AU2008281325A1

AU2008281325A1 - A building panel and locking device therefor

Info

Publication number: AU2008281325A1
Application number: AU2008281325A
Authority: AU
Inventors: Roger Farquhar
Original assignee: Mach Systems Pty Ltd
Current assignee: Mach Systems Pty Ltd
Priority date: 2007-08-02
Filing date: 2008-07-30
Publication date: 2009-02-05
Also published as: WO2009015433A1; US20110192107A1

Description

WO 2009/015433 PCT/AU2008/001105 1 A Building Panel and Locking Device Therefor Field of the invention The present invention relates to a building panel. In particular, although not exclusively, the invention relates to a precast concrete building panel. The invention 5 also relates to a method of casting a building panel. While the building panel is commonly described herein in terms of a wall panel, the invention may have application to other types of precast panels including ceiling, roof and floor panels. The present invention also relates to a connecting system for precast cementitious components. In particular, although not exclusively, the invention relates to 10 a connecting system which is used to secure precast concrete wall panels into edgewise abutting relationship with each other. Thus, it may be used to secure two panels side by side or one panel atop another. The invention may also have application to connecting a wall panel to a slab. The invention also relates to a locking device for concrete components. 15 Background of the invention Traditionally, precast concrete panels are formed as substantially solid bodies of concrete, albeit with reinforcing material. The thicker the concrete panel, the greater its insulative properties. Thermal insulative properties are measured in terms of R value and an R value of 1.5 is desirable for building walls. However, solid concrete panels 20 would need to have a theoretical thickness of 375mm millimetres in order to exhibit an R value of 1.5 and therefore achieve satisfactory thermal insulative properties. It is known to provide locking devices that interconnect precast concrete panels or other components. See for example, my earlier Australian patent application no 71452/00. In this patent application, the locking devices comprise pins and keepers. 25 The pins are connected to one concrete component and are received in a keeper connected to another concrete component. The pin and associated keeper are disposed upon respective mating edges of the two concrete components. Thus, once the two WO 2009/015433 PCT/AU2008/001105 2 edges are brought into mating engagement, it can be difficult to align the parts of the locking device and therefore difficult to effect the locking operation. It is therefore one object of the present invention to provide a building panel or a method of casting a building panel which overcomes at least some of the 5 aforementioned disadvantages. It is an alternative object of the present invention to provide a connecting system for concrete components which may be remotely actuated. It is also an object of the present invention to provide a locking device for concrete components which addresses the abovementioned disadvantage. Yet another alternative object of the present 10 invention is to provide products which at least provide the public with a useful choice over known products. Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction nor that this prior art 15 could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art. Summary of the invention In accordance with a first aspect of the present invention there is provided a building panel being generally planar in form and having a core which is substantially 20 planar in form with opposite sides, the core being substantially aligned with the plane of the building panel, with cementitious material disposed on both sides of the core, the core being formed with a series of substantially parallel open channels which are arranged with the openings on alternate sides of the core, some of the channels being filled with the cementitious material. 25 The channels in the core may extend from top to bottom of the core and be generally aligned with the height dimension of the finished building panel. Thus the channels are arranged to alternate from one side to the other across the width of the core. The core may have a uniform cross-section over its height. Consequently, the WO 2009/015433 PCT/AU2008/001105 3 form of the core could be described as corrugated, undulating, sinusoidal or crenellated. Preferably the corrugations are of a regular formation. The term corrugated includes a zig-zag formation, preferably a regular zig-zag formation. A preferred profile is one which reduces waste. The core may be of uniform thickness so that the crests on the 5 first side of the core define the openings on the second side of the core and the openings on the first side of the core define the troughs on the second side of the core. In one form, each of the channels has a necked region at or adjacent the opening and a main void, wherein the necked region is of narrower dimension(s) than the main void. In this form, the cross-section of the channels may be described as dovetailed. 10 In the finished panel, the cementitious material will be provided on both sides of the core, extending into some or most of the channels thereby creating alternating "columns" of cementitious material on either side of the core, with columns on the same side of the core being joined by a common plane of cementitious material. In the form with dovetails, the cementitious material on each side of the core is interlocked with the 15 core by virtue of the necked regions. The building panels according to the present invention may be precast building panels. The precast building panels may be part of a building system where the building panels are shaped so as to mesh with each other and also a building slab. For example, one possible building system is described in Australian patent no 785414 in the name of 20 MACH Systems Pty Ltd. While the specification describes the invention in the context of precast building panels, the invention is not limited thereto and the present invention may also be applied to a building panel which is poured in situ. The core of the building panel may comprise insulative material. The core may also be moisture impervious to minimise the penetration of water or moisture from the 25 outside of a building to the inside. The core may be moulded or extruded to shape. In a preferred form of the invention, the core is formed of rigid cellular plastics material, for example, expanded polystyrene, expanded polypropylene or expanded polyethylene. The core may be cut from a solid block of cellular plastics material, for example by a hot wire. The core may have a smooth outer skin. Alternatively, the outer surface of the WO 2009/015433 PCT/AU2008/001105 4 core could be shaped or roughened or deformed to enhance bonding with the cementitious material. The building panel may also include reinforcing material. For example, traditional steel reinforcing mesh may be employed. However, alternative reinforcing materials 5 may be used. These include steel mesh or fabric such as expanded metal, fibreglass fabric or carbon fibres. The core may incorporate holding means for the reinforcing material. For example, the core may include integral protrusions to create a seat for the reinforcing material. Alternatively, reinforcing sheet material such as fibreglass fabric may be permanently bonded to the outermost surfaces of one or both sides of the core. 10 Within the building panel, the core may extend from edge to edge and top to bottom. However, preferably the core does not extend all the way to the top and the bottom so that the two concrete sides of the panel may be joined to create concrete 'beams' at the top and bottom of the panel. Rather than extending edge to edge, the core size may instead be a standard 15 width (and height), with the building panels being of a width to accommodate a single core or multiple cores arranged side by side. The cementitious material is preferably concrete, which is usually a composition of gravel, sand, cement and water. It is possible that different grades of cementitious material may be used on either side of the core. For example, a different density of 20 concrete may be used on one side of the panel compared to the other side. This may be to reduce the overall weight of the panel while balancing strength and thermal performance characteristics. Apart from concrete, other cementitious materials may be employed such as the newly developed cementitious materials. One such example is HySSIL developed by 25 CSIRO in Australia. This modern cementitious material does not generally employ aggregate. It is aerated by the use of chemicals to produce insulated cementitious material which is lighter in weight than traditional concrete.

WO 2009/015433 PCT/AU2008/001105 5 In a preferred form of the invention, the building panel has a higher density cementitious material e.g. 50MPa concrete on one side of the core and relatively lower density cementitious material on the other side of the core, such as HySSIL or other forms of lightweight concrete (the units MPa refer to compressive strength). This 5 arrangement improves the thermal performance of the panel when installed with the higher density cementitious material on the inside wall of a building and the relatively lower density cementitious material on the outside wall of the building. The use of the lower density material reduces the overall weight of the panel. A building so constructed constitutes a second aspect of the present invention. 10 The building panel may also employ void formers. The void formers may be in the form of inserts which fit with or into the channels in the core to preclude one or some of the channels from being filled with cementitious material. This facilitates the creation of service ducting for cabling, water pipes, air ducts for space heating or ducts for thermal heating pipes. These void formers are suitably attached to the core prior to 15 pouring of the cementitious material. The panel may also include a lifting bracket. The lifting bracket may comprise one or more lifting rods which extend into the channels to become embedded in the cementitious material. Preferably, the lifting rod(s) extends the full length of the panel. The lower ends of the lifting rods may have flanged ends. Preferably, there are three 20 lifting rods with two positioned in adjacent channels on one side of the core and the other in an intermediate channel on the other side of the core. The three rods are united at the upper end by a lifting frame. In accordance with a third aspect of the present invention, there is provided a method of casting a building panel, the method including: 25 using cementitious material of at least two different densities including a relatively higher density material and a relatively lower density material; placing a first layer of the lower density material into a mould; WO 2009/015433 PCT/AU2008/001105 6 placing a core assembly over the first layer, the core assembly being substantially planar in form; and placing a second layer of the relatively higher density material over the core assembly. 5 The mould may be vibrated and allowed to set. The core assembly may include any of the features described above in connection with the first aspect of the invention such as reinforcing material, void formers, lifting brackets, cabling, water pipes, heating conduits etc. In accordance with a fourth aspect of the invention, there is provided a method of 10 constructing a building using a plurality of building panels cast according to the method as set out above in the third aspect wherein the panels are installed with the higher density material on the inside of the building and the lower density material on the outside of the building. In accordance of the fifth aspect of the present invention there is provided a 15 connecting system for precast cementitious components including: first and second precast cementitious components adapted to be arranged in abutting relationship in an assembled configuration, the first and second precast components having respective edges which face each other in the assembled configuration; and 20 a locking mechanism including mutually engageable components disposed at the facing edges, the locking mechanism including a remote actuating means to effect locking of the mutually engageable components at or beyond a third edge of one of the first and second precast components, to secure the first and second precast components together. 25 Where the two precast components are arranged adjacent to one other then the third edge may be on top of one of the components. Where the precast components are WO 2009/015433 PCT/AU2008/001105 7 arranged one atop the other then the third edge may also be atop the upper component. This renders the remote actuating means most accessible when the components are being assembled. Typically, at least one of the components is substantially planar in form having a length, width and thickness. Side edges will be therefore defined across 5 the thickness dimension at the sides. Also, top and bottom edges will be defined across the thickness dimension at the top and bottom. More particularly, the present invention provides a connecting system including: first and second precast cementitious components adapted to be arranged irn abutting relationship, the first and second precast components having respective first 10 and second edges which face one another in the assembled configuration; a pin having a head extending from the first edge of the first component; and a locking device including a locking member which is disposed at the second edge of the second component, the locking member being moveable between an unlocked configuration and a locked configuration whereby it is adapted to receive the 15 head of the pin, the locking device further including an elongate member connected to the locking member and extending to a third edge of the second component, wherein operation of the locking member may be effected from the third edge by the elongate member. The precast cementitious components may comprise wall panels which may be 20 secured side by side to each other (in edgewise abutting relationship or alternatively may be secured one atop the other. The connecting system might also be used to join a wall panel to a slab or a concrete footing. Also, precast cementitious roof panels could be interconnected using the system. The system could also be used to join and fasten precast ccementitious floor panels together. 25 In a system where one panel is disposed atop the other, the pin may dually serve as a lifting pin to move the panels into position. Such lifting pins are supplied by Reid Construction Systems Pty Ltd of Australia. These pins are cast into the component. Additionally, a semicircular recess is formed about the pins such that they do not WO 2009/015433 PCT/AU2008/001105 8 protrude beyond the main surface of the associated edge but access to the pins can still be obtained. The first and second facing edges of the precast cementitious components may have a complimentary profile as described in my Australian patent no 785414. 5 The elongate member forming part of the locking device may be movable linearly by the actuating means to effect operation of the locking member. The elongate member may comprise a rigid member such as a rod or a bar or alternatively may comprise a flexible member such as a cable. Where the elongate member is a rod, the rod may be threaded at the upper end. By screwing a nut onto the upper end of the 10 elongate threaded rod, this will serve to draw the rod out of the concrete component once the nut abuts against the third edge. However, other means of moving the elongate member may also be employed. For example, if the elongate member is a cable, a cable actuating device may be used. The elongate member may also be a combination of a cable and a rigid member such as a rod. 15 In one particular form of the invention, there may be a plurality of locking members, each of which is connected by a short length of cable to a common elongate rod which extends to the third edge. Thus a plurality of locking members may be operated simultaneously. Where the present invention is used to connect a wall panel to a slab or footing, 20 the threaded rod may extend upwards through the height of the wall panel and be connected to a roofing component. This effectively ties the roofing component to the floor slab which may be a requirement in some cyclone areas. The locking member may comprise any suitable member which is adapted to engage with the pin. Preferably, the locking member is an arcuate member with a 25 recess formed to receive the head of the pin. For example, the locking member may be arcuate member which is forked. More particularly, the locking member may be a part cylindrical shell. For example, the locking member is preferably one-half to two-thirds of a cylinder with the missing part defining a gap to receive the head of the pin.

WO 2009/015433 PCT/AU2008/001105 9 The locking member may be pivotally mounted to the second component. An axial spigot may be incorporated into the locking member for this purpose. Preferably, the two ends of the spigot are received into a shaped plastic spacer which is cast into the concrete component. 5 Preferably, the locking member is pivotally connected to the elongate member. Most preferably, the interconnection in the unlocked configuration is at a point further from the third edge than the pivot axis to effect rotation of the locking member. In accordance with a sixth aspect of the present invention there is provided a locking device for use with a precast concrete component to lock the component to 10 another precast concrete component, the device including a locking member adapted to receive the head of a pin extending from the edge of the other component; and an elongate member connected to the locking member, the elongate member being adapted for remote operation of the locking member. The locking device may be cast into the concrete component. The locking device 15 may include any of the features described above in accordance with the fifth aspect of the present invention. As used herein, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude other additives, components, integers or steps. 20 This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be 25 incorporated herein as if individually set forth. The invention consists in the foregoing and also envisages constructions of which the following gives examples.

WO 2009/015433 PCT/AU2008/001105 10 Brief description of the drawings In order that the invention may be more fully understood, some embodiments will now be described by way of example with reference to the figures in which: Figure 1 is a horizontal cross-sectional view through a portion of a building panel 5 according to a preferred embodiment of the present invention; Figure 2 is a horizontal cross-sectional view through a portion of a building panel slightly modified from that shown in Figure 1; Figure 3 is a schematic longitudinal cross-section showing a lower detail of the building panel of Figure 2; 10 Figure 4 is a schematic longitudinal cross-section showing an upper detail of the building panel of Figure 1; Figure 5 is a horizontal cross-sectional view showing a corner junction between two building panels of the type illustrated in Figure 1 or 2; Figure 6 is a perspective view of a core assembly, further illustrating a lifting 15 bracket assembled with the core assembly; Figure 7 is a perspective view showing the lifting bracket in isolation; Figure 8 is a perspective view showing an upper frame forming part of the lifting bracket of Figure 7; Figure 9 is a schematic top view of a building panel illustrating the lifting bracket 20 in position; Figure 10 is a vertical cross-section aligned with the general plane of the building panel showing the inclusion of heating conduits; WO 2009/015433 PCT/AU2008/001105 11 Figure 11 is a vertical section through B-B of Figure 16, illustrating the airflow through the building panel; Figure 12 is an exploded perspective view of an insert assembly for a service conduit for the building panel; 5 Figure 13 is a perspective view of a heating conduit for the building panel; Figure 14 is an exploded view of a space heating conduit for the building panel; Figure 15 is a cross-sectional view through a building panel showing the arrangement of service conduits and heating conduits of Figures 12-14 assembled with the core assembly; 10 Figure 16 is a partial perspective view of a connecting system in accordance with a preferred embodiment of the present invention; Figure 17 is a partial perspective view showing the connecting system of Figure 16 with the two concrete components in assembled configuration; Figure 18 is a diagrammatic view illustrating the locking mechanism for use in the 15 connecting system shown in Figure 16 prior to interconnection; Figure 19 is a view of the components of Figure 18 just prior to engagement; Figure 20 is a perspective view of the components of Figure 18 in full engagement; Figure 21 is a sectional view through the connecting system of Figure 18; 20 Figure 22 is a front view of concrete components connected using the connecting system of Figures 16 to 21; WO 2009/015433 PCT/AU2008/001105 12 Figure 23 is a front view of a connecting system according to another preferred embodiment of the present invention; Figure 24 is a front view of a connecting system according to Figure 23, except shown in the locked configuration; 5 Figure 25 is a diagram illustrating the mating profile of the two concrete components; Figure 26 is a schematic perspective view showing the mating profile of the two concrete components; Figure 27 is a detail of the connecting system of Figure 23 shown in the unlocked 10 configuration; Figure 28 is a detail of the connecting system of Figure 23 shown in the locked configuration; Figure 29 is a detailed view of two positions of the locking member. Detailed description of the embodiments 15 Figure 1 is a horizontal cross-section through a core assembly 10 incorporated into a building panel 12. The core assembly 10 includes a core 14 which is constructed of high density expanded polystyrene. A suitable material is sold under the brand name Isolite VH. The core has a substantially uniform cross-section throughout its height. The cross-section is in the shape of a regular zig-zag of uniform thickness. The cross 20 section defines channels 16, albeit rather shallow channels which extend substantially parallel to each other in the height direction of the finished panel. The channels open towards alternating sides of the core 10. The resulting shape of the core 14 is zig-zag as shown.

WO 2009/015433 PCT/AU2008/001105 13 The zig-zag core is cut by hot wire from a solid block of polystyrene having dimensions of 5.5m long x 1220mm wide and 600mm thick. The cross-section selected is easy to cut and reduces waste. The core has dimensions of length (which may equate to height in a wall panel), 5 width (the other major dimension besides length/height) and thickness. The width of the core 14 may be substantially commensurate with the width of the building panel 12. The zig-zag core 14 defines external points 22. On both sides of the core 14, steel reinforcing mesh 24 is bonded/secured to the external points 22 to extend across the opening 17 of each of the channels 16. The reinforcing mesh 24 extends on both 10 sides of the core 14 and is substantially commensurate with the length (i.e. height) and width dimensions of the core 14. Instead of steel reinforcing mesh, fibreglass reinforcing mesh may be used. Alternatively, as shown in Figure 2, the core assembly 10 may be formed of sheets 14a, 14b of a standard width which may be joined to make up the required width 15 in the building panel 12. Figure 2 illustrates a join 30 between two polystyrene core sheets 14a and 14b having complementary edge profiles. As shown in Figures 1 and 2, the core assembly 10 is disposed essentially within the building panel so as to be substantially aligned with the general plane of the building panel 12. The core assembly 10 is inserted into a mould so that cementitious material 20 extends on both sides of the core assembly 10 and in most cases extends into the channels 16. As will be appreciated, this creates parallel spaced columns of cementitious material within the boundary defined by the channels 16. These columns are joined by the concrete which extends along the outside of the building panel. The cementitious material conforms to the shape of the dovetail channels 16. 25 The cementitious material used in the building panel 12 may be concrete. A preferred material is aerated cementitious material such as HySSIL developed by CSIRO in Australia.

WO 2009/015433 PCT/AU2008/001105 14 The current Australian government guidelines for home insulation provide that in temperate zones, the insulation value for building walls should be R-1.5 or preferably R 2. It is believed that the present invention can achieve an R value of 1.74 by adopting the following design guidelines: 5 a. Core material to be Isolite VH (expanded polystyrene) of 50mm thick, providing an R value of around 1.28. b. HySSIL cementitious material of 115mm in thickness is believed to give an R value of 0.46. R1.28 + RO.46 = R1.74 10 It is understood that further improvements in the R value could be achieved if HySSIL cementitious material of 1500kg/cm 3 was used for one side of the building panel and HySSIL cementitious material of 900kg/cm 3 was used for the other side of the building panel 12. While most of the channels 16 are intended to be filled with cementitious 15 material, one or a number of these channels 16 may remain unfilled to provide service conduits. Void formers in the form of tubular plastic inserts 34 may be used for this purpose. Figure 12 also shows an insert assembly comprised of a conduit 88 having a lower port 90 and a guide insert 92 for guiding cables or heating conduits 82. See also the discussion below in connection with Figures 12 to 15. 20 Cabling (not shown) may also be inserted into the core assembly 10, prior to being placed into the mould. The left hand panel of Figure 5 shows one embodiment where the width of the core 14 is substantially commensurate with the width of the building panel 12. On the other hand, Figures 3 and 4 illustrate the vertical extent of the core 14 relative to the 25 building panel 12. At the bottom, the core 14 does not extend to the bottom of the building panel 12 but falls short by about 80mm to provide a lower 'beam' of concrete or WO 2009/015433 PCT/AU2008/001105 15 cementitious material. At the top, the core 14 provides an upper beam height of approximately 100mm. The concrete building panels 12 of the present invention may be compatible with known precast concrete building systems. In particular, the building panels 12 of the 5 present invention may be constructed in accordance with the principles set down in Australian patent no 785414 in the name of MACH Systems Pty Ltd, the details of which are incorporated herein by reference. For example, as described in this Australian patent the building panel 12 may be mounted on a slab 40 provided with a rebate 42 to accommodate the building panel 12. The profile of the rebate 42 and the bottom edge of 10 the panel 12 may be complementary or meshing to maintain the building panel 12 relative to the slab 40. Additionally, locking means (not shown) may be provided to secure the building panel 12 to the slab 40 and the panels to each other. Details of the edge profiles and the locking mechanism are disclosed in the abovementioned Australian patent and the reader is directed to that earlier specification for further 15 information. Further, the reader is also directed to the locking device for precast concrete components, discussed further below in Figures 16 to 19. Figure 5 shows the engagement between two building panels 12 arranged at 90* to define a corner of a building. The two panels 12 may be locked together by means of any suitable locking mechanism as mentioned above. 20 Figures 6 to 9 illustrate the form of a lifting bracket which may be used to lift the building panel 12 once it has been cast. Figure 6 simply illustrates the lifting bracket 44 relative to the core assembly 10. Figure 7 illustrates the form of the lifting bracket 44 by itself. The lifting bracket 44 comprises three elongated rods 46. The rods may be threaded or the ends of the rods may be threaded. At the lower end of the rods 46, the 25 rods are coupled to nuts with winged flanges 48. At the upper end, the rods 46 are coupled to an upper lifting frame 50 which includes three triangularly spaced nuts 52 which engage with the upper ends of respective rods 46. The lifting frame 50 further includes a lifting eye 54.

WO 2009/015433 PCT/AU2008/001105 16 As can be seen most clearly in Figure 9, the three rods 46 extend into three adjacent concrete columns 17, two on one side of the building panel 12, and one on the other. The rods 46 may extend the full height of the building panel 12 or may extend partially into the building panel 12 as depicted in Figure 6. 5 The lifting bracket 44 may be preassembled as part of the core assembly 10, prior to insertion of the core assembly 10 into the casting mould. Thus, the elongate rods 46 may be attached to the reinforcing material 24 in the core assembly 10. Suitably, there would be two lifting brackets 44 employed in each building panel 12, thereby distributing the load over six columns 17 in the cast building panel 12. 10 The mould used to cast the building panel comprises a casting bed of conventional form. The building panel 12 is cast on the casting bed with its general plane being horizontally disposed on the casting bed. The outside perimeter of the building panel 12 will be defined by formwork attached to the casting bed. The casting bed 62 will thereby define one side of the finished building panel 12. 15 Once the mould 60 is ready, a first layer of HySSIL aerated cementitious material (or other lightweight concrete) is placed in the base of the mould. The HySSIL is screeded to a predetermined depth that will allow for expansion of the material due to the contained gas producing additives (assume expansion of about 30%). The core assembly 10 is positioned within the mould so as to allow a desired 20 amount of cementitious material to form on both sides of the core 14. The desired position of the core assembly is achieved through the used of Nirvana Connectors 32 (see Figure 15). These are tapered fibreglass rods manufactured by Reid Constructions Pty Ltd of Australia. The Nirvana Connectors pierce through the polystyrene core 14 and protrude beyond either side of the core 14 to act as spacers to hold the core at a 25 predetermined spacing from the casting bed. The Nirvana Connectors may also be adapted to hold the steel reinforcing in place. A layer of high density concrete (50 MPa) is then placed on top of the foam core and the casting bed is vibrated in the conventional fashion to enable the cementitious WO 2009/015433 PCT/AU2008/001105 17 material to settle in the mould. This will also enable the cementitious material to be worked into the channels 16 of the core 14, on the lower side of the core 14 within the mould 60. Those skilled in the art will be aware that the polystyrene core will have buoyancy 5 tending to urge the core 14 upwards during vibration. Pascals Principal provides: where a body is wholly or partly immersed in a fluid it is acted upon by an upthrust equal to the weight of fluid displaced. In this configuration with the high density concrete disposed above the lower density HySSIL, Pascal's Principal is exploited to maintain the core in position. 10 In this case the upthrust = 1,500 kg/cm (weight of HySSil) whereas the weight of the concrete on top of the foam core is 2,500 kg/cm. It should be noted that the depth of the layer of HySSiI concrete will be screeded to a predetermined level to allow for the expansion of the material as the chemicals produce the hydrogen bubbles, allowing for a 30% expansion rate. 15 As will be understood from Figure 1, the angular ribs of the foam core will tend to sink into the HySSil to the point where the core 14 is supported by the Nirvana connectors. The heavier density concrete will then resist the upthrust and force the expanding HySSil to progressively fill the V-shaped channels 16. 20 The side of the panel presenting the upper surface as it lies on the casting bed is then hand finished and the cementitious material is allowed to set. Once the cementitious material has set to a satisfactory level, the building panel 12 can be lifted via the lifting brackets 44 (Figures 6 to 9) to an upright or near vertical position (as per Figure 6). The formwork may be stripped from the perimeter of the 25 building panel 12. From this position, the panel 12 is moved to a rack (not shown) for curing and storing. The casting bed is then ready for casting the next building panel.

WO 2009/015433 PCT/AU2008/001105 18 Figure 10 illustrates a heating assembly 80 that may be incorporated into the building panel 12 in accordance with the present invention. The heating assembly 80 may incorporate the features described in our earlier International application no PCT/AU2006/000737 entitled Solar "Earth Module", the details of which are 5 incorporated herein by reference. The heating assembly 80 includes a conduit 82 formed from black polypropylene pipe arranged in a U-shape having upper ends, the first of which forms an inlet for the heating fluid and the second of which forms the outlet for the heating fluid. The heating fluid may be heated by any conventional means such as a gas or oil boiler or solar 10 heating. Particular reference is made to our earlier application PCT/AU2006/000737 which teaches methods and apparatus for solar heating. As shown in Figure 10, the conduit 82 extends through two adjacent channels 16 of the core 14, the two channels 16 being arranged on the same side of the core 14. The conduit 82 extends through the higher density concrete layer. The U-shaped 15 conduits 82 extend from the top of the building panel 12 down through the higher density concrete layer created in channel 16, through the concrete 'beam' at the bottom of the building panel 12 and then up the higher density concrete layer defined by adjacent channel 16. Alternatively, the two links of the conduits 82 may be arranged to extend within the same channel 16 as depicted in Figure 15. 20 In another embodiment, the conduits 82 may be arranged within a space heating conduit 88 of the type depicted in Figure 12. The heating fluid e.g. water carried by the conduit 82 may be heated by any known means such as a fossil fuel boiler or a solar collector unit. The heating fluid passes through the conduit 82 to heat the panel 12. The heat retained within the 25 building panel 12 is given off as radiated heat over a period of time. Additionally, the heat may be distributed by means of a convection current which flows through the space heating conduit 88 as depicted in Figure 11. The space heating conduit includes a lower air inlet port 90 and an upper outlet port 91. Figure 14 illustrates the form of the WO 2009/015433 PCT/AU2008/001105 19 space heating conduit 88 which is inserted into one of the channels 16 of the core, prior to casting. Figures 16 to 22 illustrate a connecting system which may be used to connect the building panels 12 together. However, the concrete component connecting system has 5 application beyond this and may be used on any suitable precast cementitious components. The connecting system 110 in Figure 16 includes a first concrete slab 112, only a portion of which is illustrated in Figure 16. Figure 16 depicts an outer periphery 114 of the slab 112. Along the upper edge of the outer periphery 114 is formed a first edge 116 10 of the slab 112. Figure 16 also illustrates a portion of a precast concrete wall component in the form of a panel 118 which defines a second edge 120. The second edge 120 is located on the lower periphery of the precast concrete panel 118. The second mating edge 120 faces the first edge 116 in the assembled configuration which is illustrated in Figure 17. These facing edges 116, 120 are substantially complimentary in profile as 15 described in my Australian patent no 785414, the details of which are incorporated herein by reference. Protruding from the first edge 116 is a pin 122 which is cast into the concrete slab 112. The pin 122 has a head 124 which is uppermost. The panel 118 incorporates a locking device which includes a locking member 126 disposed at the second edge 120 20 of the panel 118 and a threaded rod 128 which extends from the locking member 126 at the second edge 120 to a third edge 130 of the slab 118. The third edge 130 is opposite the second edge 120. The locking member 126 is received in a void former 132 comprised of plastic so that the locking member 126 may be secured relative to the concrete panel 18. The locking member 126 is shown in greater detail in Figures 18 to 25 21. Referring to Figure 18, it can be seen that the locking member 126 is in the form of a partly cylindrical shell 134 which is formed with spigots 136 which are rotatable within the plastic void former 132 (Figure 16). The threaded rod 128 is connected to the part-cylindrical shell 134 through a connecting pin 138. In the unlocked configuration WO 2009/015433 PCT/AU2008/001105 20 shown in Figure 18, the connecting pin 138 is disposed further away from the third surface 130 than the spigots 136 so that when the threaded rod 128 is pulled in the upward direction, the part-cylindrical shell 134 will be caused to rotate in a clock-wise direction around the spigots 136. 5 The part-cylindrical shell 134 is only one-half or two thirds of a full cylinder, defining a gap 140 in the cylindrical wall which can be most clearly seen in Figure 20. However, in the disposition of Figures 18 and 19, the gap 140 is disposed downwardly so that when the locking member 126 approaches the pin 122, the head of the pin 24 can be received in the gap 140. 10 It can also be seen in the Figures that the part-cylindrical shell 134 is split, with the opening of this split 142 defined at the edge of the part-cylindrical shell. This enables the two parts of the cylindrical shell on either side of the pin head 124 to engage underneath the head 124 as the shell 134 is rotated. When the connecting pin 138 reaches its uppermost position shown in Figure 20, the part-cylindrical shell 134 will 15 be fully engaged with the head of the pin 124, forming a secure connection. Reverting to Figures 16 and 17, it can be seen that a truss support bracket 144 is mounted on the third edge 130 with the threaded rod 128 extending through an aperture 146 in the bracket 144. When a nut (not shown) is attached to the threaded rod 128 and engages against the support bracket 144, continued turning of the nut will draw the 20 threaded rod 128 in a direction out of the panel 118 to rotate the locking member 126 to the engaged configuration illustrated in Figure 17. Figure 22 illustrates a front view of a precast concrete wall panel 118 mounted on a slab 112. The precast concrete wall panel 118 is cast with openings defining the windows and doors. Additionally, the panel 118 may be cast so as to simulate 25 overlapping wallboards as shown. Additionally, other joinery elements such as architraves, window sills and doorsills may be simulated in concrete by being precast into the concrete panel 118. The timber joinery such as window frames, windows, door frames and doors may be later installed.

WO 2009/015433 PCT/AU2008/001105 21 The wall panel 118 is shown with four locking members 126 which engage with respective pins 122 cast into the slab 112. While the above describes the locking of a wall panel 118 onto a slab 112, this embodiment may also have application to lock two slabs together. 5 Figures 23 to 28 illustrated another embodiment of the concrete component connecting system 110' whereby two wall panels 118' and 118" may be connected to each other. However, it could also have application to a wall-slab connection or to the connection of other types of concrete components. This embodiment utilises similar components to the first embodiment and like numerals are used to represent like parts. 10 Prime symbols (') are used to indicate where the parts have been modified to adapt to this embodiment. The first wall panel 118' is provided with two pins 122 which are located in spaced disposition at intermediate locations along a first edge 116' of the panel 118'. The first edge 116' faces a second edge 120' on the other wall panel 118" and the two 15 edges have a complimentary profile as illustrated in Figure 25. At corresponding heights along the second edge 120' are located two locking members 126' which are adapted to receive respective heads 124 of the pins 122 in a similar manner as described in the first embodiment. Each of the locking members 126 is connected to the threaded rod 128' by means of two short portions of cable 150 and 152 as shown most clearly in 20 Figures 27 and 28. Figures 27 and 28 illustrate the detail of the modified concrete component connecting system 110'. In this embodiment, the locking members 126' still comprise a part-cylindrical shell 134'. However, instead of being pivotally connected to the threaded rod 128', the part-cylindrical shell 134' is connected by means of two short cable 25 portions 150 and 152. The first cable portion 150 is connected to the perimeter of the cylindrical shell 134' at one edge of the gap 140' formed in the part-cylindrical shell 134' by a swaged connection 154. The first cable portion 150 then passes around an upper side of a cable guiding pin 156. The first cable portion 150 then passes downwardly to be connected to the threaded rod 128' at a first forged steel sleeve 158.

WO 2009/015433 PCT/AU2008/001105 22 The second cable portion 152 is connected to the perimeter of the part-cylindrical shell 134' at the upper edge of the gap 140', where the second cable portion 152 is swaged at 160 as shown. The second cable portion 152 then passes under the cable guiding pin 156 and then passes upwardly to be connected to the threaded rod 128' by 5 a second forged steel sleeve 162. The second forged steel sleeve 162 is above the first forged steel sleeve 158. As shown in Figures 27 and 28, the threaded rod 128' may be housed in a PVC conduit 164. Figure 27 also illustrates the location of the threaded nut 166 at the top of the threaded rod 128'. In this embodiment, the threaded nut 166 is received within a 10 recess 168 formed in the third edge 130' of the wall panel 118". By rotating the threaded nut 166, the threaded rod 128' may be drawn upwardly. As the threaded rod 128' is drawn upwardly, so to are the forged steel sleeves 162 and 158. The raising of the second forged steel sleeve 162 will draw the second cable portion 152 to pass underneath the cabling guiding pin 156 and draw the swaged end 160 towards the 15 cable guiding pin 156. This will urge the part-cylindrical shell 134' to rotate about the spigot 136' in the clockwise direction. At the same time, the swaged end 154 of the first cable portion 150 will be drawn in a clockwise direction and the cable 150 will pass over the cable guiding pin 156. This passage of the first cable portion 150 is facilitated by the upward movement of the forged steel sleeve 158. The part-cylindrical shell 134' will thus 20 adopt the position illustrated in Figure 28. This system has some benefits over the previous embodiment of the concrete component connecting system 110 because in this embodiment, the part-cylindrical shell 134' may be moved to the locked configuration shown in Figure 28 and also reverted to the unlocked configuration shown in Figure 27. To revert to the unlocked 25 configuration, the threaded nut 166 is rotated in the opposite direction to move the threaded rod back down again. Thus, the downward movement of the first steel sleeve 158 will tend to draw the first cable portion 150 over the top of the cable guiding pin 156, thus drawing the part-cylindrical shell 134' in the anticlockwise direction about spigot 136'.

WO 2009/015433 PCT/AU2008/001105 23 Figure 28 shows some other features of the connecting system 110' which may be adopted. Beyond the nut 166, the threaded rod 128 may extend through a roofing truss 170 which is placed on top of the third edge 130'. The threaded rod 128' may pass through the roofing truss 170 where it is received by another threaded nut 172. The 5 threaded nut may be rotated by the use of a hollow tube spanner 174. The existence of the threaded rod 128' above the nut 172 can provide evidence of the relative position of the rod 128' and that will provide some indication as to whether or not the part cylindrical shell 134' has engaged with the locking pin 122. For greater certainty, the locking member 126' may include an indicator to 10 indicate whether or not the part-cylindrical shell 134' has moved to the locked configuration (See Figure 29). The part-cylindrical shell 134' may include a pair of diametrically aligned grooves 180. Further, the locking member 126' may include a non moveable part which is provided with a second pair of diametrically aligned grooves 182. The non-moveable part may be provided as part of the plastic void former 132'. 15 When the part-cylindrical shell 134' is rotated from the unlocked configuration to the locked configuration as shown in the right-hand side of Figure 29, it will be understood that the grooves 180 will align with the grooves 182. The alignment of the two pairs of grooves 180, 182 can be visually inspected when an inspection shaft (not shown) is provided in the panel 118", the inspection shaft 20 having a longitudinal axis which aligns with the axis of rotation of the part-cylindrical shell 134'. The inspection shaft may comprise simply a cylindrical void extending through the side wall panel 118" to check the position of the part-cylindrical shell 134' and thus verify that engagement with the pin 122 has taken place. The inspection shaft may be formed by a PVC conduit which is put in place prior to casting. 25 The inspection shaft may also be put to use when one of the locking members 126' fails to engage. The locking member 126' may be provided with a hexagonal spigot 184 which may be manually rotated to rotate the part-cylindrical shell 134', in the event that it fails to rotate, due to some malfunction of the concrete component connecting system 110'.

WO 2009/015433 PCT/AU2008/001105 24 The inspection shaft may facilitate visual inspection of the locking mechanism or give a tactile indication. For example, the inspection shaft may receive an insert (not shown). The insert may have a key which engages with the pairs of grooves 180, 182 if and only if they are correctly aligned. The insert may be in the form of a plastic plug which 5 remains in the inspection shaft to seal the inspection shaft once the inspection is complete. Reverting to Figures 23 and 24, it can be seen, that in addition to the two locking mechanisms provided at the abutting first and second edges 116' and 120', a locking mechanism is also provided at a fourth lower edge 186 of the panel 118". The locking 10 mechanism includes a locking member 126". This locking member 126" is similar to the locking member 126' in that it uses two cable portions. However, the location of the cable guiding pin 156 is different. The locking member 126" engages with a pin 122 provided in slab 112. The locking member 126" can be locked and unlocked as described above in connection with Figures 27 and 28. 15 The foregoing only describes only one embodiment at the present invention and modifications may be made thereto without departing from this scope of the invention.

Claims

1. A connecting system for cementitious precast components including: first and second precast cementitious components adapted to be arranged in abutting relationship in an assembled configuration, the first and second precast 5 components having respective first and second edges which face each other in the assembled configuration; and a locking mechanism including mutually engageable components disposed at the facing edges, the locking mechanism including a remote actuating means to effect locking of the mutually engageable components at or beyond a third edge of one of the 10 first and second precast concrete components, to secure the first and second precast components together.

2. The connecting system as claimed in claim 1 wherein the two precast components are arranged side by side to one other and the third edge is on top of one of the components. 15

3. The connecting system as claimed in claim 1 wherein the precast concrete components are arranged one atop the other and the third edge is atop the upper component.

4. The connecting system as claimed in any one of the preceding claims wherein the locking mechanism includes: 20 a pin having a head extending from the first edge of the first component; and a locking device including a locking member which is disposed at the second edge of the second component, the locking member being moveable between an unlocked configuration and a locked configuration whereby it is adapted to receive the head of the pin, the locking device further including an elongate member connected to 25 the locking member and extending to the third edge of the second component, wherein WO 2009/015433 PCT/AU2008/001105 26 operation of the locking member may be effected from the third edge by the elongate member.

5. The connecting system as claimed in claim 4 wherein the pin is cast into the first component and a semicircular recess is formed about the pin such that it does not 5 protrude beyond the main surface of the first edge.

6. The connecting system as claimed in claim 4 or 5 wherein the locking member is rotatable about a pivot axis for movement between the unlocked configuration and the locked configuration.

7. The connecting system as claimed in claim 6 wherein the locking member has 10 axial spigots.

8. The connecting system as claimed in claim 7 wherein the axial spigots are received into a shaped plastic spacer which is cast into the second component.

9. The connecting system as claimed in any one of claims 6 to 8 wherein the locking member is a part-cylindrical shell, with the pivot axis defined at the rotational 15 centre thereof.

10. The connecting system as claimed in claim 9 wherein the part-cylindrical shell is one-half to two-thirds of a cylindrical wall, with a gap defined in the cylindrical wall to receive the head of the pin.

11. The connecting system as claimed in any one of claims 4 to 10 wherein the 20 elongate member comprises a rod or a bar.

12. The connecting system as claimed in any one of claims 6 to 10 wherein the elongate member comprises a rod or a bar and wherein the locking member is interconnected with the rod or bar such that lineal movement of the rod or bar effects rotational movement of the locking member. WO 2009/015433 PCT/AU2008/001105 27

13. The connecting system as claimed in claim 12 wherein the elongate member is pivotally connected to the locking member.

14. The connecting system as claimed in claim 12 wherein the elongate member is connected to the locking member through one or more cable portions. 5

15. The connecting system as claimed in claim 14 wherein there are two cable portions allowing movement of the locking member between the locked configuration and the unlocked configuration and also between the unlocked and the locked configuration.

16. The connecting system as claimed in any one of claims 4 to 15 wherein there is a 10 plurality of said locking members, each of which are connected to a common elongate member.

17. The connecting system as claimed in any one of claims 4 to 16 wherein the first component is a slab or footing and the second component is a wall panel and the elongate member extends upwards through the height of the wall panel and is 15 connected to a roofing component.

18. The connecting system as claimed in any one of the preceding claims wherein one of the concrete components includes an inspection shaft to check the configuration of the locking mechanism.

19. A locking device for use with a precast concrete component to lock the 20 component to another precast concrete component, the device including a locking member adapted to receive the head of a pin extending from the edge of the other component; and an elongate member connected to the locking member, the elongate member being adapted for remote operation of the locking member.

20. The locking device as claimed in claim 19 wherein lineal movement of the 25 elongate member effects operation of the locking member. WO 2009/015433 PCT/AU2008/001105 28

21. The locking device as claimed in claim 20 wherein the locking member is rotatable about a pivot axis for movement between the unlocked configuration and the locked configuration.

22. The locking device as claimed in claim 21 wherein the locking member is a part 5 cylindrical shell, with the pivot axis defined at the rotational centre thereof.

23. The locking device as claimed in any one of claims 20 to 22 wherein the elongate member comprises a rod or a bar and wherein the locking member is interconnected with the rod or bar such that lineal movement of the rod or bar effects rotational movement of the locking member. 10

24. The locking device as claimed in claim 23 wherein the elongate member is pivotally connected to the locking member.

25. The locking device as claimed in claim 23 wherein the elongate member is connected to the locking member through one or more cable portions.

26. The locking device as claimed in any one of claims 20 to 25 wherein there are a 15 plurality of said locking members, each of which are connected to a common elongate member.

27. A building panel which is generally planar in form, having a core which is substantially planar in form with opposite sides, the core being substantially aligned with the plane of the building panel, with cementitious material disposed on both sides of the 20 core, the core being formed with a series of substantially parallel open channels which are arranged with the openings on alternate sides of the core, some of the channels being filled with the cementitious material.

28. The building panel as claimed in claim 27 wherein the core has top and bottom edges and the channels extend from the top to the bottom edges of the core and are 25 substantially aligned with the height dimension of the building panel. WO 2009/015433 PCT/AU2008/001105 29

29. The building panel as claimed in claim 27 or 28 wherein the core extends from one lateral edge of the building panel to the other.

30. The building panel as claimed in claim 27 or 28 wherein the building panel is of a width to accommodate a plurality of cores arranged in side by side abutting relationship 5 and extending from one lateral edge of the building panel to the other.

31. The building panel as claimed in any one of claims 27 to 30 wherein the core has top and bottom edges and the building panel has top and bottom edges, the top and bottom edges of the core being spaced from the top and the bottom edges of the building panel thereby defining beams of cementitious material adjacent the top and 10 bottom edges of the building panel.

32. The building panel as claimed in any one of claims 27 to 31 wherein the core is corrugated.

33. The building panel as claimed in claim 32 wherein the core is of a regular zig-zag formation. 15

34. The building panel as claimed in any one of claims 27 to 33 wherein the core comprises insulative material.

35. The building panel as claimed in claim 34 wherein the core is formed of rigid cellular plastics material, preferably expanded polystyrene, expanded polypropylene or expanded polyethylene. 20

36. The building panel as claimed in any one of claims 27 to 35 wherein the building panel includes reinforcing material and the core is provided with holding means for the reinforcing material.

37. The building panel as claimed in any one of claims 27 to 36 further including void formers in the form of inserts which fit with or into the channels in the core to preclude 25 one or some of the channels from being filled with cementitious material to facilitate the creation of service ducting. WO 2009/015433 PCT/AU2008/001105 30

38. The building panel as claimed in any one of claims 27 to 37 wherein the panel also includes a lifting bracket comprising one or more lifting rods extending into the channels and embedded in the cementitious material.

39. The building panel as claimed in any one of claims 27 to 38 wherein different 5 grades of cementitious material are used on either side of the core.

40. The building panel as claimed in claim 39 wherein the building panel has a higher density cementitious material on one side of the core and relatively lower density cementitious material on the other side of the core.

41. A building constructed using a plurality of building panels as claimed in claim 40 10 wherein the building panels are installed with the higher density cementitious material on the inside of the building and the relatively lower density cementitious material on the outside of the building.

42. A method of casting a building panel, the method including: using cementitious material of at least two different densities including a relatively 15 higher density material and a relatively lower density material; placing a first layer of the lower density material into a mould; placing a core assembly over the first layer, the core assembly being substantially planar in form; and placing a second layer of the relatively higher density material over the core 20 assembly.

43. The method as claimed in claim 42 wherein the core assembly includes a core which is substantially planar in form.

44. The method as claimed in claim 42 or 43 wherein the core is of a regular zig-zag formation. WO 2009/015433 PCT/AU2008/001105 31

45. The method as claimed in any one of claims 42 to 44 wherein the core is formed of rigid cellular plastics material, preferably expanded polystyrene, expanded polypropylene or expanded polyethylene.

46. The method as claimed in any one of claims 42 to 45 wherein the core assembly 5 includes reinforcing material and the core is provided with holding means for the reinforcing material.

47. The method as claimed in any one of claims 42 to 46 wherein the core assembly also includes a lifting bracket comprising one or more lifting rods extending into the channels and embedded in the cementitious material. 10

48. A method of constructing a building using a plurality of building panels cast according to the method as claimed in any one of claims 42 to 47 wherein the panels are installed with the higher density material on the inside of the building and the lower density material on the outside of the building.