Patent Publication Number: US-2005127074-A1

Title: Collapsible container

Description:
This is a continuation-in-part of application Ser. No. 10/735,724, David Kusuma, filed Dec. 16, 2003. 
    
    
     BACKGROUND OF THE INVENTION  
      The present invention generally relates to molded plastic containers of the type commonly used for a variety of purposes including storage of both food items and non-food items, such containers preferably being adapted to receive an appropriate seal or lid. More specifically, the invention is concerned with containers of this type which, rather than being of a rigid construction as with a conventional bowl, are collapsible or foldable to a compact position when empty to facilitate convenient storage.  
      Such containers, in the form of cups, bowls, and the like, are generally known in the art and take many forms. These include collapsible cups or glasses wherein the glass is formed of telescopically stacked annular wall elements which slide relative to each other between a fully extended position and a collapsed position. As the wall elements are not integrally formed and slide freely relative to each other, there is a substantial possibility of leakage, and use other than as a temporary drinking vessel is not practical. Another form of collapsible container more pertinent to the present invention is illustrated in U.S. Pat. No. 5,439,128, issued to Fishman on Aug. 8, 1995. In the Fishman container, the wall elements are integrally molded and consist of a series of both vertical and angled elements alternately stacked to define the container wall. The elements, at the angular joint therebetween, are integrally joined by thin film hinges about which the wall elements fold. The actual downward folding and collapsing of the Fishman elements requires that the elements flex in order to accommodate the folding motion. This necessity for an actual flexing of the elements themselves, in addition to the folding at the film hinges, appears to be so significant as to, at least in some instances as illustrated in FIG. 3 of Fishman, require significant central relief grooves in each of the inclined wall elements which would appear to cause an inherent weakening of these wall elements. It will also be noted that, in the Fishman container when collapsed, the alternate vertical wall elements of the open container retain their vertical orientation perpendicular to the base wall. As such the Fishman container is clearly not susceptible to injection molding in the collapsed position as would be commercially advantageous due to great economies in mold production and molding procedures.  
     SUMMARY OF THE INVENTION  
      A principal object of the present invention is to provide a collapsible container which presents or forms a substantially rigid receptacle in its open or expanded position and which, with an appropriate lid or seal snap-fit thereto, provides a practical watertight storage container for, as an example, an appropriate foodstuff or the like. The container is very convenient and provides a particularly desirable portable solution for food “on-the-go”, such as at picnics, lunches for those who take their own lunch to work, and other instances wherein temporary storage is desired. The collapsible nature of the container, collapsing to a substantially completely compacted configuration of minimal height, particularly with a seal mounted thereon to confine any residue in the now empty container, allows the used container to be conveniently stored or packed away in a “brown bag”, knapsack, picnic hamper, or the like, for subsequent cleaning and reuse.  
      In furtherance of the principal object of the invention, it is also an object of the invention to provide a method of molding the container in its collapsed position as a means of achieving maximum economies in mold apparatus and procedures, and in providing a molded product which is compact yet fully expandable to a relatively rigid self-sustaining position.  
      A significant aspect of the container of the invention is its capability to fold open in increments, one section at a time, to vary the capacity thereof and at the same time maintain itself in any incrementally folded position.  
      Other desired features of the invention include providing a container which can be washed in a dishwasher in its folded position and stacked therein in the same manner as conventional dishes, a container which stays open when in use and stays closed in storage, and a container which maximizes usable space for packing in a shipping carton as well as storage in the home.  
      In order to achieve the improved and highly practical container of the invention, the peripheral wall of the container, extending between a substantially rigid base and a substantially rigid top ring adapted to receive a snap-fit seal, includes a series of generally rigid annular or peripherally continuous wall sections joined to adjacent sections at fixed annular apex forming joints which are alternately inwardly and outwardly directed relative to the interior of the container. These sections have annular portions therebetween that are relatively flexible. The wall sections, in the expanded or open position of the container, are themselves alternatively angled inward and outward relative to the interior of the container and relative to the vertical, with the wall sections, sequentially upward from the base to the top ring, each being generally diametrically or peripherally progressively greater than the base. The configuration thus formed for the expanded container will be that of an inverted truncated cone with the wall sections basically outwardly stepped upward-from the base. This in turn allows for a direct downward collapsing of the wall sections into concentric surrounding relation to the base with the top ring surrounding the collapsed folded wall sections.  
      The actual folding of the wall sections relative to each other occurs within a flexure portion between the sections where each of the wall sections joins the wall section or sections immediately adjacent thereto and is of a thickness less than that of the thickness of the sections to each side thereof. The thicker sections are both more rigid than the flexure portions and of substantially more limited flexibility. The thinner portions, in the expanded position of the container, form arcuate continuations of the thicker wall sections, forming an arc of greater than 90 degrees and, until physically moved over center during a collapsing of the container, provides a substantial degree of rigidity to the wall sections for the full height of the container wall. Upon the application of a positive physical force collapsing the top ring and base toward each other, the flexible portions between the wall sections will flex laterally in the direction of the fold in the manner of a flexible hinge with this flexure providing for both the actual folding and at the same time, minimizing any tendency for the wall sections to want to laterally flex or move as the wall sections collapse about each other. Each of the flexure zones formed by the thinner wall sections is bordered along each edge thereof by adjacent thicker wall sections. Once the arc of the flexure zone is reduced to less than 90 degrees, moving over center, the inherent resistance to the movement of the flexure zone is overcome and the collapsed zone assumes a dome-like configuration of less than 90 degrees. In moving from the closed to the open state, or vice-versa, each flexure zone is twisted and slightly distorted until it overcomes its stable position and flips to the other position.  
      A collapsed molded container in accordance with the invention is such that opposed rigid wall portions define a generally triangular interstitial space formed by two walls diverging from the vertical in a range of from about 8° to about 40°. However, for reasons that shall become apparent hereinbelow, a preferred range is from about 10° to about 16°.  
      Expansion of the container from its collapsed position will involve a downward push or pull on the base as the top ring is moved vertically upward therefrom. As the flexure portions unfold and move to arcs of greater than 90 degrees, the wall will tend to rigidify and in effect lock the container in the open position.  
      Further features, objects and advantages of the invention will be noted as the construction and details of the invention are more fully hereinafter set forth. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a top perspective view of the container of the invention in its open or expanded position;  
       FIG. 2  is a top perspective view of the container fully collapsed;  
       FIG. 3  is a transverse cross-sectional view of the expanded container;  
       FIG. 4  is a transverse cross-sectional view of the collapsed container;  
       FIG. 5  is an enlarged detailed view of the area designated A in  FIG. 3 ;  
       FIG. 6  is an enlarged detailed view of the area designated B in  FIG. 4 ;  
       FIG. 5A  is a view similar to  FIG. 5  illustrating a modified construction;  
       FIG. 6A  is a view similar to  FIG. 6  illustrating the modified construction;  
       FIGS. 7, 8  and  9  sequentially illustrate one manner of opening, or closing the wall sections utilizing a twisting or sequential ratchet action;  
       FIG. 10  is a cross-sectional view similar to  FIG. 4  with the seal snap-fitted to the collapsed container;  
       FIG. 11  is a cross-sectional detail of a modified pressure bump in the base provided with a pull bar; and  
       FIGS. 12-22  illustrate a further embodiment and sequentially correspond to  FIGS. 1-11 .  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      In the drawings, the features of the embodiment of  FIGS. 1-11  are referred to by two digit numbers. Similar features in the embodiment of  FIGS. 12-22  are referred to by the same numbers with the number  1  as a prefix.  
      Referring now more specifically to the drawings, the collapsible container  10  comprises a base  12 , a top ring  14  and a folding wall  16  extending therebetween. The base  12  is a substantially rigid member including a bottom  18  with a peripheral upstanding base wall  20 . The base, which may be flat, preferably includes a central slightly upwardly extending pressure area or bump  24  of any appropriate configuration, such as a dome, to assist in expanding the container as shall be described subsequently. The base will also preferably have a series of small foot defining knobs  26  or a continuous foot rib, not shown, depending from the base bottom  18 .  
      The top ring  14  includes a continuous or annular ring wall  28  with a peripheral horizontally outwardly directed flange  30  at approximately mid-height on the ring wall  28 . The top ring  14 , similarly to the base  12 , is substantially rigid and is of a greater diameter or other non-circular cross-sectional area than the base  12  to encircle the base in the collapsed position of the container, as in  FIG. 4 , sufficiently outward thereof to accommodate the folded container wall therebetween. The top ring flange  30  provides additional lateral stiffness to the top ring, and a convenient means for handling the bowl, especially when filled. In addition, the ring flange  30 , when the collapsed bowl is to be opened, allows a user to easily engage fingers about and under this flange  30  while pressing downward with the thumbs on the base domed pressure area  24  to forcibly vertically expand the base and top ring relative to each other. As an alternative to pressure on area  24 , particularly with a large bowl, pressure can be applied sequentially about the base bottom  18  immediately adjacent the base wall  20  peripherally thereabout. As desired, and as will be best noted in  FIGS. 1 and 2 , the ring flange  30  can be slightly outwardly extended or enlarged at diametrically opposed portions to define gripping handles  32 .  
      The molding of the base and top ring as separate entities from the wall is a preferred method of molding enabling the provision of substantially greater rigidity to these components relative to the wall sections, wherein the actual extending and collapsing action occurs, by utilization of polymers of differing degrees of rigidity, and/or flexibility.  
      The container side wall  16  is formed of a series of annular or peripherally continuous wall elements or sections  34 , the lowermost section encircling and being intimately bonded, such as autogenously during a multi-component molding procedure, to the wall  20  of base  12  and seated on a support shoulder  21  slightly above the base bottom.  
      In the embodiment of  FIG. 5A , the lowermost or bottom section, being of a height slightly less than the remaining sections thereabove, is integrally joined to a thin upwardly projecting base portion  22  which, as the container wall folds, will define a flexure zone between this lowermost wall section and the base.  
      The wall sections  34 , upward from engagement of the lowermost section with the base, are alternately inclined outwardly and inwardly relative to the interior of the container and to the vertical with each section joined to the section immediately thereabove at alternating outwardly and inwardly directed apexes forming, respectively, angle joints as generally designated at  36  and  38 .  
      Noting  FIG. 5 , the uppermost or top section  34  is joined by a flexure portion to an upwardly directed collar  37  received and intimately fixed within the lower portion of the ring wall  28 , for example in the manner suggested with regard to the lowermost section. In the embodiment of  FIGS. 5A and 6A , the uppermost section  34  is integral or otherwise intimately peripherally joined to the lower edge portion of the top ring  14 .  
      Each of the alternately inclined wall sections, noting the open container, is of a predetermined thickness and of limited flexibility relative to flexure zones or portions  40  joining adjacent sections  34 . The flexure portions  40  are relatively thinner than the sections  34  and substantially equal in thickness to the extending portion  22  of the base in  FIG. 5A . The flexure zones or portions  40  generally define the angled joint,  36  or  38 , between each section and the section immediately adjacent thereto. As noted, the height of these reduced thickness portions  40  is substantially less than the height of the sections  34 . These flexure zone portions  40 , in the expanded or open position of the container, again noting  FIG. 5 , form, with regard to the outwardly inclined wall sections  34 , continuations of the inner face of the corresponding portion  34  therebelow, and, with regard to the inwardly inclined wall sections, are continuations of the outer face of the corresponding wall section. So formed, the thicker wall sections to each side of these flexure zone portions  40 , and the angle thereof, inherently defining the direction of the folding action, note in particular the folding sequence suggested in  FIG. 8 . It will also be appreciated that, prior to folding, the flexure zones  40  and the positioning of these zones  40  between adjacent sections, provides a degree of over center stability to prevent inadvertent collapse of the wall  16 . This stability can only be overcome by a applying sufficient positive vertical pressure, forcing the top ring and base vertically toward each other to effect an over center movement of the flexure zones  40  and a “snap action” folding action of the zones to the collapsed position. Upon initiating the folding action, each involved flexure zone  40  distorts slightly until it moves to what might be considered an over center position, at which point it flips to the folded position. In this manner, any tendency for the container to self close or collapse accidentally, particularly with goods within the container, is minimized.  
      As will be noted in the drawings, the adjacent sections  34 , in the collapsed position of the container, form oppositely facing V-shaped or triangular openings. The center line of each V-shaped opening is generally perpendicular to the horizontal plane of the collapsed container. This structure is significant in allowing the injection mold to separate to eject the molded piece.  
      The angle of divergence between adjacent collapsed sections  34  has an overall possible range of 8° to 40°, with the preferred range being 10° to 16°. An angle of 10° is considered optimum in achieving a desired balance between rigidity of the container in the open position and the force necessary to collapse or expand the container. This angle is also considered, as a practical matter, to be the smallest angle that will allow consistent ejection of the molded piece from the mold. As will be appreciated, as the decreases.  
      With particular attention to  FIGS. 7-9 , it will be seen that, if desired, both the opening and collapsing of the container can be facilitated by applying pressure sequentially about the container or by rotating the container as pressure is applied to provide a stepping or ratching effect on the wall sections  34  rather than by snap positioning each flexure zone in its entirety at one time.  
       FIG. 9  is of particular interest in showing the container partially folded or unfolded for use when a reduced capacity is desired or required. In such a position, the container is fully functional to receive and store foodstuffs and the like, and the seal  42 , as in the open container of  FIG. 3 , is also fully functional in that the top ring is dimensionally stable in every position of the container.  
      Noting in particular  FIG. 3 , it will be seen that the general outward stepping of the sections upward from the base to the top ring forms, in the open container, a generally inverted truncated conical configuration.  
      Again noting  FIGS. 7-9 , as the container is vertically collapsed, the flexure zones  40  fold between adjacent sections to assume a generally domed configuration. Thus the adjacent wall sections are folded to bring the thicker major height of the sections into concentric generally parallel relation to each other, with the angle between adjacent sections preferably being approximately 10° to 16°, with the sections laterally aligned and surrounding said base between the base wall  20  and the top ring wall  28 . This will best be seen in the cross-sectional detail of  FIG. 6 .  
      Noting  FIGS. 3, 9  and  10 , it will be seen that the seal  42  is capable of being snap-fitted to the top ring  14  in an appropriate manner in any position assumed by the container. To facilitate this engagement, the upper portion of the top ring wall  28 , above the circumferential flange  30 , may be slightly outwardly inclined for reception within a peripheral downwardly directed groove on the seal. It is to be appreciated that inasmuch as the folded wall sections are, in any position of the container, positioned concentrically inward of the substantially rigid top ring  14 , the seal  42  functions as an appropriate closure for the open container, the partially expanded container, and the collapsed container wherein a compacted storage position is achieved.  
      As previously noted, when the container is to be opened prior to use, one need merely engage fingers about the peripheral flange  30  of the top ring and, with one or both thumbs, exert a downward pressure on the bottom push bump  24  projecting upwardly from the center of the base bottom  18 . Alternately, pressure can be exerted on the bottom itself sequentially about the periphery thereof. Further, rather than relying on direct pressure on the bump  24  or bottom  18 , and noting  FIG. 11 , a cross bar  44  can be provided diagonally across the concave recess or depression formed by the bump in the lower face of the bottom  18 . This cross bar  44  can be physically gripped by the user&#39;s fingers for a direct downward pull on the container base, moving the base downward relative to the top ring and expanding the wall sections.  
      Again referring to  FIG. 6 , it will be noted that the lowermost folding wall section  34  will act as a limit to the downward collapsing of the remaining wall sections and top ring relative to the base wall, retaining the sections and top ring slightly above a support plane defined by the base bottom and support feet thereon whereby support of the container, both expanded and collapsed, is on the base and base feet rather than on the much thinner flexure zones.  
      Referring now more specifically to the embodiment illustrated in  FIGS. 12-22 , the basic components of this embodiment substantially duplicate those of the previously described embodiment, and as such, have been designated by the same reference numbers with the number  1  as a prefix. Thus, the container  110  is comprised of a base  112 , a top ring  114 , and a folding wall  116  of alternating rigid wall sections  134  and flexure zones or portions  140 .  
      The container  110 , as with the first embodiment, both expands and collapses in the previously described manner and, in the collapsed position, is so configured as to allow for a practical and preferred molding of the container in this position. Pursuant thereto, the wall sections  134 , in the collapsed position, define oppositely facing V-shaped openings where the angle between the sections, while having a possible range of 8° to 40°, will preferably be in the range of 10° to 16° with an optimum angle of 10°. Each V-shaped opening has the centerline thereof, extending from the apex defined by the converging sections  34 , perpendicular to the horizontal plane of the collapsed container. In the expanded or open position of the container, the wall sections  134  angle both relative to each other, at greater than 90°, and to the vertical as defined by a perpendicular to the base.  
      In order to enhance the folding and unfolding action of the wall sections  134 , each wall section  134 , along the edges thereof, is beveled, as at  135 , to provide a gradual transition area between the wall section  134  and the adjacent flexure portion  140 . This differs from the rather abrupt transition area of the first embodiment, note in particular  FIGS. 5 and 6 .  
      As with the first embodiment, the flexure zone portions  140 , in the open position of the container, form, with regard to the outwardly inclined wall sections  134  of  FIG. 16 , continuations of the inner face of the corresponding section  134  therebelow. Similarly, the flexure zone portions  140 , with regard to the inwardly inclined wall sections  134 , are continuations of the outer face of the corresponding wall section  134 . This relationship, as previously described, will inherently tend to define the direction of the folding action, note in particular the folding sequence suggested in  FIG. 19 , as well as the previously described  FIG. 8 .  
      With particular reference to  FIGS. 16 and 17 , it will be seen that the bottom wall section  134  is of a greater height than the wall sections thereabove, and extends for the full height of the peripheral upstanding base wall  120 . The lower extremity of this lowermost wall section  134  is turned under the bottom  118  of the base  112  and engaged within a receiving recess  119 , thus in effect defining a portion of the support plane of the container. As will be appreciated, the enhanced area of overlap between the lower portion of the container wall and the base enhances the joinder therebetween.  
      The engagement of the container wall to the top ring is effected by a laterally directed collar  137  joined to the uppermost wall section  134  by the uppermost flexure portion  140 . The collar  137  includes an upwardly directed locking bead  139  on the outer edge thereof with both the collar  137  and bead  139  being received within a corresponding locking recess found in the base of annular ring wall  128 . The top ring  114 , as with the previously described ring  14 , includes an integral annular outwardly projecting ring flange  130 , providing both lateral stiffness to the top ring and a convenient means for both manipulating and handling the bowl. As a means for facilitating a gripping of the flange, it is proposed that an integral depending gripping bead  131  be provided peripherally about the outer edge portion of the flange  130 .  
      A final area of variance between the embodiments will be seen in  FIG. 12 , and the various cross-sectional views of the container  110 . As will be appreciated from a comparison of these figures with the figures of the first embodiment, the base  112  includes a substantially enlarged central upwardly extending pressure area or bump  124 . This enhances the area upon which opening pressure, in particular, can be applied, facilitating the manipulation of the container and at the same time having a tendency to further strengthen the otherwise flat bottom  118 . As noted in  FIG. 22 , the bottom push bump  124  can also be provided with a diagonal cross bar  144  for purposes previously noted with regard to cross bar  44 .  
      Also, as described with regard to the first embodiment, an appropriate seal  142 , capable of being snap-fitted to the top ring  114  can be provided. Such a seal, in light of the manner of collapsing and expanding the container with the concentric folded wall sections, will comprise an appropriate closure for the container whether fully open, fully collapsed, or partially expanded.  
      With reference to  FIG. 21  in particular, it will be seen that the downwardly collapsed wall sections  134 , and more particularly the downwardly directed flexure portions  140  are retained slightly above the support plane defined by the base bottom and/or support feet, providing a more stable support and avoiding engagement of the substantially thinner flexure zones with a support surface.  
      The container as described is designed in a configuration that utilizes a “network” of flexure zones. It is not an accordion shape that stretches to open and close like a spring. Instead, the flat storage container functions to open and close based on a principle of “opposing angles”.  
      In known expanding containers, the containers are generally molded in the open or expanded configurations. Open is thus the natural state for those containers, that is those containers would ‘prefer’ to remain open than in any other position. Thus, when one tries to fold or collapse these containers, the containers tend to want to spring back open, that is return to their natural state. This is not the case with the container of the invention wherein the container is preferably molded in a flattened or collapsed position. This is its initial natural state meaning that the container will initially prefer to stay in this closed configuration. There are multiple folds within the network of flexure zones. In the illustrated embodiment three sets of independently activating zones are provided (more can be added to increase capacity if desired). As seen in  FIG. 9 , each of the independently activatable flexure zones has a second ‘natural’ or at rest state when open wherein the fold will prefer to remain open independently of the remaining folds. In the present structure, both the action of collapsing the container and the action of expanding the container require the folds to be individually manipulated. Positive action is required to both fold and unfold the container. This can be referred to as the principle of “opposing angles”. The angle of the fold in the closed position keeps the fold closed; the angle of the fold in the open position keeps the fold open. To move from the closed to the open state or vice-versa, the flexure zone is twisted and distorted slightly until it overcomes the opposing angle and then flips to the other position configuration. This action results because the diameters of the flexure zones cannot change. There is no other intermediate position for the fold. It is either open or closed, or it is being twisted(one side open and the other side closed). It is not possible in this construction for an individual section to be, as an example, half open while maintaining usable capacity. As previously noted, one easy way to manipulate the flexure zones is to ‘ratchet’ the container, one side at a time to a partial or fully open position.  
      The unique structure of the invention allows the container to remain flat when in the closed or collapsed position and remain expanded when in any open or partially open position. Because of the two ‘natural’ states for the flexure zones, the container prefers to remain closed when collapsed flat and prefers to remain open when expanded. With the independent activation of the flexure zones in the network, the container is capable of opening to fixed partial capacities, because the container prefers to remain open in these partial configurations. This is of particular value in maximizing and optimizing storage space as in a refrigerator, and dishwasher space when washing.  
      The collapsible container of the present invention has been described in the preferred embodiments as comprising one of molded plastic, i.e. synthetic polymers, having ‘separate entities’ comprising a base, top ring and folding wall. The ‘separate entities’ in a preferred molding method may, for example, be realized by utilization of molding apparatus that enables multiple stage molding of the base; top ring and folding wall, and wherein selection of polymers of varying degrees of substantial rigidity and/or general rigidity may be utilized. This also enables the varying of the color or light transmissivity of the base, top ring and folding wall.  
      It will be appreciated that as described in connection with the embodiment of  FIGS. 5A and 6A , the container of the present invention may be molded as a unitary structure in essentially a single molding step. In addition, the described preferred difference in relative rigidity, or general, but more flexible, rigidity of the base and ring vis-a-vis the folding wall, may be achieved in a single molding step by selection of appropriate thicknesses of the several portions. The possibility also exists to provide molding apparatus wherein a mold is configured to provide selected areas of the mold interior with polymers of varying degrees of rigidity or flexibility for the base, top ring and wall.  
      It will be appreciated that a mold suitable for injection molding of the wall portion in a collapsed condition will require a plurality of concentric annular interdigitated generally triangular, or V-shaped mold elements, carried by mold halves, corresponding to the number of wall sections folded on each other.  
      The foregoing is considered illustrative of the principles of the invention. As modifications and changes may occur to those skilled in the art, it is not desired to limit the invention to the exact construction and manner of use as shown and described. Rather, all suitable modifications and equivalents may be resorted to as falling within the scope of the invention as claimed.