Abstract:
Collapsible household containers having a foldable wall section with shape-retaining characteristics are disclosed. In particular, collapsible laundry baskets, buckets, colanders, dish drainers, and cups are provided. The folding region may include foldable tiers of a flexible material, each tier having at least one stable, relatively expanded position and at least one stable, relatively collapsed position; and an intervening, non-folding tier composed of a different, relatively rigid material.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to German patent application DE 20 2014 101 047.5, filed Mar. 10, 2014, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to collapsible containers. More particularly, open-top, shape-retaining collapsible containers or vessels for kitchen and home use are provided, including laundry baskets, buckets, and colanders, with improved structural strength in a collapsible region compared to existing collapsible containers. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is desirable for a household container to be able to collapse to relatively compact dimensions for storage or transport when the container is either not in use or being used to hold less than its maximum volume capacity of contents. Collapsible kitchenware and houseware containers of various types exist to accommodate these general needs. For example, one type of existing collapsible colander includes a stiff or rigid top section connected to a stiff or rigid bottom section by a foldable wall section that snap-folds between or among two or more positions, including at least a fully expanded position and a fully collapsed position, and in some instances, one or more intermediate, partially collapsed positions. However, because the material used to make the foldable wall section must be flexible enough to fold, it typically offers little or no resistance to deformation caused by lateral forces, such as an object bumping into or pressing against the side of the container, or a user attempting to grasp or lift the container by the flexible wall section, which could result in the contents being damaged, undesirably shifted, or spilled. 
         [0004]    A need therefore exists for kitchenware and houseware containers that are collapsible and expandable; self-supporting in at least a fully collapsed and a fully expanded state, if not in one or more intermediate, partially expanded states; and resistant to structural deformation over at least a portion of a collapsible wall region. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The present invention provides improved collapsible household containers and methods of making them. According to one aspect of the invention, a collapsible container is provided, comprising a generally annular top tier; a bottom tier including a generally horizontal support surface; and a collapsible wall section connecting the top tier to the bottom tier, the collapsible wall section including at least three stacked, generally annular tiers, at least a middle one of which is rigid, being formed of a different material than adjacent flexible tiers disposed above and below the middle tier. The top and bottom tiers of the container may also be rigid and formed of a different material than the flexible tiers of the collapsible wall section. The collapsible wall section, top tier, and bottom tier collectively define a container body having a top opening, a generally closed bottom comprising the generally horizontal support surface of the bottom tier, and a generally closed periphery comprising at least a part of the top tier and at least a part of the collapsible wall section. The flexible tiers are configured to fold between relatively expanded and relatively collapsed positions. The size of the container volume can be increased by folding at least one of the flexible tiers from a relatively collapsed to a relatively expanded position and can be decreased by folding at least one of the flexible tiers from a relatively expanded to a relatively collapsed position. Preferably, the flexible tiers are stable in relatively expanded positions and relatively collapsed positions, so that the container is self-supporting in each of its relatively expanded and relatively collapsed states. 
         [0006]    Preferably, to facilitate snap-through movement between the folded and unfolded states, each flexible tier is provided with two living hinges comprising very narrow annular bands of flexible material, at which the material suddenly tapers down to a sharply reduced thickness, at the top and bottom ends of the flexible tier. Beyond the ends of the flexible tier, the material suddenly tapers back out to an increased thickness, and a wider (i.e., taller) band of the flexible material of increased thickness is disposed between each living hinge and the adjacent rigid tier of a different material, where applicable. In addition to facilitating snap-through movement between states, the thinned regions also permit each flexible tier to fold more compactly against adjacent tiers, promote stability in the folded state by minimizing forces tending to straighten the material at the bent region, and promote the formation of a folded crease at a precise, consistent location each time the tier is folded. 
         [0007]    In certain embodiments, which correspond to methods of making containers according to another aspect of the invention, the middle tier is composed of a polypropylene, metal, or nylon material, and the flexible tiers are composed of a silicone material or a thermoplastic elastomer. For example, flexible thermoplastic elastomer tiers may be connected to the rigid middle tier by overmolding. Optionally, and particularly in the case of a metal or nylon rigid tier, the connection between the rigid tier and an adjacent flexible tier (for example made of silicone) may be strengthened by adhesive material disposed in adhesive contact with a surface of the middle tier and an adjacent surface of the flexible tier. Alternatively, other suitable means such as mechanical fasteners may be employed to connect a rigid tier to an adjacent flexible tier. 
         [0008]    In some embodiments, each tier of the container is at least substantially imperforate, so that the container can serve to hold liquid. In other embodiments, the container has perforations serving to drain liquid and/or facilitate aeration, as in colanders, dish drainers, buckets adapted as sand sifters, and certain embodiments of laundry baskets. 
         [0009]    In still other embodiments, at least a portion of at least one of the tiers is air permeable to permit some airflow into and out of the container without passing through the top opening. 
         [0010]    In yet other embodiments, the top tier comprises at least one attached handle. 
         [0011]    According to another aspect of the invention, a collapsible dish drainer is provided having a collapsible wall structure generally as described above. The bottom tier of the drainer includes a generally horizontal support surface with a drain and a plurality of parallel, upstanding partitions arranged to support dishware standing on edge between adjacent partitions. Advantageously, said drain is configured to be plugged by an insertable drain plug to render the body of the drainer at least substantially watertight. Together with the drainer, a separate, collapsible domed lid may be provided. The domed lid may have a substantially similar structure to that of the drainer itself, but slightly smaller and imperforate, while also including a handle set into a generally horizontal panel of its top tier. The lid is configured to be supported on said top drainer tier in a mating configuration with the top tier of the drainer, whether the collapsible lid is oriented right-side-up (i.e., with its opening facing down) or upside-down. When upside-down, the collapsible lid is configured to nest inside the drainer body, at or below the highest portion of the top drainer tier and at least substantially within the interior volume below the drainer top opening, when the drainer and the lid are both in fully expanded states. Then, the lid is configured to collapse together with the drainer, remaining at or below the highest portion of the drainer top tier and at least substantially within the drainer volume when the drainer and the lid are both in fully collapsed states. 
         [0012]    According to yet another aspect of the invention, a collapsible cup is provided. The collapsible cup may advantageously be used as a drinking cup or a measuring cup, for example. The collapsible cup includes a collapsible wall structure, substantially as described above, and a handle pivotally connected to its top tier. When the cup is fully collapsed, the handle is configured to pivot into a position in which a portion of the handle extends beneath and generally parallel to the bottom tier of the cup. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of a collapsible laundry basket according to one aspect of the invention, in a fully expanded state. 
           [0014]      FIG. 2  is a perspective view of the laundry basket shown in  FIG. 1 , in a fully collapsed state. 
           [0015]      FIG. 3  is a side elevation view of the laundry basket shown in  FIG. 1 , in a fully collapsed state. 
           [0016]      FIG. 4  is a fragmentary cross-sectional view of a wall structure of the laundry basket shown in  FIG. 1 , in a partially collapsed state. 
           [0017]      FIG. 5  is a fragmentary cross-sectional view of a wall structure of the laundry basket shown in  FIG. 1 , in another partially collapsed state. 
           [0018]      FIG. 6  is a perspective view of a collapsible bucket according to another aspect of the invention, in a fully expanded state. 
           [0019]      FIG. 7  is a perspective view of the bucket shown in  FIG. 1 , in a fully collapsed state. 
           [0020]      FIG. 8  is a side elevation view of the bucket shown in  FIG. 1 , in a fully collapsed state. 
           [0021]      FIG. 9  is a perspective view of a collapsible colander according to another aspect of the invention, in a fully expanded state. 
           [0022]      FIG. 10  is a perspective view of the collapsible colander shown in  FIG. 9 , in a fully collapsed state. 
           [0023]      FIG. 11  is a side elevation view of the collapsible colander shown in  FIG. 9 , in a fully collapsed state. 
           [0024]      FIG. 12  is a perspective view of a collapsible cup according to still another aspect of the invention, in a fully expanded state. 
           [0025]      FIG. 13  is a perspective view of the cup shown in  FIG. 12 , in a fully collapsed state. 
           [0026]      FIG. 14  is a side elevation view of the cup shown in  FIG. 12 , in a fully collapsed state. 
           [0027]      FIG. 15  is a bottom perspective view of the cup shown in  FIG. 12 , in a fully collapsed state. 
           [0028]      FIG. 16  is a top perspective view of a collapsible dish drainer according to yet another aspect of the invention, in a fully expanded state. 
           [0029]      FIG. 17  is a top perspective view of the dish drainer shown in  FIG. 16 , in a fully collapsed state. 
           [0030]      FIG. 18  is a side elevation view of the dish drainer shown in  FIG. 16 , in a fully expanded state. 
           [0031]      FIG. 19  is a side elevation view of the dish drainer shown in  FIG. 16 , in a fully collapsed state. 
           [0032]      FIG. 20  is a bottom perspective view of the dish drainer shown in  FIG. 16 , in a fully collapsed state. 
           [0033]      FIG. 21  is a top perspective view of the dish drainer shown in  FIG. 16 , having a collapsible lid placed thereon, the lid in a fully expanded state. 
           [0034]      FIG. 22  is a top perspective view of the dish drainer shown in  FIG. 16 , having a collapsible lid placed thereon, the lid in a fully collapsed state. 
           [0035]      FIG. 23  is a side elevation view of the dish drainer shown in  FIG. 16 , having a collapsible lid placed thereon, the lid in a fully expanded state. 
           [0036]      FIG. 24  is a top perspective view of the dish drainer shown in  FIG. 16 , having an upside-down collapsible lid nested therein, both drainer and lid in fully expanded states. 
           [0037]      FIG. 25  is a top perspective view of the dish drainer shown in  FIG. 16 , having an upside-down collapsible lid nested therein, drainer and lid in fully collapsed states. 
           [0038]      FIG. 26  is a side elevation view of the dish drainer shown in  FIG. 16 , having an upside upside-down collapsible lid nested therein, drainer and lid in fully collapsed states. 
           [0039]      FIG. 27  is a side elevation view of the dish drainer shown in  FIG. 16 , having an upside-down collapsible lid nested therein, both drainer and lid in fully expanded states. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0040]    Collapsible kitchenware and houseware containers with improved shape retention and structural integrity in accordance with the present invention are described in this section, with reference to a collapsible laundry basket  10  depicted in  FIGS. 1-5 , a collapsible bucket  26  depicted in  FIGS. 6-8 , a collapsible colander  42  depicted in  FIGS. 9-11 , a collapsible cup  58  depicted in  FIGS. 12-15 , and a collapsible drainer  78  depicted in  FIGS. 16-27 . 
         [0041]    Turning to  FIGS. 1-5 , a laundry basket  10  according to one embodiment of the invention are described and illustrated. Laundry basket  10  includes a rigid top tier  12 , a rigid bottom tier  14 , and a collapsible wall section  16  that may be collapsed and expanded to vary the overall height dimension of laundry basket  10  and thus the available volume for laundry. Wall section  16 , in turn, includes a rigid middle tier  18  between two flexible tiers  20  and  22 . Additional tiers may be included in the collapsible wall section, preferably adhering to the alternating arrangement in which a flexible tier is connected above and below each rigid tier. 
         [0042]    Optionally but preferably, laundry basket  10  includes integrally formed or otherwise connected or attached handles, such as handles  24  shown as being integral to top tier  12 . Additional lower handles may be formed as slot openings in middle tier  18 . Also, the body of laundry basket  10  may include lateral openings (not shown) to allow its contents to air out, as is particularly beneficial when laundry basket  10  is used as a hamper for dirty laundry. The lateral openings may be formed in rigid middle tier  18  and/or in any flexible tier. 
         [0043]    Flexible tiers  20  and  22  are illustrated as having two stable positions, one unfolded and one folded, respectively corresponding to relatively expanded and collapsed states of laundry basket  10 . A fully expanded state of laundry basket  10  is illustrated in  FIG. 1 , showing both flexible tiers  20  and  22  in their unfolded positions, while a fully collapsed state of laundry basket  10  is illustrated in  FIGS. 2 and 3 , showing both flexible tiers  20  and  22  in folded positions. In its fully expanded state, laundry basket  10  provides its maximum laundry volume capacity, while in its fully collapsed state, laundry basket  10  is at its most compact, which is particularly beneficial for storage. 
         [0044]    Two partially collapsed states of laundry basket  10  are illustrated by the fragmentary side sectional views shown in  FIGS. 4 and 5 , in which only flexible tier  20  or only flexible tier  22  is folded, respectively. Thus, it is illustrated that each of flexible tiers  20  and  22  may be folded and unfolded separately and independently to transform the shape of laundry basket  10  to its fully expanded, fully collapsed, and two partially expanded states illustrated in the Figures. Multiple advantages are provided by the partially collapsed states of laundry basket  10 . For instance, when filling a laundry basket with clean laundry, it is often convenient to place the basket on a high surface near a dryer containing a load of clean laundry. The partially collapsed position of laundry basket  10  facilitates this process by making it easier to reach clean clothes over the top of laundry basket  10 . In addition, when carrying a volume of laundry smaller than the maximum capacity of laundry basket  10 , partially collapsing laundry basket  10  may make it more comfortable to carry. For example, when holding laundry basket  10  from underneath by bottom tier  14 , laundry basket  10  will be easier to see over or around if in its collapsed state. On the other hand, when walking while holding laundry basket  10  by handles  24 , partially collapsing laundry basket  10  may help to prevent one&#39;s knees from bumping into laundry basket  10 , without having to hold the handles of laundry basket  10  as high as would be necessary if it were fully expanded. Lower handles formed in middle tier  18  (not shown), for example in the form of elongate slots with rounded ends, may also assist in this regard, whether or not laundry basket  10  is fully expanded. 
         [0045]    With reference to  FIGS. 6-8 , a collapsible bucket  26  according to the invention is illustrated. Bucket  26  includes a rigid top tier  28 , a rigid bottom tier  30 , and a collapsible wall section  32  including a rigid tier  34  disposed between flexible tiers  36  and  38 . The fully expanded, fully collapsed, and partially collapsed states of bucket  26 , illustrated in the drawings, are substantially analogous to those of laundry basket  10 . Optionally, but preferably, bucket  26  includes a handle  40  connected to its top tier. Unlike laundry basket  10 , which may advantageously include perforations to facilitate aeration, the body of bucket  26  is preferably imperforate so as to retain water or other liquid, although in certain embodiments not shown, bucket  26  may include a perforated bottom, for example, to serve as a sand-sifter for beach or sandbox amusement. Advantageously, when bucket  26  is filled with liquid, the collapsing action of wall section  32  provides a way of emptying at least some of the liquid contents, by simply pressing down on top tier  28  to cause wall section  32  to collapse, allowing the liquid to overflow. This avoids the need for lifting and/or inverting bucket  26 , at least until the liquid level is lower, making those steps less strenuous. 
         [0046]    Turning to  FIGS. 9-11 , a collapsible colander  42  embodying another aspect of the invention is illustrated. Colander  42  includes a rigid top tier  44 , a rigid bottom tier  46 , and a foldable wall section  48  comprising at least one rigid middle tier  50  and at least two flexible tiers  52  and  54  above and below middle tier  50 . Bottom tier  46  includes perforations  56  typically to facilitate draining water from rinsed salad greens, boiled pasta noodles, or other damp foods, as well as cooperating with tiers  54 ,  50 ,  52 , and/or  44  to form a concave, curved surface to facilitate overturning contents. As in the other collapsible containers according to the invention, fully expanding collapsible colander  42  provides its maximum volume capacity, while fully collapsing it provides for most compact storage. In the case of collapsible colander  42  one benefit of a partially collapsed state may be to minimize the refrigerator space occupied by a leftover salad or other dish prepared, and conveniently put away, in colander  42 . 
         [0047]    With reference to  FIGS. 12-15 , collapsible cup  58  embodying another aspect of the invention is illustrated. Cup  58  includes a body portion  60  comprising rigid top tier  62 , a rigid bottom tier  64 , and a foldable wall section  66  comprising at least one rigid middle tier  68  and at least two flexible tiers  70  and  72  above and below middle tier  68 . As in the other collapsible containers according to the invention, fully expanding collapsible cup  58  provides its maximum volume capacity, while fully collapsing it provides for most compact storage. Cup  58  also includes a handle  74  pivotally connected to top tier  62  for movement between a use position shown in  FIG. 12  and a compact or stowed position shown in  FIGS. 13-15 . It will be understood from  FIGS. 12-15  that cup  58  must be collapsed before folding handle  74  to the stowed position, and conversely, handle  74  must be moved to the use position before expanding cup  58 . Preferably, a suitable mechanism is provided for resisting movement of handle  74  away from the use position, so that the weight of liquid contained in cup  58  does not cause body portion  60  of cup  58  to pivot towards handle  74  when cup  58  is held by the handle, resulting in user annoyance and/or possible spillage. Examples of suitable mechanisms may include a detent for “snapping” handle  74  into and out of the use position and/or a tight-fitting pivot joint  76  providing frictional resistance over its full range of motion or only a partial range of motion near the use position. A similar retention mechanism may also be provided for keeping handle  74  in the stowed position. As an ancillary benefit, should flexible tiers  70  and  72  of foldable wall section  66  exhibit some degree of hysteresis, for example tending to spontaneously unfold when cup  58  is collapsed after being kept continuously in its fully expanded state for a long period of time, a retention mechanism for holding handle  74  in its stowed position may also help to retain body portion  60  of cup  58  in its fully collapsed state until the material of flexible tiers  70  and  72  returns to its normal behavior. 
         [0048]    Turning to  FIGS. 16-27  a collapsible dish drainer  78  embodying another aspect of the invention is illustrated. Dish drainer  78  includes a drainer body  80  comprising rigid top tier  82 , preferably including a rim with a downturned portion defining a peripheral channel  83  for ease of lifting, as shown in  FIG. 20 ; a rigid bottom tier  84 , and a foldable wall section  86  comprising at least one rigid middle tier  88  and at least two flexible tiers  90  and  92  above and below middle tier  88 . As in the other collapsible containers according to the invention, fully expanding collapsible dish drainer  78  provides its maximum volume capacity, while fully collapsing it provides for most compact storage. Dish drainer  78  includes an array of upstanding slender partitions  94  whose gap spacing, individual length, individual height, and other relevant dimensions are suited for retaining typically sized plates, bowls, and other dishes on edge between pairs of adjacent partitions  94  Additionally, although the spacing between partitions  94  in the illustrated embodiment of drainer  78  is generally uniform, multiple arrays of partitions having distinct spacing and/or individual dimensions may instead be provided as appropriate to accommodate differently shaped individual dishes or sets of dishes. 
         [0049]    Dish drainer  78  also includes a perforated drain  96  to permit water drained from dishes in drainer  78  to drain out, for example into a sink or wash basin. Perforations  98  of drain  96  are set at the bottom surface of a depression having an imperforate wall section  100 . As best seen in the side elevation views of drainer  78  (such as  FIG. 18 ), the shape of bottom tier  84  is such that when its lowest portion rests on a horizontal surface to support drainer  78 , the bottom of drain  96  is raised above the horizontal surface to permit free draining flow through perforations  98  and to inhibit soiling of drain  96 , either by contact of drain  96  with the horizontal surface itself, or by backflow of accumulated liquid on the horizontal surface (such as the bottom of a sink basin) through perforations  98 . Drain wall section  100  has a slight inward taper toward the bottom surface of the depression to facilitate covering and sealing drain  96  with a resilient drain plug  102 . Advantageously, this permits drainer  78  to perform the additional function of a dish pan for soaking and/or hand washing dishes, while in its expanded state and having drain plug  102  inserted, as in the configuration illustrated in  FIG. 16 . However, as an alternative to the illustrated drainer  78  having a localized drain  96 , it will be understood that a dish drainer having perforations extending across its entire bottom surface (not shown in the Figures) may have its own advantages, such as more rapid and/or complete draining of water from the interior surfaces of the drainer body, and/or better aeration to facilitate faster evaporation of water from the dishes and drainer. 
         [0050]    Optionally but advantageously, drainer  78  may be provided together with a complementary lid. In particular, a lid  104  may be provided which is also collapsible, including a stiff or rigid panel  106 , a foldable wall section  108 , and a stiff or rigid rim  110 . Foldable wall section  108  of lid  104  is illustrated in the Figures as being entirely composed of a resilient, flexible material, including flexible tiers  112 ,  114  and a middle, stiff tier  116  that is made thicker and/or less tapered than flexible tiers  112 ,  114 , so as to retain its orientation when flexible tiers  112 ,  114  fold relative to it. Rim  110  of lid  104  is sized to nest in a stepped portion  118  of drainer top tier  82  shown in  FIGS. 16 and 17 , in both a right-side-up orientation as shown in  FIGS. 21-23  and an upside-down orientation as shown in  FIGS. 24-27 . Likewise, when collapsible lid  104  is first nested upside down in collapsible drainer  78 , both lid  104  and drainer  78  being initially fully expanded (see  FIG. 24 , and the side elevation view of  FIG. 27 , which also illustrates that lid  104  fits entirely below the highest portions of drainer top tier  82 ), foldable lid wall section  108  is configured to collapse together with foldable drainer wall section  86  in a nested configuration illustrated in  FIGS. 25 and 26 , achieving the same contraction of the height dimension of drainer  78  as when drainer  78  is collapsed by itself. 
         [0051]    Drainer  78  has several different use configurations, making it adaptable to different circumstances and user preferences, as well as different uses. For example, it has already been noted that drainer  78  may also serve as a dish pan for soaking and hand washing, when in an expanded state and having drain plug  102  inserted. When drainer  78  is employed in this way (or in any other configuration without lid  104  placed thereon), lid  104  in its upside-down, expanded configuration may simultaneously be used as another slightly smaller dish pan independent of drainer  78 , for example to provide more volume for simultaneous soaking of more dishes. Alternatively, lid  104  may be placed over drainer  78  in its right-side-up orientation, either expanded (to provide more height clearance for tall dishes) or collapsed (for a more compact vertical profile), for example as desired for the purpose of protecting dishes in drainer  78  from inadvertent soiling or contamination while they are being soaked, as shown in  FIGS. 21-23 . To facilitate easy removal of lid  104 , an inset handle  120  may be provided on the top side of lid panel  106 . 
         [0052]    When used for draining water from damp, clean dishes, on the other hand, drainer  78  may either be in a collapsed or an expanded state. The collapsed state provides the most unobstructed access to the bottom tier  84  of drainer  78 , which may be particularly desirable for repetitive loading of dishes thereon from a lateral location, such as from a kitchen sink next to a counter (not shown) on which drainer  78  is placed, after washing each dish in the sink. (In such a situation, although not illustrated in the Figures, a conventional dish drainer tray, having three raised sides and one draining side placed over an edge of the sink, may beneficially be placed on the counter underneath drainer  78  to direct water drained from drainer  78  into the sink.) On the other hand, the expanded state of drainer  78  makes use of foldable wall section  86  and top tier  82  as partial splash guards to protect dishes from being soiled by splashing from lateral directions, which may likewise be desirable in the aforementioned situation of washing dishes in an adjacent sink while clean dishes are held in drainer  78 . Alternatively, omnidirectional splash protection for dishes in drainer  78  may be provided by placing lid  104  over drainer  78 , either in its expanded position shown in  FIGS. 21 and 23  (again, to accommodate tall dishes or utensils, for instance), or its collapsed position shown in  FIG. 22 . 
         [0053]    Still another function of drainer  78  with lid  104  placed on it may be to protect dishes placed in drainer  78  for transportation and/or storage. In this context, lid  78  may both help to keep airborne particles from entering drainer  78  and settling on dishes stored therein, but also may permit boxes, containers, or other items to be conveniently stacked on top of drainer  78  without resting directly on the dishes. 
         [0054]    Of course, in the context of containers according to the present invention, as in common parlance, it will be understood that “stiff,” “rigid,” and “flexible” are relative terms. Thus unless further specified, referring to a tier of a wall structure as “stiff” herein simply means, at a minimum, that the tier is stiff enough to impart a force to its neighboring flexible tier or tiers sufficient to fold the flexible tier or tiers between relatively folded and unfolded stable positions (optionally causing the flexible tiers to “snap” between positions), without itself folding (i.e., without inverting its vertical orientation, with respect to the top and bottom of the container). On the other hand, a tier that is considered “rigid” for purposes of the invention typically will not even appreciably yield or deform, let alone fold, in the direction of the force imparted to fold the flexible tiers, in response to either that force or other typical loads associated with normal use of the container. Still further, a rigid tier preferably will not appreciably deform in any direction during normal use of the container. A “rigid” tier that exhibits the latter characteristic of not appreciably deforming in any direction is typically formed of a different material than the flexible tiers, rather than the same material in a different size or geometric configuration. 
         [0055]    Although each flexible tier of the various household containers described herein is illustrated as having only two stable positions, it is also within the scope of the invention to provide one or more flexible tiers having a plurality of stable partially expanded positions, for example by providing one or more flexible tiers having a stepped profile comprising a series of accordion-like pleats of flexible material, the pleats comprising peripheral bands of material oriented in alternating directions and connected to adjacent bands by living hinges, so that each pleat can be independently folded and unfolded (not shown), being stable in either state. Also, a wall structure of a container according to the invention need not have the exact shapes of the containers shown in the Figures, but may have any suitable shape, such as round, oval, rectangular with rounded corners, or other shape as desired. For example, successive accordion pleats may be stable in relatively “bent” orientations, in which part of the circumferential length of a pleat is folded and the remainder of the length is unfolded. 
         [0056]    Household containers according to the invention may be constructed of any suitable materials that impart relative stiffness or rigidity to the top tier, middle tier, and bottom tier; and relative flexibility to the flexible tiers, while permitting the tiers to be durably attached to their neighboring tiers. For example, the top tier, bottom tier, and/or middle tier may be composed of polypropylene, the flexible tiers being a thermoplastic elastomer overmolded onto the polypropylene. Alternatively, the top tier, bottom tier, and/or middle tier may be composed of metal or nylon, the flexible tiers being a silicone material overmolded onto the metal or nylon with adhesive glue between the two materials to strengthen their connection. 
         [0057]    With the exception of lid  104  of collapsible dish drainer  78  (which may itself serve as a collapsible container independently of drainer  78 ), the middle tiers of the foldable wall sections of the various illustrated containers according to the present invention are shown and described above as being of a rigid material that is different from the flexible material of the adjoining flexible tiers. However, the structural strength and shape retention provided by a rigid middle tier of a different material is only one of many advantages provided by household containers of the present invention, and where desired, components that are merely “stiff,” and optionally made of the same material as the flexible tiers, but formed with shapes and/or dimensions that promote stiffness, may be substituted in the place of “rigid” components of containers of the invention, while still retaining other advantages over existing containers. 
         [0058]    While the invention has been described with respect to certain embodiments, as will be appreciated by those skilled in the art, it is to be understood that the invention is capable of numerous changes, modifications and rearrangements, and such changes, modifications and rearrangements are intended to be covered by the following claims.