Abstract:
A box includes a floor and at least two pairs of opposing sidewalls extending upwards from the floor in the vertical direction. The sidewalls are arranged foldably with respect to the floor and may be locked with each other in their upfolded position. At least one of the sidewalls includes an unlocking mechanism which is movable between a rest position and an unlocking position in which the locking of the sidewalls is undone. The unlocking mechanism includes at least one pretensioning element which pretensions the unlocking mechanism into its rest position and includes a first end connected to the unlocking mechanism or the sidewall and a second, free end.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of copending International Application No. PCT/EP2011/051946, filed Feb. 10, 2011, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a box for transporting goods, in particular to a foldable box and here to a pretensioning mechanism for an unlocking mechanism. 
     In the known technology, boxes for transporting goods are known, wherein such boxes are implemented foldably in order to define a small volume in a down-folded state so that a plurality of non-used empty boxes may be transported together on a pallet, wherein the number of the boxes transported together in the down-folded state is substantially higher than the possible number of boxes which may not be folded or boxes which are in an up-folded state. Such boxes are, for example, used for the transport of vegetables or fruit but also for the transport of other goods from a manufacturer to a buyer, wherein after their arrival at the buyer, the boxes are either used for the presentation of the goods in sales rooms or are emptied. As soon as the goods have been removed from the boxes, for example by selling the same, the boxes are used again. 
     During transport from the manufacturer to the buyer, the boxes are in the up-folded state and contain goods, for example fruit or vegetables, and when returning the same the boxes are down-folded in order to reduce the volume of same and thus, as mentioned above, be able to transport a large number of boxes at the same time. 
       FIG. 1  shows a schematic illustration of such a known box. The box includes a floor  10  and four side walls  12 ,  14 ,  16 ,  18 . One pair of sidewalls is opposite to each other and as illustrated in  FIG. 1  the box includes two short sidewalls  12  and  14  which are opposite to each other and two long sidewalls  16  and  18  which are opposite to each other. The dimensions of the short and long sidewalls are generally selected depending on the transport pallets, wherein several such boxes are arranged in one layer. In the European area for example three such boxes are arranged adjacent to each other with their long sides and on one of the short sides of the series of arranged boxes, two boxes are arranged in a transverse way whose short side surfaces are adjacent. 
     At least two opposing side walls include grip holes so that the box may be gripped and carried. In the example illustrated in  FIG. 1 , each of the side walls  12  to  18  includes a corresponding grip opening  20 ,  22 ,  24 ,  26 . The side walls  12  to  18  are arranged foldably with respect to the floor  10 , i.e., the side walls  12  to  18  may be folded onto the floor  10  so that the volume of the box is reduced to a minimum for their transport back. It may, for example, be provided to first fold the short side walls  12  and  14  onto the floor  10  and subsequently turn down the long side walls  16  and  18 , wherein in such a case the joints for the short side walls are arranged lower than the joints for the long side walls so that e.g., the floor in the area of the long side walls  16  and  18  has a higher frame than in the area of the short side walls  12  and  14 . 
     For bringing about the necessitated stability of the up-folded box the side walls  12  to  18  may be locked with respect to each other, wherein in the example illustrated in  FIG. 1  a locking of the end surfaces  12  and  14  to the neighboring ends of the long sides  16  and  18  takes place. The short side walls  12  and  14  may comprise one or several protrusions which engage corresponding recesses in the side walls, wherein the side walls then comprise protrusions having corresponding recesses accordingly directing into the direction of the inner side of the box. In addition to these elements, a locking element is provided by means of which the side walls are locked with respect to each other in their up-folded position. In  FIG. 1 , corresponding locking elements are schematically designated by reference numerals  28 ,  30 ,  32  and  34  at the upper corners of the box. The locking elements  28  to  34  each include two elements, for example a fixed element provided on the protrusions of the long side walls  16  and  18 , which may engage a further element provided at the short side walls  12  and  18 . For locking and unlocking the corresponding element of the short side walls  12  and  14  is implemented movably, i.e., movable between a locked position in which the element engages the elements of the long side walls and an unlocked position in which no engagement of the elements takes place so that the short side walls may be folded into the direction of the interior of the box. 
     In order to enable a movement of the moving elements of the short sides  12  and  14 , each of the short sides additionally includes an unlocking mechanism  36 , wherein in  FIG. 1  only the unlocking mechanism of the short side  12  is illustrated, the short side  14 , however, comprises a corresponding mechanism. The unlocking mechanism  36  includes an unlocking bar  38  extending across the short side wall  12 . The unlocking bar  38  includes two ends  40  and  42  at which the unlocking bar  38  is connected to the corresponding locking elements  28  and  30  of the short side  12 . In the example illustrated in  FIG. 1 , the unlocking bar  38  extends from its first end arcuately downward in the direction of the floor  10  and then in parallel to the floor below the grip opening past the same in order to then again extend upwards in a curved manner towards the second end  42 . The short side wall includes two guiding grooves  44  and  46  in which the unlocking bar  38  is guided by means of guide pins  48  and  50 . In  FIG. 1 , the unlocking bar is illustrated in its rest position in which the unlocking bar cooperates with the locking element such that the same are in their locked position. In order to cause an unlocking of the locking elements  28  and  30 , the unlocking bar is moved upwards, i.e., in a vertical direction upwards when seen from the floor, whereby the locking elements of the side wall connected to the ends  40  and  42  of the unlocking bar get out of engagement from the corresponding locking elements of the side walls  16  and  18  so that an unlocking was executed and turning down the side wall is enabled. 
     As a secure locking is desired in the up-folded state of the box, it is necessitated to only enable a movement of the locking bar  38  in the unlocked position when this is desired, in particular a movement into the unlocking position, for example due to a shock or impact or the like is to be prevented. 
     For this reason, the known box according to  FIG. 1  includes the pretensioning elements  52  and  54  which extend between the unlocking bar  38  and an upper frame  56  of the side wall  12 . The pretensioning elements  52  and  54  are integrally connected to the unlocking bar  38 . Further, the upper ends of the pretensioning elements  52  and  54  are mounted to a bottom side of the upper frame. Between the mounting points, an inclined portion of the pretensioning elements  52  and  54  extends so that the opposing end points of the pretensioning elements are arranged spaced apart from each other in the transverse direction of the side wall, whereby the necessitated restoring force is provided with a movement of the unlocking bar  38  into its unlocking position into the direction of the rest position. 
     With a movement of the unlocking bar into the above mentioned unlocking position, the inclined portion between the end points of the pretensioning elements  52  and  54  is extremely stressed as the two are mounted on both sides so that it turned out with boxes implemented according to  FIG. 1  that after a finite number of transport cycles which each include upfolding and downfolding the box a break of the inclined portion of the pretensioning element took place so that a secure locking of the box by holding the unlocking bar in its rest position is not guaranteed over time with such boxes. 
     SUMMARY 
     According to an embodiment, a box may have: a floor; and at least two pairs of respectively opposing sidewalls extending upwards from the floor in a vertical direction, wherein the sidewalls are arranged foldably with respect to the floor and may be locked to each other in their upfolded position, wherein at least one of the sidewalls includes an unlocking mechanism which is movable between a rest position and an unlocking position in which locking of the sidewalls is undone, wherein the unlocking mechanism includes at least one pretensioning element pretensioning the unlocking mechanism into its rest position and including a first end connected to an unlocking bar of the unlocking mechanism and a second, free end, wherein the at least one sidewall includes an upper frame, wherein the movement of the unlocking mechanism from the rest position into the unlocking position includes a movement into the direction of the upper frame, and wherein the free end of the pretensioning element is applied to a bottom side of the upper frame or to an upper side of the unlocking mechanism, both in the rest position and also in the unlocking position of the unlocking mechanism, and wherein the upper frame includes a protrusion extending downwards in an area in which the free end of the pretensioning element is applied to its bottom side, wherein the free end is arranged in the direction of the interior of the box behind the protrusion. 
     Embodiments of the invention provide a box having a floor and at least two pairs of respectively opposing side walls extending upwards from the floor in a vertical direction, wherein the side walls are arranged foldably with respect to the floor and may be locked with each other in their up-folded position, wherein at least one of the side walls includes an unlocking mechanism which may be moved between a rest position and an unlocking position in which the locking of the side walls is undone, wherein the unlocking mechanism includes at least one pretensioning element which pretensions or pre-loads the unlocking mechanism into its rest position and includes a first end connected to the unlocking mechanism or the side wall and a second, free end. 
     Embodiments of the invention provide a box having a floor, at least two pairs of opposing side walls extending upwards from the floor in the vertical direction, wherein the side walls are arranged foldably with respect to the floor, wherein the side walls may be locked to each other in their up-folded position, wherein at least one of the side walls includes an unlocking mechanism which is moveable between a rest position and an unlocking position in which the locking of the side walls is undone, wherein the unlocking mechanism includes at least one pretensioning element which is formed integrally with the unlocking mechanism and wherein an end of the pretensioning element facing away from the unlocking mechanism is free and applied to one portion of the side wall in order to pretension the unlocking mechanism into its rest position. 
     According to embodiments of the invention, one side wall includes a first locking element which cooperates with a second locking element of a neighboring side wall to lock the side wall and the neighboring side wall in the up-folded position, wherein the unlocking mechanism cooperates with the first locking element so that a movement of the unlocking mechanism in its unlocking position causes an unlocking of the first and second locking elements, wherein the unlocking mechanism returns into its rest position without actuation due to the pretensioning element. According to this embodiment, it may be provided for the one side wall to include an upper frame, wherein the movement of the unlocking mechanism from the rest position into the unlocking position includes a movement into the direction of the upper frame, and wherein the free end of the pretensioning element is applied to a bottom side of the upper frame both in the rest position and also in the unlocking position of the unlocking mechanism. The upper frame may include a protrusion extending upwards in an area in which the free end of the pretensioning element is applied to its bottom side, wherein the free end is arranged in the direction towards the interior of the box behind the protrusion. 
     Further, according to embodiments, the at least one side wall may include a wall section in which the thickness is smaller than the thickness of the upper frame and which extends from the upper frame downwards, wherein the free end of the pretensioning element is arranged between the protrusion and the wall section. 
     The protrusion element may have a thickness which corresponds to the thickness of the upper frame minus the thickness of the wall section, wherein the thickness of the free end of the pretensioning element is smaller than the thickness of the rest of the pretensioning element. 
     The thickness of the free end of the pretensioning element may basically correspond to the thickness of the upper frame minus the thickness of the wall section and minus the thickness of the protrusion. 
     According to embodiments of the invention, the pretensioning element is made from the same material as the unlocking mechanism, wherein the pretensioning element includes a first basically vertical section arranged at the unlocking mechanism, a second inclined section which extends between the first section and the protrusion and a third section basically vertical in the rest position of the unlocking mechanism which extends from the second portion or section to the free end of the pretensioning element. 
     According to further embodiments, the pretensioning element may be configured such that no pretension is exerted on to the unlocking mechanism in the rest position and that with a movement of the unlocking mechanism from the rest position in the direction of the unlocking position, an increasing tension in the direction of the rest position is caused. 
     According to embodiments, a side wall may comprise at least one guide opening in which a guiding element of the unlocking mechanism is arranged, wherein the guide opening defines a movement between the rest position and the unlocking position. 
     According to further embodiments, two opposing side walls each include one unlocking mechanism, wherein the unlocking mechanism includes one unlocking bar which extends in a transverse way across the side walls between the bolts and includes two pretensioning elements arranged symmetrically with respect to the center of the side walls. 
     According to the invention, a box is provided wherein the above mentioned problems of known boxes are avoided in connection with the pretensioning element, in particular a breaking of the same. This is achieved by the pretensioning element being only mounted to the unlocking mechanism, for example the unlocking bar and comprising a free end which is only applied to a bottom side of the upper frame of the side wall. This causes the pretensioning element not to be firmly clamped between the upper frame and the moveable unlocking bar any more, rather its free end facing away from the unlocking bar, with respect to a movement of the unlocking bar into the unlocking position which usually is a movement which is vertical with respect to the box floor upwards, may execute both a lateral and also a vertical movement whereby the stress onto the pretensioning element, in particular a stress onto its central section is reduced and thus a breaking of the pretensioning element is prevented even after a plurality of cycles during which locking and unlocking took place. Alternatively, one end of the pretensioning element may be mounted to the side wall or to the upper frame and the other free end is applied to the unlocking bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will be detailed subsequently referring to the appended drawings, in which: 
         FIG. 1  shows a schematic illustration of a known box; 
         FIG. 2  shows a top view onto a side wall of a box as described, for example, with reference to  FIG. 1 , which includes a pretensioning mechanism according to embodiments of the invention; 
         FIG. 3  shows an enlarged illustration of the left hand pretensioning element of  FIG. 2 ; 
         FIG. 4  shows a section of the locking mechanism without the elements of the side wall; and 
         FIG. 5  shows a cross-section along line  5 - 5 ′ in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description of the embodiments of the invention like or seemingly like elements are provided with the same reference numerals. It is further noted that those elements of the box which were already described with reference to  FIG. 1  are provided with the same reference numerals in the following description of the embodiments of the invention, wherein a renewed description of the elements already described with reference to  FIG. 1  is omitted. 
       FIG. 2  shows a top view onto a side wall of a box as it was, for example, described with reference to  FIG. 1 , which includes a pretensioning mechanism according to embodiments of the invention. The side wall illustrated in  FIG. 2  may be one of the short side walls, wherein here, for example, a short side wall  12  of a box is illustrated which was described with reference to  FIG. 1 . It is to be noted here that the opposing short side  14  may have the same or a similar structure. Likewise, it may be provided to provide the unlocking mechanism on the long side walls  16  and  18 . 
     In  FIG. 2 , next to the side wall  12 , an edge  16   a  of the side wall  16  and an edge  18   a  of the side wall  18  is illustrated. The edge  18   a  includes a region which is not illustrated in more detail which overlaps an edge region or area of the short side wall  12 , wherein the overlapping areas comprise recesses and protrusions which engage in order to thus cause a stable connection between the side walls in the locked state. In the upper corner area in which the side walls  12  and  16  or  12  and  18 , respectively, abut locking mechanisms  28  and  30  are illustrated schematically. In the situation illustrated in  FIG. 2 , the elements  28  and  30  are in their locked position, i.e., turning down the side wall  12  onto the floor  10  is not possible due to the locking.  FIG. 2  further shows the unlocking bar  38  and its two opposing ends  40  and  42  connected to the locking elements of the locking mechanisms  28  and  30  associated with the side wall  12 . Further, the pretensioning elements  52  and  54  are illustrated schematically which extend between the unlocking bar  38  and a bottom side of the upper frame  56  of the side wall  12 . 
     In contrast to the example described with reference to  FIG. 1 , however, it is provided according to embodiments of the invention for the pretensioning elements which are, for example, manufactured from the same material as the unlocking bar, to be manufactured integrally with the unlocking bar or to be firmly connected to the same (e.g., bonded, screwed, riveted or the like), wherein the ends facing the upper frame  56  are free, i.e., these ends are not firmly connected to the bottom side or to another part of the upper frame  56  or the side wall  12 . The pretensioning elements  52  and  54 , in the rest position of the unlocking bar  38  illustrated in  FIG. 2 , are also in their rest position, which means that the same are in their relaxed or unbent position, i.e., exert no pretension in the direction of the box floor  10 . The pretensioning elements  52  and  54  may for example be manufactured together by a suitable plastics forming process in one work cycle or operation, for example using a common mold whereby the manufacturing of the pretensioning elements and the unlocking bar is enabled integrally. 
     If the unlocking bar is now moved in a direction upwards, i.e. in a direction away from the floor  10  of the box, the pretensioning elements  52  and  54  are deformed such that their central portions, the inclined portions illustrated in  FIG. 2 , are deformed into the direction of the box floor. The front, free ends of the pretensioning elements  52  and  54  are moved outwards along the bottom side of the upper frame  56  and simultaneously the central portions are deformed, whereby a restoring force for the unlocking element in the direction of its rest position is generated so that unlocking is only possible by overcoming the corresponding spring force or pretensioning force of the pretensioning elements for unlocking. By this, locking during transport is guaranteed, and also when the locking element is unintentionally lifted, the same returns into a locked position after the actuation of the element  38  is over. 
     As it may further be seen from  FIG. 2 , the upper frame  46  includes protrusions  58  and  60  which extend from a bottom side of the upper frame  46  in the region downwards in which the free ends of the pretensioning elements  52  and  54  are in contact with the bottom side of the upper frame  56 . The sidewall  12  includes a wall section  62  which extends originating from the upper frame  56  downward in the direction of the floor  10 . The wall section  62  has a thickness which is smaller than the thickness of the upper frame  56 . On one side of the sidewall  12  directed into the direction of the interior of the box the wall section  62  is flush with a back surface of the upper frame  56 , whereby the wall section  62  on the exterior side of the sidewall  12  returns or jumps back with respect to a front surface of the upper frame  56 . The protrusions  58  and  60  extend from a front surface of the upper frame  56  downward, so that between the protrusion  58 ,  60  and the wall  62  a free space results in which the free end of the pretensioning elements  52  and  54  is arranged. Due to this arrangement, guiding the free end of the pretensioning elements is achieved, in particular guiding in the transverse direction of the sidewall  12 , wherein in particular a movement in the direction perpendicular to the wall surface of the sidewall  12  is prevented. 
       FIG. 3  shows an enlarged illustration of a part of  FIG. 2 , i.e. of the left pretensioning element. It is to be noted here that also the right-hand pretensioning element  52  is implemented accordingly. The pretensioning element  54  includes a first vertical section  64  which is integral with the unlocking bar  38  or is mounted to the unlocking bar  38  adjacent to the guide pin  50 . The pretensioning element  54  further includes the inclined central section  66  already mentioned above which extends from the first section  64  to the protrusion  60 . The free end of the element  54  is hidden behind the protrusion  60  in  FIG. 3  but is, as already mentioned, not mounted to the upper frame  56  but may move along its bottom side behind the protrusion  60  in the lateral direction, so that with an upward movement of the element  38  a corresponding movement of the section  66  of the pretensioning element  54  may take place downward along the curved arrow  68 . By this, a corresponding restoring force is generated which acts upon the unlocking element  38  to force the same back into its rest position. 
       FIG. 4  shows a section of a locking mechanism without the elements of the sidewall  12 . The locking mechanism includes the unlocking bar  38  and the pretensioning element  54 . Next to the first and second section  64  and  66  now also the free end  70  of the pretensioning element  54  may be seen, wherein the pretensioning element  54  includes a third section  72  which extends originating from the second section in the rest position of the pretensioning element, in which no force is exerted onto the same, basically perpendicularly upwards up to the free end  70 . The third section of the pretensioning element has a thickness, according to embodiments, which is smaller than the thickness of the first and second section of the pretensioning element  54 , wherein the thickness of the first and second section of the pretensioning element may be selected so that the same corresponds to a thickness of the upper frame  56  minus the thickness of the wall section  62 , so that when the unlocking mechanism is installed its front surface which is facing outward is basically flush with a front surface of the upper frame which is facing outward (see reference numeral  56   a ). In contrast to that, the thickness of the third section  72  is reduced, wherein the same is smaller according to embodiments than the thickness of the upper frame  56  minus the thickness of the wall section  62  minus the thickness of the protrusion  60 . 
       FIG. 5  shows a sectional view along line  5 - 5 ′ in  FIG. 3  and shows how the free end  70  of the pretensioning element  54  is formed in the gap formed between the protrusion  60  and the wall  62 . The free end  70  is not connected to the upper frame  56  but is applied to its bottom side  56   b  and may move along this bottom side in the lateral direction. 
     Embodiments were described with reference to  FIGS. 2-5  of the invention, wherein it is noted, however, that the present invention is not limited to the described implementation of the unlocking mechanism. Rather, also different implementations of the unlocking mechanism may be provided which operate such that a movement from a rest position into an unlocking position is provided wherein a corresponding restoring force into the rest position is necessitated which is then achieved using the inventive approach, i.e. using a pretensioning element which comprises the two ends, one end of which is either mounted to the sidewall or to the unlocking element, e.g. formed integrally with the same, and the other end is free. Further, in embodiments separate unlocking mechanisms may be provided instead of the common unlocking bar  58  which have to be operated separately in order to cause the unlocking. 
     Embodiments of the invention were described above with reference to a pretensioning element whose end facing the unlocking bar is formed integrally with the same. It is to be noted that the pretensioning element may be mounted to the bar  38  by suitable means (e.g. screws, bonding, riveting), instead by the integral connection. It may alternatively be provided to mount the pretensioning element to the bottom side or to another suitable position of the upper frame  56  or the sidewall  12  with one end so that its free end acts upon a surface of the unlocking bar  38 , whereby a functionality of the same effect is achieved as it was explained above. 
     According to embodiments the box may be closed by actuating the bolt so that the corresponding wall is released for being turned down or folded down onto the box floor. Alternatively, or additionally, the locking mechanism may be implemented to allow an unlocking when a predetermined force is exerted onto the wall. Embodiments may thus include the spring pretensioned locking mechanism which was described above which comprises a movable fixing or latching element which may be latched to a protrusion of the neighboring wall, wherein the protrusion and/or the latching element comprises contact surfaces which are inclined with respect to the vertical direction in the upfolded state such that the locking mechanism opens against its spring pretensioning when exceeding a predetermined force directed inwards and exerted upon the wall, as it is for example described in WO 2010/11907381 A1. 
     The above described embodiments only represent an illustration of the principles of the present invention. It is obvious that modifications and variations of the arrangements and details described herein are obvious to other persons skilled in the art. It is thus the purpose for the invention only to be limited by the protective scope of the following patent claims and not by the specific details which were presented herein with reference to the description and the explanation of the embodiments. 
     While this invention has been described in terms of several advantageous embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.