WO2017011861A1

WO2017011861A1 - Method of making a building panel having insert

Info

Publication number: WO2017011861A1
Application number: PCT/AU2016/050629
Authority: WO
Inventors: Timothy Mark GRABHAM
Original assignee: Csr Building Products Limited
Priority date: 2015-07-17
Filing date: 2016-07-15
Publication date: 2017-01-26

Abstract

A method of making a building panel provided with an integral lifting element, such as a lightweight building panel made from autoclaved aerated concrete having an insert provided with exposed ends for engaging with one or more lifting devices, and a central section embedded in the building panel to secure the lifting element to the building panel, includes locating the lifting element in a mold and retaining the lifting element in a correct position and orientation using a retainer. A lower former is positioned in the mold corresponding to the location of an access void into which one exposed end of the lifting element extends, and an upper former is located at the upper end of the mold to engage with the other end of the lifting element to form an access void around the other exposed end of the lifting element. Molding of the access void in the building panel provides clearance for attaching lifting devices to the panel so that multiple building panel is can be lifted in unison.

Description

METHOD OF MAKING A BUILDING PANEL HAVING INSERT

FIELD

The present invention relates generally to building panels, and to methods of manufacturing such panels.

In one form, the present invention relates to the methods of manufacture of lightweight building panels made from autoclaved aerated concrete (AAC) and to such panels made by methods for their manufacture.

In one form, the present invention relates to manufacturing methods of AAC panels having integral lifting elements for use in lifting the panels into place on a building construction, particularly lifting multiple panels simultaneously for installation in multi- storied buildings.

The present invention finds particular application as methods of forming lightweight AAC building panels having a lifting element which can be used to lift the panel along with other similar lightweight AAC building panels simultaneously for individual placement where required, and to methods of positioning and retaining the lifting element in place prior to and during manufacture of the panel.

Although the panel will be described with reference to one or other embodiments of the panel, and to one or other methods of manufacturing the panels, it is to be noted that the scope of protection is not restricted to the described embodiment or embodiments but rather protection is more extensive so as to include other steps and variations in the manufacturing process and of the panel and of the lifting element, and to uses of the processes and panels and/or lifting elements other than specifically described.

BACKGROUND During construction of buildings, particularly multi-story buildings, there is a need to lift building panels used in the construction of the building from ground level to locations where the building panels are to be installed in the building, including lifting the panels to upper levels of the building well above ground level.

In the past, it has been necessary to lift a single panel only at any one time so that the panel could be placed at a specified final location within the building as required. It was only after the panel had been installed at the desired final location that the lifting apparatus was free to return to ground level and another single panel lifted into place for installation at the new desired final location, typically close to the previously lifted and installed panel. Thus, it was usual to lift a single panel only during a lift.

However, lifting individual panels one at a time is time consuming and hence costly, adding to the overall cost of construction of the building. Accordingly, there is a need to reduce construction costs by lifting more than a single panel at a time.

However, previous attempts to lift more than a single panel at the same time, such as groups of panels have not been entirely successful for one reason or another due to difficulties in controlling movement of the individual panels of the group, difficulties in connecting the panels to each other allowing for separate placement of the individual panels one at a time at their respective final locations, lifting the weight of a group of panels simultaneously and complying with the relevant provisions of the rules and regulations concerning lifting building panels at construction sites, including satisfying Occupational Health and Safety requirements, particularly relating to lifting operations.

More particularly, previous attempts at lifting multiple panels simultaneously have not allowed separate placement of one panel or the one group of panels at a time at different respective final locations for the individual panels or group of panels depending upon where the panels were required for installation but rather all of the multiple panels required unloading at the same intermediate location due to the equipment and method used for individually lifting the panels.

Once the individual panels were unloaded as a group at the one intermediate location, the panels needed to be repositioned manually by workers stationed in close proximity to the multiple panels, such as for example, at an upper level of the building being constructed. Whilst the use of such equipment and methods saved some time in actually lifting the panels, extra time and workmen were needed at the intermediate location to manually reposition the panels once deposited at the upper level so that overall there was little cost savings in construction costs because there was only a slight improvement in the time taken to position the individual panels at their respective final locations.

Other attempts at lifting multiple panels simultaneously included tethering individual panels to each other so that a plurality of panels were interconnected by tethers, such as flexible tethers, including straps, chains or similar. While the use of such systems allowed the placement of single panels individually one at a time at different locations by operators being able to disconnect the panels from each other as required, there were major safety concerns over lifting multiple panels in an unrestrained

interconnected series or sequence in which the individual panels were able to move more or less independently of one another, even when interconnected to each other, since in adverse weather conditions, due to the panels being somewhat unrestrained there could be unwanted movement of one or more of the panels, sometimes dangerously so, such as for example, unacceptably large relative movements in windy conditions as the panels swayed from side to side while being lifted into place. In some circumstances, there was a sufficiently large range or amplitude of movement of the panels for the panels to strike or collide with each other or with parts of the building undergoing construction, or with parts of the lifting apparatus, since there was little or no control of movement of the respective panels, particularly the lower panels in the series or sequence when actually being lifted into place by the lifting apparatus, even if guy ropes or wires or stays were used to constrain movement of the individual panels in the interconnected sequence.

Furthermore, in configurations where individual panels were flexibly tethered to one another, only two or three individual panels at most, could be lifted in the one lift owing to the overall distance occupied by the panels due to the required separation of the panels from each other, including the distance apart of the individual panels from each other, by the alternating arrangement of flexible tethers and panels forming the sequence of panels being lifted in unison, which made lifting more than, say, three panels simultaneously, unwieldy and/or dangerous because of the distance extending between the lower edge of the lowermost panel and the upper edge of the uppermost panel, including the space occupied by the various components of the lifting apparatus.

Therefore, there is a need for a panel which can be lifted as part of a group of panels in a single lift of the lifting apparatus and individually placed as a single panel or small set of panels at a desired location, and for methods of making such panels that can be lifted in this manner.

Accordingly, it is one aim to provide a building panel having a dedicated lifting element allowing multiple panels to be lifted simultaneously and unloaded individually or as a set for placement at respective different locations and to methods of forming such panels having integrated lifting elements capable of being lifted in this manner.

Accordingly, it is an aim of the present invention to provide a method of manufacturing a building panel associated with a lifting element for allowing multiple panels to be lifted simultaneously and placed individually or as a set at respective different locations.

Accordingly, it is an aim to provide a method of transporting a building panel in a group of multiple panels in such a manner to lift the multiple panels as a group of panels for individual placement of the panels singly at different respective locations. Accordingly, it is an aim to provide a panel having a lifting element for cooperative engagement with a lifting device for use in lifting multiple panels having respective lifting elements simultaneously engaged whilst allowing individual panels or a set of panels to be placed separately at respective different locations.

It is to be noted that not all embodiments of the panel and/or of the lifting element and/or of the various manufacturing methods or steps will satisfy all aims. One embodiment will satisfy one aim, whereas another embodiment will satisfy a different aim. Some embodiments will satisfy two or more aims.

SUMMARY

According to one form of the present invention, there is provided a method of making a building panel having at least one lifting element, the panel having a body portion generally defining the shape of the panel, and the body portion having at least a first surface associated with the lifting element, the method comprising the steps of providing a mold generally for forming the shape of the body of the panel, locating the lifting element at a predetermined location and in a preselected orientation within the mould, the lifting element having a first part and a second part, securing the first part of the lifting element within the mold to maintain the predetermined position and orientation of the lifting element during formation of the panel, forming the body of the panel generally in accordance with the shape of the mold, wherein the position and orientation of the lifting element is such that the first part of the lifting element is secured to the body of the panel when moulded and the second part of the lifting element is accessible from outside the first surface of the body of the panel when formed, the second part of the lifting element being provided with an engager for selective cooperative engagement with a lifting device to facilitate lifting of the panel.

According to one form of the present invention, there is provided a building panel comprising a body portion generally in the shape of the building panel, the building panel having at least a first surface, the first surface being associated with at least a first lifting element for use in lifting the building panel, the lifting element having a first part for secure attachment of the lifting element to the body of the building panel in the region of the first surface to fixedly locate the lifting element with respect to the panel for facilitating lifting of the panel, the lifting element having a second part accessible from outside of the first surface of the building panel for cooperation with an external lifting device to lift the panel using the lifting device when connected to the lifting element, wherein the second part of the at least first lifting element is provided with an engager for selective cooperative engagement with the lifting device such that when the lifting device is connected to the engager of the first lifting element, the panel moves in response to corresponding movement of the lifting device to move the panel.

BRIEF DESCRIPTION OF EMBODIMENTS

In one form, the building panel is a lightweight building panel, in the form of a slab, block, or other generally rectangular prism or cuboid shape, such as a substantially cuboid building panel having two opposed faces, being an obverse face and a reverse face, two opposed longitudinal sides in spaced apart relationship to each other, one on either side of the panel, and two opposed transverse sides or ends in spaced apart relationship to each other, on or at either end of the panel, in which the length of the longitudinal sides is greater, preferably considerably greater, than the length of the transverse ends, wherein in forms of the panel, all of the longitudinal sides and transverse ends extend substantially perpendicularly between the two opposed faces.

However, shapes other than rectangular prisms are possible.

More typically, the building panel is a parallelepiped lightweight building panel. Even more typically, the building panel is a lightweight slab building panel, typically an autoclaved aerated concrete panel (AAC panel). Preferably, the lightweight building panel is an AAC panel supplied, manufactured and/or available from CSR Building

Products Limited, under the name "Hebel®, including panels marketed under the following names, "Hebel® powerpanel", "Hebel® power floor", "Hebel® solid panel", "Hebel® power floor+", "Hebel® commercial floor", "Hebel® Smartslab", "Hebel® Powershield" or similar.

Forms of the panel are provided with smooth faces, edges, ends or sides. Forms of the panel are provided with cooperating complementary tongue and groove arrangements along the long sides or short sides or both the long and short sides of the panel.

Forms of the panel have surface decorations on the faces, including combinations of depressions and projections, or depressions and flat surfaces, such as by selective routing of the faces.

The rectangular building panels can be arranged to form a floor or a wall of a building, including a single storey building or a multi-story building requiring the panels to be lifted into place for installation on or in the building during construction of the building.

In one form, the panel is provided with one or more rebates, channels or grooves. Typically, there are two rebates, channels or grooves, one on either side of the panel, typically, on each of the long sides, more typically on, at or towards the upper corner or edges of both long sides.

In one form, the building panel is provided with two rebates, preferably one rebate being located along one side or edge and another rebate being located along another side or edge, more preferably on opposed sides or edges, such as on the two longitudinal edges or along the two longitudinal corners of one face of the panel, more preferably the upper face in use of the panels.

In one form, the two opposed rebates have the same shape, profile, cross-section or similar, whereas in other forms, the opposed rebates have different shapes, profiles, cross-sections or similar.

In one form, the rebate has two parts, an upper part and a lower part. Typically, the width of the upper part, closer to the top face of the panel is smaller than the width of the lower part which is closer to the bottom face of the panel. More typically, the upper and lower parts are angularly inclined to one another. Typically, the upper and lower parts are angularly inclined to each other in opposite directions to form a waistline immediate the two parts, typically at the junction of the two oppositely inclined parts. More typically, the upper part is inclined at an angle of between about 100° and about

135° to the top face and the lower part is inclined at an angle between about 10° and 45° to a plane parallel to the upper face. However, the parts of the rebate can have any suitable inclination to one another and to the faces or edges of the panel.

In one form, the rebate has a generally part circular or curved shape or profile, typically a semicircular or half round shape or profile when viewed in cross-section. Typically, this form of rebate is located in one longitudinal side closer to the obverse face of the panel i.e. the upper or outer face in use.

One form of the panel has a single lifting element whereas other forms of the panel have two or more lifting elements, typically multiple lifting elements. In one form the multiple lifting elements, if provided, are substantially the same. If there are two or more lifting elements provided, the elements are typically located in spaced apart relationship to one another. More typically, the lifting elements are located at symmetrical locations within the panel, even more typically symmetrically about the midpoint or midplane of the panel, preferably about the transverse midplane of the panel located towards the transverse sides or ends of the panel. More typically, the lifting elements are in spaced apart substantially parallel relationship to each other.

Forms of the lifting element include a single elongate lifting insert or similar which extends transversely from one side of the panel to the opposite side of the panel through the entire width of the panel. Other forms of the lifting element include inserts formed from two or more segments or sections which are placed in effect to combine to form the lifting element in which one segment is located at or towards one side of the panel, typically one of the longitudinal sides or edges of the panel, and the other segment is located at or towards the opposite longitudinal side or edge of the panel so that one segment extends from and is accessible at one side of the panel and the other segment extends from and is accessible at the other side of the panel. In one form, the two segments on either side of the panel are in alignment with each other, such as for example, being collinear, whereas in other forms, the two segments are off-set from each other by being spaced laterally from each other. In one form, the inserts extend from alternating sides of the panel in sequence in staggered relationship.

Forms of the lifting element extend outwardly from the respective longitudinal edge or side, typically so as to be accessible from outside the panel by being located in a void, typically an access void, or similar provided at the side or edge of the panel, such as for example, formed in the side or edge of the panel as the panel is being

manufactured, typically as the panel is being molded. The second section of the same lifting element or the two segments of the lifting elements have exposed ends at the respective sides of the panel, typically located in access voids formed or molded in the sides or edges of the panels during manufacture of the panels. It is to be noted that the voids can be formed around the ends of the insert after the panel has been manufactured and/or cut to shape and size.

One form of the lifting element is an insert located partially within the panel. Forms of the insert are metal rods, bars, channels, grooved sections, typically channel sections having a U-shaped profile, a C-shaped profile or the like including having a web section located between two spaced apart side walls or flanges extending from the web section in either side of the insert, typically substantially perpendicularly from the web section. However, the insert can have any suitable or convenient transverse shape or profile, including being symmetrical about the centre line or asymmetrical about the centre line.

In one form, the lifting element or insert has two end sections or two outer sections, or two exposed end sections which are exposed at either end, and a central or inner or midsection which is located internally within the panel, such as for example, by being embedded within the panel. In other forms, such as the segment form, the insert has a single exposed outer end and a single inner end embedded within the panel.

In one form, the central section or portion, or inboard end or portion, is located within the body of the panel, typically embedded within the material from which the panel is made, such as embedded or enclosed within the AAC mixture from which the panel is made. The outer end or end portions or sections of the lifting elements are exposed by extending outwardly from the sides of the panel, typically being exposed within the access voids in the sides of the panels. In forms of the panels, the inserts or lifting elements are arranged in alignment with the access voids, which in one form are cut-outs, rebates, cavities, spaces, gaps, concavities, or similar. The access void can have any suitable or convenient shape for allowing attachment of the lifting device to the exposed end of the insert and/or release of the lifting device from the exposed end of the insert, including having sufficient clearance around the exposed end of the insert to engage more than a single exposed end of respective inserts, in the event that the panels, when in the stacked array, are not perfectly in alignment with each other so that the position of the exposed ends of the inserts are located offset from each other. Forms of the accessible ends of the exposed ends of the lifting element are provided with an engager for engaging a suitable lifting device, such as for example, a lifting bracket, a lifting arm, a lifting leg, a lifting tool, a lifting assembly having a fixed part and a movable part for selectively engaging the engager or the like. Forms of the engager which are selectively cooperatively engageable with the lifting device, include an end profile for facilitating engagement of the insert with the lifting device. One form of the end profile is tapered, bevelled, inclined, sloping or the like, particularly the distal ends of the walls of the insert and/or to assist in manufacture of the panel. However, another form of the end profile is straight or perpendicular to the lengthwise extending axis of the insert in order to assist in alignment of the lifting device with the exposed ends of the inserts collectively of the stacked array of panels, and

engagement/disengagement of the lifting device from the lifting device and/or engager.

In one form, the engager is an aperture, opening, hole, bore, perforation, cavity, void, or similar. In one form, the engager is a projection including a pin, peg, boss, spigot, rod, tube, stub, or the like. However, the engager can have any suitable shape, profile, type, configuration or the like for cooperative engagement with the tool. It is to be noted that the cooperative part of the lifting tool and the engager are complementary to one another, whatever their respective form.

In one form, the insert forming the lifting element is typically in the form of a channel section having a central web located between two side walls, typically in the form of a flange at either side of the insert. Forms of the insert are provided with one or more retainers for assisting in retaining the channel section embedded within the AAC mixture typically, during and after manufacture of the panel. In one form, the retainers provided on the lifting elements cooperatively engage with the reinforcement incorporated within the shaped body of the panel. Typically, the reinforcement is a mesh, such as a reinforcing mesh, typically, in the form of a mesh of a single sheet or in the form of a cage having two or more sheets or layers or screens interconnected together. Typically, the mesh in the form of a sheet or cage is composed of rods, bars, tubes, or the like, preferably round rods, circular rods, or the like arranged in an interconnected array or grid-like pattern or arrangement. In one form, the retainers extend at least partially out of the plane of the lifting element, typically by being stamped from the web portion or wall portion of the channel section.

In one form, the retainer is a projection, protrusion or other fitting extending outwardly from the insert. Forms of the retainer include a metal hook, fastener, clamp, clip, barb, tongue, cleat, spike, tooth or the like having a shank portion and a tip portion. Forms of the shank portion can be straight or curved, typically, an outward curve, an "S" shaped compound curve, or be divergent or convergent with the body of the channel section. Typically, the shank is in the form of a single segment, or two or more segments which may be inclined to each other. Typically, the hook is movable, and the tip portion is able to be deflected, typically being resiliently deflectable, or deformable so as to move slightly to pass over a circular rod of the reinforcing mesh and to resiliently spring back into place when the tip of the hook clears the circular rod of the mesh in order to retain the rod closer to the root of the hook, clip or similar in the space between the web or wall of the insert and the shank of the hook.

Forms of the lifting element are positioned at a predetermined location within the mold or similar for forming the panel. In one form, the lifting element is located at or towards one or other or both transverse ends. Forms of the lifting element are oriented to extend substantially transversely through the width of the panel. However, in other forms of the panel, the lifting element extends substantially longitudinally or substantially obliquely from one end of the panel to the other end of the panel, or from one side of the panel to the other side of the panel, or to extend from both sides or both ends of the panel, or from one end and one side of the panel. In one form, the orientation of the lifting element is such that the channel section of the insert extends substantially parallel to the side walls of the mold which in one form of the mold, are substantially vertical.

In one form, the individual members or rods of the mesh assist in retaining the channel section in the correct orientation prior to and/or during manufacture of the panel.

Typically, the individual rods or bars of the mesh cooperatively engage with retainers provided on the lifting element to assist in locating and positioning the lifting element in the correct location and orientation.

Forms of the lifting element have two, three, four or more retainers located in spaced apart relationship to one another in the longitudinal direction of the elongate lifting element. In one form, the spacing of the retainers corresponds to the spacing of the rods or bars of the reinforcement mesh or the like, including the spacing of the rods or bars being regular or irregular, such as when pairs of lengthwise extending rods have a first spacing within each pair, i.e. intra pair spacing, and a second spacing between adjacent pairs of rods, i.e. inter pair spacing.

In one form, the AAC mixture or fluid is formed into a block within the mold. Typically, the AAC block is sliced to form a multitude of slabs, typically substantially identical slabs, which are then optionally cut or trimmed to size, firstly to form a pre-form for the panels and then subsequently to form individual panels.

Typically, the longitudinal cuts to form the block into panels is between layers or sheets of reinforcements which extend in spaced apart substantially parallel relationship to each other in their lengthwise extending direction.

In one form, the mold is a disassemblable mold in the form of a box having sides and/or ends which are removable, such as for example, by being collapsible or disassemblable.

In one form, the base of the mold is movable or connected to a movable assembly, typically a movable carriage for travelling along rails to transport the mold, the base of the mold, or the block, or the multitude of panels. In one form, there is a lower former, typically, more than one lower former, preferably a pair of spaced apart substantially parallel lower formers. In one form, the lower formers are located at or near to the ends of the mold. However, it is to be noted that the formers can be located anywhere on the base of the mold.

Typically, the position of the formers is symmetrical about the transversely extending mid plane of the mold or of the block being formed in the mold.

In one form, the former is provided with at least one receiver for receiving the end of the insert, typically, multiple receivers for receiving the ends of respective inserts to assist in securing the inserts prior to and during formation of the panel. In one form, the former has up to about ten or more receivers, typically from about 5 to about 10 receivers, more typically about seven receivers arranged in spaced apart relationship to each other. It is to be noted that the number of receivers corresponds to the number of individual inserts being secured in place within the mold.

Forms of the receivers include slots, cut-outs, rebates, grooves, channels, or the like, typically, the grooves in the form of C-shapes, U-shapes, L-shapes or the like. Forms of the receivers, particularly the shape or profile of the receivers, correspond in shape to the cross-section of the inserts. In one form, the receiver has three parts arranged to extend substantially at right angles to each other to form a C- or U-shape.

Other forms of the receivers include projections for connecting to the inserts, typically to the apertures of the ends of the inserts. In one form, the projections are fasteners, clips, clamps or the like.

In one form, the former is of a generally trapezoidal prism shape having a base or lower surface of greater dimensions than the top or upper surface.

In one form, the lower former is partially hollow, being provided with cavities, chambers, or openings, typically internally arranged, such as for example, to save weight and/or material. In some forms, the lower formers are not used but an alternative method of loading the lower ends of the inserts is used.

In one form, the location of the lower formers corresponds to the location of the access voids on one long side of the panels.

In one form, the mold includes side walls, typically removable or collapsible side walls. In one form, the side walls are substantially smooth sided. Typically, the smooth side of the wall faces internally into the chamber of the mold for forming the sides or side edges of the panels.

In one form, the side walls are provided with a fitting for cooperatively engaging with the upper former, typically for cooperatively engaging with the end extension of the upper former which end extension is provided to extend outwardly from both ends of the upper former. In one form, the end extension of the upper former includes projections, protrusions, or similar. Forms of the extensions include pins, pegs, extensions, rods, arms, tubes, axles, stubs, supports or the like.

In one form, the fitting of the side wall for cooperatively engaging with the upper former are supports. Forms of the support include notches, grooves, cut-outs, voids, channels, rebates, slots, or the like located in at or along the edge of the side wall, typically, in the upper edge or upper surface of the side wall. In one form, there are two supports on either side of the mold, typically, located at spaced apart locations along the top edge of the side wall. More typically the two supports are aligned with each other so as to engage with the upper former which extends transversely between the two walls of the mold. In one form, the slot or notch has a rectilinear profile, typically a square or rectangular profile, cross-section or shape.

In one form, the notches or slots are positioned to correspond to the position of the upper former, typically in alignment with the upper former so that the pins extending from the ends of the upper former are received in the notches or slots to prevent unwanted movement of the elongate inserts, formers, mesh reinforcing or similar to retain the individual panels in aligned position with the mold.

In one form, the support is a single elongate bar, rod, tube or similar spanning the entire width of the former and is provided with the outwardly extending pins or pegs at either end. In this form, the elongate bar is received within a recess extending lengthwise of the former. The recess has a size, shape and profile corresponding to the size, shape and profile of the elongate bar.

In one form of the support there are two separate supports, one extending from each side of the upper former, the two supports in the form of pins being collinearly aligned with each other to extend on opposite sides of the upper former. In one form, the support is in the form of a block, typically in the form of a generally rectangular or shaped block for being received in correspondingly shaped recesses or cavities at either side of the upper former. A pin, peg or similar extends from one side surface of the block to be received in and supported by the slot or notch.

One form of the upper former is a planar member, typically in the form of a plate. In one form of the plate is a hinged plate or suspended plate. In one form the plate is a downwardly depending plate capable of being flexibly inserted into the mold from above. In one form the plate has a protection, protrusion or extension for forming the access void of the panel. In one form there is a multiplicity of similar downwardly depending hinged plates connected collectively to a gantry. In one form the gantry is lowered towards the mold to insert the plates at the correct location to form the access void at and around the exposed end of the insert.

In one form, the reinforcing mesh is supported by the retainers of the insert spaced apart from the lower former, typically spaced apart from the upper surface of the lower former for defining a gap or space therebetween to allow the flow of fluid mixture in the mold to fill so as to embed the mesh wholly within the AAC material to completely envelope the mesh so that when the slab is cut from the block, there is no part of the mesh exposed.

The AAC mixture can have any suitable components or ingredients and be of any suitable composition. Additives may be included in some compositions, including additives to accelerate or retard curing of the slab, either before, after, or during autoclaving or to impart specialised or specific properties or characteristics to the finished panels.

In one form, there is a membrane located intermediate the lower surfaces of the lower formers and the upper surface of the base of the mold. Typically, the membrane provides a seal between the lower former and the base of the mold to prevent the liquid AAC mixture from flowing past and/or into the internal cavities of the lower former and/or to ensure that the access voids at the sides of the panels are correctly formed in location, shape, profile and size. In some embodiments, the lower formers are provided with an undersurface which is sealed to the base so that the membrane can be omitted. In this embodiment, as the undersurface of the former is sealed to the base, the liquid AAC mixture is prevented from flowing underneath the former.

BRIEF DESCRIPTION OF DRAWINGS

Forms of the building panel and methods of manufacturing the panels having forms of the lifting elements will now be described to illustrate embodiments of the panel and their method of manufacture with reference to the accompanying drawings in which: Figure 1 is a perspective view of one form of the building panel having one form of the lifting element embedded therein.

Figure 2 is an enlarged view of circle A of Figure 1 showing the relationship between the exposed end of the lifting element and the corresponding access void.

Figure 3a is a top plan view of the building panel of Figure 1 showing one form of the lifting element in dotted outline.

Figure 3b is a top plan view of another form of the building panel showing another form of the lifting element in dotted outline.

Figures 4a and 4b are side elevation views of opposite longitudinal sides of the panel of Figure 1 showing the different profiles of the two rebates extending lengthwise the panel. Figures 5a and 5b are end elevation views of either end of the panel of Figure 1 showing the profiles of either longitudinal side of the panel.

Figure 6 is a perspective view of one form of the lifting element in the form of a channel section having four spaced apart retainers. Figure 7 is a top plan view of the panel of Figure 1 showing one form of the mesh reinforcement in phantom and two different forms of the lifting element embedded within the panel.

Figure 8 is a side elevation view of the panel of Figure 1 showing the mesh in phantom embedded within the panel and the exposed ends of the two forms of the lifting element.

Figure 9 is an enlarged view of circle B of Figure 8.

Figure 10 is an end view of the panel of Figure 1 showing the mesh reinforcement in phantom.

Figure 1 1 is an enlarged view of circle C of Figure 10 showing the engagement of one of the hooks of the lifting element with one of the rods of the reinforcement mesh.

Figures 12a, 12b and 12c are side views of one form of the retainer of the lifting element in the process of engaging with a rod of the reinforcement mesh to secure the lifting element to the mesh when in the mold.

Figure 13 is a perspective view of part of the mold showing a pair of spaced apart lower formers for receiving the lifting elements.

Figure 14 is a partial perspective view of the mold showing a pair of spaced apart upper formers being located in place to retain the multitude of lifting elements in place in the mold with the lifting elements extending from respective lower formers.

Figure 15 is a partial cross-section through one form of the lower former. Figure 16 is a partial cross-section through one form of the upper former.

Figure 17 is a perspective view of the mold ready to receive a mixture for forming the panel of Figure 1 . Figure 18 is a perspective view of four panels of Figure 1 in stacked abutting relationship one upon the other showing the exposed ends of the lifting elements of the respective panels in more or less vertical alignment with each other.

Figure 19 is a perspective view of another form of the upper former for forming the access voids within which the exposed ends of the lifting elements are located.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One embodiment of a building panel, in the form of a light weight flooring panel will now be described in detail. It is to be noted that the panel can have other forms, including other shapes, such as for example, in the shape of a trapezoidal prism. A lightweight flooring panel, generally denoted as 10 is typically made from a lightweight structural building material, such as autoclaved aerated concrete (AAC) of the type made by CSR Building Products Limited and available under the name of Hebel®, including variations thereof.

Although the panel will be described by reference to a flooring panel, other forms of the panel can be used as wall panels, particularly as interior or exterior wall cladding in multi-storied buildings.

Panel 10 is of a solid generally rectangular prism shape, such as a general parallelepiped shape or similar having a top or obverse face 12, a bottom or reverse face 14, two longitudinal sides 16, 18 and two transverse ends 20, 22 generally arranged to extend perpendicularly to one another to form a generally rectangular prism shaped slab or similar shape having a length of typically up to about 6 meters, a width of typically up to about 600mm and a thickness of typically up to about 300mm or more. However, panel 10 can be made in any suitable length, width or thickness combination as required depending upon the type of intended use required and the construction method of the building using the panels, such as whether panel 10 is used as flooring with obverse face 12 facing upwards or as wall cladding with observe face 12 facing outwards.

A discontinuity in the form of a rebate, such as a groove or similar is provided along the upper side edge of panel 10 on both sides of panel 10. The discontinuity can take any suitable or convenient form. One preferred form of the rebate is a double profile (DP) groove, notch, or similar 24, extending lengthwise along one of the upper longitudinal side edges or corners of obverse face 12 in use of panel 10, as shown more particularly in Figures 1 , 5a, 5b and 18. In one form, groove 24 is formed from two surfaces angularly inclined to one another to form an angulated groove or groove having an inclined profile. It is to be noted that groove 24, 26 can take any suitable profile, including being of the same general shape or of different shapes.

One form of groove 24 will now be described.

The two inclined surfaces forming groove 24, are an upper surface 28 which is straight sided, or is an undercut surface extending from top face 12 inboard of panel 10 at an angle, in a generally downwards direction away from top face 12, and a lower surface 30 which extends from the inboard lower edge of upper surface 28 to side surface 16 at a downwardly directed angle, also in a direction away from top surface 12. In one form, the junction between upper surface 28 and lower surface 30 is a waist line. In one form, the angle of inclination of upper surface 28 can vary from about 100° to about 135 ° with respect to obverse face 12, and the angle of inclination of lower surface 30 with respect to a plane parallel to the plane of obverse face 12, can vary from about 10° to about 45°. Other inclinations are possible.

It is to be noted that groove 24 provides a longitudinal slot into which part of a ring anchor system can be located, such as for example, an elongate rod or bar to assist in securing panel 10 in place as part of the floor at one level in the multi-storied building. Additionally, it is to be noted that groove 24 is shaped to receive elongate reinforcing bars, tie down bars or other fasteners therein to assist in fastening the flooring panels to the solid substrate of a floor to maintain the flooring panels in position after installation, such as for example, the reinforcing bars forming part of a "ring anchor system" which is anchored by steel cleats located external to the floor substrate or steel framework members, to resist upward movement of the panels from the floor when installed in the building, also to be described in more detail later in this specification.

Another form of the rebate, located on the opposite side of panel 10, but close to the edge of obverse face 12, is a rebate 26 of a generally semi-circular or part round profile. Rebates 24, 26 are shaped so as to cooperatively receive tie down rods or similar therein or therebetween to secure panel 10 within the building.

Panel 10 is provided with one or other form of a lifting element. One form of the lifting element is an insert 40 in the form of a U-shaped channel section having a central web 41 located between two walls 43, extending substantially perpendicularly from the web, typically in the form of flanges located at either side of web 51 .

In one form, insert 40 is a single elongate channel section extending from one long side of panel 10 to the other long side, as shown more particularly in Figure 3a. In another form, the insert is in the form of two spaced apart segments 42, in alignment with each other, extending outwardly on opposite long sides of panel 10 as shown in Figure 3b. Although the insert can have different forms and be made from separate segments, the insert will be described as being a single elongate channel section 40 extending from one longitudinal side 16 of panel 10 to the other longitudinal side 18 of panel 10 for ease of expression and clarity of understanding.

Insert 40 has two exposed ends 44, extending outwardly from respective long sides 16, 18 of panel 10 so as to be accessible from outside of panel 10. Each end 44, is provided with an engager, typically in the form of an aperture 50 for cooperative engagement with a suitable lifting device to lift panel 10.

Panel 10 is provided with a pair of spaced apart access voids 52 on either long side 16, 18. Voids 52 allow access to ends 44 of insert 40 and to apertures 50 for lifting panel 10 such as for example, for the ends of a suitable lifting device to engage with aperture 50. The engager can be of any suitable form, configuration, shape or type. Aperture 50 is preferably circular. However, other forms are possible such as being a slot, or square, rectangular, oval or the like. The distal ends 44 of insert 40 are tapered or bevelled having inclined outer edges in the walls of the U-section forming the insert as shown more particularly in Figures 2 and 6. The inclined edges assist in the manufacture of the panels by helping guide the ends of the insert into the formers located at the base of the mold in spaced apart relationship.

Insert 40 is generally elongate of a size sufficient to span from one long side 16 of panel 10 to the other long side 18 of panel 10. The actual size of insert 40 is determined by the width of panel 10 so that the length of insert 40 substantially corresponds with width of panel 10, and can range from less than about 150mm to more than 600mm.

Insert 40 is provided with a multitude of spaced apart retainers in the form of hooks 46. Each hook 46 is provided with a shank 47 and a tip 48 in which tip 48 is spaced apart from web 41 of insert 40. Hook 46 can have any suitable form. In one form, shank 47 is generally arcuate (not shown) whereas in another form, shank 47 has angularly inclined end and mid segments as shown more particularly in Figures 6, 12(a), 12(b), 5 12(c). Tip 48 at the distal end of shank 47, is bent or otherwise curved inwardly in the direction of web 41 of insert 40 so as to be able to capture and retain a part of the reinforcing mesh embedded with panel 10 as will be described in more detail below.

Void 52 can have any suitable or convenient shape. Void 52 is provided to allow access to end 44 of insert 40 so that a cooperative part of the lifting device can o cooperatively engage with aperture 50 to securely connect the lifting device to panel 10 as will be described in more detail below.

Void 52 is formed using a former placed strategically within the mold. One typical shape of the former is illustrated in the accompanying drawings, particularly Figures 15 and 16. The form of void 52 formed by the formers of Figures 15 and 16 has an

5 outboard tapered wall 54 located towards one transverse end, a central recessed straight wall 56, and an inboard tapered wall 58 located on the other side of the central wall 56, for defining the void.

One form of the former is provided with internal cavities or hollowed sections, typically to reduce the weight of the former, and to reduce the cost of the former by requiring o less material. However, other forms of the former are solid, such as to have increased strength and rigidity depending upon requirements of the molding process, such as for example, the size of the panels being molded.

In one form, void 52 can provide clearance to allow selective access to end 44 of insert 40 at the side of panel 10, particularly to aperture 50 to allow cooperative engagement 5 with a suitable lifting device, typically in the form of a lifting tool, lifting arm, lifting

bracket, or the like having a movable grip or similar in the form of a pin, peg or other projection for being received within aperture 50, to enable a group of individual panels in stacked relationship one above the other, as shown more particularly in Figure 18, to be lifted simultaneously in a single lift and unloaded separately at different respective 0 locations by the lifting tool moving to a disengaged position for disengaging the

movable grip, pin, peg or similar, of the lifting tool from the insert, most notably aperture 50, of the lowermost panel of the stack of panels to allow the lifting tool to be removed from the panel and reconnected to the next lowermost panel in the stack of panels to move the panels to the respective new locations.

Another form of upper former for use in molding access void 52 will now be described with particular reference to Figure 19. This form of the upper former includes a block made from polystyrene or similar material in the shape and profile of access void 52, which is to be formed at spaced apart locations along the longitudinal side of panels 10. The polystyrene block is retained in position by a suitable subassembly. One form of the suitable subassembly for retaining the polystyrene blocks in place within the mold during formation of a block in the form of a pre— form from which individual panels can be produced, is illustrated in Figure 19, which subassembly is in the form of a gantry, that can be raised and lowered to retain and release the polystyrene block in and from the mold as required. Subassembly 86 includes upper framework 88 comprising a pair of longitudinally extending framework members 90a, 90b, and a multitude of transversely extending framework members 92 interconnected together to form a lattice arrangement. A multitude of spaced apart hinged plates 94 downwardly depend from, or are suspended from lower framework member 90b. Plates 94 are spaced apart corresponding to the spacing apart of where access voids 52 are to be formed during the molding process. Plates 94 form access void 52 where required. Plates 94 are provided with an outwardly extending projection 96 of a size and shape corresponding to the size and shape of a receiver formed in the polystyrene block. In one form the receiver includes a slot, groove or similar having the same general shape and profile as the end 44 of insert 40, typically a U-shaped groove or slot within which the upper end of insert 40 is cooperatively received. The polystyrene block has a further slot, typically extending transversely to the part of the slot for receiving the end of the insert corresponding to the web section of the insert. The transverse part of the further slot is provided for engaging with outwardly extending projection 96 of plate 94.

When subassembly 86 is in a lowered position projection 96 is received within the further slot to hold the polystyrene block in position on the end of the insert with sufficient force to resist displacement when the AAC mixture is introduced into the mold. When the AAC block is in the green state of cure, subassembly 86 is raised thereby withdrawing projection 96 from the further transverse slot to allow removal of the polystyrene block from the mold by lifting the polystyrene block off end 44 of insert 40.

Manufacture of panel 10 will now be described with particular reference to Figures 8 to 18. In one form, a mold, generally denoted as 60, is provided within which a block can be molded from which a multitude of panels 10 can be produced. Mold 60 includes base 62, a first side wall 64, a second side wall 66, a first end wall 68, and a second end wall 70. It is to be noted the second side wall 66 and second end wall 70 are omitted from Figures 13 and 14 for clarity. Mold 60 is not provided with a closed top or lid but rather is open. Typically, mold 60 is in the form of an open box having dimensions corresponding to the length and width of panels 10, but not corresponding to the thickness of the panels since a block in the form of a pre-form for the panels is formed first, followed by slicing or cutting of the block into separate individual multiple panels being formed in a single molding operation comprising a number of different workstations.

Two lower formers 72 are located at spaced apart locations on base 62 to provide support for channel section inserts 40 when placed in a substantially vertical orientation within mold 60 to form the lifting element. Formers 72 have a size, shape, profile and cross-section corresponding to the size, shape and profile of access voids 52. Formers 72 can be located at any suitable location within mold 60 depending upon the required position of the inserts. Formers 72 are provided with U-shaped grooves 73 or cut-outs corresponding in shape, size and profile to the cross-section of inserts 40 so that the respective one ends 44 of inserts 40 can be received therein to securely retain inserts 40 in place prior to and during manufacture of panel 10. In one form, side walls 64, 66, in the form of side shields, are each provided with two slots 65 located at spaced apart locations at the upper edge in use of each wall for locating upper formers as will be described later. However, in other forms, slots 65 can be omitted entirely and replaced with clips or similar fittings for locating the upper formers, particularly to provide flexibility in locating the inserts.

A reinforcement mesh 74, in the form of a generally planar sheet of mesh or similar, or a cage having a double layer of mesh in the form of two interconnected sheets of mesh is used to reinforce the panel. One form of mesh 74 comprises a multitude of lengthwise extending reinforcing rods 76 and a multitude of transversely extending reinforcing rods 78 interconnected in a grid or generally interconnected regular array is located within mold 60 to rest above base 62 and above lower formers 72 so as to provide a clearance between base 62 and the lowest part of mesh 74. It is to be noted that the number of sheets of mesh or cages of mesh located in mold 60 corresponds to the number of panels being made from a single molding operation in mold 60. Accordingly the required number of sheets of substantially planar sheets of mesh 74, are located in spaced apart substantially parallel relationship inside mold 60 as shown more particularly in Figure 14. Similarly, if cages are used as the reinforcement for each individual panel, the cages are located in spaced apart substantially parallel relationship to each other inside the mold.

In one form, a sheet of suitable material, such as a membrane is located between the lower surface of lower former 72 and base 62 of mold 60 to seal around former 72 to prevent the AAC mixture from gaining access internally within former 72, such as for example, by flowing around and underneath former 72. However, in other forms, the underside of the former can be manufactured from a suitable material to seal the underside of the former to the base of the mold thereby doing away with the need to have a separate membrane.

Inserts 40 are then located in place in grooves 73 to extend substantially vertically so that selected longitudinal rods 76 are located within the spaces of hooks 46 of insert 40 by tips 48 of the respective hooks 46 being forced open to allow movement of tips 48 of hooks 46 past rods 76 as shown in Figures 12a, 12b and 12c, to clip the insert to the selected rods collectively so as to retain inserts 40 in the substantially vertical orientation. It is to be noted that in one form, insert 40 has four spaced apart hooks 46 in which three hooks are located at or towards one end, being the lower end in use, when in the mold, and a single hook located at or towards the other end, being the upper end in use, when the inserts are in the vertical orientation. After rod 76 passes tip 48 of hook 46, tip 48 is free to partially close by moving to resume the at rest position, thereby trapping rod 76 in the space between shank 41 of hook 46 and web 42 of insert 40. When all of inserts 40 are secured in place within mold 60 and retained by hooks 46 engaging mesh rods 76 and being retained in grooves 43 of the pair of lower formers 72, one or more upper formers 80 are placed over the upper ends of inserts 40 collectively so as to sandwich each insert 40 between an upper former and lower former. Two upper formers 80 are generally used in alignment with the respective lower formers 72. In one form, upper former 80 is of a generally trapezoidal prism shape having a support pin 82 extending outwardly from each end and a multitude of U-shaped slots or grooves 84 located at spaced apart locations in the lengthwise extending direction. The position of grooves 84 correspond to the position of inserts 40. Support pins 82 are received in slots 65 of both side walls 64, 66 to assist in locating upper former 80 in place. The shape and/or profile of upper former 80, corresponds to the shape and/or profile of access voids 52 located at spaced apart intervals along one longitudinal side of panel 10. Thus, lower formers 72 and upper formers 80 are of substantially the same profile and size. The shape of slots or grooves 84 correspond to the profile of inserts 40 so as to be received therein.

In one form, (not shown), upper former 80 is releasably secured to the upper edge of side walls 64, 66 by a suitable fastener, such as for example, a clip, pin or similar to temporarily connect the ends of the upper former to the top of the side walls. This arrangement provides improved flexibility in locating the upper formers in the mold. In this form, slots 65 can be omitted.

When upper formers 80 are located in place with pins 82 received in slots 65 all of the inserts 40 are collectively sandwiched between lower formers 72 and upper formers 80 so as to be securely retained in place both prior to and during formation of panel 10. Alternatively, upper former 80 can be replaced by a multitude of separate polystyrene blocks which are placed over the upper ends of each insert 40 and retained in place by an overhead gantry comprising plates 94 with projections 96 located at spaced apart locations corresponding to the spacing apart of the ends of inserts 40. Subassembly 86 is lowered to an extent that projections 96 are aligned immediately above each polystyrene block with projection 96 in register with the further transverse groove of the polystyrene block fitted over the end of the insert. Subassembly 86 is further lowered so that projection 96 is received in the further transverse slot to retain the polystyrene block in position at the upper ends of each insert. In this position the inserts are sandwiched between lower formers 72 and the upper formers in the form of the polystyrene blocks which are retained in position by plates 94 depending downwardly from the framework of subassembly 86 to retain each insert in the correct position and orientation.

A suitable fluid mixture for forming the AAC panels is introduced into mold 60 by a suitable delivery system to fill the chamber formed in mold 60. One form of delivery system is pneumatically or hydraulically conveying the fluid mixture. Other forms include a mechanical pump or the like. The fluid mixture flows over and around lower formers 72, mesh 74, inserts 40, and due to the composition of the mixture, expands upwardly to flow up to and over upper formers 80 to completely fill the internal chamber of mold 60. It is to be noted that the profile of formers 72, 80 correspond to the shape of access voids 52 by each having a pair of tapering sides flanking a central straight section.

After molding, walls 64, 66, 68, 70 are displaced from mold 60 to reveal a block of aerated concrete mix remaining in the mold chamber. Upper formers 80 and lower formers 72 are removed from the AAC block which is then cut longitudinally into separate panels 10 between the various sheets of mesh, such as for example, using a wire cutter or similar. Thereafter, each panel now of a nominal thickness

corresponding to the thickness of the finished panel, is allowed to cure, such as by air drying and then autoclaved to form a rigid panel of AAC having the desired shape and dimensions with ends 44 of inserts 40 exposed in access voids 52. Optionally, the panels are trimmed to exact size. It is to be noted that the inserts do not extend beyond the width of the panels so that the long side of the panels can be trimmed without interference from the ends of the inserts. The fully cured panels are then stacked with ends 44 in approximate, if not close, alignment with each other ready for packaging, as shown in Figure 18. After packaging, the stack of panels in alignment with each other is stored awaiting distribution when required.

After transportation and unpacking at a construction site, the panels can be lifted simultaneously while remaining in stacked relationship by the movable grip or pin of a suitable lifting device engaging apertures 50 of the lifting elements of the lower most panel. Further, it is to be noted that in one form of the lifting device, all of the panels are engaged by the lifting device to lift and transport the panels by engaging the sides of the panels to prevent lateral movement of any one of the panels so that all panels are locked in place. The described arrangement has been advanced by explanation and many

modifications may be made without departing from the spirit and scope of the invention which includes every novel feature and novel combination of features herein disclosed.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1 . A method of making a building panel having at least one lifting element, the panel having a body portion generally in the shape of the panel, and the body portion having at least a first surface associated with the lifting element, the method comprising the steps of providing a mold generally for forming the shape of the body of the panel, locating the lifting element at a predetermined location and at a preselected orientation within the mould, the lifting element having a first part and a second part, securing the first part of the lifting element within the mold to maintain the predetermined position and orientation of the lifting element during formation of the panel, forming the body of the panel generally in accordance with the shape of the mold, wherein the position and orientation of the lifting element is such that the first part of the lifting element is secured to the body and the second part of the lifting element is accessible from outside the first surface of the body, the second part of the lifting element provided with an engager for selective cooperative engagement with a lifting device to facilitate lifting of the panel.

2. A building panel comprising a body portion generally in the shape of the

building panel, the building panel having at least a first surface, the first surface being associated with at least a first lifting element for use in lifting the building panel, the lifting element having a first part for secure attachment of the lifting element to the body of the building panel in the region of the first surface to fixedly locate the lifting element with respect to the panel to facilitate lifting of the panel, the lifting element having a second part accessible from outside of the first surface of the building panel for cooperation with an external lifting device to lift the panel using the lifting device, wherein the second part of the at least first lifting element is provided with an engager for selective cooperative engagement with the lifting device such that when the lifting device is connected to the engager of the first lifting element, the panel moves in response to corresponding movement of the lifting device to move the panel. 3. A method of making a building panel according to any preceding claim

comprising in which the mold is a disassemblable mold having a base, preferably located upon or connected to a movable assembly or carriage for transporting the mold from one location to another location. A method of making a building panel according to any preceding claim in which the mold is a box-like structure provided with removable sides or is collapsible.

A method of making a building panel according to any preceding claim in which the mold has a lower former, preferably a pair of spaced apart substantially parallel lower formers, located at or near to the ends of the mold.

A method of making a building panel according to any preceding claim in which the lower former is provided with at least one receiver for receiving the end of the lifting element for locating and orienting the lifting element during manufacture of the building panel, wherein the shape or profile of the receiver corresponds to the shape or profile of the end of the lifting element so that the end of the lifting element is received within the receiver.

A method of making the building panel according to any preceding claim in which the lower former is of a generally trapezoidal prism shape having a base or lower surface of greater dimensions than the top or upper surface.

A method of making a building panel according to any preceding claim in which the lower member is at least partially hollow, being provided with cavities, chambers, openings, voids or similar located internally within the lower former.

A method of making the building panel according to any preceding claim in which the sidewalls of the mold support an upper former for forming access voids along one longitudinal side of the building panel in which the support of the side walls include notches, grooves, cut-outs, voids, channels, rebates, slots or similar located in, at or along the upper edge of the sidewalk

A method of making a building panel according to any preceding claim in which the support is a single member or element extending from one side of the mold to the other side of the mold.

A method of making a building panel according to any preceding claim in which the support includes two separate supports, one extending from each side of the upper former, the two supports in the form of pins being collinearly aligned with each other to extend on opposite sides of the upper former. 12. A method of making a building panel according to any preceding claim in which the lifting element is provided with retainers located at spaced apart locations along the length of the lifting element for retaining the reinforcement in position during manufacture of the building panel.

A method of making a building panel according to any preceding claim in which the retainers cooperatively engage with reinforcing elements forming the reinforcement wherein the retainers are spaced apart from one another in accordance with the spacing apart of the reinforcing elements.

A method of making a building panel according to any preceding claim wherein the retainers each have a shank portion and a tip portion, wherein the tip portion is resiliently biased towards a closed position for cooperatively engaging the reinforcing elements.

A method of making a building panel according to any preceding claim in which the former is provided with at least one receiver for receiving an end of the lifting element, wherein the receiver is of a shape and profile corresponding to the shape or profile of the lifting element.

A method of making a building panel according to any preceding claim in which the receiver is a slot, cut out, rebate, groove, channel, section or similar for receiving and retaining the end of the lifting element.

A method of making a building panel according to any preceding claim in which the walls of the mold are provided with a slot or notch for receiving part of the upper former, wherein the slot or notch has a rectilinear profile.

A method of making a building panel according to any preceding claim in which the upper former includes a planar member, the planar member being movable, wherein one side of the upper former cooperatively engages with the planar member by the planar member being flexibly inserted into the receiver and another side of the upper former cooperatively engaging with the end of the lifting member.

A method of making a building panel according to any preceding claim in which movement of the planar member in the direction towards the lifting element holds the lifting element in the correct position and orientation during manufacture of the building panel.

20. A method of making a building panel according to any preceding claim in which the planar member is a plate provided with a projection in which the projection is received within the receiver of the upper former.

21 . A method of making a building panel according to any preceding claim in which the movable planar member is a hinged or suspended plate downwardly depending from a framework member, wherein movement of the planar member with respect to the framework member aligns the plate with the receiver of the upper former.

22. A method of making a building panel according to any preceding claim in which the mold further comprises a membrane located intermediate lower surfaces of the lower former and the upper surface of a base of the mold to provide a seal between the lower former and the base of the mold.

23. A method of making a building panel according to any preceding claim in which the upper former is one or more polystyrene blocks having a profile

corresponding to the profile of the access void in which one surface of the polystyrene block has one receiver for cooperatively engaging with the plate and another surface of the polystyrene block is provided with a further receiver for cooperatively engaging with the end of the lifting element.

24. A method of making a building panel having at least one lifting element, the panel having a body portion generally in the shape of the panel, and the body portion having at least a first surface associated with the lifting element substantially as herein described with reference to the accompanying drawings.

25. A building panel substantially as herein described with reference to the

accompanying drawings.