CAST PANELS

Technical Field

The present invention relates to the manufacture of precast panels employed in buildings, and more particularly but not exclusively to low rise buildings.

Background of the Invention

Methods and apparatus employed to cast panels to form the sides of buildings, are generally labour intensive and are not adapted to easily cast the panels with a window or door aperture. Still further, the formwork employed is only designed to manufacture a single sized panel. Still further the decorative treatment of the panel faces are limited by the current methods of manufacture. Still further, the methods for prevention of water ingress from the external panel face to the internal panel face is inadequate or subject to poor on site work practices. Still further, the methods of sealing openings in panels for doors or windows are limited by the life of the sealants used.

Object of the Invention

It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.

Summary of the Invention

There is disclosed herein a method of manufacturing a cast panel, said method including the steps of: providing a plurality of generally coextensive reinforcing tendons; providing and positioning on the tendons, at least two first form members, which members extend generally transverse of the tendons, with the tendons passing therethrough, the members being spaced longitudinally along the tendons; providing at least two second form members, which second form members extend between the first four members so that the first and second form members cooperate to surround a volume to receive a material to be cast to form the panel; and tensioning the tendons before said material sets to form the panel. There is disclosed herein an assembly to cast a panel, said assembly comprising:

a generally horizontally extending bed providing a generally upwardly facing surface; a plurality of horizontally extending members generally abutting said surface and cooperating to generally surround a space to receive material to form the panel; 5 tendon support members adapted to receive and support a plurality of tendons so that the tendons are generally horizontally oriented and pass through said space; and wherein at least two of the space enclosing members are positioned to extend across the tendons so that the tendons pass therethrough.

Brief Description of the Drawings ι o A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein:

Figure 1 is a schematic top plan view of an assembly within which a concrete panel is to be cast;

Figure 2 is a schematic top plan view of a plurality of "bank" assemblies within 15 which cast panels are to be formed;

Figure 3 is a schematic sectioned side elevation through one of the assemblies of Figure 2;

Figure 4 is a schematic sectioned side elevation of a panel formed in one of the assemblies of Figures 1 and 2; 20 Figure 5 is a schematic sectioned side elevation of a further panel being cast in one of the assemblies of Figures 1 and 2;

Figure 6 is a schematic side elevation of a tie employed in the assemblies of Figures 1 and 2;

Figure 7 is a schematic end elevation of a collet employed in the tie of Figure 6; ₂ 5 Figure 8 is a schematic sectioned end elevation of a portion of the assembly of

Figures 1 or 2;

Figure 9 is a schematic side elevation of one of the assemblies of Figure 2 showing the components in more detail;

Figure 10 is a schematic top plan view of Figure 2 showing the individual components in more detail;

Figure 11 is a schematic sectioned side view of Figure 2 showing the individual components in more detail; Figure 12 is a schematic side elevation of the end form through which the tendons pass;

Figure 13 is a schematic side elevation of the end form to the aperture in Figures 10, 1 or 2;

Figure 14 is a schematic plan view of a stretcher bond pattern jig for holding 10mm thick brick wafers for embedding in panel 21;

Figure 15 is a schematic section view of Figure 14 showing how the cam grips the brick wafers against a finger stop;

Figure 16 is a schematic overhead view of a travelling spray rig for final waterproof finish; Figure 17 is a schematic end view of the overlapping spray pattern of Figure 16;

Figure 18 is a schematic section end elevation showing window and door frame sealing;

Figure 19 is a schematic side elevation of a casting bed to be employed in the casting of concrete panels; Figure 20 is a schematic end elevation of the bed of Figure 19;

Figure 21 is a schematic side elevation of a stack of casting beds; and Figure 22 is a schematic top plan view of the casting bed of Figure 19.

Description of the Preferred Embodiment

In the accompanying drawings there is schematically depicted an assembly 20 within which there is cast a panel 21 , the panel 21 being adapted to provide a wall of a building, particularly a low rise building. The panel 21 may be cast to have one or more window or door apertures, or other apertures required for the delivery of services to the building.

A plurality of assemblies 20 may be "banked" as best seen in Figure 2 so that a plurality of panels may be cast.

A fixed structure 22 is provided and to which there is fixed a plurality of tendons 23. The tendons 23 then extend to a plate or beam 24 to which a force can be applied to tension the tendons 23. Positioned on the tendons 23 are transverse first form members 25, arranged so as to extend generally transverse of the tendons 23, with the members 25 having apertures through which the tendons 23 pass. The aperture form members 26 also have the tendons 23 passing through them, which members 26 cooperate to enclose an area to provide an aperture in the panel 21. In Figure 1 the aperture is intended to be a window. However, other apertures may be cast, with those apertures being adapted to provide door openings or other service opening.

Figure 12 shows a schematic side view of first form member 25 showing the apertures for the passage of tendons 23.

Second form members 27 extend generally parallel to the tendons 23 and extend between the first form members 25 to enclose a space within which the panel 21 is cast. The second form members are supported in position by means of ties 28 which may be attached to the tendons 23 if required. The ties 28 include deformed reinforcing rod 29, or other material, to which there is fixed by crimping or welding, collets 30. The collets 30 have a threaded passage 31 which faces an aligned aperture in the second form member 27 to thereby permit a bolt 32 to pass through the second form members 27 to thereby engage within the passages 31. The head 33 of each bolt 32 abuts the outside surface of the associated second form member 27 to hold it in position and support the tendons 23. The second form members 27 may be shaped to give them the required stiffness and enable them to be formed from relatively thin section. Attached to the ties 28 are form members 34 and metal form 18 which cooperate with the form members 26 to provide the door or window aperture. This is shown in Fieures 10 and 11.

The panel spacer 19 has apertures for the passage of the tendons 23 and is the first member placed, transverse to the tendons 23. The detail of panel spacer 19 is shown in Figures 9, 10 and 11.

The first form member 25 is placed abutting the spacer 19 and second form members 27 are placed in position and are connected to each other and ties 28 by bolts 32. The closing second form member 25 is placed in position abutting a second panel spacer 19 to enclose a casting space for panel 20. The process is continued with the first form member 25 and the second form member 27 cooperating to create each panel with the panel spacer 19 being the first and last member placed and creating a separation between each panel where the tendons 23 will be cut when the concrete is cured and the tension has been removed from plate 24.

When the various form members are placed in position, the tendons 23 are tensioned thereby supporting the form members 25 in the desired configuration. Thereafter, concrete is delivered to the various spaces within which the panels are to be cast.

Preferably, the panels 21 are cast by first delivering to the casting space, a concrete layer 35 comprising a cement rich fine aggregate. A further layer 38 is also formed of such material to give a good finish to both faces of the panel. The intermediate layer can be formed of a coarser, larger aggregate and less cement mixture.

The lower face of the panel in contact with the casting bed is finished with a smooth finish for internal walls.

The upper face of the panel is the external face and is stamped with a decorative finish or using a mould as shown schematically in cross section in Figure 5, having a raised detail. Also by having a closed mould attached to the panel spacer 19 and second form member 27, using pressure grouting to fill the void, creating a relief casting on the surface of the panel.

Alternatively by using the jig detailed in Figures 14 and 15 wafers of brick, or other material, are loaded into the jig, the jig is inverted and positioned where desired

on the panel 21. The holding cam is released allowing the brick wafers to settle on the surface of panel 21. The bricks are then forced into contact with the panel surface to bonding the bricks to the panel. A brick skin is applied to the panel.

When all decorative treatment of the external face is complete, a waterproof coating is applied to the external face of the "banked" panels 20 as shown in Figure 2, by using spray guns travelling the length of the casting bed at a fixed height and with an overlapping spray pattern as detailed in Figures 16 and 17. This coating can be clear or coloured.

By using the section of moulding shown in Figure 18 a waterproof seal is created at all apertures in the panel 21.

In each panel 21 that is cast, the collets 30 extend to the edge of the panel 21 providing a threaded passage 31 to receive fasteners to enable lifting of the panel 21.

The threaded passages are used to aid the construction of buildings formed from the panels 20. Additional reinforcement can be added to the panels if required. In Figures 19 to 22 there is schematically depicted a casting bed 50 which may be employed to perform the method of forming the previously discussed panel 21. In this embodiment the casting bed 50 includes a base frame 51 consisting of a generally planar and horizontal base 52 supported by legs 53. Extending between the legs 53 are rods 54 to aid in retaining the legs 53 in the correct position. More particularly, the rods 54 would be tensioned to ameliorate any problems associated with the base 52 sagging.

The base 52 would be adapted to receive an assembly, such as the assembly 20 described with reference to Figures 1 to 18. However, the bed 50 would include end members 55 positioned directly above the legs 53 and between which the tendons 23 would pass. The end members 55 also provide a mounting for the next adjacent above bed 50 of the stack 56. The stack 56 is a stack of beds 50. As can be noted the legs 53 rest on the end members 55 of the next below bed 50.

Each bed would be provided with a series of eyelets 57 to enable the bed 53 to be lifted by a crane or other hoist device.

UBSTITUTE SHEET (RULE 26)

By employing the bed 50 and having it adapted to be stacked, a series of panels can be simultaneously cast and/or curing.