Abstract:
Components of and method for making a frame member framework having panel recesses accepting structural panels in a plane tangent to the exterior of the frame member. The tubes and fittings allow easy assembly of large structures. The panels secured within the panel recesses bear loads imposed on the structure and minimize torque at the fittings. The finished structure is streamlined, with flush junctions of all components. Alternative embodiments include panel recesses in angular or channeled shapes which act to secure the panels to the framework, and other panel securing attachment which are externally invisible on the completed structure. Panel securing means include screws, bolts, studs, pins, adhesives, welding and equivalents. End fittings are secured to frame members by any common and known ways. Frame members, fittings and panels may be made of any of a wide range of materials including metals, alloys, plastics, rubbers, wood, and composites. The panel recesses may engage the entire periphery of the panels, by traversing from frame member to fitting around the entire periphery of the panel.

Description:
RELATED APPLICATIONS 
     This application is a Continuation-In-Part of U.S. application Ser. No. 09/442,327, filed Nov. 17, 1999 now U.S. Pat. No. 6,481,918. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to components for easy construction of structures, and more particularly to tubular frame components for easy construction of strong, externally smooth structures 
     2. Discussion of the Background 
     It has long been known that combinations of tubes and connectors can be used to quickly create framework structures such as jungle-gyms and tents. By connecting tubes at their ends, the frameworks for geodesic domes, furniture and display cases can be created. 
     In a typical system, that of U.S. Pat. No. 5,169,258 (issued to Raynak), the fittings have cylindrical pins protruding from a semi-spherical body. PVC pipes are plugged onto the pins and so used to form even large structures such as the framework of a house. Other similar patents (U.S. Pat. No. 4,273,462 to Fukuchi; U.S. Pat. No. 4,242,969 to Checkwood et al.; U.S. Pat. No. 4,187,649 to Chaffee; U.S. Pat. No. 3,074,203 to Paksy) use various types of connectors to assemble pipes into larger structures such as display cases and coffee tables. 
     Other patents have used the same general technique with tubes having a square cross section: U.S. Pat. No. 5,820,289 to Kern et al.; U.S. Pat. No. 5,451,115 to Sayres; U.S. Pat. No. 4,368,998 to Pestoor; and U.S. Pat. No. 3,736,035 to Brown et al. There are certain advantages all such systems possess. 
     All the references listed above combine flexibility of design with ease of construction. By altering the arrangement of connectors and tubes new structures can be designed with great ease. Construction is also very easy, as the standardized connectors (also called fittings, joints or corners) and tubes (also called pipes or frame members) can be manufactured with great economy and put together quickly, with few or no special tools and by personnel having little experience or training. If the structure needs to be later modified, most such designs allow for easy disassembly and reassembly in a new configuration. 
     Such structures also tend to have certain general weaknesses. The completed structure is not a shell or panel type of structure and therefore stress, strain, and torsion, are all applied directly and fully at the couplings between fittings and pipes. Repeated cycles of use, or repeated applications of force to the completed structure, quickly deform the couplings and the structure tends to fall apart shortly. 
     Most of the references cited above do not refer to paneling. Those that do refer to paneling or shelves (for example, Brown and Kern) teach the panel or shelf as something requiring support from the tubular cross members. None of the references offer means for reducing the forces induced in the couplings, and none offer the panels as structural support for the framework. Finally, none of the references disclose structure allowing a flush, smooth tangential connection of paneling and circular section framework. In each case, paneling is taught as being radial to the tubular framework, not tangential. 
     One attempt to make the panels bear a structural burden can be seen in U.S. Pat. No. 5,647,650, issued Jul. 15, 1997 to Daugherty et al. In this case, the tubular support structures (there are no cross beams) have wide flanges which grip the end of a wall, thus helping to distribute imposed forces. The panels may be angled, rather than directly radial, but the wide flanges necessarily protrude from the completed structure. More importantly, that system is not actually modular, as it lacks fittings or connectors to connect the tubes, thus flexible design and assembly in to a wide variety of structures is not possible. The modular tubes of Daugherty (&#39;650) are vertical members only, held in place on a base plate which may form the bottom of a wheeled cabinet. A complete framework, as such, is not present, and as with the above references, no structure is disclosed allowing a smooth, flush tangential connection of the paneling and the framework. 
     SUMMARY OF THE INVENTION 
     The invention consists of several components which interlock to form a strong, externally smooth structure. Tubes, rods or frame members are connected at their ends by fittings (also called joints or corners). Alternatively ends and fitting joints are part of the rod or frame member and attach to other ends or fitting of cross members. The fittings have faces which are symmetrical in external form and size the external surface of the tubes, rods or frame members, thus providing flush, smooth joints. The invention also has a panel which attaches to the framework. The panel connects to the side of the framework, on the plane defined by tangents of the tubes, rods or frame member rather than in the plane defined by the center axes of the tubes, or members, or some plane in between. 
     In order to provide a smooth, flush fit between the panel and the framework, a recess is provided in the frame member and fittings to accept the panel. The recess runs in a continuous groove along the length of a frame member along the matching faces of the fitting or ends, and then along the length of a second frame member matched to its end of the fitting. The recesses may engage the entire periphery of the panels, by traversing from tube to fitting around the entire periphery of the panel. They may also be discontinuous. 
     The recess forms a partial chordal section of the frame member if one were to view a circular cross section of a tube: one surface of the panel fits chordally into the tube&#39;s surface while an edge of the panel is substantially radial to the tube. In other embodiments the tangent chord is formed by the panel coming from the curved outer surface of the frame member, making a smooth transition from the panel to the frame member. Thus the recess has a first surface which is parallel to the panel&#39;s exterior surface, which will be referred to herein as the bottom of the recess. The recess also has one surface which is substantially normal to the panel&#39;s exterior surface, which will be referred to herein as the peripheral wall of the recess. The thickness of the panel is equal in depth to the recess as measured from the exterior surface of the tube or member to the bottom along the peripheral wall. The panel&#39;s exterior surface will thereby join smoothly to the member&#39;s exterior surface, and to the exterior surfaces of the fittings, without any step, gap, or discontinuity. 
     The fasteners used to hold the various components together may be disposed within the completed structure, resulting in an entirely smooth exterior. This requires that three different properties of the edge of the panel be shaped to exactly mate with the recess. First, the edge outline is the shape of the panel in two dimensions not including thickness. The edge outline may be a perfect square, a square with rounded corners, or other shapes. Also, the panel may not be wholly planar, instead being contoured in three dimensions, for example as a nose-cone or other bulbous shape. 
     The second property, the edge thickness, is generally equal to the depth of the recess. However, edge thickness may be less than the depth of the recess if, for example, the peripheral wall is situated at an angle to the radius of the tube, rather than being exactly radial. The balance of the panel is also usually, but not necessarily, the same thickness as the edge thickness. 
     Finally, the edge cross section is viewed in the plane normal to the surface of the panel and perpendicular to the axis of the tube. The shape of the edge cross section may either vary or be constant around the entire periphery of the panel. In one embodiment, the edge cross section will be complementary to the cross section of the recess in the plane perpendicular to the axis of the tube. The complementary edge cross section and recess cross section provide a snug and continuous contact between the panel edge and the recess. The three different properties of the edge of the panel thereby create the three dimensional shape exactly matching the space defined by the recess. 
     Smooth exteriors are beneficial in applications in which streamlining is important, such as trailers, or where cleanliness is important. Smooth exteriors are also useful any time projections on a structure would be disadvantageous, for example when projections might catch on external machinery. The form is also eye-pleasing. 
     The structure&#39;s interior will not be smooth or flush; because the panels are tangential to the exterior of the frame member, a cavity between the panel and the fittings and tubes of the framework is formed in the interior. There may also be visible on the inside of the structure, apparatus for securing the panels to the framework. For example a linear bead of welded metal may be used to secure the panel to the tubes and fittings. Stud/bolt and bracket combinations may also be used. This less eye-pleasing interior can be easily modified by making a structure with panels tangential to both sides of the framework. This embodiment not only allows both the structure&#39;s interior and exterior to be smooth, but also greatly strengthens the structure. The interior of the assembled structure should not be confused with the “tube interior,” the interior of any tube components. 
     More importantly, the panel is a planar load bearing member. Most fitting and tube structures must absorb all imposed forces at the connection of cross pieces and corner, thereby allowing small forces to generate large torques. In contrast, the present invention takes advantage of the panel to provide a distributed load bearing structure: a monocoque shell. A load imposed on a frame member at the top of the structure will not be primarily transmitted to the fittings at the end of the frame member, but rather largely to the panel edge by the opposing peripheral wall of the tube&#39;s recess. The panel will in turn transmit the force to the recess of the tube on its far side, and so on until the force is absorbed. 
     It is therefore one object of the invention to provide an improved structural system allowing use of structural panels with easy assembly. 
     It is another object of the invention to provide a frame member and fitting framework which allows speedy assembly, yet which reduces the forces induced in the couplings between tubes and fittings. 
     It is another object of the invention to provide a structural system which allows easy assembly of a strong monocoque structure. 
     It is another object of the invention to provide a structural system allowing easy assembly of strong structures able to withstand numerous cycles of use. 
     It is another object of the invention to provide a structural system allowing use of structural panels yet allowing easy manufacture of the system components. 
     It is yet another object of the invention to provide a structural system allowing a smooth, flush joint between panels and elements of a tubular framework. 
     It is yet another object of the invention to provide a structural system allowing easy assembly of strong, streamlined structures. 
     It is yet another object of the invention of provide a structural system allowing a tangential joint between panels and elements of a framework. 
     It is yet another object of the invention to provide a method of constructing a frame member and fitting structure having structural panels and a smooth exterior. 
     It is yet another object of the invention to provide a structural system allowing construction of a structure which has no projecting flanges, fittings, or fasteners. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 a  is a cross sectional view of a tube, in a plane perpendicular to its axis, according to the preferred embodiment of the invention. 
     FIG. 1 b  is a perspective view of a tube according to the preferred embodiment of the invention. 
     FIG. 1 c  is a perspective view of a tube mated to a panel according to the preferred embodiment of the invention. 
     FIG. 2 a  is a cross sectional view of a tube, in a plane perpendicular to its axis, according to a first alternative embodiment of the invention. 
     FIG. 2 b  is a perspective view of a tube according to the preferred embodiment of the invention. 
     FIG. 3 a  is a perspective view of an elbow-type fitting according to the preferred embodiment of the invention. 
     FIG. 3 b  is a perspective view of a mated fitting and tube according to the preferred embodiment of the invention. 
     FIG. 4 is a perspective view of a T-type fitting according to the preferred embodiment of the invention. 
     FIG. 5 a  is a cross sectional view of a tube, in a plane perpendicular to its axis, according to a second alternative embodiment of the invention. 
     FIG. 5 b  is a perspective view of a tube according to a second alternative embodiment of the invention. 
     FIG. 6 a  is a cross sectional view of a tube, in a plane perpendicular to its axis, according to a third alternative embodiment of the invention. 
     FIG. 6 b  is a perspective view of a tube according to a third alternative embodiment of the invention. 
     FIG. 7 a  is a cross sectional view of a tube, in a plane perpendicular to the tube axis, according to a fourth alternative embodiment of the invention. 
     FIG. 7 b  is a perspective view of a tube according to a fourth alternative embodiment of the invention. 
     FIG. 8 a  is a cross sectional view of a tube mated to a panel, in a plane perpendicular to the tube axis, according to a fifth alternative embodiment of the invention. 
     FIG. 8 b  is a perspective view of a tube mated to a panel according to a fifth alternative embodiment of the invention. 
     FIG. 9 a  is a cross sectional view of a tube mated to a panel, in a plane perpendicular to the tube axis, according to a sixth alternative embodiment of the invention. 
     FIG. 9 b  is a perspective view of a tube mated to a panel according to a sixth alternative embodiment of the invention. 
     FIG. 10 is a perspective view of a structure constructed with the components and according to the methods of the invention. 
     FIG. 11 represents another embodiment of the frame member with the end connectors integral to the side. 
     FIG. 12 represents the assembly of two similar frame members, and two cross members to form a complete frame into which panels would be inserted to complete the side or sides of the structure. 
     FIG. 13 represents an end view of one example of a frame member illustrating its exterior form with recesses for the panels on two sides and the interior surface being concave. 
     FIG. 14 represents a frame member without the end fittings for eomers, this would be a cross member. 
     FIG. 15 represents an end view of an example of a cross member showing its interior flat surfaces and the recesses for panels. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention can be better understood by examination of the attached drawings. 
     FIG. 1 a  is a cross sectional view of one embodiment using a frame member or tube  100 , in a plane perpendicular to its axis, according to this embodiment of the invention. FIG. 1 b  is a perspective view of a section of the tubel 00 . Tube  100  is depicted to be circular, however, other cross sections, such as ellipses, ovals, or polygonal figures are all possible without departing from the essence of the invention. Tube  100  is pictured to be hollow, but it is obvious to use a solid member, or one having more complex internal structure. Tube  100  has an exterior surface  102  which defines the circumference of the tube  100 . Exterior surface  102  is interrupted by peripheral wall  104  which cuts into the tube  100 . Peripheral wall  104  and bottom  106  together define the outline and cross section of recess  108 . 
     The cross section of tube  100  with recess  108 , in a plane perpendicular to the axis of tube  100 , may be described as the intersection of two partial chords of tube  100 . In this case, neither bottom  106 , nor peripheral wall  104  cut completely across tube  100  from one point on its circumference to another. As the partial chord defined by the peripheral wall  104  is radial, within the cross sectional plane, the recess  108  is only a fraction of the section which would be defined by two radii meeting the circumference of the tube  100  at the same locations as the partial chords defined by bottom  106  and peripheral wall  108 . This section defined by recess  108  will be referenced herein as a partial chordal section. 
     Note too that bottom  106  necessarily has the geometric property of being parallel to some tangent of the circumference of tube  100 . The points at which a tangent is parallel to a chord on a circular surface are those points which are directly perpendicular to the median of the total chord length. Tangents may be at other points on bodies or surfaces of other shapes. Bottom  106  may have projections, studs, or different depths at different portions of panel recess  108  and thus need not be entirely uni-planar; however, bottom  106  is uni-planar in the preferred embodiment shown. 
     In this embodiment, peripheral wall  104  is radial to the axis of tube  100  and is located at the median of a chord formed by projecting the partial chord defined by bottom  106  across the tube  100  to the opposite point on the exterior surface  102  of the tube  100 . Thus peripheral wall  104  meets exterior surface  102  at the point on the circumference of tube  100  at which the partial chord defined by bottom  106  is parallel to the tangent to the circumference of the exterior surface  102  of the tube  100 . 
     The result of this is that a flat body such as a panel  110  in FIG. 1 c  placed along the length of tube  100  will sit with its edge in recess  108 . Further, if the panel  110  has a thickness equal to the radial depth of recess  108 , measured from the tangent point where peripheral wall  104  meets exterior surface  102  to the bottom  106  or its chordal projection, the exterior surface of the panel  110  will meet exterior surface  102  of tube  100  at a smooth junction. In this preferred embodiment of the invention, the radial depth of recess  108  is equal to the length of height of peripheral wall  104 . 
     The cross section of FIG. 1 a  can also be visualized as an end view of the tube  100 . Tube  100  may have one or more ends for connection with other components. Tube  100  may branch and form any one of many complex shapes, for example a “T” having three ends. The end of tube  100  is generally annular in shape, with a notch in the outline corresponding to the recess  108  in the exterior surface  102 . 
     Panel recess  108  will generally be straight. While panel recess  108  may run the entire length of tube  100 , as in the preferred embodiment, this is not necessary. In one equivalent obvious to those skilled in the art, panel recess  108  may span only a fraction of the length of the tube  100  to seat a flat body of length shorter than that of the tube  100  within recess  108 . Panel recess  108  may also be considered to be an asymmetrical groove on exterior surface  102 . 
     Tube  100  is only one component of the structural kit of the invention. Such a structural kit could contain any of a wide range and number of components including tube  100 , panels  110 , fittings  300  (see FIG. 3 a ), and special modifications of these. The structural kit may be organized so as to provide easy assembly of a predetermined structure, with all tubes  100 , panels  110 , and fittings  300  necessary to the task, as well as fasteners, special parts, and so on. One such kit may be used to make a storage box, a second kit having different components may be used to build a storage shed, and a third kit may be used construct a trailer. Many additional possibilities are obvious. 
     The tube or frame member  100  may be constructed in many ways, and composed of a wide range of materials. Tube  100  may be extruded, machined, milled, rolled, or constructed by any other method. For example, the construction of a square tube out of four strips of material is obvious to those skilled in the art. Recess  108  also may be created as tube  100  is extruded, machined, etc, or, recess  108  may be created after tube  100  is finished, by machining, etching, or other finishing process. Tube  100  may be constructed of any of a wide range of materials, including but not limited to, metal, metal alloys, wood, plastic, rubber, other polymers, composites and so on. Tube  100  may be any length or diameter. 
     FIG. 2 a  is a cross sectional view of tube  200 , in a plane perpendicular to its axis, according to a first alternative embodiment of the invention. FIG. 2 b  is a perspective view of tube  200  according to this alternative embodiment. Tube  200  has first recess  202  and second recess  204 . Recess  202  and recess  204  are depicted to be at an angle of 90 degrees to each other, in an orientation allowing flat bodies nestled within them to be perpendicular to each other. This is not necessary—an angular alignment of greater or less than 90 degrees may be desirable for the finished structure. It is even possible to conceive of structures requiring recess  202  and recess  204  be parallel or co-planar. 
     The invention may also have components with greater or lesser numbers of panel recesses. One member of the structural kit of the invention may have no panel recesses, another member may have more than two. 
     FIG. 3 a  is a view of a fitting  300  according to the preferred embodiment of the invention. Fitting  300  has a first connector  304  projecting from a first annular face  306  and a second connector  316  projecting from a second annular face  312 . FIG. 3 b  is a perspective view of fitting  300  mated with tube  302  wherein second annular face  312  abuts tube end  314 . Annular face  312  and tube  314  are axially aligned. The cross section of annular face  312 , in the plane perpendicular to this axis of alignment, is symmetrical to the cross section, in the same plane, of tube end  314 . 
     Projecting from fitting  300  into tube  302  is connector  316 , unseen in FIG. 3 b . The shape of fitting  300  is semi-cylindrical. Fitting  300  has a smooth exterior resembling several intersecting tubes of the same diameter as tube  302 . When tube  302  is connected to fitting  300 , the joint is smooth, the tubular shape of tube  302  carrying across the joint to fitting  300 . In the preferred embodiment of the invention, connector  304  and connector  316  are cylindrical. Tube  302  has an unseen tubular interior of the same diameter as the connector  316 . Tube  302  fits snugly over the connector  316 , providing a tight mating. 
     Fitting  300  and tube  302  are angularly aligned. Tube  302  has recess  310 . Matching recess  310 , fitting  300  has panel recess  308 . When tube  302  is mated to fitting  300  and recess  308  is properly aligned with recess  310 , the two merge into a single larger recess. The recesses  308  and  310  on fitting  300  and tube  302 , respectively, may be alternately disposed along the exterior of the angle formed by the fitting  300  and tube  302 , creating an interior corner for defining an aperture in a paneled surface, such as a window. 
     Recess  308  may have a cross section, generally viewed in the plane perpendicular to the axis of the circumference of fitting  300  at any particular point, which varies in order to accommodate a flat surface matching recess  310  to the variable contours of fitting  300 . However, the cross section of recess  308  will match that of recess  310  at annular face  312 . Thereafter, the variations in cross section of recess  308  may change to maintain the desired surface across the contours of fitting  300  to accommodate a panel. 
     Connector  304 , (which may be referred to as a connector, locator, guide, fastener, or by other terms) may be any of a wide range of mechanisms. In the preferred embodiment, it is a cylindrical body which frictionally engages the interior of tube  302  to provide a secure connection. However, connector  304  may be an adhesive, or a cylindrical body covered with adhesive, or any of the ingenious connectors found in the reference patents cited earlier and incorporated herein, or any of many obvious equivalents, all without departing from the scope of the invention. 
     Cylindrical connector  304  may be a solid projection from fitting  302 , or it may be detachable. It may be rubber covered, or have circular or spiral flanges around the perimeter, to create a tighter joint or a pressure resistant seal. Connector  304  may also be equipped with a washer or O-ring, having a plan-form identical to annular face  306 . 
     Fitting  300  is depicted with two annular faces,  306  and  312 , and two connectors,  304  and  316 , of the same size. However fitting  300  may also serve to connect tubes or other components of different diameters or even different cross sectional shapes. In addition, the invention contemplates the creation of structures having a smooth exterior, but the interior may be quite complex. Thus, annular face  306  might be symmetrical to the tube end  314  which mates to it, only in those regions which will be externally visible in the finished product. This is one obvious equivalent embodiment of the invention. 
     Although not preferred, recesses  308  and  310 , in fitting  300  and tube  302 , respectively, may be disposed such that a panel resting in recesses  308  and  310  is not tangential to the exterior surfaces of the fitting  300  and tube  302 . The exterior surface of a structure in such an embodiment may not be externally smooth. Fitting  300  may be manufactured by any of the methods mentioned earlier in reference to tube  100 , and may be made of any of the same materials. Fittings, tubes and panels need not necessarily all be of the same materials. 
     FIG. 4 is a perspective view of a T-type fitting  400 . Fitting  400  is designed to accommodate three tubes (not pictured) in a planar array. Thus fitting  400  has three connectors,  402 ,  404 , and  406 , and two panel recesses,  408  and  410 . Fitting  400  might also have sufficient connectors and annular faces, in other embodiments, to accommodate almost any number of tubes, in planar or non-planar array. In particular, fitting  400  may have three orthogonal connectors and thus serve as a corner of a three dimensional structure. The corner need not be entirely composed of right angles, it may also include any desired angle, allowing for example streamlining of a trailer or for other reasons of convenience. The fitting  400  may also have more than three couplings. 
     FIG. 5 a  is a cross sectional view of tube  500 , in a plane perpendicular to its axis, according to a second alternative embodiment of the invention. FIG. 5 b  is a perspective view of tube  500  according this second embodiment. Tube  500  has exterior surface  502 ; peripheral wall  504 , channel  506 , and bottom  508  form recess  510 . In this second embodiment of the invention, the panel (not shown) has at least one protrusion, a tab or flange, along the panel edge which engages channel  506 . The panel is secured within recess  510  by the construct of channel  506 . 
     FIG. 6 a  is a cross sectional view of tube  600 , in a plane perpendicular to its axis, according to a third alternative embodiment of the invention. FIG. 6 b  is a perspective view of tube  600  according this third embodiment. Tube  600  has exterior surface  602 ; peripheral wall  604  and bottom  606  define recess  608 . In this third alternative embodiment of the invention, peripheral wall  604  is not radial to tube  600 ; rather, peripheral wall  604  and bottom  606  meet at an acute angle. Peripheral wall  604  and exterior surface  602  do, however, still meet at the point on exterior surface  602  radially outward from the median point of a chord projected by the bottom  606 . As a result, the panel (not shown) still meets exterior surface  602  at an exact tangent. A complimentary panel has a cross section corresponding to the cross section of panel recess  608  with an acute angle on its edge allowing the panel to mate with and be secured within panel recess  608 . 
     FIG. 7 a  is a cross sectional view of tube  700 , in a plane perpendicular to its axis, according to a fourth alternative embodiment of the invention. FIG. 7 b  is a perspective view of tube  700  according this fourth embodiment. Tube  700  has exterior surface  702 ; peripheral wall  704  and bottom  706  form recess  708 . Tube  700  may be made of any thickness desired, or may be solid, or may be solid for most of its length but have hollows at each end to receive fitting connectors (not shown). 
     A panel (not shown) is secured to tube  700  by the action of pins  710 , which interpenetrate both the panel and peripheral wall  704 . Peripheral wall  740  and the panel may have cavities prepared for pins  710 , or the pins  710  may be driven into each, respectively. Pins  710  may be manufactured separately, or as part of tube  700 , or as part of the panel. Pins  710  may also be replaced by dados in peripheral wall  704  and the panel with connecting biscuits. 
     Instead or in addition to the peripheral wall  704 , bottom  706  may be similarly varied as shown in FIGS. 5 a - 7   b ; i.e., bottom  706  may have pins, channels, studs, or other indentations or projections. Bottom  706  may also vary in depth (as measured from the intersection of the peripheral wall  704  and the exterior surface  702 ) over its longitudinal direction if the panel is varied in thickness to match. 
     FIG. 8 a  is a cross sectional view of tube  800  mated to panel  806 , in a plane perpendicular to the axis of tube  800 , according to a fifth alternative embodiment of the invention. FIG. 8 b  is a perspective view of tube  800  mated to panel  806  according this fifth embodiment. Panel  806  abuts both peripheral wall  802 , which mirrors the edge outline and thickness of panel  806 , and bottom  804 . In this fifth alternative embodiment of the invention, panel  806  is secured to tube  800  by a bead of welding  808  at their interior junction. While the bead of welding  808  may be located on the exterior junction, that embodiment somewhat mars the smoothness of the finished structure. Bead of welding  808  may be a normal longitudinal line or discontinuous as with spot welds. 
     FIG. 9 a  is a cross sectional view of tube  900  mated with panel  906 , in a plane perpendicular to the axis of tube  900 , according to a sixth alternative embodiment of the invention. FIG. 9 b  is a perspective view of tube  900  mated with panel  906  according this sixth embodiment. This embodiment provides a more secure attachment of panel  906  to tube  900 . Peripheral wall  902  and bottom  904  still hold panel  906  in a load bearing relationship, but the attachment is carried out elsewhere. Tube  900  has bracket  908 , with an aperture  914  therein. Panel  906  has stud  910  which projects from panel  906 , through bracket  908 , and is secured therein. Bracket  908  may be equipped with a grommet (not shown) for better connection. In one alternative embodiment of the invention, stud  910  may be a screw or a bolt secured with a nut  912 . 
     In another alternative embodiment, bracket  908  is omitted, and a screw penetrates panel  910  and tube  900  through bottom  904  to secure them together. The screw head may be recessed, to retain streamlining of the exterior of the completed structure. Such a fastening method is shown in FIG. 10, which depicts a structure  1000  utilizing the components and methods disclosed herein. Structure  1000  is shown without a top panel so that the recess  1006  is visible. Panels  1008  are attached to the tubes  1002  and fittings  1004  with screws  1010 . Many other variations of attachment apparatus and fastening methods will be obvious to those skilled in the art. 
     The embodiment illustrated in FIG. 11 is a frame member  1100  with two corner connectors  1102  are attached or are integral to one frame member or side piece. One or two corner connections and one side piece may be made in one unit. It can also include a side and one corner connector as a single piece. 
     In FIG. 11 it is shown as a single piece with the corner connections all as one unit. The exterior surface  1104  of the frame member is rounded as in the other embodiment where it is the external surface of a rod or a tube like structure, to have a smooth surface from side panel around the corner of the frame member. The panel abuts the frame member at the peripheral wall with the exterior surface of the panel forming a tangential cord to the frame member&#39;s surface. The panel sits in the recess space  1106  created by the two surfaces to yield a tangential mating of the exterior surface. The bottom surface  1108  interfaces with the inside surface of the side panel and the peripheral wall  1109  mates with the edge of the side panel. 
     This embodiment has advantages of construction as it can be made from easily accessible materials, such as wood, plastic, metal stock with the bottom and peripheral walls or panel channels being formed by mills, routers or other tools. 
     The embodiment may be made out of lengths of any suitable material. As an example, it may readily be formed from 2×2 wood with the panel channels being cut out of one of the sides. The ends would form the connections with cross pieces  1112 , also made of 2×2 wood, with the panel channels appropriately formed in them. 
     The exterior corners  1102 , both of the sides of the frame member and the ends of the connector sections would be rounded by any common method to yield the curved exteriors of the within invention. 
     The inside surface of the frame members may be formed, machined or created in any suitable shape, such as an inside corner  1114  in FIG. 15, a curved or a flat, or other surface to accommodate attachments on the inside of the structure, such as drawer or shelf anchors. 
     The advantage of being made out of common stock allows for customization and easy repair. The end connection sections also allow for common attachment methods between the frame member and cross members. Additionally, making the corner ends and the intervening side piece as a single piece, there is less assembly required. Finally the end and side piece as a unitized frame member yields greater structural strength to that frame member including the end connector parts. This would help in loading of the complete frame. 
     In addition to the various mechanical fasteners discussed above, the panel may be secured to the panel recess using adhesives disposed between the contact surfaces of the two components. More than one type of fastener may also be used at the same time. Similarly, the various embodiments discussed above may be combined in one structure or even in one component without departing from the scope of the invention. 
     The invention and the best known mode of working it have been disclosed above in order allow practice of the invention by those skilled in the art, subject to retained patent rights. Many equivalents, substitutions and alternatives beyond those specifically detailed above will be obvious to those skilled in the art, without departing from the scope of the invention. Nothing in the above disclosure in any way limits the scope of the invention, which is limited only by the claims below.