Abstract:
A rigid tubular member of variable length and rectangular cross-section adapted to be sized, flared and conjoined with at least one other rigid member to create a variety of tubular member frameworks for greenhouse construction, and the like. Each member is provided with a plurality of elongate, linear groovings, either located proximal to, or coincident with, the external and/or internal elongate seams of the member, with the inscribed sets of groovings are such being of a depth sufficient to facilitate separation under manual force of at least one, up to four, of the end sidewall segments, providing flared end segments, either disposed at right or acute angles, which segments are adapted to be fastened to another rigid member in any of several locations, along it, in the course of a framework erection.

Description:
CROSS-REFERENCE TO OTHER APPLICATIONS 
     This is a regular patent application submitted for a filing receipt under 35 U.S. Code Section 111(a). It claims priority from a provisional patent application submitted under 35 U.S. Code Section 111(b), accorded Ser. No. 60/081,869, filed Apr. 16, 1998. 
    
    
     FIELD OF THE INVENTION 
     The field of the invention are hollow structural metal or rigid members that are generally rectangular in cross sectional shape but with two opposing sides slightly wider than the other two opposing sides and with linear grooving formed near or upon the seams for the purpose of selective and controlled flaring of the tubing ends. 
     BACKGROUND OF THE INVENTION 
     Many modern greenhouses utilize elongated metal hollow tubing to construct various elements of the structure. Both square and rectangular cross-sectional shapes are utilized, as well as round and elliptical shapes. These are usually standard in cross sectional size, and typically measured by the outside dimensions of the cross-section. 
     Several wall thicknesses of steel are available in standard gauge dimensions (such as 12 gauge, 14 gauge, 16 gauge, etc.) to allow for a wide range of structural strength combinations. When hollow structural tubes are created from rigid materials that can be extruded, (such as aluminum or plastic), or from cold rolled, steel sheeting; the range of wall thicknesses is limitless. 
     Most of these structures are assembled on site, in an erector-set-like fashion. In many cases, erection is performed by employees of the owner of the building, who are non-experts the practice of building structures. They also usually have limitations on the tools available to them; although, standard wrenches, drills, saws, etc. needed to build an erector set are usually available and familiar. Because the height of walls and rough opening sizes for equipment needing to be installed usually vary from structure to structure, tubing members are usually shipped in long standard lengths. Measurements are then taken on site as the structure is built, and the standard tubes are cut down to the desired lengths. 
     A typical gable end of a greenhouse will usually be formed by a series of vertical hollow tubes being mated to horizontal hollow tubes to create openings for necessary fans, shutters and doorways. Most of these junctures of tubing members create 90° angled to interconnections, and usually employing 90° angle brackets. The typical angle bracket is usually first bolted, or otherwise fastened, to the side of a vertical post and then the horizontal member is fastened to the other side of the 90° angle bracket. If two angle brackets are used at a joint, this basically creates a two point mechanical junction at the joint (even if more than one fastener is used in each side of each 90° angle bracket). 
     The roof line of many greenhouses presents a Quonset-hut type or a bowed roof outline. When the vertical hollow tubing meets the outline of the roof bows, the junctions that are created form angles less than, or greater than, 90°. These angles change consistently along the roof bowing. The use of 90° angle brackets to form connections that are not 90°, are just not practical. In those cases, specially adapted end brackets are needed to join the vertical or horizontal members to the changing angles of the roof bow. These special brackets also rely on fasteners to clamp the special bracket to one or both sides of the bow, and then fasteners to connect the bracket to the vertical or horizontal structural member. This resulting connection of the prior art also usually results in a two point mechanical junction at the joint. 
     It is a principal object of the invention to provide a tubing member that can utilize an end portion of it&#39;s own length of material to readily construct an interconnection with another tubing member of the same cross-sectional size, using standard and readily available fasteners, but without the use of 90° angled or special brackets, and without the need for welding these members to each other. 
     It is another object of the invention to provide biasing grooves continuously along the longitudinal dimensions of the tubing, to selectively allow the end sides of the tubing to be split away and then flared outward, in a controlled manner, so as to create the fastening flanges that allow the two tubes to be reliably conjoined together at various angles of inclination. 
     A further object of the invention is to allow the internal dimension of two opposing longitudinal sides of the tube to be equal to, or slightly exceed, the external dimensions of the other two opposing longitudinal sides which will enable the two unflared ends of the tube to is span and overlap(?) the narrower dimension of the same sized tube. 
     A yet further object of the invention is to allow the person who is erecting the new structure to utilize one sized (squared or rectangular cross-sections) structural members to create both horizontal posts and vertical beams without needing various sized structural members, or various sized brackets, for accomplishing variously angled connections. 
     A still further object of the invention is to allow the installer to create end joints and tubing interconnections mechanically with simple fasteners that result in a three or four point mechanical interconnection on many junctures. 
     Another object of the invention is to create stable multi-rigid tubing interconnections that allow the external surfaces of the completed structure to be relatively free of protruding lugs and edge brackets, which protrusions would hinder fastening of sheet-like materials over the framed structure. 
     Still another object of the invention is to allow the tube to selectively allow the sides of the tubing to be split away and then flared outward, in a controlled manner, so to create the fastening flanges that allow the tube to be reliably conjoined with flat surfaces or the edges or corners of flat surfaces. 
     Still another object of the invention is to allow the tube to selectively allow the sides to of the tubing to be reliably conjoined with structural members that are rounded, elliptical, angular, larger, or smaller than the tube. 
     SUMMARY OF THE INVENTION 
     The present invention provides improved hollow structural tubing members that are adapted to allow integral interconnection flanges to be easily fabricated from the longitudinal ends of the tubing, by selectively flaring out one or more of the sides of the tube. The tubing, in a preferred embodiment, will be made having a basically square, or rectangular, cross-sectional configurations. The internal corners will not have much of an internal radius so that they form substantially 90° corners. In the preferred embodiment, one pair of opposing internal sides of a given tubing will have an inside dimension that is the same as, or slightly exceeds, the external dimension of the other two opposing sides. 
     Elongate, linear grooves are formed into the longitudinal planar walls of the tube, either internally or externally, or both. These grooves will be located proximal to or at the elongate seams of the tube, along the elongated comers of the tube. Such grooves are specifically provided to weaken the tubing walls at precise points (edges) near the corner seams. This feature will provide shear line(s) along these grooves. A special flaring tool, will be employed, which will have a slotted chamber in the tool working face, that allows it to readily extend over the somewhat variable wall thickness of the tubing. When this special tool is inserted inside the longitudinal end of the tube, and is projecting over one of the sidewalls of the tube, and while the tube is held firmly in place, as in a vice, a levering force is exerted on the handle end of the tool in an outward arcuate direction from the tube. The grasped side of the tube will split outwards, breaking away cleanly from the two adjoining sides of the tube, that are otherwise integral, at 90° angles to the one side being split away. The linear grooves will assure that the side splits away along the weakening grooves, resulting in the tube end bending outwards (or flaring) of the side that is being split away. The angular degree to which such split side is flared out will readily conform to the angle desired for the flange to provide an interconnection with another structural member or surface, either at a right angle or an inclined one. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING (22 FIGS.) 
     FIG. 1 is a gable end view of a contemporary greenhouse having an arcuate-roofed structure, employing in tie structural framing, a variety of the tubular members of the present invention; 
     FIG. 2 is an enlarged, fragmentary end view of the end structure of FIG. 1, depicting same with some greater resolution; 
     FIG. 3 is perspective view depicting a prior art mode of conjoining two rectangular section, tubular members at a right angle, using dual 90° angle brackets; 
     FIGS. 4P,  4 S, and  4 E are perspective, side elevational, and longitudinal end views, respectively, of a first embodiment of the present invention, depicting an improved mode of conjoining certain tubular members of dissimilar cross dimensions; 
     FIG. 5 is a perspective view depicting another prior art mode of conjoining two rectangular members at a right angle at their longitudinal ends using one angle bracket of 90°; 
     FIGS. 6P,  6 S, and  6 E are perspective, side elevational, and longitudinal end views, respectively, of another improved mode of conjoining tubular members at the longitudinal ends of a pair of them; 
     FIG. 7 is a perspective view depicting a prior art mode of conjoining two members at a right angle, like that depicted in FIG. 3 using dual brackets, but now having been rotated spatially 90°; 
     FIGS. 8P,  8 S, and  8 E are a perspective, side elevational, and longitudinal end views, respectively, of another mode of conjoining at a right angle two rectangular, tubular members, which are each of substantially the same cross dimensions (squared); 
     FIG. 9 is an end elevational view of the next to final step for providing the single stepped-out finger-like end flaring (first stage) that overlaps the vertical member, with the results as seen in FIG. 8E; 
     FIGS. 10B and 10P are successive perspective views of one longitudinal end of a prior art rectangular tubular member, before and after cold working, which member lacks the groovings pretreatment feature of the present invention, but where an abortive effort was made to provide a discrete single flared finger, by mechanical leveraging; 
     FIGS. 11S,  11 E, and  11 T, are end, side, and top elevation views, respectively, of the conjoining of two tubular members, one of this invention, mated to a prior art round tube, at acute/obtuse angles; 
     FIGS. 12P and 12E are perspective and end views, respectively, of one angular member conjoined to one tubular member in a planar mode, at an interior acute angle, with flanges to be drawn from the one longitudinal member angled end, presenting one flared finger (and one sidewall) of the inclined member, serving as the dual areas of attachment to the horizontal tubular member; 
     FIGS. 13P,  13 S and  13 E are perspective, side elevation, and end elevational views, respectively, of one mode of conjoining one channel member (three sides as in FIG.  19 ), to one tubular member, being oriented acute angularly, now presenting three flared fingers, with the flanges all drawn from the one longitudinal channel member end, as projecting and providing three areas of attachment to the horizontal tubular member; 
     FIGS. 14R and 14S are longitudinal end views of a pair of tubular members, one of a rectangular cross section and the other of a squared cross section, each being provided with a plurality of longitudinal grooving lines coincident with (or proximal to) the elongate seams, on both of the inner and outer surfaces of the two members; 
     FIGS. 15R and 15S are longitudinal end views of another pair of members (rectangular and squared cross sections, respectively), each being provided with only a configuration of external grooving lines, located coincident with the elongate outer seams of each of such members; 
     FIGS. 16R and 16S are longitudinal end views of two tubular members (rectangular and squared cross sections, respectively), being provided with paired sets of longitudinal groovings, each pair bracketing the outer elongate seams of such members; 
     FIGS. 17R and 17S are longitudinal end views of two tubular members (of rectangular and squared cross sections, respectively) provided with elongate groovings, but only provided along the internal seams, with each linear grooving being located at each elongate corner of such member; 
     FIG. 18 depicts a tubular member of a rectangular cross section, now provided on one planar surface with two dissimilar, laterally projecting, hooked ledges, which ledges are adapted to receive an elongate wire spring element (not seen), which spring will serve to retain any overlapping sheeting (not seen) within the single sidewall external channel of the tubular member; 
     FIG. 19 is a three sided channel member of rectangular cross section, provided with both inner and outer longitudinal groovings located along its two elongate seams, having configurations like the groovings of FIGS.  14 R/S; 
     FIG. 20 is a two sided L-angle member provided with inner and outer longitudinal groovings, along its single elongate seam, like those of FIG. 19; 
     FIGS. 21S and 21T are side and top elevational views, respectively, of a elongate levered tool used for exerting a selective shearing force upon an open tubular end of a tubular member of the present invention and thus effecting the flared fingers, such as are depicted in FIGS. 4P,  6 P,  8 P,  11 S, and  12 P and  13 P; and 
     FIGS. 22A and 22B depict successive steps for the rotational shift of the tool of FIG. 21S after downward exertion, which produces a first outwardly projecting flange at one longitudinal end of a tubular member of the invention, and at any others, as needed. 
     FIGS. 23A,  23 B,  23 C, and  23 D are a longitudinal end views of a complemental set of rectangular cross-sectioned, tubular members, dimensioned to be snugly end-fitted one to another, when fabrication needs invite use of variably dimensioned tubings in a construction like that of FIG. 1; 
     FIGS. 24A and 24B are longitudinal end views of the similar tubular member having a rectangular cross-section and paired sets of external longitudinal groovings, with FIG. 24A denoting the internal longitudinal groovings located proximal to the external groovings and the location of external midwall, longitudinal groovings. FIG. 24B denotes sets of external pairs of groovings omitting the internal groovings; 
     FIG. 25 is a perspective schematic view of how a single stock tubular member can be variably end-modified (four variations) to provide both flared and lapped fingers for conjoining the member relative to an underlying linear edge of a mounting surface; 
     FIGS. 26P,  26 T,  26 S, and  26 E are perspective, top elevational, side elevational, and end elevational views, respectively, of a longitudinal ends conjoining of a pair of tubular members, each identically modified to include a longitudinal dimension, elongate recesses (or chambers), which recesses are also adapted to receive a depicted elongate spring clip, that will serve to retain a tucked-in sheeting (not seen); 
     FIG. 27E is a longitudinal end view of the horizontal member of FIG. 26P, now isolated from the conjoined vertical member of FIG. 26E, depicting an example of how tubing can be extruded in one piece with secondary uses built into the extrusion, in this case, for an elongate spring clip that is retained therein while it engages a flexible sheeting (not seen); 
     FIG. 28 is a side elevational view (partly in vertical section) of three tubular members, but now conjoined at right angles to provide a skeletal framework for an overlying wooden work bench. 
     FIGS. 29A to F depict the variety of end flange segments, producible from the longitudinal ends of a rectangular cross section tubing (See. FIG. 14R) for both right angle and acute angle conjoining to planar surfaces, like walls or ceilings; 
     FIGS. 30A to  30 G depicts the sequence of steps involved in converting a stock steel sheet to a rectangular cross section tubular member provided with a single longitudinal seam at each internal corner seam of the member (groovings provided on the inwardly folding surface); and, 
     FIGS. 31A to  31 F depicts the sequence of steps involved in converting a stock steel sheet to a rectangular cross section tubular member provided with a single longitudinal seam at each external corner seam of the member (the groovings initially provided on the outwardly folding surface). 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the gable end elevation view of a greenhouse structure (FIG.  1 ), a plurality of conjoined tubular members are depicted, involving both of arcuate and linear members, with right angle and acute/obtuse angle interconnections being provided. Gabled end  30  has: at least two right angle squared member unions, located intermediate of the longitudinal ends of horizontal members, such units as  32 L and  32 R; a right angle, squared member union located at the longitudinal ends of two tubular members, like  34 L/R; plural right angled, member unions, located intermediate of the ends of the vertical members, like  36 L/R; plural acute-angled, unions of two members, intermediate of the longitudinal ends of one inclined member, like lower  38 L/R, like middle level  40 L/R, and upper level  42 L/R members; Framed larger rectangular opening  44  would serve as a door position; higher rectangular opening  46  would serve as a fan-jet opening (intake shutter); left side, squared opening  48 L serves as a fist exhaust fan (not seen) opening, and opening  48 R serves as a second exhaust fan (not seen) opening. The elongate arcuate member  50  would present a uniform roof bow which will support the affixing of planar roof panels, or flexible sheeting (not seen), like the known Quonset style modules. 
     The broken-out side elevational view of FIG. 2 also depicts the plural, varied angle conjoining of tubular members of the present invention fabricated according to the present invention, in greater detail. 
     In the perspective of FIG. 3 is depicted a typical joinder means of two tubular members  52  and  54 , according to prior art practice. Two opposing L-brackets,  56 L/R, are the sole means of holding members  52  and  54  together, but providing strength only in the direction of the plane defined by such conjoined tubular members. 
     In FIGS. 4P,  4 S, and  4 E (perspective, side elevation and end elevation, respectively), are shown exemplary rectangular hollow tubular members,  58  and  60  in which the wider outside side dimension is 1.78:, the narrower outside side dimension is 1.5″, the wall thicknesses are ⅛″, and the inside dimension of the wider side is 1.53″, or slightly wider, than the outside narrower side dimension. 
     In the perspective view of FIG. 4P, a four way conjoining of two right angled, tubular members,  58  and  60 , is seen. The lower longitudinal end of vertical member  58  has been preworked to provide two opposing fingers,  62 L and  62 R, produced by a longitudinal end flaring-out tool means, to be disclosed later. These fingers provide bolting platforms for screw fasteners, like  64 L and  64 R. The remaining two sidewall fingers,  66  and  68 , are integral extensions of the upper member  58  lower end  70 . They serve to snugly straddle the underlying horizontal member  60 . These laterally aligned sidewalls ( 66 / 68 ) are also the platforms for two other fasteners, like  72 F and  72 B (in FIG.  4 E), which then provide a tube connection strength in all four directions. The linear groovings  73 L/R are seen in both of FIGS. 4P and 4S. Linear groovings,  75 U/L, are seen in both FIGS. also. 
     In the side elevational view of FIG. 4S, the narrower cross-dimension  74  (typically 1.5″ on this exemplary view) of upright member  58  is seen, as is the depending parallel sidewalls  66 , (and  68 ) which are spaced apart by appropriate cross-dimensioning of these members so to snugly straddle the narrower cross-dimension  76  (FIG. 4P) of underlying member  60 . 
     The end view of FIG. 4E depicts three of the four fingers/sidewalls ( 62 L,  66 , and  68 ), that interlock tubular members  58  and  60 .The wider cross-section  78  of member  58  is 1.78″, being such that the depending sidewalls, like  66  and  68 , slidingly engage the narrower surface  76  of horizontal tubular member  60 . 
     In the perspective view of FIG. 5, is depicted another prior art tubing end joinder of two rectangular tubular members,  80  and  82 , providing for only a single L-shaped, right angle bracket  84 , aligned inwardly. This provides but a single point interconnection with structural strength only, against outward divergence of the two members in their vertical plane. 
     In the perspective view of FIG. 6P, a three surface interconnection is provided by a modified upright member  86  of the present invention. Inwardly projecting finger  88  (formed from flaring one longitudinal wall of member  86 ), provides an inner L-bracket connection with member  90  (fastener  95 ), while parallel depending sidewalls,  92 F and  92 B, straddle upper surface  94  of underlying horizontal member  90 . The unflared sidewalls  92 F/B are traversed by fasteners  96 F and  96 B (FIG.  6 E). This configuration provides a three surface connection of members providing inherent strength against torsional forces in three directions. 
     The side elevation of FIG. 6S, shows the three point connection, profiling the split out, horizontal flanged finger  88 . The wider dimension ( 86 W FIG. 6P) of upright member  86  snugly straddles the narrower dimension (not seen) of horizontal member  90 . The end elevational view of FIG. 6E also depicts the three surface end mating of the members. The elongate linear groovings, like  96 L and  96 R, are depicted which facilitate the creation of end split off, like flanges  88  (FIG.  6 S), resting on the upper surface of member  90 . 
     In the perspective view of FIG. 7, is depicted a prior art, intermediate point conjoinder of a tubular vertical member  100  and a horizontal member  102 , along with their is two brackets,  104 U and  104 L, which provide bilateral strength in the plane of the two members only. 
     In FIGS. 8P,  8 E,  8 S and  9  are shown squared tubular members  106  and  114  attached at 90° angles to each other, to provide four directional strength. The preferred procedure to make this joint is to bend out  108 U and  108 L, then bend out  110 L, then fasten  108 U,  108 L, and the unflared side, then use tool to bend  110 L back to straddle. 
     In the perspective view of FIG. 8P, the longitudinal end of horizontal member  106  has been flared doubly to provide upwardly and depending fingers,  108 U and  108 L, and a stepped out, finger  110 L, drawn from sidewall  112  of member  106 . The opposing vertical sidewall (not seen) is unflared and not stepped-out, can still straddle the cross-dimension  114 N of upright member  114 . The unilateral stepped-out finger  110 L is achieved by bending same inwardly (from the intermediate position of FIG. 9) into parallel alignment of the sidewall  114 W of member  114 , after the other three fingers straddle upright member  114 . This provides a four surface tubular interconnection with structural strength in four directions. Note the elongate linear groovings ( 116 L/R and  119 L/R) on the external surfaces of both members. In the side elevational view of FIG. 8S, the expanded width of finger  110 L is depicted as embracing the dimension ( 114 N of FIG. 8P) of upright member  114 . In the end view of FIG. 8E, the four of the surface fasteners of this embodiment ( 118 U/L/F/B) are shown. 
     In FIG. 9 is depicted the pre-final fabricating step in the flaring of horizontal member  106 . The vertically flared fingers ( 108 U/ 108 L) and the unflared sidewall finger (not shown) are fastened to the vertical members  114 . Prior to anchoring, the right side sidewall finger  110 L is oriented outwardly (via tool levering) and is now positioned for manual bending about the upright member  114  to overlap same, so to give the four surface interconnection of FIG.  8 E. 
     In the view of FIGS. 10B and 10P, are depicted the alterations wrought upon one longitudinal end of a rectangular tubular member  120 , before and after cold working, where the prior art member lacks the longitudinal pre-grooving features (e.g.,  116 L/R in FIG. 8P) of the present invention. By mechanical leveraging with the tool of FIG. 21, an effort was made to provide a discrete, outwardly flared finger  122 . The result was the poorly separated, sidewalls distorted, and ragged edged partitions  124 L/R of FIG.  10 P. Also, an internal protrusion  121 , bulging inwardly at external bulge  123  is caused by the mechanical leveraging tool of FIG.  21 . The member is unusable for planar interconnection. 
     In the side elevation view of FIG. 11S, a four surface interconnection has been provided for vertical member  124  (tubing of this invention), and inclined member  126  (a round tube not of this invention). Vertical member  124  has two opposing sidewalls (not seen) flared outwardly, i.e., finger  126 L at an acute angle, and finger  126 U at an obtuse angle, so to make dual contact on the surface of inclined member  126 . The vertical sidewalls ( 124 F and  124 B, FIG. 11E) of member  124  are cut transversely to conform their edges ( 128 F/B) to the changing angle of gable end bow (compare FIG.  2 ). This configuration provides for four fastener surfaces, and thus yields four directions of structural stability. The top view of FIG. 11T depicts the contacting surfaces and associated securing fasteners. In the end view of FIG. 11E, the unflared sidewall ( 128 F) is fastened to other gable end bow of member  126 . The opposing sidewall  128 B is flared outwardly to overlap the opposing linear surface of the bow member  126 . 
     The perspective view of FIG. 12P depicts an angular structural member  132  connected to a tubular structural member  136 . Member  132  (pre-flaring) is shown in the end view of FIG. 20, as two-sided channel  182 . A single, split out flanged finger  130 U and adjacent sidewall extension  130 F, of inclined member  132 , provide a two surface connection for fasteners  134 U/F. Here one side of inclined member  132  connects with the wider cross dimension  136 W of horizontal member  136 , while the second side  132 F of member  132  connects to the narrower cross dimension  136 N of horizontal member  136 . This is better depicted in the end view of FIG.  12 E. 
     In the perspective view of FIG. 13P, the lower member  142  has been rotated 90°. The inclined channel member  140  is fabricated with a single flared finger  140 U (obtuse angle), so that depending sidewall ends  140 F and  140 B straddle the narrow dimension  142 N of horizontal member  142 . The three surface connection of members (secured with fasteners  144 U,  144 F, and  144 B) is better seen in the end view of FIG.  13 E. The elongate linear groovings of member  140 , like  146 L, and  146 R, are quite proximal to the linear seams of tubing  142  and channel  140 , and are depicted in both FIGS. 13P and 13E. The side elevation view of FIG. 13S is also common to the embodiments of both FIG.  12 P and FIG. 13P, as the front side conjoinder shows a two surface connection, from this perspective. 
     In the related views of FIGS. 14R and 14S are seen both rectangular and squared cross-sectional tubular members, each with a plurality of longitudinal weakening groovings. In FIG. 14R, the inner comer seams  150 A,  150 B,  150 C, and  150 D, are each provided with a linear groovings,  152 A-D, for the length of the elongate member, providing an inner set of length. These incisions constitute useful weakening groovings that permit a clean separation and finger flaring out of each, or all, of the end walls, as may be required for a particular assembly. Companion squared member  145  is similarly scored, both internally ( 151 A-D) and externally ( 158 A-H) of its elongate seams. 
     In the paired embodiments of FIGS. 15R and 15S, the groovings configuration is altered. No inside seam groovings are incorporated, while only the external seams each have a single initially V-shaped grooving  160 A,  160 B,  160 C, and  160 D. These also will facilitate clean separation and flaring out of each, or all, of the longitudinal end sidewalls. Similarly so with squared cross-section of FIG. 15S ( 161 A-D). 
     In the paired embodiments of FIGS. 16R and 16S, only an external pair of groovings  162 A/B,  162 C/D,  162  E/F, and  162 G/H are included at each elongate seam. They are in a like configuration to that of the external groovings of FIG. 14R, and will still provide for selected weakening lines upon tube end flaring. The squared cross sectional member of FIG. 16S are similarly scored ( 164 A-D) on the external seams. 
     In the final cross sectional paired views of FIGS. 17R and 17S, only the internal elongate seams are provided with linear grooves,  164 A,  164 B,  164 C, and  164 D, for the elongate member length. These will provide the weakening lines for end flaring of any or all of the four sidewalls,  166 A-D. The squared member of FIG. 17S is similarly scored ( 167 A-D)on the internal seams. 
     In the cross sectional view of FIG. 18, the rectangular member of FIG. 14R has been modified in the process of extrusion ( 168 ) to present, on one surface, two laterally projecting ledges, dissimilarly configured. These elongate, seam-integral ledges ( 170 U and  170 L) present an externally located and recessed channel  172 , adapted to receive flexible sheeting (not seen), when the member  168  is positioned, in either the vertical or horizontal position, in the end wall of a greenhouse, like that of FIG. 2, and when vertical sheeting is to be draped and secured over the gabled end of the structure. A flexible wire spring device (not seen), such as I have disclosed in my earlier files, now U.S. Pat. No. 5,671,795 granted Sep. 30, 1997, can be used here to retain a draped over sheeting firmly within channel  172  of the horizontal-post-like member  168  of FIG.  18 . The flexible sheeting clasping ability, enabled by the protecting flanges  170 U and  170 L and channel  172  is not part of this invention, but is representative of how an ability to clasp flexible fabric to these structural members can be molded into the shape of the structural member when creating these shapes from extrudable materials. Similarly, with extruded members, the ability to mold other external sides of the tube can be utilized as an added benefit to the extruded shape while still allowing the flaring of ends of the tubes and the resulting conjoining of tubes, such as further described in FIGS.  26 . 
     In the FIG. 19 cross sectional view, a three sided channel member  174  is depicted, having a generally squared cross section, and being provided with a pair of offset groovings,  176 A/B and  176 C/D, located about the external elongate seams; and a single longitudinal grooving  178 A and C, located at both internal corners,  180 A and  180 C. The sectional view of FIG. 20 depicts a L-shaped, elongate member  182  having a set of both external and internal groovings,  184 A/B and  186  like the ones depicted in FIGS. 14S and 19. The use of members  174  and  182  in FIGS. 19 and 20 are shown in connections depicted in FIGS. 13P and 12P, respectively. 
     The schematic views of FIGS. 21T and 21S present one embodiment of an isolated flaring tool, useful with the structural member interconnections (as in FIG. 2) of this invention. The preferred embodiment of a flaring/bending tool  191  shown in FIGS.  21 S/ 21 T, side and top views, respectively, has a narrow tool-head  194 N and an opposing end wide tool-head  194 W welded to each end of the tool handle  192 . The tube bending slots  196 N and  196 W in the narrow tool-head  194 N and the wide tool-head  194 W, respectively, are slightly wider than the thickness of the tubing walls  200 N/W, and  201 N/W. The width of the narrow tool-head  194 N is slightly narrower than the narrower internal sidewall  200 N of the tubing  198 , and the width of the wider tool-head  194 W is slightly narrower than the wider internal sidewall  200 W of the tube  198 . 
     When the narrow tool-head  194 N is inserted between the wider sides of tube  198  and the slot  196 N is projected down over the end of the narrow tubing sidewall  200 N, as in FIG. 22A, the tool is in a position to begin bending out the end of the sidewall  200 N, of FIG.  21 T. As the tool handle  192  is pulled and rotated in the direction of the arrows shown in FIG. 22B, the narrow sidewall  200 N in FIG. 21T is bent or flared outwards and downwards to create the flare  200  in FIG.  22 B. The upper and lower flaring grooves  199 U/L in FIG. 21T would allow a controlled break-away of the end of sidewall  200 N from the opposing two sidewalls  200 W and  201 W. This step can be continued on one or more of the other end sidewalls of the structural members as the conjoining of the tubular, channel and angular, members of this invention may be required. 
     In the related end views of FIGS. 23A-D, are seen a complemental set of four rectangular cross-section tubular members, configured to have complementally sized cross-sections, such that they permit the snug lodging of the larger side dimension of one member within the shorter side-dimension of the next larger dimensioned tubular member; for example, the higher dimension  206  of tubular member  202 A will lodge snugly within the narrower vertical dimension  208  of tubular member  202 B. 
     Similarly, so with tube “B”, the wider dimension  210  of tubular member  202 B will lodge snugly within the shorter width between the inner sidewalls  212  of tube member  202 C, while the “C” tube  202 C has higher outer dimension  214  which will snugly fit into the inner vertical dimension  216  of “D” tube  202 D. These examples of complemental tubular cross-section dimensions provide for a variety of abutting ends pairing of rectangular tubings having close tolerances and adapted for pressure-fitted end engagements. 
     In the two longitudinal end views of FIG.  24 A/B, in addition to the depicted inner and outer corners sets of paired groovings, first shown in FIGS.  14 R/S, there are now provided, transversely and midway of each of the four planar external surfaces  220 N/S/E/W of tubing  220 , a longitudinal linear grooving located at  221 N/S/E/W for the purpose of assisting the installation of self-drilling fasteners  64 L as seen in FIG. 4P, to be started within the drill-guide grooves  221 N/S/E/W. In the machine extruded tubular embodiment of FIG. 24A, there are also provided elongated, paired outer grooves  222 A/D  223 A/B,  222 B/C, and  223 C/D, and elongate, rounded inner grooves,  224 A/B/C/D. Inner grooves  224 A/B work together with opposing outer grooves  223 A/B, to provide controlled sidewall separation lines to enable flaring outward of side  220 E. Inner grooves  224 B/C work together with opposing outer grooves  222 B/C to allow controlled flare-out of sidewall  220 S, etc. 
     In FIG. 24B, the outer grooves  222 A/D,  223 A/B,  222 B/C, and  223 C/D are deeper than the comparable outer grooves in FIG. 24A, and do not require the inner corner grooves, such as  224 A/B/C/D as in FIG. 24A, in order to effect controlled sidewall separation lines for flareout of the respective sides as illustrated in FIG.  25 . 
     The perspective views of FIG. 25 depict how longitudinal ends of tubular members,  228 ,  230 ,  232  and  234 , of the present invention can be adapted to be mounted upon the linear edge of a subsisting solid object  220 , like a concrete slab. On tubular member  228 , as the four fingers are produced using the tool of FIG. 21S, one finger (not shown) is eliminated by flexing the flared tab several times, until it breaks off at the bending line  228 E. One finger  228 F depends externally to be fastened to the slab sidewall  220 S, and two fingers  228 L/B are flared outwardly, to be fastened to the horizontal plane  220 F of slab  220 . On tubular member  230 , there are one depending finger  230 F, and three flared fingers,  230 L,  230 R, and  230 B. 
     Corner position tubular member  232 C has two depending end segments,  232 F and  232 R, and two flared fingers  232 L and  232 B, all being slab fastened. Inclined member  234  (like that of FIG.  12 P), is fastened to slab  220 S having one depending sidewall finger  234 R and three flared fingers,  234 L/F/B. This composite Figure depicts many of the useful end tube flarings that can be obtained by modifying the squared tubular ends of the tubular members of this invention. 
     In the views of FIGS. 26P,  26 T,  26 S, and  26 E, an end-conjoining of two identically configured tubular members,  240  and  242  (like that shown in FIGS. 6P,  6 E, and  6 S), are depicted with one major variation. Each of the conjoined members are provided with an integral elongate external recess,  240 R and  242 R, respectively. These elongate recesses are effected by modification of the extrusion die profile, well within the skill of the metal fabricating arts, to provide assembled tubular members,  240 / 242 , as appearing in end FIG.  26 E. While the U-shaped recesses,  240 R/ 242 R, are depicted as being integral with the shorter dimension  240 N of the horizontal tubing  240  of FIG. 27E, they can as readily be provided for the longer vertical dimension  240 W of tube  240 . The side elevation, end elevation, and perspective views of FIGS.  26 S/E/P show the end-conjoined pair of tubes,  240 / 242 , using two sidewall fingers  244 R and  244 L, and one horizontal flared finger  244 T. The end and top plan views of FIG.  26 E/T depicts how the three fasteners,  246 A/B/C, affix the tubes to one another with stability. 
     The retainer clips  248 / 250  in FIGS.  27 E/ 26 T snap resiliently into the channels  240 R/ 242 R of the modified tubular members. Clips  248 / 250  are a simple resilient V-shaped member of spring steel or plastic, which are shown engaged with flexible sheeting tucked into the channels,  240 R/ 242 R and anchored therein, when clips  248 / 250  are pressed between opposing inner lugs  252 U/L, which lugs are integral to the channel members themselves. This U-shaped clip and U-shaped channel is prior art and this configuration represents how features can be moulded into the sides of extruded tubes of this invention and still allow the tube sides at the ends to be flared out and utilized to construct various connections. 
     In the elevational view of FIG. 28, there is depicted how three tubular members,  264 / 266 / 268 , of this invention are conjoined at right angles to one another so as to provide a skeletal supporting framework, generally  260 , for an overlying planar bench surface  262 . Vertical member  264  admits internally of the end view cross section of final, horizontal tubular member  266 , having flared end  267 , and two unflared sides,  264 L/R. The other horizontal member  268  has a depending, right angle flared end segment  270 , a projecting, right angle flared finger  273 , aligned with the side of horizontal tube member  266 , and also a straightly aligned end segment  272 , overlapping horizontal member  266 . These modified end segments serve to conjoin the three members via the use of tubing sidewall fasteners  274 A,B,C and D, while the larger depending wood screw  276 , anchors the bench top  262  to the underlying tubular member framework  260 . 
     The composite views of FIGS. 29A-F show end modification of six tubular members,  290 ,  292 ,  294 ,  296 ,  298 , and  300 , which have been prepared to mount to any flat surface, such as a wall, floor or ceiling. The views of FIGS.  29 A/B show modification of two tubular members  290 ,  292 , to present flared outward segments  290 A/B/C/D in FIG. 29A, and like flared outer segments  292 A/B/C in FIG.  29 B. The sole difference is the comparable reverse flared segment  290 D, depicted in FIG. 29A, but not appearing in FIG. 29B, because the equivalent fared member has been flexed with a flaring tool, as shown in FIG. 21T, until it has been broken off through metal fatigue at its bending line (not shown). 
     In FIG. 29C, the ends of the four sides of tube member  294  have been flared outward at 90° angles to create four flared fingers,  294 A/B/C/D. Likewise in FIG. 29D, tube member  296  has three 90° flared fingers,  296 A/C/D, but the comparable finger  294 B in FIG. 29C is missing in FIG. 29D, because the finger (not shown) has been broken away along line  296 B with a flaring tool like shown in FIG.  21 T. Similarly, in FIGS.  29 E/F are seen comparable linear edges,  298 B/C and  300 B/C of the tube members  298 / 300 , where fingers (not shown) have been flexed with the tool in FIG. 21T, and broken away after metal fatigue occurred. 
     The sequence of tube forming steps for working with stock sheet steel (an alternate metal to aluminum extrusions and suitable for these purposes) are depicted in FIGS. 30A to  30 G. The stock sheet  310  of FIG. 30A is conventionally converted to the longitudinally and parallelly multi-grooved planar member  312  in FIG. 30B, using a rotatable multiblade lathe  314  or hardened wheels in FIG.  30 C. The resulting multi-grooved member,  316 , is first folded, as seen in FIG. 30D, along the outermost pair of grooves,  317 A/B, and drawn to opposing right angles,  315 A/B, as are depicted in FIG.  30 E. Then, the inward convergence of the sidewalls,  318 A/B, is next forced along the inner set of longitudinal groovings,  319 A/B, as depicted in FIG.  30 F. Finally, in FIG. 30G, the three sidewalls,  318 A/B/C, are converged to form a rectangular cross section for a resulting tubular member  320 . Conventional welding along the longitudinal seam  322  provides a sheet steel tubular member having structural integrity for conjoining with other such tubular members, of like materials of construction. Internal longitudinal flaring weakening grooves,  317 A/B and  319 A/B, provide for controlled flaring at the ends of the tubes such as shown in FIGS. 29A-29F. Sheet gauges range from 44 (very thin) to zero (relatively thick). Sheets ranging from gauges 16 to 3 are best processed with the bending tools described herein. 
     Another alternate sequence of the tube forming steps for working with sheet steel that results in providing external longitudinal flaring weakening grooves, such as shown in FIGS.  15 R/S, is illustrated in FIGS. 31A-31F. 
     The stock sheet  330  of FIG. 31A is conventionally converted to the longitudinal and parallel multi-grooved planar member  332  in FIG. 31B using a rotatable multiblade lathe or hardened wheels  334 . The resulting multi-grooved member  332  is first folded, as seen in FIG. 31C, along the outermost pair of grooves,  337 A/B, and drawn to opposing right angles,  335 A/B, as are depicted in FIG.  31 D. Then the inward convergence of the sidewalls,  338 A/B, is next forced along the inner set of longitudinal groovings,  339 A/B, as depicted in FIG. 31, FIG.  31 E. Finally, in FIG. 31F, the three sidewalls  338 A/B/C, are converged to form a rectangular cross section for a resulting tubular member  340 . Conventional welding along the longitudinal seam  342  provides a sheet steel tubular member having structural integrity for conjoining with other such tubular members of like materials of construction, with external weakening grooves  337 A/B/C/D, located proximal to each corner for controlled flaring as illustrated in FIG.  25  and FIGS. 29A-F. 
     In Operation 
     Often, the side of the tube opposing the side that was just flared outwards will also need to be flared outwards. This will result in a dual-finger configuration for an interconnection between two lengths of tube of the same cross-section. Because the inside dimensions of the wider longitudinal sides of the tube are equal to, or slightly exceed, the external dimension of the same tube size, the two unflared sidewalls of the first tube will slidingly engage the narrower sidewall of another length of the same sized tube. The two flared-outwards sides of the first tube will be brought into planar contact with one of the narrower sides of the second tube. 
     After perforation, one or more fasteners can now be placed through each of the two (or more) flanges formed by flaring outwards the ends of the wider sides of the first tube and through the one narrower side of the second tube if using a self-threading fastener (or by bolting through both narrow sides of the second tube). Also, one or more fasteners can now be placed through the two narrower width sides of the first tube that were not flared outwards, through the wider sides of the sidewalls of the second tube which the first tube straddles. 
     When interconnections provide right angled junctures at two longitudinal ends of two tubes, one wider sidewall of the first tube can be flared outwards, while leaving the opposing second wider sidewall unflared. The narrower width sides of the first tube can be slipped over the one end of the second tube, straddling one of the narrower sides of the second tube, for a three point connection. 
     Preferably, by the use of self-drilling fasteners they can be used to create the interconnection in one simple step of drilling and fastening at one time. Installers, who do not have ready access to such fasteners, can drill holes through the flanges and utilize standard bolts and nuts for securing the conjoined tubular members.