AU2004202984B2

AU2004202984B2 - Spacer for concrete form work and reinforcing

Info

Publication number: AU2004202984B2
Application number: AU2004202984A
Authority: AU
Inventors: Thomas Carl Kudelka; Peter William McLeod; Andrew Emden O'Loughlan
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2003-06-30
Filing date: 2004-06-30
Publication date: 2010-09-09
Anticipated expiration: 2024-06-30
Also published as: AU2004202984A1

Description

AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: SPACER FOR CONCRETE FORM WORK AND REINFORCING Applicant: Modfix Australia Pty Ltd The following statement is a full description of this invention, including the best method of performing it known to me: 1 2 SPACER FOR CONCRETE FORM WORK AND REINFORCING BACKGROUND OF THE INVENTION Field of the Invention 5 This invention relates to a spacer for relative positioning of formwork components and reinforcing material of poured concrete structures. The spacer is applicable for use with formwork for voided raft slabs such as those for building foundations, and it will be convenient to hereinafter disclose the invention in relation to that exemplary application. However, it is to be 10 appreciated that the invention is not limited to that application. Description of the Prior Art One type of form work used for voided concrete slabs involves an array of spaced apart blocks, boxes or other bulk form voider elements, typically known as "pods", rafted together with metal reinforcing bar and mesh, and around and 15 over which concrete is poured and allowed to set in order to form the concrete slab. In one arrangement, pods are square shaped in plan view and measure about 1090 x 1090 mm. Since the pods are lost to the slab, they are usually composed of cardboard, plastics such as polystyrene foam, or other inexpensive and light weight materials of adequate strength to support the 20 reinforcing material and concrete until set. The reinforcing material is installed in trenches or channels defined between the spaced apart pods, and over the upper surface of the pods. In order to maintain the pods in accurate relative location one to another, as well as the reinforcing material in accurate location relative to the pods, while the 25 concrete is poured and sets, bar chairs or spacers are installed between the pods and reinforcing material. Different spacers have been developed for installation at the intersections of the channels. Those spacers act to maintain the channel spacing between the pods defining the intersections, and also locate the reinforcing material laid in the channels relative to the pods and the 30 underlying foundation footing. Examples of channel spacers are disclosed in Australian patent 591816, and patent applications 199910040 and 200157850. Each of those spacers has a fame of generally cruciform configuration for positioning within a channel intersection, and the frame has surfaces for engaging a corner of each of the W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 3 pods defining that intersection so as to relatively locate the pods. A support up stands from the frame and has a U-shaped slot for receiving and supporting reinforcing rods therein. A problem with these prior spacers is that it can be difficult to position the 5 reinforcing material in the support slot. In that regard, reinforcing mesh of nominally the same size and dimensions supplied by different manufacturers can have slight rod spacing and alignment inconsistencies, so that the rod is not readily located in the spacer slots in edge channel applications. Moreover, the rod is sometimes not fully accommodated in those slots. As a result, the reinforcing material may require 10 significant effort for proper positioning in the channels. A further problem with some prior spacers is that they may not permit free flow of concrete through and about the spacer. Although the spacers superficially appear to have an open matrix appearance, when installed the pod array and reinforcing material may enclose the spacer to an extent that restricts openings and 15 clearances intended for concrete access through and about the spacer. That is particularly apparent immediately beneath the supports for the reinforcing material. As a consequence, concrete voids can be created within and about the spacers which can lead to structural deficiencies within the slab. 20 SUMMARY OF THE INVENTION It is an object of the present invention to provide a simple spacer with improved capability of supporting reinforcing material. It is a further object of the present invention to provide a simple spacer that reduces the prospects of concrete voids being created within and about the spacer. 25 In accordance with the present invention, there is provided a spacer for relative positioning of formwork components and reinforcing material of a poured concrete structure, the spacer including: a frame having engaging surfaces for engaging formwork components so as to maintain the components in relatively spaced apart relation; and support means extending from the frame for supporting 30 reinforcing bar in a location spaced relative to the formwork components, wherein the frame includes a base through which the spacer bears on a foundation footing for the formwork components in positioning the formwork components and 4 reinforcing bar, and spacing members suspended outwardly in cantilever arrangement from the base so as to be in spaced relation from the foundation footing, the spacing members providing said engaging surfaces; and wherein the support means is in the form of a single support wall having a single central recess 5 for receiving the reinforcing bar so as to positively locate said bar relative to the spacer and formwork components, the support wall extending diagonally across and upstanding from the base, the support wall having an edge in which the recess opens, the edge being curved toward the recess at either side of the recess for guiding said reinforcing bar received on the edge toward the recess for location 10 therein, the recess being shaped and sized to receive the reinforcing bar oriented longitudinally and/or transversely of the base. Preferably, the frame base has one or more base members defining a base perimeter. The base member(s) preferably bear on the foundation in positioning the formwork components and reinforcing material. The base preferably has an at least 15 substantially hollow interior. In one preferred form, the or each base member is a base wall. There may be four such walls providing a frame base of quadrangular shape in plan view. The or each base wall has opposite longitudinal edges. One of the edges of the base wall, or of at least some of the base walls, bears on the foundation in positioning the 20 formwork components and reinforcing material, in this form. In one preferred form, the one edge of the or each base wall is uninterrupted along its length. The or each one edge bears continuous along its length on the foundation in use of the spacer. In one preferred form, the or each base wall has openings interrupting the other edge along its length, those openings providing for 25 flow of concrete into the interior of the base. Preferably, the engaging surfaces are arranged so as to engage the formwork components in face-to-face relation at corner regions adjacent a channel defined between the components. Preferably, the spacing members extend laterally from the base members for 30 projecting along channels defined between the formwork components. In one preferred form, the spacing members includes spacing arms projecting from the base wall(s). Each spacing arm has at least one engaging 5 surface for engaging a respective surface of a formwork component, in this form. In one preferred form, each spacing member includes a pair of spacing arms projecting from the base wall(s). Each spacing arm provides one engaging surface. In one preferred form, the spacing arms of each spacing member extend 5 from the base walls at or adjacent corners of the base, and parallel to one another. Moreover, those spacing arms are spaced from one edge of the base wall(s) so as to define a clearance between the spacing arms and foundation on which the one edge(s) bear. Preferably, the spacing members include bracing webs extending between 10 the spacing arms in spaced relation to the base. In one preferred form, each spacing member has a bracing web extending between free ends of the spacing arms. Those bracing webs extend parallel to the base walls from which the respective spacing arms project, in one preferred form. In one preferred form, that support wall is elongate and extends longitudinally 15 diagonally across the base between opposite corners defined between adjacent base walls, In one preferred form, the edge on either side of the recess is radiused or arched from opposite ends of the support wall to the recess, In one preferred form, the support recess is a slot in the support wall. The 20 slot is shaped and sized to receive a reinforcing bar or rod extending along either of two mutually perpendicular axes, in this form. Preferably, the support means includes a bracing web extending across the base. That web connects to the support wall and base so as to brace the support wall against deflection in use. In one preferred form, the bracing web extends 25 diagonally across the base, perpendicular to the support wall, between opposite corners defined between adjacent base walls. More preferably, the bracing web is straight and planar, and extends in a plane that passes through the recess, the bracing web extending at a level beneath the recess to avoid interference with reinforcing bar or rod extending therethrough. 30 There is also disclosed a spacer extension for use with the above spacer. The extension is connectable to the frame, and has an elongate spacer member for extending 6 longitudinally from the frame for engagement with an edge formwork component for locating the spacer in spaced relation to the edge formwork component. Preferably, the spacing member includes a spacing stem. The spacer extension preferably includes a connecting member at one 5 end of the spacing member for connecting the spacer extension to the frame. In one preferred form, the connecting member includes a connecting clip for removably clipping the spacer extension to a bracing web of one of the spacing members. The connecting clip includes a groove or slot for clippingly receiving the bracing web there along, in this form. 10 Preferably, the spacer extension includes an engaging member at one end of the spacing member for abutting against the edge formwork component. In one preferred form, the engaging member includes an engaging foot. The engaging foot is elongate and depends from the end of the spacing member and may bear on the foundation footing. Moreover, the engaging foot has an 15 engaging surface for abutting edge formwork component in face-to-face engagement. Preferably, the spacer extension includes a support member at one end of the spacing member for supporting the spacer extension on the foundation footing. In one preferred form, the support member includes a support foot. 20 The support foot in elongate and depends from the connecting clip for bearing on the foundation foot. This invention is further disclosed herein with reference to the spacer in a normal building use orientation on a horizontally extending footing, and terms such as "lower" and "upper" should be construed in the light of that orientation. 25 However, it is to be appreciated that other orientations may be equally possible and that consequential changes in terms such as those above may be required in the light of those other orientations for a proper and complete understanding of the invention. 30 DESCRIPTION OF THE DRAWINGS The following description refers to a preferred embodiment of the spacer and spacer extension of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the spacer and spacer extension are illustrated in that preferred W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 7 embodiment. It is to be understood that the spacer and spacer extension are not limited to the preferred embodiment as hereinafter described and as illustrated in the drawings. In the drawings: 5 Fig. 1 is a perspective view of a spacer according to a preferred embodiment of the present invention in use relatively positioning formwork components and reinforcing material on a foundation footing; Fig. 2 is a top plan view of the spacer of Fig. 1; Fig. 3 is a side view of the spacer of Fig. 1; 10 Fig. 4 is a side view of part of the spacer of Fig. 1 with a spacer extension according to one preferred embodiment of the present invention connected thereto and in use relatively positioning formwork components and reinforcing material on a foundation footing; Fig. 5 is a top plan view of the spacer extension of Fig. 4 connected to the 15 spacer; Fig. 6 is a side view similar to Fig. 4 but with a spacer extension according to another preferred embodiment of the present invention; and, Fig. 7 is a top plan view of the spacer extension of Fig. 6 connected to the spacer. 20 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring initially to Fig. 1 there is generally shown a spacer 1 for relative positioning of formwork components F (only two of which are shown for 25 purposes of clarity) and reinforcing material R on a surface S of a foundation footing D for a poured concrete structure (not shown). The spacer 1 and formwork components F bear on upper surface S, and the formwork components F also abut against the spacer 1 so as to position the components F in a spaced apart relationship which defines a channel C therebetween. 30 Reinforcing material R such as bar or mesh (depending on the location of the spacer 1 and channel C), in turn, bears on the spacer 1. The spacer 1 is particularly applicable for use with voided raft slabs in which the formwork components F include an array of pods P spaced apart in side-by-side relation on the foundation footing D so as to define therebetween a W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 8 series of intersecting channels C. In use in this application, the spacer 1 is positioned at an intersection I of two channels C, and engages the pods P adjacent to and defining the intersection. In an arrangement where those channels C (internal channels C') cross one another (as shown in Fig. 1), then 5 corner regions of four pods will together define the intersection I. In an alternative arrangement (as shown in Fig. 4), the channels C (an channel C' internal and an edge channel C") intersect at a T so that the corner regions N of two pods P, and a side region of another pod or some other form work component, such as edge member E, will together define the channel 10 intersection 1. It will be convenient to further describe the spacer 1 in relation to that exemplary formwork, although it should be appreciated that the spacer 1 may have broader applications. The spacer 1 is shown in more detail in Figs. 2 and 3, and includes a frame 2 having engaging surfaces 3 for engaging the pods P so as to maintain 15 them in their spaced apart relation. The spacer 1 also includes support means 4 extending from the frame 2 for supporting the reinforcing bar or mesh R in a location relative to the pods P. The spacer frame 2 is of an open or skeletal construction to facilitate concrete flow therethrough in use. The frame 2 has a base 5, through which 20 the spacer 1 bears on the foundation footing D in use, and spacing members 6 extending therefrom and providing the engaging surfaces 3. The engaging surfaces 3 are arranged so as to engage the pods P at their corner regions N adjacent the channel intersection 1. That engagement is face-to-face engagement. 25 The frame base 2 has a plurality of base members 7 defining a perimeter of the base 5 and a substantially hollow interior. Each base member 7 is elongate and has opposite longitudinal edges 8, 9 respectively defining lower and upper open ends of the base 5, having regard to the orientation of the spacer 1 in use. In use, the base 5 upstands on a foundation footing D with the 30 base members 7 extending upright, the lower edge 8 of the base members 7 bearing on the footing D and the upper edge 9 being spaced therefrom. In this embodiment, each base member 7 is a base wall 10. Moreover, the frame base 5 is square shaped in plan view, and has four walls 10 arranged to define the base perimeter with corners 11. W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 9 The lower bearing edges 8 of the base walls 10 are uninterrupted along their length. The upper edges 9 of the base walls 10 may also be uninterrupted along their length. However, as shown they are interrupted or discontinuous as a result of openings 12 in the walls 10 extending to the upper edges 9. Those 5 openings 12 extend substantially along each base wall 10 so as to provide access for concrete therethrough into the base interior. The spacing members 6 extend laterally from the base members 7. The arrangement is such that, in use, the spacing members 6 project along the channels C between the pods P, with the engaging surfaces 3 engaging the 10 pods P at their corner regions N in order to maintain the pod spacing and thus channel dimensions. In this embodiment, the spacer 1 has four spacing members 6 for projecting in respective opposite directions along two crossing channels C. The spacing members 6 extend at spaced apart angles about the spacer base 5 the 15 same as the intersecting angle of the channels C. Thus, for example, where the channels C intersect at 90* (as shown) then, the spacing members 6 are spaced apart about the base 5 also at 900. The spacing members 6 include spacing arms 13 projecting from the base walls 10. Each arm 13 has at least one engaging surface 3 for engaging a 20 respective surface of a pod P defining the channel C into which the arm 13 projects. The engaging arm surfaces 3 engage the pod surfaces in face-to-face relation. Each spacing member 6 includes a pair of spacing arms 13 extending from a respective base wall 10, each arm 13 providing one engaging surface 3. 25 The arms 13 of each spacing member 6 extend parallel to one another. Moreover, the spacing arms extend from the base walls 10 at or adjacent corners 11 of the base 5. Thus, a spacing arm 13 from each adjacent spacing member 6 extends from a respective base corner 11 at 90* to one another. The spacing arms 13 have a pair of opposed longitudinal edges 14, 15. 30 Moreover, the arms 13 are straight and of planar configuration providing straight and planar engaging surfaces 3. The arms 13 are spaced from the lower bearing edges 8 of the base walls 10. Thus, in use, the spacing arms 13 are spaced above the bearing edges 8. W:\Tresse\SpecisSpacer4ConcreteReinforcing(2).23.06.04.doc 10 In this way, a clearance is defined beneath the arms 13 for passage of concrete thereunder. The spacing arms 13 project perpendicularly from the base walls 10 adjacent the upper edge 9 of those walls 10. The upper edge 15 of the arms 13 5 extends level or flush with the upper edge 9 of the base wallslO. The lower edge 14 of the arms 13 extends from the base walls 10 about mid way between the upper and lower edges 9, 8 thereof. The spacing members 6 include bracing webs 16 extending between the spacing arms 13 so as to enhance their rigidity against deflection under weight 10 of the concrete and force of abutting pods P, particularly during a concrete pour. As shown, a respective web 16 extends between the two spacing arms 13 of each spacing member 6. Each spacing member 6 has a bracing web 16 extending between the spacing arms 13 in spaced relation to the base 5. The webs 16 extend between 15 what would otherwise be free ends of the spacing arms 13 remote from the base walls 10. Those webs 16 extend parallel to their respective base walls 10. The bracing webs 16 are also spaced above a level of the lower edges 8 of the base walls 10. The webs have opposed lower and upper edges17, 18 which extend flush or level with the lower and upper edges 14, 15, respectively, 20 of the arms 13 between which they extend. As shown, each spacing member 6 is square U-shaped in plan, with the spacing arms 13 forming the legs of the U, and the bracing web 16 forming the bottom of the U. The spacing members 6 may each have the same length, i.e. project the 25 same distance from the base 5. However, in the preferred embodiment shown, the spacing members 6 have different lengths. In particular, two opposed members 6 intended to project along one intersecting channel C are longer than the other two opposite spacing members 6 intended to project along the other intersecting channel C. This arrangement will enable the spacer 1 to be used at 30 T intersecting channels C', C" in which the edge channel C" continuing through the intersection I varies in width, as will be explained in more detail hereinafter. The support means 4 includes a support member 19 providing a recess 20 for receiving reinforcing bar or mesh rod R so as to positively locate that bar or W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 11 mesh R relative to the spacer 1 and formwork components F such as pods P and edge form member E. The support member 19 outstands from the frame base 5. Moreover, the support member 19 extends across the base 5, and connects to the base 5 members 7 defining the base periphery. The recess 20 is located in the support member 19 above the base 5. The support member 19 includes a support wall 21. The support wall 21 extends between and upstands from the base walls 10. The support wall 21 is elongate with opposed lower and upper longitudinal 10 edges 22, 23, and extends longitudinally across the base 5. As shown, the support wall 21 is straight and planar, and extends diagonally across the base 5 between opposite base corners 11. The support wall 21 is spaced from the lower bearing edges 8 of the base walls 10 so that there is an underlying clearance for passage of concrete. To 15 that end, the lower edge 22 of the support wall 21 extends adjacent the upper edges 9 of the base wall 5, 10, whilst the support wall upper edge 23 is spaced there above. The support recess 20 is a slot 24 in the support wall 21. The slot 24 opens upwardly onto the upper edge 23 of the support wall 21. Moreover, the 20 slot 24 is located substantially centrally over the base 5. In this embodiment, the slot 24 is shaped and sized to receive therein a reinforcing bar or mesh rod R extending in the direction of the spacing arms 13. In this way, in spacer use, the slot 24 will be able to receive and support reinforcing bar or rod R extending along either of the intersecting channels C. 25 The slot 24 is shaped and sized to at least substantially receive two reinforcing bars or rods R extending one each along a respective channel C and crossing through the slot 24. Those bars or rods R will be positioned one on top of the other. Thus, the lower bar or rod R will be positioned entirely within the slot 24, and the upper bar or rod R will be positioned either entirely or 30 substantially within the slot 24. In the exemplary application of the spacer 1, the slot 24 will be dimensioned to fully receive two Y16 reinforcing bars or rods R. As shown, the slot 24 is of generally square U-shape. That slot 24 is of a width that will loosely receive reinforcing bar or rod R therein. W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.08.04.doc 12 The support member 19 is configured to facilitate positioning of reinforcing bar or mesh rod R therein. To that end, the upper edge 23 of the support wall 21 is profiled or shaped to guide reinforcing bar or rod R toward the slot 24 and thereby facilitate receipt therein. 5 In this embodiment, the upper edge 23 of the support wall 21 at least adjacent the slot 24 is convexly curved downwardly toward the slot 24. In this way, bar or mesh rod R received on the edge 23 will tend to be guided toward the slot 24. As shown, the upper edge 23 on either side of the slot 24 is radiussed or arched downwardly from opposite ends of the support wall 21 to 10 the slot 24. The support means 4 includes bracing webs 25, 26 to brace the support member 19 against deflection under weight of the concrete and reinforcing material, particularly during a concrete pour. As shown, bracing web 25 extends from the support member 19 to the 15 base members 7. As shown, additional bracing webs 26 are provided between the diagonal bracing web 25 and the support wall 21 in order to further stabilise the support wall 21 relative to the base 5. That bracing web 25 is elongate, and extends across the base 5, 20 connecting to the support wall 21 and base walls 10. Specifically, that bracing web 25 is straight and planar, and extends diagonally across the base 5, perpendicular to the support wall 21, between opposite base corners 11. The bracing webs 25, 26 have upper longitudinal edges 27 extending flush with or beneath a bottom of the support slot 24. With this arrangement, a 25 clearance is maintained beneath the support means 4 for flow of concrete therebeneath and, at the same time, the bracing webs 25, 26 do not interfere with receipt of reinforcing bar or mesh rod R in the support slot 24. In this embodiment, the spacer 1 is formed in one piece. That may be achieved by moulding the spacer 1 from plastics material. 30 In the exemplary application, the base 5 has an outside dimension of about 105 x 105mm, and the longer spacing members 6 are about 90mm long, whilst the shorter spacing members 6 are about 60mm long. In use of the invention in the exemplary application, a plurality of pods P will be placed on a prepared foundation footing D in a predetermined spaced W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 13 apart array as part of formwork for a building foundation. As the pods P are progressively placed on the footing D, spacers 1 are positioned at the corner regions N of adjacent pods P, in abutting engagement so as to maintain the pods P in spaced apart relationship and define intersecting channels C 5 therebetween. As placement of the pods P and spacers 1 proceeds, or following their placement, reinforcing bar and mesh R can be laid along the internal and edge channels C', C", respectively on top of the spacers 1. The bar or mesh R is arranged so that bar or mesh rods are received in the spacer support slots 24. 10 Where the bar or mesh R extends along intersecting internal channels C' then bars R will cross one on top of the other in the slots 24, as shown in Fig. 1. When the bar or mesh R is initially dropped into the channels C it may not be immediately received in the slots 24, but will bear upon the curved upper edge 23 of the support wall 21 of the spacers 1. In that position, the bar or 15 mesh rod can be easily guided and manoeuvred toward and into the slots 24. The weight of the bar or rod will assist in that final positioning. Where the pods P are placed adjacent an edge of the formwork, an edge channel C" will be defined between those pods P and an edge form member E such as a board or plank. Spacers 1 can be placed at the T intersections of that 20 edge channel C" and the internal channels C' defined between adjacent pods P. The two different lengths of spacing arms 13 will allow the spacer 1 to accommodate two different edge channel C" widths. Alternatively, where the edge channel C" is of a width greater than that able to be spanned by the spacer 1 then, as shown in Figs. 4 to 7, a spacer 25 extension 28 may be provided so as to fit between the spacing member 6 and the edge form member E. In this arrangement, the spacer extension 28 will extend from the spacer 1 and abuttingly engage with the edge form member E, and so maintain the spacer 1 and pods P in spaced apart relation to the edge form member E. 30 Figs. 4 and 5, and Fig. 6 and 7, show different embodiments of the spacer extension 28. In both embodiments, the spacer extension 28 includes an elongate spacing member 29 for extending longitudinally between the spacing member 6 of the spacer 1 and the edge form member E. That spacing member 6 has opposite ends which, in use of the spacer extension 28, are W:\TresseSpecis\Spacer4ConcreteReinforcing(2).23.06.04.doc 14 located adjacent the spacing member 6 of the spacer 1 and the edge form member E, respectively. In each embodiment, the spacing member 29 includes a spacing stem 30. The spacing stem 30 may be of any suitable length having regard to the width 5 of the edge channel C" across which it will extend. Each spacer extension 28 has a connecting member 31 at one end of the spacing member 29 for connecting to a spacing member 6 of the spacer 1, so that the spacer extension 28 can project laterally therefrom across the edge channel C". The connecting member 31 removably connects the spacer 10 extension 28 to the spacing member 6 of the spacer 1. The connecting member 31 includes a connecting clip 32 for clipping the spacer extension 28 to the bracing web 16 of a spacing member 6 of the spacer 1. The connecting clip 32 includes a groove or slot 33 for clippingly receiving the web 16 there along. In Figs. 4 and 5, the connecting clip 32 clips on top of the 15 web 16, whilst in Figs. 6 and 7 the clip 32 clips to the underside of the web 16. The spacer extension 28 also has an engaging member 34 at the other end of the spacing member 29 for abutting against the edge form member E. That engaging member 34 has an engaging surface 35 for abutting the edge form member E in face-to-face engagement. 20 The engaging member 34 includes an engaging foot 36. The engaging foot 36 is elongate and depends from the other end of the spacing stem 30. The engaging foot 36 may be of a depending length so as to bear on surface S of the footing D (as shown in broken outline in Fig. 4 and full outline in Fig. 6). The foot 36 extends perpendicular to the stem 30. 25 The spacer extension 28 and spacer 1 are configured so that the spacer extension 28 extends generally co-planar with the spacing member 6 to which it is connected. In particular, an upper surface 37 of the spacer extension 28 extends flush with the upper edge 18 of the bracing web 16 to which it is connected. That can be achieved, in the embodiment of Figs. 4 and 5 by 30 lowering the upper edge 18 of the bracing web 16 relative to the upper edges 15 of the adjacent spacing arms 13, at least in the region at which the connecting clip 32 is connected thereto. To that end, the bracing web 16 is provided with a recess 38 extending along a region thereof and opening onto the upper edge 15, that recess 38 receiving the connecting clip 32 when the W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 15 spacer extension 28 is connected thereto. The recess 38 is not required with the spacer extension 28 embodiment of Figs. 6 and 7. In the embodiment of Figs. 6 and 7, the spacer extension 28 also has a support member 39 at the one end of the spacing member for supporting the 5 spacer extension 28. The support member 39 includes an elongate support foot 40 depending from the connecting clip 32. The support foot 40 is of a length so as to bear on the surface S of the footing D in the same manner as engaging foot 36. In these embodiments, the spacer extension 28 is formed in one piece. 10 That may be achieved by moulding the spacer extension 28 from plastics material. When the spacers 1 and spacer extensions 28 are in position at the channel T intersection I, reinforcing mesh R can be laid along the edge channel C" in the same manner as reinforcing bar R is laid along the internal channels C' 15 defined between the pods P. Again, reinforcing mesh rods will be received in the support slots 24. Bar and mesh rods extending along the continuing edge channel C" and the terminating internal channel C' between pods P may again cross one another in the slots 24. The spacer of the present invention facilitates accurate positioning of 20 reinforcing material in concrete building foundations, and can therefore lead to cost savings in foundation construction. In addition, the open configuration of the spacer improves opportunities for concrete access into and around the spacer during concrete pour. As a result, concrete voids within or around the spacer are minimised. 25 Finally, it is to be understood that various alterations, modifications and/or additions may be made to the spacer without departing from the ambit of the present invention as defined in the claims appended hereto. W:\Tresse\Specis\Spacer4ConcreteReinforcing(2).23.06.04.doc 16 The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the 5 common general knowledge in the field of endeavour to which this specification relates. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a 10 stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims

1. A spacer for relative positioning of formwork components and reinforcing material of a poured concrete structure, the spacer including: 5 a frame having engaging surfaces for engaging formwork components so as to maintain the components in relatively spaced apart relation; and support means extending from the frame for supporting reinforcing bar in a location spaced relative to the formwork components, wherein the frame includes a base through which the spacer bears on a 10 foundation footing for the formwork components in positioning the formwork components and reinforcing bar, and spacing members suspended outwardly in cantilever arrangement from the base so as to be in spaced relation from the foundation footing, the spacing members providing said engaging surfaces; and wherein the support means is in the form of a single support wall 15 having a single central recess for receiving the reinforcing bar so as to positively locate said bar relative to the spacer and formwork components, the support wall extending diagonally across and upstanding from the base, the support wall having an edge in which the recess opens, the edge being curved toward the recess at either side of the recess for guiding said reinforcing bar received on the 20 edge toward the recess for location therein, the recess being shaped and sized to -receive the reinforcing bar oriented longitudinally and/or transversely of the base.

2. A spacer as claimed in claim 1, wherein the frame base has one or more 25 base members defining a perimeter of the base, the base member(s) bearing on the foundation in positioning the formwork components and reinforcing material, and the base has an at least substantially hollow interior.

3. A spacer as claimed in claim 2, wherein the or each base member is a 30 base wall having opposite longitudinal edges, one of the edges of the base wall or of at least some of the base walls bearing on the foundation in positioning the formwork components and reinforcing material. 18

4. A spacer as claimed in claim 3, wherein the one edge of the or each base wall is uninterrupted along its length, and the or each one edge bears continuous along its length on the foundation in use of the spacer. 5

5. A spacer as claimed in claim 3 or 4, wherein the or each base wall has openings interrupting the other edge along its length, the openings providing for flow of concrete into the interior of the base. 10

6. A spacer as claimed in any one of claims 2 to 5, wherein the frame base is quadrangular in plan view with four base walls arranged to define the base perimeter.

7. A spacer as claimed in any preceding claim, wherein the engaging 15 surfaces are arranged so as to engage the formwork components in face-to-face relation at corner regions adjacent a channel defined between the components.

8. A spacer as claimed in any one of claims 2 to 6, or claim 7 when appended thereto, wherein the spacing members extend laterally from the base 20 members for projecting along channels defined between the formwork components.

9. A spacer as claimed in claim 3 or in any claim appended thereto, wherein the spacing members include spacing arms projecting from the base wall(s), 25 each spacing arm having at least one engaging surface for engaging a respective surface of a formwork component.

10. A spacer as claimed in claim 9 wherein each spacing member includes a pair of spacing arms projecting from the base wall(s), each spacing arm providing 30 one engaging surface.

11. A spacer as claimed in claim 10 when appended to claim 6 or any claim 19 appended thereto, wherein the spacing arms of each spacing member extend from the base walls at or adjacent corners of the base, and parallel to one another. 5

12. A spacer as claimed in any one of claims 9 to 11, wherein the spacing arms are spaced from the one edge of the base wall(s) so as to define a clearance between the spacing arms and foundation on which the one edge(s) bear. 10

13. A spacer as claimed in any one of claims 9 to 12, wherein the spacing members include bracing webs extending between the spacing arms in spaced relation to the base.

14. A spacer as claimed in claim 13 when appended to claim 11 or any claim 15 appended thereto, wherein each spacing member has a bracing web extending between free ends of the spacing arms, the bracing webs extending parallel to the base walls from which the respective spacing arms project,

15. A spacer as claimed in any preceding claim, wherein the support wall is 20 elongate and extends longitudinally diagonally across the base between opposite corners defined between adjacent base walls.

16. A spacer as claimed in any preceding claim, wherein the support wall is spaced from the one edge of the base wall(s) so as to define a clearance 25 between the support wall and foundation footing on which the one edge(s) bear(s) for flow of concrete therethrough.

17. A spacer as claimed in any preceding claim, wherein the support wall is straight and planar throughout its extent. 30

18. A spacer as claimed in any preceding claim, wherein the edge on either side of the recess is radiused or arched from opposite ends of the support wall to 20 the recess.

19. A spacer as claimed in any one of claims 17 to 23, wherein the support means includes a bracing web extending across the base, and connecting to the 5 support wall and base so as to brace the support wall against deflection in use.

20. A spacer for relative positioning of formwork components and reinforcing material of a poured concrete structure, substantially as hereinbefore described with reference to what is shown in the accompanying drawings.