Abstract:
A truss including a first support member, at least one second support member and a connector connecting the support members. The first support member has a first substantially planar portion. The second support member has a non-planar cross section substantially along a length thereof and an end with a second substantially planar portion. The connector secures the first and second substantially planar portions.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to a structural member for construction of buildings such as houses. The invention has particular but not exclusive application in use as a chord for forming a roof truss for a building.  
         PRIOR ART  
         [0002]    A metal roof truss is commonly constructed with box-section chords and C-section web members. The box-section chords are formed by two C-sections individually roll formed and then further fabricated by dimple formation for locating and/or fastening by welding, riveting, hole punched and bolted or screwed to close the two C-sections. The fabrication of the section is a specialized operation and adds additional cost and time to the manufacture of a chord.  
           [0003]    Open sections are generally quicker and cheaper to manufacture than box-sections comprising two C-sections, but they lack the strength and stiffness required for chords. Thus, whenever open sections, such as channel and Z-sections are used in the fabrication of building frames and roof trusses, additional precautions such as providing oversized sections or additional structural support must be taken to compensate for their inherent strength deficiencies. This of course increases the cost of many structures formed therefrom.  
           [0004]    In addition, effecting the joints between top and bottom chords and between web members and chords mostly requires specialized joining members or shaping for welding which adds to the cost and complexity of such structures.  
         SUMMARY OF THE INVENTION  
         [0005]    A truss or other structural member formed from the combination of an open structural member and a chord having a c-shaped, closed or elliptical cross section and/or a second open structural member.  
           [0006]    In one aspect the invention broadly resides in an elongated open structural member having a cross-section including a minor flange, a major flange and a web interconnecting the flanges and having a section axis at right angles to the longitudinal axis of the structural member and passing through the flanges and wherein:  
           [0007]    the web includes a linear portion substantially coincident with the section axis and a divergent portion which extends to one side of the section axis;  
           [0008]    the minor flange extends to the one side of the section axis;  
           [0009]    the major flange extends from the divergent portion to the opposite side of the section axis, and  
           [0010]    the section configuration being such that an inverted and reversed corresponding open structural member is nestable within the open structural member with their respective linear section portions alongside one another and with each minor flange located in an abutting relationship against the underside of the adjacent major flange.  
           [0011]    The linear portion may be any suitable length but preferably the linear portion is extends along a major portion of the section axis between the flanges. The term “suitable” is qualified by the particular use of the open structural member and where a corresponding member is used the length of the linear portion suitably enables overlap of the linear section portions or portions thereof.  
           [0012]    The divergent portion may have any suitable shape. The divergent portion may be curved, straight, or comprise a series of straight segments. In a preferred embodiment the divergent portion is a single straight portion and the major flange extends at an acute angle from the divergent portion.  
           [0013]    The linear portion connects to the minor flange at its end opposite the divergent portion. Preferably the minor flange extends from the linear portion at an angle of substantially 90 degrees. Alternatively, the linear portion may include a second divergent portion which extends to the minor flange. The second divergent portion may be curved, straight, or comprise a series of straight segments.  
           [0014]    The minor flange is preferably shorter than the major flange and most preferably is shorter than the section of the major flange which extends between the section axis and the end of the major flange remote from the divergent portion, and hereinafter referred to as its “free edge”. Preferably the intersection with the section axis occurs about midway across the-major flange.  
           [0015]    Preferably the flanges are substantially flat or at least parts which are substantially diagonally opposite with respect to the section axis are substantially flat. Preferably the flanges or at least the flat parts are substantially parallel.  
           [0016]    Preferably the open structural member includes a limitor to restrict lateral movement with respect to the section axis of connected members along the section axis. Preferably the limitor is a return flange extending along the free edge of the major flange.  
           [0017]    The major and/or the minor flanges preferably both terminate in a return flange. The return flange preferably returns substantially parallel to the section axis. Preferably the return flange of the major flange is spaced further from the section axis than the free edge of the minor flange so that a reversed and inverted corresponding open structural member may nest within the structural member.  
           [0018]    The open structural member is preferably asymmetrical in shape and allows the nesting of an inverted and reversed corresponding open structural member with the minor flange of one open structural member locatable within the major flange of the other open structural member and overlapping of the linear section portions.  
           [0019]    The invention in a further aspect broadly resides in an elongated open structural member having a minor flange, a major flange and a web interconnecting the flanges and having a planar web portion extending at right angles to the minor and major flanges, and wherein:  
           [0020]    the web includes a divergent portion which extends to one side of the planar portion;  
           [0021]    the minor flange extends to the one side of the planar portion;  
           [0022]    the major flange extends from the divergent portion to the opposite side of the planar portion;  
           [0023]    the minor flange and the major flange each have a return along their respective free edge, and wherein  
           [0024]    the configuration being such that an inverted and reversed corresponding open structural member is locatable with its planar portion alongside the planar portion of the structural member and each minor flange including its return being locatable within the confine defined by the adjacent return flange of the major flange.  
           [0025]    In another aspect the invention resides in a chord member for a truss, each chord member of the truss being an open structural member as described above whereby the chord member may be disposed with its major flange outermost and with interconnections between intersecting chord members being made by extending the web and minor flange of one intersecting chord member across the web and minor flange of the other chord member with the webs overlying one another enabling through fastening together. In such arrangement the webs overlap at joints for connection to one another such as by bolting or screwing or welding and, if desired disposed with their minor flanges nested within the major flanges of the opposing chord member.  
           [0026]    It is also preferred that the chords of the truss are interconnected by truss members which may be open section members suitably terminated for web to web connection to the webs of the top and bottom chord members.  
           [0027]    The assembled truss with the open structural member forming the top and bottom chord members with C-section truss members preferably has the chord members proud of the truss members thereby allowing stacking of the assembled truss and transportation of the stacks without risk of damage to the truss members by the overlying chord members. In contrast conventional box section chords have C-section truss members joined at their flat surfaces thereby causing the truss members to be proud of the chord members and exposing the truss members to damage during stacking and their transportation.  
           [0028]    In a further aspect the invention broadly resides in a composite beam formed by the nesting of two open structural members as described variously above in an inverted and reversed orientation with respect to each other with the minor flange of one member located within the major flange of the other member and overlapping of the planar portions and fastening means connecting the open structural members together.  
           [0029]    The open structural members may be prevented from lateral displacement with respect to one another by the fastening means but preferably they include returns along the free edges of the major flanges which restrain lateral displacement of the open structural members with respect to one another.  
           [0030]    Preferably the nesting of the open structural members as described above forms two closed sections thereby providing strength to the beam.  
           [0031]    A further aspect of the invention includes a truss including a first support member having a substantially planar portion; at least one second support member having a non-planar cross section and an end with a second substantially planar section; and a connector securing the first substantially planar section to the second substantially planar portion. The second support member may have a C-shaped or elliptical cross section. Also, the second substantially planar portion is a crimped version of the non-planar cross section. The connector may be a bolt or other suitable connector well known in the art. The end of the second support member may have third and fourth substantially planar portions arranged at angle to the second substantially planar portion. Further, this embodiment is not limited to one second support member and may contain a plurality of second support members connected to the first support member by the connector. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]    Several typical embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:  
         [0033]    [0033]FIG. 1 is an end elevation of an elongate open structural member;  
         [0034]    [0034]FIG. 2, 3,  4  are perspective views of the member;  
         [0035]    [0035]FIG. 5 is an end elevation of two members nested in reverse and inverted orientation with respect to each other;  
         [0036]    [0036]FIG. 6 a  is a front elevation of an assembled truss with open structural members as top and bottom chord members;  
         [0037]    [0037]FIG. 6 b - g  shows various connections on the truss shown in FIG. 6 a;    
         [0038]    [0038]FIG. 7 a - c  are views of the interconnection of two open structural members;  
         [0039]    [0039]FIG. 8 a - c  are views of different attachments of a C-section truss members to a chord;  
         [0040]    [0040]FIG. 9 a - c  show alternative connections between chords and truss members;  
         [0041]    [0041]FIG. 10 a - c  shows an alternative structural member; and  
         [0042]    [0042]FIG. 11 a - b  shows interconnections of closed section chord members and open structural members. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]    With reference to FIGS. 1, 2,  3  and  4  there is shown an elongate open structural member  10  having a minor flange  12  and a major flange  13  separated by a web  14 . A longitudinal axis  11   b  of the member  10  is shown in FIG. 2. The web  14  includes a planar portion  17  and a divergent portion  18 . A section axis  11   a  is coincident with the linear portion  17 . The minor flange  12  extends from the planar portion  17  at 90 degrees. The minor flange  12  includes a return flange  15 . The return flange  15  is parallel to the section axis  11   a.  The divergent portion  18  diverges from the section axis  11   a  at an acute included angle indicated by alpha. The divergent portion  18  is connected to the major flange  13 . The major flange  13  includes a broad planar flange portion  19  which is connected to the divergent portion  18  forming an acute included angle. The major flange  13  also includes a return flange  20  parallel to the section axis.  
         [0044]    As shown in FIG. 5, two elongate open structural members  30 ,  31  as described above are able to be nested with one member being in reverse and inverted orientation with respect to the other. To effect nesting minor flanges  32   a  and  32   b,  are located within major flanges  33   b  and  33   a  respectively in abutting relationship. In this position the respective web portions  34   a ,  34   b  partly overlie each other thereby allowing fasteners to join both members  30 ,  31  to prevent lateral movement. The abutting relationship of the respective flanges  32   a ,  32   b ,  33   a ,  33   b  prevents movement along the section axis. The nesting of the two elongate members forms two closed sections  35 ,  36  which provide strength and stiffening to the composite member.  
         [0045]    Roof trusses  40  as shown in FIGS. 6 a - g  are constructed with elongate open structural members forming top and bottom chords  41 ,  42  and C-section truss members  43 . The connection of the top chord  41  to the bottom chord  42  is shown in FIG. 6 b.  The major flanges  44 ,  45  of the top and bottom chords  41  and  42  respectively are outermost. The minor flange  46  of the top chord  41  is partially located and confined in major flange  45 . The rearward flat side  47  of top chord  41  partly overlaps frontward flat side  48  of the bottom chord  42 . There is shown an intermediate connection plate  49  between sides  47  and  48 . The connection plate  49  is attached to the bottom chord  42  by bolts  50 ,  51  and to the top chord  41  by bolts  50 ,  52 . An alternative connection is shown in FIG. 9 c  where top chord  60  is bolted to bottom chord  61  at  62 .  
         [0046]    Connections of the C-section truss members  43  to the chord members  41 ,  42  are shown in FIGS. 6 c ,  6   d ,  6   f . In FIG. 6 d  the truss members  43  are crimped and joined to the-top chord  41  by bolt  70 . In FIG. 6 e  the truss members  43  are attached to the bottom chord  42  by bolt  72 . The underlying truss members  43  are at least crimped to accommodate the connection. The connection shown in FIG. 6 c  has the truss member  43  connected by bolt  71  to the bottom chord  42 . The chords  41 ,  42  are proud of the truss members  43  in the truss  40 . A preferred connection includes the planar surface of the crimped end of the truss member secured to the planar portion  17  of the web  14 .  
         [0047]    The apex  80  of the truss  40  is shown in FIGS. 6 f  and  6   g.  An apex plate  81  serves to connect top chords  41  by bolts  82 . The apex plate  81  has recessed ribs  83  to provide additional stiffening. The apex plate  81  also has a recess  84  for the location of a C-section truss member  43 . The C-section truss member  43  is connected to the apex plate  81  by bolt  85 . Alternative connections in an apex are shown in FIG. 9 a  and  9   b.  In FIG. 9 a  top chords  63  and C-section truss members- 64  are connected by bolt  65 . Similarly in FIG. 9 b  the top chords  66  and C-section truss member  67  are connected by bolt  68 .  
         [0048]    In FIG. 7 a - c  there is shown chords  90 , 91  with major flanges  92 ,  93  outermost and minor flange  94  of chord  91  located partially within the major flange  92  of chord  90 .  
         [0049]    In FIGS. 8 a - c  there is shown attachment of crimped C-section truss members  95  to elongate open structural member chords  96  by bolts  97 . The C-section truss member  95  has end  98  crimped presenting a flat surface  99  for connecting to the chord  96 . The flat surface  99  is attached to the side of the web portion  100  opposite the narrow flange  101 .  
         [0050]    [0050]FIGS. 10 a - c  depict different embodiments of open structural member  10 .  
         [0051]    [0051]FIGS. 11 a - b  show another embodiment of a structure  110 , such as a roof truss or other structures well known in the art. The structure  110  includes an open structural member  10  connected to two truss members  112  with a single bolt  114 .  
         [0052]    Truss members  112  have a closed or substantially elliptical cross-section formed by sidewall  112   a  and an area of void space within the sidewall  112   a.    
         [0053]    As shown in FIG. 11 a,  the elliptical truss members  112  have an end  116  which is crimped such that the sidewall  112   a  of the elliptical truss member  112  is compressed to decrease the space therebetween.  
         [0054]    [0054]FIG. 11 b , which is a top view of FIG. 11 a  also shows the crimped nature of the ends of elliptical truss members  112 .  
         [0055]    Also as shown in FIGS. 11 a - b,  the crimped end  116  has two side portions  118  and  120 , which in a preferred embodiment form an angle β with a center portion  122 . The angle β at which the side portions  118  and  120  bend with respect to the center portion facilitates securing multiple truss members with a single bolt  114 .  
         [0056]    The center portion  122  is relatively planar and is secured to the planar portion of another structural member by a single bolt. Center portion  122  has sidewall  112   a  which in a preferred embodiment are closer together than the sidewalls  112   a  in the side portions  118  and  120 . The angle β at which the side portions  118  and  120  may bend with respect to the center portion facilitates securing multiple truss members with a single bolt  114 .  
         [0057]    Another feature of the connection of the truss members  112  to the open structural member  10  includes the substantially planar portion  17  of open structural member  10  abutting the substantially planar surface of truss member  112 .  
         [0058]    Although FIGS. 11 a - b  include two structural members  112 , the number of structural members which may be attached is not limited to two and may be one or several. Further, the invention is also not limited to the use of a bolt and other suitable connectors well known in the art may be used. Also, although the structural members are shown connected to open structural member  10  which has a minor flange, major flange and divergent portion, connection to this type of structural member is not necessary. Rather, structural members  112  may be connected to any structural member known in the art having a substantially planar surface.  
         [0059]    The embodiment described above provides a number of advantages including efficient roll forming for chord production; provision of a strengthened and stiffer open section member chord with proper orientation of the major flange outermost; the ability to treat or coat the entire chord or composite beam or truss having open sections prior to use; compact truss stacking with chords being proud of truss web members thereby minimizing damage to the truss members during transportation and reducing transport and storage costs; the ability of the chords to overlap for interconnection while maintaining the overlapped chords in line one above the other for symmetry of the truss and to be easily fastened together at terminations.  
         [0060]    It will of course be realized that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth.