AU650913B2 - Pitched roof framing system and method of constructing same - Google Patents

Description

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AUSTRALIA

Patents Act 1990 0 9 1 7 COMPLETE SPECIFICATION For a Standard Patent

ORIGINAL

0 o o 0 o o o os o St 0 o 4 o ao TO BE COMPLETED BY APPLICANT Name of Applicant: DARYL ARTHUR POOLE Actual Inventor: DARYL ARTHUR POOLE Address for Service: 00 Cl 4 Cci WRAY ASSOCIATES, Primary Industry House, Terrace, Perth, Western Australia, 6000.

239 Adelaide Attorney code: WR c C r Invention Title: Constructing Same" C "Pitched -Roof Framing System and Method of C C C Details of Associated Provisional Application No: PK3062 The following statement is a full description of this invention, including the best method of performing it known to me:- 1 ll~ sa~-r~ C: 2 THIS INVENTION relates to a pitched roof framing system for mounting atop a house and to a method of constructing a pitched roof for a house.

A conventional pitched roof comprises a roof frame and cladding means whereby the roof frame acts as a supporting means for the cladding elements (most commonly clay tiles or metal decking) and as a load bearing means for live loads such as wind, earth movement etc, and point loads which may be exerted on the roof.

1 0 Most roof frames for pitched roofs include ridges, o downwardly angled hips, valleys and rafters, and usually o o some form of gable. In the commonly used "hip and gable" type pitched roof, there are basically two types of roof framing system employed.

The first type of roof framing system which is the older and more traditional system, is that of timber framing usually using hardwood. A typical roof construction using 2' i timber framing involves forming a ceiling platform comprising ceiling joists mounted upon wall plates which are secured to the internal and perimeter walls of the g house so that the ceiling joists span across opposing walls .of the house in a direction generally orthogonal to the intended ridge line of the roof. The ceiling joists are 1 required to perform a number of functions including: (i) f" 25 providing means by which the ceiling of the house may be suspended, (ii) forming ties to prevent the opposing walls of the house from splaying apart due to loads applied thereto from the roof, and (iii) providing mounting points for ceiling joist runners, struts and purlins which act to prevent rafters from excessive sagging due to the cladding weight and/or other loads acting upon the roof. i -3- After the platform is formed, a ridge board defining the ridge of the roof is suspended at an elevated location with respect to the platform so that the longitudinal extent thereof is parallel to the plane of the ceiling joists and generally perpendicular to the longitudinal extent of the ceiling joists. The ridge board is usually suspended in this manner by temporary supports affixed to the ceiling joists and/or ceiling joist runners mounted directly upon the ceiling joists in perpendicular relationship thereto.

A series of rafters are then attached to the ridge board at S°their upper ends at prescribed locations along the board o and to corresponding ceiling joists at their lower ends so o as to be downwardly angled from the ridge board in S° oppositely extending pairs. Moreover, each associated pair *0 15 of rafters is fixed to the ridge board at opposite sides thereof at the same position with respect to the longitudinal extent of the ridge board, and respectively connect to opposite ends of a common ceiling joist to form a two dimensional triangular truss disposed in a 20 substantially vertical plane. For additional strength, collar ties are generally attached across every third pair of rafters or so, about half way up in parallel spaced relationship to the common ceiling joists interconnecting the rafters. 25 In the case where long rafters are needed to span a whole house, purlins or underpurlins extending generally perpendicular across a series of rafters on one side and the other side of the ridge board are nailed edge on to the undersides of the rafters and are supported by props or struts attached at their lower ends to either a ceiling joist, a wall plate or a ceiling joist runner. The props are generally installed as near to upright as is possible but generally no flatter than 450 to the horizontal.

r 4 Depending on the plan layout of the house, hip and/or valley members may be required at intersecting planes of the roof defined by the rafters. These members are attached at their upper ends to the ridge board and at their lower ends to the wall plate. The lower ends of rafters which intersect with the hip and/or valley members are in turn attached to these members at common intersecting points so that corresponding rafters of the adjacent intersecting planes of the roof form pairs which are mutually perpendicular to each other when viewed in plan. Thus, the hip or valley members function similar to *o o the ridge board, however in contrast, the hip or valley members are required to act as load bearing members for the cladding weight and/or other loads in a similar manner as to the function of the rafters themselves.

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oo0 o.o 15 Finally, if the roof is to be clad with conventional o roofing tiles, tile battens are attached perpendicularly across the rafters at prescribed spaced locations to form a platform on the roof plane on which the tiles may be laid.

*c0e4o 20 This type of roof framing system has proven itself to be advantageous in two ways. Firstly, the system is readily adaptable to different and sometimes complicated house plan o~rr layouts, and secondly, the system allows the designer/ architect scope in making variations to the roof to give it 25 a characteristic visual appearance with the incorporation of dutch gables, truncated gables etc.

The second type of roof framing system is essentially a progression of the first type in that the two dimensional truss mechanism effectively formed by a pair of rafters and interconnecting ceiling joists mounted to the ridge board, is actually replaced by discrete preformed two dimensional truss members usually made from steel members. Basically, there are considered to be four types of trusses suitable

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5 for this type of'roof framing system, namely the King-post truss, the Fink truss, the Warren truss and the Howe truss.

In constructing a roof framing system using preformed steel trusses, ridge boards and/or hip or valley members are not required, thereby improving the cost effectiveness of this type of system. The discrete preformed two dimensional truss members are attached across opposing walls of a house to be disposed in vertical planes with the apices of the various trusses being disposed rectilineally corresponding to the ridge of the roof. If necessary, the steel trusses are stiffened transversely by installing cross-bracing extending between the apex of one truss member to the toe of another member transversely spaced therefrom, whereby the bracing is attached to appropriate mounting points 15 provided by the chords of any intermediately disposed truss members.

In order to support the cladding elements, the upper chords of the truss members have attached thereto battens or the like extending perpendicularly across the chords to define platforms on the planes of the roof on which the cladding elements may be laid.

r 4* 9 a C 9 9* 4 9 .9 A drawback of this type of roof framing system, however, is that it is not as versatile as the timber framing system in providing scope for designers/architects in designing cc 25 elaborate roof designs. Moreover, the steel truss system does not readily lend itself for house plan layouts involving anything more than a simple rectangle or L shape due to the difficulty in forming hips or valleys in the absence of a frame skeleton. Furthermore, this system is not as adaptable to variations in visual appearance such as the incorporation of dutch gables or the like, than is the case in the timber framing system.

It is important to note that both roofing systems described

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6 above consider the support of roof cladding and associated loads (wind and live loads) in a two dimensional context.

Furthermore, in the timber frame roofing system, the ridge board and/or hip or valley members are of uniform size and the frame defined by them is incapable of independent erection without the support provided by the rafters. In short, the frame formed by the ridge board and/or hip or valley members is really only providing a means by which the rafters may be connected and interconnected to form the load bearing structure of the roof. Although the steel truss roofing system further refines the situation by 0o removing the ridge board and/or hip or valley members o altogether, the truss members which form the support o mechanism for the roof are required to be of a fixed size a 0 o 15 and equal spacing and thus are not directly related to the a' ,particular loading experienced by them, which is also the a, 0 case in the timber frame roofing system.

Sa #9 Thus in both systems, no regard is had to the actual loading requirements of the roof and accordingly spacial 20 and size considerations predominate, usually resulting in gross inefficiencies due to overdesign throughout the entire roof system.

Accordingly, it is an object of the present invention to provide a roof framing system which is designed having 25 regard to loading upon the entire roof structure and which system is capable of being highly modularised to enable a relatively inexpensive and highly efficient design of roof to be achieved which proffers most of the advantages provided by both of the aforementioned types of roof framing system.

In accordance with a first aspect of the present invention, there is provided a pitched roof framing system for r -7mounting atop a roof supporting means for houses comprising:a space frame to form the load bearing skeleton of the roof having a plurality of outwardly extending limbs; and a plurality of cladding support members attached at one end thereof to said space frame for supporting the cladding elements of the roof and at the other end to either said roof supporting means or said space frame 10 as required; 0 4 6 wherein the outer ends of said outwardly extending t limbs are mountable to said roof supporting means, said roof supporting means comprising point load Sbearing members adapted to fix the outer ends of said plurality of outwardly extending limbs of said space frame.

Preferably, said space frame comprises primary beam members wherein said primary beam members are interconnected by connection means to form said load bearing skeleton and said cladding support members comprise secondary beam members, where both beam members are in the form of trusses.

Whilst the connection means may be of any suitable form, it is preferable that the connection means comprises a joint connector unit having a plurality of integrally connected male or female fasteners formed in a particular angular spacial relationship, whereby said fasteners co-operate with complementary fasteners respectively provided at at least one end of a said primary beam member to which said connection means is to be attached to form a joint whereby the male fastener is fixedly connected to the complementary 8 female fastener, or vice versa, in said joint arrangement by a fixing means, aniL the particular angular spacial relationship between the fasteners of a said joint connector unit is that required to form the primary beam members into the required shape for the load bearing skeleton of the roof.

Preferably, said primary beam members are in the form of King-post trusses.

Preferably, said secondary beam members are in the form of ,0 10 space trusses comprising a pair of parallel spaced upper *9 oa chord members and a parallel equi-spaced lower chord oa o member, whereby said upper chord members are attached to -the lower chord member respectively by V-shaped diagonal web members. Alternatively, the cladding support members 15 may comprise King-post trusses.

Preferably, said roof supporting means comprises intermediate point load bearing members adapted to fix an intermediate point or points of said limbs.

In accordance with another aspect of the present invention, *,tI 20 there is provided a method for constructing a pitched roof I ,t for a house on a roof supporting means comprising:t t t determining the desired shape of a space frame to support cladding means having a plurality of outwardly extending limbs for mounting on a roof supporting means; determining the structural requirements for the individual limbs and the space frame as a whole having regard to the load conditions to be applied to said frame; forming said limbs and obtaining appropriate connections therefor; mounting the outer ends of said plurality of outwardly extending limbs onto said roof supporting means; and attaching a plurality of cladding support members at one end thereof to said space frame and attaching the other ends of said cladding support members to either said roof supporting means or an outwardly extending limb of said space frame, as required in accordance S 10 with said determination.

4 t The invention will b1 better understood in the light of the i.i following description of several embodiments thereof. The description of the embodiments is made with reference to ,r t the accompanying drawings, wherein:- Figure 1 is a perspective view of a conventional timber roof framing system; Figure 2 is a perspective view of a conventional steel :truss roof framing system; Figure 3 is a perspective view showing an arrangement of the space frame mounted atop a roof supporting I means to provide an L-shape type pitched roof in accordance with the first embodiment; Figure 4 is a similar drawing to Figure 1 but showing L C some of the space trusses in position; Figure 5 is a similar schematic view to Figures 3 and 4 from the other side of house showing further space trusses in position and also showing the provision of a dutch gable at one end of the house; Figure 6 is a perspective view of a King-post truss which forms the primary beam members of the skeleton; Figure 7 is a plan view of the Y-type joint connector unit interlocked with the ends of three different 10 composite beams in the locked position; Figure 8 is a side elevation of the Y-type joint connector unit, showing how a composite beam is brought from an angular offset position into a locked position, and also showing the provision of a vertical support rod; Figure 9 is an end elevation taken along view AA of Figure 7; Figure 10 is a plan view of the right angle joint connector unit interlocked with the ends of four different composite bees in the locked position; Figure 11 is an end elevation taken along view BB of o 'Figure Figure 7' is a plan view of the Y-type joint connector '0 15 unit interlocked with the ends of three different to@ composite beams in the locked position, in accordante with an alternative embodiment; Figure 8' is a side elevation of Figure 7' taken along view BB'; Figure 9' is an end elevation of Figure 7' taken alo'"; view AA'; f"i Figure 10' is a plan view of the right angle connector unit interlocked with the ends of four different composite beams in the locked position, in accordance t 25 with the alternative embodiment; I t Figure 11' is an end elevation taken along view CC' of tt ^Figure e SFigure 12 is an oblique view of a space truss which forms the secondary beam members; Figure 13a is a plan view of the space truss shown at Figure 12; Figure 13b is a side elevation of the space truss shown at Figure 12; Figure 13c is an end elevation of the space truss shown at Figure 12; Figure 14 is a plan view showing two pairs of space ii.

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It 15 It I 1 It CI I c trusses attached to a composite beam by respective pin arrangements; Figure 15 is a sectional end elevation taken along view DD of Figure 14; Figure 16 is an oblique view of the roof supporting means connector connecting the outwardly extending limbs of the space frame to the roof supporting means located at the corners of the house defined by the intersection of two perimeter walls of the house; Figure 17 is a plan view of Figure Figure 18 is an oblique view of the roof supporting means connector for connecting outwardly extending limbs of the space frame to roof supporting means located intermediate the ends of a wall of the house; Figure 19 is a sectional schematic view of one form of eaves unit; Figure 20 is an end view showing the interconnection between the top chord of a space truss and the eaves soffit of Figure 19; Figure 21 is a side elevation of another form of eaves unit; Figure 22 is an end elevation of the eave soffit shoring the connection of the top chord of the space truss to the eave soffit; Figure 23 is a side perspective view of the connector arrangement for a dutch gable; Figure 24 is a detailed fragmentary perspective view of the gable joint connector unit and arrangement for a gable extension; Figure 25 is a detailed perspective view of the connection between a barge board mounting plate and corresponding limb member; Figure 26 is a detailed perspective view of the gable top connection; Figure 27 is a perspective view of a timber King-post truss which is used as the primary and secondary beam I(i I: i 4rC-' C C:I

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i i 12 0O S 1' 0 *9 *0 Sd 0 01 15 0 o members in the roof framing system described in the second embodiment; Figure 28 is a plan view of the Y-type joint connector unit used to connect King-post members comprising the skeleton in accordance with the second embodiment; Figure 29 is a side elevation of Figure 26; Figure 30 is a plan view of the right angle type joint connecter used in the second embodiment; Figure 31 is a side elevation of Figure Figure 32 is a side elevation of a universal joint connector used in the second embodiment; and Figure 33 is an end view of the universal joint connector shown at Figure Referring to Figure 1, a typical flush gable roofing system is depicted. The construction of this roof first entails creating the ceiling platform by mounting a top plate or wall plate 1 to the top of the perimeter wall of the house and iiternal partitioning walls. Next, ceiling joists 2 are disposed in spaced parallel coextending relationship to 00 1 0 *Eiw 0040 a 0904O 9 0 s o~ 20 each other so that the ends of each ceiling joist are nailed or otherwise fastened to wall plates of opposing walls. Consequently, the ceiling joists perform the functions of preventing the opposing walls from splaying apart, providing mounting points for the ceiling, and via ceiling joist runners 4, struts 7, and purlins 6, providing mounting points to prevent the rafters 3 from excessive sagging. Thus, the platform formed by the ceiling joists and wall plates combines with the walls of the house to define supporting means for the roof.

After the ceiling joists are located, ceiling joist runners 4 are mounted perpendicularly and end on to the ceiling joists by hangers 5. The ceiling joist runners are particularly disposed to provide mounting points intermediate the joists for props or struts 7 which are -13intended to support underpurlins 6 to be described in more detail later and, if necessary, for propping the ridge board 9 temporarily in position.

After the ceiling joist runners 4 are located in their requisite locations, the ridge board 9 is temporarily suspended by vertical props (not shown) mounted at the upper ends to the underside of one end of the ridge board 9 and at the other end to a wall plate 1, ceiling joist 2 or ceiling joist runner 4.

10 Once the ridge board 9 is suspended in this manner, the r rafters and, if appropriate, hip and valley beams or rafters are connected at one end to the ridge board and at the other end to a ceiling joist 2 or wall plate 1. The *.4 arrangement of the rafters 3 is particularly important to provide the main cladding supporting means of the roof.

Moreover, the rafters 3 are arranged in pairs which are connected at their upper ends to either side of the ridge board 9 at a prescribed longitudinal position along the ridge board which position is in coplanar vertical alignment with a corresponding ceiling joist 2 to which the lower ends of each of the pair of rafters 3 is connected at the respective ends of the ceiling joist. In this manner, the pair of rafters and ceiling joist combine to form an E effective triangular vertical truss mechanism which is 25 perpendicular to the ridge board 9. This truss mechanism can be strengthened by the attachment of a collar tie 8 disposed in parallel spaced relationship to the ceiling joist of the truss mechanism and situated approximately half way up the truss to be fixed at opposing ends to intermediate portions of opposing rafters of the truss mechanism. In the usual domestic house situation, collar ties 8 are provided generally every third or fourth rafter pair.

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14 In cases where the rafters 3 are relatively long, underpurlins 6 are attached to the underside of the rafters to extend perpendicularly across each rafter provided in the one roof plane. Thus, the purlins 6 are disposed in parallel spaced relationship to the ridge board 9 at intermediate positions along the rafters. As previously described, the underpurlins 6 are supported by struts 7 which are connected at their upper ends to the purlins and at their lower ends to the ceiling joist runners 4 or ceiling joists 2 themselves.

s o. .In the case where tiles 11 are used to clad the building, tiling battens 10 are attached by nailing or other fixing means to extend perpendicularly across the rafters 3, the full longitudinal extent of the roof plane. The tiling 15 battens 10 are spaced a prescribed distance apart to enable tiles 11 to be laid thereon in overlapping relationship to each other as shown in Figure 1.

Now referring to Figure 2 of the drawings, a typical roof framing system of the steel truss type is shown which essentially comprises a series of vertically disposed Fink t trusses 21 to 25 which are positioned in parallel spaced relationship to each other upon roof supporting means comprising the walls of a house which is rectangular in C E plan.

cc cc Each truss comprises a pair of upper chord members AB and AC which are downwardly angled to define an apex A, and a lower chord BC which spans the truss horizontally and performs a similar function as the ceiling joist in the timber roof framing system. The Fink truss arrangement is characterised by the provision of four web members DE, AE, AF and GF. The web members are particularly disposed to form the Fink truss by: firstly, the member DE at one end being fastened to the point D intermediate the upper chord

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AB such that the length AD is approximately equal to the length BD, and fastened at the other end to the point E intermediate the lower chord BC such that the distance BE is approximately one-third of the overall length of the cord BC; secondly, one end of the member AE being fastened by welding or the like to the apex A of the truss and at the other end to the point E, thereby forming a V-shaped web when combined with the member DE; thirdly, fastening one end of the member AF to the apex A and the other end to the point F which is intermediate the lower chord BC such that the distance FC is approximately one-third of the total length of the chord BC; and fourthly, fastening one end of the member GF to the point G which is intermediate the upper cord AC such that the distance AG is equal to the distance CG and at the other end to the point F, thereby combining with the member AF to form a V-shaped web which is the reverse of the web formed by the members DE and AE.

This type of truss is formed as a discrete truss, whereby the upper chords AB and AC of each truss form a similar I 20 function to the rafters 3 in the timber roof framing system, the lower chord BC performs the function of the "LCtS ceiling joist 2 and/or collar tie 8, and the webs DE, AE, AF and GF perform a similar function to the props 7 and underpurlins 6, whereby all of these functions are achieved t cc 25 within a two dimensiono, plane.

In constructing a roof using the steel truss roof framing system, the Fink trusses 21 to 25 are preformed to the requisite size and are positioned upon top plates or wall plates disposed upon the perimeter of opposing walls of the house.

In order to provide lateral stability to the truss members, wire ties or bracing strips are attached between the apex A of each truss and the toes B and C of another truss which 4" 16is the second or third truss spaced from the first truss.

For example, as shown at Figure 2 of the drawings, the truss 23 has a wire tie attached at one end to its apex A3 and at its other end to the toe B1 of the truss 21, and another wire tie attached to the apex A3 and to the toe C1 of the truss 21. Similar lateral support can be provided by attaching oppositely disposed ties extending in the other direction from the apex A3 to respectively attach to toes B5 and C5 of the truss 10 For additional strength, these ties may be fastened .:..*intermediate their lengths to intersecting points of the upper chords of intermediate trusses. For example, the wire tie A3B1 would be welded or otherwise fastened to the os. underside of the upper cord A2B2 of the truss 22 at the *.0 15 point where the wire tie intersects therewith. After each of the trusses have been positioned and are appropriately braced, battens or the like can be positioned across the upper chords AB or AC of the respective roof planes to *:.Ott support the laying of tiles or other cladding thereon.

a- I As can be seen from this type of construction, a more economical and efficient type of roof framing system is provided than in the timber roof frami ase, however, because of the preforming of the trusses Qf similar size, C it is difficult to apply this type of construction to houses other than of rectangular type plans. Furthermore, it is similarly difficult to incorporate modifications to the roof such as dutch gables, truncated gables or changes in ridge elevation without interfering with the structural aspects of the roof.

The first principal embodiment of the invention is directed towards a pitched roof framing system of a house plan as shown at Figures 3, 4 and 5 of the drawings which is of an L-shape and where the roof is designed to include changes 1 17 17 in elevation of the ridge, hips and valleys, and a dutch gable.

As shown in the drawings, the house is provided with a perimeter wall 33 which is generally of L-shape and which has roof supporting means including columns 35 incorporated into these walls at each of the corners formed by the intersection of adjacent walls, and at an intermediate point represented by the column 35a, which column 35a is generally opposite to the column 35b provided at an 10 internal corner defined by intersecting orthogonal walls ,t 33b and 33c.

Sr r t t tI The columns 35 are of predetermined design to oppose lateral forces and particularly outwardly directed lateral r forces applied to the top of the column. For example, the columns may be cast from concrete reinforced with vertically extending steel rods to form part of the footings of the building. Accordingly, such columns could be formed at the time of laying the footings and the pad for the building.

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Dependent upon the location of the columns 35, the tops of each column are provided with a roof supporting means connector 37 being of a type shown at Figures 15 and 16 or cttt t Figure 17 of the drawings. Moreover, in the case of the column 35 disposed at the outer corners of the building, a connector 37a of the type shown at Figures 15 and 16 is used. At these locations, the bracket portion 38 of the conhector 37a is actually fastened to the inside corner of the inner perimeter wall so that the bolt portion 39 is upstanding to define a mounting point for the roof framing system. In the case of the column 35b located at an I internal corner, the roof supporting means connector is of substantially the same design as that shown at Figures and 16 except that the bracket portion is used in the I; a i 18 reverse manner to be fastened to the inside corner of the inner perimeter walls at this particular location, opposite to that in the previous case. Nonetheless, the connecter can be adequately fastened to provide an upstanding fastening bolt portion which defines a mounting point for the roof framing system.

Finally, a connector 37b of the type shown at Figure 17 of the drawings is used for intermediately located roof supporting means 35a. At these locations, the bracket portion 41 thereof can be simply flush mounted to the top of the internal perimeter wall to provide a mounting point for the roof framing system.

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'i, cCt 2I 4;z 10 The roof framing system essentially comprises a space frame 43 constructed from a series of primary beam members 45 and cladding supporting members constructed from secondary beam members 47.

The primary beam members 45 may be unsupported or, as in the case of the present embodiment, supported by either single or double king-post truss arrangements, dependent upon the applied load to span ratio of the beam. The principal member of the king-post truss unit, as shown in Figure 6 of the drawings, is a composite beam 51 comprising double unequal angle members 51a and 51b of particular dimensions such that the depth of the beam is greater than the composite breadth of the beam. The unequal steel angle members 51a and 51b are of particular dimension and are fixed back to back in such a position so that the smaller dimensioned flanges of the angle members constitute breadth flanges for the beam and the larger dimensioned flanges of the angle members constitute depth flanges for the beam, providing an overall T-shaped beam in cross section. The opposing backs of the angles 51a and 51b are fixedly spaced apart by a plurality of fixing blocks 52 disposed at the i 19 ends of the beam and intermediate the beam. A steel rod 53 connecting the ends of the beam via a king-post 55 forms the tension component of the truss. The king-post 55 is formed of steel tube of particular dimension fixed at right angles to the longitudinal extent of the beam 51 against an intermediate fixing block 52a and the corresponding intermediate point of the steel rod 53 at either the midspan, third span or some intermediate span length in the case of the beam 51 being intermediately supported by an internal truss support 54, such as an internal wall 56 as shown in Figures 3 and 4. In the instance where the beam is to be internally supported atop an internal wall, the king-post 55 will have affixed to the lower contacting end, a connector plate assembly for attaching to the wall plate 15 of the internal wall. The opposite ends of the steel rod 53 have corresponding end fixing b.,>cks 52b provided at the opposite ends of the beam 51 in the manner shown at Figure 6. Similarly, the king-post 55 is welded at its opposite ends to fixedly interconnect the steel rod 53 and the beam rt t t t Ir II t: t 4 u~rk I 44 ii 4

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t r The king-post truss configuration is basically one of the simplest truss mechanisms by which a beam is able to withstand larger than normal uniformly distributed vertical loading and hence is ideal to use in the construction of S 25 the space frame of the present invention. Furthermore, the cc v beam of the truss is able to be tensioned or even pretensioned in order that the deflection the beam would normally experience, if unsupported, will not occur.

Tension is applied by the steel rod 53 acting upon the king-post 55 to force it up into the beam 51, whereby the king-post, naturally, is in compression.

In order to form the space frame 43, the primary beam members are connected and interconnected by joint connector units 49 in a prescribed manner to form the load bearing I7

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20 skeleton of the roof. Accordingly, the primary beam members 45 which form the load bearing skeleton are divided into two functional types, those 45a and 45b defining the ridge or backbone of the space frame and those 45c, 45d and 45e which form outwardly extending limbs of the space frame. The ridge members 45a and 45b are connected at their respective ends via joint connecter units 49 either to a plurality of adjoining ends of limb members 45e, or 45e, or to a plurality of adjoining ends of ridge and limb members respectively, as shown in Figures 3, 4 and of the drawings. The ridge members are further divided "into two further types: horizontal ridge members 45a and *'P9 0 oblique ridge members 45b; and the limb members are further be P'oo divided into three further types: hip limb members 15 valley limb members 45d and balancing limb members 4.4 These further types of primary beam members are determinedly the shape of the roof which is desired, but structurally are identical.

The design of the space frame can be modularised particularly in view of the pitch of most roofs being standardised at 180 or 200. Accordingly, the shape of a roof can effectively be predetermined by positioning limb S members 45c and 45d at each of the corners of the building and connecting these to ridge members 45a and 45b at 25 appropriate locations adhering to the pitch standard and Spredetermined angular spacial relationships between interconnecting ends of adjoining primary beam members by standardised joint connector units 49. In this manner, the length of the primary beam members can be easily predetermined within these parameter. to simplify construction of the space frame on site with preformed components.

Using this methodology of construction, the joint connector units 49 are divided into essentially two different types, IiI -21one being the Y-type 49a depicted at Figures 7 to 9 of the drawings and the other being the right angle type 49b depicted at Figures 10 and 11 of the drawings.

Essentially, the Y-type joint connector plate unit 49a is used at the junction between two hips and a ridge as shown at the junctions 50 of the roof in the present embodiment, or at the junction of two ridges and a hip, whereby one ridge is downwardly angled relative to the other as shown at the junction 52.

.9 9 1 e 0 The right angle type joint connector plate unit 49b is used 9r 9 at a junction involving a valley and two ridges, whereby one ridge is required to be upwardly angled relative to the S, a other ridge. At this junction, as shown at 54 of the o drawings, the joint needs to be balanced at the opposite side of the valley and hence provision is required to be made for a balancing limb member 45e for which the roof supporting means 35a is provided.

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In the present principal embodiment, the joint connector C

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units 49 essentially comprise steel rectangular plate members 57 of uniform size having the principal dimension for positioning in the vertical plane. The respective plates 57 are radially disposed and are connected together c centrally by weld to form integral units of various cr predetermined angular configurations. The plate members 57 have a thickness sufficient to fit within the spacing provided between the opposing backs of the depth flanges of a composite beam to facilitate mutual attachment of a plate member of a joint connector unit and the end of the beam.

The mutual attachment is achieved by the plate member 57 being provided with a pair of diagonally opposed recesses 58 provided along the intended upper and lower edges of the plate member to form a male fastener and the end of the composite beam 51 being provided with a pair of diagonally 22 opposed fixing blocks 52 between the depth flanges to form a female fastener. The recesses 58 and fixing blocks 52 are correspondingly arranged and are of complementary shape to enable interlocking engagement between them in a locked position when the plate and beam are brought into axial alignment and so combine to form a locking means.

As shown in the drawings the outermost recess 58a is disposed along the upper edge at the distal end of the plate and the innermost recess is disposed along the lower 10 edge at the proximal end of the plate. The fixing blocks 52a and 52b at the end of the beam are disposed conversely to this so that the innermost fixing block 52a is disposed along the upper edge at a proximal position of the end of ,0 the beam and the outermost fixing block 52b is disposed 9,99 15 along the lower edge near the distal end of the end of the .i beam.

By this arrangement, as best shown in Figure 8 of the drawings, the male and female fasteners from an angularly offset position are simply rotated towards an axially aligned position at which the corresponding recesses and fixing blocks interlock. At this locking position, the interlocked festeners oppose relative axial movement between them and relative rotational movement in the direction of the principal bending moment. The fasteners 25 are unlockingly disengaged by simply rotating them from the locking position in the direction opposite to the principal being movement.

In an alternative embodiment, instead of using corresponding recesses and fixing blocks as locking means, the male and female fasteners are interlocked by passing a series of bolts of particular size through aligned apertures in the plate 57 and the depth flanges at the end of the composite beam, such that the end of the plate 57 is Li 4' 23 fastened centrally between the opposing backs of the angles 51a and 51b. The bolts are then fastened by suitably sized nuts so that forces applied or transmitted to the joint are resisted by the sheer capacity of the bolt and not the joint plate itself. This form of locking means embodiment is'shown in Figures 7' to 11'.

As the two most common roof pitches currently in use are 18 0 and 200, which in terms of hip/ridge or valley/ridge the mean angular difference equates to less than a degree, I 10 it is possible by trimming beam ends and locking means e o placement of either embodiment to satisfy both roof pitches with the one type of connector unit, dependent upon the particular type of joint required.

.4 In the case.of the Y-type joint connector plate unit 49a, the connector section 57a is intended to connect the end of a horizontal ridge member 45a, and the connecting sections 57b and 57c respectively are intended to connect to the end 4I.,L of hip limb members 45c, in the case where the ridge adjoins to hips as shown at 50. In the case where a ridge adjoins another ridge and a hip as shown at 52, the connecting section 57 again is intended to connect to the I end of a horizontal ridge member 45a, however, in the present embodiment, the connecting section 57b is intended to connect to the end of an oblique ridge member 45b, and the other downwardly angled connecting section 57c is intended to connect to the end of a hip limb member In the case of the right angled type joint connector plate unit, a four way junction must be provided as shown at Figures 10 and 11 or 10' and 11' of the drawings. In this particular arrangement, the horizontal connecting section 57d connects to the end of a horizontal ridge primary beam member 45a, the upwardly angled connecting section 57e which is orthogonally directed in plan to a downwardly 24 angled connecting section 57f, connects to the end of an oblique ridge member 45b, the downwardly angled connecting section 57f which is directed at an angle of approximately 450 in plan to the horizontal connecting section 57d, connects to a valley limb member 45d, and lastly the downwardly angled connecting section 57g, which is orthogonal to the horizontal connecting section 57d in plan, is connected to a balancing limb member 45e. In the case of the view of the right angle joint connector unit 49b shown at Figure 11 of the drawings, the angling of the 0 connecting sections 57e, 57f and 57g, relative to the 0 0 horizontal, are each at the pitch angle of the roof.

,In either type of joint connector unit, the unit optionally can be welded at its underside to sit atop a vertical a support rod 56 which is provided with a saddle 56a at its lower end to repose atop an internal wall, thereby providing further vertical support to the completed space frame.

i The secondary beam member 47, in the present principal Sembodiment, is in the form of a space truss 61 as shown at Figures 12 to 15. The space truss 61 is composed of two generally parallel top chords 63 supported by two V-shape diagonal web members 65a and 65b respectively attached to a common bottom chord 67 and a plurality of parallel spaced S transverse web members 65c extending between the top chords.

The top chords 63 are spaced apart a set distance 600 mm) and each are formed from rolled equal angle sections so that one of the flanges 63a of each section depends at each side of the truss in parallel spaced relationship to the other and the other flanges 63b are disposed in coplanar relationship with each other and project inwardly of the 7 truss member oppositely of each other to define the top of the truss.

U The web members 65 are formed of steel rod of varying size, according to span. The diagonal web members 65a and are comprised of discrete diagonally placed web elements which extend sequentially between the top and bottom chords so that consecutive pairs of elements form a V-shape spanning the top and bottom chords as viewed from a side elevation as shown at Figure 9. Furthermore, the bottom chord 67 is equidistantly disposed relative to the top chords 63 so that the respective web members 65a and ,4i form a V-shape when the truss is viewed in end elevation as I, LI, shown at Figure 10 of the drawings, and the angular 'positioning of the web elements with respect to the chords I- 15 is fixed by welding or the like. The top chords 63 are spaced apart by the transverse web members 65c which are also welded to the respective chords at their opposite ends. The transverse web members 65c are positioned in or, general alignment above each node formed by the junction of 20 web elements 65 and the bottom chord 67.

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The various components of the truss combine to form a self sustaining load supporting unit truss unit having a high capacity for vertical loading. Accordingly, a series of trusses formed in this manner are adapted to support steel i 25 or timber roof purlins or tile battens fastened across the trusses perpendicular thereto to enable the roof cladding to be laid thereon.

The space trusses are fastened to the primary beam members in a series of aligned truss pairs which are disposed and fixed at successive longitudinal locations along the primary beam members 45 so that the axial loading of one truss of a pair is opposed by the other truss of the pair.

The fixing of the inner ends of the space trusses to the

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26 primary beam members is facilitated by the use of a special common fastener, which will be described in more detail later. The other end of each truss either rests upon an adjacent internal perimeter wall and connects to an eave unit 69, which in turn is fastened to the perimeter wall, or to an adjacent limb member as would be the case with trusses near a valley limb member 45d as shown at Figure of the drawings. Alternatively, when an eave line is not desired or required, the other end of the appropriate trusses 61 can be fastened directly to a wall plate provided on the top of the corresponding portion of the perimeter wall 33, as shown at Figure 4.

t I€ p With the top chords 63 of the truss members 61 being formed of rolled equal angle sections, fastening of either end of the truss is a simple matter, whereby the top flanges 63b of the trusses each have a connector plate 70 welded to the t l top thereof, so that the connector plates protrude out longitudinally of the end of the truss as shown in Figures 14 and For fastening the ends of the truss members 61 to a k composite beam 51, the ends of the connector plates are angled downwardly commensurate with the pitch of the roof so that they can sit in coplanar relation upon the tops of the corresponding breadth flanges of the angle members 51a and 51b forming the composite beam and be fastened to the beam by the use of the common fastener.

The common fastener is in the form of a pin arrangement 68 comprising a central shank 72a, a head 72b disposed orthogonally to the shank at one end thereof, a pair of pendent virgate fasteners 72c disposed in substantially parallel relation to the shank one at each opposing end of the head, and a biasing locking means 72d disposed at the other end of the shank.

D~--jr 27 The central shank 72a of the pin is sized to be accommodated between the adjacent depth flanges of the composite beam 51.

The virgate fasteners 72c are sized to be accommodated within corresponding opposing pairs of apertures 74a and 74b respectively provided in the protruding ends of a pair of opposingly aligned connector plates 70 of an aligned truss pair, and also in the opposing breadth flanges of the composite beam. Consequently, the corresponding apertures 74b in the breadth flanges of the composite beam are 9* 4 9 4.

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arranged in sets of two opposing pairs for each truss pair, the distance between the two pairs of apertures corresponding to the distance between the apertures 74a of the pair of connector plates 70 which are provided at the 15 end of each space truss. Furthermore, the distance between the corresponding apertures 74b of an opposing pair of apertures 74b provided on the composite beam corresponds to the distance between the virgate fasteners 72c of a pin arrangement, whereby the spacing of these apertures 74b from the space between the angle members is equidistant so that a pin arrangement can be simply pressed into position with the central shank 72a reposing in the space between the angle members and the virgate fasteners 74c reposing in the common pair of opposing corresponding apertures formed by the coaxial alignment of the opposing pair of apertures 74b of the composite beam with the apertures of the opposingly aligned connector plates 70 of a truss pair, the ends of which repose upon the respective breadth flanges of the composite beam.

Although the weight of the total roof system is such that the space trusses are unlikely to move upward, the biasing locking means 72d in the form of a steel deflection plate is provided on the tip of the central shank 72a to counter 28 any such movement in any event, once the pin arrangement is pressed into position. Moreover, the deflection plate is barb shaped having a transverse expansion greater than the spacing between the angle members and capable of biased deflection inwardly to facilitate pressing the central shank 72a downwardly in the one direction between the angle members. Additionally, the central shank is sufficiently long so that the deflection plate can clear the bottom edges of the depth flanges of the beam when the head 72b of the pin arrangement engages the respective ends of the pair of adjoining connector plates 70, at which position the deflection plate can return to its expanded position locking the pin arrangement from direct withdrawal in the opposite direction. Withdrawal can nonetheless be S. 15 perfected manually, if required, by simply biasing the deflection plate inwardly and manoeuvring the pin arrangement axially in the opposite direction until the deflection plate enters the spacing between the angle members, at which point the pin arrangement can be easily extracted.

tee. r t In another alternative embodiment, the connector plates of the truss members are formed by having a portion cut out a marginal distance from the end of the depending side S flanges 63a so that the remaining upper web 63b at the end of the truss forms a protruding flange plate which f constitutes a connector plate and which may be fastened by Sc bolting or welding, or by the pin arrangement 72, to the top of a beam 51 at an intermediate location along the top of a primary beam member In the case of the other end of the space truss being fastened to a limb member, the end of the truss may be simply cut so as to form similar flange plates for connection at appropriate locations along the top of the beam 51 of the limb member.

29 In the case of being connected to an eave unit .69, the top chord of the space truss 61 may simply rest upon the i| perimeter wall 33 and be attached to a similarly formed rolled equal angle section eave soffit 71 in one of two ways which in turn is fixedly attached to the perimeter wall.

The first of these ways is shown at Figures 18 and 19 of the drawings, whereby one end of the angular eave soffit 71 is pivotally mounted to the lower end of the top chord 63 by a bolt or pin fastener 73, externally of the perimeter I wall 33 so that the soffit extends inwardly towards the i perimeter wall to be fastened thereto via a gusset plate i whereby the eave soffit 71 is substantially horizontally 1 disposed. In this case, the top chord 63 of the space I 15 truss 61 rests upon the top of the inner perimeter wall 33a I i and the eave soffit 71 is directed inwardly over the top of E c the outer perimeter wall 33b so that the gusset plate which is welded to the inner longitudinal end of the soffit 71 is fastened vertically to the inner perimeter wall 33a by horizontally disposed anchoring bolts. By Sadopting this particular arrangement, the eave soffit 71 i "can be pivotally mounted to the end of the top chord 63 I prior to fixing the position of the space truss 61 thereof so that the angular eave softit may swing down upon placement of the truss to be positioned at the appropriate i location as shown at Figure 18 of the drawings.

The other way of fastening the top chord 63 of the space truss 61 to the eave soffit 71 involves modification of the eave soffit to include a fascia plate 77 at the outermost extent of the soffit, enabling the location of a gutter or the li'.e thereon. As shown at Figures 20 and 21 of the drawings, the eave soffit 71 has a metal fascia plate 77 welded thereto at the outermost extreme thereof whereby the -j 30 metal fascia plate is intended to extend upwardly generally perpendicular to the longitudinal extent of the soffit.

The upper extreme of the fascia plate 77 is in turn pivotally mounted to the outer end of the top chord 63 of the space truss by a pin 79. The fascia plate 77 is rightangled so that one web 77a is juxtaposed in coplanar relationship with the upstanding web 71a of the soffit and the other web 77b is disposed transversely of the soffit 71 to provide a mounting surface. In this arrangement, the eave soffit 71 need not be provided with a gusset plate but instead, may simply be fastened to the top of the external brickwork 33b by means of a vertically disposed fastener in the form of an anchor bolt or the like extending through an aperture provided in the lower web 71b of the eave soffit.

15 In order to form a dutch gable as shown at Figure 5 of the drawings, a variation on the Y-type joint connector plate l unit is utilised to provide a gable joint connector plate unit, which is used in conjunction with a gable ridge beam.

The gable joint connected plate unit 49c is shown at Ott 20 Figures 23 and 24 of the drawings and comprises a Y-type arrangement of steel rectangular plates connecting sections cre 57h, 57i and 57j which correspond substantially identically with coniecting sections 57a, 57b and 57c of the Y-type Sjoint connector plate unit 49a, with the addition of a j 25 fourth connecting section 57k. The fourth connection section 57k is formed of a single rolled steel equal angle which is rectilinearly and oppositely aligned to the horizontal connecting section 57h so hat the junction of the angle forms a peak ridge to enable connection thereto of a similarly configured gable ridge beam 81.

Accordingly, the gable ridge beam 81 is similarly formed of a single rolled steel equal angle of particular dimensions which is bolted to the connecting section 57k in a lap joint arrangement.

IP- i i- C 31 In order to form the apex of the gable, the gable ridge beam 81 projects outwardly from the gable joint connector plate unit 49c to support a pair of rolled equal angle section members 83 which form the barge board mounting plates of the gable. Accordingly, the angle section members 83 are arranged so that one of the legs 83a thereof is disposed at the top of the member to be coplanar with the planar side of the gable and the other leg 83b is disposed in a substantially vertical plane at the front of the gable to provide a plate on which the barge boards may be mounted. The connection of the angle section members 83 o to the gable ridge beam 81 is shown at Figure 24 of the drawings, whereby a specially shaped gusset bracket 84 is bolted in a lap joint arrangement at a flared end 84a to a S 15 corresponding angle section member 83 and is welded at the .14 other tapered end 84b to the corresponding side leg of the go0 a0, gable ridge beam 81.

The lower ends of the angle section members 83, as shown in Figure 25, are mounted to the limb members 45b which form ,,20 hips of the main roof structure and valleys for the gable, 4 by an L shape bracket 85. The bracket 85 is positioned so S that one leg 85a is bolted in a lap joint arrangement to the lower end of the upper leg 83a of the angle section member, and the other leg 85b is bolted between the backs crT(,' of the composite unequal angles 51a and 51b at the required ecC, position along the limb.

C 9 Now describing the method of constructing the roof in accordance with the present embodiment, the principal roof frame shape is firstly determined in accordance with the plan of the exterior wall system of the particular house for which the pitched roof is to be constructed. A series of ridges and sub-ridges are configured to establish particular roof laying pitches, as required, these ridges ii 32 and sub-ridges forming a space frame having outwardly extending limbs.

Primary beam members for forming the space frame are made up of a series of interconnecting truss units of individual shape and size in accordance with: the design load each is deemed to carry, (ii) the proximity of supporting internal walls, and (iii) the type of material used for the frame. Design loads considered are those applied to the roof system as a whole and as a consequence, vary with roof frame configuration. The resultant space frame structure is supported by the roof supporting means provided at various points atop the external walls of the building and o at strategic locations atop some of the internal walls. In accordance with conventional building construction, it is 15 necessary to have the roof supporting means incorporated Sa within the walls of the house at the corners as previously described. In the light of present building methods, however, roof supporting means in the form of columns 35 as previously described are not provided. Consequently it is Oa0f 20 necessary to support the principal roof frame structure internally by strategically located truss members. Thus certain primary beam members 45 are constructed in the form of king post truss units, whereby the king post 55 is .44? extended from the composite hypotenuse member 51 to a point atop a particular internal wall. Consequently, in a beam S member extending from an external wall, the bottom a.

(tension) chord is disposed in a parallel plane to the .4 ceiling platform for that section of the truss unit between the external and internal supports atop the corresponding internal and external walls, and the other (tension) chord is disposed obliquely between the internal support and the upper end of the hypotenuse member 51 which connects to an appropriate joint connector plate unit 49. In the case of a double king-post truss arrangement, one of the king-posts would be extended down to a point support atop the c~ 33 particular internal wall, so that one of the (tension) chords is disposed parallel to the ceiling platform. In the case of a truss unit extending between a pair of joint connector plate units 49, as opposed to an external wall, the intermediate chord would be disposed parallel to the ceiling platform with both king-posts extending down to point supports provided on a pair of corresponding internal walls.

fr. 0 o a 6 h. *B *r OlJ 0 O i 04 0 0 0~ 6 od O 0 a 6o11 *a U 1 0 0 Q*, After establishing the roof supporting means for the house, the space frame 43 is constructed using the primary beam members 45 as previously described and connecting ridge and limb members thereof using joint connector units 49 where appropriate and attaching the outer end of the limb members to the fastening points provided by the roof supporting 15 means.

At this stage, the space frame constitutes a fixed structure which is capable of bearing loads and does not rely upon any other ancillary means for supporting itself.

Consequently, cladding support members 47 in the form of 20 the space trusses 61 are attached in pairs at opposite sides of the ridge members 45a and 45b at their respective inner ends and are attached at their outer ends to the eaves or wall plates of the roof supporting means, or to valley limb members 45d. Where eaves are required, these 25 are formed in the manner previously described virtually simultaneously with the attachment of the outer ends of the space trusses 61 to the perimeter wall 33. Finally, miscellaneous aspects of the roof such as dutch gables or full gables can be provided in the manner described herein.

It should be noted that a special feature of the present embodiment is that the space frame initially supports the erection and placement of the space trusses, however, once 34 the platform base of the roof has been reinforcedby appropriate internal supports as previously described, the system effectively reverses and the space trusses act in a similar way to the rafters in the timber roof framing system to effectively support the space frame and consequently any applied loading. Thus, the loading ability of the roof can be made greater than in the prior art arrangements, whereby the cladding support members effectively compliment the loading ability of the space frame itself to increase the loading ability beyond that provided either by the space frame or the cladding support a members individually.

The second embodiment is substantially similar to the o previous embodiment except that the space frame and o" 15 cladding support members, instead of being constructed from a steel sections and beams, are constructed from timber beams.

In this arrangement, the primary beam members 45 may still be formed of King-post truss arrangements, but wherein the 20 beam is formed of timber rather than a rectangular hollow 0,*0 section, as shown at Figure 27 of the drawings. Thus, the a a King-post truss member 87 of the present embodiment *comprises a timber beam 89 which has its ends connected by a steel rod 91 and is tensioned by the provision of a King- 25 post in the form of steel tube 93 in similar manner to the previous embodiment. The steel rod 91 is bolted at its i iopposite ends to the timber beam 89 by bolt fasteners and the King-post 93 is screwed into or saddle jointed to the midpoint or one-third span point of the beam at one end thereof and welded to the steel rod 91 at the other end.

The cladding support members of the roofing system instead of being in the form of space trusses as in the previous embodiment can also be in the form of timber King-post 1 trusses of the type shown at Figure 27 where the timber King-post trusses are mounted at one end to a ridge member via a universal connector 97, shown at Figures 32 and 33 of the drawings, and at their other end in a conventional manner to the wall plate of the ceiling platform mounted atop the perimeter walls of the house.

The universal joint connecter 97 is formed of angular Tsection metal plate whereby the web portion 97a of the universal joint connecter unit 97 may be vertically disposed and the flange portion 97b forms the top of the S0 connecter. As shown in the drawings, one end of the web portion 97a may be cut out from the flange portion 97b and a the remaining flange portion bent over to form a mounting plate which may be nailed or bolted into the top of the timber beam 89 of a King-post truss member 87 so that the universal connecter unit projects laterally outwardly therefrom to enable fastening of one end of a timber Kingpost truss which forms a cladding supporting means by nailing or bolting the timber beam thereof through the web portion 97a.

The other types of joint connector units required to enable connection of the primary beam members 45 to form the space frame 43 are also formed of similar T-section metal plate c to provide the Y-type of joint connector unit 99 as shown

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c c 25 in Figures 28 and 29 of the drawings and the right angle Sr type of joint connector unit 101 shown in Figures 30 and 31 of the drawings. In these arrangements, however, the flange portion 97b of the plate effectively forms the base of the joint and the web portion 97a is upstanding to be bolted in juxtaposition to one side or the other of a timber beam 89 or alternatively be accommodated within a central groove formed within the end of a timber beam to be fastened thereto by transversely extending bolts.

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36 With this type of construction, the eave unit can still be of the same type of construction described in the previous embodiment. However, with regard to the provision of a gable, the gable ridge beam would be formed from a simple timber beam and the gable joint connector unit 99 would be modified using an additional connecting section of Tsection metal plate to form the connecting section for the gable ridge beam.

It should be noted that in constructing either embodiment of the roof system, a different procedural methodology is involved than is the case with conventional methodologies for roof construction. Moreover, the shape and 9' configuration of the space frame which is provided to er CI t I i support the cladding means, is firstly determined having a regard principally to aesthetics. Once the shape and 4 configuration of the space frame is established, then the structural requirements of the individual limbs of the space frame and for the space frame as a whole are determined having regard to the load conditions to be 20 applied to the frame as a whole. For example, at this stage, the design of specific single or double king post truss units is determined for specific limbs, and internal supports are chosen for supporting appropriate truss units internally.

CII'

Consequently, member sizes and truss configurations are established in accordance with the actual design loads considered to act upon the individual member or section of the space frame, when the space frame system is considered as a whole.

After establishing the structural requirements, the appropriate components forming the roof can be constructed individually and appropriate connecting components obtained, all offsite if desired.

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V 37- Thus, the system is highly modularised to enable rapid construction by a semi-skilled work force at the appropriate time onsite.

It should be noted that the initial support mechanism of the roof frame is the space frame comprising the primary beam members. This is subsequently enhanced by the fixing of the cladding support members comprising the secondary I.beam members to the space frame by appropriate load LI sharing.

I zt 10 It should be appreciated that the scope of the present tj invention is not limited to the particular embodiments I described herein and variations in accordance with conventional engineering practice are envisaged to fall i.d e s c r i b e d h r i a n d v a r i t i n ci c o a n i t h l ,within the spirit of the invention.

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Claims (19)

1. A pitched roof framing system for mounting atop a roof supporting .neans for houses comprising:- a space frame to form the load bearing skeleton of the roof having a plurality of outwardly extending limbs; and a plurality of cladding support members for supporting the cladding elements of the roof attached at one end thereof to said space frame and at the other end to S, either said roof supporting means or said space frame as required; tf wherein the outer ends of said outwardly extending limbs are mountable to said roof supporting means, said roof supporting means comprising point load bearing members adapted to fix the outer ends of said l plurality of outwardly extending limbs of said space St frame.

2. A roof framing system as claimed in claim 1, wherein said space frame comprises primary beam members interconnected by connection means to form said load bearing skeleton, and said cladding support members comprise secondary beam members, where both beam members are in the form of trusses.

3. A roof framing system as claimed in claim 2, wherein said connection means comprises a joint connector unit having a plurality of integrally connected male or female fasteners formed in a predetermined angular spacial relationship, said predetermined angular spacial relationship between said fasteners being that required to 39 form said primary beam members into the required shape for the load bearing skeleton of the roof.

4. A roof framing system as claimed in claim 3, wherein said fasteners are adapted for 'co-operating with complementary fasteners respectively provided at the ends of said primary beam members to which said connection means are to be attached so as to form fixed joint arrangements whereby a said male fastener is lockingly connected to a complementary female fastener, or vice versa, in said joint arrangement by locking means.

A roof framing system as claimed in any one of the preceding claims, wherein a said primary beam member is in the form of a King-post truss.

6. A roof framing system as claimed in claim 5, wherein said King-post truss comprises:- a complete beam formed of a pair of unequal angle sections having a depth flange and a breadth flange, said depth flanges being coextensive and fixed back to pc,: back in spaced apart relation and said breadth flanges extending outwardly in opposite directions and being in coplanar arrangement, the extensive dimension of said depth flanges being greater than that of the breadth flanges; a King-post extending at right angles from said composite beam in the same direction as said breadth section intermediate the ends of said composite section at either a point corresponding approximately to the mid-span or at a point corresponding approximately to one third the span length; -7 40 and tension rod means connecting the ends of said composite beam and the outer end of said King-post.

7. A roof framing system as claimed in any one of the receding claims, wherein said secondary beam members are in the form of space trusses comprising a pair of parallel spaced upper chord members and a parallel equi-spaced lower chord member, whereby said upper chord members are attached to the lower chord member respectively by V-shaped diagonal web members. o.

8. A roof framing system as claimed in any one of the preceding claims, wherein a said joint connector unit comprises a plurality of radially disposed plate members which are centrally connected to form an integral unit, •ri said plate members having a thickness sufficient to fit within the spacing between the corresponding depth flanges of a said composite beam to facilitate mutual attachment of said joint connector unit and the end of a said composite beam so as to form said fixed joint arrangement.

9. A roof framing system as claimed in. claim 8, wherein a *said male fastener comprises a said plate member and a pair of diagonally opposed recesses provided along the intended upper and lower edges of said plate member, and a said female fastener comprises a pair of said spaced apart depth flanges and a pair of diagonally opposed fixing blocks disposed between said depth flanges and towards an end of the composite beam formed by said depth flanges in corresponding relative arrangement to said recesses, said recesses and said spacing blocks being complementary in shape to enable interlocking engagement therebetween, in a locking position whereby said male and female fasteners are interconnected to form said locking means in a manner so as to oppose relative axial and rotational movement between I' iii I o9 C 0 #1 a tr t4 I P CI 4: 4 IC CC rt C 4:i 41 said fasteners in the direction of the principal bending moment, whereby locking engagement is provided by simple rotation of said fasteners to said locking position in the direction of said principal bending moment and unlocking disengagement is provided by simple rotation of said fasteners from said locking position in the direction opposite to said principal bending moment.

A roof framing system as claimed in any one of the preceding claims, wherein a said joint connector unit comprises three said plate members disposed to form a Y- type configuration for interconnecting three of said primary beam members at the junction between two hips and a ridge of said roof or at the junction between two ridges and a hip of said roof, whereby the relative angular positioning of said plate members corresponds to the prescribed pitch of said roof as described in three dimensions.

11. A roof framing system as claimed in any one of the preceding claims, wherein a said joint connector unit comprises four said plate members disposed to form a right angle-type configuration for interconnecting four said primary beam members at the junction between a valley and two ridges of said roof whereby the relative angular positioning of said plate members corresponds to the prescribed pitch of said roof as described in three dimensions and the requisite balancing of said junction opposite to said valley.

12. A roof framing system as claimed in any one of the preceding claims, wherein said secondary beam members are symmetrically aligned around said space frame, whereby each secondary beam member on one side of said space frame is matched by a corresponding secondary beam member on the other side of said space frame. 42

13. A roof framing system as claimed in claim 12, wherein a pair of aligned secondary beams are connected at said one end of each to a said primary beam by a common fastener, said common fastener being in the form of a pin arrangement whereby the shank of the pin is sized to be disposed between the adjacent depth flanges of a composite beam and the opposing ends of the head of the pin are each provided with pendent virgate fasteners disposed substantially parallel to the shank of said pin and adapted to be accommodated within corresponding apertures provided at said one end of said secondary beams for connection to said primary beam and also in corresponding apertures provided in the breadth flanges of said composite beam, whereby the respective corresponding apertures are aligned S~ t to receive said pendent fasteners.

14. A roof framing system as claimed in claim 13, wherein the end of said shank is provided with a biasing locking means permitting entry and axial movement of said shank between said depth flanges of said composite beam in one rdirection to adopt a fastening position and opposing exit and axial movement of said shank in the opposite direction from said fastening position.

I A roof framing system as claimed in any one of the preceding claims, wher.ein said roof supporting means comprises intermediate point load bearing members adapted to fix an intermediate point or points of said limbs, said limbs including a strut extending between a said intermediate point load bearing member and said intermediate point of said limb.

16. A roof framing system as claimed in claim 15, wherein said strut comprises the King-post of a said King-post truss. 43

17. A roof framing system substantially as herein described with reference to the accompanying drawings.

18. A method for constructing a pitched roof for a house on a roof supporting means comprising:- determining the desired shape of a space frame to support cladding means having a plurality of outwardly extending limbs for mounting on a roof supporting means in accordance with conventional structural engineering design practice; determining the structural requirements for the individual limbs and the space frame as a whole having regard to the load conditions to be applied to said frame in accordance with conventional structural engineering design practice; forming said limbs and obtaining appropriate connections therefor; *mounting the outer ends of said plurality of outwardly Sextending limbs onto said roof supporting means; and C C C attaching a plurality of cladding support members at C t one end thereof to said space frame and attaching the other ends of said cladding support members to either said roof supporting means or an outwardly extending limb of said space frame, as required in accordance with said determination.

19. A method for constructing a pitched roof for a house on a roof supporting means substantially as herein 44 described with reference to the accompanying drawings.. DATED this TWENTY-NINTH day of OCTOBER 1991. 4, 4 S S V C4 DR 4 4 DR 4 4 .9 .9 V r44* 4 9* 9 V 9 99 DARYL ARTHUR POOLE Applicant. Wray Associates Perth, Western Australia Patent Attorneys for the Applicant.