Abstract:
A self supporting structure which may be used to support a platform such as a table top utilizes a plurality of elongated members and a ring. Each elongated member has one end resting on the floor on one point of a circumference, and the other end supporting the platform above the floor on a point substantially diametrically opposed. The elongated members cross each other proximate the center of the structure in a frictional and locking engagement maintained by the ring. That zone of convergence and the engagement of the elongated members between each other provide the only support for the structure which is self-supporting without extraneous means such as screw, glue or the like. The structure leave the floor below the edges and corners of the table top it supports free from interference with the legs of people seated at the table.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     Not Applicable 
     FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     SEQUENCE LISTING 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This relates to a collapsing supporting structure which can be used as a support for a platform such as a table. 
     2. Prior Art 
     The mobility of furniture, especially outdoor furniture, is often limited by the heaviness and the bulkiness in its construction. For example, some tables are difficult to move from one site to another without the aid of several persons, and transportation can leads to an alteration of the structure. In this regard, furniture which can be disassembled or folded possesses the advantage of being transported and stored easily. Many collapsible furniture designs have been proposed. In the U.S. Pat. No. 4,824,058 dated Apr. 25, 1989 and No. 5,074,502 dated Dec. 24, 1991, it is disclosed a table base structure comprising of elongated members extending angularly relative to each other, and connected between each other proximate the center of the base using a pair of slots included in elongated members. Stability and robustness of the structure are provided by the wideness of the elongated members, and by the large area the structure covers on the ground. Consequently this table base does not leave the floor below the edges and the corners of the table it support free from interference with the legs of the people sitting around. Other prior attempts have been made to provide supporting structure comprising of elongated members extending angularly with each other, useful for example, as a camera stand, a plant stand or the like, but are not applicable for holding with the require stability and robustness a dining table top. The U.S. Pat. No. 4,423,849 dated Jan. 3, 1984 discloses a self supporting structure utilizing three legs extending through a clinch plate including three holes of larger dimension than the legs and arranged in an equilateral triangle for the reception of the three legs. The three holes extend through the clinch plate at angles which direct the legs into a frictional and locking engagement with each other. 
     It does not appears that any prior art known to applicant have provided a detachable self supporting structure using a plurality of members extending in angular relation to each other, crossing each other proximate a center, held together in frictional and locking engagement, with a simple device such as a ring, and tilted from the floor at an angle small enough to leave the edges of the table top it supports free from interference with the legs of the people sitting around. In these respects, the supporting structure set according to the present application departs from conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of allowing the user to easily assembly and take apart the supporting structure suitable for a dining table top. 
     SUMMARY 
     A support structure utilizes a plurality of elongated members extending angularly relative to each other, and surrounded by a ring adjacent to the middle of the support structure. Corresponding ends of the elongated members rest on a supporting surface and the other ends of the elongated members may support a platform or a table top. 
     The form and size of the cross section of the elongated members are being determined in conjunction with the angle relative to each other, the size and shape of the ring, and the number of elongated members used in the support structure, as to force the elongated members into a frictional and interlocking engagement between each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of a self supporting structure. 
         FIG. 2  is a top plane view of the supporting structure shown in  FIG. 1 . 
         FIG. 3  is a side elevation view of the supporting structure shown in  FIG. 1 . 
         FIG. 4A  is an orthogonal sectional view of an elongated member taken at the sectional plane indicated by the section line  4 A- 4 A in  FIG. 3 . 
         FIG. 4B  is a horizontal sectional view of an elongated member taken at the sectional plane indicated by the section line  4 B- 4 B in  FIG. 3 . 
         FIG. 4C  is a sectional view of the supporting structure as seen in  FIG. 3 , taken at the sectional plane indicated by the section line  4 C- 4 C. 
         FIG. 5  is a portion of an elongated member illustrating the detail of a groove in which a segment of an external ring shown in  FIG. 4A  may be slotted in. 
         FIG. 6A  shows partial bottom plane view of the elongated members crossed proximate the center of the structure and together with an internal ring. 
         FIG. 6B  shows the recess in an elongated member in which an internal ring may be inserted. 
         FIG. 7A  is a perspective view of an embodiment of a supporting structure shown upside down, with attachment elements between each elongated members and the supported platform. 
         FIG. 7B  is a detailed view of the portion indicated by the dashed circle with the reference  7 B in  FIG. 7A   
         FIG. 7C  is a sectional view showing one end of an elongated member and its connection at the sectional plane indicated by the section line  7 C- 7 C in  FIG. 7A   
         FIG. 8  shows an embodiment of the supporting structure in the process of being locked with an external ring. 
         FIG. 9A ,  FIG. 9B  and  FIG. 9C  show the embodiment depicted in  FIGS. 7A   7 B and  7 C, with the elongated members being spread out. 
         FIG. 10A  is a perspective view of the second embodiment with the supporting structure spread and locked into its highest position. 
         FIG. 10B  is a cross-sectional view of the spreader and an elongated member. 
         FIG. 10C  is a perspective view of an embodiment with the supporting structure folded and locked into its lower position. 
         FIG. 11A ,  FIG. 11B  and  FIG. 11C  are respectively a top plane view, a front elevation and a side elevation of another embodiment of the supporting structure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following description, various aspects will be described, and various details set forth in order to provide a thorough understanding of the present invention. Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature or structure described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate of alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. 
     Referring more specifically to the drawings, as a whole, one embodiment of the self supporting structure is depicted by reference characters  20 A,  22 A,  24 A,  26 A,  28 A and  30  in the top plane view in  FIG. 2  and the side elevation view shown in  FIG. 3 . Elongated members  20 A,  22 A,  24 A,  26 A and  28 A extend at common angles relative to each other through an external ring  30 , and support a transparent table top  15 . In the top plane view shown in  FIG. 2  the reader can see that elongated members  20 A,  22 A,  24 A,  26 A, and  28 A are substantially identical. Thus, any description regarding elongated member  20 A also applies to elongated members  22 A,  24 A,  26 A and  28 A. A perspective view of the supporting structure is depicted in  FIG. 1 . 
     The side elevation view of the self supporting structure in  FIG. 3 , shows an orthogonal view of elongated member  20 A. It is to be noticed that the elongated members are not perpendicular, neither parallel between each other, therefore in  FIG. 3 , elongated members  22 A,  24 A,  26 A and  28 A are not seen in an orthogonal view. The elongated member  20 A comprises four sides which extend along an axis  25 . Side  36  terminates at the lower end at the intersection with a flat surface  21  resting on a supporting surface  17 , and at the intersection with a flat surface  23  substantially perpendicular to flat surface  21 . At the upper end, side  36  terminates at the intersection with a flat surface  22 , which is parallel to transparent table top  15 , and at the intersection with a flat surface  24  substantially perpendicular to flat surface  22 . Returning to  FIG. 2 , side  37  of elongated member  20 A is seen extending between side  36  and side  38 , along the axis  25 . Sides  35  (not shown in  FIG. 2 ) extended along axis  25  shown in  FIG. 3 , between sides  36  and  38  oppositely to side  37 . It should be noticed that a cushion  19  separates flat surface  22  from transparent table top  15 . 
     Elongated members extend from their upper end to their lower end and cross each other proximate the center of the self supporting structure through ring  30 . The tilt angle between the elongated members and platform  15 , is depicted by the reference character “T” seen at the upper left end of  FIG. 3 . 
     Although the term “ring” is used to describe the component  30 , it is contemplated that the shape of this component does not need to be circular and may include any shape including but not limited to rectangles, polygons, ovals, and the like. In some embodiments, the ring is made of brass, but it may be formed of any rigid material, including but not limited to, other metal, wood, and plastic. The ring may also be a closed loop of any non elastic flexible material such as a rope, cord, metal string, and the like. 
     Cross-sectional views of elongated members are shown in  FIGS. 4A ,  4 B and  4 C.  FIG. 4A  shows a sectional view of elongated member  20 A of  FIG. 2  taken at the sectioning plane orthogonally oriented relative to the axis  25  and in the direction indicated by section lines  4 A- 4 A. The cross-section view in  FIG. 4A  will be referred in the continuation of this description as the “orthogonal cross-section” of elongated members.  FIG. 4B  shows a sectional view of elongated member  20 A of  FIG. 3  taken at the sectional plane parallel to platform  15  and in the direction indicated by section lines  4 B- 4 B. The cross-section view in  FIG. 4B  will be referred in the continuation of this description as the “horizontal cross-section” of elongated members. 
       FIG. 4C  is a cross-sectional view of the assembled supporting structure taken at the sectioning plane parallel to platform  15 , and in the direction indicated by section lines  4 C- 4 C in  FIG. 3 .  FIG. 4C  shows a cross section of five elongated members together taken at the horizontal plane crossing the external ring  30 . This view defines a center point “C” of the assembled self supporting structure. 
     With reference again to  FIG. 4A , it may be observed that the orthogonal cross-section of elongated members describes the manufacturing cross-section. The four sides  36 ,  38 ,  35  and  37  extending along axis  25  seen in  FIG. 3  are depicted: the external side  36  also seen in  FIG. 3 , the internal side  38  positioned oppositely to side  36 , a left side  35 , and a right side  37 . Right side  37  is also seen also in the top plane view of the supporting structure depicted in  FIG. 2 . An angle “A” between left side  35  and right side  37  provides a trapezoidal shape to the elongated member cross-section. It is presently contemplated in a preferred embodiment that the four sides  35 - 38  extended along axis  25  of elongated member  20 A are flat surfaces and that elongated member cross section is trapezoidal. However, elongated member cross section may have different shapes as long as they can be pressed together by a ring or the like in a frictional and locking engagement. Elongated member cross section may not be uniform along axis  25  and may be rectangular, oval, circular, etc., or any other shape, as long as a frictional and locking engagement between elongated members is ensured inside ring  30 . Side  38  facing center “C” does not mechanically contribute to the robustness, stability and stiffness of the supporting structure, and can have any shape. It may be observed in  FIG. 4C  that all sides  36  of elongated members are in contact with ring  30 . Therefore, if ring  30  is made of a rigid material, the shape of side  36  proximate ring  30 , and the shape of ring  30  need to be define accordingly with each other. 
     In the purpose of making a complete disclosure, it is bring to the reader attention that in the preferred embodiments, there is a relation between the number “N” of elongated members used in the supporting structure which may be any number equal or greater than 3, the tilt angle “T” between elongated members and a supporting surface, and the angle “A” and “B” of the elongated members orthogonal and horizontal cross sections. 
     Angle “B” of the horizontal cross-section is only function of the number “N” of elongated members constituting the support structure, and is given in radian by the formula:
 
 B= 2 π/N.  
 
     To obtain the desired angle “B” when elongated members are tilted at angle “T”, the angle “A” of the orthogonal cross section needs to be determined, and may be provided in radian by the formula:
 
 A= 2×tan −1 [tan(π/ N )×cos(π/2 −T )].
 
     For example, to support with five elongated members a 60″ diameter circular platform at the height of 27″, a tilt angle “T” of 36° may be used. For the angle “B” to be equal to 360°/5=72°, elongated members may be manufactured with an angle “A” between left side  35  and right side  37  proximate to 46°. Elongated member length being measured along axis  25  between flat surface  21  and flat surface  22  may be proximate to 46″. 
     In some embodiments, elongated members  20 A,  22 A,  24 A,  26 A and  28 A may include a groove  31  as it may be seen in  FIG. 5 , showing a partial view of elongated member  20 A. Groove  31  is substantially parallel to flat surfaces  21  and  22  and may be positioned proximate the middle of elongated member length to set the position of ring  30  so that all portions of elongated members above and below ring  30  are the same when the self supporting structure is assembled. Groove  31  may have a V shape as it is depicted in  FIG. 5  but any other shapes in conjunction with the section of ring  30  may be used. 
     In some embodiments, a ring may be inserted in the elongated members instead of being around them, and still presses together the elongated members and ensures a frictional and locking engagement between each other.  FIG. 6A  is a partial bottom plane view of the structure showing elongated members left sides  35  and an internal ring  33  inserted inside recesses included in elongated members. A plane view of recesses when elongated members are tilted in operation may have the shape of a segment of a circle so that when elongated members are crossed, all recesses together form a complete circle. Ring  33  may be then placed into the circular recess formed by all individual recesses together.  FIG. 6B  is a partial orthogonal view of an elongated member in operation having the tilt angle “T” with the supporting surface, showing three sides and the recess  34 . Side  38  is the internal side facing the center “C” of the structure, and sides  35  and  37  are the left and the right sides having the angle “A” between each other as it is described in  FIG. 4A . Recess  34  extends on side  38 , substantially vertically from the intersection with side  35  to the intersection with side  37 , and extends horizontally as shown by the hidden lines in  FIG. 6B , forming an arc of a circle to end proximate the middle line of side  35 . 
     The supporting function of the structure is ensured by external ring  30  or internal ring  33  providing the frictional and locking engagement of the elongated members between each other. The weight of the table top  15  aids in the stability of the supporting structure. However, it should be noticed that external ring  30  or internal ring  33  is subjected to a tensile force exerted by the elongated members, and that the material it is made from needs to be chosen accordingly. External ring  30  or internal ring  33  may be a polygon having N sides, with N equal to the number of elongated members or may be a circle. 
     Any elongated members of the self supporting structure shown as a whole in  FIG. 1 ,  FIG. 2  and  FIG. 3  may be interchanged, and in the absence of cushions  19  may be turned upside down. It is to be noticed, that the number N of elongated members comprising the self supporting structure is not limited to five, and may be any number equal to or greater than three. 
     With reference from  FIG. 7A  to  FIG. 10C  an other embodiment of a supporting structure attached to a platform  16  is described.  FIG. 7A  is a perspective view of the structure shown upside down, to depict the attachment assemblies or attachments  40 ,  42 ,  44 ,  46  and  48 , connecting the elongated members  20 B,  22 B,  24 B,  26 B and  28 B, to the platform  16 . All elongated members as well as all attachments are substantially identical. Thus any description regarding elongated member  20 B also applies to elongated members  22 B,  24 B,  26 B and  28 B. Similarly, any description regarding attachment  40 ,  42 ,  44 ,  46  or  48  also applies to any others. It is to be noticed, that the number N of elongated members comprising the supporting structure is not limited to five, and may be any number equal to or greater than three. 
     The connection between elongated members and attachments is depicted in FIG.  7 B, 7 C. An enlarge perspective view of attachment assembly  44  and one end of elongated  24 B may be seen in  FIG. 7B  referenced to a dashed circle in  FIG. 7A .  FIG. 7C  shows a cross-sectional view of attachment  40  in  FIG. 7A , taken at the sectional plane and in the directions indicated by section lines  7 C- 7 C. Attachments comprise a base  41 , a right flange and a left flange,  43 R and  43 L, and a pivot  47 . Base  41  lies on one face, and is attached to the platform  16  in any suitable manner. Flanges  43 R and  43 L are vertically positioned and fastened on each side of the opposite face of base  41  and flush the edges of base  41 , so that the cross section of the three elements  41 ,  43 R and  43 L may form a “U” shape, indicated at  42  in  FIG. 7A  or at  44  in  FIG. 7B . Flanges  43 R and  43 L are parallel with a distance between each other at least equal to the distance between elongated member side  36  and elongated member side  38 . Elongated member side  36  faces the inner side of flange  43 L, and elongated member side  38  faces the inner side of flange  43 R. Two holes, one in each flange, extend along a common axis, and are substantially perpendicular to the flanges internal faces. A hole of a similar diameter extends through the elongated member proximate its end, and perpendicularly to side  36  and side  38 . A pivot  47  which may be made of a bolt and nut, a pin or the like, extends through the flanges holes and through the elongated member hole. Similarly to previous embodiments, elongated member side  36  terminates at the intersection with a flat surface  22  and at the intersection with a flat surface  24 . Elongated members are held by pivots  47 , flat surface  22  is substantially parallel to plate  41  and distant enough from plate  41  to avoid contact when elongated members rotates around pivot  47 . In operation, the user may remove or install the external ring  30  around elongated members as it is illustrated in  FIG. 8 . The ends of the elongated members attached to the platform are restrained from any movement except partial rotation around pivots  47 . Therefore, when ring  30  is sliding down, the opposite ends of elongated members spread out until a frictional and locking engagement occurs between elongated members inside ring  30 . Similarly, with internal ring  33 , the user crosses the elongated members until all elongated members right sides are in contact and form a common plane with the adjacent elongated member left side. All recesses  34  form a circle, and the internal ring  33  is then placed and pushed inside the recesses. 
     Turning to  FIGS. 9A ,  9 B and  9 C, the same embodiment is depicted with elongated members spread in an extension position. It may be observed on the cross-sectional view of  FIG. 9C  that elongated members rotation around pivot  47  is limited by the contact between flat surface  24  and base  41  of the attachment  40 . The position of pivot  47  in the attachment  40  is being determined in conjunction with the position of the hole of elongated member  20 B in respect with flat surface  24 , so that the maximal angle “T” between platform  16  and elongated members is substantially equal to 90° as illustrated in  FIG. 9A . 
     In spreading position, elongated members orientation being substantially vertical, the platform  16  may be elevated to a height approximately equal to elongated members total length.  FIG. 10A  is a perspective view of an embodiment of a supporting structure showing elongated members spread out and secured in extending position with a spreader  50 . Although spreader  50 , shown as an example in  FIG. 10A , has an circular shape with several segments, it is contemplated that the shape of this element does not need to be circular and may include various shapes including but not limited to polygons, disks, rays and the like. Spreader  50  may comprise an external face  51  shown in  FIG. 10A , an upper face  52  and a lower face  53  shown in the cross-sectional view in  FIG. 10B , taken at the sectional plane and in the directions indicated by section lines  10 B- 10 B. 
     Along external face  51 , the spreader circumference comprises several segments separated with steps. Between steps, the radius of the segment measured along the external face  51  varies from a small radius to a large radius. As seen in  FIG. 10B , elongated member  24 B includes a slot  55  which comprises a wall portion  56 , and a floor portion  57 . Wall portion  56  and floor portion  57  are depicted as being flat and extending from side  36  and opposite side  38 . In  FIG. 10A , side  36  is shown on elongated member  20 B, and side  38  is shown on elongated member  24 B. Thus the transverse distance along wall  56  is at least equal to the thickness along external face  51  of spreader  50 . In operation, elongated members are spread with flat surfaces  24  in contact with plates  41 , and the user may position the spreader inside the structure with the smaller radius of each segment facing the slot  55  of each elongated member, and rotates the spreader until segment sides  51  and walls  56  contact each other. In the cross-sectional view in  FIG. 10B , the relative amount of clearance between spreader segment side  51  and slot wall  56  is exaggerated for the purposes of illustration. 
     At this point of the description, it may be obvious that in this embodiment set forth, the supporting structure may be used alternatively with a ring or with a spreader, and that platform  16  may be risen at two different heights. Turning to  FIG. 10C , the supporting structure is shown with elongated members in crossing position locked with internal ring  33  (not shown), and platform rises at the lowest height. 
     For example, the same structure comprising five elongated members may support a platform at a height proximate  19 ″ (coffee table top height) with elongated members in crossing position, and at a height proximate to 39″ (pub table top height) with elongated members in extended position. In  FIGS. 3 and 4A , the manufacturing angle “A” between elongated members left side  35  and right side  37  may be equal to 40°, the tilt angle “T” of elongated members in crossing position may be equal to 30°, and elongated member length being measured along axis  25  between flat surface  21  and flat surface  22  may be equal to 39″. 
     Turning now to  FIG. 11A ,  FIG. 11B  and  FIG. 11C , an embodiment is shown in which two different pairs of elongated members are used to support an oblong platform. The top plane view of the supporting structure is shown in  FIG. 11A . Two long elongated members  62  and  64  support the platform  18  along its length, and are shown in a side elevation view depicted in  FIG. 11B  with a straight axis and a tilt angle “T”. Two short elongated members  66  and  68  support the platform  18  along its width, and are shown in a side elevation view depicted in  FIG. 11C  with a curved axis. A ring  70  having a rectangular circumference surrounds the elongated members  62 ,  64 ,  66  and  68  proximate half the height of platform  18 . It may be obvious that side elevation views in  FIGS. 11B ,  11 C are 90° from each other. Although the axes of long elongated members  62  and  64  are shown straight, it is contemplated that they may be curved in any direction above and below ring  70 . Similarly, axis of short elongated members  66  and  68  shown curved in  FIG. 11C  may be straight or curved in any direction below and above ring  70 . Referring again to  FIGS. 4A ,  4 B showing horizontal and orthogonal cross-sectional views of elongated members in previous embodiments, the same concept is applied here to determine the angles “A” and “B”, in conjunction with the tilt angle “T” and the number of elongated members. It should be understood that proximate ring  70 , angle “A” of the orthogonal cross section, angle “B” of the horizontal cross section, and tilt angle “T” of the two pairs of elongated members need to be substantially identical to ensure a frictional and locking engagement of the elongated members inside ring  70 . 
     While certain exemplary embodiments have been described and shown in the accompanying drawings for the purpose of making a complete disclosure of the current invention, it is to be understood that such embodiments are merely illustrative and not restrictive. It will become apparent to those skilled in the art that modifications and changes are possible without departure from the scope and spirit of the invention. It is intended that the following claims be interpreted to embrace all such modifications.