AU2018271273B1 - Method of Casting - Google Patents

Abstract

A bed of recyclable moulding casting medium is first laid down and then cut away to produce a mould for a concrete component or an element of other castable material. Once the mould has been used it is recycled for making further moulds. Various cutting devices such as milling bits, lasers and water jets allow the easy production of complex moulds previously not economically feasible for pre-cast concrete components. A large casting bed can be used to make multiple panels in a batch.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method of casting and is particularly suited for making concrete components.

BACKGROUND TO THE INVENTION [0002] The present invention is for a method of casting and whilst applicable to various materials will be discussed in the context of making concrete components. It is suitable for making a range of concrete components, such as beams, panels and culverts.

[0003] Precast concrete components have become a popular building option as they allow for relatively cheap and quick construction of a building or civil works compared with traditional techniques. It is particularly suited for adverse climates as it greatly reduces work time on site, often allowing construction at times of year when building activities are limited due to weather extremes.

[0004] Precast concrete components are traditionally made with the aid of formwork to hold the concrete in place until it cures. Rectangular shapes are readily achieved, however curved shapes prove difficult, requiring custom form work which is time consuming and consequently expensive to produce. Various factory systems have been developed to simplify the setup process, such as casting beds with movable shutters. These systems are usually restricted to making a single component at a time, often leaving the casting bed only partially utilised. In all known systems non-standard internal voids require customised form work leading to increased time and expense [0005] The object of this invention is to provide an improved method of making precast concrete components to alleviate the above problems, or at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION [0006] In a first aspect the invention provides a method of making castings, comprising the steps: a) filling a casting bed with a casting medium; b) cutting a casting mould into the casting medium; and c) filling the casting mould with castable material.

2018271273 27 Nov 2018 [0007] Preferably the method further comprises the step of recycling the casting medium, and preferably the casting medium is gypsum.

[0008] The method may include the further steps of dividing the casting bed into first and second regions using a separator, and filling the first region to a first depth with casting medium, and filling the second region to a second depth with casting medium.

[0009] Preferably the casting bed includes a step delineating a first area of a first depth and a second area of a second depth.

[0010] Preferably the casting material is concrete.

[0011] It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.

BRIEF DESCRIPTION OF THE DRAWINGS [0012] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows.

[0013] Figure 1 shows from above a system for making pre-cast concrete components according to the method of the invention.

[0014] Figure 2 shows a cross section of the casting bed of the system across the line 2-2 in Figure 1.

DRAWING COMPONENTS [0015] The drawings include the following integers.

concrete casting system casting bed walls casting medium hopper

2018271273 27 Nov 2018 movable cross members bed step shallow area deep area rails gantry tools

51-54 castings first region second region first depth second depth third depth excavated region excavated depth mould step mould slope

DETAILED DESCRIPTION OF THE INVENTION [0016] The following detailed description of the invention refers to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

[0017] The present invention is a general method of casting. It is particularly suited for making a variety of concrete components including components with 2 dimensional and 3 dimensional features such as wall panels, drainage pits, columns, culverts, beams etcetera. The method may also be used for other castable materials. For convenience the invention is discussed in terms of concrete components.

[0018] The present invention provides an improved method of producing precast concrete components that can easily handle irregular shapes, voids and multiple discrete components. A casting bed is first filled with a casting medium such as gypsum. Once set the desired component shape is cut into the casting medium and

2018271273 27 Nov 2018 the shape of the component removed to leave a mould of the exact shape required, either 2 dimensional or 3 dimensional. Reinforcing elements and fittings as desired are placed in the mould which is then filled with concrete. Once set the concrete component is removed from the mould and the casting medium recycled.

[0019] A schematic representation of the concrete casting system 10 is shown from above in Figure 1 and partially from side on in cross section in Figure 2. The system comprises a casting bed 20 with walls 21 for containing a casting medium 22 into which a series of casting moulds 51-54 are cut. The bed can be of any convenient shape and size, with a rectangle being a convenient choice. The bed and walls are preferably made of steel for durability and ease of cleaning. On either side of the bed are rails 30 on which a gantry 40 traverses the length of the bed (x-axis). The gantry is used to hold various tools 42, discussed below, which traverse the gantry across the width of the bed (y-axis). At the end of bed is a hopper 24 for collecting used casting medium for recycling. The rails 30 extend beside the hopper to allow the gantry to be used to deposit casting medium into the hopper using the gantry. The casting bed also includes movable cross members 26 to create regions of the casting bed that can be used independently. This readily supports different depth beds of casting medium and allows small areas of the bed to be used without the need to fill the complete bed with casting medium. Any desired number of regions may be created. Depending on the job mix of a factory, beds more suitable to particular components may be deployed, for instance long narrow beds for casting concrete beams, or rectangular beds for panels. The bed shown also includes a step 27 to provide a shallow area adjacent to the arrowed line 28 which will accommodate most jobs, and a deep area adjacent the arrowed line 29 in which extra deep castings can be produced. A number of different depth areas is clearly possible. The areas and regions may align, or be configured independently depending on the jobs at hand. Also shown in the bed are four different casting moulds 51-54 representing different aspects of the casting system. .

[0020] Figure 2 shows a cross sectional view of the casting bed 20 and the four casting moulds 51, 52, 53 and 54 which demonstrate differing techniques for obtaining a desired depth of casting. The casting bed is divided by cross member 26 into a first region adjacent arrowed line 61 and a second region adjacent arrowed line 62, independent of shallow area 28 and deep area 29. The first region has been filled with casting medium to a first depth 63 allowing moulds of that depth such as 51 to be very easily produced as the entire depth of the casting medium is removed to produce the

2018271273 27 Nov 2018 void into which the concrete is poured. A second mould 52 is also in this region but is of a shallower depth which has been accommodated by cutting the top of the moulding casting medium after it has set in an excavated region 70 to an excavated depth 71 to match the desired depth of the casting. The second region 62 is filled with casting medium giving a second depth 64, in the first area and a third depth 65 in the second area. In the second region the casting medium has been removed just to the depth of the castings. Mould 53 includes a step 82 and an angled wall 82, features that would be very difficult to produce in a conventional system. Mould 54 is positioned in the deep area of the bed which can accommodate its large dimensions. Not shown are screeding pits adjacent to each casting to receive excess concrete collected during screeding of the castings. To summarise, moulds of different depths can be produced by varying techniques; pouring the moulding casting medium to the desired depth, e.g. mould 51; cutting the top of the moulding casting medium to the desired depth, e.g. mould 52; or, cutting into the moulding casting medium to the desired depth, e.g. moulds 53 and 54.

[0021] The gantry 40 is used to carry various tools 42 over the casting bed 20 for the various tasks in the moulding process. The tools used fall into five broad categories: pumping tools, cutting tools, finishing tools, lifting tools and cleaning tools and are well known tools adapted for use in the system. All the tools can move across the gantry 40 to access the width of the casting bed and as the gantry moves along the rails the tools move along the length of the casting bed (and over the hopper if desired). Most of the tools can also be moved vertically (z-axis) to handle different depths of moulding casting medium. A five axis robotic arm is particularly suited for holding the various tools to give maximum flexibility.

[0022] The pumping tools include a first hose for transferring liquid casting medium into the casting bed, and a second hose for transferring concrete into moulds. Preferably the hoses include a valve near their outlet to eliminate unwanted flow, particularly for the concrete hose when moving between moulds.

[0023] The various cutting tools are used to cut through the moulding casting medium to produce the moulds. Standard milling bits are particularly suited, however many forms of cutting implements may be used depending on the material and features required. Suitable cutting implements include high pressure water cutters, lasers, rotating blades, rotating drums, and grinding wheels. The cutting tools are also used

2018271273 27 Nov 2018 for freeing the moulding casting medium from the side of the castings once they are set, and cutting the moulding casting medium into manageable sized pieces for removal. The cutting tools included in the system depend on the complexity of the moulds required. A simple mould such as 51 can be produced with only a laser or waterjet cutter for instance with coarse z-axis control. To produce a complex mould such as 53 a milling bit is used with fine three axis control.

[0024] The finishing tools include a vibrator to eliminate any air pockets in the moulding casting medium or moulded panels; a screed for removing excess moulding material or concrete; and, a concrete finisher to smooth the surface of the concrete.

[0025] The lifting tools include a simple hoist for lifting the cured castings from the casting bed, and a screw bit which screws into the excess moulding material so it may be lifted from the casting bed and placed into the hopper for recycling.

[0026] The final tools are cleaning tools for removing any moulding casting medium which remains on the casting bed after the bulk of the excess moulding casting medium has been removed. These tools include rotating brushes, waterjets and vacuums.

[0027] The method of making a concrete component with the system is as follows.

[0028] The moulding bed is first cleaned with the aid of the various cleaning tools to remove any traces of casting medium or concrete. The mould is then coated with a mould release agent.

[0029] If required, cross members are put in place to divide the casting bed into regions. The various regions are then filled to the required depth with casting medium. Air pockets are removed from the casting medium with vibrating tools and the surface is then screeded to ensure a uniform level.

[0030] Once the casting medium has set, a rotating drum may be used to reduce the depth of sections of a region for casting moulds such as 52. The outline of the casting moulds are then cut with either a milling bit, waterjet, laser or rotating blade depending on the complexity of the mould.

[0031] Excess casting medium is then removed from the casting mould. For simple moulds such as 51 and 52 this is done by a screw tool being driven into the casting medium and then lifted. The excess material is then moved using the gantry and

2018271273 27 Nov 2018 dropped into the recycling hopper. For casting moulds such as 53 or 54 in which the bottom of the mould is above the casting bed, cutters are used to remove the excess material, the cutter chosen depending on the complexity of the mould. Milling bits with three axis control are preferably used for complicated features. Vacuum attachments to the cutters extract the excess moulding material for recycling.

[0032] The casting mould is then coated with a mould release agent, reinforcing material, conduits, lugs etcetera placed into position and then the moulds are filled with concrete. Vibration tools are used to remove any air pockets from the concrete which is then screeded before finishing with a concrete finisher.

[0033] Once cured the outline of the concrete is traced with a water jet to free the concrete from surrounding casting medium. The concrete panels are then lifted from the bed using the embedded lugs. The panels may be lifted with aid of the gantry 40, or with the aid of a secondary gantry or crane depending on the weight of the panels. Any moulding material sicking to the concrete is removed for recycling.

[0034] The remaining casting medium is then cut it to manageable sized pieces if required and then lifted from the casting bed and placed in the recycling hopper. The casting medium is then crushed, and in the case of gypsum dehydrated, before being stockpiled for reuse.

[0035] The casting bed is then cleaned ready for re-use.

[0036] The above disclosure has described a single bed and a single gantry to manoeuvre the various tools. In such a system the throughput is limited by the drying time of both the casting medium and the concrete, however it can be increased by various means. A first means to increase throughput is to use multiple mobile casting beds that can be wheeled into position under the gantry for a procedure and then moved out of the way whilst the casting medium or concrete is drying. Multiple casting beds may also be used in conjunction with multiple gantries, where each gantry performs a subset of procedures and the casting beds move between the gantries. Any number of gantries and casting beds may be used to increase throughput.

[0037] The reader will now appreciate the present invention which provides an improved method of casting material that can easily accommodate irregular shapes, voids and multiple panels simultaneously.

2018271273 27 Nov 2018 [0038] Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in this field.

[0039] In the present specification and claims (if any), the word comprising and its derivatives including comprises and comprise include each of the stated integers but does not exclude the inclusion of one or more further integers.

Claims (8)

1. A method of casting a material, comprising the steps:

a) filling a casting bed with a casting medium;

b) cutting a casting mould into the casting medium; and

c) filling the casting mould with the material.

2. A method of casting material as in claim 1, further comprising the step of recycling the casting medium.

3. A method of casting material as in claim 1 or claim 2, further comprising the steps of dividing the casting bed into first and second regions using a separator, filling the first region to a first depth with casting medium, and filling the second region to a second depth with casting medium.

4. A method of casting material as in claim 1 or claim 2, wherein the casting bed includes a step delineating a first area of a first depth and a second area of a second depth.

5. A method of casting as in any one of claims 1 to 4, wherein the casting mould is cut into the casting medium to the depth of the casting bed.

6. A method of casting as in any one of claims 1 to 4, wherein the casting mould is cut into the casting medium to less than the depth of the casting bed.

7. A method as in claim any one of the previous claims, wherein the casting medium is gypsum.

8.

A method as in claim any one of the previous claims, wherein the material is concrete.