Abstract:
Collapsible portable containers having a foldable wall section with shape-retaining characteristics are disclosed. In particular, collapsible, wheeled suitcases and trolleys are provided. One or more casters of a collapsible suitcase may be retractable to permit a folding region of a wall section to overlap the depth dimension of the casters when in the collapsed position. 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. The non-folding tier may be of the same material as the flexible tiers but stiffer due to its geometry, or it may be 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 101 046.7, filed Mar. 10, 2014, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to shape-retaining, collapsible, portable containers, including suitcases and trolleys. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is desirable for a luggage item to be able to collapse to relatively compact dimensions for storage or transport when the luggage item is either not in use or being used to hold less than its maximum volume capacity of contents. Collapsible luggage of various kinds exist to accommodate these general needs. However, multiple challenges are inadequately addressed by existing collapsible luggage. 
         [0004]    In particular, existing collapsible luggage, while capable of expanding to the volume of contents held therein, generally collapses to its more compact shape when empty. For example, “duffel bags,” typically composed of a flexible fabric material such as canvas or nylon on most or all sides, limply collapse flat or nearly flat when empty, thus making them awkward to pack compared to their hard-bodied counterparts, as the available height dimension does not become visually apparent until packing has already begun, and moreover, a packer often will have to use one hand to hold the bag open while inserting contents with the other hand. Also, a duffel bag typically provides little or no structural rigidity to protect its contents. 
         [0005]    On the other hand, some existing suitcases feature one or more zippered expansion panels for selectively permitting the interior volume to expand by opening a zipper to allow the panel to stretch or unfold to its maximum width. In a common type of wheeled carry-on suitcase, such zippered expansion panels provide a selectively expandable dimension between a pivotally opening front closure panel and a back section which is typically permanently attached to a relatively stiff or rigid peripheral wall section. However, the expansion panel itself is typically made of a limp fabric that is incapable of passively retaining its expanded state, but rather would collapse under its own weight and/or the weight of one or more portions of the suitcase positioned above the expansion panel when the suitcase is laid out on its back panel for packing/loading. Additionally, such an expansion panel provides little to no resistance to deformation except in tension, and thus little to no protection of suitcase contents against side impacts, for example. 
         [0006]    A need therefore exists for suitcases and other transportable and fully closable 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 intrinsically resistant to compressive deformation over at least a portion of a collapsible wall region. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    According to one aspect of the invention, a collapsible suitcase is provided, comprising a front section; a back section; and a collapsible wall section connecting the front section to the back section, the collapsible wall section including at least three stacked, generally annular tiers. In the context of the present invention, “collapsible” means “collapsible and expandable;” that is, the containers of the invention can be collapsed from a relatively expanded state and expanded from a relatively collapsed state, and these operations can preferably be repeated a large number of times without any substantial change in the response of the container to each successive cycle of collapsing and expanding. Advantageously, the front and back sections may be composed of a relatively hard, rigid material to help protect and maintain the order of the contents of the suitcase. The front and back sections optionally but preferably include a generally flat front and back panel, respectively. The front and back sections may alternatively include contoured front and/or back surfaces as desired. One or both of the front and back sections may also include a peripheral wall portion that surrounds the flat panel and extends toward the opposite panel to form a part of the overall wall structure of the suitcase. The front section and back section are not defined by their particular shape, but rather by cooperating with the collapsible wall structure to enclose a storage volume. In this context, “enclosed” does not necessarily mean totally devoid of perforations or openings, but rather enclosed to a degree that a traveler would normally find sufficient for suitcase purposes. 
         [0008]    At least one of the tiers of the collapsible wall section is relatively stiff, with at least one neighboring flexible tier disposed both in front of and behind (i.e., above and below, when the suitcase is placed on its back side for packing) the stiff tier. Thus, the size of the storage volume can be increased, by expanding or unfolding at least one of the flexible tiers from a relatively collapsed to a relatively expanded position; and decreased, by folding at least one of the flexible tiers from a relatively expanded to a relatively collapsed position. The stiff tier is preferably a rigid tier made of a different, harder material than the flexible tiers. Alternatively, it may be made of the same material and simply be thicker or otherwise geometrically shaped or oriented to have greater resistance to folding or inverting than the flexible tiers. 
         [0009]    Preferably, the flexible tiers, despite being flexible enough to fold under a reasonable amount of manually applied force, are also stiff enough for the suitcase to be self-supporting when lying on its back side in any fully or relatively expanded state. On the other hand, the flexible tiers preferably do not have a tendency to snap back to an expanded/unfolded position once collapsed/folded, but rather exhibit “over-center” stability, being biased toward a folded position once folded past a certain threshold point, and biased toward an unfolded position once unfolded past a certain threshold point. 
         [0010]    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 front and rear ends of the flexible tier. Beyond the ends of the flexible tier, the material tapers back out to an increased thickness, and a wider 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. 
         [0011]    If the stiff tier is a rigid tier made of a different material than the flexible tiers, the rigid tier may, for example, be polypropylene (or “PP”), with the adjacent flexible tiers being a thermoplastic elastomer (or “TPE”) overmolded onto the polypropylene. Alternatively, the rigid tier may, for example, be composed of metal or nylon, and the flexible tier of silicone that is overmolded onto the metal or nylon, the silicone tier being connected to the metal or nylon tiers with or without an adhesive between them to strengthen their connection. Although not illustrated in the figures, other suitable means for joining together rigid and flexible tiers may be employed, including mechanical fasteners. 
         [0012]    Where the front section includes a front panel, the front panel is preferably connected by a pivotal joint extending along a generally straight portion of the perimeter of the suitcase, and a zipper extending at least part of the rest of the way around the suitcase. The zipper and pivotal joint should be relatively situated so that when the zipper is fully opened, the front panel is free to pivot open, and when the zipper is fully closed, the front panel cannot pivot open. Preferably, the suitcase also includes a lock to prevent the zipper from being opened, such as one that retains a pair of zipper pulls in fixed positions next to each other, as in the illustrated embodiment. 
         [0013]    An alternative or second possible location for a zipper is within the stiff or rigid tier of the collapsible wall section. If such a zipper is included, the stiff or rigid tier may include two separate annular stiff or rigid bands connected to each other by a pivotal joint and a zipper, substantially in the manner described above for the front-panel. The suitcase also preferably includes other features typical of a travel suitcase, such as casters and an extendable handle for rolling the suitcase across a floor surface. 
         [0014]    According to another aspect of the invention, collapsible trolleys similar to the collapsible suitcases are provided. The collapsible trolleys differ from the collapsible suitcases primarily in that they include a pivoting lid closure instead of a zippered panel, which may for example snap closed over an upper rim of the trolley container body. This advantageously facilitates uses of the trolley that require frequent opening and closing, compared to the zippered closure typical of the suitcase. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view of a suitcase according to one embodiment of the invention, in an expanded state. 
           [0016]      FIG. 2  is a perspective view of the suitcase depicted in  FIG. 1 , in a collapsed state. 
           [0017]      FIG. 3  is a perspective view of the suitcase depicted in  FIG. 1  with its front panel opened. 
           [0018]      FIG. 4  is a perspective view of a suitcase according to an alternative embodiment, having a middle zipper. 
           [0019]      FIG. 5  is a perspective view of the suitcase of  FIG. 4  in a collapsed state. 
           [0020]      FIG. 6  is a perspective view of the suitcase of  FIG. 4  with its middle zipper opened and its front half flipped open. 
           [0021]      FIG. 7  is a sectional elevation view of the suitcase of  FIG. 1  in an expanded state. 
           [0022]      FIG. 8   a  is a sectional elevation view of the suitcase of  FIG. 1  in a collapsed state. 
           [0023]      FIG. 8   b  is a fragmentary sectional elevation view of the suitcase of  FIG. 1  depicting the collapsible wall section in a partially collapsed state. 
           [0024]      FIG. 8   c  is a fragmentary sectional elevation view of the suitcase of  FIG. 1  depicting the collapsible wall section in another partially collapsed state. 
           [0025]      FIG. 9  is a sectional elevation view of the suitcase of  FIG. 4  in an expanded state. 
           [0026]      FIG. 10   a  is a sectional elevation view of the suitcase of  FIG. 4  in a collapsed state. 
           [0027]      FIG. 10   b  is a fragmentary sectional elevation view of the suitcase of  FIG. 4  depicting the collapsible wall section in a partially collapsed state. 
           [0028]      FIG. 10   c  is a fragmentary sectional elevation view of the suitcase of  FIG. 4  depicting the collapsible wall section in another partially collapsed state. 
           [0029]      FIG. 11  is a cutaway perspective view of a retractable caster mechanism of the suitcase of  FIG. 1  according to an aspect of the invention, depicting retractable casters in an extended position. 
           [0030]      FIG. 12  is a cutaway perspective view of the retractable caster mechanism of  FIG. 11 , depicting retractable casters in a retracted position. 
           [0031]      FIG. 13  is a cutaway perspective view of a retractable caster mechanism of the suitcase of  FIG. 4  according to an aspect of the invention, depicting retractable casters in an extended position. 
           [0032]      FIG. 14  is a cutaway perspective view of the retractable caster mechanism of  FIG. 13 , depicting retractable casters in a retracted position. 
           [0033]      FIG. 15  is a perspective view of a trolley according to an aspect of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0034]    Collapsible containers with improved shape retention and structural integrity provided by the present invention are described herein. In particular, fully closable, collapsible containers especially suitable for use as suitcases and trolleys are described and illustrated with reference to  FIGS. 1-15 . 
         [0035]    Turning to  FIGS. 1-14 , suitcases according to one embodiment of the invention are described and illustrated. Suitcase  10 , depicted in  FIGS. 1-3 ,  7 ,  8   a - 8   c ,  11 , and  12 , includes a hard front section  12 , a hard back section  14 , and a foldable wall section  16  that may be collapsed and expanded to vary the space between front section  12  and back section  14 , and thus the available volume for packing contents into suitcase  10 . Wall section  16 , in turn, includes a stiff tier  18  between two flexible tiers  20  and  22 . 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 suitcase  10 . A fully expanded state of suitcase  10  is illustrated in  FIGS. 1 ,  3 ,  7 , and  11 , showing both flexible tiers  20  and  22  in unfolded positions, while a fully collapsed state of suitcase  10  is illustrated in  FIGS. 2 ,  8   a , and  12 , showing both flexible tiers  20  and  22  in folded positions. Two partially collapsed states of suitcase  10  are illustrated in  FIGS. 8   b  and  8   c , 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 suitcase  10  to its fully expanded, fully collapsed, and two partially expanded states illustrated in the Figures. 
         [0036]    Of course, it will be understood that “stiff,” “rigid,” and “flexible” are relative terms. In the context of the present description of the invention, unless further specified, referring to a tier of a suitcase wall section as “stiff” 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 or inverting its orientation from front to rear, relative to the front and back sections of the suitcase. On the other hand, a tier that is considered “rigid” for purposes of the invention typically will not appreciably yield or deform, let alone fold, in the front-to-back 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 suitcase. Still further, a “rigid” tier preferably will not appreciably deform in any direction during normal use of the suitcase, thus providing protection to the contents against damage or disarray caused, for example, by side impacts or other lateral forces applied to wall section  16 . 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. 
         [0037]    Although each of flexible tiers  20  and  22  are shown 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 (typically thinner or weakened regions made of the same material), so that each pleat can be independently folded and unfolded (not shown), being stable in either state. Also, a suitcase according to the invention need not have the generally rectangular peripheral shape of suitcase  10  as shown in the Figures, but may have any suitable shape, such as round, oval, or other shape as desired. In addition, the direction of expansion need not be normal to the front and back sections of a suitcase, but could be made to be at an oblique angle to the front and back sections as desired. For example, providing a slanted wall section, instead of the generally symmetrical wall section shown in the Figures, could permit the suitcase to expand in such an oblique direction. Furthermore, the path of expansion need not be straight, but could be curved as desired. For example, successive accordion pleats may be stable in relatively “bent” orientations, in which part of the peripheral or circumferential length of a pleat is folded and the remainder of the length is unfolded. 
         [0038]    Front section  12  is shown in the Figures as comprising a front panel  23  connected to a rigid front wall section  24  by a hinge  26  and a front section zipper  28 , thus permitting access to the interior of suitcase  10  by opening zipper  28  and pivoting front section  12  into the open position illustrated in  FIG. 3 . Alternatively, front section  12  may be secured by any suitable closure mechanism, including but not limited to clasps, latches, hooks, or straps (not shown). Optionally, a suitable locking mechanism, such as lock  30 , which retains zipper pulls  32  in fixed positions when engaged, may be provided to secure the closure of suitcase  10 . 
         [0039]    To facilitate transport, suitcase  10  includes a suitable grasping means such as a retractable handle  34  connected to back section  14 , as shown, for example, in  FIG. 1 , and casters  36 ,  38  for rolling suitcase  10  along a ground or floor surface. In the example of suitcase  10 , casters  36  are fixedly attached to rigid front wall section  24 . Advantageously, casters  38  are retractably mounted to back section  14  to permit casters  38  to be moved out of the way of the collapsing movement of wall section  16  for compact stowing of suitcase  10 , as best illustrated in the cross-sectional elevation view of suitcase  10  depicted in  FIG. 8   a . A retractable mounting assembly  40  allowing casters  38  to be alternately locked in their extended and retracted positions is illustrated in  FIGS. 7 and 8   a - 8   c . A carrying handle  42  is also included in suitcase  10  for lifting and carrying suitcase  10  when rolling transport of suitcase  10  is not possible or not preferred. 
         [0040]    Turning to  FIGS. 4-6 ,  9 ,  10 ,  13 , and  14 , an alternative embodiment of the invention is described and illustrated as a suitcase  10 ′ which is substantially similar to suitcase  10 , but in which a middle stiff or rigid tier  18 ′ comprises two halves closeable by a middle zipper  44  and pivotally joined at a middle hinge  46  (which may for example simply be a piece of flexible material as illustrated), permitting suitcase  10 ′ to be pivotally opened to the position depicted in  FIG. 6 . Suitcase  10 ′ is shown as including both middle zipper  44  and a front zipper  28 ′, but a front zipper could alternatively be omitted in a suitcase including a middle zipper. Although not shown in the Figures, both middle zipper  44  and front zipper  28 ′ may be lockable by a suitable locking mechanism, which may for example be analogous to lock  30  of suitcase  10 . Features of suitcase  10 ′ that are similar to those of suitcase  10 , so as to require no separate description, include a front panel  23 ′, a back section  14 ′, a foldable wall section  16 ′, flexible tiers  20 ′ and  22 ′, a hinge  26 ′ connecting front panel  23 ′ to suitcase  10 ′, the aforementioned front zipper  28 ′, a retractable handle  34 ′, casters  36 ′ and  38 ′, a retractable caster mounting assembly  40 ′, and a carrying handle  42 ′. As illustrated in the drawings, suitcase  10 ′ does not include an analogous feature to rigid front wall section  24  of suitcase  10 , and casters  36 ′ are instead attached directly to front panel  23 ′, while front zipper  28 ′ directly connects front panel  23 ′ to flexible tier  20 ′. However, the omission of a rigid front wall section, to which a front panel is connected by a zipper, and to which casters are attached, is not strictly required by the incorporation of middle zipper  44 . Rather, a suitcase including all of the features of suitcase  10 , and differing from suitcase  10  essentially only by the addition of a middle zipper and a middle hinge within middle tier  18 , would also be within the scope of the invention. 
         [0041]    Suitcases  10  and  10 ′ may be constructed of any suitable materials that impart relative rigidity to front section  12 ,  12 ′ and back section  14 ,  14 ′; relative stiffness or rigidity to middle tier  18 ,  18 ′, and relative flexibility to flexible tiers  20 ,  20 ′ and  22 ,  22 ′, while permitting the various components of suitcase  10 ,  10 ′ to be durably attached to their neighboring components. For example, front section  12 ,  12 ′, back section  14 ,  14 ′, and/or a rigid version of middle tier  18 ,  18 ′ may be composed of polypropylene, flexible tiers  20 ,  20 ′ and  22 ,  22 ′ being a thermoplastic elastomer overmolded onto the polypropylene. Alternatively, front section  12 ,  12 ′, back section  14 ,  14 ′, and/or a rigid version of middle tier  18 ,  18 ′ may be composed of metal or nylon, flexible tiers  20 ,  20 ′ and  22 ,  22 ′ being a silicone material overmolded onto the metal or nylon with an adhesive glue between the two materials to strengthen their connection. Alternatively, a stiff but not rigid middle tier  18 ,  18 ′ may be composed of the same material as flexible tiers  20 ,  20 ′ and  22 ,  22 ′, but with a greater thickness and/or a more vertical relaxed orientation than the flexible tiers, to impart to middle tier  18 ,  18 ′ a greater resistance to deformation in general, and to folding in particular. 
         [0042]    With reference to  FIG. 15 , a trolley  48  embodying another aspect of the invention is depicted. Similarly to suitcases  10  and  10 ′, trolley  48  includes a hard top section  52 , a hard bottom section  53   a  middle stiff or rigid tier  54  flexible tiers  56  and  58  interposed between the middle stiff or rigid tier  54  and the respective top and bottom sections, as well as casters  60  and a retractable handle  62  and/or pivoting handles  64  to facilitate its rolling transport. Trolley  48  is depicted as including flip-top lid  66 , which may have snap-fit rims or close with clasps, instead of a zippered front panel as in suitcase  10 . Lid  66  may flip open as a unit or in sections as desired. Lid  66  makes frequent access faster and more convenient than a zippered panel, by requiring only a single lifting motion to open. Thus, trolley  48  may be particularly suitable for uses as portable containers that demand frequent opening and closing, such as picnic containers/coolers, gardening or yard waste bins, water containers/coolers, garbage cans, laundry bins, a container for storing or hauling tools and/or appliances, or a container for miscellaneous items that may conveniently be transported in the trunk or rear of a car, such as groceries or other store-bought items. 
         [0043]    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.