Patent Publication Number: US-10309110-B2

Title: Clip

Description:
TECHNICAL FIELD 
     This invention relates to a method of constructing a preform panel for receiving a settable material and more particularly to a clip for constructing the preform panel. 
     BACKGROUND 
     Concrete panels or slabs are used in a myriad of applications commercially, industrially and residentially: from the construction of a deck or a patio to the foundation of buildings and other forms of industrial infrastructure. 
     There are two main methods to assemble a reinforced concrete panel. First, for smaller or bespoke jobs, the panel is fully constructed in situ. Here the placement of side-forms and reinforcement mesh is laid out on site, and concrete is poured to cure or set in place. While this method produces custom-made panels, there are no standard panel kits currently available, thus the individual construction of panels is time-consuming, requires skill and expertise to do properly, and can entail high costs including but not limited to on-site labour, supervision and quality control. 
     The second, alternative method is a ‘precast’ method. This involves the full assembly of the formwork, and the pouring, setting and curing of the concrete in a remote location e.g. factory or builders yard. The completed panels are then transported to the site for use ready to be oriented and installed in the predetermined configuration. This method gives high quality control over the panel in the factory, and overall labour expenses are reduced. However, transport of the precast concrete panels is expensive and cumbersome due to their weight and bulk. There is additional cost and manpower required to further move the panels around a site and there is the inherent risk of damage to the panels during both transportation and installation on the site. 
     Unless defined otherwise, 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 any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of the exemplary methods and materials are described herein. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided a clip for use in the construction of a reinforced concrete panel, the panel being reinforced by a mesh comprising a plurality of parallel line wires and a plurality of parallel cross-wires connected to the line wires, the clip comprising: a base configured to engage a side wall that, in use, defines a formwork of the panel; and a body extending from the base, the body being configured to retain a line wire or a cross-wire of the mesh in an operative position of the mesh. 
     The wire may be retained via a twist-lock action. 
     The wire may be retained in any one of a number of predetermined positions. 
     An advantage of the invention is to provide an overall construction system for forming reinforced concrete panels that ameliorates some of the disadvantages and limitations of the known art or at least provide the public with a useful choice. 
     The clip forms a connection between the reinforcement mesh and the side walls of the formwork. As such, it provides a structural element to the overall preform panel assembly, giving the preform a stable, rigid structure well suited to receiving and retaining a concrete mix. 
     The clip is configured to resist structural forces that occur during transport and/or assembly and/or installation of the panels e.g. the twisting of the formwork, the mass of the settable material, and the longitudinal, horizontal, twisting and sheer forces. The clip is configured to resist forces in a number of different directions simultaneously. In some embodiments angled corner members can be employed to retain the side walls in parallel and resists skewing of the panels. 
     The clip may be configured to attach to two layers of reinforcement mesh simultaneously thereby resisting slipping of the layers relative to one another and relative to the side walls, keeping the preform panel more rigidly constrained. 
     The clip may be formed from a resilient material. This allows the flexible clip to be used for curves or irregular shaped panels. 
     This resilience of the clip allows for expansion and contraction of the concrete panel, once the concrete has cured. 
     In use, the clips locate and retain the reinforcement at a predetermined level within the finished panel. This is important as concrete is not impervious to water and a peripheral portion of any concrete panel will soak up moisture. When a reinforcement mesh is too close to the surface of a concrete panel, the moisture within the concrete can attack and corrode the reinforcement mesh. A brown/red discolouration is often seen on old concrete slabs where the steel reinforcement members have become exposed to water and begun to rust. Ultimately, the corrosion of the reinforcement mesh will deteriorate the structural rigidity of the finished concrete panel, and if the corrosion is left untreated, the concrete panel will fail. 
     In some embodiments, the body of the clip may include a passageway that can receive an end section of the line wire. The passageway may be include at least a part that is a continuous perimeter wall that completely houses a section of the line wire or crosswire when inserted into the passageway. The passageway may be a partially open channel. 
     The body of the clip may include a channel that extends perpendicular to the passageway. 
     The channel may be positioned in relation to the passageway so that when the line wire is inserted into the passageway, the line wire can be rotated through 90 degrees to locate the cross-wire in and be cradled by the channel. 
     The passageway of the body may be perpendicular to the base. 
     A central longitudinal axis of the passageway may be offset from a central longitudinal axis of the channel. 
     The channel of the body may be positioned laterally of the passageway so that the channel does not interfere with insertion of the wire into the passageway. The channel may be of open construction to rotatably receive and retain the cross-wire. A line that bisects the base and an axis of the channel may both lie in a plane that is perpendicular to the base. 
     The base of the clip may comprise a tapered profile for slidably engaging the side wall. The base of the clip may be coupled to a mount. The mount may be configured to engage both the base and the side wall thereby indirectly connecting the clip to the side wall. The mount may be engageable with the base of the clip. The mount may include a cradle for slidably receiving the base of the clip. 
     The base, body, passageway and channel of the clip may be integrally formed. 
     The clip may further comprise a stiffener to support a transition between the body and the base. The stiffener may comprise a pair of legs mounted to the base in a spaced apart configuration. The stiffener may comprise a flange that transitions from the base to the body. 
     The body of the clip may further comprise an ear, the ear extending perpendicularly to each of the passageway and the channel. The ear may include an aperture for receiving fixings therein. The aperture of the ear may be accessible from an exterior of the reinforced concrete panel. The ear may extend from the body perpendicularly to each of the passageway and second channel in two opposing directions. An outer surface of the ear may comprise an anti-translational feature. 
     The terms “line wire” and “cross-wire” are understood herein to include elements that are formed from any one or more wires, rods, and bars. The elements may be single wires, bars or rods. The elements may be formed from two or more wires, rods, or bars joined to each other. 
     The line wires and the cross-wires may be welded together. 
     The formwork of the panel is capable of receiving a pourable, settable material without the need for external support members. The pourable and settable material may be a plastic, a ceramic or concrete. 
     The clip further provides a safety feature, by concealing the sharp ends of the line wires and cross-wires of the reinforcement mesh. 
     The mesh may comprise a plurality of offset reinforcing layers. 
     In some embodiments, the base of the clip may support a plurality of bodies extending from the base, wherein each body is configured to receive a wire from a subsequent mesh and retain each subsequent mesh in an operative position. 
     Where large reinforced panels are required, multiple layers of reinforcement mesh may be required to sufficiently support the finished panel. Spacer blocks may be inserted between each layer of mesh to hold the first layer of mesh and each subsequent layer of mesh at a predetermined distance from one another. However, this is time consuming and cumbersome, with no guarantee that some spacer blocks will not move around or become ill positioned. A clip providing multiple bodies for receiving and retaining mesh only requires attaching to the sidewalls once, and the clip is no longer free to move around. The distance between each body and thereby each layer of mesh is not adjustable and remains fixed in the predetermined position when transporting, orienting and pouring concrete into the preform panel. 
     Furthermore, the multi-body embodiment of the clip does not require a cross-wire to lock onto. It can instead be fixed in place with a swage clip, epoxy or other means. It can also be used in applications with single rods. 
     In some embodiments, the body of the clip may be configured to receive either a line wire or a cross-wire of the mesh and to retain the wire in any one of a number of predetermined positions relative to the other of the line wire or the cross-wire of the mesh. 
     The body of the clip in this embodiment provides a passageway that can receive an end section of the wire and a plurality of secondary fixing points for receiving either of a line-wire or a cross-wire. The secondary fixing points may be channels for supporting or cradles for supporting and retaining wire therein. The secondary fixing points may be oriented perpendicularly to the passageway. 
     The plurality of secondary fixing points may provide an adjustment mechanism for the mesh, within the preform panel. Specifically, the cross-wire of the mesh may be placed into different cradles along the body of the clip to allow different distances between the mesh and the sidewalls. As such the clip facilitates amendments to the dimensional tolerance of the preform panel. 
     In accordance with the present invention there is provided a method of constructing a concrete reinforced preform panel, the panel being reinforced by a mesh comprising a plurality of parallel line wires and a plurality of parallel cross-wires connected to the line wires, the method comprising the steps of: (i) engaging a plurality of clips with the plurality of parallel line wires and the plurality of parallel cross-wires of the mesh; (ii) orienting a plurality of side walls to define a perimeter around the mesh, such that each side wall partially engages a base of at least one clip; and (iii) rotating each clip to retain the wire via a twist-lock action in an operative position of the mesh. 
     Engaging the plurality of clips with the plurality of line wires and cross-wires of the mesh may engage a passageway of the clip to a first wire of the mesh, such that rotating the clip urges a channel of the clip into engagement with a second wire of the mesh. 
     The first and second wires may be oriented perpendicularly to one another. 
     The method may further comprise the additional step of securing a free end of each side wall to a subsequent side wall, to define a closed perimeter around the mesh. 
     The method may further comprise the step of introducing concrete into the preform panel. 
     The method may further include the step of attaching a base to the side walls enclosing the mesh within the preform panel. 
     According to the invention there is also provided a concrete panel comprising a side wall that defines an outer perimeter of the panel, concrete within the perimeter defining opposite top and bottom surfaces of the panel, a mesh comprising a plurality of parallel line wires and a plurality of parallel cross-wires connected to the line wires embedded in the concrete, and the above-described clip interconnecting the side wall and the mesh. 
     The finished panel can be used for ground-based concrete slabs, such as pathways, outdoor amenity bases and large building slabs. However, the robust reinforcement panel can also be used for walls, where the panels are formed and then tilted into position as curtain walls (also referred to as Tilt-up panels). 
     In some embodiments, the method further comprises the step of incorporating a base under the panel. These reinforced panels can be used for suspended concrete panel applications, such as elevated walkways, bridges and suspended floors. 
     The base may connect to the side walls, to form a pan. The reinforcement mesh may also be connected to the pan. 
     The above methods allow for fast and easy assembly of a reinforced preform panel. This in turn enables cost reductions through lower labour expenses and time savings in use. Furthermore, the simplicity of the method lends itself to use by less skilled personnel, reducing the need for training and expertise. This can also reduce the personnel required to construct reinforced concrete panels on-site. 
     This method is dimensionally accurate, producing consistent and robust reinforced panel slabs. The finished panel provides a consistent high quality, strong and long-lasting product. 
     In some embodiments, the panel may be located in the predetermined position just prior to pouring the concrete. This reduces the potential for damage of the panel from weather and transportation conditions. This reduces the number of panels that are damaged or scrapped on site, as well as reducing the opportunity for transportation damage of the panels, thereby reducing material wastage. 
     The method further provides reduced shipping costs as the necessary components to create the preform panels can be flat-packed for transportation. 
     Various features, aspects, and advantages of the invention will become more apparent from the following description of embodiments of the invention, along with the accompanying drawings in which like numerals represent like components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described in further detail below, wherein like reference numerals indicate similar parts throughout the several views. Embodiments are illustrated by way of example, and not by way of limitation, with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a preform panel according to one embodiment of the invention; The preform panel, and an exploded drawing, showing mesh, clips and formwork; 
         FIG. 1A  is an exploded perspective view of the preform panel according to  FIG. 1 ; 
         FIG. 2  is a perspective view of an embodiment of a clip according to the invention; 
         FIG. 3  is a perspective view of an alternative embodiment of a clip according the invention, illustrating plugs for easy fixing of external objects to the finished panel; 
         FIG. 4  is a perspective view of an alternative embodiment of a clip according the invention, illustrating a slim-line leg design and reduced length base; 
         FIG. 4A  is a side view of the clip of  FIG. 4 , illustrating an internal bore of the clip; 
         FIG. 4B  is a perspective view of the clip of  FIG. 4 , illustrating mount engagement tabs; 
         FIG. 4C  is a top view of the clip of  FIG. 4 , illustrating a chamfered base profile; 
         FIG. 5  is a perspective view of the clip aligned for use with a single mount to form a two-piece clip arrangement; and 
         FIG. 6  is an exploded perspective view of the clip aligned for use with two symmetrical mounts to form a three-piece clip arrangement; 
         FIG. 6A  is a side view of the clip of  FIG. 4  engaged with an extension mount; 
         FIG. 6B  is a side view of the clip of  FIG. 5 , engaged with an offset mount for engaging a deep-rebated side wall; 
         FIG. 6C  is a side view of the clip of  FIG. 5 , engaged with an offset mount for engaging a narrow-rebated side wall; 
         FIG. 6D  is a side view of the clip of  FIG. 5 , engaged with a pair of offset mounts for engaging a side wall with greater depth that the clip; 
         FIG. 6E  is a side view of a two-sided joint where a clip of  FIG. 5  and a clip of  FIG. 4  are engaged with opposing side walls, the side walls both having a central swage, illustrating how the clips can be configured to straddle the swage; 
         FIG. 7  is a perspective view of a lightweight formwork mounted to a push-on clip configuration; 
         FIG. 8  is a perspective view of a double-bar clip embodiment, for use in preform panels to construct thick slabs having two sheets of reinforcement mesh; 
         FIG. 9  is a side view of the double-bar clip of  FIG. 6 , illustrating an engagement method between the clip and a side wall; 
         FIG. 9 a    is an enlarged view of encircled area B of  FIG. 9 , illustrating a notch in an upper lip channel attached to a contoured inner face of the side wall such that the upper lip can be removed to expose a smooth concrete finish; 
         FIG. 9 b    is an enlarged view of encircled area C of  FIG. 9 , illustrating a series of retaining barbs on the contoured inner face of the sidewall for retaining the clip; 
         FIG. 10  is an exploded perspective view of a preform panel comprising double-bar clips according to those of  FIG. 7 ; 
         FIG. 10A  is a side view of a double mesh arrangement using the clips of  FIG. 4 , for supporting multiple layers of reinforcement within a perimeter formwork; 
         FIG. 11  is a perspective view of a preform panel, illustrating an internal support frame therein, providing a window detail to the slab using window clips; 
         FIG. 11A  is a sectional view of an arrangement for supporting a double layer of reinforcement mesh, using clips according to the clip of  FIGS. 5 and 6 ; 
         FIG. 12  is a perspective view of the window clip of  FIG. 9 , illustrating a staggered base; 
         FIG. 12A  is a side view of the clip of  FIG. 4  in two different lengths so as to provide engagement with a rebated side wall; 
         FIG. 13  is a perspective view of a single-mesh bar chair, which provides a level for concrete finishing and for stacking and packaging of a finished slab; 
         FIG. 14  is a perspective view of double-mesh bar chair, to support double layers of mesh at a constant height and provide a level for concrete finishing and for stacking and packaging of a finished slab; 
         FIG. 15  is a side view of a clip receiving reinforcement bars, to keep a rigid edge for thick slabs and reduce the thickness of the side wall material; 
         FIG. 15 a    is an enlarged view of the circle B of  FIG. 15 , illustrating a snap-on feature of the side wall and clip; 
         FIG. 15 b    is an enlarged view of the circle C of  FIG. 15 , illustrating an acute lower lip of the side wall; 
         FIG. 16  is a perspective view of the reinforced clip of  FIG. 15  engaged with a reduced thickness side wall; 
         FIG. 17  is a schematic view of the forces resisted in the preform panel by the clips; 
         FIG. 18  is a perspective sketch of a bar-junction clip, to connect and stiffen non-welded reinforcement bars; 
         FIG. 19  is a photograph of a fully constructed concrete formwork, ready to receive a pourable substrate; 
         FIG. 20  is a perspective view of a connector for retaining a pair of preform panels in engagement with one another; 
         FIG. 21  is a side view of the connector of  FIG. 20  connecting two preform panels; and 
         FIG. 22  illustrates a top view of a series of preform panels configured and arranged to define a curved concrete reinforced profile. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments, although not the only possible embodiments, of the invention are shown. The invention may be embodied in many different forms and should not be construed as being limited to the embodiments described below. 
     While the invention is described herein in relation to forming steel reinforced concrete panels, it is understood that a reinforcement member for the panel can be formed from various metals other than steel and numerous other materials instead of metal. It is further understood, that although concrete is a commercially viable pourable substrate from which to form a reinforced panel, other pourable materials such as plastics, resins and ceramics can also be used in keeping with the invention. 
     The invention provides a clip  1  for use in the construction of a reinforced concrete panel  100 , the panel  100  being reinforced by a mesh  70  comprising a plurality of parallel line wires  72  and a plurality of parallel cross-wires  74  connected to the line wires  72 . As illustrated in  FIGS. 1 and 1A . 
     The clip  1  comprises a base  10  configured to engage a side wall  80  that, in use, defines a formwork  90  of the panel  100  and a body  20  extending from the base  10 , the body  20  being configured to receive a line wire  72  or a cross-wire  74  of the mesh  70  and to retain the wire  72 / 74  in an operative position of the mesh  70 . 
     In a first aspect of the invention, illustrated in  FIGS. 1 to 4 , the body  20  of the clip  1  is configured to receive the line wire  72  or a cross-wire  74  of the mesh  70  and to retain the wire  72 / 74  via a twist-lock action in an operative position of the mesh  70 . 
     With reference to  FIGS. 2 to 4 , the clip  1  has a rectangular base  10 . Opposing ends  15  of the base  10  are tapered to facilitate engagement with the side wall  80 . With reference to  FIG. 1 , in its simplest form, the side wall  80  is an elongate, rectangular panel. The top and bottom longitudinal edges of the side wall  80  are bent to form a planar web  81  extending between a first lip  82  and a second lip  83 . The first and second lips  82 ,  83  are bent, to each from an acute angle with the sidewall  80  that is less than 90 degrees. The lips  82 ,  83  therefore, provide a V-shaped profile at opposing ends of the side wall  80 , within which the tapered ends  15  of the clip  1  can be engaged. The tapered ends  15  of the base  10  can be slid into engagement with the lips  82 ,  83  of the side wall  80  from an end of the side wall  80 , or they can be rotated into contact with the lips  82 ,  83  from any point along the length of the side wall  80 . The side wall  80  can be made from numerous materials, depending on the application of the finished panel  100 , for example: aluminium, galvanised steel, stainless steel, plastic etc. The choice of material is primarily structural. However, the choice of material will also affect the finished concrete panel  100  as the side wall  80  can effectively provide a moisture barrier around the periphery of the panel  100 . The side walls  80  can be extruded, rolled, bent, moulded or the like. In an extruded form the side wall  80  can be configured to have an expansion joint (like core fluke), or tear-off strip to create a bull nose or coving shape on the top edge of the finished concrete panel  100 . 
     The tapered ends  15  of the base  10  preferably do not extend to a point as this would form a weak point on the base  10  and leave the clips  1  prone to detachment from the side wall  80  under load. Accordingly, the tapered ends  15  are chamfered for a smooth end profile. 
     The clip  1  in side view has a triangular profile, the body  20  extending outwardly from the base  10  to an apex which is configured to receive the mesh  70 . The body  10  is of a cylindrical shape; however, other cross-sections can be used e.g. square, rectangular, ovoid, and triangular. 
     At the apex of the body  20  is a passageway illustrated as a first channel  40  in  FIG. 2 . The channel  40  is defined by an opening extending into the body  20 . The channel  40  comprises a first portion  42 , which is open and a second portion  44  which is closed. The open portion  42  exhibits a C-shaped profile in cross-section. In contrast, the closed portion  44  exhibits a circular cross-section for receiving a line wire  72  or cross-wire  74  of the mesh  70 . When a wire  72 / 74  is inserted into the closed portion  44 , the clip  1  can rotate freely about the wire  72 / 74 . 
     Disposed on the body  20  between the open portion  42  and the closed portion  44  of the first channel  40  is a cradle, illustrated as second channel  50  in  FIG. 2 . The second channel  50  is positioned laterally of the first channel  40 . In the embodiment of the clip illustrated in  FIG. 3 , the second channel  50  is positioned perpendicularly to the first channel  40 . 
     The second channel  50 , in contrast to the open section of the first channel  40 , exhibits a U-Shaped profile in cross-section. Side arms  52  of the second channel  50  extending away from the body  20  to form a cradle for receiving and retaining the wire  72 / 74 . The opening of the first channel  40  provides a free running fit for insertion of the wire  72 ,  74  into the clip  1 . In contrast the opening of the second channel  50  is an interference fit (also referred to as a press fit or friction fit) with the wire  72 ,  74  to facilitate secure engagement with the mesh  70 . This interference fit between the wires  72 / 74  and the second open channel  50  provides a twist-lock (or snap-lock) action for securely engaging the clip  1  with the mesh  70 . 
     The body  20  extends perpendicularly from the base  10 , and as such the first opening  40  receives the wire  72 ,  74  perpendicularly to the base  10 . The second channel  50  is perpendicular to both the base  10  and the first channel  40 . 
     Reinforcing mesh  70  is typically formed by welding or otherwise joining a plurality of line wires  72  and a plurality of cross-wires  74 , where the line wires  72  bisect the cross-wires  74  perpendicularly. Accordingly, the line wires  72  and the cross-wires  74  of a mesh  70  are rarely sitting on the same plane (unless the wires  72 ,  74  are sufficiently thin that the offset in their respective planes becomes negligible), they are vertically offset. 
     This vertical offset is accounted for in the location of the centreline of the clip  1 . Because of the planar offset between the line wires  72  and cross-wires  74  of the mesh  70 , the body  20  is not positioned centrally on the base  10 . This would force the clip  1  to be handed, in respect of the lay-up of the mesh  70 . The second channel  50  is centrally located in relation to the base  10  and the first channel  40  is offset by a diameter of the wire  72 . As such, clip  1  remains symmetrically oriented to the wire within the second channel  50 . A further consequence of this non-handed embodiment of the clip  1  is that the body  20  will always be offset from the centre of the base  10  by the diameter of the wire  72 ,  74 . 
     The body  20  can be solid and extend perpendicularly from the base  10  as illustrated in  FIG. 4 . In this embodiment stiffening flanges  26  are provided to support the transition section  24  of the body  20  where it connects to the base  10 . Without the flanges  26 , the clip  1  could be vulnerable to bending under certain loading conditions. This provides a slim-line clip  1  variant. The base  10  has a length of approximately 50 mm in contrast to the clip of  FIG. 5  which has a base  10  length of approximately 100 mm. 
       FIG. 4A  is a side view of the clip of  FIG. 4 , illustrating an internal bore of the clip  1  illustrated as closed channel portion  44 . This channel can have a diameter of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, depending on the gauge of reinforcing mesh  70  to be used in conjunction with the clip  1 . Where the closed channel  44  has a diameter of 8 mm, the external diameter of the body  20  is approximately 15 mm. This then provides a wall thickness of the body  20  of about 3.5 mm. The channel  44  extends into the body  20  of the clip  20  wherein the channel  44  ceases before the base  20 . The channel  44  can extend between 20 to 50 mm into the clip body  20 ; however, if the channel  44  continues towards the base  10  a loss of lateral stiffness can occur. 
     On opposing sides of the base  10 , in a longitudinal direction of the clip  1 , there are provided engagement tabs  16 , illustrated in  FIG. 4B . These tabs  16  protrude centrally from the sides of the base  10  by 1-3 mm, to enhance engagement and/or locate the clip  1  when engaged with a connector  35  (see  FIG. 6A ). The engagement tabs  16  are mounded into the form of the clip during manufacture. The engagement tabs  16  extend across the full depth of the base  10 ; however, it is contemplated that they could be configured to only partially extend the depth of the base  10  or further, that they could be shaped to cooperate with the form of the connector. 
     The tabs  16  are clearly illustrated in  FIG. 4C , a top view of the clip  1 . The opposing corners of base  10  are rounding, providing a pair of chamfered corners  18 . This is in stark contrast to the remaining corners  18   a  which are right-angled, when viewed from above. The chamfered corners  18  are curved with a radius between 20-30 mm. This shaping of the base  10  provides an anti-rotation feature, such that when clip  1  is placed adjacent the upper lip  82  and lower lip  83  of the side wall  80 , the clip  1  is easily rotated into engagement with the lips  82 ,  83  in an anti-clockwise direction, but will not rotate into engagement with the lip s  82 ,  83  in a clockwise direction. As such the clip  1  can be considered to be handed. It is contemplated that the clip  1  can be configured left or right handed (anti-clockwise locking or clockwise locking). 
     The centre of closed channel  44  is not symmetrically aligned with the base  10 , as clearly illustrated in  FIG. 4C . The centre of channel  44  aligns with a first end  16   a  of the engagement tab  16 . The tab  16  extends along the length of the base  15  by approximately 6 mm. As such the body  20  of the clip  1  is 3 mm offset from the longitudinal axis of the clip  1  (although central in a transverse axis of the clip  1 ). This non-symmetry allows the clip to be engaged with the side wall  80  in two orientations 180 degrees opposed to each other. The two orientations will vary the offset of the reinforcement  70  from the edge of the finished panel  100  by 3 mm. As such, the clip  1  can be oriented to increase the depth into which the reinforcement  70  is embedded. 
     The embodiment of the clip  1  illustrated in  FIG. 2  also provides a transition section  24  between the base  10  and the body  20 , comprising a pair of spaced apart legs  30 . The legs  30  provide a structural stiffening feature of the clip  1 . Some form of stiffener is advantageous as the clip  1  will be supported at the base  10  in the side wall  80 , whereas the loading on the clip  1  will be introduced in multiple directions to the apex of the body  20 , namely first channel  40  and second channel  50 . Accordingly, the length of the clip  1  provides an offset between the base  10  and apex, increasing rotational loading on the clip  1 . The clip  1  can be manufactured in individual pieces such that the base  10 , body  20  and channel  40 ,  50  must be assembled before use. Alternatively, the base  10 , body  20  and channels  40 ,  50  can be integrally formed. 
     When formed as separate components, there is no requirement that each component is manufactured from the same material. This provides a way of tailoring the clip  1  for bespoke applications and moving the structural strength of the clip  1  to localised areas where high load resistance is required. 
     For integrally formed embodiments of the clip  1 , plastics are ideally suited as the construction material. First, they can be tailored with reinforcements and additives for particular applications. Secondly, plastics lend themselves to high volume manufacture, whether cast, injection moulded, vacuum moulded or thermoformed. Thirdly, plastic materials are not prone to corrosion and provide the requisite degree of resilience to compensate to the breathing of the finished concrete panel (the expansion and contraction cycles that concrete is subjected to by weather and other environmental factors). 
     Excess material is removed from the transition section  24  of the body  20  resulting in an aperture  32  centrally positioned between the legs  30  of the clip  1 . This provides a weight saving for each clip  1  and more efficient material use. The leg  30  further provides a peripheral flange  31  forming an I-Shaped cross-section of each leg  30 . 
     The clip  1  can also be configured with additional functionality, particularly where connections are desired between the finished concrete panel  100  and an external object. For example, the clip  1  can be configured to provide a fixing point or a plurality of fixing points to connect to the finished panel  100 . 
     The clip  1  of  FIG. 3  illustrates a pair of ears  60  extending in opposing directions from the body  20 . The ears  60  are aligned with the base  10  and thus extend away from the body  20  in a direction perpendicular to both the first channel  40  and the second channel  50 . The pair of ears  60  extend to a length equal to that of the base  10 , such that an end face  61  of each ear  60  is accessible in the finished concrete reinforced panel  100 . The ears  60  thus provide a mounting point for attachments to the finished panel  100 . 
     The ears  60  can be formed with a central opening  64  for receiving standard fixing such as nails, screws, pins etc. The opening  64  further provides a through aperture from one side of the finished panel  100  to the other. This can be used for locating cables and wires through the slab. 
     An outer surface  62  of each ear has an anti-translational feature, illustrated in  FIG. 3 , as a series of teeth  63  that reduce the amount of movement of the clip  1  within the slab  100 . The teeth  63  also increase the frictional resistance between the concrete and the ears  60  when using them as fixing points. The teeth  63  of each ear  60  are oriented in opposition to one another to balance the loading onto the clip  1  from either side of the panel  100 . 
     Once integrated into the finished panel  100 , the attachment points/fixing points provided by ears  60  can be used to affix things to the panel  100  and can also be used to affix the panel to the ground or other nearby structure. For tilt-up panel  100  applications, a connection point can be made between the tilt-up panel  100  and the foundation (ground where the panel  100  is formed), to assist in lifting the panel  100  up to its vertical installation orientation. 
     The connection points can be used to enable easy removal of the completed concrete panels  100  for maintenance and replacement. For example, pathways where a pavement is impinged by tree roots. The connection points can be used to raise the finished panel  100  providing access to the problematic tree roots and then the panel  100  replaced or refitted. 
     The clips  1  can be mass produced to be identical. They are dimensioned to co-operate with standard gauge reinforcement mesh  70 . The mesh is manufactured to be dimensionally accurate; however, the edges where the mesh  70  is cut to size on site can lead to dimensional fluctuations. 
     When the mesh  70  is inserted into the clip  1 , the engagement point of the clip  1 , channels  40 ,  50 , rely on the cross-over point  75  between line wire  72  and cross-wire  74  on the mesh  70 . This is a dimensionally controlled point on the mesh  70 . Accordingly, even when the edges of the mesh  70  have been poorly cut, the clip  1  will engage with the cross-over point  75  reducing the opportunity for the formwork  90  and thus the finished panel  100  to be skewed or outside of dimensional tolerance. 
     To provide additional flexibility of use, the clip  1  is configured to work in conjunction with a mount, illustrated in  FIGS. 5 and 6  as a connector  35 . The connector  35  is provided with a base  12  for engagement with the side wall  80 . Supported on a stem  14  and offset from the base  12  is a support channel  37 , for sliding engagement with the clip  1 . The support channel  37  has a C-shaped cross section defining a pair of arms  38 , into which the base  10  of the clip  1  can be slid. Accordingly, the connector  35  facilitates use of the clip  1  to engage with non-standard side wall  80  profiles. 
     The pair of arms  38  slidably grip opposing sides of the base  10  of the clip  1 . The pair of arms  38  is dimensioned to provide an interference fit with the base  10 , such that the clip  1  is frictionally held in place in the support channel  37  and requires external force to push the clip  1  through the channel  37 . The translation between the clip  1  and the support channel  37  allows the base  10  of the clip  1  to effectively be extended by use of the connector  35 , as illustrated in  FIG. 5 . In  FIG. 6 , two identical connectors  35  are illustrated in alignment with the clip  1 . This configuration allows the base  10  of the clip  1  to be effectively extended in two opposing directions for use with different sizes of side wall  80 . 
       FIG. 5  illustrates the clip  1  engaged with a side wall  80  via a single connector  35 , which is located just below a midway point on the base  10 . In this configuration a first tapered end  15   a  of the base  10  of the clip  1  is tensioned in combination with the base  12  of the connector  35  to secure the clip  1  to the sidewall  80 . 
     It will be appreciated that numerous configurations of the clip  1  and a connector  35  or plurality of connectors  35  can be used to secure the clip  1  to the side wall  80 . 
       FIGS. 6A to 6C  illustrate some of the contemplated configurations of clip  1  and connectors  35 . 
       FIG. 6A  illustrates a 50 mm clip  1  that is extended by 25 mm to allow the clip  1  to sit flush against the planar web  81  of the side wall  80  and to engage the tapered end  15  with lip  82 , while the extension connector  35   a  engages the lower lip  83  of the side wall  80  to hold the clip  1  in position. Extension connector  35   a  has similar support channel  37  to that of connector  35 . Connector  35  has not stem  16 , such that the channel  37  for gripping the clip  1  is not offset from the base  12 . The base  10  of clip  1  is slid into the channel  37  such that the pair of arms  38  adjacent the body  20  of the clip  1  abut the engagement tab  16 . 
       FIG. 6B  illustrates and alternative connector  35   b  having an extended stem  14 . In this embodiment the stem is approximately 40 mm in length. The connector  35   b  has the same base  12  and channel  37  for engaging the clip  1 . As only a single connector  35   b  is engaged with the clip  1  (in contrast to the arrangement of  FIG. 6 ), the clip  1  and connector  35   b  can engage a rebated side wall  80 , having an upper web  81  and a lower web  81   b  that is 40 mm offset (rebated) from the upper web  81 . The connector can be manufactured in a number of standard sizes to dimensionally complement variations of side wall  80 .  FIG. 6C  illustrates the connector  35  of  FIG. 6  used singularly (as opposed to in pairs), and having a 20 mm stem to accommodate a 20 mm rebated side wall  80 . 
     As alternative combinations, the clip  1  having a 100 m base can be extended to engage a 150 mm side wall by engaging two connectors  35   b  to opposing ends of the base  10 . Two connectors  35   b  having 40 mm stems can also be attached to opposing ends of the slim-line clip (50 mm base) to extend the base  10  to engage a 100 mm side wall  80  (see  FIGS. 6D and 6E ). 
     A further advantage of using the connectors  35 ,  35   b  in combination with the clip  1 , is that a swage or similar form in the side wall  80  can be accommodated. Swages provide a stiffening feature to the planar web  81 , although this swage is only required to strengthen the side wall  80  until concrete or other pourable substrate is introduced. The clip  1  has a planar base  10  and as such will not attach securely to a side wall  80  having an inward extending swage or protrusion. From a strength perspective, a swage or protrusion in the side wall  80  can be configured to extend outwardly (away from the clip  1 ) however, any protruding features from the side walls  80  could create safety or storage issues. 
     The embodiments of  FIGS. 6-6E  are provided merely as examples. In reality, numerous combinations of clips and connectors can be engaged to provide a highly flexible solution to a variety of dimensionally varied applications. 
     When smaller dimensioned panels  100  are being constructed there may not be a need for bar chairs  76 ,  77 . The use of the clips  1  provide perimeter spacers that ensures the reinforcement mesh is maintained in an operative position within the formwork  90 . Ideally any steel reinforcement should be kept a minimum distance, e.g. 40 mm, away from an external surface of the concrete slab  100 , to ensure that any water permeating the panel  100  surface does not contact the reinforcement mesh  70  and initiate corrosion thereof. In this manner the reinforcement mesh  70  can be fitted with perimeter clips  1  and laid into a mould such that the clips provide a spacing means for supporting the mesh  70  at an operative position within the mould. 
     Lightweight Side Wall Clip 
     In a second aspect of the invention there is provided a clip  101  for use in the construction of a reinforced concrete panel  100 , the panel being reinforced by a mesh  170  comprising a plurality of parallel line wires  172  and a plurality of parallel cross-wires  174  connected to the line wires  172 , the clip  101  comprising: a base  110  configured to engage a side wall  180  that, in use, defines a formwork  190  of the panel  100 ; and a body  120  extending from the base  110 , the body  120  being configured to receive a line wire  172  or a cross-wire  174  of the mesh  170  and to retain the wire in an operative position of the mesh  170 . 
     The mesh  170  may comprise a plurality of offset reinforcing layers ( 170 ′). In this aspect of the invention, the clip  101  is configured to slidably engage an inner face  181  of the side wall  180 . The side wall  180  is provided with a pair of mounting rails  185  into which the clip  101  is inserted. 
     Illustrated in  FIG. 7 , the clip  101  has a body  120  with a first channel  140  at a first end  121 , for receiving a line wire  172  of a cross-wire  174  of a reinforcing mesh  70 . An opposing, second end  122  of the body  120  comprises a pair of legs  130  that engage with the mounting rails  185  of the side wall  180 . In side view the clip  101  has a Y-Shaped profile. 
     As with clip  1  described herein, the body  120  and legs  130  of the clip  101  can be integrally formed from a resilient material such as a plastic or reinforced plastic. 
     The leg  130  has an I-Shaped cross-section to provide structural stiffness and efficient material usage. Accordingly, each leg  130  effectively has a perimeter flange  131  to stiffen each leg  130  and resist bending forces applied to the clip  101  by the mesh  170  and side walls  180 . 
     Illustrated in  FIGS. 8 and 9  is a double-mesh  170  carrying embodiment of the clip  101 . This clip  101  supports two layers of mesh  170  in an operative position with the finished panel  100 . Furthermore, the clip  101  maintains a predetermined offset between each layer of mesh  170  for optimum structural support. The clip  101  includes two bodies  120  symmetrically mounted on a single pair of legs  130 . Each of the two bodies  120  comprising a first channel  140  to receive a line wire  172  or a cross-wire  174  therein. The mesh  170  in an operative position is oriented perpendicularly to the clip  101  and perpendicularly to the side wall  180 . 
     The side wall  180  for use with clip  101  is of a lightweight construction. The side wall  180  comprises two thin wall layers  180   a ,  180   b  interconnected by a plurality of internal reinforcements, illustrated in  FIG. 9  as chevrons  189 . The chevrons  189  provide stiffness to the pair of wall layers  180   a ,  180   b  without adding unnecessary mass to the side wall  180 . 
     The chevron internal reinforcements  189  provide a further advantage (see  FIGS. 9 and 21 ) wherein the chevrons  189  provide a compressible portion of the side wall  180 . Whether the side wall  180  is used alone or disposed adjacent a subsequent side wall  180  ( FIG. 21 ) the compressible nature of the wall  180  accommodates the expansion and contraction of the concrete within the finished panel  100  such that the side walls  180  are not damaged or fractured when exposed to changes in temperature and humidity. The distance between the wall layers  180   a  and  180   b  is approximately 5.5 mm thereby providing about 3 mm of movement between the side walls  180   a ,  180   b  under compressive loading. 
     The side wall  180  further comprises an upper lip  182  and a lower lip  183 . The upper lip  182  provides a curved corner shield  182   a  and a mounting rail  185  for receiving the clip  101 . The upper lip  182  can be integrally formed with the side wall  180  of formed separately in long lengths for affixing to the side wall  180 . When formed separately, the upper lip  182  lends itself to extruded or roll formed construction or moulding. 
     Upper lip  182  provides a frangible portion of the sidewall  180  that can be easily removed. The frangible portion is illustrated in  FIG. 9 a   , wherein the base of curved corner shield  182   a  has a notch  195 , so that once the concrete mix has set within the formwork  190 , the curved corner shield  182   a  can be detached and easily removed from the remainder of the side wall  180 , exposing a rounded concrete corner to the finished panel  100 . 
     The lower lip  183  provides a planar corner shield  183   a  and a mounting rail  185  for receiving the clip  101 . The lower lip  183  can be integrally formed with the side wall  180  or formed separately in long lengths for affixing to the side wall  180 . When formed separately, the lower lip  183  lends itself to extruded or roll formed construction or moulding. 
     The mounting rail  185  is of a U-shaped section, having an open end for receiving the leg  130  of the clip  101 . The mounting rail  185  further provides an internal retention feature for engaging and securing the leg  130  therein. In  FIG. 9 b    the retention feature is illustrated as a series of barbs  186 . These barbs  186  resist removal forces ie. a pulling force separating the clip  101  from the side wall  180 . However, the barbs  186  do not hamper the clip  101  from being slid along the mounting rails  185  for repositioning. Accordingly, clip  101  can be snap-on and slid into place on the side wall  180 . This allows the clip  101  to be attached at the end of each side wall  180  section or attached directly to a desired location along the length of the side wall  180 . 
     Where double layered mesh  170  is used, the mesh  170  can be further reinforced by the use of spacers, illustrated in  FIGS. 10 and 14  as a double bar chair  76 . A single bar chair  77  can also be used to support larger formworks  90 , illustrated in  FIG. 13 . 
     Both the single  77  and double bar chair  76  are configured to receive a cross-over portion  175  of the mesh  170 . Both bar chairs  76 ,  77  include a body  79  extending between a pair of bases  78 . The bases  78  are positioned to align with the outer faces of the finished panel  100 , defining the depth of the finished panel  100 . 
     Centrally of the body  79  the bar chair  77  provides a first channel  140 ′ and a second channel  150 ′ (similar to those of clip  1 ) configured to receive a line wire  172  or a cross-wire  174  of the mesh  170  and to retain the wire  172 / 174  via a twist-lock action in an operative position of the mesh  170 . The double bar chair  76  comprises a duplicate set of first and second channels  140 ′,  150 ′ for receiving a second layer of mesh  170 . Additional sets of channels can be provided on the bar chair  77  for supporting additional layers of mesh  170 . 
     To allow the bar chair  76 ,  77  to twist-lock, the cross-over portion  175  of the mesh  170  is only supported on three of its four sides. 
     When two layers of mesh  170  are used, a bottom mesh  170  is assembled to the formwork  190  first, clipping into the side wall  180 , followed by a second mesh  170  layer. 
       FIG. 10A  illustrates an alternative embodiment of the invention, comprising two layers of reinforcing mesh  170 ,  170 ′ to be supported within the formwork  190 . The side wall  80  provides a pair of upper lips  82 ,  82 ′ and a pair of lower lips  83 ,  83 ′. All of the retaining lips for engaging the bases  20  of the pair of clips  1 ,  1 ′ are inset from the corner shields  82   a ,  83   a  of the side wall  80 . The lips  82 ,  83  are positioned to place the reinforcing mesh  170 ,  170 ′ sufficiently within the side wall  80 , such that when concrete is poured into the formwork  190 , a predetermined thickness of concrete sets around the mesh  170 ,  170 ′. This helps to avoid exposure of the mesh to water. When the finished panel  100  is exposed to water some of the water will permeate the outer surface of the finished panel  100 , this permeation will make the mesh  170  vulnerable to corrosion (rusting) if there is not a sufficient depth on concrete around the mesh  170 . The required depth of concrete around the mesh  170  will be subject to different standards depending on country, region and purpose for which the finished panel  100  is to be used. More than two layers of mesh  170  can be engaged with the side walls of the formwork  190  in alternative embodiments of the invention. 
     The corner shields  82   a ,  83   a  are angled inwards, such that when a pourable or curable substrate is introduced into the formwork  90  the shields  82   a ,  83   a  become encased within the cured substrate eg. concrete or cement. This neatly hides the shields  82   a ,  83   a  for an improved aesthetic of the finished panel  100  and further reduces protrusions on the finished panel  100  that could snag or foul nearby people or objects. 
     Vertical Panel Construction Clips 
     Concrete panels  100  to be used for vertical walls can be referred to as “tilt-up panels”. In these embodiments, an aperture is often required in the finished panel  100  for windows, doors and other domestic features ie. ducts and the like. Although any required apertures can be cut from the finished panel  100  this is wasteful of the concrete material and also requires additional work time and labour to execute the cutting process. It is also difficult to cut small holes accurately in concrete without specialised cutting equipment. Accordingly, it is useful to be able to mark-out voids within the formwork  90  prior to pouring of the concrete. 
     Illustrated in  FIG. 11  is a formwork  90 , having an internal wall form  92  defining an aperture within the formwork  90 . The remainder of the formwork  90  is constructed using a plurality of clips  1 , reinforcing mesh  70  and four side walls  80  as described herein. 
     To support the reinforcement mesh  70 , around the internal wall form  92 , there is provided a staggered clip  2 , illustrated in  FIGS. 11 and 12 . This staggered clip  2  can be used in place of the arrangement illustrated in  FIG. 5  which uses the clip  1  in combination with the connector  35 . 
     The staggered clip  2  comprises two symmetrical portions  2   a ,  2   b , arranged in series. Each portion  2   a ,  2   b  comprises a base  10 ′ and a body  20 ′ the body having a first channel  40 ′. The first channel  40 ′ of each of the two portions  2   a ,  2   b  are coaxially aligned with a line wire  72  or a cross-wire  74  such that the wire  72 ,  74  is received into the first channel  40 ′ of each of the two portions  2   a ,  2   b . In this manner, the two portions  2   a ,  2   b  are rotatably affixed to the wire  72 ,  74 . 
     Once attached to the wire  72 ,  74  the base  10 ′ of the first portion  2   a  and the second portion  2   b  can be rotated independently, in a twist-lock action, to engage the internal wall form  92  and thereby brace the internal wall form  92  within the formwork  90 . The bases  10 ′ of the staggered clip  2  can be configured to cooperate with different standard forms of internal wall form  92 , as desired. 
     Staggered clip  2  is made from a resilient material such as a reinforced plastic or alternative polymer material. 
     In place of the staggered clip  2 , described above, the clip  1  can be manufactured with different body lengths. Illustrated in  FIG. 11A , a pair of clips  1 ,  1 ′ are illustrated within a finished panel  100 , the clip  1  having a longer body  20  than the body  20 ′ of clip  1 ′. The difference in body length between the clip  1  and clip  1 ′ is equivalent to a horizontal offset (or rebate) between a lower portion  92   a  and an upper portion  92   b  of internal wall form  92 .  FIG. 11A  also illustrates a bracing block  4 , positioned between two subsequent layers of mesh  70 , to maintain a fixed relationship between the subsequent layers of mesh  70  and  70 ′. The bracing block  4  stops the mesh  70 ,  70 ′ from moving out of line or laterally between the line wire  72  and cross-wires  74 . 
     The bracing block  4  can further comprise a foot  5  that extends below the mesh  70 . The foot  5  is dimensioned to extend to the outer face of the finished panel  100  and thereby provide additional support to the formwork  90 . The foot  5  terminates in a point or apex  6 . The apex  6  is sufficient to support weight upon but is also suitably small in cross-sectional area to not be visible in the finished panel  100 . This arrangement of different length clips  1 ,  1 ′ around the internal wall form  92  is especially useful when the internal wall form  92  is extruded aluminium or plastic, etc. 
     As an alternative to clip  2 , a pair of clips  1 ,  1 ″ can be used where the clips  1 ,  1 ″ are manufactured in differing body lengths, see  FIG. 12A . In this embodiments clip  1 ″ is approximately 20 mm longer in the body  20  to accommodate a rebated side wall  80 . Similar to side wall  80  as illustrated in  FIG. 10A , having a pair of upper lips  82 ,  82 ′ and a pair of lower lips  83 ,  83 ′, these attachments being located on two surfaces  81  and  81   b , where surface  81   b  is rebated by 20 mm from surface  81 . 
     Adjustable Clip 
     In a third aspect of the invention there is provided a clip  201  for use in the construction of a reinforced concrete panel  100 , the panel  100  being reinforced by a mesh  270  comprising a plurality of parallel line wires  272  and a plurality of parallel cross-wires  274  connected to the line wires  272 , the clip  201  comprising: a base  210  configured to engage a side wall  280  that, in use, defines a formwork  90 ; and a body  220  extending from the base  210 , the body  220  being configured to receive a line wire  272  or a cross-wire  274  in any one of a number of predetermined positions in an operative position of the mesh  270 . 
       FIGS. 15 and 16  illustrate a further embodiment of the clip  201  where the base  210  is configured to include slots  217  for cooperating with flanges  284  on the inner face  281  of the side wall  280 . 
     The clip  201  comprises a base  210  and a body  220  extending therefrom. The base  220 , in  FIG. 15 , is illustrated to include three slots  217 . A single slot  217  can be used; however a plurality of slots  217  provides additional structural stability to the formwork  290 . To provide additional structural stiffness to the clip  201 , the cross-section of the base  210  is I-Shaped, providing a peripheral flange  231  to the base  210 . 
     The side wall  280  is configured to provide a number of swages of flanges  284  on an inner surface  281   a  to engage with the base  210  of the clip  201 . Accordingly, the clip  201  can be pushed-on, snapped-on or crimped-on to the side wall  280 . Once in position the clip  201  can slide along the length of the side wall  280  using the flanges  284  as a form of guide rail along the side wall  280 . 
     The flanges  284  are illustrated in  FIG. 15 a    to have a rounded end  284   a  thereby providing the flange  284  with a retention feature to snap-on to clip  201 . Similarly to clip  101 , clip  201  can be slid into engagement with the side wall  280  at an end thereof or at a predetermined position along the length of the side wall  280  ie. end access to the side wall  280  is not required. 
     The body  220  of clip  201  provides a first channel  240  for receiving a line wire  272  or a cross-wire  274  of the mesh  270 . The first channel  240  comprises a closed portion  244  and an open portion  242 , such that the open portion  242  receives the wire  272 ,  274  and the closed portion  244  retains the wire  272 ,  274 . 
     The base  210  of the clip  201  is initially engaged with the side wall  280 , after which time the mesh  270  is placed onto the clip  201  which receives the line wire  272  in the first channel  240 . Once the line wire  272  is received, the cross-wire  274  running perpendicularly to the wire  272  in the first channel  240  is received and retained by a second channel  250 . As illustrated in  FIG. 16 , a plurality of second channels  250  can be provided, arranged in side-by-side configuration along the body  220 , to retain the mesh  270  in any one of a plurality of predetermined positions relative to the side wall  280 . In this manner clip  201  provides an adjustment mechanism for the formwork  290  depending on which of the plurality of second channels  250  is selected to receive and retain the cross-wire  274 . 
     The second channel  250  is oriented perpendicularly to the first channel  240  and has a U-shaped cross-section. The diameter of the second channel  250  provides an interference fit for the wire  272 ,  274  to assist in retaining the mesh  270  in the operative position prior to the pouring of concrete into the formwork  290 . In contrast, the first channel  240  provides a free-running fit to facilitate connection of the mesh  270  to the clip  201  and assembly of the formwork  290 . 
     The side wall  280  is formed from a single panel and is easily produced in a variety of materials such as metals or plastic either through moulding, bending or extruding.  FIG. 15 b    illustrates the acute angle of the lips  282 ,  283 . In this embodiment, the side wall  280  is intended for use in constructing heavy duty panels and accordingly, the side wall  280  is constructed from a suitable gauge and strength of steel to support the loading of the desired panel  100 . 
     The geometrical form of side wall  280  is simple to allow for extrusion or bending manufacture of the panel  280 . The simplicity of the form also facilitates the use of stronger steels that would not easily or cost effectively be formed into more complex shapes. 
     In  FIG. 16  a perspective view of the side wall  280  and clip  201  are illustrated. The upper and lower lips  282 ,  283  can be seen to provide a number of apertures  282   b ,  283   b  along their length. These apertures  282   b ,  283   b  allow the pourable concrete to flow through the lips  282 ,  283  improving the connection between the concrete mixture and the side wall  280 . 
     The forces exerted onto the clips  1  and mesh  70  are shown in  FIG. 17 , the arrows illustrating the direction of the forces as applied to the formwork  90 . The clip  1  once locked in place is subject to any number of these compressive, tensile and rotational forces as the formwork  90  is transported and installed. 
     The line wires  72  and cross-wires  74  or the reinforcement mesh  70  are often welded together when the mesh  70  is manufactured. However, this typically applies to standard mesh sizes. Where the mesh  70  has not been welded at the cross-over points  75 , or where a non-standard size mesh is to be used that is not welded, a cross-over clip  73  can be used to secure the line wires  72  and cross-wires  74  and stop them moving relative to one another. A cross-over clip  73  is illustrated in  FIG. 18 . These cross-over clips  73  can be dimensioned to connect/join perpendicular wires, rods or steel bars together and assist in resisting twisting forces within the mesh  70 . 
     The cross-over clip  73  comprises a first channel  40 ″ and a second channel  50 ″ arranged perpendicularly to one another. The diameter of the first channel  40 ″ and the second channel  50 ″ is configured to provide an interference fit to the mesh  70  being used, such that the cross-over clip  73  can be pushed-on or snap-fitted to the cross-over points  75  on the mesh  70 . 
     The cross-over clip  73  can be pressed or stamped from a resilient material like metal. Alternatively the cross-over clip  73  can be moulded from plastic in large volumes. It is not necessary to use a cross-over clip  73  at every cross-over point  75  in the mesh  70 , however, the more cross-over clips  73  the stiffer the formwork  90 . 
     The invention further provides a method of constructing a reinforced panel, the panel being reinforced by a mesh  70  comprising a plurality of parallel line wires  72  and a plurality of parallel cross-wires  74  connected to the line wires  72 , the method comprising the steps of: (i) engaging a plurality of clips  1  with the plurality of parallel line wires  72  and the plurality of parallel cross-wires  74  of the mesh  70 ; (ii) orienting a plurality of side walls  80  to define a formwork around the mesh  70 , such that each side wall  80  partially engages a base  10  of at least one clip  1 ; and (iii) rotating each clip  1  to retain the wire  72 / 74  via a twist-lock action in an operative position of the mesh  70 . 
     When preparing preform panels there are a number of different ways to hold the reinforcement mesh  70  and side walls  80  in proximity to receive a concrete mix eg. bars, welding, clamps, external reinforcements etc. Illustrated in  FIG. 19 , a plurality of clips  1  are used to hold a plurality of side walls  80  together and to support and retain the reinforcing mesh  70  in an operative position. 
     The reinforcing mesh  70  is purchased from standard stock and cut to a desired size. The plurality of clips  1  are then located on both the line wires  72  and cross-wires  74  around the periphery of the mesh  70 . Specifically, the line wire  72  or cross-wire  74  is inserted into the first channel  40  of each clip  1 , such that the clip  1  is free to rotate about the wire. Not every wire needs to be clipped; however, increasing the number of clips  1  will increase the stability of the formwork  90 . 
     Four side wall  80  panels are then placed around the mesh  70  such that the base  10  of at least one clip  1  is in contact with the inner face  81   a  of each side wall  80 , to create a square or rectangular formwork  90 . Other shapes of preform panels can also be constructed and the invention is not taken to be limited to preform panels having four sides. 
     The side walls  80  can be attached to one another by corner pieces  87 . An embodiment of these corner pieces  87  is illustrated in  FIG. 1A , where each corner piece  87  comprises two planar faces  87   a / 87   b  disposed at right angle to one another. Each planar face  87   a / 87   b  is inserted into an open end  81   c  of two adjacent side walls  80  to retain the side walls  80  at right angles to one another. When all four side walls  80  have been interconnected with four corner pieces  87  a relatively stable preform structure is constructed. The reinforcing mesh  70  suspended within the side walls  80  further stiffens the structure and provides resistance to skewing of the formwork  90 . 
     To lock the formwork  90  together, each clip  1  is rotated to engage the upper lip  82  and lower lip  83  with the opposing tapered ends  15  of the clip  1 . As the clip  1  is rotated the engagement between the base  10  of the clip  1  and the side wall  80  is formed. Simultaneously, rotating the clip  1  rotates the first channel  40  about the wire  72 ,  74  therein and via a twist lock action, retains the wire  72 ,  74  within the second channel  50  of each clip  1  holding the mesh  70  in the operative position. 
     Upon initial engagement with the mesh  70 , the clip can receive either of a line wire  72  or a cross-wire  74  into the first channel  40  and the rotation of the clip  1  urges the secondary channel  50  of the clip  1  into engagement with the other of the line wire  72  or the cross-wire  74  of the mesh  70 . 
     Once the formwork  90  is constructed the formwork  90  can be reoriented or relocated prior to filling the formwork  90  with concrete to form the finished concrete panel  100 . 
     In some embodiments a tray or base can be attached into an open face of the formwork  90 . The base can be connected to at least one of the reinforcement mesh  70  and the side walls  80 . The finished panel  100  having a tray can be used with beams and trusses for suspended applications. 
     In some embodiments the side walls  80  are constructed from flexible materials to allow for curved panel profiles and more complex shapes. 
     Where multiple panels  100  are to be used adjacent one another, the finished panels  100  can be installed next to one another. As an alternative the formworks  90  can be aligned and secured in a predetermined configuration, prior to pouring of the concrete mix. A dowel or joint  65  is illustrated in  FIG. 20  for joining the formworks  90  together. 
     The joint  65  comprises a constant thickness, U-shaped section. The body  66  of the joint  65  is configured to receive two contiguous side wall panels  80 . The body  66  further provides two shoulders  67  disposed on either upright of the U-shaped body  66 , to receive and not interfere with the clips  1  attached to each of the side walls  80 . 
       FIG. 21  illustrates the joint  65  in an installed orientation, connecting a pair of lightweight sidewalls  180  engaged to a pair of clips  1 . The lightweight side wall  180  has an upper lip  182  and no lower lip  183 , such that the joint  65  can be slid over the overlaid side walls  180  below the clips  1 . The shoulders  67  of joint  65  in  FIG. 21  provide a recess  68  in which to receive the tapered ends  15  of the base  10  of the clip  1 . In this manner, the joint  65  does not interfere with the twist-lock action of the clip  1 . Once the two formworks  90  are secured to one another the concrete mix can be poured into the formwork  90  to cure. 
     To minimise on-site labour, the formwork  90  can be transported fully assembled, then simply installed in the desired location and filled with concrete. The panels can be suitably restrained in transit by securing them to a pallet. The formworks  90  are light and not cumbersome to transport as they can be nested. Some form of spacer or H-section can be placed on the formwork, vertically connecting the formworks  90  together and reducing the opportunity for damage in transit. 
     Bar chairs  76 ,  77  can be attached to the mesh  70  inside the formwork  90 , supporting and separating the mesh  70  of adjacent formworks  90 , and providing a thickness guide for the finished concrete. Bar chairs  76 ,  77  can also resist lateral forces, resist weight loads such as workmen, and resist the vertical distortions that can alter the vertical accuracy of the formwork  90 . 
     For further ease of transport, the clips  1  can be rotated to lie parallel within the formwork  90 , yet remain attached to the reinforcement mesh  70 .  FIG. 22  illustrates a top view of a series of preform panels  100 . Each formwork  90  is configured to form a trapezoidal finished panel  100 , such that the finished panels  100  can be placed side-by-side to form a curved profile. Each of the panels  100  is constructed and formed as described herein using sidewalls  80 , clips  1  and a mesh  70 . However, the mesh  70  is fabricated to orient the line-wires  72  and cross-wires  74  perpendicularly to the side walls  80 . Curved and arched pathways can be constructed in this manner to navigate fixed structures of the landscape e.g. trees, hydrants, pavements or merely for landscaping and aesthetic effect. 
     The formwork  90  provides a reinforced concrete slab which is easy to assemble, removing the requirement for highly skilled labour while still providing a high-quality product. The reinforcement mesh  70  is directly connected to the side walls  80 , exploiting the internal structure of the reinforcement mesh to support the external perimeter formwork of the preform panel. The clips  1  connect the mesh  70  to the side walls  80  of the formwork  90 , keeping the mesh  70  at a constant height and maintaining a predetermined distance between the mesh  70  and the side walls  80 . The finished panel  100  can be produced and supplied in a ready-to-assemble kit form, or pre-assembled and ready to simply locate and fill with concrete. The reinforcement mesh  70  can be supplied as single bars which are more space-efficient, or as a premade mesh which is faster to assemble. 
     Hooks and connection points can be incorporated into the formwork  90 , so that when the concrete has set, tents and other lightweight buildings can be securely fastened to the finished panel  100 . The formworks  90  can be rapidly manufactured and deployed, following confirmation of the finished panel requirements for emergency relief applications eg. such as floods, earthquakes or other situations were temporary housing is required in a short time frame. 
     The formwork  90  makes the construction of concrete slabs simple and quick, requiring a low skill level to construct a high quality product. The finished panel  100  is designed for long-term durability, helping to provide a foundation on which a community can rebuild. 
     The formwork  90  provides consistent results as it has been engineered to deliver a robust, quality, durable finished panel, being produced from a simple, repeatable process. As the components of the formwork  90  are controlled and check when made, the only variable in the finished panel is the mix of concrete and surface finish of the concrete. 
     The reinforcement mesh  70  is held at a constant height across the finished panel  100  and the distance between the mesh  70  and outer surface of the finished panel  100  is constant, making the finished panel or slab more performance reliable, and less susceptible to degradation over time. 
     Once constructed the finished panel  100  can be used to provide a myriad foundations to pathways, decks, buildings, pavements, recreational areas, storage facilities, sheds, garages etc. 
     It will be appreciated by persons skilled in the art that numerous variations and modifications may be made to the above-described embodiments, without departing from the scope of the following claims. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. 
     Unless defined otherwise, 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 any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of the exemplary methods and materials are described herein. 
     It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 
     In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.