A PANEL MOLDING APPARATUS AND METHOD OF MANUFACTURE

This invention relates to a panel molding apparatus, a method of manufacture, and product resulting from use of the apparatus and pursuant to the method.

BACKGROUND OF THE INVENTION

In one conventional method of construction of inner walls for buildings, these are made by providing a structural frame and then attaching cladding in the form of external sheets of material to respective sides of the frame.

A typical base frame will be constructed from either wood or metal and will have sheets of appropriate material, such as that material sold under the trade mark "GYPROCK", which is then finished by appropriate treatment to provide a flush external surface.

Such a system is now widely used but requires tailored construction on site at least for most installations.

This technique has inherent costs because of the multiplicity of materials that are required to be brought together and used, by reason of the need for expert trades to construct and finish, and subsequently has limited potential for providing both sound and heat insulation from one side to another.

PROBLEM TO WHICH THIS INVENTION IS DIRECTED

The challenge is to provide some material or construction method which would at the least provide some potentially reduced costs in achieving a final inner wall which at the same time can adequately perform the function needed.

BRIEF SUMMARY OF THE INVENTION

Our concept is to provide for a wall that can be constructed from a plurality of individual panels, each of which can be constructed according to mass construction techniques.

In preference, the panels are each of a consistent height so that they might extend

typically from a floor to a ceiling and be able to be abutted side to side thereby providing a completed wall made up of a plurality of these panels.

A panel of this type, is in preference, a long panel which has an appropriate width to match preferred modular units of distance, and which therefore can be said to be modular units so that a single set number side by side would match an appropriate width of a wall as might traditionally be required.

A problem with this arrangement however is to be able to manufacture economically, a panel that can perform this function.

My proposal is to effect a manufacture of such a panel by using a mold in which a panel performing this function can be cast as a single integral unit and which can include a core having at least one hollow passageway extending along its length.

In one form then, the invention can be said to reside in a method of manufacture of a building panel where the panel is cast in a mold as a single integral article, the panel being of elongate dimensions having a shape and size in cross section along its direction of elongation that is consistently the same along the length of the panel, at least one hollow core passing fully through the panel from a one end of the elongate shape of the panel to an opposite end of the elongate shape of the panel, the mold having molding surfaces providing for and defining outer surfaces of an outer side of the panel and the core or cores through the panel, the molding surfaces for the panel surfaces which are not defining either end of the panel being arranged to be movable in each case between a molding position, and a retracted release position where the molding surfaces are retracted from the molding position to an extent that facilitate extraction of the panel by effort along the direction of elongation of the panel relative to the mold, the method including the steps of positioning the molding surfaces in a molding position, effecting a filling of the mold with a settable material, then subsequent to a sufficient setting of the cast material, retracting the molding surfaces which are not defining either end of the panel to a release position, then effecting an extraction of the formed panel from the mold by effecting effort on the panel relative to the mold in an elongate direction of the panel.

In a further form, the invention can be said to reside in a method of manufacture of a building panel further characterised in that movement between of the molding surfaces from the retracted position to the molding position and from a molding

position to a retracted position is effected by respectively increasing in the first case and decreasing in the second case decreasing fluid pressure within an expandable and retractable chamber or chambers positioned to effect relative movement between a body of the mold and the respective molding surfaces which are not defining either end of the panel.

In preference, the material from which such a panel can be cast should be a traditional building material such as plaster and in preference this should be reinforced with appropriate reinforcement.

In order for this to be an economic manufacturing technique, options have been sought and it has been discovered that such a panel can be manufactured by using a mold in which a panel can be cast as a single unit and in which there are one or more cores and in relation to the mold, and a surface defining an outer surface of a panel to be molded which includes at least in the main a member or members which can be positioned in a casting position and which subsequent to having a panel cast, can be released or retracted to a release position, and that a core includes an outer surface that can be maintained in a first casting position and subsequently retracted into a release position so that when the respective surfaces are all in the relaxed or release position, the cast panel can be extracted by movement of the panel along its direction of elongation.

In preference, the means to effect a change in the status of the respective surfaces are adapted to be responsive to an increase or decrease of fluid pressure in a chamber or chambers.

In preference, the fluid is gaseous pressure and the chambers are deformable in response to such changes in pressure.

In preference, the surfaces defining at least in part the molding surface defining an outer face of the panel to be cast are each provided by a sheet of resiliently stretchable material.

In preference, the resiliently stretchable material is selected from plastics material including polyurethanes.

In preference, a core which extends along within the mold includes an outer jacket and a central member or members, and positioned therebetween, a plurality of

deformable chambers which in a retracted position are adapted to effect a retraction of the outer jacket and in an expanded position are adapted to effect an expansion of the outer jacket into a molding or casting position.

One of the difficulties with a mold for this purpose is that there can be a potential build up of residual material on otherwise mated surfaces.

If two surfaces that are needed to be accurately spaced one with respect to the other have material that builds up on one or both of the surfaces then this spacing can be different and the size of the product cast can then be different.

This in many cases is a serious difficulty and may mean regular stripping of the mold and cleaning of any surfaces. This can be costly and time consuming.

Our answer in preference in this case is to arrange that the mold has an outer surface defined by members which provide a water sealed volume for the mold when in a molding status (the exception is air holes that are designed to allow for air passage there through but restrict plaster particles). This has the result then of ensuring that surfaces that are used to define the dimensions of the molded product are kept sealed and are accordingly kept clean from incidental contamination during the molding process. When the mold is expanded the product is then cast with the plaster if plaster is being used being solidified and therefore we can expect negligible contamination will occur of the then vulnerable surfaces.

In a further form of this invention, it can be said to reside in a method of manufacture of a building panel which includes use of an apparatus as characterised above and wherein there is first provided the step of effecting positioning of the respective surfaces into a molding position within the mold, causing an introduction into the molding surfaces of previously wet mixed plaster, allowing the plaster to set, effecting a change in position of the respective molding surfaces so that these are changed into a release position, and then effecting by pressure or tension from one or other ends of the panel or both ends, a withdrawal of the panel lengthwise from the mold.

One of the aspects of the invention relates to the fact that in the way described, a single integral unit can be manufactured which either limits or removes the need for a level of expertise on site which could be costly.

By use of the method and/or the apparatus, panels thus far have been able to be manufactured economically with widths that are appropriate in modular terms and these might be for instance 600 mms in width, and 120 mms in depth and any reasonable height typically 2400 mms or more which can be in fact selected and can be varied from time to time by use of the same mold.

In accordance with this, there is provided with respect to the mold, an end plate the position of which can be adjusted to be at any selected position in from an end of the mold and therefore also from an end of the core or cores of the mold.

Provided the inlet for plaster introduction into the molding space is accessible, then an end plate can be positioned at a selected position along the length of the mold and can be maintained in such position either by reason of its fitted dimensions or by reason that once located the change in status from a release position to a molding position of the molding surfaces will inherently then also lock in the position of an end plate.

An advantage of this then is that with a mold of this type one or more panels can be manufactured according to a selected height so that these can then, once manufactured, be conveyed to a site and be constructed without need for further expertise at a tradesman's level.

In preference, it is of advantage that each panel have a side shape that will allow for a matching interlocking along its full length (this would be height when in a constructed position).

In preference, the material to be used would be the conventional plaster and this is typically plaster of Paris, but other conventional building materials that can be cast could be considered.

Description of the drawings

For a better understanding of this invention it will now be described with the assistance of drawings in relation to a preferred embodiment, wherein:

Figure 1 is a perspective view of a mold according to the embodiment;

Figure 2 is a perspective view from an opposite position of the same

embodiment of the mold;

Figure 3 is a cross sectional view along the lines 3-3 as shown in Figure 4;

Figure 4 is a top view looking in plane at the mold;

Figure 5 is a cross sectional view through the middle of a mold and is showing an end plate in a furthermost end position;

Figure 6 is the same view as in Figure 5 except that the end plate is now shifted inwardly to provide a mold for a panel of a lesser length;

Figure 7 is the same cross sectional view as in Figures 5 and 6 but now illustrates the next stage in the molding process in which the respective surfaces are caused to be urged into the molding position;

Figure 8 illustrates the introduction now of wet plaster and air holes in an end plate to allow for air from a molding space to be exhausted to atmosphere;

Figure 9 illustrates a conclusion of the step of introduction of the plaster;

Figure 10 illustrates a retraction of the respective molding surfaces;

Figure 11 illustrates the step of removal of the cast panel;

Figure 13 is a cross sectional view of a one of the cores in a panel release position;

Figure 14 is the same cross sectional view as in Figure 13 of a core and showing the mold now in a molding position which is an expanded position;

Figure 15 is a cross sectional view of the whole of the mold illustrating the respective molding surfaces being in a retracted or mold release position;

Figure 15a is an enlarged view of a top part of the view in Figure 15;

Figure 15b is and enlarged view of a bottom part of the view in Figure 15;

Figure 16 illustrates the same cross sectional view as in Figure 15 except in this

case the molding surfaces are in the molding position and there is shown in cross section a panel which has been cast within the panel molding space;

Figure 16a is an enlarged view of a bottom part of the view in Figure 16;

Figure 16b is and enlarged view of a top part of the view in Figure 16;

Figure 17 is an end view of a panel according to the embodiment as manufactured by the apparatus;

Figure 18 is a perspective view of a panel as in Figure 17;

Figure 19 is a side view of the same panel; and

Figure 20 is a cross sectional view of the panel along the lines 20-20 in Figure 19.

Detailed description of the embodiment

Now referring to the drawings in detail, the mold 1 is made up of a body 2 which includes a plurality of reinforcement strengthening webs 3.

The shape of the body is such that there will be provided therein, a long and relatively narrow molding space 8a which also has running through it in this case two cores 4 and 5.

These cores 4 and 5 are supported by being secured at one end to a first end plate 6, and are to some extent maintained in their otherwise cantilevered position by reason of a movable end plate 7 (coated in a harder urethane plastics material) oppositely positioned with respect to the first end plate 6, which also provides a movable end closure to the molding space 8a. There is a further end plate 7c coated in this case with a plastic coating of harder urethane plastic, which in a molding position will lie against the first end plate 6, and when the molded product is to be removed is engageable by a push rod 7b through aperture 7e to effect engagement of the plate 7c, and hence effect engagement against this to effect removal of a molded product. The advantage of the additional plastic coating is to avoid a like metal to metal contact as the respective plates are moved along the mould 1.

There is an inlet valve 8 at one end for mixed plaster, which is forced in at pressure into the molding space 8a and there is an air outlet 8b in an upper part of the end plate 7 which is arranged to release air but to restrict passage therepast of plaster by reason of its sieve size.

For an effective molding to take place, there is a technique for being able to extract a resultant product and to this extent then, firstly the cores and we will take core 4 as typical , has an inner support structure shown at 10, and outer resilient tube 11 which acts as a jacket around the inner support structure 10. Positioned between these respective members, namely the tube 1 1 and the support structure 10, there are a series of chambers 12, which in one form are of approximately elliptical shape in cross section. When caused to be filled with a fluid at higher pressure, these will be caused to assume a larger volume shape which has the result of expanding the outer surface of tube 11 to then be in a molding position as shown in Figure 14.

This outer tube 11 , is in this case, formed from a polyurethane plastics material and can therefore provide both a degree of resiliency and flexibility, and is also a surface that can assist in effecting a release surface to surface from a cast plaster surface.

There are means which are not shown specifically, which couple together each of the chambers to a common air supply such, that by increasing the pressure the effect can be to be to expand each of the chambers and hence the outer jacket 11 and by either releasing the pressure so that the natural resiliency will return to the retracted position as shown in Figure 13, or in another case actually physically withdrawing and having a negative pressure within the chambers also achieving the same result.

Referring now specifically to the steps shown in Figures 5 through 11 , in Figure 5 the molding positions are generally in the start position, with the molding surfaces in a first instance the cores at 4 and 5 being in a retracted position, and the sides being in a relaxed or retracted position and an end plate 7 being in its most extended position.

A positioning rod 7a is then used to locate the end plate 7 in an appropriate position as shown in Figure 6, and the next action then is to effect an expansion of the molding surfaces both for the outer surfaces and the core surfaces which also

then lock the end plate 7 into position.

Mixed plaster is then injected through entry 8 into the molding area 8a, and in order to allow for removal of air, the air vent in the vicinity of 8b allows for this but will stop any passage therepast of the wet plaster.

Once this action is completed, the mold is then left for a sufficient period for the plaster to set and this stage is shown at Figure 9.

The molding surfaces, including those of the cores 4 and 5, are then released and/or retracted as is shown in Figure 10, and there is then a push rod 7b which is used to be inserted from one end to push a further plate 7c, which bears against the now cast product 7d so that this is extracted out of the end of the mold 1.

The collective arrangement is now further shown in Figures 15 and 16.

Figure 15 illustrates the mold 1 in a released position.

To this extent then, there are expandable and contractable resilient tubes as shown at 13, 14, 15 and 16 which cause side members 17 in the one case and 18 in the other to either be pushed inwardly or as shown in Figure 15 allowed to move outwardly and therefore into a release position.

Resilient sheets, 19 on one side and 19a on the other, are formed from a urethane plastics material so as to provide an appropriate surface to effect an easy release between cast plaster and the surface of the plastics material and also be stretchable.

Accordingly, there is a tapered ramp at each quadrant for instance provided by rails 20, 21 , 22 and 23 each of which are secured to respectively an upper or lower part of the sheets 19 and 19a which are caused by reason of their engagement with a matching sloping surface as shown in 24, 25, 26 and 27 to allow the respective sheets 19 and 19a to which they are attached to be relaxed but specifically as shown in Figure 16,16a and 16b, when in the molding position.

Each of these rails 20 through 23 interengage in the case of 20 and 21 a bottom member 27 and in the case of 22 and 23, a top member 28. This top member 28 is lifted by operation of each of the air lifts 9 which are operated synchronously to lift

the top member 28 when appropriate to allow for extraction of a molded product. This action also stretches the sheets 19 and 19a so that they will then be under tension during a molded product extraction. If they were not , it is considered they would then potentially snag an extracting molded product. Further the tension is useful to pull the top member 28

The bottom member 27 then in turn is secured at 29 and 30 with a bottom end of the plastic sheets 19 and 19a, and in like manner, the top member 28 interengages at 31 and 32 through the rails 20 through 23 with the ends respectively of the plastic sheets 19 and 19a.

Thus, as will be shown when compared as between Figures 15 and 16 (and accordingly 15a and b, and 16a and b), that as the air tubes 13 through 16 are filled, and the air lifts 9 have a reduced air lift pressure, there is a resultant lowering of the top member 28 under the formerly tensioned plastic sheets 19 and 19a., the effect then is to allow each sheet to release some former tension and further allow for coincident alignment of the rails 20, 21 , 22 and 23 with the corresponding shaped cavities, and this brings the parts into a molding status for the sheets 19 and 19a.

The mold 1 in this status has an inner molding surface defined by members which provide an essentially water sealed shape for the mold when in a molding status (the exception is the air holes that are designed to allow for air passage there through but restrict plaster particles and end areas where the possibility of slight changes in length may also not be so much of a problem). This has the result then of ensuring that surfaces that are used to define the dimensions of the molded product are kept sealed during an actual molding step and are accordingly kept clean from incidental contamination during filling of the mold and during the molding process. The product is then cast with plaster being solidified and therefore we expect negligible contamination of vulnerable surfaces.

As shown in Figure 16 there is then a cast material or in this case of course a panel 7d.

In Figure 17 we have the panel 7d, which is of the shape resulting from the mold as previously described, and this includes two passageways 36 and 37 in each case passing fully through the length of the panel and defining between outer planar sides 38 and 39 a body constructed of reinforced plaster cast in accordance with

the apparatus previously described.

The shape in this case is constant throughout its length and it is of the same size and has at each end in this case an interlocking shape at 40 in one case and 41 in the other.

This interlocking shape includes two repressed portions 42, and two matching projecting portions 43 at the opposite end, so that similar panels will then effect an interlocking effect which at least with sideway movement when the panels are held end to end will assist in their maintaining their relative positions.

The same panel 7d is shown in Figures 18, 19 and 20.

It will now be seen that the apparatus described is effective for providing a long and narrow panel which can be very useful in a building application, whether for an internal wall or for other applications.

The method of manufacture can now be discerned from the description of the apparatus where there is provided such an apparatus which is first caused to have at least most of its relevant positions defining the molding surfaces in a relaxed or retracted position. The next step is to set the end plate in an appropriate position so as to define for the purpose of its end use, the length of a panel and then effect of the surfaces effecting the molding shape.

By doing this, it will also lock in the end plate and the mold is then ready to be used for casting.

A plaster material, in this case plaster of Paris, mixed with an appropriate reinforcement fibre in water previously prepared, is injected into the mold and is then left until it is set.

The period will be selected as appropriate for the material used, the amount of water and the extent to which the degree of set will affect the extent to which it is self supporting.

There is also some advantage in the arrangement described insofar that there will be tolerance to some expansion or contraction of the material as it sets so that although, in most cases, a plaster can be selected that will have minimal expansion

or contraction, the arrangement will tolerant some variation of this.

Upon sufficient time being judged to allow for setting, the respective defining surfaces are relaxed or retracted and there is then effected an end pressure to push the thus cast panel endways from the mold.

The invention can also reside in the panel as a result of this method and also as a result of the use of the machine.