Abstract:
An elongated hollow mould for the integral formation of a raised sill or hob on the surface of a cast-in-situ concrete building slab, said mould comprising two generally parallel, continuous side panels joined in fixed spatial relationship at their upper and lower edges by spacer elements which permit the entry of concrete from above and the passage of concrete there through to formwork below upon which said slab is to be formed, thereby making the concrete within said filled mould contiguous with that of said concrete slab beneath; said mould being supported upon a plurality of discrete chairs, each said chair comprising two narrow, parallel, vertically oriented side panels joined at their lower ends by a transverse bottom part fixed to said formwork, said mould being supported in a said chair by a height-adjustable transverse bridge fixed to said chair side panels.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/AU2011/000792, filed Jun. 28, 2011, which claims priority to Australian Application No. AU2010902877, filed Jun. 29, 2010. This application claims priority to both International Application No. PCT/AU2011/000792 and Australian Application No. AU2010902877. The PCT/AU2011/000792 application and the AU2010902877 are hereby incorporated by reference into this application. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable to this application. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    This invention relates generally to the provision, as part of the building construction process, of sills or hobs for the fixing of windows, curtain walls and the like to cast-in-situ concrete slabs. More particularly, it relates to moulds for the casting of such sills or hobs onto or integrally with cast in-situ concrete building slabs. 
         [0005]    2. Description of the Related Art 
         [0006]    Any discussion of the related art throughout the specification should in no way be considered as an admission that such related art is widely known or forms part of common general knowledge in the field. 
         [0007]    Particularly in the construction of multi-story buildings, it is common to provide raised sills or hobs of some form to cast in-situ concrete slabs. Such sills or hobs act as supports for building elements such as window frames, curtain wall panels and the like, providing a watertight barrier beneath such building elements to prevent the ingress of rain water and condensation. Said building elements may incorporate lower frames or sills that bear directly upon and are sealed to a supporting surface such as a cast in-situ concrete slab. These commonly take the form of simple or complex metal sections or solid timber sections. In other applications, separate sills or hobs of similar form are sealing fixed to a said supporting surface and said building elements are fixed to and supported by said sills or hobs. In yet other applications, concrete sills or hobs are formed on said cast in-situ concrete slabs to support said window frames, curtain wall panels and the like. In these applications, long box moulds which are more or less open at the top and bottom are fixed in appropriate positions to concrete slabs, filled with concrete and the concrete allowed to cure. Said sills or hobs are then waterproofed appropriately and said building elements then fixed to them. The separate forming of said sills or hobs on cast in-situ concrete slabs is inefficient and time consuming, requiring the re-attendance of several building trades personnel to a building site to accurately measure up and fix said moulds in position and then to fill them with concrete. Additionally, irregularities in the trowelled surfaces of said cast in-situ concrete slabs may require the removal of concrete in order for said moulds to be set at the correct level. When it is considered that a multi-story building may require several thousand lineal meters of such sills or hobs, the magnitude of the inefficiency and loss of time will be appreciated. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The object of the present invention is to provide a system that permits the installation of sills or hob moulds to be integrated into the process of fixing steel reinforcement preliminary to the pouring of concrete slabs, and the filling said sill or hob moulds to be integrated into the process of in-situ casting of concrete building slabs. According to the present invention, sill or hob moulds in the form of long boxes more or less open at the top and bottom are installed during the process of installing reinforcing bar. Said moulds are supported from formwork upon chairs which permit the height of said moulds to be adjusted such that their lower edges are set at the surface level of the finally cast slab. Fabricated short mould sections are used to join straight runs of said moulds end to end and at directional changes through angles of 90°, 45° or angles of other magnitude. During casting of the parent concrete building slab, said moulds are simultaneously filled with concrete and trowelled off to a level surface. The concrete of the sill or hob so created is thus integral with that of said concrete building slab and is thus much less prone to water infiltration. Various methods are provided to positively prevent water infiltration. Said moulds are made in a variety of cross-sectional shapes and different methods are provided for attaching them to said chairs and adjusting their heights. Provision is made for said sill or hob moulds to be made regularly curved to different radii or in other irregular alignments. 
         [0009]    There has thus been outlined, rather broadly, some of the features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and that will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction or to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0011]      FIG. 1  is a transverse cross-sectional view of a sill or hob mould supported on a chair fixed to formwork, the mould filled with concrete and the concrete building slab cast beneath it. 
           [0012]      FIG. 2  is a fragmentary transverse cross-sectional view of the upper part of one embodiment of said sill or hob mould. 
           [0013]      FIG. 3  is a view from above of said sill or hob mould of  FIG. 2 . 
           [0014]      FIG. 4  is a fragmentary view from above of one embodiment of the transverse bottom part of a chair of the present invention. 
           [0015]      FIG. 5  is a fixing disk employed with chairs of the embodiment depicted in  FIG. 4 . 
           [0016]      FIG. 6  is a view from above of a 90° corner join straight runs of said sill or hob mould. 
           [0017]      FIG. 7  is a transverse cross-sectional view of another embodiment of said sill or hob mould depicting two embodiments of said chair. 
           [0018]      FIG. 8  is a transverse cross-sectional view of an embodiment of said sill or hob mould intended to be extruded in continuous lengths from a suitable thermoplastic polymer or light metal alloy material. 
           [0019]      FIG. 9  is a transverse cross-sectional view of an embodiment of said sill or hob mould made with an asymmetric shape. 
           [0020]      FIG. 10   a  is a fragmentary transverse cross-sectional view of means to join spacers to the side panels of said sill or hob moulds. 
           [0021]      FIG. 10   b  is a fragmentary transverse cross-sectional view of the joining means of  FIG. 10   a  following their setting. 
           [0022]      FIG. 11  is a fragmentary transverse cross-sectional view of means to join said sill or hob moulds to said chairs. 
           [0023]      FIG. 12  is a fragmentary transverse cross-sectional view of means to join said sill or hob moulds to said chairs or to join spacers to the side panels of said sill or hob moulds. 
           [0024]      FIG. 13   a  is fragmentary transverse cross-sectional view of means to join spacers to the side panels of said sill or hob moulds. 
           [0025]      FIG. 13   b  is a fragmentary transverse cross-sectional view of the joining means of  FIG. 13   a  following their setting. 
           [0026]      FIG. 14  is a fragmentary transverse cross-sectional view of means to join said sill or hob moulds to said chairs. 
           [0027]      FIG. 15  is a fragmentary transverse cross-sectional view of alternative means to join said sill or hob moulds to said chairs. 
           [0028]      FIG. 16  is a fragmentary view from above of one embodiment of spacers inserted between side panels of said sill or hob moulds. 
           [0029]      FIG. 17  is a fragmentary view from above of another embodiment of spacers inserted between side panels of said sill or hob moulds. 
           [0030]      FIG. 18  is a fragmentary transverse cross-sectional view of means to join spacers to side panels of said sill or hob moulds. 
           [0031]      FIG. 19  is a side view in skeletal form of an embodiment of a chair to support said sill or hob moulds which permits precise height adjustment. 
           [0032]      FIG. 20  is a fragmentary, transverse cross-sectional view of clamping means to attach a chair to reinforcing bar. 
           [0033]      FIG. 21  is a transverse cross-sectional view of an alternative embodiment of chair comprising threaded rods supported from a base plate. 
           [0034]      FIG. 22  is a fragmentary, transverse cross-sectional view of an alternative embodiment of clamping means to attach a chair to reinforcing bar. 
           [0035]      FIG. 23  is a fragmentary, transverse cross-sectional view of alternative means of attaching a threaded rod of a chair to its supporting base plate. 
           [0036]      FIG. 24  is a view from above of an embodiment of the plate of a rod and plate-type chair. 
           [0037]      FIG. 25  is a fragmentary transverse cross-sectional view of adjustable means to fix said sill or hob mould to the rods of a rod and plate-type chair. 
           [0038]      FIG. 26  is a view from above of an alternative embodiment of rod and plate-type chair. 
           [0039]      FIG. 27  is a fragmentary, transverse cross-sectional view of an alternative embodiment of clamping means to attach a chair to reinforcing bar. 
           [0040]      FIG. 28  is a fragmentary, transverse cross-sectional view of means allowing lateral positional adjustment in fixing said sill or hob mould to a chair. 
           [0041]      FIGS. 29   a ,  29   b ,  29   c  and  29   d  are transverse cross-sectional views of alternative forms of chair. 
           [0042]      FIG. 30  is a transverse cross-sectional view of a chair incorporating the section of  FIG. 29   d  to support a sill or hob mould at an of adjustable height. 
           [0043]      FIG. 31  is a face view of a bifurcated attachment tab arrangement. 
           [0044]      FIG. 32  is a face view of the reverse side of a base plate or sill or hob mould at the point of attachment of a chair incorporating the section of  FIG. 29   d . 
       
    
    
       [0045]    The various figures are drawn to different scales and no inference should be drawn from this. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    With reference to  FIGS. 1 ,  2  and  3 , sill or hob mould  1  is supported upon chair  2  which is, in turn, fixed to formwork  3 . Said sill or hob mould comprises side panels  4  joined in spatial relationship at their upper edges by a plurality of spacer clips  5 . Said side panels are joined in fixed spatial relationship at their lower edges by spacer piece  6  being tack-welded to upstanding flanges  7  formed on lower transverse flanges  8 . Conveniently, said spacer piece takes the form of a short section cut from a continuous length of rectangular tube section. With additional reference to  FIGS. 2 and 3 , the upper edges of said side panels are turned through 90° to create upper transverse flanges  9  which are engaged by tabs  10  of said spacer clips to retain said clips in position. Said upper edges of said side panels are maintained in spatial relationship by their abutment with the inner surfaces of downturned edge flanges  11  of said spacer clips and the said engagement of said upper transverse flanges by tabs  10 . Upstanding flanges  7  formed on lower transverse flanges  8  and upper transverse flanges  9  act to stiffen, respectively, the lower and upper edges of said sill or hob mould side panels. 
         [0047]    Chair  2  is fixed to formwork  3  by nails  12  or other suitable fastenings being driven through suitable apertures in transverse bottom part  13  of said chair. Chair side panels  14  pass upwardly with a lateral separation such as to provide sliding contact of their inner surfaces with the outer surfaces of said sill or hob mould side panels. Transverse bridge  15  fixed to said chair side panels with suitable fastenings  16  supports said sill or hob mould at the desired height above said formwork. Said side panels of said sill or hob mould are secured to said chair side panels by suitable fastenings passing through both. Said sill or hob mould, said chair and the area above said formwork to the desired level are then filled with concrete  18 , thereby embedding said chair, and slab surface  19  and the upper surface of the concrete filling of said sill or hob mould are trowelled off to create the desired surface finishes. The fixing of bridge  15  and said sill or hob mould to said chair and the fixing of said chair to said formwork is normally carried out by the appropriate trades during the fixing of reinforcement bar, plates or mesh within said formwork. The height of said bridge is normally set to position the lower edge of said sill or hob mould at the surface of said concrete slab when poured. In alternative embodiments (not shown), the lower edge of said sill or hob mould is set above or below said slab surface when poured. In the preferred embodiment, where a large number of said chairs are required to have said bridges and said sill or hob moulds fixed to them, suitable jigs are provided to position said components appropriately, one to another, and to install said fastenings. Said fastenings optionally take the form of pop rivets, conventional screws or bolts screwed into tapped holes, conventional self-tapping screws, self-piercing and self-drilling/self-tapping screws, self-piercing rivets, hot-melt adhesives, quick-setting two-part adhesives, spot welding or any other suitable fixing means. When the concrete of said slab has cured, said formwork is stripped away and fastenings  12  are hammered flat or preferably cut off or ground away with an angle grinder or the like. In an alternative embodiment (not shown), sill or hob mould side panels  4  are attached to the outer edges of lower transverse flanges  8  by simple hinges, the arrangement permitting said sill or hob moulds to be opened out and shipped flat. When required for use, said side panels are pivoted upwardly through approximately 90° and a plurality of spacer clips  5  is slidingly engaged with upper transverse flanges  9  of said side panels, thereby retaining said sill or hob moulds in a fixed rectangular form. 
         [0048]    With reference to  FIGS. 4 and 5 , a said chair in fixed into place on said formwork by the sprigs  22  of a fixing plate  21  being driven through suitable apertures  20  provided in transverse bottom part  13  of said chair. Said fixing plate is die-punched from a suitable metal sheet material and radially arranged projections  22  are turned through 90° to create attachment sprigs. The use of said fixing plate facilitates the accurate fixed location of said chair, said fixing plate being installed by a single blow from a suitable punch with a round, flared head, a suitable aperture being provided in bridge  15  (as depicted in  FIG. 1 ) to provide access for said punch. In alternative embodiments (not shown), said chairs are fixed to said formwork using any suitable nails, screws or adhesives. 
         [0049]    With reference to  FIG. 6 , two runs  23 ,  24  of said sill or hob mould are joined by joining member  25 . Said joining member is fabricated from suitable sheet material, having the same width and depth as said sill or hob mould. In the preferred embodiment, said sill or hob mould side panels are provided at their upper and lower edges with transverse flanges (typically depicted as  9  and  8  in  FIG. 7 ). Also in the preferred embodiment, the inner edges of said transverse flanges are turned through a further 90° to form inwardly directed flanges parallel to said side panels (depicted as  7  in  FIG. 1 ). The ends of transverse spacers  26  are turned through 90° and spot welded to said upstanding flanges and maintain said side panels in fixed spatial relationship. Oblique strap  29  is spot welded to upper and lower transverse flanges  8  to strengthen the corner of said joining member. Transverse straps  27  are spot welded to said upper and lower transverse flanges to maintain a precise geometry of said sill or hob mould at the joining point, said sill or hob mould runs abutting said joining member at points  28 . Doublings (not shown) are fixed to the inner surfaces of said joining member and extend outwardly to enter and abut the inner surfaces of the ends of said sill or hob mould side panels with a suitable degree of overlap. The fixing of said doublings to said side panels of said sill or hob moulds using suitable fastenings is the method of joining said sill or hob mould runs to said joining member. Said joining member is supported from said formwork by a chair having a square or equi-armed, L-shaped base, one corner or the apex  30  of which, respectively, is exposed. In the preferred embodiment, said corner or apex is fixed to said formwork (depicted as  3  in  FIG. 1 ) using a fixing plate (depicted as  21  in  FIG. 5 ). In alternative embodiments, any conventional fixing means are employed. Upwardly extending chair side panels  14  are fixed to or formed on the edges of said chair in appropriate positions such that their internal surfaces make sliding contact with the external surfaces of said sill or hob mould side panels. Bridges (depicted as  15  in  FIG. 1 ) are fixed to said chair side panels to support said joining member at an appropriate height above said formwork. Said chair side panels are fixed to said sill or hob mould side panels in the manner described in relation to  FIG. 1 . Said joining members are optionally fabricated in different forms to join lengths of said sill or hob mould at a range of angles. Said joining members and said sill or hob mould are optionally made from a variety of materials, including light metal alloys, steel alloys and engineering polymers, where necessary, appropriately treated against corrosion. 
         [0050]    With reference to  FIG. 7 , in an alternative embodiment, said sill or hob mould is made with symmetrical side panels, the upper and lower edges of which are turned through 90° to create upper and lower transverse flanges  8 ,  9 . The ends of transverse spacers  32 ,  33  are turned through 90° and spot welded to said side panels. In an alternative embodiment (not shown), said spacers are made in continuous, zigzag-type form with small flats parallel to said sill or hob mould side panels provided between each angled part, said flats being spot welded to said side panels. Said embodiment is suited for continuous production in which said side panels are formed up from continuous lengths of flat, rolled metal strip and straightened, said side panels are brought together with said continuous, zigzag-type spacers between them and said spacers are spot welded to said side panels. Depending upon the dimensions of said sill or hob mould, the vertical width of said transverse spacers and said zigzag-type spacers falls in the range 10 millimeters to substantially the same height as said sill or hob mould. In an alternative embodiment (not shown), said sill or hob mould is formed up from continuous lengths of rolled metal strip in a generally U-shaped form and panels of suitable size are punched or otherwise cut out from the lower transverse panel to create voids separated by narrow transverse strips. In this embodiment, for stiffening purposes, the upper edges of said side panels of said sill or hob mould are at least turned through 90° to form transverse flanges (depicted as  9  in  FIG. 2 ). In the preferred embodiment, robotic spot welding means are employed to fix said spacers to said sill or hob mould side panels. Said chair is made with two overlapping or telescopic side panels  14 ,  34 , the abutting surfaces of which are in sliding contact. Said side panels are made with coincident slotting and a bolt  35  passes through said slotting such that, when nut  37  is tightened onto the threaded end of said bolt, said side panels are captured between the ends of crush tube  36 , the head of said bolt and said nut. The upper ends of chair side panels  34  are turned through 90° to create transverse fixing flanges  31 . Said sill or hob mould is fixed to said chair by suitable fastenings  39  passing through lower transverse flanges  8  and transverse fixing flanges  31 . The height of said sill or hob mould above formwork  3  is set by loosening nut  37 , slidingly adjusting the height of said chair and re-tightening said nut. In an alternative embodiment (not shown), separate guide slots are provided in one pair of said chair side panels ( 14 ,  14  or  34 ,  34 ) which are engaged by suitable guide buttons provided on the other pair of said chair side panels, said embodiment acting to maintain said side panels in alignment during their said sliding adjustment. In another alternative embodiment (not shown), only one pair ( 14 ,  14  or  34 ,  34 ) of said chair side panels is slotted and said bolt is retained in suitable apertures in said other pair of side panels. Chair side panels  14  are fixed to formwork  3  by suitable fastenings (typical positions indicated in broken line as  38 ) driven through suitable apertures in transverse bottom part  13 . In an alternative embodiment, a transverse partition (position depicted in broken line as  40 ) is provided joining the upper ends of chair side panels  34  and a transverse partition (position indicated in broken line as  41 ) is provided joining the lower ends of chair side panels  14 . Height adjustment screws (positions indicated in broken line as  42 ) pass between said partitions, in the preferred embodiment, said screws being of the inter-screw type in which a male screw of conventional form with an extended threaded part engages a female (tubular) screw with an extended threaded part. Shortening of said screws (by deepening the engagement of the male screw with the female) acts to increase the height of said sill or hob mould above said formwork. In an alternative embodiment, said screws are long screws of conventional form and their heads are rotationally captured at one said partition, the other ends of said screws engaging nuts fixed to the other said partition. Rotation of said screws in the appropriate sense increases or decreases the height of said sill or hob mould above said formwork. The height of said sill or hob mould is normally set to position its lower edge at the finished surface of said slab when poured. In alternative embodiments (not shown), the lower edge of said sill or hob mould is set above or below said slab surface when poured. With additional reference to  FIG. 28 , in an alternative embodiment, chair  2  is made with a transverse top part  95  joining the upper edges of side panels  14  and said chair is fixed to formwork  3  by fastenings passing through suitable tabs or flanges  93  formed on the lower edges of said side panels. Said transverse top part is made with transversely arranged slots (not shown) which permit the lateral position of sill or hob mould  1  to be adjusted before said sill or hob mould is fixed to said chair with suitable fastenings (typical positions indicated as  94 ). In the preferred embodiment, said fastenings take the form of bolts passing through any of a plurality of suitable apertures (not shown) in narrow, transversely arranged strips  96  joining the lower edges of said sill or hob mould side panels, through said slots and screwably tightened into nuts (not shown) positioned beneath said chair transverse top part. 
         [0051]    With reference to  FIG. 8 , said sill or hob mould is extruded in a continuous length from a thermoplastic polymer material or light metal alloy material. Said extruded section comprises two side panels  43  connected at the lower end by a transverse web which is punched or otherwise cut out to create voids  46  separated by narrow transverse strips. Longitudinal rails  44 ,  45  are provided along the upper and lower inner edges of said side panels and channels  47 ,  48  are provided in said rails. Said channels are made with an approximately circular cross-sectional shape to which access is gained via slots. Said slots are orientated, respectively in relation to channels  47 ,  48 , upwardly and downwardly. Said slots taper inwardly to a width being approximately 10% to 20% smaller than the diameter of said channels and, as such, form constricted entries to said channels. Said chair side panels (not shown) are made with their upper edges substantially cylindrical in form and with a diameter able to be neatly accommodated within channels  48 . Said sill or hob mould is fixed to said chair by said chair side panel upper edges being forced through said slots to frictionally engage channels  48 . Closure  49  is made with shallow longitudinal rails  50  along each edge, the free edges of said rails being made in substantially cylindrical form with a diameter able to be neatly accommodated within channels  47 . Said closure is fixed to said sill or hob mould by said rail edges being forced through said slots to frictionally engage channels  47 . In an alternative embodiment (not shown), suitable apertures are punched or otherwise cut out from said closure to create voids separated by narrow transverse strips. In another alternative embodiment (not shown), said sill or hob mould is extruded in a single section, with side panels  43  connected at their upper and lower ends by transverse webs which are both punched or otherwise cut out to create voids separated by narrow transverse strips. In another alternative embodiment (not shown) said chair side panels are made from metal sheet and their upper edges are made into a substantially cylindrical form by rolling or by fixing a wire along said edges, the diameter of said rolling or said wire being such as to be neatly accommodated within channels  48 . 
         [0052]    With reference to  FIG. 9 , said sill or hob mould is made in asymmetric cross-sectional form, with a first flat face  52  and a second face  53  shaped to suit a particular application. In the embodiment shown, said second face is made concave with said mould increasing in width downwardly to suit the mounting of a hospital wall in which vinyl floor tiles are curved to pass from the floor surface to the wall surface. The arrangement is intended to improved hygiene by eliminating the difficult-to-clean zone normally existing at the junction of a wall with a floor surface. The upper edges of said side panels are turned through 90° to create upper transverse flanges  54  and transverse or zigzag-type spacers  57  of the type described in relation to  FIG. 7  are spot welded to said side panels. Longitudinally arranged angles  55 ,  56  are spot welded to the lower inner edges of said side panels and transverse or zigzag-type spacers  58  of the type described in relation to  FIG. 7  are spot welded to said angles. Curved side panel  53  is extended vertically downwards to create apron  59  such that, when said sill or hob mould is embedded in the surface of a concrete building slab (typical surface level of said slab indicated as  19 ), said apron forms a positive moisture barrier. 
         [0053]    With reference to  FIG. 10   a , the lower edge of said sill or hob mould side panel  4  is turned through 90° to create lower transverse flange  8 . Tab  61  is spot welded at its lower end to said side panel. Flat  60  of a zigzag-type spacer  33  of the type described in relation to  FIG. 7  abuts said side panel. With additional reference to  FIG. 10   b , said tab has been bent downwardly and against said flat, thereby fixing said spacer to said side panel. 
         [0054]    With reference to  FIG. 11 , the lower edges of said sill or hob mould side panel side panel  4  of have been turned through approximately 180° to create channels  62  with lipped, constricting edges  63 . The upper edges of chair side panels  64  are made with substantially cylindrical edges  66  which are turned through approximately 180° at bends  65 . In the preferred embodiment, said chair side panels are made from metal sheet and their upper edges are made into substantially cylindrical form by rolling or by fixing of a wire along said edges, the diameter of said rolling or said wire being such as to be neatly accommodated within channels  62 . Said sill or hob mould is fixed to said chair side panel edges by edges  66  being forced past constricting edges  63  to be frictionally captured within channels  62 . The turned ends  60  of transverse spacer  33  (or flats of zigzag-type spacers of the type described in relation to  FIG. 7 ) are spot welded to said sill or hob mould side panels. In an alternative embodiment (not shown), part of said lower edges of said sill or hob mould side panels of suitable width are turned upwardly and tightly through 180° and approximately half of the upturned part is then turned downwardly through 180° to create downwardly orientated channels with constricting edges of the type depicted in  FIG. 11 . The upper edges of said chair side panels are made rolled or wired as described in relation to  FIG. 11 , said edges being of a diameter as may be neatly accommodated within said channels. Said sill or hob mould is fixed to said chair by said rolled or wired edges being forced past said constricting edges to be frictionally captured within said channels. 
         [0055]    With reference to  FIG. 12 , short, downwardly projecting parts of the lower edges of said sill or hob mould side panels  4  are double folded to create a plurality of more or less triangular sections  68 . Short upwardly projecting parts of the upper edges of said chair side panels are double folded to create a plurality of more or less triangular sections  69  able to be neatly accommodated within sections  68 . Said sill or hob mould is fixed to said chair side panels by sections  69  being interdigitated between sections  68 , the former then being displaced laterally to enter and be frictionally captured within the latter. In an alternative embodiment (not shown), the turned ends  70  of transverse spacer  33  (or flats of zigzag-type spacers of the type described in relation to  FIG. 7 ) are made with downwardly extending parts which are double folded into more or less triangular sections able to be frictionally captured within sections  68  in the manner described. 
         [0056]    With reference to  FIG. 13   a , the lower edges of said sill or hob mould side panels  4  are double folded to form lower transverse flanges  72  with short lengths of upstanding flange  73  formed on them. The turned ends  70  of transverse spacers  33  (or flats of zigzag-type spacers of the type described in relation to  FIG. 7 ) are made with short lateral extensions  71  formed on their lower edges. With additional reference to  FIG. 13   b , lengths of upstanding flange  73  have been folded down to capture short lateral extensions  71 , thereby fixing said transverse spacers to said side panels. 
         [0057]    With reference to  FIG. 14 , the lower edges of sill or hob mould side panels  4  are turned inwardly through 90° and approximately half of said turned part turned outwardly through 180° to create outwardly orientated attachment channel  74 . The upper edges of said chair side panels are treated in a reciprocal way to create inwardly orientated attachment channel  76 . Said sill or hob mould is fixed to said chair by the free end  77  of said chair side panel upper edge being accommodated within attachment channel  74  and the free end of sill or hob mould side panel lower edge  78  being accommodated within attachment channel  76 . The turned ends  70  of transverse spacers  33  (or flats of zigzag-type spacers of the type described in relation to  FIG. 7 ) are spot welded to said sill or hob mould side panel. 
         [0058]    With reference to  FIG. 15 , the lower edges of said sill or hob mould side panels are turned through 90° to create lower transverse flange  79 . The upper edges of said chair side panels are turned through 90° to create attachment flanges  80 . Said sill or hob mould is fixed to said chair by the abutting said lower transverse flange and attachment flange being clamped together by screw means  82  or a plurality of suitably spaced clamps  81 . The turned ends  70  of transverse spacers  33  (or flats of zigzag-type spacers of the type described in relation to  FIG. 7 ) are spot welded to said sill or hob mould side panel. 
         [0059]    With reference to  FIG. 16 , the side panels  4  of said sill or hob mould are joined at their upper and lower edges by a continuous length of zigzag-type spacers of the type described in relation to  FIG. 7 , said spacers being attached to said side panels as described in relation to  FIGS. 13   a  and  13   b . In this embodiment, flats of said spacers are provided with short lateral extensions  71  formed on their lower edges, short upstanding flanges  73  formed on the inner edges of lower transverse flanges  72  being folded down to capture said short lateral extensions. Said embodiment is suited for continuous production in which said side panels are formed from rolled metal strip and straightened, said side panels are brought together with said continuous, zigzag spacers between them and said spacers are fixed in the manner described to said side panels. In an alternative embodiment (not shown), said spacers are made in the form of a continuous sinusoidal curve and are clipped into place in the manner described in relation to this Figure or are spot welded into place at the points of contact with said side panels. 
         [0060]    With reference to  FIG. 17 , side panels  4  of said sill or hob mould are joined by a plurality of transverse spacers  26 , the turned ends  70  of which are spot welded to the upper and lower edges of said side panels. Said embodiment is suited for continuous production in which said side panels are formed up from flat, rolled metal strip and straightened, said side panels are brought together with said transverse spacers between them and said spacers are spot welded to said side panels. 
         [0061]    With reference to  FIG. 18 , the lower and upper edges of sill or hob mould side panels  4  are turned through two 90° folds to form lower and upper transverse flanges  77 , each having short upstanding or downwardly directed (as appropriate) flanges  76  formed on them. Clips  74  are folded over the turned ends  70  of transverse spacers  33  (or flats of zigzag-type spacers of the type described in relation to  FIG. 7 ) and lateral extensions  75  of said clips are positioned to abut said lower or upper (as appropriate) transverse flanges. Upstanding or downwardly directed (as appropriate) flanges  76  are then folded inwardly to capture said turned ends of transverse spacers  33  (or flats of zigzag-type spacers of the type described in relation to  FIG. 7 ), thereby joining said sill or hob mould side panels one to another. 
         [0062]    With reference to  FIG. 19 , sill or hob mould  1  is supported at either side upon parallelogram mechanisms formed from upper straps  84 ,  85 ,  86  the upper ends of which are pivotally joined to the lower edges of said sill or hob mould at pivots  78  positioned on each side of said sill or hob mould and pivotally joined to lower straps  87 ,  88 ,  89  at the ends of transverse nut bar  82 , at laterally located pivots  92  and at transverse bearing bar  83 . Said lower straps are pivotally joined to formwork  81  at pivots  79 . Links  91  on either side maintain said nut bar and pivots  92  in fixed spatial relationship. Threaded rod  90  is rotationally captured in a medially positioned bearing (not shown) in said bearing bar and knob  80  is provided to turn it. Said threaded rod passes between laterally located pivots  92  and its distal end is screwably engaged with a medially positioned nut (not shown) in said transverse nut bar, rotation of said threaded rod in the appropriate direction acting to draw said bearing bar and said nut bar closer together or to increase their separation, thereby increasing the height of said sill or hob mould above said formwork of reducing said height. In the preferred embodiment, said straps are made from a stiff metal section and said pivots are made tight with no free play, thereby minimizing any tendency for said sill or hob mould to sway or otherwise deviate from its desired position. The advantage of the said embodiment is its ability to provide precise height adjustment of said sill or hob mould. In the preferred embodiment, pivots  79  are fixed in common to a plate which is, in turn, fixed to said formwork. 
         [0063]    With reference to  FIG. 24 , in an alternative embodiment, a chair to support said sill or hob mould comprises base plate  97  to which is fixed two, parallel, threaded supporting rods  98  of suitable length orientated normal to said base plate. Parallel slots  99  are provided in said base plate. 
         [0064]    With additional reference to  FIG. 20 , in an alternative embodiment, base plate  97  is made with one or more slots  99 . Clamp  107  comprises flat base part  100  on one end of which is formed supporting piece  101 . Fixing screw  103  passes through a said slot and through medially positioned aperture  102  in said flat base part and its threaded part is screwably engaged with the complementary thread of a suitable aperture (not shown) provided in jaw  104 . One end of said jaw is formed into tongue  105  which passes through a suitable aperture positioned towards the free end of said supporting piece. With said fixing screw loosened, said clamp may be slidably positioned along slot  99  of plate  97  and a reinforcing bar  106  may be positioned between adjacent faces of said flat base part and said jaw. Tightening of said fixing screw simultaneously locks said clamp to said plate and seizes said reinforcing bar between said flat base part and said jaw. 
         [0065]    With reference to  FIG. 21 , in an alternative embodiment, a chair to support said sill or hob mould comprises base plate  97  to which are fixed two, parallel, threaded supporting rods  98  of suitable length orientated normal to said base plate. One or more slotted apertures  108  are provided in said base plate and suitable fastenings passing through said apertures are employed to fix said base plate to supporting bars (not shown) which are, in turn, fixed to reinforcing bars (not shown) by a variety of fixing means (not shown). Said slotted apertures permit positional adjustments of said base plate to be made before said base plate if fixed to said supporting bars. In other alternative embodiments (not shown), said chairs comprising base plate and parallel, threaded supporting rods are fixed to said formwork by means of suitable fastenings passing through slotted openings in said baseplate. In these embodiments, said slotted openings permit positional adjustment of said chair prior to tightening of said fastenings. 
         [0066]    With reference to  FIG. 22 , in an alternative embodiment, the base plate  97  of a said chair is provided with one or more slots  99  from which clips  109  are supported by the screwable engagement of the threads of their fixing screws  110  with complementary threads of a bore  112  provided in attachment boss  111 . Said fixing screws pass through said slots and, with said fixing screws loosened, said clips may be positioned to permit them to engage and be frictionally attached to reinforcing bars (not shown). Tightening of said fixing screws acts to fix said clips to said base plate and, thereby, to fix said base plate to said reinforcing bar. 
         [0067]    With reference to  FIG. 23 , in an alternative embodiment, base plate  97  of a said chair is made with one or more slots  113 . Threaded rods  114  of said chair are fixed to said base plate by upper nuts  117  being screwably displaced on the threading of said rods against lower nuts  115 . Suitable shoulders  116  of said lower nuts engage said slots, thereby preventing said lower nuts from turning during tightening of said upper nuts. Obviously, the height of a said threaded rod on said base plate may be adjusted by screwably displacing said upper and lower nuts on said threaded rods. 
         [0068]    With reference to  FIG. 26 , in an alternative embodiment, a chair to support said sill or hob mould comprises base plate  97  to which are fixed two, parallel, threaded supporting rods  98  of suitable length orientated normal to said base plate. Suitable apertures  118  are provided in said base plate to facilitate a flow of concrete through said base plate. Suitable fixing apertures  119  are provided around the periphery of said base plate and said base plate is secured to reinforcing bar (not shown) by wire ties passed through said fixing apertures, around said reinforcing bar and the ends twisted together and tightened. 
         [0069]    With reference to  FIG. 27 , in an alternative embodiment, the base plate  97  of a said chair is provided with upstanding edge flanges  120  provided with longitudinally orientated slots  127 . Clips  128  are supported from said edge flanges by their fixing screws  121  passing through said slots, through spacer tubes  122  and through attachment webs  123  of said clips such that their threaded parts screwably engage and are tightened into complementary threads in nuts  124 . In the preferred embodiment, said clips are of the larger alligator type. With said fixing screws loosened, said clips may be positioned on said edge flanges to permit them to engage and be attached to reinforcing bars (not shown). Tightening of said fixing screws acts to fix said clips to said base plate edge flanges and, thereby, to fix said base plate to said reinforcing bar. Where the height of said base plate is required to be adjusted in relation of said reinforcing bar, said fixing screws are loosened, said clips are partially released from said reinforcing bar and said clips are rotated on said fixing screw as required to perform said height adjustment. Said clips are then permitted to engage said reinforcing bar and said fixing screws are re-tightened. 
         [0070]    With reference to  FIG. 25 , in an alternative embodiment, sill or hob mould  1  is supported on threaded supporting rods  98  fixed to a base plate (not shown). Threads of nuts  129  are screwably engaged with complementary threads of said supporting rods and tubular projections  130  formed on the upper ends of said nuts pass upwardly through suitable apertures  132  provided in narrow, transversely arranged strips  96  joining the lower edges of said sill or hob mould side panels  4 . Dished, metal spring washers  131  are pressed over said tubular projections with small sprigs (not shown) formed around their central apertures engaging the external surfaces of said tubular projections, thereby retaining said spring washers in place and which, by urging said transversely arranged strips against shoulders  133  of said nuts, act to retain said sill or hob moulds in the correct vertical attitude on said supporting rods. In the preferred embodiment, said threading of said supporting rods is made coarse and said nuts are formed from a suitable thermoplastic polymer material providing a firm frictional engagement with said threading. Also in the preferred embodiment, the upper ends of said tubular projections are made hexagonal or other shape intended for engagement by a suitable tool employed to turn said nuts on said supporting rods. Also in the preferred embodiment, said tool is a tube spanner. 
         [0071]    In alternative embodiments (not shown), the rods of said base plate and rod-type chair are made plain and unthreaded and said sill or hob mould is secured in place on said rods by suitable clips frictionally attached to said rods above and below the appropriate surfaces of said sill or hob mould. 
         [0072]    With reference to  FIGS. 29   a ,  29   b ,  29   c  and  29   d , said sill or hob mould is supported upon a chair formed from a suitable length of folded metal section  134 . The cross-sectional shape of said folded metal section is selected to provide torsional, transverse and longitudinal stiffness. In the preferred embodiment, said folded metal section is cut to length by shearing between two dies shaped to match its said cross-sectional shape. According to the attachment requirements of said folded metal section, it is optionally cut straight across or, where appropriate, said dies are shaped to provide a plurality of attachment tabs  135  formed on one or both ends. Said attachment tabs are employed, as appropriate, to fix the lower end of said chair to a base plate or its upper end to said sill or hob mould. In the preferred embodiment, suitably positioned slots are punched in said base plate or said sill or hob mould base using a portable hydraulically-operated punch. As depicted in  FIGS. 30 to 32 , said attachment tabs are passed up through said slots and are bent over flat to secure said folded metal section into place. In an alternative embodiment (not shown), said attachment tabs are twisted through approximately 90° to effect the attachment of said folded metal section. In another alternative embodiment (not shown), said attachment tabs are passed through suitable apertures and secured by welding. The embodiment of said folded metal section depicted at  FIG. 29   b  is preferred as it provides the necessary positional stability with the use of only three said attachment tabs. 
         [0073]    With reference to  FIG. 30 , a chair comprises folded metal section  134  and side panels  31 . The lower end of said folded metal section is fixed to base plate  137  by a plurality of attachment tabs  135  passed through suitable slots and folded flat. Said base plate is suitably joggled to accommodate said attachment tabs and is fixed to formwork  3  by means of suitable fasteners (positions indicated as  136 ). The upper ends of said chair side panels are turned through 90° to create transverse fixing flanges  31 . Sill or hob mould  4  is fixed to said chair by suitable fastenings (positions indicated as  39 ) passing through lower transverse flanges  8  of said sill or hob mould and transverse fixing flanges  31 . Vertical slots (not shown) are provided alternatively in side panels  34  or the sides of said folded metal section with suitable apertures in the other. Suitable fastenings (positions indicated as  138 ) passing through said side panels and said sides of said folded metal sections permit sliding height adjustment of said sill or hob mould when loosened. Obviously, in an alternative embodiment (not shown), said folded metal section may be cut to the requisite length and its upper end fixed directly to said sill or hob mould. Where this embodiment is employed, transverse strips of material are provided across the lower surface of said sill or hob mould to permit said fixing of said folded metal section. In another alternative embodiment (not shown), a similar sectional shape moulded from a suitable polymer material replaces said folded metal section and its ends are fixed to said sill or hob mould or said base plate by its said attachment tabs being passed through suitable slots and fused with a suitable hot implement. Obviously, said folded metal section may take a large variety of other cross-sectional shapes. 
         [0074]    With reference to  FIG. 32 , attachment tabs  135  on an end of folded metal section (position indicated in broken line as  134 ) are folded over flat to fix said folded metal section to sill or hob mould or baseplate  139 . 
         [0075]    With reference to  FIG. 31 , in an alternative embodiment, said attachment tabs are made in closely-spaced pairs  141 ,  142  and said folded metal section is fixed to sill or hob mould or baseplate  139  by passing said attachment tabs through a common slot  140  and then bending them flat in opposed senses. 
         [0076]    Chairs formed from a closed cross-sectional shape, for example, round, square, oval or triangular, all with plain, perforated or ribbed sides, are optionally employed where a void in a concrete slab may be tolerated. 
         [0077]    In an alternative embodiment (not shown), a sealing compound is applied to the inner surfaces of said sill or hob mould, said sealing compound dispersing into the concrete with which said mould is filled. Said sealing compound preferably takes the form of one such as Xypex®, distributed by Xypex Australia, of  45  Union Road, North Albury, NSW 2641, Australia, in which reactive chemicals diffuse into concrete using water as a migrating medium and crystallize to form a non-soluble filling of pores and capillary tracts in the cured concrete. Said sealing compound is applied in dry form with a suitable binder to the inner surfaces of said sill or hob mould and is activated by the filling of said mould with concrete. 
         [0078]    In another alternative embodiment (not shown), said sill or hob mould, immediately following pouring of a building concrete slab, is filled with concrete containing a waterproofing compound. 
         [0079]    In another alternative embodiment (not shown), said sill or hob mould side panels are provided with vertical or horizontal fluting, ribbing or doubling or are otherwise treated to provide increased stiffness. 
         [0080]    In another alternative embodiment (not shown), the upper and lower edges of said sill or hob mould side panels are rolled, ribbed or folded to provide increased stiffness. 
         [0081]    In another alternative embodiment (not shown), channels or other sections are fixed to the upper and lower inner surfaces of said sill or hob mould side panels to provide increased stiffness. 
         [0082]    In another alternative embodiment (not shown), transverse stiffeners of the type depicted as  27  in  FIG. 6  are welded to the outer or inner surfaces of transverse upper and lower flanges (depicted as  8  and  9  in  FIG. 7 ). Where said sill or hob mould is made from a light metal alloy material, said transverse stiffeners are optionally fixed by cold pressure welding. Where said sill or hob mould is made from a steel alloy material, said transverse stiffeners are fixed by spot welding. 
         [0083]    In another alternative arrangement (not shown), the side panels of said chair are effectively made telescopic as depicted in  FIG. 7  and the abutting surfaces of said side panels have formed on them complementary, ratchet-type projections which permit telescopic extension but prevent telescopic collapse. In use, said sill or hob mould is temporarily supported from said formwork at the correct height and said chair side panels are then telescopically extended and fixed to said mould to provide sustained support. Should there be a requirement to telescopically collapse said chair side panels, they are removed and physically separated for this purpose. 
         [0084]    In another alternative embodiment (not shown), the height of said sill or hob mould on said chair is adjusted by positioning pairs of opposed wedges between them. Slots are provided through said wedges to accommodate a draw bolt which is employed to draw said wedges together or increase their spacing, as appropriate. 
         [0085]    In another alternative embodiment (not shown), to minimize the possibility of conflict with reinforcing bar, plate or mesh installed in said formwork, the transverse bottom part of said chair (depicted as  13  in  FIG. 1 ) is deleted and the lower edges of said chair side panels are provided with tabs, flanges of other means for attachment to said formwork. 
         [0086]    In another alternative embodiment (not shown), a clearly visible gauge make is provided on the side panels of said chair or said sill or hob mould up to which concrete is filled in the pouring of a building concrete slab. 
         [0087]    In another alternative embodiment (not shown), said sill or hob mould is made in a regularly curved planform to meet the needs of a particular architectural situation. In this embodiment, said sill or hob mould construction is of the type described in relation to  FIG. 7 , said side panels first being separately curved to the correct radius and then joined by transverse or zigzag-type spacers which are preferably spot welded into place. Said chairs are positioned as required to support said curved mould. In another alternative embodiment (not shown), said sill or hob mould is made in an irregularly shaped planform to suit a particular architectural situation, the method of manufacturing said sill or hob mould being generally as described for that with a regularly curved planform. 
         [0088]    In another alternative embodiment (not shown), a plurality of free standing said chairs are distributed over said formwork prior to pouring of a building concrete slab and are employed as level gauges during said pouring. 
         [0089]    In another alternative embodiment (not shown), said chairs and said sill or hob moulds are made in ranges of heights and widths to suit a variety of architectural applications. 
         [0090]    In the present invention, except where clearly impractical, any feature described in one embodiment should be taken as able to be used in combination with any feature of another embodiment. 
         [0091]    Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described above. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. In case of conflict, the present specification, including definitions, will control. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect.