Patent Publication Number: US-2005121061-A1

Title: Collapsible sleeping structures

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to collapsible structures, and in particular, to collapsible structures that incorporate a sleeping accessory.  
      2. Description of the Prior Art  
      There are presently many collapsible structures that are being provided for use by children and adults. Examples of these collapsible structures are illustrated in the following patents: U.S. Pat. No. 5,816,954 (Zheng), U.S. Pat. No. 6,006,772 (Zheng), U.S. Pat. No. 5,778,915 (Zheng), U.S. Pat. No. 5,467,794 (Zheng), U.S. Pat. No. 5,975,101 (Zheng), U.S. Pat. No. 5,722,446 (Zheng), U.S. Pat. No. 4,858,634 (McLeese), U.S. Pat. No. 4,825,592 (Norman), U.S. Pat. No. 5,964,533 (Ziglar), U.S. Pat. No. 5,971,188 (Kellogg et al.), and U.S. Pat. No. 5,038,812 (Norman), among others. These collapsible structures are supported by one or more frame members that can be twisted and folded to reduce the overall size of the structure. These collapsible structures can be used in a wide variety of applications, such as containers, tents, play structures, executive toys, shelters, sports structures, and others. As a result, collapsible structures have become very popular.  
      One other possible application for such collapsible structures is for use as a slumber tent, where a sleeping accessory or equipment, such as a sleeping bag, pillow, light futon or mattress, or similar support, is incorporated with the collapsible structure. When a collapsible structure is being adapted for use as a sleeping or slumber tent, ease of use (i.e., convenience) and storage considerations become important. For example, such a structure should provide quick and convenient access to the interior, and should be easy to fold into a smaller configuration for storage.  
      Thus, there still remains a need to provide collapsible sleeping structures that are convenient to use and that are easy to store.  
     SUMMARY OF THE DISCLOSURE  
      It is an object of the present invention to provide a collapsible structure that incorporates a sleeping implement.  
      It is another object of the present invention to provide a collapsible sleeping structure that are convenient to use and to store.  
      In order to accomplish the objects of the present invention, the present invention provides a collapsible structure having at least one foldable frame member having a folded and an unfolded orientation, with a fabric material covering portions of the frame member to form at least one panel when the frame member is in the unfolded orientation, and a mat coupled adjacent the bottom side of at least one of the at least one panel.  
      According to one embodiment of the present invention, the structure has a first panel, a second panel and a third panel, each panel having a foldable frame member that has a folded and an unfolded orientation. The left side of the first panel is hingedly coupled to the right side of the second panel, the right side of the first panel is hingedly coupled to the left side of the third panel, and the left side of the second panel and the right side of the third panel are free of any connections to any panels.  
      According to another embodiment of the present invention, the structure has two frame members, each frame member having a first end and a second end that are adapted to contact a surface, with the two frame members overlapping each other.  
      According to yet another embodiment of the present invention, the structure has a plurality of separate panels that are hingedly coupled to each other.  
      According to yet another embodiment of the present invention, the at least one frame member is a frame member having a figure-eight configuration when in the unfolded orientation, the figure-eight configuration defining a first loop, a second loop, and a crossover that forms the apex of the frame member in the unfolded orientation and with the first and second loops extending downwardly from the apex. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1A  is a perspective view of a collapsible structure according to one embodiment of the present invention.  
       FIG. 1B  is a partial cut-away view of the section A of the structure of  FIG. 1A  illustrating a frame member retained within a sleeve.  
       FIG. 2  is a perspective view of the structure of  FIG. 1A  illustrating a few modifications made thereto.  
       FIGS. 3A-3E  illustrate how the structure of  FIGS. 1A and 2  can be twisted and folded to reduce the structure to a size which is a fraction of the size of the free-standing structure.  
       FIGS. 4-7A  are perspective views of collapsible structures according to different embodiments of the present invention.  
       FIG. 7B  is an expanded view of the section B of the structure of  FIG. 7A .  
       FIG. 8  is a perspective view of the structure of  FIG. 7A  illustrating a few modifications made thereto.  
       FIG. 9  is a perspective view of a collapsible structure according to another embodiment of the present invention.  
       FIGS. 10A-10E  illustrate how the structure of  FIG. 9  can be twisted and folded to reduce the structure to a size which is a fraction of the size of the free-standing structure.  
       FIG. 11  is a perspective view of the structure of  FIG. 10A  illustrating modifications made thereto. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.  
      The present invention provides collapsible structures that incorporate a sleeping implement, such as a sleeping bag, pillow, light futon or mattress, or similar support. As used herein, the terms “hingedly coupled” or “hingedly connected” shall mean to couple two edges or sides by stitching, or by the use of removable attachment mechanisms (such as Velcro™ pads or opposing toggles and loops, among others).  
       FIG. 1A  illustrates a collapsible structure  20  that has three panels  22 ,  24  and  26  that are connected to each other to partially enclose a space. One panel  22  acts as a central panel, and the other two panels  24  and  26  are side panels. The panel  22  has four sides, with a left side  28 , a bottom side  30 , a right side  32  and a top side  34 . Each of the side panels  24  and  26  has a three-sided configuration, with a bottom side  36 , a left angled side  38 , and a right angled side  40 . The right side  40  of the panel  26  is hingedly conected to the right side  32  of the panel  22 , and the left side  38  of the panel  24  is hingedly conected to the left side  28  of the panel  22 . Each panel  22 ,  24  and  26  has a continuous frame retaining sleeve (e.g., see  42  in  FIG. 1B ) provided along and traversing the edges of its sides. A continuous frame member  44  is retained or held within each frame retaining sleeve  42  to support and define the shape of each panel  22 ,  24  and  26 . Only one frame member  44  is shown in  FIG. 1B ; the other frame members are not shown but are the same as frame member  44 .  
      The continuous frame members  44  may be provided as one continuous loop, or may comprise a strip of material connected at both ends to form a continuous loop. The continuous frame members  44  are preferably formed of flexible coilable steel, although other materials such as plastics may also be used. The frame members  44  should be made of a material which is relatively strong and yet is flexible to a sufficient degree to allow it to be coiled. The material should have a memory that allows the frame members to spring back to the expanded position when unfolded from the folded position. Thus, each frame member  44  is capable of assuming two positions or orientations, an open or expanded position such as shown in  FIG. 1A , or a folded position in which the frame member is collapsed into a size which is much smaller than its open position such as shown in  FIG. 3E .  
      Fabric or sheet material  46  extends across each panel  22 ,  24 ,  26 , and is held generally taut by the respective frame members  44  when in its open position. The term fabric is to be given its broadest meaning and should be made from strong, lightweight materials and may include woven fabrics, sheet fabrics or even films. The fabric should be water-resistant and durable to withstand the wear and tear associated with rough treatment by children. The frame members  44  may be merely retained within the respective frame retaining sleeves  42  without being connected thereto. Alternatively, the frame retaining sleeves  42  may be mechanically fastened, stitched, fused, or glued to the frame members  44  to retain them in position.  
      A hood  48  can be attached to the sides  34 ,  40  and  38  of the panels  22 ,  24  and  26 , respectively, to form a canopy or shade. The hood  48  can be made of the same material as the fabric  46 , and can be stitched to the sides  34 ,  40  and  38  of the panels  22 ,  24  and  26 , respectively, in the manner shown in  FIG. 1A . The lower edge  50  of the hood  48  can be positioned a distance from the bottom sides  36  of the panels  24  and  26  so as to provide an opening  60  (i.e., below the lower edge  50 ) for ingress and egress into the interior of the structure  20 . A mat  52  can have portions of two sides  54  and  56  permanently attached (e.g., stitched) or removably attached (e.g., such as shown in  FIGS. 2, 10A  and  11 ) to the bottom sides  36  of the panels  24  and  26 . The mat  52  can be a support that is made of the same structure and material as conventional sleeping bags, and provides a sleeping surface for the occupant of the structure  20 . For example, the mat  52  can be filled with a cushioning element that functions to provide a soft and cushioning support surface for the occupant&#39;s back and body. The cushioning element can include down, padding, or any other materials used to provide a soft and comfortable support for the user&#39;s back and body. The portions of the sides  54  and  56  of the mat  52  that are not attached to the panels  24  and  26  can be used in one of two manners. First, the unattached portions of the mat  52  can be folded up (see Arrow A 1 ) and then removably attached (e.g., via VELCRO™ pads  58 ) to the hood  48  to close the opening  60 , so that the structure  20  can be used as a tent. Second, the unattached portions of the mat  52  can be folded up (see Arrow A 1 ) and then inserted into the interior of the structure  20  to function as a blanket.  
      Thus, the panels  22 ,  24 ,  26  and the hood  48  define the interior of the structure  20 . The occupant can easily enter or leave the interior of the structure  20  via the opening  60 . The mat  52  functions as both a sleeping surface and as a cover to close the opening  60  when the occupant is sleeping inside the structure  20 . The mat  52  can even be used as both a sleeping surface and as a blanket to cover the user. The mat  52  can be conveniently and effectively attached in a removable manner to the hood  48 .  
       FIG. 2  illustrates a modification to the structure  20 , where the mat  52  is removably attached (e.g., via the use of VELCRO™ pads  64 ) to the panels  22 ,  24  and  26 . In addition, the hood  48  can be omitted in the modified structure in  FIG. 2  so that the outer edge  66  of the mat  52  can be removably attached (e.g., via the use of VELCRO™ pads  64 ) to the top side  34  of the panel  22 . As a result, the size of the opening  60  is increased, and a portion of the mat  52  would cover the entire opening  60 .  
      The structure  20  shown in  FIGS. 1A and 2  can be folded and collapsed very quickly and conveniently. First, as shown in  FIG. 3A , the mat  52  can be detached from the panels  22 ,  24 ,  26 , and the panels  24  and  26  are then folded about their hinged connections against the panel  22 . For the structure  20  in  FIG. 1A , the hood  48  can be folded in together with the panels  24  and  26  since the hood  48  is made of a flexible and foldable material. The mat  52  can be removed and folded separately (if the mat  52  is removably attached to the panels  22 ,  24 ,  26 ), or can be tucked against the panels  22 ,  24 ,  26  and folded together with the panels  22 ,  24 ,  26 . See  FIG. 3B . Then, in the second step shown in  FIG. 3C , the resulting structure is then twisted and folded to collapse the frame members and panels into a smaller shape. In particular, the opposite border  68  of the structure  20  is folded in to collapse the frame members with the panels. As shown in  FIG. 3D , the fourth step is to continue the collapsing so that the initial size of the structure is reduced.  FIG. 3E  shows the fifth step with the frame members and panels collapsed on each other to provide for a small essentially compact configuration having a plurality of concentric frame members and layers of the panels so that the collapsed structure has a size which is a fraction of the size of the initial structure.  
      To deploy the structure  20  for use, the user merely opens the folded panels  22 ,  24 ,  26 . The natural bias of the frame members  44  will cause the frame members  44  to uncoil, so that the panels  22 ,  24 ,  26  quickly spring back to the configuration shown in  FIG. 3A . The panels  24  and  26  are folded away from the panel  22 , so that the structure  20  is again ready for use. The mat  52  can be re-attached to the panels  22 ,  24 ,  26  (if the mat  52  is removably attached to the panels  22 ,  24 ,  26 ) or the mat  52  can be opened from the panels  22 ,  24 ,  26  and laid out flat. Thus, the structure  20  can be quickly and easily folded and collapsed for storage, and can be quickly and easily opened and re-deployed for use. The compact size of the collapsed structure  20  makes storage simple and convenient.  
       FIG. 4  illustrates another structure  80  having two panels  82  and  84  that are hingedly connected to each other along their top sides  86  thereof to form an inverted V-shape. Each panel  82  and  84  can have the same general construction as the panel  22  illustrated above, and include a frame member that supports and defines the shape of the panel  82  and  84 . Although  FIG. 4  illustrates each panel  82  and  84  as having four sides, including a top side  86 , a left side  88 , a right side  90  and a bottom side  92 , each panel  82  and  84  can be provided with any number of sides as desired. A mat  94 , which can have the same construction and material as the mat  52  described above, can be attached (either by stitching or removably attached via VELCRO™ pads) to the bottom side  92  of each panel  82  and  84 . Two opposing side walls  96 , which can be made entirely of fabric (as defined above), can be stitched or otherwise attached to the left and right sides  88  and  90  of the panels  82  and  84 . A slit  98  can be provided in one or both side walls  96  to allow for ingress and egress into the interior (which is defined by the panels  82 ,  84  and the side walls  96 ) of the structure  80 . In the structure  80 , the mat  94  functions as a base and as a sleeping surface.  
      The structure  80  can be conveniently folded and collapsed by folding the panels  82  and  84  towards each other about the hinged connection at the top sides  86 . The mat  96  can either be removed (if the mat  96  is removably attached) or folded between or outside of the panels  82  and  84 . The folding steps illustrated in  FIGS. 3C-3E  above can then be used to fold and collapse the structure  80  into a smaller configuration for convenient storage. The structure  80  can be quickly and easily re-deployed for use by opening the folded panels  82 ,  84  so that the natural bias of the frame members will cause the frame members to uncoil, causing the panels  82 ,  84  to quickly spring open. The panels  82  and  84  can be spread apart to the configuration shown in  FIG. 4 . The mat  84  can then be re-attached (if previously removed) or merely opened and laid out flat, and the structure  80  is ready for use again.  
       FIG. 5  illustrates another structure  120  that is similar to the structure  80 , but contains a few modifications. The structure  120  has a top panel  122  that has two opposing sides  124  and  126 , and two side panels  128  and  130  that are hingedly connected along their top sides  132  to the sides  124  and  126 , respectively, of the top panel  122 . Each panel  122 ,  128  and  130  can have the same general construction as the panel  22  illustrated above, and include a frame member that supports and defines the shape of each panel  122 ,  128  and  130 . Although  FIG. 5  illustrates each panel  122 ,  128  and  130  as having four sides, each panel  122 ,  128  and  130  can be provided with any number of sides as desired. A mat  134 , which can have the same construction and material as the mat  52  described above, can be attached (either by stitching or removably attached via VELCRO™ pads) to the bottom side  136  of each side panel  128  and  130 . One or two opposing end panels  138 , which can have the same general construction as the panel  22  illustrated above, can be hingedly connected to the left side  140  and right side  142  of the panels  128  and  130 . If only one end panel  138  is provided, the other end of the structure  120  can be covered by a fabric end wall that is stitched to the sides  140  and  142  of the side panels  128  and  130 , respectively. It is preferable to removably attach one side (e.g.,  146 ) of at least one end panel  138  to a side  140  or  142  of one side panel  128 ,  130  so that the end panel  138  can be swung open like a door to provide easier access to and from the interior of the structure  120 . The other side  148  of the end panel  138  can be stitched or removably attached to a side  140  or  142  of the other side panel  128 ,  130 . An opening  144  can also be provided in one or both end panels  138  to allow for ingress and egress into the interior (which is defined by the panels  122 ,  128 ,  130 ,  138 ) of the structure  120 . In the structure  120 , the mat  134  functions as a base and as a sleeping surface.  
      The structure  120  can be conveniently folded and collapsed in the following manner. For example, if the mat  134  is removably attached to one of the panels (e.g.,  130 ), the mat  134  can be detached from the bottom side  136  of the panel  130 , and the end panels  138  folded on top of the panel  128  about the hinged connection between the sides  140  or  142  (of panel  128 ) and the side  148  of the end panel  138 . Then, the panels  122  and  130  are folded on top of the panel  128  about the hinged connection between the sides  132  (of panel  128 ) and  124  in the direction of arrow A 2 . The panel  130  can then be folded on top of the panels  122  and  128  about the hinged connection between the sides  132  (of panel  130 ) and  126  in a direction opposite to that of arrow A 2  to form a stack of panels  130 ,  122 ,  128 ,  138  (in one possible order). The folding steps illustrated in  FIGS. 3C-3E  above can then be used to fold and collapse the structure  120  into a smaller configuration for convenient storage.  
      If the mat  134  is permanently attached to the panels  128 ,  130 , then the end panels  138  are folded into the interior of the structure  120  against the panel  128  (see direction A 4 ) about the hinged connection between the sides  140  or  142  (of panel  128 ) and the side  148  of the end panel  138 . Then, the panels  122  and  130  are folded on top of the panel  128  about the hinged connection between the sides  132  (of panel  128 ) and  124  in the direction of arrow A 2  to form a stack of panels  130 + 122 ,  128 ,  138  (in one possible order). The folding steps illustrated in  FIGS. 3C-3E  above can then be used to fold and collapse the structure  120  into a smaller configuration for convenient storage.  
      As an alternative, one or both of the hinged connections along the sides  124  or  126  can be a removable attachment, so that the panels  128  and  130  can be separated from the panel  122 . The three panels  122 ,  128 ,  130  can be placed on top of each other to form a stack of panels that can be folded and collapsed according to the steps illustrated in  FIGS. 3C-3E  above.  
      The structure  120  can be quickly and easily re-deployed for use by opening the folded panels  122 ,  128 ,  130 ,  138  so that the natural bias of the frame members will cause the frame members to uncoil, causing the panels  122 ,  128 ,  130 ,  138  to quickly spring open. The panels  122 ,  128 ,  130 ,  138  can then be opened or re-assembled to the configuration shown in  FIG. 5 . The mat  134  can be re-attached to the appropriate panels (e.g.,  128  and  130 ), and the structure  120  is ready for use again.  
       FIG. 6  illustrates a collapsible structure  160  that is made up of a single figure-eight frame member  162 . The structure  160  corresponds to the structure shown and described in U.S. Pat. No. 4,825,892, whose entire disclosure is hereby incorporated by this reference as though fully set forth herein. The figure-eight configuration of the frame member  162  is characterized by a left loop  164  separated from a right loop  166  by a crossover point  168 . The loops  164  and  166  have straight portions  170  and  172 , respectively, for resting on a flat surface when the structure  160  is in the configuration shown in  FIG. 6 . The frame member  162  can be formed from any of the materials used for the frame members  44  above. The figure-eight configuration shown in  FIG. 6  can be formed by a single 360 degree twist of the frame member  162 .  
      The structure  160  has left and right frame retaining sleeves  174  which retain the frame member  162 . The sleeves  174  also define straight portions to retain the straight portions  170  and  172 . Fabric  176  can be stitched or otherwise attached to the sleeves  174  to form opposing fabric side walls that are defined by the loops  164 ,  166 . In addition, fabric  178  can also be stitched to the sleeves  174  to form side walls that join opposing spaces between the loops  164 ,  166 . As a result, the fabric pieces  176  and  178  would define the interior of the structure  160 . A mat  180 , which can have the same construction and material as the mat  52  described above, can be attached (either by stitching or removably attached via VELCRO™ pads) to the straight portions  170  and  172 . An opening  182  can also be provided in one or both fabric pieces  176 ,  178  to allow for ingress and egress into the interior of the structure  160 . In the structure  160 , the mat  180  functions as a base and as a sleeping surface.  
      The structure  160  can be folded and collapsed by reference to  FIGS. 5-7  of U.S. Pat. No. 4,825,892. In summary, the straight portions  170 ,  172  are pushed towards each other, and the two loops  164 ,  166  are deformed so that they overlie each other and crossover  168  is partly bent towards one of the straight portions (e.g.,  170 ). The crossover  168  is then further bent towards the straight portion  170 , and then the steps in  FIGS. 3C-3E  hereinabove can be applied to complete the twisting and folding.  
       FIGS. 7A and 7B  illustrate a structure  200  which has two separate crossing frame members  202 ,  204  that can be of the same material as the frame member  44  illustrated above. The frame members  202 ,  204  cross at an apex  206 , and their respective ends are secured to holding mechanisms  208  provided at the corners of a mat  216 , so as to form a domed or apexed configuration for the structure  200 . Each holding mechanism  208  can take the form of an angled piece of fabric which retains the end of a frame member  202 ,  204  inside its interior. The mat  216  can have the same construction and material as the mat  52  described above. Fabric material  210  can be stitched or otherwise attached to the frame members  202 ,  204  to define the interior of an enclosing tent. Frame retaining sleeves  212  can be stitched to the fabric  210  to retain the frame members  202 ,  204 . An opening  214  can also be provided at one or more locations in the fabric material  210  to allow for ingress and egress into the interior of the structure  200 . In the structure  200 , the mat  216  functions as a base and as a sleeping surface.  
       FIG. 8  illustrates the same structure  200  from  FIG. 8 , except that the mat  216  is also used to cover the opening  214  using the same principles illustrated above in connection with  FIGS. 1A and 2 . In this regard, removable attachment mechanisms (such as VELCRO™ pads  218 ) can be used to removably attach portions of the mat  216  to the fabric material  210 . As an alternative, the covering (outer) portion of the mat  216  can be inserted through the opening  214  into the structure  200  for use as a blanket.  
       FIG. 9  illustrates a structure  20   a  that has the same general configuration as the structure  20  in  FIG. 1 , except that the panel  22  in structure  20  is now replaced by two overlapping panels  22   a  and  22   b . Otherwise, the other elements in structure  20   a  are the same as the corresponding elements in structure  20 . Therefore, the same numeral designations will be used in  FIGS. 1A and 9 , except than an “a” has been added to the designations in  FIG. 9 , and no further description of these elements will be repeated for structure  20   a  in  FIG. 9 .  
      The construction of the overlapping panels  22   b  and  22   b  is illustrated in greater detail in  FIGS. 1A and 3  of U.S. Pat. No. 5,975,101, whose entire disclosure is hereby incorporated by this reference as though fully set forth herein. In particular, each panel  22   a  and  22   b  is defined by a separate resilient frame member, so that the two separate frame members  260  and  262  together define the outer boundary of the overlapping panels  22   a ,  22   b , respectively. Each frame member  260 ,  262  can be the same as the frame member  44  in  FIG. 1B  hereinabove, and are fitted within each other, and overlap or cross-over each other at overlapping points  240  and  242 . The overlapping point  240  is defined by the intersection or crossing of the upper sides  244  and  246  of frame members  260  and  262 , respectively, and the overlapping point  242  is defined by the intersection or crossing of the lower sides  248  and  250  of frame members  260  and  262 , respectively. The overlapping points  240  and  242  can be positioned anywhere along the upper sides  244 ,  246  or lower sides  248 ,  250 . The two overlapping frame members  260 ,  262  are pivotable about their overlapping points  240  and  242  between two positions, a first completely open position in which both frame members  260 ,  262  lie flat in about the same plane (as shown in  FIG. 9 ), and a second folded position in which the frame members  260 ,  262  are folded towards each other (such as in the direction of arrow A 3  in  FIG. 10C ) to overlie each other. Each frame member  260 ,  262  is retained in a loop retaining portion (e.g., see  264 ) of one or more fabric pieces. For example, as shown in  FIG. 9 , two fabric pieces  254  and  256  are provided, one for each frame member  260  and  262 , respectively. Each fabric piece  254  and  256  covers (either partially or completely) and forms a panel  22   a  or  22   b  within the respective frame member  260  or  262 , and is preferably held in tension with the frame member  260  or  262 . The fabric pieces  254 ,  256  can also cross each other along an imaginary line defined by the two overlapping points  240  and  242 . The other details relating to the overlapping panels  22   a  and  22   b  are set forth in greater detail in the specification and drawings of U.S. Pat. No. 5,975,101, and shall not be repeated herein.  
      As illustrated in  FIG. 10A , the structure  20   a  can be provided with a separate fabric base  270  that has its edges stitched to the bottom sides  36   a ,  248  and  250  of the panels  22   a ,  22   b ,  24   a  and  26   a . The mat  52   a  can then be placed on top of and removably secured (e.g., by VELCRO™ pads  272 ) to the fabric base  270 .  
      As a further alternative,  FIG. 11  shows that the fabric base  270   b  can be provided in the form of a narrow strip of material that traverses the bottom sides  36   a ,  248 ,  250  of the panels  22   a ,  22   b ,  24   a  and  26   a , with VELCRO™ pads  272  provided along the fabric base  270   b . Otherwise, the structures shown in  FIGS. 10A and 11  are identical.  
       FIGS. 1A-10D  also illustrate how the structure  20   a  can be twisted and folded to reduce its configuration. In  FIGS. 10A and 10B , the mat  52   a  can be detached from the panels  22   a ,  22   b ,  24   a ,  26   a , and the panels  24   a  and  26   a  are then folded about their hinged connections with the panels  22   a  and  22   b , respectively, to be placed on top of the panels  22   a  and  22   b , respectively. Then, as shown in  FIG. 10C , the panels  22   a ,  22   b  are folded about the hinge defined by their overlapping points  240  and  242  to form one stack of panels  22   a ,  24   a ,  26   a ,  22   b  (in one possible order), as shown in  FIGS. 10D and 10E . The folding steps illustrated in  FIGS. 3C-3E  above can then be used to fold and collapse the stack of panels into a smaller configuration for convenient storage. If the mat  52   a  is not removably attached to the panels  22   a ,  22   b ,  24   a ,  26   a , the mat  52   a  can be folded against the stack of panels shown in  FIG. 10E , and folded along with the panels.  
      To re-deploy the structure  20   a  for use, the user merely opens the folded panels  22   a ,  22   b ,  24   a ,  26   a . The natural bias of the frame members  44  will cause the frame members  44  to uncoil, so that the panels  22   a ,  22   b ,  24   a ,  26   a  quickly spring back to the configuration shown in either  FIG. 10C  or  10 D. The panels  24   a  and  26   a  are folded away from the panels  22   a ,  22   b , and the mat  52   a  re-attached to the panels  22   a ,  22   b ,  24   a ,  26   a , or opened out and laid flat, so that the structure  20   a  is again ready for use.  
      While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.