Abstract:
A mattress frame that occupies a small volume and can be used by a recipient without having to assemble the frame. The frame has four connected sides and is made of foam. The frame is rectangular in shape and has two longer sides and two shorter sides. The two shorter sides are folded in a U shape so that a bow-tie-shaped frame results. The bow-tie-shaped frame is rolled and packaged in a container. The frame can be rolled to form a spiral or an M-shape. A recipient of the rolled frame removes the frame from its packaging and the frame expands to its intended shape.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on and hereby claims the benefit under 35 U.S.C. §119 from Chinese Patent Application No. 200620060015.8, filed on Jun. 1, 2006, in China, the contents of which are hereby incorporated by reference. This application is a continuation-in-part of Chinese Application No. 200620060015.8. 
     TECHNICAL FIELD 
     The present invention relates generally to mattresses, and more particularly to a compressible frame for a mattress. 
     BACKGROUND 
     New types and forms of mattresses and mattress accessories continue to be developed for traditional bedroom use, as well as for such diverse uses as camping, boating and recreational vehicle traveling. For example, some mattresses provide support against weight using springs, some mattresses are filled with air, some mattresses are filled with water, whereas some mattresses are made of memory foam or have a layer of memory foam to provide support against weight. 
     When weight is applied against an edge of a mattress, the mattress deforms and does not provide support. Mattress deformation is particularly a problem for air mattresses. Rigid frames that surround the mattress are used to provide support at the edges of a mattress and provide support against weight placed at the edge of a mattress. 
       FIG. 1  (prior art) is a perspective view of a prior art frame structure used to support edges of a mattress. The frame attachment structure includes first side  10 , second side  12 , third side  14  and fourth side  16 . First side  10  and third side  14  are substantially the same in size and second side  12  and fourth side  16  are substantially the same in size. The first side  10 , second side  12 , third side  14  and fourth side  16  are made of a foam material. A cloth  20  or other material such as plastic is affixed to each of first side  10 , second side  12 , third side  14  and fourth side  16  so that each side stays in place relative to other sides. The first side  10 , second side  12 , third side  14  and fourth side  16  provide a frame for a mattress. For example, the mattress would be placed underneath cloth  20  so that if no other cover is used, a person would contact cloth  20  when sitting on the mattress. 
     To package the frame structure of  FIG. 1  for shipping, the sides are folded inward but maintain a connection with cloth  20 . The resulting structure has both length and width larger than a size of the mattress it is to surround, which can consume too much space during transportation. 
     One drawback with this frame structure of  FIG. 1  is that the frame is bulky and takes up more space than desired during transportation. It is desirable to minimize the size of goods during transportation in order to reduce costs and increase the amount of goods that can be transported. In addition, the process of mounting the sides to cloth  20  can be complicated, and gaps are present in the frame so that the evenness of support of edges of a mattress may not be acceptable to a user. 
       FIG. 2  (prior art) is a perspective view of another prior art frame structure. The frame structure includes first side  10 , second side  12 , third side  14  and fourth side  16 . In this structure, however, four replicas of corner  24  are used so that sides are set in place. Each corner  24  has two inlets and each inlet receives a side so that sides are formed ninety (90) degrees from each other. The mattress is placed inside the boundaries of the sides. 
     To package the frame structure of  FIG. 2  for transporting, the sides are disconnected from each corner  24  and the sides are placed together and separate from the corners. The resulting structure that is to be shipped has a length larger than a size of the mattress it is to surround, which can consume too much space during transportation. 
     One drawback with the frame structure of  FIG. 2  is that it consumes too much space during transportation. In addition, the user of the frame has to construct the frame, which may dissuade customers from purchasing the frame. In addition, the frame does not provide uniform support to edges of a mattress because there are different widths of material used to surround a mattress. 
     SUMMARY 
     The following presents a simplified summary of some embodiments of the invention and is not intended to delineate the scope of the invention. This summary presents some embodiments in a simplified form as a prelude to the more detailed description that is presented below. 
     One embodiment includes a compressible mattress frame that can be packaged into a small volume so that it consumes a small volume during transportation. According to one aspect, the frame is formed by injecting chemicals into a mold to form a continuous piece of rigid foam material in the shape of a rectangle. The dimensions of the mold depend on the size of the mattress the frame is to surround. The rigid foam material can be polyurethane foam. In another aspect, the frame is formed by forming a rectangular strip of rigid foam, cutting the strip into four pieces such that each of the four pieces is a side of the frame and then bonding the edges of the pieces together so that the resulting structure is a rectangle shaped frame. In one aspect, the bonding uses an adhesive such as, but not limited to, urethane-based glue. 
     In accordance with another embodiment, the frame structure is compressed so that it takes minimal space during transportation. The shorter sides of the frame are pushed inward from the middle of the shorter sides and the longer sides of the frame are pushed inward so that the resulting structure is bow-tie shaped and has the shorter sides bent in half with each inner portion of the half of the shorter side touching an inner portion of the longer side of the frame. The bow-tie shaped structure is then rolled and compressed and vacuum packed into a plastic cover. The recipient of the frame can remove the rolled and compressed frame from the cover and the shape of the frame restores to a rectangle. The frame can then be placed to surround a mattress. The support provided to edges of a mattress is consistent because the same thickness of material and type of material is used around the frame. 
     Accordingly, a frame is provided that involves no assembly by a user and compresses into a small shape so that it uses little space during transportation. 
     Other embodiments and advantages are described in the detailed description below. This summary does not purport to define the invention. The invention is defined by the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, where like numerals indicate like components, illustrate embodiments of the invention. 
         FIG. 1  (prior art) is a perspective view of a prior art frame structure. 
         FIG. 2  (prior art) is a perspective view of another prior art frame structure. 
         FIG. 3  is a perspective view of a frame in accordance with an embodiment. 
         FIG. 4  is a perspective view of a frame in accordance with an embodiment. 
         FIGS. 5-7  depict an example of how the shape of the frame is changed to reduce the size of a frame to a size suitable for transportation in accordance with an embodiment. 
         FIG. 8  is a flow chart of a suitable process to form a frame having a suitable size for transportation in accordance with an embodiment. 
         FIG. 9  is an example of a placement of a mattress into a frame so that the frame surrounds the mattress in accordance with an embodiment. 
         FIG. 10  is a perspective view of the frame of  FIG. 3  and a mold in accordance with an embodiment. 
         FIG. 11  is a perspective view of a rolled frame that has a cross-sectional M-shape. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings. 
       FIG. 3  is a perspective view of a frame  30  in accordance with an embodiment. Frame  30  is formed to be a rectangular shape having four sides and an opening in the center for insertion of a mattress by injecting chemicals into a mold, such as a mold shown in  FIG. 10 . In one aspect, the mold produces a frame  30  made of a polyurethane foam. For example, the foam can have a density of approximately 0.8-3.0 pounds per cubic foot. The resulting frame  30  has a first side  32 , a second side  34 , a third side  36  and a fourth side  38 . In this embodiment, frame  30  is shaped without joining individual sides. 
       FIG. 4  is a perspective view of a frame  40  in accordance with another embodiment. Frame  40  has a first side  42 , a second side  44 , a third side  46  and a fourth side  48 . In one aspect, a rectangular strip of polyurethane foam is formed having a width (in the Y direction) of the width of each of first side  42 , second side  44 , third side  46  and fourth side  48  (all widths are the same) and having the length of at least of the combined lengths (in the X and Z directions) of first side  42 , second side  44 , third side  46  and fourth side  48 . In one example, the density of the foam is approximately 0.8-3.0 pounds per cubic foot. 
     The piece of foam is cut so that four portions of foam result having the dimensions of first side  42 , second side  44 , third side  46  and fourth side  48 . The sides are joined at the edges using an adhesive  50  such as, but not limited to, Styrene Butadiene Rubber (SBR) glue or urethane based glue to form frame  40  having the desired dimensions. 
     Frames  30  and  40  surround mattresses having various sizes (e.g., twin, full, queen, or king) and thicknesses. Accordingly, the dimensions of frames  30  and  40  in the X, Y and Z directions vary depending on the size of the mattress that frame  30  or  40  is to surround. The thickness of the frame can vary depending on the desired edge support provided for the mattress and/or the density of the frame. 
       FIGS. 5-7  depict an example of how the shape of the frame is changed to reduce the size of a frame to a size suitable for transportation in accordance with an embodiment.  FIG. 5  shows a top view of frame  30 / 40  when it is being manipulated to form the structure  60  of  FIG. 6 . Each of first side  32 / 42 , second side  34 / 44 , third side  36 / 46  and fourth side  38 / 48  have respective inner edges  52 ,  54 ,  56  and  58 . In this example, inner edge  52  of first side  32 / 42  is bent from its middle in a U-shape so that straight sides of the U are placed into contact with inner edges  54  and  58 . Similarly, inner edge  56  of third side  36 / 46  is bent from its middle in a U-shape so that straight sides of the U are placed into contact with inner edges  54  and  58 . The resulting structure is shown in perspective view as structure  60  of  FIG. 6 . Structure  60  has a shape similar to a bow-tie. 
     For example, the thickness of structure  60  can be approximately seventy-five percent less than the combination of thicknesses of sides that are brought into contact. Other compression ratios, however, can also be used. For example, where four sides are stacked as in the left-hand side of structure  60 , the resulting thickness is twenty-five percent of what the combined thicknesses of each of the four sides would have been. 
       FIG. 7  depicts an example of how structure  60  is shaped into a rolled frame  70 . Structure  60  is rolled into a spiral starting at outer edge  62  while maintaining a constant width (the width is shown in  FIG. 6 ). During rolling, structure  60  is also compressed. The rolled and compressed frame is vacuum packed into a plastic cover to form rolled frame  70  having plastic cover  72 . The rolled frame  70  having plastic cover  72  is ready to be transported. 
       FIG. 8  is a flow chart of a suitable process to form a frame having a suitable size for transportation in accordance with an embodiment. In action  100 , a frame having four attached sides is formed. For example, the frame can be formed as described with regard to  FIG. 3  or  FIG. 4 . In action  101 , the shorter sides of the frame are compressed in a U-shape so that inner portions of the shorter side contact the inner portions of the longer sides. The resulting structure is bow-tie shaped and shown in  FIG. 6 . In action  102 , the structure resulting from action  101  is rolled and compressed. In action  103 , the rolled frame is vacuum packed into a container such as a plastic bag. 
       FIG. 9  is an example of a placement of a mattress into a frame  73  so that the frame surrounds the mattress in accordance with an embodiment. The recipient of the rolled frame can remove frame  73  from its packaging and form a frame without assembly. The user can merely unpack the package and frame  73  can restore to its intended inflated state naturally without any extra operation. The mattress is placed within frame  73 . 
     Although certain specific exemplary embodiments are described above in order to illustrate the invention, the invention is not limited to the specific embodiments. Other types of foam and material can be used such as material that is bendable and compressible without breaking or permanently deforming but memorizes its shape so that it restores to its shape prior to being bent or compressed. For example, alternative materials to form one or more sides of the frame can include, but are not limited to, sponge, hydrofluoroalkane (HFA) products, Expanded Polystyrene (EPS), extruded polystyrene foam (XPS), toluene-diisocyanate (TDI) base, and methylene diisocynate (MDI). For example, the shape of rolled frame  70  can be M-shaped, as shown in  FIG. 11 , or ram horn shaped (two spirals) as described in U.S. patent application Ser. No. 11/786,854, “Rolled Memory Foam Bedding Article Having A Plurality Of Roll Portions”, inventor Suk Kan Oh, filed Apr. 13, 2007, which is incorporated by reference herein in its entirety. Accordingly, various modifications, adaptations, and combinations of various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.