BACKGROUND ART Building panels have been proposed using a light-weight core material which can be clad in the factory or on a building site. The formation of such panels can involve complicated processes if manufacture is to be automated. In this specification, the term"core", though usually referring to an element which is clad by a skin or a coating, is not necessarily limited, and unless otherwise specified herein, is to be taken to encompass a panel formed from core-forming material which is not clad with a skin or coating.

The present invention aims to provide a method of and apparatus for forming a building panel core which is amenable to automation, or at least provides an alternative apparatus and method to that of the prior art. Other aims and advantages of the invention may become apparent from the following description.

DISCLOSURE OF THE INVENTION With the foregoing in view, the present invention in one aspect resides broadly in a method of forming a building panel core from a mixture having a core-filler portion mixed with a settable liquid to form a shapable, settable solid, the method including:

delivering the shapable solid to the upper face of a belt in substantially constant thickness thereacross; arranging the belt above a core forming mould such that the upper face is substantially coincident therewith; retracting the leading edge of the belt from the its position above the mould whereby the shapable solid falls from the upper face of the belt along the leading edge onto or into the mould; rolling the shapable solid to a desired configuration in the mould; and leaving the shapable solid in the mould for a time sufficient for the shapable solid to set.

In another aspect, the present invention resides broadly in a method of forming a building panel core from a mixture having a core-filler portion mixed with a settable liquid to form a shapable, settable solid, the method including: delivering the shapable solid to the upper face of a moving belt in substantially constant thickness thereacross; arranging the belt above a core forming mould such that the upper face is substantially coincident therewith; moving the mould beneath the belt at substantially the same speed as the upper face of the belt whereby the shapable solid falls from the upper face of the belt along the trailing edge onto or into the mould; rolling the shapable solid to a desired configuration in the mould; and leaving the shapable solid in the mould for a time sufficient for the shapable solid to set.

Preferably, the method is repeated in two stages so that a"double layer"core may be prepared. In such form, the method preferably includes providing a reinforcing sheet material on the upper face of the shapable solid, each stage being completed before the shapable solid has been allowed to set.

In delivering the shapable solid to the belt, it is preferred that the method include urging the shapable solid through an aperture having an upper edge substantially parallel to the upper face of the belt and vibrating the upper edge of the aperture. It is also preferred that the rolling of the shapable solid be performed by a roller, the method including oscillating the roller axially as it rolls the upper face of the shapable solid.

In another aspect, the present invention resides broadly in apparatus for forming a building panel core from a mixture having a core-filler portion mixed with a settable liquid to form a shapable solid, including: a belt having an upper face and delivery means arranged for movement relative thereto for delivering the shapable solid from the delivery means to the belt; a core forming mould arranged in operative association with the belt, the operative association being below the belt, and the mould and belt being arranged such that a leading edge of the belt may be retracted from the its disposition above the mould whilst the upper face of the belt remains substantially in register with the mould whereby the shapable solid may fall from the upper face of the belt along the leading edge onto or into the mould; and

rolling means operatively associated with the mould for rolling the shapable solid to a desired configuration in the mould.

Preferably, the belt and delivery means are duplicated, the second belt and delivery means being arranged in operative juxtaposition with the mould such that a second layer of shapable solid may be deposited atop the layer formed by the first belt and delivery means, whereby a second measure of shapable solid may fall from the upper face of the belt along the leading edge onto or into the upper face of the previous layer aready in the mould, the apparatus also including second rolling means operatively associated with the mould for rolling the shapable solid of the second layer to a desired configuration in similar fashion to the first layer. In such form, the apparatus further includes reinforcing sheet delivery means operatively associated with the mould for delivering reinforcing sheeting between the two layers of shapable solid whereby the finished core forming panel includes a reinforcing layer interposed between its faces in similar fashion to the panel described in our abovementioned co-pending patent application.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein: Fig. 1 is a diagrammatic plan view showing a plant layout for apparatus for forming a building panel core according to the invention; and Fig. 2 is a diagrammatic elevation view of the plant layout of Fig. 1.

DETAILED DESCRIPTION OF THE DRAWINGS The apparatus 10 for forming a building panel core shown in Figs. 1 and 2 indicates diagrammatically at 11 the stages of forming the core. A clean mould is delivered to the processing line 12 at the first station 51. At the second station 52, a layer of settable formable mixture is deposited onto a belt supported above the mould in a consistent layer in accordance with the relevant step of the method of the invention herein described. At the third station 53, the shapeable material is dropped from the belt onto the mould by retracting one end of the belt whilst leaving the upper face of the belt in register with the mould. At the fourth station the layer is rolled to form a layer of consistent depth and a substantially flat upper face.

At the fifth station, any excess material which may have accumulated at the sides of the panel during the rolling process is trimmed off. At the sixth station a layer of reinforcing mesh, textile or. other material is laid on top of the settable material. At the seventh station, a second layer of settable material is formed onto another belt. At the eighth station the second layer of settable material is dropped from the belt onto the top of the first layer (above the reinforcing) in the same fashion as in the case of the first belt. At the ninth station the second layer is rolled to give the panel a substantially flat upper face and at the tenth station, the panel is trimmed to provide the proper form of panel once set. At the eleventh and twelfth stations, further processing of the panel may be undertaken.

From the processing line, the mould with the formed or partly formed panel core undergoing the setting process is transferred to a holding line shown generally at 13. The moulds shown typically at 16 will have the panel core at various and progressive stages of setting and they generally progress in the

direction of arrows 17 firstly to the right as shown in the upper line of the holding line and then to the left in the lower line of the holding line. Along the back line 14, a pallet stacker 18 is provided to stack several moulds vertically as shown at 19.

As shown in Fig. 2 a turning station 21 is provided to turn the moulds in the stacks around to 90 degrees for destacking and demoulding at a demoulding station 23 once removed from the mould, the panels are stacked, preferably on pallets or the like, in vertical stacked relationship with one other and moved to a warehouse or the like. The moulds which have had a panel released are transferred to a wash station 27 along a mould conveyer 25 the panels are transferred to storage along a panel conveyer 29. From the wash station the moulds are elevated by an elevator 31 and transferred to the processing line along a clean mould conveyer 33.

In use, the panels are generally formed to be of a width of 800 millimetres and a length of 2 metres to provide for standard height panelling on a 100 millimetre standard module.

The thickness of the panels is preferably approximately 50 millimetres, each layer being 25 millimetres, although thicker or thinner panels may be formed. Although the panels are generally formed with substantially planar faces, it will be appreciated that other configurations may be formed. For example, textured-face panels may be produced, or panels may be shaped to mimic other building materials, such as, for example, concrete roofing tiles or corrugated sheeting for roofing or such like. In the case of such contoured panels, a mould of the appropriate contoured face is generally provided in negative form, and a substantially planar upper face is formed in accordance with the method of the invention so that the reinforcing and/or second or subsequent layers can be provided.

Modifications to the apparatus of the invention can be made to

accommodate the different forms of the panel, including, if desirable, the provision of panels having single, double, triple or more layers with or without reinforcing material between successive layers.

The embodiments described are for the purposes of illustration of one or more examples of the invention and it will be understood that any such modifications as would be apparent to persons skilled in the art are encompassed within the broad scope and ambit of the invention as herein set forth.