AU783053B2 - Structural framework, method for forming the framework and webs therefor - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant: MITEK HOLDINGS, INC.

Invention Title: STRUCTURAL FRAMEWORK, METHOD OF FORMING THE FRAMEWORK AND WEBS THEREFOR The following statement is a'full description of this invention, including the best method of performing it known to us: I i1 2 STRUCTURAL FRAMEWORK, METHOD OF FORMING THE FRAMEWORK AND WEBS THEREFOR Field of the Invention This invention relates to a structural framework, a method of forming a framework and webs therefor and, in particular, but not exclusively, to a structural framework in the form of a building truss including at least one top chord arranged obliquely to a generally horizontal bottom chord. The invention also relates to a pedestal for use in the manufacture of such frameworks.

Background of the Invention Our International Patent Application No. PCT/USOO/23367 discloses a structural framework in the form of a building truss which includes metal webs which extend between the top chords of the truss and the bottom chord of the truss.

The reinforcing webs in one form as disclosed in the above International application comprise tubular members of circular cross section which have deformed ends to provide flattened tabs which extend parallel to the longitudinal axis of the web. The tabs are bent during installation so as to lie flush with a surface of the chords to which the reinforcing members are to be connected. In conventional wooden trusses, adjacent reinforcing webs are arranged so that the webs contact one another. Indeed, in the formation of conventional trusses which have wooden reinforcing webs, the webs contact one another so that compressive and tensile loads applied to the truss are transferred from the chords and absorbed by the truss. In general practice the wooden web which is to undergo compression contacts the adjacent web which undergoes tension and the two webs are connected to a chord of the truss by a common connector plate.

In the formation of conventional structural frameworks, in particular, wooden trusses which have oblique top chords \\me lbtiles\home$\mbourke\Keep\Speci\Mitek Prov-Structural framework.doc 20/05.'02 3 and a generally horizontal bottom chord, the chords are laid out on pedestals which are positioned to define the general configuration of the truss. The chords can be held in place by clamps which abut outer surfaces of the chords. Reinforcing webs cut from wood are connected to the chords at predetermined locations and the prescribed length of the wooden reinforcing webs and their proper installation in the truss define the final configuration of the truss. In particular, the wooden members are generally cut to have an end face at each end and the end face of a web is positioned at a predetermined location and secured to a chord. The other end face is then pulled into engagement with an opposed chord until the end face sits flush with the opposed chord thereby indicating that the web is in position. This may require some movement of the chord so that the chord does sit flush with the end of the web. Such movement may be necessary to take a bow out of the chord. When the end is positioned flush with the chord, the end is secured in position. Thus, the final exact shape of the framework and, in particular, the chords of the framework is provided by the installation of the reinforcing webs in the framework.

In the formation of structural frameworks in which metal webs are used, the manner of connecting the metal webs, as described in the above International application, does not allow the installation of the webs themselves to define the configuration of the truss.

Furtherstill, in conventional frameworks which have wooden webs, the webs are laid out and secured in order because of the need to abut adjacent webs together. This therefore requires a workman to work in a particular sequence and the workman does not have the luxury of installing any particular web at any particular time.

H:\LuiSa\Keep\Speci\Mitek Prov-Structural framevork.doc 21/07/01 4 Summary of the Invention The object of the invention is to provide improvements to the structural frameworks and their method of manufacture disclosed in the above International application and also to the conventional wooden trusses.

The invention in a first aspect provides a method of forming a structural member having at least one top chord and at least one bottom chord, comprising the steps of: defining a theoretical connection point on at least one of the chords which provides structural integrity of the framework; connecting a metal web to the bottom chord and to the top chord so that the web is connected to the said one of the bottom chord or the top chord at a web connection point, which provides the required structural integrity, spaced from the theoretical connection point.

The formation of the structural framework with webs connecting the bottom chord and spaced from the theoretical connection point by a predetermined distance, enables greater flexibility in the selection of metal webs because adjacent webs do not have to be, and in fact are not, in actual physical contact with one another. Thus, 25 webs from a stock set of web lengths are more easily selected for use in the truss and more easily assembled in the truss because of the ability to space the connection points of the webs from a theoretical connection point by a predetermined distance.

"Preferably the method includes connecting a plurality of webs between the top chord and bottom chord so that the webs are inclined with respect to the chords and define pairs of webs which have a first end which are closer to one another than a second end of the webs of each pair, and wherein the said first ends are both connected to one of the chords at web connection points which are spaced H:\Luisal\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 f 5 apart from the theoretical connection point with the theoretical connection point being between the web connection points of the first ends of the webs.

Preferably the step of connecting the webs at the web connection points comprises spacing the web connection points apart from the theoretical connection point by a predetermined distance.

Preferably the step of spacing the web connection points apart by the predetermined distance comprise connecting the chords to the bottom truss within a predetermined distance range from the theoretical connection point but not outside the predetermined distance range.

Preferably the method includes the step of providing support means on which the chords are supported and the pedestals having markings which define the predetermined distance range in which the reinforcing webs can be connected to the web.

Preferably the method includes the step of providing the reinforcing web with tabs which are bent with respect to the longitudinal axis of the web at an oblique angle with respect to the longitudinal axis of the web, locating a tab against a surface of one of the chords and securing the tab to the chord, manually pulling the web so as to bring the tab at the other end of the web into engagement with another of the chords and to cause the said tabs to further bend so as to sit flush with the chords, and securing the other of the tabs in position.

Preferably the step of securing the webs includes providing temporary connection means on at least the said other tab so that when the said other tab is pulled into engagement with the other chord, the ancillary connection means temporarily connects and holds the reinforcing web H:\Luisa\Keep\Speci\mitek Prov-Sructural framework.doc 27/01/01 6 in position to facilitate final securement of the other said tab to the other said chord.

Preferably the step of providing ancillary connection means comprises providing a barb on the web which engages and penetrates the chord to temporarily locate and hold the web in position.

Preferably the barb is formed by bursting a hole through the tab, or forming a tooth on the tab adjacent an edge portion of the tab.

Preferably the support means comprises at least one pedestal. However, in other embodiments the support means could comprise a support table or platform with moveable support elements.

The invention may also be said to reside in a method of forming a structural framework having at least one top chord and at least one bottom chord, comprising the steps of: providing support means for supporting the chords of a framework, with the support means including markings which define connection regions, which include theoretical .i 25 connection points, at which ends of reinforcing webs can be connected to the chords of the framework; laying the at least one top chord and the bottom chord on the support means; and connecting the reinforcing webs between the at 30 least one top chord of the framework and the bottom chord of the framework by securing the ends of the reinforcing webs within the connection regions marked on the support means.

Preferably the step of providing support means comprises the step of moving the support means to predetermined positions so as to define the connection regions of the H:\Luisa\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 h 7 reinforcing webs to the chords when the chords are laid on the support means.

Preferably the step of providing the markings includes providing a marking which defines a theoretical connection point, and a marking which defines, with a theoretical connection point, the connection region.

Preferably the step of providing the markings further includes providing a marking which defines a preferred connection point between the theoretical connection point and the marking which defines the connection region with the theoretical connection point.

Preferably the support means comprises at least one pedestal. However, in other embodiments the support means could comprise a support table or platform with moveable support elements.

Preferably the method includes the step of providing the reinforcing web with tabs which are bent with respect to the longitudinal axis of the web at an oblique angle with respect to the longitudinal axis of the web, locating a tab against a surface of one of the chords and securing the tab to the chord, manually pulling the web so as to bring the tab at the other end of the web into engagement with another of the chords and to cause the said tabs to further bend so as to sit flush with the chords, and securing the other of the tabs in position.

Preferably the step of securing the webs includes providing temporary connection means on at least the said other tab so that when the said other tab is pulled into engagement with the other chord, the ancillary connection means temporarily connects and holds the reinforcing web in position to facilitate final securement of the other said tab to the other said chord.

H:\Luisa\ieep\Speci\Mitek Prov-Structural frwmework.doc 21/07/01 -8 Preferably the step of providing ancillary connection means comprises providing a barb on the web which engages and penetrates the chord to temporarily locate the web in position.

Preferably the barb is formed by bursting a hole through the tab, or forming a tooth on the tab adjacent an edge portion of the tab.

The invention may also be said to reside in a support member for supporting a chord of a structural framework, the support member comprising: an upper support region for supporting the chord; and markings on the upper support portion for defining at least one connection region, which includes a theoretical connection point, in which a reinforcing web of the structural framework can be connected to a chord of the framework when the chord is supported on the support member.

Preferably the markings include a first marking which shows a theoretical connection point and a second marking which shows a desired connection point.

Preferably the markings further include a third marking which defines, with the first marking, the connection region.

Preferably the support member comprises a pedestal for coupling with a rail member on which the pedestal can move from one place to another.

:go• The invention, in a further aspect, may be said to reside in a structural framework comprising: at least one top chord; at least one bottom chord; H:\Luisal\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 9 at least two adjacent metal webs extending between the top chord and the bottom chord, the adjacent webs each having a respective end connected to one of the chords, to provide the required structural integrity, so that the respective ends are spaced apart from one another, and with the end of one of the webs being connected to the chord a first distance spaced from a theoretical connection point and the end of the other web being connected to the chord a second distance spaced from the theoretical connection point, the theoretical connection point being between the two ends of the respective webs which are connected to the chord, and so that the adjacent webs do not abut one another.

This aspect of the invention provides considerably greater freedom in connecting the webs to the chords because the webs do not need to abut one another, but rather are spaced on either side of a theoretical connection point which is used in analysis of the framework design to determine where webs should be located in order to provide the required structural integrity of the framework. Since

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the webs do not abut one another, the webs can therefore be laid out in any particular order and can be connected in any sequence. This provides a workman or workmen with 25 greater freedom in connecting ends of the chords and therefore provides for the possibility of greater productivity in that frameworks can be assembled much quicker than in the past.

Preferably the first distance is the same as the second S. distance.

•Preferably the ends of the webs are connected to the chord *at predetermined web connection points spaced from the theoretical point.

Preferably the webs are connection to the chords within a connection range which includes the preferred web H:\Luisal\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 10 connection point for each of the respective webs.

Preferably the webs include tabs which sit flush with a surface of the chord and the tabs are connected to the chord by screws which pass through a hole in the tab.

Preferably the hole defines the connection point of the respective webs to the chord.

Brief Description of the Drawings Preferred embodiments of the invention will be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a side view of a reinforcing web according to one embodiment of the invention; Figure 2 is a plan view of one end of the web of Figure 1; Figure 2A is an enlarged view of part of the web

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THE NEXT PAGE IS PAGE 16 H:\Luisa\Keep\Speci\Mitek Prov-Structural framework.doc 18/04/05 16 of Figures 1 and 2; Figure 3 is a side view of a reinforcing web according to a second embodiment of the invention; Figure 4 is a plan view of one end of the web of Figure 3; Figure 4A is an enlarged view of part of the web of Figures 3 and 4; Figure 4B is a side view of the part of the web of Figure 4A; Figure 5 is a view of an end of a reinforcing web according to a third embodiment of the invention; Figure 6 is a cross-sectional view along the line AA of Figure Figure 7 is a cross-sectional view along the line BB of Figure Figure 8 is a cross-sectional view along the line CC of Figure Figure 9 shows a pedestal layout for manufacturing a structural framework in the form of a building truss having inclined upper chords and a horizontal lower chord joining the upper chords; Figure 10 is a plan view of a pedestal used in the embodiment of Figure 9; Figure 11 is a plan view of another pedestal used in the embodiment of Figure 9; Figure 12 is a view of a still further pedestal; Figure 13 is a view of a still further pedestal used in the embodiment of Figure 9; Figure 14 is a view similar to Figure 9 but with the chords laid out to form a building truss; Figure 14A is a plan view of a pedestal including a clamp of the preferred embodiment; Figure 14B is a view along the line Y-Y of Figure 14A; Figure 15 is a view showing the application of clamping force to the chords of Figure 14; Figure 16 shows the formed truss including H:\Lisa\Keep\Speci\Mitek Prov-gtructural framework.doc 27/07/01 17 reinforcing webs; Figure 17, Figure 18, Figure 19 and Figure 20 are a sequence of drawings showing installation of a reinforcing web according to the preferred embodiment of the invention; Figure 21 is a view of a web held temporarily against a chord awaiting final securement; and Figure 22 is a view of webs in final secured position.

Description of the Preferred Embodiments Figure 1 shows a reinforcing web 10 according to the first embodiment of the invention. The web 10 has a web body 12 and tabs 14 at each end. The tabs 14 are connected to the body 12 by a transition section 18, which is a deformation created in order to flatten ends of the tubular member from which the reinforcing web 10 is formed, to provide the tabs 14. Our co-pending International application PCT/US00/23367 discloses, in more detail the manner in which the tabs 14 and deformation 18 is formed and the contents of this International application are incorporated into this specification by this reference.

In this embodiment the body 12 is formed from a complete tube of generally circular transverse cross section.

The tabs 14 are bent at a predetermined oblique angle with respect to the longitudinal axis X of the web 10 of, for example, 250 to 500 and most preferably about 300 as shown by arrow a in Figure 1. As is clearly seen in Figure 1, one of the tabs 14 is bent in one direction with respect to the axis X and the other tab 14 is bent in the opposite direction with respect to the axis X so that each are inclined towards a position the tabs will take up when the web 10 is installed in a building truss as will be described in more detail hereinafter. The pre-bending of the tabs 14 produces an initial bend in the direction the \\melbfiles\homeS \mbourke\Keep\Seci \Mitek Prov-Structural frameworkdoc 20/05,02 18 tabs will move upon installation of the web to take up their final orientation with respect to the web body 12.

This tends to ensure that the radius of curvature between the tabs 14 and the transition section 18 after the tabs 14 are bent to their final orientation, will be as small as possible so that the tabs 14 sit flush and tightly against surfaces of the respective chords between which the web 10 is located.

As best shown in Figure 2, the tabs 14 include a hole which will receive a screw for permanently securing the tabs 14 to the chords of the truss.

The tabs 14 are also formed with a burst hole 24 shown in detail in Figure 2A which is punched through the tabs 14 so as to deform metal from the tabs which produces barbs 26 which project transversely with respect to the tabs 14.

The barbs 26 form ancillary connections for temporarily holding the web 10 in place during installation of the web 10 in the truss as will also be described in more detail hereinafter.

Figure 3 shows a second embodiment of the invention in which like reference numerals indicate like parts of those described with reference to Figures 1 and 2. In this embodiment of the invention, rather than form the barbs from a burst hole in the tab 14, the barbs are in the form of teeth 28 (best shown in Figures 4A and 4B) which are cut from side portions of the tab 14 before bending of the tab 14 so that the cut portions which form the teeth 28 remain parallel with the longitudinal axis X of the web body 12.

In still further embodiments, not shown, the barbs could be formed by forming a cut in the tab 14 at the outermost end of the tab 14 and folding portions of the tab 14 adjacent the cut downwardly so as to create teeth \\melbf i es\home$ borke \Keep\Speci \Mi tk Prov-Strctu.ra framework.doc 20/05/02 19 extending transversely with respect to the tabs 14.

Figures 5 to 8 show a still further embodiment of the invention. In this embodiment the web 10 is formed from a rolled blank and without joining free edges 11 and 13 of the blank together so that a central slot 30 extends along the length of the web body 12 from one end of the web body to the other. The free edges 11 and 13 may have inwardly extending flanges 13A which provide greater structural integrity to the web body 12. The flanges 13A can be formed during rolling of the web body 12 by first rolling the flanges 13A at the free edges of the blank from which the web body 12 is formed and then rolling the blank into the tubular shape having the circular cross-section as shown in Figure 6.

Ends of the rolled blank are then deformed in the same manner as described with reference to the above-mentioned International application so as to form a transition section 18 and a tab 14. In this embodiment the tab 14 is provided with the hole 20 and also the burst hole 26, although rather than the burst hole 26, teeth 28 could be formed as in the embodiment of Figures 3 and 4.

The deformation of the ends of the rolled tube 12 is such that a valley 36 is formed between a pair of ridges 38 with the valley including a slit 40 which is an extension of the slot 30. The valley 36 is formed by pressing free edges 11 and 13 in the transition region 18 inwardly and downwardly so that they spread in central region 41 of the slit 40 as shown by cross section B and the slit 40 tapers inwardly from central region 41 to one end 43 which merges into the slot 30 and to other end 45 which is adjacent tab 14. The pressing of the free edges 11 and 13 inwardly to form the slit 36 also adds to the structural integrity of the web 10. The opposite side of the transition section 18 is also formed with a valley 46 which is located \\melbfi es\home\bourke\Keep\Speci\Mi ek Prov-Structural framework.doc 20/05/02 20 between the pair of ridges 48. As in the above-mentioned International application, the tab 14 can be trimmed so as to maintain the width of the tab 14 generally within the confines of the body 12 so that the tab 14 is substantially no wider than the body 12.

Figure 9 shows a pedestal layout for forming a truss using metal webs of the type described with reference to the embodiments of Figures 1 to 8. Pedestals 50 are arranged on a base rail 54 and outrigger arms 55. The outrigger arms 55 can be moved into various positions and the pedestals 50 moved on the outrigger arms and also on the base rail 54 to position the pedestals 50 at required places to support chords (not shown in Figure 9) of a building truss. The jigging system 52 can be of conventional design, or of the type disclosed- in our Australian Patent Application No. 18313/01, the contents of which are incorporated into this specification by this reference. A gantry press system 61 is provided for pressing nail plates into the wooden chords so as to secure the chords together in a manner which is also well known and therefore will not be described in any further detail. The pedestals 50 are generally of known design and therefore will not be described in further detail except as is necessary to explain differences between the conventional form of the pedestals 50 and those of the preferred embodiments of the present invention.

Figure 10 is a plan view of a pedestal commonly called an apex box which is arranged on outrigger arm 55' in Figure 9. The pedestal 52 of Figure 10 has an upper support platform 54 and an abutment rail 56. A clamp 58 is provided for providing a clamping force to an inner surface of a chord as will be described in more detail hereinafter or, in other words, a clamping force that is directed towards the outside of the truss profile, in the direction of arrow F, so as to push the chord supported by \\melbfiles\home$\ Luisa\Keep\Speci\Mitek Prov-Structural framework.doc 7/10/03 21 the pedestal 50 of Figure 10 firmly into abutment with the abutment rail 56 and hold the chord fixed in a prescribed position. The abutment rail 56 of the apex box type pedestal 50 shown in Figure 10 has a v-shaped notch 59 in which ends of the chords which define the apex of the truss are located. When the clamp 58 is moved into clamping position, the ends of the chords are pushed into the v-shaped notch 59 and abut one another. A second clamp 58' is provided on the other side of the platform 54 for clamping the other chord which will define the apex of the truss.

The support platform 54 of the pedestal 50 is provided with a number of markings which show regions in which reinforcing webs of the type described with reference to Figures 1 to 8 can be connected to the chord supported on the support platform 54. The markings include a first central marking 60, a pair of second markings 62 spaced, for example, 50mm from the line 60, and a pair of third markings 64, each spaced 100mm from the line 60. The markings 60, 62 and 64 may be colour-coded and simply provided by drawn lines or lines formed from tape on the platform 54. The pedestal 50 of Figure 10 can be used as a pedestal for locating the apex of the truss or, it can be used along the length of one of the upper chords in which case it merely performs the function of a top chord box. If the pedestal is being used as an apex box to define the apex of the chord, the lines 64 are used to define the web connection point of the webs adjacent the apex. These webs are usually the first connection made so that the webs, which will be connected adjacent the apex of the truss, are connected with the respective holes of the respective tabs 14 being aligned with the line 64.

If the apex box is simply used as a top chord box for forming a web connection at a place other than the apex, the lines 62 are used to define the ideal or preferred location point for aligning the holes 20 of the webs to \\melbfies\homeS\ntourke\eep\Speci\itek Prov-Structural framework.doc 22/05/02 22 connect the web to the chord. The lines 64 define a distance range with the line 60 in which the webs can be connected. Thus, the lines 62 show the location of a preferred web connection point of a reinforcing web with the chord and the lines 64 with the lines 60 define a connection region in which,. depending on the length of the web selected from a stock set of lengths, the web can be connected to the respective chords so as to ensure the structural integrity of the formed truss.

The marking 60 defines a theoretical connection point which is used in the analysis and calculation of a web layout for a particular truss which will provide the truss with the required structural integrity in order to perform the intended function of the truss. Typically, a number of theoretical connection points will be defined on the chords of the truss to which theoretical webs could be connected to provide that structural integrity. When a truss is designed, various truss layouts which include the chords and the webs are produced in software so that the location of the webs relative to the chords is determined.

Generally the software may run through various routines and place webs in different positions in order to determine a required layout which provides the structural integrity of the truss. Once this has been done, theoretical connection points are determined and are then fixed. As explained above, these theoretical connection points are defined by the markings 60 and when the pedestals are moved under the control of the software or otherwise, those points 60 are located relative to the chords to define the theoretical connection points. The theoretical connection points are not the points at which the webs will actually be connected, but merely theoretical points which provide the required structural analysis. The actual preferred connection points are spaced on either side of the theoretical connection point by a distance of, for example, 50mm which is given by the \\melbfiles\homeS\mbourke\Keep\peci\i ek Prov-Structura1 framework.doc 20/05/02 23 markings 62 or at least within the range defined by the markings 60 and 64.

In conventional truss analysis and design, theoretical connection points are also determined but those theoretical connection points are moved to provide the actual connection points at which the two adjacent webs are fixed. Because the two adjacent webs must be fixed at that point, less freedom is provided in the selection of webs from a stock set of lengths whereas, with the present invention, because the webs are actually connected a distance from the theoretical point, much greater flexibility is provided.

Thus, in the preferred embodiment of the invention, the metal webs of the preferred embodiment are connected to the chords a distance spaced from the theoretical connection point which is determined in analysis to set out a web layout for the truss which will provide the required structural integrity. Preferred connection points a predetermined distance from the theoretical connection point and on each side of the connection point are then used to connect adjacent web ends so as to provide the required structural integrity.

Thus, in the preferred embodiment of the invention, rather than connect the webs at the theoretical connection point, the webs are connected so that adjacent webs are spaced apart by a distance preferably equal to the distance between the marking 62. However, the adjacent webs could be connected so that one web is connected to the chord anywhere in the connection region between the markings and 64 and the other web is connected anywhere between the marking 60 and the other of the markings 64.

Figure 11 shows a pedestal 50 in the form of a universal box which can be provided on the outrigger arms 55 other %melb-f \hom$ \mbourke\Keep\ Spe c i Prov-Structural framework.doc 22/05/02 24 than the arm 55'. This box is basically the same as the box of Figure 10 except it does not have a notch 59 in the abutment bar 56 because the abutment bar 56 will abut a straight edge of one of the inclined upper chords of the truss. The pedestal 50 of Figure 11 includes clamps 58 which are identical to the clamps of the pedestal 50 shown in Figure 10. This box also includes markings which comprise a first marking 60 which defines a theoretical connection point for a reinforcing web, a second pair of markings 62 which define preferred connection points which are spaced from the theoretical point by the distance of and a third set of markings 64 which are spaced from the line 60 by 100mm, and which, with the markings define a connection region in which a reinforcing web can be connected to a chord so as to ensure the structural integrity of the truss.

Figure 12 shows a universal box which has the same marking with the same spacings as the box of Figure 11. This box is preferably used on the rail 54 and has an abutment rail 56 and a clamp 58 which will provide a clamping force in the direction of arrow F to clamp an inner surface of the lower chord or, in other words, to provide a clamping force directed outwardly of the truss so as to push the lower chord hard against the abutment rail 56.

Figure 13 shows a splice box which is the box 50'' on rail 54 in Figure 9 and which can be positioned where two pieces of timber which are to form the lower web abut one another and which are joined by a nail plate so as to form the lower chord of the truss. This box can also be used as a pedestal which defines a connection point for a web as well as a splice between pieces of timber which define a chord and therefore also has markings which are identical to the markings of Figures 10, 11 and 12 and clamps 58 which provide a clamping force in the direction of arrow F in Figure 13.

\\melbfiles\home\ borke\Kep\peci \itek Prov-Structural framework.doc 22/05/02 25 Figure 14 shows chords 70 and 72 which are inclined with respect to one another and form the upper chords of the truss and bottom chord 74 positioned in place on pedestals 50. The chords are preferably made from wood but could also be made from metal. It should be noted that not all the pedestals 50 in the system need be used in order to support the chords 70, 72 and 74 and form the truss. As is conventional, pedestals in the form of heel boxes 59 are located at the ends of the truss where the upper chords 70 and 72 join with the lower chord 74. These pedestals are completely conventional in nature and need not be marked because reinforcing webs will not be connected to the parts of the chords supported by these pedestals.

The chords 70, 72 and 74 are connected together by nail plates which are pressed into the chords 70, 72 and 74 in a conventional manner which therefore need not be described.

Figures 14A and 14B show the clamp 58 which is used on the pedestals of Figures 10 to 13. As is apparent from Figures 10 to 13, the pedestal shown in Figure 10 shows two clamps, the pedestal in Figure 11 a single clamp, the pedestal in Figure 12 a single clamp and the pedestal in Figure 13 two clamps. Only one of the clamps is shown in Figure 14A but the other, if the pedestal includes two clamps, is identical.

The clamp 58 comprises a channel section 100 which contains a pneumatic or hydraulic ram 102. The ram 102 has a ram arm 104 which is connected to a clamp element 106 in the form of a cylinder which extends up above the channel 100. The cylinder 106 can be connected with a block 108 to facilitate sliding movement of the cylinder 106 within the channel 100 when the ram arm 104 is \\melbfiles\home\Luisa\Keep\Speci\Mitek Prov-Structural framework.doc 7/10/03 26 extended to provide a clamping force. Fluid to power the clamp 58 may be supplied by a line 110.

A sliding plate 112 is mounted on the channel 100 and is coupled to the cylinder 102 by a screw 114 to secure the rear of the cylinder within the channel 100. The plate 112 has a lower T-shaped plate 116 which is connected to the plate 112 by a screw 118 so that when the screw 118 is tightened, the plates 112 and 116 are pulled together so as to clamp the plate 112 to in-turned flanges 120 of the channel 110. By loosening the screw 118, the plate 112 can be moved along the length of the channel 100 to position the ram 102 in the required position depending on timber size.

Figure 15 is a view similar to Figure 14 but including the arrows F which show the clamping force provided by the clamps 58 which clamp against inner surfaces of the chords 72 and 74 respectively or, in other words, provide a clamping force which is directed outwardly of the truss and which push the chords 70, 72 and 74 hard against the abutment rails 56 of the pedestals 52.

The clamps 58 together with the abutments 56 define the geometrical shape of the truss formed from the chords 72 and 74 in its final orientation before location of the reinforcing webs 10 within the chords 70, 72 and 74 to complete the truss.

Figure 16 is a view similar to Figure 15 showing the reinforcing webs 10 secured in position so as to complete the truss.

The pedestals 50 are positioned in a manner known per se usually under the control of a computer program so as to support the chord 70 in the vicinity of connection points \\melb files\home$\Luisa\Keep\Speci\Mitek Prov-Structural framework.doc 7/10/03

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27 at which the reinforcing webs 10 will connect to the chords 70, 72 and 74. After the pedestals are located in place, the chords are located on the pedestals and are clamped in place by the clamps 58 and the abutment rails 56 to define the geometry of the truss before the webs are connected in place.

Figures 17 to 20 explain the connection of the reinforcing webs 10 and, in particular, the connection of the reinforcing web 10' in Figure 16. In general, the webs are laid out and supported on the pedestals 52 as shown in Figure 16 before any of the webs 10 are secured in place.

The web marked 10'' in Figure 16 is usually connected in place first. The pedestals 52 are moved into position so that the mark 60 of the pedestals, which defines a theoretical connection point of webs 10' to the chords 72 and 74, is located at those theoretical connection points. The web 10'' is secured in place in the same manner as the web 10' and this securement process will be described in detail with reference to Figures 17 to which applies to the web 10'. The web 10' is first positioned so that the tab 14 is located in place so that the hole 20 through which the screw (not shown) will pass is in alignment with the mark 62 which defines the preferred connection point which is spaced a predetermined distance from the connection point 60. The pre-bend of the tab 14 facilitates general support of the reinforcing web 10 by the pedestals 52 shown in Figure 17 because the pre-bend will tend to orient the web 10 generally in the position shown in Figure 17 when the bend 14 sits generally flush with the surface 74a of the chord 74. A screw can then be easily driven through the hole 20 in the tab 14 so as to secure the tab 14 to the surface 74a of the chord 74. This securement is shown in Figure 18 and it can be seen in Figure 18 that the web 10 is inclined with respect to the chord 74 and generally sits on an edge of the box 52 because of the pre-bend in the tab 14. The \\melb~files\home\Luisa\Keep\Speci\Mite k Prov-Structural fra-ework.doc 7/10/03

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28 spiral arrow in Figure 18 represents installation of the screw (not shown) through the hole 20 to connect the tab 14 to the chord 74.

As shown by Figure 19, the web 10 is then gripped by a workman (not shown) and pulled in the direction of arrow B so as to pull the other tab labelled 14'' in Figure 18 flush against the surface 70a of the chord 70. This movement bends the web body 12 of the web 10 with respect to the fastened tab 14 so the body 12 takes up its final orientation with respect to the tab 14. The pre-bend of the tab 14 ensures that the radius of curvature of the bend between the tab 14 and the transition 18 is as small as possible so that the tab 14 sits flush and tightly against the surface 74a of the chord 74. The workman pulls the tab 10 into position so that the hole in the tab 14'' falls within the limits defined by the mark 60 and the mark 64 in Figure 19. When the tab is pulled into this position, the workman knows that the tab 14'' is located in the correct position. Most preferably the hole will be on the preferred mark 62 but depending on the size of the web 10 which is selected and accuracy of positioning of the pedestal 50 and the contour of the chord 70, the hole 20 may not be exactly on the mark 62.

However, provided that the hole 20 falls within the region between the mark 60 and the mark 64, the workman will know that the web 10 is properly positioned.

When the web 10 is pulled into the position shown in Figure 19, the barbs 26 or 28 which are formed on the tab as described with reference to Figures 1 to 4, will bite into the surface 70a, as shown in Figure 21, and when the workman releases the barb 10, the embedding of the barbs into the surface 70a will prevent the chord 10 from moving or sliding on the surface 70a in a direction opposite arrow B. Thus, once the web 10 has been pulled into position the workman knows that the web will hold in \\melbfi es\homeS\Luisa\Keep\Speci\Mitek Prov-Structural framework.doc 7/10/03 29 that position because of the embedding of the barbs 26 or 28 into the surface 70a and the workman then has two free hands available to him to use a drill or other work piece in order to screw a screw through the hole 20 in the tab 14'' and securely fasten the tab 14'' to the surface of the chord 70. As the workman pulls the web 10 into the position shown in Figure 19, the tab 14'' will bend further from the original position shown in Figures 1 to 4 and into its final orientation with respect to the web Once again, the slight pre-bend will ensure that the radius of curvature between the transition region 18 of the tab 14'' is as small as possible so that the tab 14'' sits flush and tightly against the surface 70a. Figure illustrates by the spiral arrow shown in Figure 20 the securement of the tab 14'' in place.

The securing of the web 10 and, in particular, the securement of the screw which will locate the tab 14' to the web 70 as shown in Figure 20, will have the tendency to pull the web 70 inwardly in the direction of arrow C in Figure 20 towards the chord 74. The tendency of the chord to move in the direction of arrow C, or in other words, for the chord 70 and 74 to pull together is prevented by the clamps 58 which provide a clamping force on the inner surfaces 70a and 74a of the chords 70 and 74, or in other words, a clamping force directly outwardly of the truss.

Thus, the clamping of the inner surface which defines the final geometry of the truss prevents the chords 70 and 74 from moving during installation of the webs 10 which may otherwise occur, particularly if the holes 20 in the tabs 14 do not align exactly with the preferred connection points shown by the mark 62 on the pedestals 52.

As is apparent from a consideration of Figures 16 to when the webs 10 are secured in place, the holes 20 in the tabs 14 are spaced apart from one another a predetermined distance from the theoretical connection point \\melbfi es\home\mbourke\Keep\SpeCi\Mitek Prov-Sructcral fraework.doc 20/05/02 30 preferably by a distance given by the preferred connection point 64 but, in any event, within a region defined by the markings 60 and 64. The tabs 14 are also spaced apart and do not abut one another. The spaced apart connection of the webs 10 in this manner provides greater flexibility in the selection of webs 10 from a stock set of web lengths and therefore the formation of trusses using those webs.

Figure 22 shows an adjacent pair of webs 10 secured to one of the chords, such as the chord 70. As is apparent from consideration of Figure 22, the web connection points which are defined by the holes 20 through which screws S are driven so as to secure the tabs 14 to the chord are spaced apart from the theoretical connection point shown in dotted lines. The screws and holes 20 are in alignment with the preferred connection point 62, and obviously within the range defined by the lines 64. The webs 10 shown in Figure 22 define a pair of webs which have ends which are shown in Figure 22 which are closest together and secured in the above manner. The other ends of the webs 10 shown in Figure 22 are secured to a top chord or top chords and with another web, not shown, will define another pair of webs which have ends close together and which are connected in the same manner as described with reference to Figure 22.

With reference to the use of the word(s) "comprise" or "comprises" or "comprising" in the foregoing description and/or in the following claims, we note that unless the context requires otherwise, those words are used on the basis and clear understanding that they are to be interpreted inclusively, rather than exclusively, and that we intend each of those words to be so interpreted in construing the foregoing description and/or the following claims.

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Claims (26)

1. A method of forming a structural member having at least one top chord and at least one bottom chord, comprising the steps of: defining a theoretical connection point on at least one of the chords which provides structural integrity of the framework; connecting a metal web to the bottom chord and to the top chord so that the web is connected to the said one of the bottom chord or the top chord at a web connection point, which provides the required structural integrity, spaced from the theoretical connection point.

2. The method of claim 1 wherein the method includes connecting a plurality of webs between the top chord and bottom chord so that the webs are inclined with respect to the chords and define pairs of webs which have a first end which are closer to one another than a second end of the webs of each pair, and wherein the said first ends are both connected to one of the chords at web connection points which are spaced apart from the theoretical connection point with the theoretical connection point 'being between the web connection points of the first ends of the webs. 25

3. The method of claim 2 wherein the step of connecting the webs at the web connection points comprises spacing the web connection points apart from the theoretical connection point by a predetermined distance.

4. The method of claim 3 wherein the step of spacing 30 the web connection points apart by the predetermined So. distance comprise connecting the chords to the bottom truss within a predetermined distance range from the theoretical connection point but not outside the predetermined distance range.

5. The method of claim 1 wherein the method includes the step of providing support means on which the chords are supported and the support means having markings which H:\Luisal\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 32 define the predetermined distance range in which the reinforcing webs can be connected to the web.

6. The method of claim 1 wherein the method includes the step of providing the reinforcing web with tabs which are bent with respect to the longitudinal axis of the web at an oblique angle with respect to the longitudinal axis of the web, locating a tab against a surface of one of the chords and securing the tab to the chord, manually pulling the web so as to bring the tab at the other end of the web into engagement with another of the chords and to cause the said tabs to further bend so as to sit flush with the chords, and securing the other of the tabs in position.

7. The method of claim 1 wherein the step of securing the webs includes providing temporary connection means on at least the said other tab so that when the said other tab is pulled into engagement with the other chord, the ancillary connection means temporarily connects and holds the reinforcing web in position to facilitate final securement of the other said tab to the other said chord.

8. The method of claim 7 wherein the step of providing ancillary connection means comprises providing a barb on the web which engages and penetrates the chord to temporarily locate and hold the web in position.

9. The method of claim 8 wherein the barb is formed by bursting a hole through the tab, or forming a tooth on the tab adjacent an edge portion of the tab.

A method of forming a structural framework having at least one top chord and at least one bottom chord, comprising the steps of: 30 providing support means for supporting the chords of a framework, with the support means including markings which define connection regions, which include theoretical connection points, at which ends of reinforcing webs can be connected to the chords of the framework; laying the at least one top chord and the bottom chord on the support means; and connecting the reinforcing webs between the at H:\Luisal\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 33 least one top chord of the framework and the bottom chord of the framework by securing the ends of the reinforcing webs within the connection regions marked on the support means.

11. The method of claim 10 wherein the step of providing support means comprises the step of moving the support means to predetermined positions so as to define the connection regions of the reinforcing webs to the chords when the chords are laid on the support means.

12. The method of claim 10 wherein the step of providing the markings includes providing a marking which defines a theoretical connection point, and a marking which defines, with a theoretical connection point, the connection region.

13. The method of claim 12 wherein the step of providing the markings further includes providing a marking which defines a preferred connection point between the theoretical connection point and the marking which defines the connection region with the theoretical connection point.

14. The method of claim 10 wherein the method includes the step of providing the reinforcing web with tabs which are bent with respect to the longitudinal axis of the web at an oblique angle with respect to the 25 longitudinal axis of the web, locating a tab against a surface of one of the chords and securing the tab to the chord, manually pulling the web so as to bring the tab at the other end of the web into engagement with another of the chords and to cause the said tabs to further bend so 30 as to sit flush with the chords, and securing the other of the tabs in position.

The method of claim 10 wherein the step of securing the webs includes providing temporary connection means on at least the said other tab so that when the said other tab is pulled into engagement with the other chord, the ancillary connection means temporarily connects and holds the reinforcing web in position to facilitate final H:\Luisal\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 34 securement of the other said tab to the other said chord.

16. The method of claim 15 wherein the step of providing ancillary connection means comprises providing a barb on the web which engages and penetrates the chord to temporarily locate the web in position.

17. The method of claim 16 wherein the barb is formed by bursting a hole through the tab, or forming a tooth on the tab adjacent of the edge portion of the tab.

18. A support member for supporting a chord of a structural framework, the support member comprising: an upper support region for supporting the chord; and markings on the upper support portion for defining at least one connection region, which includes a theoretical connection point, in which a reinforcing web of the structural framework can be connected to a chord of the framework when the chord is supported on the support member.

19. The support member of claim 18 wherein the markings include a first marking which shows a theoretical connection point and a second marking which shows a desired connection point.

20. The support member of claim 19 wherein the markings further include a third marking which defines, with the first marking, the connection region.

21. A structural framework comprising: at least one top chord; at least one bottom chord; at least two adjacent metal webs extending between the top chord and the bottom chord, the adjacent webs each having a respective end connected to one of the chords to provide the required structural integrity and so that the respective ends are spaced apart from one another, and with the end of one of the webs being connected to the chord a first distance spaced from a theoretical connection point and the end of the other web being connected to the chord a second distance spaced from H:\Luisa1\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05 35 the theoretical connection point, the theoretical connection point being between the two ends of the respective webs which are connected to the chord, and so that the adjacent webs do not abut one another.

22. The method of claim 21 wherein the first distance is the same as the second distance.

23. The method of claim 21 wherein the ends of the webs are connected to the chord at predetermined web connection points spaced from the theoretical point.

24. The method of claim 21 wherein the webs are connection to the chords within a connection range which includes the preferred web connection point for each of the respective webs.

The method of claim 21 wherein the webs include tabs which sit flush with a surface of the chord and the tabs are connected to the chord by screws which pass through a hole in the tab.

26. The method of claim 21 wherein the hole defines the connection point of the respective webs to the chord. Dated this 1st day of July 2005 MITEK HOLDINGS, INC. By their Patent Attorneys S 25 GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia *00 0-060 go* *ooo* H:\Luisal\Keep\Speci\Mitek Prov-Structural framework.doc 1/07/05