  illustrated in  FIGS. 13A-D  and described below, to lock the end caps in position in the sleeve ends. 
         [0060]    It will be seen that when the second panel  106  is folded over the first panel  104 , locking tabs  112  and  116  will line up with locking tabs  110  and  114 . However, other orientations for the locking tabs  110 ,  112 ,  114  and  116  may also be used without departing from the spirit of the invention. 
         [0061]    In fabricating a finished sleeve from the blank  100 , the second panel  106  is folded over the first panel  104 . The partially folded blank  100  is shown in  FIG. 11 . The glue flap  108  is then folded over the second panel  106 , and a suitable technique is employed to cause the glue flap  108  to adhere to the second panel  106  at the cross-hatched regions  128  and  130 . It will be seen that the bonding of the glue flap  108  to the second panel  106  creates a tube with openings at the left and right of the blank  100 . 
         [0062]    Prior to the attachment of the end caps, the locking tabs  110 ,  112 ,  114  and  116  are folded inward towards the interior of the sleeve.  FIG. 12A  shows a plan view of the finished sleeve  100 , and  FIG. 12B , not drawn to scale, shows a right side view of the sleeve  100 . The sleeve  100  may be readily popped opened for insertion of the end caps by applying gentle pressure to the sleeve in the direction of the arrows  132  shown in  FIG. 12B . 
         [0063]    Depending on the dimensions of the finished sleeve  100 , it would be possible for a worker to hold the sleeve  100  in one hand, using the thumb and fingers to apply pressure to the side edges of the sleeve  100 . The worker could then pop the sleeve  100  open, and use the other hand to install an end cap into one of the two sleeve openings. Once the first end cap has been installed, the package is relatively stable, and can be stood on end, with the installed end cap acting as a base. Product can then be loaded through the other opening. If necessary, further pressure can be applied to the side edges of the sleeve to open the other opening for loading of the product and installation of the second end cap. The above described manual operations may also be performed by machine. 
         [0064]    Once the package has been loaded and closed, it would still be possible to adjust or rework the contents of the package by using the twist-off release mechanism described below to remove the releasable end cap without damaging the sleeve. 
         [0065]    As mentioned above, it would also be possible to use releasable end caps at both openings of the sleeve, or non-releasable end caps at both openings. Also, in a container having one releasable end cap and one non-releasable end cap, it would be possible to use the releasable cap as the top cap or the bottom cap, as desired. 
         [0066]      FIGS. 13A-D  are cross section diagrams of an exemplary end cap  150  and sleeve end  170  illustrating the operation of a locking mechanism according to an aspect of the invention. The drawing of sleeve end  170  includes a broken line  172 , which represents the perimeter of the sleeve opening. 
         [0067]    As described above, the sleeve end  170  includes a pair of locking tabs  174 . The locking tabs  174  extend upward from the sleeve  176 . Prior to the installation of the end cap  150 , the locking tabs  174  are folded into the sleeve opening, towards the inner surface of the sleeve  176 . However, because of the resilience of the material used to fabricate the sleeve  176  and locking tabs  174 , the locking tabs  174  have a tendency to unfold slightly. The slight unfolding of the locking tabs  174  has been exaggerated in  FIGS. 13A-D  for purposes of illustration. The unfolding of the locking tabs  174  is useful in ensuring a firm locking action. 
         [0068]    The locking cap  150  includes a channel  152  at each side corresponding in position to the locking tabs  174 . The channels  152  are not drawn to scale. As discussed above, in a non-releasable end cap, a single channel encircles the perimeter of the end cap. In a releasable end cap, separate channels are provided, corresponding in position to each of the locking tabs  174 . However, in either type of end cap, the initial locking action is substantially similar. 
         [0069]    The upper boundary of the channel  152  is defined by a rim  154  that, when the end cap  150  is seated in the sleeve end  170 , overhangs the sleeve end  170  to prevent the end cap  150  from being further inserted into the sleeve end. The channel  152  further includes a ledge  156  that engages a locking edge of each of the locking tabs  174 . Although the channel  152  is shown as having a rectangular profile, other channel profiles may also be used. For example, it may be desirable for the ledge to define a more acute angle, or for the channel to be deeper. The ledge face  158  is dimensioned and shaped to fit closely within the sleeve. 
         [0070]      FIG. 13B  shows the end cap  150  that has been partially inserted into the sleeve end  170 . As shown in  FIG. 13B , the bottom circumference of the end cap  150  urges the locking tabs  174  downward, towards the inner walls of the sleeve  176 . In  FIG. 13C , as the end cap  150  continues to be advanced downward, the locking tabs  174  are pressed against the inner walls of the sleeve  176 . In  FIG. 13D , when the end cap  150  reaches its final position, the locking tabs  174 , because of their resiliency, tend to unfold slightly, causing the locking tabs  174  to open up into the channel  152 . The slight unfolding of the locking tabs  174  causes the locking edges of the locking tabs  174  to engage the ledge surface  156 , thereby preventing the end cap from being pulled upward out of the sleeve opening. Where the end caps have a convexly curved outer perimeter, the insertion of the end cap into the sleeve causes corresponding curves to form in the sleeve  176  and locking tabs  174 . This curvature tends to increase the strength of the locking tabs  174 . 
         [0071]      FIGS. 14 and 15  show cutaway views of a package  200  according to an aspect of the invention.  FIG. 14  shows a close-up view of a portion of the package  200  illustrating a single locking tab  202  seated in a channel  204 .  FIG. 15  shows a cutaway of the whole package  200  illustrating a pair of lower locking tabs  202  and a pair of upper locking tabs  206 . 
         [0072]      FIGS. 16A-D  and  17 A-D illustrate the operation of a release mechanism  250  according to an aspect of the invention.  FIG. 16A  shows a diagram of a releasable locking tab  252  seated within a rectangular channel  254  in a finished package. For the purposes of discussion, an upper end cap is shown. As discussed above, the upper edge of the channel  254  is defined by the end cap rim, and the lower edge of the channel is defined by a ledge. The left and right edges of the channel are defined by surfaces  256  that are substantially continuous with the ledge face. 
         [0073]    As described above, the releasable locking tab  252  has a trapezoidal shape. Thus, as the locking tab  252  is urged against a side edge  258  of the channel, it will be seen that an acute vertex  260  is presented to the side edge  258 . The acute vertex  260  allows the locking tab  252  to ride up the side edge  258  of the channel  254  and onto surface  256 , starting with the point of the vertex  260 . The movement of the locking tab  252  onto surface  256  can be seen in  FIGS. 17A-D . 
         [0074]    Because the sleeve is flexible and resilient, the end cap can be freely twisted within the sleeve opening, even when the end cap does not have a circular perimeter. Twisting the end cap causes a movement of the channel relative to the tab. As described above, this movement causes the locking tab to ride up onto a surface next to the channel, causing the locking tab to become disengaged from the channel and ledge. The disengagement of the locking mechanism is illustrated in  FIGS. 18A and 18B . In  FIG. 18A , each locking tab  252  is seated in a channel  254 . In  FIG. 18B , after the locking cap  262  has been twisted, the locking tabs  252  are no longer in the channels  254 . The end cap can now be removed. The twist angle required to disengage the end cap  262  from the sleeve  264  can be adjusted by adjusting the dimensions of the channels  254 , the locking tabs  252 , or both. 
         [0075]    It would be possible to create a one-way release mechanism, in which the end cap can be released only by twisting it in one direction. The one-way release mechanism could be accomplished, for example, by using a locking tab having a first side with an acute vertex, and a second side with square vertices. It would be difficult, if not impossible, to twist the end cap off in the direction of the square vertices. 
         [0076]      FIGS. 19A-D  and  FIG. 20A-D  illustrate an alternative release mechanism. According to this aspect of the invention, a rectangular locking tab  272  may be used. As shown in  FIGS. 20A-D , one side of the channel  274  is provided with a ramp  276  leading up to surface  278 . When the end cap is twisted, the locking tab  272  rides up the ramp  276  and onto surface  278  to disengage the locking mechanism. In this example, only one ramp  276  is provided. Thus, the locking mechanism can only be released by twisting the end cap in the direction of the ramp  276 . If desired, a second ramp can be added to the other side of the channel  274  to allow the locking mechanism to be released by twisting the end cap in either direction. 
         [0077]    It should be noted that it would be possible to use other configurations of locking tabs and channels without departing from the spirit of the invention. For example, it would be possible to use more than two locking tabs per opening. Also, different shapes may be used for the end caps and the sleeve. 
         [0078]      FIGS. 21 through 27  show a product package  300  according to another aspect of the invention. In this package  300 , a releasable end cap  302  is provided at the bottom end of sleeve  304 , and a non-releasable cap  306  is provided at the top of the sleeve. The end caps  302  and  306  have been shaped to receive a different product, such as a bottle containing lotion or fragrance.  FIGS. 22 and 23  show front and rear views of the package  300 .  FIGS. 24 and 25  show left and right side views.  FIGS. 26 and 27  show top and bottom views of the package  300 . 
         [0079]      FIGS. 28 through 33  show another package  350  according to an aspect of the invention.  FIG. 28  shows a perspective view of the package  350 . As shown in  FIG. 28 , the channels  352  in the end caps  354  are not rectangular, but instead are angled.  FIGS. 29 and 30  show front and rear views of the package.  FIGS. 31 and 32  show left and right side views, and  FIG. 20  shows a top view. 
         [0080]    While the foregoing description includes details which will enable those skilled in the art to practice the invention, it should be recognized that the description is illustrative in nature and that many modifications and variations thereof will be apparent to those skilled in the art having the benefit of these teachings. It is accordingly intended that the invention herein be defined solely by the claims appended hereto and that the claims be interpreted as broadly as permitted by the prior art. 
         [0081]    All patents, patent applications, and published references cited herein are hereby incorporated by reference in their entirety. It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.