EQUIPMENT FOR MAKING ARTICLES FROM PULP MATERIAL, AND SUCTION MOULD FOR USE IN SUCH EQUIPMENT

Abstract: The equipment comprises a suction mould (1) having a plate (2) with perforations (5) and a covering of wire gauze (6). A number of projections (8) in the form of hollow members (9) of plastic, e.g. high-density polyethylene, are secured on top of suitable openings (7) in the plate (2) and the wire gauze (6). The hollow members (9) are perforated (11) and covered with wire gauze (10) on the outside, and they are selected from a first modular system comprising a relatively small number of types of pre-fabricated projections (8) with different dimensions and shapes. The equipment can also comprise a pressing mould (not shown) for hot-pressing of a papier-mâché product made by using the suction mould, said pressing mould comprising a first mould part with projections complementary to and having the same dimensions and shape as the recesses in the papier-mâché product produced by the projections on the suction mould, and a second mould part with recesses complementary to the projections on the first mould part, but having dimensions larger than the latter by the thickness of the hot-pressed papier-mâché product. The projections of the first mould part are pre-fabricated and selected from a second modular system comprising a relatively small number of types with different dimensions and shapes, after shrinkage corresponding to the dimensions of the recesses produced in the papier-mâché product using projections according to the said first modular system.

Description: EQUIPMENT FOR MAKING ARTICLES FROM PULP MATERIAL. AND SUCTION MOULD FOR USE IN SUCH EQUIPMENT TECHNICAL FIELD The present invention relates to equipment of the kind set forth in the preamble of claim 1. BACKGROUND ART In equipment of this kind, the suction moulds are costly to produce, especially if they are to comprise a great number of projections or raised portions, as the sha¬ ping surface is produced by material-removing machining of a metallic blank, the shaping surface of which is formed by a through-going metal gauze having been shaped in its en- tirety. Such suction moulds can only be used profitably for making extremely great numbers of uniform products, such as e.g. egg trays or egg packages. Recently, the need has arisen for also being able to make smaller series of articles, e.g. thin-walled papier- -mache products of pulp material with raised portions or projections to be used as shock-absorbing filling bodies instead of moulded filling bodies of rigid porous plastic material between an external packaging means, e.g. a cor¬ rugated-paper box, and an article packaged therein, such as an electronic apparatus, a kitchen machine etc., said pro¬ jections or raised portions necessarily having various shapes and sizes and being located in a manner corresponding to the article to be packaged. DISCLOSURE OF THE INVENTION On the above background, it is the object of the present invention to provide equipment of the kind referred to initially, with which it is possible to fill the need mentioned above, and which can be produced at such low cost, that it makes it possible in a profitable manner to produce limited numbers of thin-walled or shell-shaped products of pulp material. This object is achieved with equipment, according to the present invention being characterized by the features set forth in the characterizing clause of claim 1. With this arrangement, it is possible to assemble a suction mould with the desired raised portions or projections from a small number of standardized and series-produced com¬ ponents, which may in certain cases be used again, so that the suction mould can be produced at substantially reduced cost. The invention also relates to a suction mould to be used in equipment according to the invention. A preferred embodiment for such a suction mould is set forth in claim 2. Another embodiment of the suction mould according to the invention is set forth in claim 3. The use of stainless steel makes the components concerned easy to clean and pro¬ tects them against electrolytic corrosion. The combination set forth in items b and c has proved suitable for achieving a homogenous deposition of pulp material on the shaping sur- face of the suction mould. A further preferred embodiment is set forth in claim 4. Especially high-density polyethylene is cheap and easy to shape at low cost to the desired shapes, while its hy- drophobic surface properties reduce the necessary cleaning of the suction mould. Yet another preferred embodiment is set forth in claim 5. A wire-gauze covering made in the manner indicated has proved to serve its purpose excellently, and the resi¬ stance welding of the wire gauze has proved not to reduce its permeability. With a view to easy separation of papier-mache pro¬ ducts made with a suction mould according to the invention and having them stacked on top of each other, the suction mould may also exhibit the features set forth in claim 6. With this arrangement, a protruding rib will be formed be¬ tween the ribs referred to on the side of the papier-mache product facing the suction mould, while on the opposite side of the product a projection with a relatively plane surface will be formed, said projection, when dried papier-mache products are stacked on top of each other and nested within each other, will abut against the protruding rib on the papier-mache product lying immediately above, thus producing a certain spacing from the latter. When the suction mould has been separated from the shell of pulp material having been aspirated onto it and this shell has been placed in the drying section of the equipment and dried so as to form a papier-mache product, in which process a certain drying shrinkage occurs depending on the production parameters, it is often preferred to hot- -press the papier-mache product, giving the latter a more dense consistency and a more smooth and an esthetically pleasing surface. For this reason, the present invention also relates to equipment of the kind set forth in the preamble of claim 7, and according to the invention, this equipment is charac- terized by the features set forth in the c a act rizing clause of said claim 7. with this arrangement it is possible to exploit the benefits of the modular-system arrangement set forth in claim 1 and used for making the suction mould. BRIEF DESCRIPTION OF THE DRAWINGS In the following detailed portion of the present specification, the present invention will be explained in more detail with reference to the drawings, in which Figure 1 is a partial plan view of the corner of a suction mould according to the invention, Figure 2 is a sectional view along the line A-A in Figure 1, Figure 3 is a sectional view along the line A-B in Figure 1, and Figure 4 is a partial sectional view through a region of a pressing mould according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Figures 1-3 show a corner of a suction mould generally designated 1. The suction mould 1 comprises a plane metal plate 2, along the periphery of which a so-called flushing edge 3 is secured by means of screws 4. The metal plate 2 is perforated by a number of through-going bores 5, prefer¬ ably with a diameter of 2 mm and having their centres spaced from each other by appr. 8 mm, the moulding surface of said metal sheet 2 being covered by 50-mesh metal wire gauze 6. Both the metal plate 2 and the metal wire gauze 6 are made of stainless steel. Projections generally designated 8 are secured to the metal plate 2 above suitable openings 7, each of said projections consisting of a hollow member 9 of high-density polyethylene, the external surface of which is covered with metal-wire gauze 10. The hollow members 9 are perforated by bores 11, like the bores 5 in the plate 2 having a diameter of 2 mm and preferably having their centres spaced approximately 8 mm apart. Like the metal-wire gauze 6 in the plate 2, the metal-wire gauze 10 is made from stain- less steel and has a mesh size of 50. As shown in Figure 3, the projections 8 are secured to the metal plate 2 by means of screws 12. The projections 8 shown in the drawing all have the same dimensions and the same shape, as they are shaped some- what like truncated cones with square base and rounded cor¬ ners. It is, however, to be understood that according to the present invention, the projections 8 may have various dimensions and shapes, such as similar to a truncated cone with a rectangular base and rounded corners, and they may have been selected among a modular system comprising pre- -fabricated projections of a relatively small number of types with different dimensions and shapes. In the corner of suction mould 1 shown in Figure 1, a pair of ribs 13 are placed close side-by-side between two of the projections 8. The purpose of these ribs 13 is to produce a recess with a downwardly protruding rib on the surface shaped by the suction mould 1 on the papier-mSche product made on this mould, and to produce a substantially plane raised portion on the opposite surface of the product, said rib and a corresponding raised portion on the next product lying below in a stack of nested papier-mSche pro¬ ducts having as their purpose to make it easier to separate stacked products from each other. Figure 4 is a partial sectional view of a region of a pressing mould according to the present invention, adapted for hot-pressing of a dried papier-mache product made with a suction mould according to the invention. The pressing mould consists of a first mould part generally designated 14 and a second mould part generally designated 15. The first mould part 14 comprises projections 16 of a shape complementary to the shape of the recesses produced in the dried papier-mache product by the shaping surface of the suction mould, while the second mould part 15 comprises recesses 17 of a shape complementary to the shape of the projections 16 on the first mould part, but having dimensions greater than the projections 16 on the first mould part enlarged by the wall thickness of the hot- -pressed papier-mSche product. Both the projections 16 and the recesses 17 may be produced by suitably machining metal¬ lic work pieces. The projection 16 shown in Figure 4 is pre-fabricated and chosen from second modular system comprising a relatively small number of types with different dimensions and shapes corresponding to the dimensions and shapes after shrinkage of the recesses produced in the papier-mSchέ product using projections according to the first-mentioned modular system described in connection with the suction mould related to with reference to Figures 1-3. In the exemplary embodiment shown, the projections 16 on the first mould part 14 are secured to a substantially plane metal plate 18 by means of screws 19. LIST OF PARTS 10 15 20

Claims: C L A I M S : 1. Equipment for making a thin-walled papier-mSche product from pulp material and comprising a suction mould (1) with flushing edges (3) and a shaping surface having projections (8) and covered with wire gauze (6,10), said projections having a suitable taper permitting problem-free liberation of the moulded product from the suction mould, characterized in a) that the suction mould (1) comprises a plane plate (2) provided with perforations (5) and covered by wire gauze (6) , and b) that the projections (8) are releasably secured (12) to the plate (2) above suitable openings (7) in the latter and in the wire gauze (6) and consist of perforated hollow em- bers (9) covered on the outside with wire gauze (10) , said projections being selected from a first modular system com¬ prising a relatively small number of types of pre-fabri¬ cated projections (8) with different dimensions and shapes. 2. Suction mould for use in an equipment according to claim 1, characterized in that the projections (8) have shapes resembling those of truncated cones with a substan¬ tially square or rectangular base with rounded corners, their oblique peripheral walls forming a taper angle with the normal on the surface of the plate (2) in the order og magnitude 8-20°, preferably appr. 15°. 3. Suction mould according to claim 2, characterized in that a) the plate (2) and the wire gauze (6,10) consist of stain¬ less steel, b) the perforations (5,11) in the plate (2) and the hollow members (9) are holes with a diameter of appr. 2 mm and a spacing between centres of preferably appr. 8 mm, and that c) the wire gauze (6,10) has a mesh size of the order of magnitude 50. 4. Suction mould according to claim 2 or 3, charac¬ terized in that the hollow members (9) used in the projec- tions (8) are produced by moulding and/or material-removing processing of a plastic material, such as nylon, polycar¬ bonate, polyester etc., preferably high-density polyethylene. 5. Suction mould according to claim 4, characterized in that a metal-wire-gauze covering (10) on the projections (8) has been produced by a method comprising the following steps: a) creating a suitably developed surface, b) cutting a pre-form of metal-wire gauze of a shape cor- responding to said developed surface, c) folding the pre-form to the desired shape and resistance- -welding of its edges to each other to retain the shape, and d) securing the shaped and welded wire-gauze shape to the surface of the hollow member of plastic (9) by heating. 6. Suction mould according to any one or any of the claims 2-5, characterized by at least one pair of short ribs (13) with suitable taper placed close side-by-side on top of the wire-gauze covering (6) in at least one location on the plate (2) , said ribs (13) either being made of metal- -wire gauze and secured to a metal-wire gauze on the plate by spot welding or made of e.g. polyethylene and removably secured to the metal plate by means of at least one screw. 7. Equipment for making a thin-walled papier-mache product of pulp material and comprising a pressing mould for hot-pressing of dried papier-mache product made with a suction mould as set forth in anyone or any of the claims 1-6, said pressing mould comprising a first mould part (14) with projections (16) complementary to the recesses in the dried papier-mache product produced by the shaping surface of the suction mould and having the same shape and dimensions as said recesses, and a second mould part (15) with recesses (17) complementary to the projections (6) on the first mould part (14) and having the same shape as the latter, the di- mensions of the recesses (17) , however, being increased by the wall thickness (t) of the hot-pressed papier-mache pro- duct relative to the dimensions of the projections (16) on the first mould part (14) , and in which the projections (16) on and the recesses (17) in the mould parts are produced by material-removing machining metal workpieces, charac- terized in that the first mould part (14) has been assembled with separate, pre-fabricated projections (16) selected from a second modular system comprising a relatively small number of types with different dimensions and shapes, after shrinkage corresponding to the dimensions and shapes of recesses produced in the papier-mache product using projec¬ tions according to the first modular system set forth in claim 1, said first projections (16) being releasably secured to a substantially plane metal base (8) . AMENDED CLAIMS [received by the International Bureau on 23 July 1993 (23.07.93) ; original claims 1 and 7 amended; remaining claims unchanged (3 pages) ] 1. Equipment for making a thin-walled papier-mache product from pulp material and comprising a suction mould (1) with flushing edges (3 ) and a shaping surface having projections (8) and covered with wire gauze (6, 10) , said projections having a suitable taper permitting problem- free liberation of the moulded product from the suction mould, wherein a) the suction mould (1) comprises a base surface (2 ) pro- vided with perforations (5) and covered by wire gauze, and wherein b) the projections (8) are releasably secured (12) to the plate (2) above suitable openings (7) in the latter and in the wire gauze (6) and consist of perforated hollow mem- bers (9) covered on the outside with wire gauze (10) , cha¬ racterized in that said base surface is a plane plate (2) and that said projections (8) are selected from a first building-set system comprising a relatively small number of types of pre-fabricated projections (8) with different di- mensions and shapes. 2. Suction mould for use in an equipment according to claim 1, characterized in that the projections (8) have shapes resembling those of truncated cones with a substan¬ tially square or rectangular base with rounded corners, their oblique peripheral walls forming a taper angle with the normal on the surface of the plate (2) in the order og magnitude 8-20°, preferably appr. 15°. 3. Suction mould according to claim 2, characterized in that a) the plate (2) and the wire gauze (6,10) consist of stain¬ less steel, b) the perforations (5,11) in the plate (2) and the hollow members (9) are holes with a diameter of appr. 2 mm and a spacing between centres of preferably appr. 8 mm, and that c) the wire gauze (6,10) has a mesh size of the order of magnitude 50. 4. Suction mould according to claim 2 or 3, charac¬ terized in that the hollow members (9) used in the projec¬ tions (8) are produced by moulding and/or material-removing processing of a plastic material, such as nylon, polycar- bonate, polyester etc. , preferably high-density polyethylene. 5. Suction mould according to claim 4, characterized in that a metal-wire-gauze covering (10) on the projections (8) has been produced by a method comprising the following steps: a) creating a suitably developed surface, b) cutting a pre-form of metal-wire gauze of a shape cor¬ responding to said developed surface, c) folding the pre-form to the desired shape and resistance- -welding of its edges to each other to retain the shape, and d) securing the shaped and welded wire-gauze shape to the surface of the hollow member of plastic (9) by heating. 6. Suction mould according to any one or any of the claims 2-5, characterized by at least one pair of short ribs (13) with suitable taper placed close side-by-side on top of the wire-gauze covering (6) in at least one location on the plate (2) , said ribs (13) either being made of metal- -wire gauze and secured to a metal-wire gauze on the plate by spot welding or made of e.g. polyethylene and removably secured to the metal plate by means of at least one screw. 7. Equipment for making a thin-walled papier-mache product of pulp material and comprising a pressing mould for hot-pressing of dried papier-mSche product made with a suction mould as set forth in anyone or any of the claims 1-6, said pressing mould comprising a first mould part (14) with projections (16) complementary to the recesses in the dried papier-mache product produced by the shaping surface of the suction mould and having the same shape and dimensions as said recesses, and a second mould part (15) with recesses (17) complementary to the projections (6) on the first mould part (14) and having the same shape as the latter, the di- mensions of the recesses (17) , however, being increased by the wall thickness (t) of the hot-pressed papier-mSche pro¬ duct relative to the dimensions of the projections (16) on the first mould part (14) , and in which the projections (16) on and the recesses (17) in the mould parts are produced by material-removing machining metal workpieces, charac¬ terized in that the first mould part (14) has been assembled with separate, pre-fabricated projections (16) selected from a second building-set system comprising a relatively small number of types with different dimensions and shapes, after shrinkage corresponding to the dimensions and shapes of recesses produced in the papier-mache product using pro¬ jections according to the first building-set system set forth in claim 1, said first projections (16) being releasab- ly secured to a substantially plane metal base (8) .

Inventors: JESSEN POUL ERIK, KJELDSEN IB JOERGEN, PIHL RENE, RASMUSSEN TORBEN, JESSEN, POUL, ERIK, KJELDSEN, IB, JOERGEN, PIHL, RENE, RASMUSSEN, TORBEN
Applicants: HARTMANN AS BRDR, BROEDRENE HARTMANN A/S
Application year: 1993
Main classification: D21J5
IPC codes: D21J5, D21J7