Patent Document

FIELD OF THE INVENTION 
       [0001]    The present invention relates to container holders and methods of holding containers to permit removal of selected containers. More particularly, the invention relates to an adjustable container holder for alternately holding nested stacks of containers of various sizes. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the high-volume restaurant industry, containing food items is a significant part of providing food to customers. Typically, food is served in disposable containers for customers to carry away from the restaurant. To provide the most efficient service, it is essential for kitchen employees to have consistent, quick and easy access to these food containers. Thus, container holders adapted to be retained in a fixed position and to hold a plurality of food containers are frequently employed. Currently, multiple container holders are typically used in the same setting to accommodate food containers having various standard sizes corresponding to various types of food items. This results in wasted time and/or space for food preparation. For example, at breakfast time, when biscuits and croissants are more popular than hamburgers, hamburger container holders may take up space that would be better used for biscuit or croissant holders. Alternatively, an employee may have to take the time to move the hamburger holders and replace them with more biscuit or croissant holders. Either way, existing container holders place a burden on efficient customer service. 
         [0003]    A need therefore exists for a container holder adapted to hold a plurality of containers for consistent, quick and easy removal of selected containers, without taking up excessive space or requiring excessive set-up time. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    In accordance with one aspect of the present invention, an adjustable container holder is provided. The container holder includes a support and two generally parallel spaced apart prongs mounted to the support for movement relative to each other. At least one of the prongs is movable relative to the support to adjust the spacing between the prongs while maintaining the generally opposed orientation of the prongs. The other prong may be movable or fixed relative to the support as desired. A spring operatively connected to at least one of the prongs is configured to provide a force to urge that prong towards the other prong and to cause the prongs to exert a clamping force when a container is located between the prongs to hold the container between the prongs. The prongs may additionally each include a detent at their ends to prevent removal of boxes not intentionally selected for removal. If desired, the prongs may extend generally horizontally from the support so that the container holder may conveniently hang on a wall or other fixed vertical structure. The spacing between the prongs may be generally horizontal. 
         [0005]    Preferably, the clamping force is large enough to retain a plurality of nested corrugated paperboard clamshell single-serving sandwich containers, and small enough to avoid damaging or undesirably deforming the containers when the spacing between the prongs is from about 2.5 inches to about 6 inches, a range that encompasses the widths of a substantial variety of typical fast-food clamshell sandwich boxes. The present inventors have found that clamping forces between about 0.1 pound and about 1.5 pounds is preferable. 
         [0006]    In one embodiment, the spring is a substantially constant force spring. For example, the spring may be a flat spiral spring. In another embodiment, the spring is a variable-force spring that is preloaded to nonetheless provide a substantially constant force over the range of movement of the prongs relative to each other. In both of the foregoing embodiments, the clamping force is substantially constant over a full range of spacing between the prongs permitted by the movement relative to the support of at least the first prong. 
         [0007]    In still another embodiment, the spring is a variable-force spring providing a variable clamping force, but the clamping force remains within the useful range wherein the clamping force is adequate to grip but not damage a container. 
         [0008]    When the container holder is combined with a plurality of nested containers held between its prongs, a container dispenser is formed, from which a desired number of containers may be selectively removed for use. 
         [0009]    In another aspect of the present invention, a method of holding a container for subsequent removal is provided. According to the method, a container holder as generally described above is provided. The prongs of the holder are moved apart from each other to a sufficient spacing to permit a container to be located between the prongs, and a container is located between the prongs. For example, the container may be a typical fast-food clamshell sandwich box having a hinge. The prongs are released to permit the spring force to urge the prongs closer to each other and to clamp the container between the prongs. Releasing the prongs preferably results in a clamping force from about 0.1 to about 1.5 pounds being applied to the container. If the container is a clamshell box, it may be clamped at the ends of its hinge. 
         [0010]    In one embodiment of the method, a stack of nested containers is located between the prongs. A selected container may then be removed from the holder by gripping the selected container and sliding it toward the free ends of the prongs to separate the selected container from an adjacent nested container in the stack. The clamping force of the prongs, and the detents, if they are included, help to prevent the adjacent nested container from clinging to the selected container. The selected container is then removed by pulling it past the free ends of the prongs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a rear-left perspective view of a container holder according to the invention holding typical fast-food clamshell sandwich boxes. 
           [0012]      FIG. 2  is a front-right perspective view of a container holder according to the invention holding typical fast-food clamshell sandwich boxes. 
           [0013]      FIG. 3  is a frontal perspective view of a container holder according to the invention holding typical fast-food clamshell sandwich boxes. 
           [0014]      FIG. 4  is a rear-left perspective view of a container holder according to the invention illustrating the fully retracted configuration thereof. 
           [0015]      FIG. 5  is a rear-left perspective view of a container holder according to the invention illustrating a partially extended configuration thereof. 
           [0016]      FIG. 6  is a front-right perspective view of a container holder according to the invention illustrating a partially extended configuration thereof. 
           [0017]      FIG. 7  is a front-right perspective view of a container holder according to the invention illustrating a fully retracted configuration thereof. 
           [0018]      FIG. 8  is a fragmentary rear-right perspective view of a movable prong of a container holder according to the invention, illustrating the manner of attachment of the movable prong to a flat spiral spring. 
           [0019]      FIG. 9  is a rear-view schematic illustration of an alternative spring mechanism for a container holder according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Container holders adapted to hold a plurality of different-sized containers are described in this section. With reference to the Figures generally, container holders are described which are adapted to provide a clamping force that is sufficient to grip typical fast-food sandwich clamshell boxes having a range of different sizes but insufficient to damage or undesirably deform the boxes. According to one embodiment illustrated in  FIGS. 1-8 , a container holder  10  incorporating a substantially constant-force flat spiral spring  12  is described. According to an alternative embodiment, an alternative spring mechanism incorporating a variable-force spring  12 ′ is also described in this section, with reference to  FIG. 9 . 
         [0021]    Referring generally to  FIGS. 1-8 , the structure of container holder  10  incorporating a substantially constant-force flat spiral spring  12  is described in the following paragraphs. 
         [0022]    Container holder  10  includes a pair of generally opposed prongs  14  and  16 , where prong  14  is shown as a right prong that is slidingly connected to a back plate  18 , and prong  16  is shown as a left prong that is fixedly attached to back plate  18 . Turning to  FIG. 4 , a U-shaped base portion  20  of right prong  14  is slidingly received between lower slide tabs  22   a, b  and upper slide tabs  24   a, b  of back plate  18 . A protruding portion of a stop member  25 , seen in  FIGS. 1 ,  4  and  5 , substantially prevents base portion  20  from sliding further in the direction indicated by arrows E when base portion  20  impinges stop member  25 , thus preventing base portion  20  from sliding off of back plate  18 . Stop member  25  is illustrated as a rivet having a base portion at the front side of a rib  27  of back plate  18 , as seen in  FIGS. 6 and 7 , and extending backwardly therethrough, as seen in  FIGS. 1 ,  4  and  5 . Alternatively, stop member  25  could be welded to or formed in rib  27 , or otherwise attached to any suitable part of back plate  18  so as to substantially prevent base portion  20  from sliding off of back plate  18 .  FIG. 8  is a fragmentary illustration of the integral attachment of right prong  14  to sliding base  20 , whereby a thinner bent rod  26  is welded to a thicker bent rod  28 . Bent rod  26  includes a longitudinal portion  30 , a shoulder detent  32   a , and a vertical spring post  34 . Bent rod  28  includes a longitudinal portion  36  and a transverse U-shaped base portion  20  which, as shown fully in  FIG. 4 , fits slidingly between slide tabs  22   a, b  and  24   a, b.    
         [0023]    The structure of left prong  16  is shown in  FIG. 6 . Similarly to right prong  14 , left prong  16  includes a thinner bent rod  40  welded to a thicker bent rod  42 . Bent rod  40  includes a longitudinal portion  44  and a shoulder detent  32   b . Bent rod  42  includes a longitudinal portion  48  and a transverse L-shaped base portion  50  which is welded to beads  52 ,  54  and  56  of back plate  18 . In this manner, left prong  16  is fixedly attached to back plate  18 . 
         [0024]    Back plate  18  itself additionally includes a hanging lip portion  58 , adapted for hanging back plate  18  on a suitable fixed vertical structure (not shown), and a stepped foot portion  60 , adapted for propping back plate  18  away from the fixed vertical structure, so as to avoid impingement of the structure by flat spiral spring  12  and/or by right prong  14 . 
         [0025]    With reference to  FIGS. 4 and 6 , flat spiral spring  12  includes a spiral-coiled portion  62  which winds around spring post  34  of right prong  14 , and an uncoiled, generally flat portion  64  which connects by a spring lip  66  to spring receiving slot  68  in back plate  18 . 
         [0026]    The function of container holder  10  will now be described, with reference to  FIGS. 1-7 . In  FIGS. 1-3 , container holder  10  is shown holding a stack of nested quick service restaurant clamshell sandwich boxes B. The generally elongate shape of prongs  14  and  16  makes them particularly well suited to be received in notches N typically found at the ends of hinges H of clamshell boxes B. Additionally, the disposition of thinner bent rods  26  and  40  inward and downward relative to thicker bent rods  28  and  42  matches the taper of the upper side of notches N, as best shown in  FIG. 3 , thus improving the frictional contact between prongs  14  and  16  and notches N by comparison to single-rod prongs. This frictional contact is beneficial, as it restrains or prevents accidental sliding of boxes B toward the ends of prongs  14  and  16 , as well as helping to retain the remainder of boxes B in place when a selected box B or plurality of boxes B are intentionally removed from container holder  10 . Likewise, the inward curvature of shoulder detents  32   a, b  is adapted so that they partially obstruct but do not wholly prevent the removal of boxes B, so that intentionally applying a sufficient force will remove boxes B that one desires to remove, but not boxes B that one desires to leave, including lower boxes B that “cling” to upper boxes B in which they are nested, for example. 
         [0027]    Boxes B are held between prongs  14  and  16  by a clamping force represented by arrows F in  FIGS. 1-3 . In the embodiment illustrated in  FIGS. 1-8 , clamping force F is provided by substantially constant-force flat spiral spring  12 . In particular, spring  12  produces a force tending to wind up coiled portion  62  toward generally flat portion  64 , thereby pulling spring post  34  inwardly towards spring receiving slot  68 . 
         [0028]    In the fully retracted configuration of container holder  10  illustrated in  FIGS. 4 and 7 , the base of right prong  14  is braced against the right edge of back plate  18 , as best seen in  FIG. 7 . In this configuration, there is no net clamping force between prongs  14  and  16 , and prong  14  is only free to move away from prong  16  to extend the width of the gap between prongs  14  and  16  in the direction indicated by arrows E. The fully retracted, minimum width of the gap between prongs  14  and  16  is denoted in  FIGS. 4 and 7  as G R . 
         [0029]    On the other hand, in the extended configuration of container holder  10  illustrated in  FIGS. 5 and 6 , right prong  14  is pulled away from the edge of back plate  18  and is free to retract in the direction indicated by arrows R as well as to extend further from prong  16  in the direction indicated by arrows E. In the extended configuration, the force of spring  12  results in a clamping force F tending to move prongs  14  and  16  back together towards the retracted configuration. Because spring  12  is a substantially constant-force spring, clamping force F remains substantially the same over a range of extended gap widths G E , one example of which is shown in  FIG. 5 . Thus, by appropriately selecting and configuring the elements of container holder  10 , and particularly the spring force provided by spring  12 , prongs  14  and  16  can be made to grip different boxes having a range of sizes firmly enough to retain the boxes, but not so firmly as to damage or undesirably deform the boxes. It should be noted that the maximum permitted gap width G E  will be determined by the configuration of stop member  25 , as by preventing further extension movement of base member  20 , stop member  25  also prevents further extension movement of prong  14  away from prong  16  when base member  20  impinges stop member  25 . Thus, stop member  25  should be configured to impinge base member  20  only when extended gap width G E  is slightly larger than the width of the clamped portion of the largest box desired to be clamped. 
         [0030]    Typically, clamping forces of at least about 0.1 lb are satisfactory to grip a typical quick service restaurant clamshell sandwich box B, and that forces no greater than about 1.5 lbs will not damage or undesirably deform a typical clamshell sandwich box B. The inventors have also noted that a container holder  10  with prongs  14  and  16  that may be adjusted to a range of gap widths of from about 2.5 inches to about 6.0 inches will accommodate a substantial variety of typical fast-food clamshell sandwich boxes B. Thus, container holder  10  typically provides a clamping force F between prongs  14  and  16  that remains within the range of from about 0.1 pound to about 1.5 pounds over a range of gap widths between prongs  14  and  16  of from about 2.5 inches to about 6.0 inches. 
         [0031]    However, it should be noted that, although the illustrated container holder  10  is shown as used for holding boxes B, holders and methods of using holders for gripping any items of varying size firmly enough to hold the items, without gripping them too firmly, are included in the present invention. To accommodate such other items, appropriate adjustments may be made to the useful range of gap widths and the optimal range of clamping forces, as well as to the shape of prongs  14  and  16  or other suitable gripping members, without departing from the essential scope and spirit of the invention. 
         [0032]    Referring to  FIG. 9 , an alternative manner in which a movable prong  14 ′ may be mounted to a back plate  18 ′ within the scope of the invention is illustrated. In this embodiment, a variable-force spring  12 ′ is employed in place of substantially constant-force spring  12 . In the illustrated example, variable-force spring  12 ′ is a helical spring that is connected to movable prong  14 ′ at spring post  34 ′ and to back plate  18 ′ at spring post  70  by spring hooks  72 . A helical spring in tension typically provides a variable tensile force that increases as the spring is extended beyond its relaxed length. For example, the tensile force is often approximated as being directly proportional to the difference between the extended and relaxed lengths. However, container holders incorporating such springs are within the scope of the present invention, to the extent that they provide a preferred range of clamping forces over a useful range of gap widths between their gripping members. It should also be noted that, even when employing a variable-force spring, the effect of force variation can be minimized by “preloading” the spring to an initial tension that is much greater than the variation in tension due to spring extension resulting from normal use, so that the variation in tension is rendered relatively insignificant. Thus, a preloaded variable-force spring could be advantageously employed in the present invention in place of a substantially constant-force spring. 
         [0033]    While the invention has been described with respect to certain preferred 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.

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