MOULD AND METHOD OF MAKING SAME

Abstract: A method of making elongate strips of a mouldable material using a circular rotatable die wheel (28) having a profiled recess (27) extending around the periphery of a die wheel and rotating and moving the die wheel against a backing surface, the mouldable material being provided between the backing surface and the wheel. Also disclosed is a method producing a die wheel using suitable settable materials.

Description: MOULD AND METHOD OF MAKING SAME TECHNICAL FIELD: This invention relates to moulding articles of a mouldable material by compressing the material and is concerned with a method of making a mould for this purpose. The invention is concerned primarily, though not exclusively, with moulding elongate ornate articles and with moulding a continuous ornate strip of synthetic wood paste. BACKGROUND ART: The carvings of so called "carved furniture" are very seldomly done by hand today. Instead, a craftsman carves a prototype of an article, such as a furniture leg or a corner or edge moulding, and this is then reproduced using suitable machines and techniques. One technique is mainly mechanical and uses a pantograph to guide a carving router that cuts directly into natural wood or into a wood composite. Another is a moulding technique that uses a die or mould to compress a wood paste. The wood paste is composed of a binder and wood flour (usually obtained as residue from sanding) that sets after time and can be stained, painted, sanded, polished, etc. to have the appearance of natural wood. This invention is concerned with the latter technique. The known technique uses a flat die which is filled with the wood paste, inverted and placed on a backing board that is coated with a release agent or placed on a board (veneered composite or natural wood) that is coated with a suitable glue in the appropriate region, and then compressed using a hydraulic press and the like. The available presses and dies determines the maximum size of the mouldings as well as the quantity thereof made during each pressing. This invention seeks to provide a method for moulding elongate strips from wood paste that does not require expensive capital equipment and enables strips of unlimited length to be made. DISCLOSURE OF THE INVENTION: One aspect of the invention provides a method of making elongate strips of a mouldable material using a die having a recess profiled with a negative image of the strip to be formed, including the steps of:- ~ forming the die as a profiled recess extending around the periphery of a die wheel; -- positioning the die wheel adjacent a backing surface; and -- rotating the die wheel, the mouldable material being provided between the backing surface and the wheel. The backing surface may be substantially planar, in which event the die wheel is rotated and the die wheel and backing surface move relatively to each other. Alternatively, the backing surface may be provided by a second wheel with a round cylindrical rim. Alternatively, the backing surface may be provided by a belt, stiffening reinforcement being provided on the reverse side of the belt in the region of contact of the die wheel with the belt. The stiffening reinforcement may be an end roller for the belt or a substantially planar body positioned along a linear run of the belt in use. The mouldable material may be provided on the backing surface, the material being shaped and cut by the die wheel. Alternatively, the mouldable material may be introduced, such as by injection or pouring, into the region formed between the die wheel and the backing surface. Another aspect of the invention provides a method of producing a die wheel for forming a moulded article comprising a profiled recess that extends around the periphery of the die wheel, including the steps of:- - creating a prototype of the article to be moulded; - forming a negative impression of the prototype by suitably covering the prototype with a suitable first settable material, allowing the material to set and de-moulding the prototype, the prototype being optionally coated with a suitable release agent; - making a positive of the article to be moulded by moulding a suitable second settable material using the negative impression and allowing the material to set, the second settable material being capable of being flexed after setting; -- fixing the positive circumferentially inside a bore in a body; - positioning a hub axially within the bore in the body, an annular space being formed between the body and hub; - introducing a third settable material into the annular space and allowing the third settable material to set, the third settable material being substantially unyielding when set, the positive and the inner wall of the hoop being optionally coated with a suitable release agent; and -- removing the body and positive from the set third settable material and hub. Preferably the first and third settable materials for forming the negative impression are hard or substantially unyielding when set. Suitable materials are: epoxy resin, so called rigid polyurethanes and the like materials that are castable with relatively little difficulty and simple equipment. The second settable material may be a suitable synthetic rubber, silicone rubber and the like. A settable wood paste that is flexible when suitably treated may also be used, especially when the product to be moulded is wood paste and as such the wood paste is readily available. The prototype of the article to be moulded may be carved or fabricated by combining suitable carved and/or previously moulded elements. The invention also includes moulded articles and products to which the moulded articles are attached that are made by the method of the invention or using the die wheel made according to an aspect of the invention. The invention also includes a die wheel made by the method of the invention. Further features, variants and/or advantages of the invention will emerge • from the following non-limiting description of an example of the invention made with reference to the accompanying schematic drawings. BRIEF DESCRIPTION OF THE DRAWINGS: Figure 1 shows end and plan views of a prototype of an elongate strip that is to be moulded; Figure 2 shows end and plan views of an elongate negative impression formed using the strip of Figure 1 ; Figure 3 shows end and plan views of a positive made using the negative impression of Figure 2; Figure 4 shows an axial section through a body with the positive of Figure 3 being affixed to the inner wall of a bore in the body; Figure 5 shows an axial section of the body of Figure 4 and a spaced hub mounted on a support; Figure 6 shows an axial section of the combination of Figure 5 into which a settable material has been cast; Figure 7 shows an axial section through a die wheel formed by removing the body from the combination of Figure 6; Figure 8 shows a side view of a die wheel of Figure 7; and Figure 9 shows an example of the die wheel of Figure 8 in use for forming an elongate moulded strip of wood paste. BEST KNOWN MODE FOR CARRYING OUT THE INVENTION: In the drawings the same or similar parts have the same reference numbers, certain parts having sub-numbers to identify them as part of a component or as substantially equivalent parts in different embodiments. Relief, ornamental elements of the moulding are shown with hatching in order better to illustrate the positive and negative natures of the items. Figure 1 shows end and plan views of a prototype 10 of an elongate strip that is to be moulded, the strip having ornamentation 12 that is formed as a combination of relief elements 12.1 to 12.4. The prototype is made by carving a strip of wood of arcuate cross-section or by combining previously moulded elements into a strip or applying ornamental reliefs to a backing and the like. Figure 2 shows end and plan views of a negative impression or mould 14 formed by placing the prototype in an elongate receptacle, applying a release agent such as wax, PVA release agent, silicone spray and the like to the receptacle and prototype, mixing and pouring a hard setting polyurethane composition into the receptacle and allowing the polyurethane to set. Figure 3 shows end and plan views of a positive 16 of set wood paste moulded using the mould 14. While the prototype 10 and positive 16 look alike they differ in that the latter is flexible or is able to be made to be so by heating and/or moistening or wetting. Figure 4 shows an axial section through a body 18 having a round bore 18.1 therethrough, with the positive 16 extending circumferentially around the bore and being bonded to the body. The body 18 is formed by laminating a plurality of wood composition boards and cutting a circular hole therein. Figure 5 shows the body 18 and an axially positioned circular hub 20 of wood mounted on a base board 22. The body, hub and base board define a moulding cavity 24. In Figure 6 hard setting or so called "rigid" polyurethane 26 is cast into moulding cavity. Figure 7 and 8 show respectively an axial section and a side view of a die wheel 28 supported on an axle 30, the die wheel being formed by cutting through and removing the body 18 and positive 16 from the cast polyurethane 26 to leave a circular profiled die cavity 27. Figure 9 shows an example of moulding a wood paste using the die wheel 28. In this event the die wheel is supported above a backing board 32 that has been coated with a release agent, the die wheel having its axis horizontal and its rim pressed against the board 32. An injection spout 34 having a mouth 34.1 is provided such that the mouth faces into the region of the die cavity 27 adjacent the board. In use, the die wheel is rotated slowly by a motor through suitable gearing. This causes the board 32 to move beneath the die wheel. Wood paste 36 is forced through the spout so that it can be compressed and shaped between the die wheel and backing board. Benefits of the moulding method are that it can be performed quickly using relatively inexpensive machinery and equipment and strips of indefinite length can be formed as desired. The die making method is simple, quick and inexpensive to put into effect, and dies made using the method are suitably inexpensive for multiple shapes and limited production runs. The invention is not limited to the precise details described above and shown in the drawings. Modifications may be made and other embodiments developed without departing from the scope of the invention.

Claims: CLAIMS: 1. A method of making elongate strips of a mouldable material using a die having a recess profiled with a negative image of the strip to be formed, characterised by including the steps of:- ~ forming the die as a profiled recess extending around the periphery of a die wheel; -- positioning the die wheel adjacent a backing surface; and ~ rotating the die wheel, the mouldable material being provided between the backing surface and the wheel. 2. The method of claim 1 , characterised in that the backing surface is substantially planar, the die wheel being rotated and the die wheel and backing surface being moved relatively to each other. 3. The method of claim 1 , characterised in that the backing surface is provided by a second wheel with a round cylindrical rim. 4. The method of claim 1 , characterised in that the backing surface is provided by a belt, stiffening reinforcement being provided on the reverse side of the belt in the region of contact of the die wheel with the belt. 5. The method of claim 1 , characterised by positioning at least a strip of the mouldable material on the backing surface, and shaping and cutting the strip by moving the die wheel over the mouldable material. 6. The method of claim 1 , characterised by introducing the mouldable material into the region formed between the die wheel and the backing surface. 7. A method of producing a die wheel for forming a moulded article comprising, the die wheel having a profiled moulding recess that extends around the periphery of the die wheel, characterised by including the steps of:- - creating a prototype of the article to be moulded; - forming a negative impression of the prototype by suitably covering the prototype with a suitable first settable material, allowing the material to set and de-moulding the prototype, the prototype being optionally coated with a suitable release agent; - making a positive of the article to be moulded by moulding a suitable second settable material using the negative impression and allowing the material to set, the second settable material being capable of being flexed after setting; -- fixing the positive circumferentially inside a bore in a body; ~ positioning a hub axially within the bore in the body, an annular space being formed between the body and hub; -- introducing a third settable material into the annular space and allowing the third settable material to set, the third settable material being substantially unyielding when set, the positive and the inner wall of the hoop being optionally coated with a suitable release agent; and - removing the body and positive from the set third settable material and hub. 8. The method of claim 7, characterised in that the first and third settable materials for forming the negative impression are hard or substantially unyielding when set.f? 9. The method of claim 7, characterised in that the second settable material is a suitable synthetic rubber, silicone rubber and the like. 10. Moulded articles and products to which the moulded articles are attached that are made by the method of claim 7 or that are made using a die wheel made according to claim 1. 1 1 . A die wheel made by the method of claim 1 .

Inventors: LIPMAN BARRY, LIPMAN, BARRY
Applicants: LIPMAN BARRY, STEINHOFF MFG PTY LTD, LIPMAN, BARRY, STEINHOFF MANUFACTURING (PTY) LTD.
Application year: 2001
Main classification: B29C33
IPC codes: B29C33, B29C59, B44B5