A three-dimensional article This invention relates to a method of making a
three- dimensional article, to a three-dimensional article, and to a puzzle incorporating a three dimensional image.
Two-dimensional jig-saw puzzles are very well known and are very popular. Three dimensional jig-saw puzzles of various types are also known, one such puzzle being described in US 2003/0209854.Al.
According to the invention, there is provided a method of making a three dimensional article which has a contoured face and a flat base, wherein the contoured face has a printed image thereon matching the contours on the face, the method comprising the steps of producing a female mould, pressing one face of a deformable foamed plastics core sheet into the mould so that that face of the sheet permanently takes up the contours of the mould, removing the core sheet from the mould, printing a distorted image on a planar cover sheet, and applying the cover sheet to the deformed face of the core sheet so that the cover sheet follows the contours of the cover sheet face and the distortion of the image is removed as a result of the change of the cover sheet from being planar to a three- dimensional form.
Preferably a backing sheet of greater stiffness than the core sheet is applied to the core sheet on the core sheet face opposite to the deformed face to form a flat and stiff back to the article.
Preferably the cover sheet is laid in a mould before the core sheet is offered up to the cover sheet. The cover sheet can be applied to the core sheet using a solvent to weld the sheets to one another.
The cover sheet, the core sheet and the backing sheet can all be of EVA foam, preferably of differing densities.
The cover sheet can be provided with a matrix of pinholes, so that air is not trapped between the sheets when they are combined with one another.
After being formed, the article can be cut into individual pieces to make a jig-saw or other type of puzzle.
According to a second aspect of the invention, there is provided a three dimensional article which has a contoured face and a flat base, wherein the contoured face has a printed image thereon matching the contours on the face, the article comprising a foamed plastics core sheet deformed such that a face of the sheet permanently takes up the contours of the mould, and a cover sheet, initially printed with a distorted image, applied to the deformed face of the core sheet so that the cover sheet follows the contours of the cover sheet face and the distortion of the image is removed as a result of the change of the cover sheet from being planar to a three-dimensional form.
According to a third aspect of the invention, there is provided a puzzle comprising an article as set forth above and having a plurality of separate pieces, wherein the pieces are separated from one another by cutting in a direction at right angles to the plane of the core sheet.
The puzzle may be a jig-saw puzzle and the separate pieces can be cut so that they interlock with one another when the puzzle is put together.
The invention will now be further described, by way of example, with reference to the accompanying drawings, in which; Figure 1 is a prospective view of a mould for the manufacture of a three dimensional article in accordance with the invention; Figure 2 shows a first process step in accordance with the invention; Figure 3 shows a second process step; Figure 4 shows a third process step; Figure 5 shows a cover sheet before application to a moulded foam layer; Figure 6 shows the cover sheet of Figure 5 after application to the moulded layer; Figure 7 is a perspective view of a finished puzzle in accordance with the invention; and Figure 8 is a plan view of the puzzle of Figure 7.
Referring initially to Figure 1, a female mould 10 has a shape cut into the internal mould surface. In the example shown in the figures, the shape is the three letters A', B' and 0' (12, 14, 16) . The internal cavity of the mould is formed with indentations corresponding to each of these letters. The indentations can be of varying depth and can cover any proportion of the surface of the mould.
Where there are discrete indentations, they can be all of different depths, and the depth of each indentation can vary across it's area.
The mould 10 can be made of metal or of any other suitable material which will be stable under the process conditions, to be described.
The article is to be made from a foamed plastics material and a typical and suitable foam is an ethylene vinyl acetate foam (EVA foam) . A planar sheet of EVA foam 18 is pressed into the mould cavity of the mould 10, and through the application of heat and pressure those areas of the foam which are pressed against the non-indented surface of the mould are compressed while the areas which overlie the indentations 12, 14, 16 are not compressed or are compressed to a lesser extent. A permanent deformation takes place and the foam 18 permanently retains the shape of these indentations when removed from the mould, as can be seen from Figure 3, where the sheet 18 has been removed from the mould and turned the other way up. In the drawings, the edges of the (now relief) areas 12a, 14a, l6a, are shown with sharp edges. In practice however the nature of the moulding process and the materials used will mean that the vertical' walls at the edges of the raised relief areas will be sloping and will merge through curved transition areas into the flat upper surface of the characters.
It will be noted from a comparison of Figures 2 and 3 that the base thickness of the foam 18 has substantially reduced over the major part of the sheet, except where the characters l2a, l4a, l6a are present.
To make the article robust, the foam sheet 18 is mounted on a thick base foam layer 20 using a suitable adhesive.
The article is then much more rigid than would be the case if the sheet 18 alone were used without a backing.
Finally, a printed image layer 22 is applied over the relief surface of the moulded sheet 18. The image layer 22 is printed with distorted versions of the letters A', B' and C' using wire frame technology. The image layer 22 is applied to the relief face of the sheet 18, such that the image layer 22 which is very thin follows the contours of the moulded face of the sheet 18.
When the image layer is fully applied, the distortion apparent in the sheet when it is flat is removed such that the image appears undistorted when it has followed the contours of the moulded sheet 18.
As will be seen in Figure 4, the image layer 22 has a very large number of tiny holes 24, which will allow air to escape from between the layers when the two layers are combined. These pinholes 24 can typically be around 0.1 to 0.2 mm in diameter.
The image layer 22 can be attached to the moulded sheet 18 by spraying a layer of solvent onto the face of the moulded sheet or onto the back of the image layer and pressing the two together, preferably with a sculpted mask to apply pressure in all areas to ensure that the layers are in intimate contact over the whole surface area.
Figures 5 and 6 are included to show the contrast between the image layer 22 before application to the moulded sheet 18 ie with distortion (Figure 5) and after application to the moulded sheet ie without distortion (Figure 6) . As will be seen by a comparison between Figures 5 and 6, the letters (for example) in Figure 5 are shown flat and out of proportion, whereas when the three dimensional form of the sheet is created, the shape of the letters in three dimensions is in the correct proportions.
The starting point for the image is a three dimensional image. A wireframe' will be attached to that image in a known manner. If no three dimensional image is available depicting the desired appearance, a three dimensional representation must first be constructed, normally using computer modelling tools, from a two dimensional original.
The wireframe image is then converted to two dimensions, and the two dimensional image is printed on the flat sheet 10.
It should be noted that these drawings are schematic, to illustrate the principle and are not to be regarded as true to scale.
Once the image layer has been applied to the relief layer, the finished article can be divided up into jigsaw puzzle shape pieces as can be seen in Figures 7 and 8. The cuts which separate the pieces may travel across a raised face of the article, such that the position of the jigsaw cuts is independent of the image on the article. This can be seen for example at 26 in Figure 8.
The shape of the jig-saw pieces can be of a conventional interlocking form with lugs 28 and sockets 30, or of any other suitable form, not necessarily interlocking.
When the article is divided into pieces in t}i way, a suitable cutting operation is die-cutting, where a blade descends from above into the article to cut the pieces up.
The printed sheet 22 will preferably incorporate a colour image, with the colouring and/or pattern and/or image on the sheet registering with appropriate relief areas.
Although the use of the article as a jig-saw puzzle has been particularly described, the invention is not restricted to this use. the article can be used in games to create relief printed playing boards or robust playing parts or pieces. Additional features can be applied to the articles such as hair, fur or eyes. It may be possible to add electronic functionality to the pieces, possible by embedding circuitry within the foam.
Furthermore, the invention is not restricted to play articles and may find application in a wide variety of other applications.