Abstract:
Suitably configured sheets of material and related folding methods provide self-latching clamshell folded boxes that may be used, for example, to securely package consumer goods such as shoes or other clothing items.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 61/529,464 filed Jan. 30, 2012 and titled “Sheet and Folding Method For Self-Latching Clamshell Folded Box”, which is incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to self-latching containers for packaging, e.g., consumer goods. 
     BACKGROUND 
     Consumer goods of various sorts such as shoes or other clothing items, for example, may be packaged for shipping, storage, and sales in lidded containers. During such shipment, storage, or sales, such containers may be inadvertently up-ended, with the possibility that the container lid may open and the consumer good may spill from the container. 
     SUMMARY 
     Suitably configured sheets of material and related folding methods provide self-latching clamshell folded boxes that may be used, for example, to securely package consumer goods such as shoes or other clothing items. 
     In one aspect, a sheet of material is configured to be folded into a self-latching clamshell box. The sheet of material comprises a tray section comprising fold lines defining a rectangular tray bottom panel, first and second tray side panels attached to and on opposite ends of the tray bottom panel, a tray front panel attached to a front end of the tray bottom panel, a tray back panel attached to a back end of the tray bottom panel opposite from the front end of the tray bottom panel, a first latching tab attached to an outer front corner of the first tray side panel, and a second latching tab attached to an outer front corner of the second tray side panel. 
     The sheet of material also comprises a lid section comprising fold lines defining a rectangular lid top panel, a lid front panel attached to the lid top panel opposite from the tray back panel, and a lid front roll-over panel attached to the lid front panel. The lid front roll-over panel comprises notches in two outer corners. A back end of the lid top panel is defined by a fold line between the lid top panel and the tray back panel. 
     The tray section fold lines are configured such that the first and second tray side panels, the tray front panel, and the tray back panel may each be folded about 90 degrees with respect to the tray bottom panel about respective fold lines to form, respectively, first and second tray side walls, a tray front wall, and a tray back wall of a tray portion of the clamshell box. The first and second latching tabs may be folded about 180 degrees with respect to the first and second tray side panels, respectively, about respective fold lines to form first and second protrusions extending outward from the tray front wall (e.g., away from the tray back wall) at opposite ends of the tray front wall. The lid section fold lines are configured such that the lid front roll-over panel may be folded about 180 degrees with respect to the lid front panel about a respective fold line, and the lid front panel and the lid front roll-over panel may be folded about 90 degrees with respect to the lid top panel about a respective fold line to form a lid front wall of a lid portion of the clamshell box. The lid front wall then comprises inner recesses formed by the notches in the lid front roll-over panel. The fold line between the tray back panel and the lid top panel is configured to form a clamshell hinge about which the folded lid portion may be rotated to close the clamshell box, with the protrusions on the tray front wall of the folded tray portion engaging the inner recesses in the lid front wall of the lid portion to latch the lid portion to the tray portion. 
     In another aspect, a sheet of material is folded by a method as summarized above to form a self-latching clamshell box. 
     In the self-latching clamshell boxes of the above aspects, the latching mechanism formed by the protrusions in the tray front wall and the recesses in the lid front wall may latch the box sufficiently securely that an upside-down empty box remains closed even after having been previously opened about five times, for example. 
     The self-latching clamshell boxes of the above aspects may be dimensioned and configured, for example, to contain shoes. 
     These and other embodiments, features and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following more detailed description of the invention in conjunction with the accompanying drawings that are first briefly described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1C  show, respectively, a schematic drawing of an example sheet of material configured for folding into a self-latching clamshell box ( FIG. 1A ), a schematic diagram of the same sheet of material partially folded to provide latching protrusions on a tray portion and complementary recesses on a lid portion ( FIG. 1B ), and a perspective view of a corner of the clamshell box showing an example latching protrusion ( FIG. 1C ). 
         FIG. 2  shows a schematic drawing of another example sheet of material configured for folding into a self-latching clamshell box. 
         FIGS. 3A-3L  show perspective views depicting steps in an example method of folding the sheet of material of  FIG. 2  into a self-latching clamshell box. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description should be read with reference to the drawings, in which identical reference numbers refer to like elements throughout the different figures. The drawings, which are not necessarily to scale, depict selective embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention. 
     This specification describes sheets of material configured to be folded along fold lines into self-latching clamshell boxes, and related folding methods. As used in this specification and the claims, the term “fold line” refers to a line in a sheet of material about which the sheet of material has been predisposed to fold. Such predisposition may be induced, for example, by slitting, scoring, or creasing the sheet of material along the fold line, or by any other suitable method. Fold lines are depicted in the figures by thick or bold lines to distinguish them from thinner lines defining the edges of the sheets or defining cut lines in the sheets. Also as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. 
     Referring now to  FIG. 1A , an example sheet of material  10  configured for folding into a self-latching clamshell box comprises a tray section  15  and a lid section  20 . Tray section  15  comprises fold lines  25  defining tray bottom panel  30 , tray side panels  35 , tray front panel  40 , and tray back panel  50 . Side panels  35 , front panel  40 , and back panel  50  may be folded by about 90 degrees around their respective fold lines and secured to each other in any suitable manner to form corresponding walls of a tray portion of the clamshell box. The panels may be secured to each other, for example, with tape, adhesive, or any suitable fastener. Alternatively, or in addition, the panels may be secured to each other using folding and tab and slot methods as described further below (FIGS.  2  and  3 A- 3 L), for example, in which case sheet  10  may comprise additional panels and features. 
     Tray section  15  also comprises fold lines  55  defining latching tabs  60 . As best seen in  FIG. 1B  and  FIG. 1C , latching tabs  60  may be folded about 180 degrees around fold lines  55  to lie flat against tray side panels  35 , providing double sheet thickness latching protrusions  65  extending outward from the tray wall (e.g., away from the tray back wall). As depicted in  FIG. 1C , latching protrusions  65  may each have, for example, an edge  70  sloping downward and away from the tray front wall and an edge  75  returning toward the tray front wall. As further described below, latching protrusions  65  may engage recesses in a lid portion of the clamshell box to latch the lid portion to the tray portion. 
     Referring again to  FIG. 1A , lid section  20  comprises fold lines  80  and  85  defining a lid top panel  90  (optionally having dimensions matching those of the tray bottom panel) and folding lines  95  defining lid front panel  100  and lid front roll-over panel  105 . Lid front roll-over panel  105  comprises notches  110  in its outer corners. Lid front roll-over panel  105  may be folded by about 180 degrees around fold lines  95  to lie flat against lid front panel  100 . Lid front panel  100  and lid front roll-over panel  105  may then be folded by about 90 degrees around fold line  85  and secured in position to form a double sheet thickness lid front wall of a lid portion of the clamshell box. Panels  100  and  105  forming the lid front wall may be secured in the 90 degree position, for example, with tape, adhesive, or any suitable fastener. Alternatively, or in addition, panels  100  and  105  may be secured in position using folding and tab and slot methods as described below (FIGS.  2  and  3 A- 3 L), for example, in which case sheet  10  may comprise additional panels and features. 
     Referring again to  FIG. 1B , after panels  100  and  105  are folded as described above, the resulting double sheet thickness lid front wall comprises inner recesses  115  formed by notches  110  in panel  105 . 
     Fold line  80  between tray back panel  50  and lid top panel  90  is oriented to act as a clamshell hinge around which the folded lid portion may be rotated to close the clamshell box, with protrusions  65  in the tray front wall of the folded tray portion engaging inner recesses  115  on the inside of the lid front wall of the lid portion to latch the lid portion to the tray portion. 
     Such sheets of material may be stored or shipped either in a flat configuration or in the folded configuration (i.e., in the form of the self-latching clamshell box), as convenient. 
     Referring now to  FIG. 2 , example sheet of material  120  is also configured to be folded into a self-latching clamshell box. In addition to the features of sheet  10  shown in  FIGS. 1A-1C , sheet  120  includes additional features described below with reference to  FIG. 2  and to  FIGS. 3A-3L . 
       FIGS. 3A-3L  show steps in an example method for folding sheet  120  of  FIG. 2  into a self-latching clamshell box. The tray portion may be folded up as follows. First ( FIG. 3A ), tray front handshake side panels  130  are folded about 90 degrees around fold lines  125 , and tray back handshake side panels  140  are similarly folded about 90 degrees around fold lines  135 . Next ( FIG. 3B ) tray front panel  40  is folded about 90 degrees around the respective fold line  25  to form a tray front wall, tray back panel  50  is folded about 90 degrees around the respective fold line  25  to form a tray back wall, and notches  145  in tray front handshake side panels  130  are engaged with notches  150  in corresponding tray back handshake side panels  140  to secure front handshake side panels  130  to corresponding tray back handshake side panels  140 . In the illustrated variation, tray front handshake side panels  130  tuck to the outside of tray back handshake side panels  140 , but this is optional. Next ( FIGS. 3B ,  3 C,  3 E), latching tabs  60  are folded about 180 degrees to lie flat against the inside surface of side panels  35 . Next ( FIGS. 3B ,  3 C,  3 E), side panels  35  are folded about 90 degrees around respective fold lines  25  to form the tray side walls. Next ( FIGS. 3C-3F ), roll-over side panels  160  are folded about  180  degrees around fold lines  155  to lie flat against the inside of the interengaged handshake panels  130  and  140 , with the handshake panels sandwiched between roll-over side panels  160  and side panels  35 . Next ( FIGS. 3D ,  3 F), roll-over side panel tabs  165  are inserted into corresponding slots  170  in tray front panel  40  and tray back panel  50  to secure the tray side walls to the tray front and back walls. 
     The lid portion may be folded up as follows. First ( FIG. 3G ), lid corner locking flanges  195  are folded about 90 degrees with respect to lid corner panels  180  around fold lines  190 . Next ( FIG. 3G ), lid corner panels  180  are folded about 90 degrees with respect to lid side panels  185  around fold lines  175 . Next ( FIG. 3H ), lid side panels  185  are folded about 90 degrees around fold lines  173  to form lid side walls and to form (in combination with lid corner panels  180 ) front corners of the lid portion of the clamshell box. Lid corner locking flanges  195  are then flush with lid top panel  90 . Next ( FIG. 3I ), lid front panel  100  and lid front roll-over panel  105  are folded by about 90 degrees around fold line  85  to form a lid front wall. Next ( FIGS. 3I-3K ), roll-over lid panel  105  is folded about 180 degrees around fold lines  95  to lie flat against the inside of lid corner panels  180 , which are sandwiched between roll-over lid panel  105  and lid front panel  100 . Next ( FIGS. 3I-3K ), roll-over lid panel locking tabs  200  are inserted into lid corner locking flanges  195  to secure the lid front wall in position with respect to the lid top and side walls. The lid portion may then be rotated about the clamshell hinge provided by fold line  80  to engage recesses  115  with protrusions  65  to latch the lid portion to the tray portion of the self-latching clamshell box ( FIG. 3L ). 
     Referring again to  FIGS. 1A ,  1 B, and  2 , reference numerals A-E depicted in these figures identify the following dimensions: A—tray bottom width parallel to the clamshell hinge, B—tray bottom width perpendicular to the clamshell hinge, C—tray bottom depth, D—length of the blank (sheet of  FIG. 2 ), and E—width of the blank (sheet of  FIG. 2 ). In one variation, A is about 143 millimeters (mm), B is about 123 mm, C is about 63 mm, D is about 458 mm, and E is about 366 mm. In another variation, A is about 329 mm, B is about 126 mm, C is about 106 mm, D is about 569 mm, and E is about 638 mm. In another variation, A is about 347 mm, B is about 327 mm, C is about 123 mm, D is about 10005 mm, and E is about 747 mm. 
     More generally, A may be for example about 143 mm to about 405 mm, B may be for example about 91 mm to about 327 mm, C may be for example about 63 mm to about 143 mm, D may be for example about 458 mm to about 1005 mm, and E may be for example about 366 mm to about 788 mm. 
     The material used for the foldable sheets described herein may be or comprise, for example, corrugated fiberboard comprising a fluted corrugated sheet (e.g., E flute) sandwiched between liner boards, corrugated plastic board comprising a fluted corrugated sheet sandwiched between liner boards, or any other suitable corrugated or uncorrugated material (e.g., uncorrugated paperboard). Where the sheet comprises corrugated material, the flutes may be preferably aligned perpendicularly to the clamshell hinge. 
     This disclosure is illustrative and not limiting. Further modifications will be apparent to one skilled in the art in light of this disclosure and are intended to fall within the scope of the appended claims. For example, where methods and steps described above indicate certain events occurring in certain order, those of ordinary skill in the art will recognize that the ordering of certain steps may be modified and that such modifications are in accordance with the inventions disclosed herein. Additionally, certain of the steps may be performed concurrently in a parallel process when possible, as well as performed sequentially as described above. Acts referred to herein as operations in a method or process may also be understood as “steps” in the method or process. Therefore, to the extent there are variations of the inventions disclosed herein, which are within the spirit of this disclosure or equivalent to the inventions disclosed herein, it is the intent that this disclosure and the claims it supports will cover those variations as well.