EP3963144A1

EP3963144A1 - Framework construction strut

Info

Publication number: EP3963144A1
Application number: EP20729127.9A
Authority: EP
Inventors: Roderick Owen LAVERY
Original assignee: Modular Interiors Ltd
Current assignee: Modular Interiors Ltd
Priority date: 2019-05-02
Filing date: 2020-04-23
Publication date: 2022-03-09
Anticipated expiration: 2040-04-23
Also published as: GB201906173D0; GB2583514A; EP3963144B1; WO2020221983A1; GB2583514B

Abstract

A framework construction strut (11) usable both vertically and horizontally for construction of a framework for a wall (10) comprises a hollow extrusion provided at one of a first pair of parallel and mutually opposite longitudinal sides (13) with a support face (13a) for wall panels (15) and at the other one of those sides with a slot (13b) extending over the full length of the strut and serving for reception of fastening means (21, 22) for use in fastening the strut (11) to a support or to another such strut (11). The extrusion is further provided at each of a second pair of parallel and mutually opposite longitudinal sides (14) perpendicular to the first sides (13) with a respective longitudinal groove (14a) disposed adjacent to the side with the support face (13a) and serving for reception of part of a fixing bracket for fixing the strut to another such strut in a butt joint relationship. In addition, the extrusion has an intermediate bracing wall (16) extending parallel to the first sides (13) and between the slot (13b) and the grooves (14a) to brace the second sides (14) relative to one another and to bound, together with those sides and the side with the support face (13a), a cavity (17) for receiving and concealing another part of the fixing bracket.

Description

FRAMEWORK CONSTRUCTION STRUT

The present invention relates to a framework construction strut, to a framework constructed with use of such struts and to a facing wall constructed with use of the framework.

Struts for use in constructing framework of a kind that can be employed in the construction of internal facing walls for structural walls, for example washroom facing walls intended to be equipped with sanitary ware, are known in a variety of forms. Struts are frequently used to create modular constructions in which the dimensions of a framework can be extended in modular manner to meet a particular site specification and the framework is then clad with wall panels of standard sizes. Such struts are typically made of wood or folded steel, which may satisfy requirements relating to strength, but have limitations with respect to shaping to accept fastenings and to allow secure mounting of heavy sanitary units together with associated pipework and necessary fixtures. Known struts can be relatively labour-intensive to produce, yet heavy and limited in adaptability.

Extruded elongate profile members of light metallic or plastics material, commonly called sections or just extrusions, are widely used for constructional and other purposes, in particular for creating window and door frames and non-structural curtain walls. Extrusions, especially those of plastic, used for such purposes are often integrated in other structures and generally have a limited load-bearing capability. Accordingly, they have not supplanted inherently stronger materials, such as steel, for use in creating self-supporting wall framework intended to carry fittings, for example heavy sanitary ware. Sanitary ware exerts a constant bending load on the framework, especially a load which applies stress to corners and other joints of the framework.

It is therefore the principal object of the invention to provide a framework strut, particularly for construction of a framework for a wall, which is lighter than steel or wood, but without compromising bending strength, and which is flexibly adaptable to allow construction of a torsionally rigid frame, especially on a modular basis.

A further object is to provide a framework constructed with use of such struts and a wall constructed with the use of the framework, especially a framework and wall capable of disassembly and reassembly. Other objects and advantages of the invention will be apparent from the following description.

According to a first aspect of the present invention there is provided a framework construction strut usable both vertically and horizontally for construction of a framework for a wall, the strut comprising a hollow extrusion provided at one of a first pair of substantially parallel and mutually opposite longitudinal sides with a support face for at least one wall panel and at the other one of those sides with a slot extending over the full length of the strut and serving for reception of fastening means for use in fastening the strut to a support or to another such strut and further provided at each of a second pair of substantially parallel and mutually opposite longitudinal sides substantially perpendicular to the sides of the first pair of sides with a respective longitudinal groove disposed adjacent to the side with the support face and serving for reception of part of a fixing bracket for fixing the strut to another such strut in a butt joint relationship, the extrusion having an intermediate bracing wall extending substantially parallel to the sides of the first pair of sides and at a position spaced from and between the slot and the grooves to brace the sides of the second pair of sides relative to one another and to bound together with the sides of the second pair of sides and the side with the support face a cavity for receiving and concealing another part of such a fixing bracket.

By comparison with struts of folded steel or wood, a strut embodying the present invention, thus a strut in the form of a hollow extrusion, offers the advantage of integrated fastening solutions to enable not only fixing of several such struts together to form a wall framework, especially a framework for a facing or cladding wall, but also attaching of the strut to a support, for example a structural wall, the design of the extrusion being such that fastening means and fixing brackets used for constructing and attaching a framework can be firmly anchored in and at least partly concealed within the strut. The extrusion can be significantly lighter than steel or wood counterparts, while offering comparable or even greater strength in bending by virtue of its hollow form of boxlike shape defined by the pairs of opposite sides in conjunction with the intermediate bracing wall. The last- mentioned fully compensates for any loss of rigidity in compression due to the longitudinal slot along one of the side walls. Such a strut, whether deployed vertically or horizontally, is highly suitable for load-bearing constructional applications and has the advantage that it is optimised for use in both orientations and can be joined to other such struts in butt joint relationship using fixing brackets engaging in either or both of the grooves, fastening means engaging in the slot, or both connecting solutions. The strut can preferably be provided in a single standard length or several standard lengths and in either case cut to a desired final length. Since the slot and grooves are continuous in the strut, reduction of the strut length has no effect on the functionality of the slot and grooves.

For preference, each groove is bounded at each of two mutually opposite longitudinal sides by a respective tolerance lip capable of being reduced in size to widen the groove, which provides a simple means of adjustment to accommodate fixing brackets which may happen to be slightly oversize. Since the lips can be relatively thin, they can be readily locally reduced in size, in the sense of increasing the spacing between them, by grinding, filing or cutting depending on the respective material.

Fixing of the strut to a further such strut may be enhanced if each of the sides of the second pair of sides is provided within the cavity with two spaced-apart longitudinal ribs for positional location therebetween of bracket parts received in the cavity. Such ribs can engage edges of bracket parts, for example bracket arms or limbs, to define a consistent bracket position relative to the strut and to contribute to the rigidity of strut interconnections, in particular by way of butt joints.

In a preferred embodiment, the slot is bounded by flanges which are directed towards the intermediate bracing wall and define therewith a receiving space internally of the strut for captive reception of a component of the fastening means. The fastening means can be, for example, a threaded fastener in the form of a nut and a stud or bolt, in which case the stud or bolt can extend through the slot and the nut can be located, preferably so as to be secure against turning, in the receiving space. Such a fastener can be, for example, a proprietary item in which the nut can be urged against the free edges of the flanges by a spring bearing against the intermediate wall.

In order to provide cross-sectional strength of the extrusion selectively where most needed the cross-sectional thickness of the side with the support face and the parts of the sides with the grooves can be less than that of the rest of the strut. A variable cross-sectional thickness makes it possible to focus strength in the areas where it is needed most while saving material and thus weight in Other areas. The strut is preferably made of aluminium alloy, although other extrudable materials may be possible if requirements relating to strength and bending resistance can be met by, for example, appropriate increase in wall thickness. If the strut is made of alloy, it can be finished with, for example, a polyester- based powder coating.

According to a second aspect of the present invention there is provided a framework comprising a plurality of struts each according to the first aspect of the invention and a plurality of fixing brackets fixing the struts together, wherein at least some of the struts define a frame formed by at least two first ones of the struts arranged to extend substantially parallel to and at a spacing from one another and at least two second ones of the struts arranged to extend substantially parallel to and at a spacing from one another and substantially perpendicular to the first struts, the first struts and the second struts meeting one another at butt joints, and wherein a respective one of the fixing brackets is arranged at each of at least some of the butt joints and has a part received in one of the grooves of one of the struts participating in that joint and a further part received and concealed in the cavity of the other one of the struts participating in that joint, the bracket being fastened to each of those struts.

A framework constructed in this manner may be characterised by a particularly high level of torsional or diagonal rigidity by virtue of the firm interconnections at the butt joints achieved through engagement of the fixing brackets not only in the grooves, but also in the cavities of the struts forming the frame. The fixing brackets, which are concealed partly in the cavities and partly in the grooves, can be secured to the struts by suitable fasteners, such as bolts or set screws. The use of threaded fasteners permits simple assembly and also disassembly as well as reassembly.

In a preferred embodiment of the framework the part of each bracket received in a groove of the struts is mechanically positively located therein, in particular by engagement with or abutment against the sides, for example lips, of the groove. The resulting firm location of the bracket in the respective groove contributes to the mentioned torsional rigidity of the frame. Similarly, the part of each bracket received in a cavity of the struts can be mechanically positively located therein, for example by way of engagement with or abutment against the mentioned longitudinal ribs of the second pair of sides, which in part bound the cavity. This makes a further contribution to frame rigidity.

For preference, at least one of the brackets is substantially‘U’-shaped, the parallel arms of the‘IT being received in a cavity of the struts and the base of the‘U’ being received in a groove of the struts. The U-shaped configuration means that the two arms of the bracket can be fixed to two opposite strut sides, in particular those of the second pair, bounding the cavity. Such a bracket not only provides a firm connection, but also is entirely concealed in the assembled frame. Additionally or alternatively, at least one of the brackets can be of substantially‘F’-shaped configuration, the parallel arms of the‘F’ being received in a cavity of the struts and the upright of the‘F’ being received in a groove of the struts. The arms of this bracket can be fixed in similar manner to those of the U-shaped bracket, but in this instance the upright of the‘F’ - which connects the arms - is longer and extends over a greater length in the groove in which it is received. Accordingly, it can be secured in the groove at two spaced-apart fixing points to provide an even firmer connection.

The framework preferably also includes a plurality of fastening plates each arranged at a respective one of at least some of the butt joints and fastened by fastening means to each of the struts participating in that joint, the fastening means comprising first components extending through the slots of those struts and second components captively received in receiving spaces internally of the struts and co-operating with the first components. The fastening plates provide enhanced security of the strut interconnections at the butt joint locations to achieve even greater torsional rigidity of the frame and strong resistance to lozenging of the frame under load. Depending on location, at least some of the fastening plates may be substantially T-shaped, particularly if intermediate the corners of the frame, or substantially‘L’-shaped if at those corners. The T and ‘L’ shapes of the fastening plates ensure that struts connected together at butt joints incorporating the plates are immovable relative to one another when subjected to the level of loading likely to be encountered in the context of a wall framework

In one constructional format of the framework, the plurality of struts may include struts of shorter length than the first and second struts, the shorter-length struts extending within the frame. The shorter-length struts can provide intermediate bracing and/or attachment points for, for example, sanitary ware of other similarly heavy fixtures.

The present invention also embraces, in a third aspect, an internal facing wall comprising a framework according to the second aspect of the invention and at least one wall panel supported at the support faces of at least some of the struts and attached to at least some of the supporting struts. The weight of such a wall will, to a substantial extent, depend on the weight of the wall panel, with only a smaller proportion of the overall weight being attributable to the framework itself and strut connectors. Accordingly, assuming use of only a moderately heavy panel, the wall constructed with use of that framework can be relatively light, yet rigid.

In an advantageous construction, the wall panel or at least one of the wall panels is attached to the struts by hinges permitting pivotation of the panel relative to the framework. This feature affords convenient access to wiring, pipework and any other fittings at a side of the wall opposite an intended viewing side. Such a hinged wall panel can of course, be releasably secured or latched in a closed position. The wall will normally include a plurality of such wall panels, the framework and wall panels being of modular format. Thus, for example, a framework may typically comprise struts of a given length placed horizontally to create horizontal runs at the top and bottom and further struts placed vertically and connected to the horizontal struts to form a framework of desired height and length, the framework then being clad with an appropriate number of wall panels again of a given dimension. In this way a wall of variable dimensions can be produced in modular manner by aggregation of units, i.e. struts and panels, of entirely or mostly standard sizes, but including reduction of strut length where necessary. Such a wall can be, for example, a wall for a sanitary facility and have mountings at predetermined locations for sanitary units. These units can typically be basins, urinals and cisterns for water closets, provided in any desired arrangement. Basins, urinals and cisterns will have an elevated, cantilever mounting on the struts, which by virtue of their construction from hollow load-bearing extrusions and interconnection by way of the described fixing brackets and fastening means can accept the loading of the units without bending or distortion of the supporting framework.

According to a fourth aspect of the present invention there is provided a method of constructing an internal facing wall for a structural wall of a building, comprising the steps of prefabricating a bespoke facing wall according to the third aspect of the invention at a facility remote from the building, disassembling the facing wall, transporting the disassembled facing wall to the vicinity of the structural wall of the building, reassembling the facing wall and attaching the reassembled facing wall to the structural wall. This procedure allows construction, in factory or workshop conditions, of the facing wall and also provisional equipping with any units, such as sanitary ware, to be supported by or associated with the wall. The assembly can then be dismantled and subsequently erected and reassembled at the installation site without need for any, or at least extensive, manufacturing or building activity at the site beyond attachment to, for example, a supporting wall and connection of services.

A preferred embodiment will now be more particularly described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a plan view of part of a facing wall incorporating two interconnected struts each embodying the invention;

Fig. 2 is a sectional view on the line ll-ll of Fig. 1 ;

Fig. 3 is a scrap perspective view, obliquely from above and behind, of the facing wall of Fig. 1 , in which far the sake of clarity section cross-hatching has been omitted; and

Fig. 4 is a view, to reduced scale, of the entire facing wall in use as a washroom wall, partly from the front (lefthand side) and the back (righthand side).

Referring now to the drawings there is shown in Figs. 1 to 4 part of an internal facing wall 10 which, by way of example, is intended to be erected in front of and attached to a structural wall and to serve as a washroom wall carrying sanitary units such as wash basins, urinals or water closet cisterns. A particular feature of the wall is that it can be prefabricated at a factory from standard components in a modular manner to different dimensions and for different specific purposes, thus in this example provided with and/or equipped to enable functioning of different sanitary units, and then disassembled, transported to the place of installation, reassembled and installed. It will be understood that construction as a washroom wall is merely an example of a wide range of possible uses. However, a feature of the wall 10 is that it is constructed from load-bearing components to be self-supporting and capable of bearing relatively heavy attachments and fixtures, which allows the wall to be employed for purposes beyond mere facing.

The core component of the wall 10 is an elongate strut 11 in the form of a hollow extrusion of light metal, in particular aluminium alloy, of generally rectangular cross-section. A number of the struts 1 1 appropriately disposed in horizontal and vertical orientations in a single plane can be rigidly connected together, as described in more detail further below, to create a frame of a framework 12 forming a skeleton of the wall. Figs. 1 to 3 show merely a small part of such a frame, in particular a segment of a horizontal strut 11a and a segment of a vertical strut 1 1 b, which meet one another in a butt joint relationship. In the illustrated configuration of the struts, an end face of the vertical strut 1 1 b bears against a side of the horizontal strut 1 1 a to form a butt joint, but within the frame the relative disposition of the vertical and horizontal struts at the butt joints can be reversed, i.e. end faces of horizontal struts can bear against sides of vertical struts. For reasons of strength, particularly loading in vertical direction, the frame is preferably formed by horizontal struts at the top and the bottom and vertical struts bearing at their end faces against sides of the horizontal struts, both at the perimeter of the frame and at intervals within the frame.

Each strut has a first pair of parallel and mutually opposite longitudinal sides 13 and a second pair of parallel and mutually opposite longitudinal sides 14 perpendicular to the sides of the first pair. In external cross-section, the strut extrusion is shaped in such a way that in the case of the first sides 13 one of those sides defines a planar support face 13a for a wall panel 15 or wall panels and the other one of those sides 13 has a slot 13b extending over the full length of the strut 1 1 , whereas in the case of the second sides 14 each of those sides is provided over the full length thereof with a respective longitudinal groove 14a adjacent to the first side having the support face. The two grooves are at least substantially the same, in this embodiment identical, and have a constant width and depth so that they are unchanging along the length of the strut. The extrusion is completed by an internally disposed intermediate bracing wall 16 extending parallel to the first sides 13 and between the slot 13b and the grooves 14a, so as to brace the second sides 14 relative to one another and to bound - together with those sides and the first side having the wall panel support face 13a - a cavity 17. The intermediate bracing wall 16 makes up for any loss of compressive strength of the extrusion that might otherwise arise due to the presence of the full-length slot 13b.

The slot 13b serves for reception of fasteners for use in fastening the strut to a support such as the mentioned structural wall or to another such strut and is bounded by flanges 13c directed inwardly of the extrusion towards the intermediate bracing wall 16 so as to define with that wall a receiving space 18 for captive reception of components of the fasteners. In the illustrated example, the fasteners are threaded fasteners each consisting of a male component in the form of a stud or bolt extending through the slot 13b and a female component in the form of a plate nut 19 located in the receiving space 18 and urged against the free edges of the flanges 13c by a compression spring 20. The plate nut 19 is grooved to engage the edges of the flanges 13c so as to be secure against turning when the stud or bolt is screwed into the nut. The plate nut 19 is thus firmly located and captive in the receiving space 18, but in a freely selectable position along the space, i.e. anywhere along the edges of the flanges 13c. Accordingly, one or more fasteners can be provided at any desired locations along the length of the strut 11.

The drawings show, by way of example, two different forms of threaded fastener cooperating with the slot 13c. The two forms of fastener have the same female component and differ only with respect to the male component. The first form of fastener (Fig. 1 ), which is for use in securing the framework 12 to a structural wall, a post or other support and is a proprietary component, comprises a stud 21 which can be screwed at one end portion into an associated plate nut 19 and has at the opposite end an apertured fixing strap 21a. The stud 21 carries a lock nut 22 to enable the stud to be secured iri the plate nut 19 against relative rotation and, under the lock nut 22, a clamping plate 23 bearing against the slotted one of the first sides 13 of the strut 11. The second form of fastener (Fig. 3), for Use in securing a fastening plate 24 to fasten two struts 11 together at a butt joint, comprises a conventional bolt 25 which passes through an aperture in the fastening plate 24 and can be screwed into an associated plate nut 19. The fastening plate 24 can be T-shaped as shown in Figs. 3 and 4 or‘L’ shaped or simply strap-shaped as shown in Fig. 4, the particular shape depending on the task of the plate and position in the framework. A typical wall framework 12, as shown in Fig. 4, may include plates.24 of all three shapes at different locations. As also evident from the drawings, between two and four fasteners of the second form, i.e. plate nut 19 and bolt 25, are associated with each fastening plate 24.

The longitudinal grooves 14a provided in the second sides 14 of the strut 11 each serve for reception of part of a fixing bracket 26 for fixing the strut to another such strut in the butt joint relationship. The fixing bracket 26 can be‘F’-shaped as shown in Fig. 1 or‘U’- shaped (not shown). In the case of the former and with reference to the orientation of the struts 11 shown in Figs. 1 to 3, the parallel arms 26a of the‘F’ are received in the cavity 17 in the vertical strut 11 and indeed mechanically positively located therein. This is achieved by engagement of the edges of each of the two arms 26a of the bracket with, respectively, two spaced-apart longitudinal ribs 14b provided at each of the two mutually facing internal surfaces of the second sides 14 of the strut. The arms 26a are thus held between the ribs 14b so that the struts are prevented from twisting or tilting relative to one another. Similarly, the upright 26b - which here is actually horizontal - of the‘F’ is received in the groove 14a in the mutually adjacent one of the second sides 14 of the horizontal strut 11 and mechanically positively located therein, for which purpose the groove 14a is bounded at its mutually opposite longitudinal sides by tolerance lips 14c directed towards one another and bearing against the edges of the bracket 26. If required, the tolerance lips 14c can be reduced in size, i.e. the extent to which they project towards another, so as to widen the groove 14a in order to ensure that the bracket 26 can snugly fit in the groove in a case where the bracket, specifically the upright 26b of the‘F’, is initially slightly oversize. The bracket 26 is secured in place by, for example, setscrews 27, which are shown in the drawings schematically by thick dashed lines or by circles representing screw heads, in particular a respective setscrew 27 extending through each second side 14 of the vertical strut 11 and the associated one of the parallel arms 26a of the‘F’ of the bracket and two setscrews 27 extending through the upright 26b of the‘F’ of the bracket and the adjacent one of the second sides 14 of the horizontal strut 11 at two spaced-apart points, namely one inside the cavity 17 of the vertical strut 11 and the other at a spacing from that strut. The setscrews 27 can be screwed into nuts (not shown) or simply into threaded bores in the arms 26a of the bracket (in order to secure the arms 26a) or in the strut material (in order to secure the upright 26b). The setscrews can, if desired, have a self-tapping capability.

The‘U’-shaped bracket, which is not shown, can be positioned and fixed in analogous manner to the‘F’-shaped bracket 26, with the sole difference that the base of the‘U’ is not as long as the upright 26b of the‘F’ and accordingly the bracket lies wholly within the cavity 17 of the vertical strut 11 and a national projection of that cavity. In the case of both brackets, the cavity receives and conceals the parallel arms of the‘F’ or‘U’. The rest of the bracket, which is recessed in an adjoining groove 14a, is wholly concealed in that groove.

As shown in Fig. 1 , the cross-sectional thickness of the strut 11 can vary depending on the strength required in different areas, so as to achieve a balance between strength, lightness and minimal consumption of strut material. Specifically, the cross-sectional thickness of the first side 13 with the support face and of those parts of the second sides 14 with the grooves 14a is less than in the rest of the strut. The greatest strength, i.e. greatest cross- sectional thickness, of the strut is consequently focused in the area where the struts are connected by the relatively heavy-duty fastening plates 24 and are fixed to the structural wall or other support, thus an area of maximum application of load to a frame constructed from the struts and erected as part of a facing wall 10.

A facing wall 10 constructed with use of the struts 1 1 described in the foregoing is illustrated in Fig. 4. The specific form of wall 10 shown in Fig. 4 is merely an arbitrary example of disposition and interconnection of the struts 11 , the layout of which will necessarily vary from one wall to the next. Vertically and horizontal oriented struts 11 are disposed, in butt joint relationship, to define a frame of desired dimensions and are connected together by the fastening plates 24 and fixing brackets 26 to form a framework 12, which in turn is clad with the wall panels to form a rigid, self-supporting facing wall. The framework 12 includes shorter-length struts positioned to provide internal bracing and also, in the case of the illustrated wall, mounting points for fittings in the form of sanitary units. A basin 28 is shown by way of an example of such a unit. The struts 11 also serve as attachment points and/or conduits for feed pipes, drain pipes, wiring and other elements of services. The wall panels 15 are attached directly to the struts 1 1 , preferably by way of hinges or folding stays, so that access to a space between the facing wall and supporting structural wall is conveniently available. Such a hinge can take the form of, for example, a support bracket 29 (Fig. 1 ) mounted in a selected one of the grooves 14a of the horizontally oriented struts and a pivot pin (not shown) attached to the back of one of the wall panels 15 and pivotably retained in an opening in the support bracket 26; a hinge of that kind will be provided at both the bottom and the top of each wall panel concerned. Such a folding stay (not shown) can be, for example, a pantograph-type of stay of the kind used as a friction stay for opening casement windows, in which case a bar or channel with sliding blocks for arms of the stay can be mounted in a selected one of the grooves 14a and a distal end of one of the arms can be pivotably attached to the wall panel. As evident from Fig. 4, the wall panels 15 are of divided construction in height so as to be of a manageable size, particularly with regard to weight and ease of pivoting.

A facing wall 10 constructed in this manner is of modular construction, in particular based on largely standard forms of framework struts 1 1 , fastening plates 24, fixing brackets 26 and wall panels 15 to create a wall of any desired height and length on a grid-like modular basis. A particular advantage, apart from the light weight and strength resulting from the hollow extrusions used as the core elements of the framework 12, is the capability of constructing the facing wall 10 on a bespoke basis in a factory equipped with cutting/sawing and drilling equipment, provisional attachment of sanitary or other fittings to the constructed wall or segments of the wall during construction, disassembly of the wall simply by release of the various threaded fasteners 19, 25 and 27 connecting the wall components together, transport of the wall components in manageable sizes to the place of installation, reassembly of the wall, attachment of units and associated fittings and securing the facing wall to the structural wall, posts or other support. Manufacturing processes, as such, at the place of installation are entirely or largely eliminated.

Claims

1. A framework construction strut usable both vertically and horizontally for construction of a framework for a wall, the strut comprising a hollow extrusion provided at one of a first pair of substantially parallel and mutually opposite longitudinal sides with a support face for at least one wall panel and at the other one of those sides with a slot extending over the full length of the strut and serving for reception of fastening means for use in fastening the strut to a support or to another such strut and further provided at each of a second pair of substantially parallel and mutually opposite longitudinal sides substantially perpendicular to the sides of the first pair of sides with a respective longitudinal groove disposed adjacent to the side with the support face and serving for reception of part of a fixing bracket for fixing the strut to another such strut in a butt joint relationship, the extrusion having an intermediate bracing wall extending substantially parallel to the sides of the first pair of sides and at a position spaced from and between the slot and the grooves to brace the sides of the second pair of sides relative to one another

I

and to bound together with the sides of the second pair of sides and the side with the support face a cavity for receiving and concealing another part of such a fixing bracket.

2. A strut according to claim 1 , wherein each groove is bounded at each of two mutually opposite longitudinal sides by a respective tolerance lip capable of being reduced in size to widen the groove.

3. A strut according to claim 1 or claim 2, wherein each of the sides of the second pair of sides is provided within the cavity with two spaced-apart longitudinal ribs for positional location therebetween of bracket parts received in the cavity.

4. A strut according to any one of the preceding claims, wherein the slot is bounded by flanges which are directed towards the intermediate bracing wall and define therewith a receiving space internally of the strut for captive reception of a component of the fastening means.

5. A strut according to any one of the preceding claims, wherein the cross-sectional thickness of the side with the support face and the parts of the sides with the grooves is less than that of the rest of the strut.

6. A strut according to any one of the preceding claims, wherein the strut is made of aluminium alloy.

7. A framework comprising a plurality of struts each according to any one of the preceding claims and a plurality of fixing brackets fixing the struts together, wherein at least some of the struts define a frame formed by at least two first ones of the struts arranged to extend substantially parallel to and at a spacing from one another and at least two second ones of the struts arranged to extend substantially parallel to and at a spacing from one another and substantially perpendicular to the first struts, the first struts and the second struts meeting one another at butt joints, and wherein a respective one of the fixing brackets is arranged at each of at least some of the butt joints and has a part received in one of the grooves of one of the struts participating in that joint and a further part received and concealed in the cavity of the other one of the struts participating in that joint, the bracket being fastened to each of those struts.

8. A framework according to claim 7, wherein the part of each bracket received in a groove of the struts is mechanically positively located therein.

9. A framework according to claim 7 or claim 8, wherein the part of each bracket received in a cavity of the struts is mechanically positively located therein.

10. A framework according to any one of claims 7 to 9, wherein at least one of the brackets is substantially‘U’-shaped, the parallel arms of the‘U’ being received in a cavity of the struts and the base of the‘U’ being received in a groove of the struts.

1 1. A framework according to any one of claims 7 to 10, wherein at least one of the brackets is substantially‘F’-shaped, the parallel arms of the‘F’ being received in a cavity of the struts and the upright of the‘F’ being received in a groove of the struts.

12. A framework according to any one of claims 7 to 11 , further comprising a plurality of fastening plates each arranged at a respective one of at least some of the butt joints and fastened by fastening means to each of the struts participating in that joint, the fastening means comprising first components extending through the slots of those struts and second components captively received in receiving spaces internally of the struts and co-operating with the first components.

13. A framework according to claim 12, wherein at least some of the fastening plates are substantially T-shaped.

14. A framework according to claim 12 or claim 13, wherein at least some of the fastening plates are substantially‘L’-shaped.

15. A framework according to any one of claims 7 to 14, wherein the plurality of struts includes struts of shorter length than the first and second struts, the shorter-length struts extending within the frame.

16. An internal facing wall comprising a framework according to any one of claims 7 to 15 and at least one wall panel supported at the support faces of at least some of the struts and attached to at least some of the supporting struts.

17. A facing wall according to claim 16, wherein the wall panel or at least one of the wall panels is attached to the struts by hinges permitting pivotation of the panel relative to the framework.

18. A facing wall according to claim 16 or claim 17, comprising a plurality of such wall panels, the framework and wall panels being of modular format.

19. A facing wall according to claim 18, wherein the facing wall is for a sanitary facility and has mountings at predetermined locations for sanitary units.

20. A method of constructing an internal facing wall for a structural wall of a building, comprising the steps of prefabricating a facing wall according to any one of claims 16 to 19 at a facility remote from the building, disassembling the facing wall, transporting the disassembled facing wall to the vicinity of the structural wall of the building, reassembling the facing wall and attaching the reassembled facing wall to the structural wall.