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Title:
A DEVICE FOR PRESSING CURVED BOARDS, PARTICULARLY LAMINATED BOARDS
Document Type and Number:
WIPO Patent Application WO/1997/026130
Kind Code:
A1
Abstract:
The invention relates to a press intended for the pressure molding of curved boards, in particular laminated boards, which press comprises a body (13), a base (11), a compression plug (12) supported by the body, and power means for the pressure molding of a board, or layers forming a laminated board, between the base and the compression plug. According to the invention the base (11) comprises a frame (14) supporting curved support structures or support arcs (21, 22, 23...) attached to it at a certain distance from one another with bearings. The press further comprises devices for rotating the support arcs (21, 22, 23...) around their bearing axes (21ab, 22ab, 23ab) and for locking them in the desired position, whereupon the surface (20, 20') formed by adjacent support arcs locked in the said position corresponds to the desired board curvature.

Inventors:
HUUHKA PERTTI (FI)
HUPPONEN MATTI (FI)
Application Number:
PCT/FI1997/000017
Publication Date:
July 24, 1997
Filing Date:
January 14, 1997
Export Citation:
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Assignee:
HUUHKA PERTTI (FI)
HUPPONEN MATTI (FI)
International Classes:
B27D1/08; B29C33/30; B29C53/04; (IPC1-7): B30B9/28; B30B7/00
Foreign References:
FR2565157A11985-12-06
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Claims:
CLAIMS
1. A device intended for the pressure molding of curved boards, in particular laminated boards, which device comprises a body (13), a base (11), a compression plug (12) bearing on the body, and power means for compressing the board, or the layers forming a laminated board, fitted between the base and the compression plug, the base (11) comprising a substantially horizontal frame (14) on which curved support structures, i.e. support arcs (21, 22, 23...) are supported at a certain distance from one another with bearings, characterized in that.
2. the bearing axes (21ab, 22ab, 23ab... ) of the support arcs (21, 22, 23....) are at the ends of the support arcs, and that.
3. the device further comprises means for rotating the support arcs (21, 22, 23...) around their bearing axes (21ab, 22ab, 23ab...) and for locking them in the desired position, the surface (20, 20') formed by adjacent support arcs locked in the said position corresponding to the desired board curvature.
4. A device according to Claim 1, characterized in that all of the support arcs (21, 22, 23...) are connected to one and the same connecting part (50) by the movement of which all of the support arcs (21, 22, 23...) can be caused to have an equal inclination.
5. A device according to Claim 2, characterized in that the base is rectangular, dimensioned for the pressure molding of standardsized boards,.
6. to each support arc (21, 22, 23...) there is attached a platelike lever arm (31, 32, 33...) extending from the outer circumference of the arc, and the connecting part (50) is a bar extending in the longitudinal orientation of the base (11), the bar being.
7. articulated to the lever arms (31, 32, 33...).
8. A device according to Claim 3, characterized in that it comprises power means, such as a hydraulic cylinder (51) with its auxiliary devices, for moving the said bar (50).
9. A device according to any of Claims 2 4, characterized in that it comprises a support mat (70) which is flexible in its lateral direction and rigid in its longitudinal direction and which is intended for being positioned as a base for the board of boardlayer stack to be pressure molded, on top of the support arcs (21, 22, 23...) locked in the desired inclination.
10. A device according to any of Claims 1 5, characterized in that it comprises an air or liquid cushion (60) which is intended for being positioned between the compression plug (12) and the board or boardlayer stack to be pressure molded and via which the molding pressure is directed to the board or boardlayer stack to be pressure molded.
11. A device according to any of Claims 1 5, characterized in that the compression plug (12) comprises a substantially horizontal frame on which compression arcs at a certain distance from one another are supported with bearings, and that the device further comprises means for rotating the compression arcs around their bearing axes and for locking them in a desired position in such a manner that the shape of the surface formed by the adjacent compression arcs locked in the said position will follow the surface (20, 20') referred to in Claim 1.
Description:
A DEVICEFORPRESSINGCURVED BOARDS, PARTICULARLY LAMINATEDBOARDS

The invention relates to a device intended for pressure molding of curved boards, in particular curved laminated boards .

The design of various specialized premises, for example on luxury liners and in luxury hotels, presupposes the use of curved-surface building boards . Partition walls and furnishings on such premises are based on curved building boards having shapes which correspond primarily to parts of cylindrical mantles of different radii of curvature.

The fire-safety regulations for ships require laminated boards which have a so-called non-asbestos layer of at least 19 mm. This board is of a gypsum- or stone-based non- combustible material, which is very brittle and soft. The non-asbestos layer may be in one or several different layers with laminate layers on both sides. The laminate layers are typically salt-impregnated, fiber-based non- combustible material layers. A typical laminate structure is, for example, one in which a laminate sheet is glued between two non-asbestos sheets, and there will be laminate layers on the other surfaces of the non-asbestos sheets.

According to the state of the art, curved laminated boards are fabricated by using a mold consisting of a lower part and its counterpart. The layers to be compressed, forming the laminated board, are placed between these mold parts . The mold and the layers in it are then lifted into a press . The lower part of the mold is usually a longitudinally straight and laterally bent plywood sheet which is supported by a base and rests on curved-profile transverse parts made of chipboard or the like, of which there must be a large number to provide an even surface. The plywood sheet is bent so that its curvature corresponds to the

curvature of the laminated board to be fabricated. The counterpart is made in the same manner.

The method described above has several disadvantages. The construction of the mold is very cumbersome. The lifting of the mold and the layers therein onto the press table is very heavy. A wood-bottomed mold made from plywood sheets or chipboards cannot, at least in any simple way, be arranged so as to be heated. Heating of the mold would be highly desirable in order to shorten the required pressure- molding time. The greatest problem in this technique is, however, that the fabricated mold is, of course, suited for only a certain board curvature. In the spaces for which curved laminated boards are needed there are typically wall and fixture surfaces of many different radii of curvature. Thus a separate mold has to be made for each surface curvature. In practice the molds must be regarded as single-use items, since the storing of numerous different molds for future needs would require very much space.

An object of the present invention is to eliminate the problems described and to provide a novel device by means of which it is possible to fabricate laminated boards of many different radii of curvature merely by setting the members of the device in the desired position. In a device such as this it is also much easier to provide heated compression, when so desired, than in a state-of-the-art mold system.

The characteristics of the invention are stated in Claim 1.

The invention is described below with reference to the accompanying drawings, wherein

Figure 1 is a perspective representation of a press according to the invention, Figure 2 depicts the base of the press of Figure 1 and the support arcs attached to it with bearings,

Figure 3 depicts a side view of the support arc series of the base of Figure 2, together with the devices for moving them,

Figure 4 depicts one support arc together with the devices for moving it, as seen from an end of the press,

Figure 5 depicts an enlargement of a lug attached to the lever arm of a support arc and its articulation to the bar for pushing the support arcs,

Figures 6A and 6B illustrate the operation of the device, and

Figure 7 depicts a support mat to be placed on top of the support arcs.

Figure 1 shows the main features of a press 10 according to the invention, having a base 11, corresponding to a platen, and a compression plug 12, which are connected to the body 13 of the device. In the figure, the compression plug 12 is movable in the vertical direction in the manner indicated by arrow. Alternatively it would also be possible to arrange the base to be movable. The power unit of the press may be a hydraulic system or mechanics driven by an electric motor (not shown in the figure). The figure shows that the surface 20 supported on the base is curved. On top of the surface 20 there rests a support mat 70, which is shown in greater detail in Figure 7.

Figure 2 shows in greater detail the base 11, which comprises a rectangular frame 14 bearing on the floor. To the side members 15 of the frame 14 there are attached with bearings successive curved support structures, or support arcs 21, 22, 23..., which are positioned at a certain distance from one another. The side member 15 is cut for the purpose that the structure left behind it should be seen more clearly. To the lower surface of the support arcs, i.e. to the outer circumference of the arcs, there are connected lever arms 31, 32, 33..., at the ends of which the devices for rotating the arcs are attached.

Although in principle the lever arms 31, 32, 33... could be

just bar-like parts attached at the middle of the arcs, a much sturdier structure is obtained in the manner shown in the figure, in which case the lever arms 31, 32, 33... are flat pieces attached to the outer circumferences of the arcs along the length of the arcs 21, 22, 23... In the middle area of the lower edges of the lever arm plates 31, 32, 33... there are attached lug pairs 41, 42, 43..., which are articulated to a bar 50 running in the longitudinal direction of the base. By an axial movement of the bar 50 (at which time the bar at the same time rises upwards) all of the support arcs can be rotated through an equal angle around their support axes 21ab, 22ab, 23ab... Each lug pair 41 consists of two parts 41a and 41b, and a lug pair is connected to the bar 50 by means of a pin which runs through holes 41c and corresponding holes in the bar 50. The last-mentioned details are shown more clearly in Figures 3 - 5.

Figure 3 shows a side view of the press according the invention. The ends 21b, 22b, 23b... of the rotation axles of the support arcs 21, 22, 23... are supported on the side member 15 of the base; only the upper edge of the member is shown. Reference numerals 21c, 22c, 23c... indicate the middle points of the said arcs, these middle points being at the same time the lowest points of the arcs. The arcs 21, 22, 23... are rotated around the axles 21b, 22b,

23b..., whereby the lowest points 21c, 22c, 23c... of the arcs are raised, from which it follows that the curvature gradient of the upper surface formed by the arcs becomes lower. This is seen more clearly in Figures 6A and 6B. The rotation movement of the arcs is produced by movement of the bar 50, the movement of the bar being transmitted to the arcs. The movement of the bar 50 is produced by means of a hydraulic cylinder 51 which is supported on the frame and the end of which is articulated by means of a pin 41d to the first lug pair 41 at the first end 50a of the bar 50. Under the effect of the hydraulic cylinder 51 the bar moves obliquely upwards in the manner indicated by an

arrow. When the arcs 21, 22, 23... have been moved to the desired inclination, the movement of the bar 50 is stopped and the bar is held in place. During the pressure molding of a laminated board it is important that the bar remains absolutely stationary. The return movement of the bar can be prevented, for example, by arranging a mechanical support part or some other braking mechanism between the base end and the second end 50b of the bar.

Figure 4 is an end view of the press. The figure shows one support arc 21 and a lever arm plate 31 connected to it, as well as a lug pair 41 and the bar 50. The axle ends 21a and 21b of the support arc 21 are attached with bearings to the side members 15 of the frame of the base. Figure 5 is an enlargement of a section through the line in Figure 4. It shows with dashed lines the position of the bar 50 relative to the lever arm plate 31 and the lug pair 41 when the rotation angle β is 90 degrees (Figure 6A) . The support arc 21 and the lever arm plate 31 may also from the start be made in one piece.

Figures 6A and 6B are presented to illustrate the operation of the device. Figure 6A is a longitudinal section along the center line of the press, and Figure 6B depicts the profile of the curved surface 20 and 20' formed by the support arcs, as seen from the end of the press. In Figure 6A there are depicted with continuous lines two adjacent support arcs 21 and 22 and, connected to them, the above- described lever arms 31 and 32, lug pairs 41 and 42, and bar 50, with the support arms 21 and 22 in their resting position. Reference numerals 21ab and 22ab indicate the positions of the rotation axes of the arcs. The surface 20 formed by adjacent arcs in the resting position (i.e. the surface which connects adjacent arcs) has the same curva¬ ture as have the support arcs themselves . The dashed lines show a situation in which the above-mentioned arcs have been rotated through about 45 degrees around their axes 21ab respectively 22ab. If the rotation movement of the

arcs is continued up to 90 degrees, the arcs will in their entirety be in the plane of their rotation axes, i.e. the surface formed by adjacent arcs will be flat. The curvature of the surface 20' of adjacent inclined arcs always has a lower gradient than the curvature of adjacent arcs in the resting position. The curvature gradient of the surface 20' becomes lower and will ultimately become flat as the angle β increases from zero to 90 degrees. By using the same support arc series 21, 22, 23... it is thus possible to fabricate laminated boards which have the same or greater radius of curvature than have the support arcs themselves . Most curved boards for the fabrication of curved walls and fixtures can be fabricated by means of a support arc series having a rotation radius of about 1.5 m. Although the support arcs are arcs of a circle, the surface 20' formed by rotated support arcs will deviate from the shape of a circle arc. However, the deviation is infinitesimal and without significance in these applications.

Figure 7 shows a support mat 70, which is intended for placement on top of the support arcs. The caterpillar-band¬ like mat 70 is made up of adjacently positioned metal tubes having a rectangular cross-sectional profile, the tubes being linked together by transverse bands 71, 72, 73..., which allow the mat to be flexed in the lateral orientation. The metal tubes ensure that the mat will remain rigid in its longitudinal orientation. The mat 70 constitutes the base for the board or the board-layer stack to be pressure molded.

When the board or board-layer stack to be compressed has been positioned in place, it is necessary to place a suitable counterpart on top of it before turning the molding pressure on. Figure 3 shows under the compression plug 12 an air cushion 60, via which the board or board- layer stack to be pressure molded is subjected to pressure. The air cushion will shape completely according to the curvature of the object being pressure molded.

Instead of the air cushion it would in principle also be possible to use a liquid cushion. By means of air or liquid cushions it is also possible to provide heating at the pressure-molding stage. It is also possible to arrange heating under the object to be pressure molded; under the support arcs there is space left for possible wires and other such equipment.

The counterpart to be used in pressure molding may also be fabricated according to the same principle as the lower part described above. The compression plug 12 comprises a substantially horizontal frame. To bear on this frame it is possible to attach with bearings compression arcs at a certain distance from each other, in a manner corresponding to that described above. These compression arcs can be arranged to rotate around their bearing axes, and they can be locked in the desired position in a manner corresponding to that described above. The surface formed by adjacent compression arcs locked in the final position must be shaped so that it will function as a counterpart for the surface 20, 20' .

The above description, illustrated in the figures, is to be regarded only as an example of the device according to the invention. Although laminated boards fabricated for special buildings have been especially emphasized as a use for the invention, it is clear that the device is equally well applicable in other fields, for example in the woodworking industry. By using a press according to the invention it is, of course, also possible to mold boards consisting of only one layer, provided that the material is moldable.

The mechanism (lever arm, lug, bar) for rotating the arcs presented above is, of course, only one embodiment example. In terms of the invention it is not essential that the rotating of the arcs is performed exactly in the manner described; any functioning rotation mechanism is usable.

The invention is also hot limited to the production of cylindrical board surfaces; the invention also covers the shaping of more or less spherical surfaces. A spherical surface is obtained, for example, by tilting the different support arcs of the press differently. In this case a support mat which is suitably flexible also in its longitudinal direction must be used.

The inclination of the arcs may also be processor- controlled in such a manner that the rotation radius of the curvature of the board to be fabricated is fed into a programmed processor, whereafter the processor will calculate the required angle of inclination of the arcs and control the movement of the devices rotating the arcs .

Of course, the power unit for rotating the support arcs may be, instead of a hydraulic system, a mechanical system driven by, for example, an electric motor.

For an expert in the art it is clear that the different embodiments of the invention may vary within the scope of the claims presented below.