WO2001068351A1

WO2001068351A1 - Method for forming a three-dimensional construction

Info

Publication number: WO2001068351A1
Application number: PCT/NL2001/000209
Authority: WO
Inventors: Augustinus Wilhelmus Maria Bertels
Original assignee: Inventum B.V.
Priority date: 2000-03-13
Filing date: 2001-03-13
Publication date: 2001-09-20
Also published as: NL1014619C2; AU4891101A

Abstract

The invention relates to a method for forming a three-dimensional construction from a hollow sandwich panel (1), which consists of two boards (2) which are held at a mutual distance by spacer elements (3) extending mutually parallel and lying at a mutual distance, which method consists of reducing the bending stiffness of the sandwich panel (1) by reducing the stiffness of at least one of the boards, and bending the sandwich panel (1) round an axis of curvature such that in the area of the bending an inner board with relatively small radius of curvature and an outer board with relatively large radius of curvature are created, wherein according to the invention the bending stiffness of at least one of the boards is first reduced by deforming a part of the relevant board, and the sandwich panel (1) is subsequently bent round the axis of curvature formed by the deformed board part, and wherein the axis of curvature can also be straight or curved.

Description

METHOD FOR FORMING A THREE-DIMENSIONAL CONSTRUCTION

The present invention relates to a method for forming a three-dimensional construction from a hollow sandwich panel, which consists of two boards which are held at a mutual distance by spacer elements extending mutually parallel and lying at a mutual distance, which method consist of reducing the bending stiffness of the sandwich panel by reducing the stiffness of at least one of the boards, and bending the sandwich panel round an axis of curvature such that in the area of the bending an inner board with relatively small radius of curvature and an outer board with relatively large radius of curvature are created.

Such a method is known from the Dutch patent publication no. 8800102. In this known method the sandwich panel is bent round an axis of curvature which runs parallel to the spacer elements. A drawback of this known method is that the constructions to be obtained by applying this method are limited in respect of design, in that bending can take place in only one direction. In addition, the angle through which the sandwich panel can be bent is limited.

The object of the present invention is to provide a method for forming a three-dimensional construction wherein the drawbacks associated with the method known from the prior art are obviated. For this purpose the method according to the present invention is characterized in that the bending stiffness of at least one of the boards is first reduced by deforming a part of the relevant board, and that the sandwich panel is subsequently bent round the axis of curvature formed by the deformed board part. The axis of curvature can be straight or curved. The deforming is carried out by heating the part of the relevant board so that this part and the spacer elements situated thereunder fuse with the opposite board, and/or by cutting through the relevant board over cutting planes and removing the part of the relevant board situated between the cutting planes. It is hereby possible to bend the sandwich panel in more than one direction, whereby a three-dimensional construction can be obtained with a greater freedom of form. In order to obtain the desired three- dimensional construction the deformation can be carried out such that the deformed board part is curved in the plane of the relevant board and/or that the deformed board part is substantially parallel to the spacer elements in the plane of the relevant board.

When the relevant board is cut through over cutting planes and the part of the relevant board situated between the cutting planes is removed, the spacer elements between the cutting planes can further also be removed so as to reduce the bending stiffness of the relevant board even further and to enable bending of the sandwich panel through an even greater angle. It is then even possible to bend the sandwich panel through an angle in the order of magnitude of 180°, so that the parts of the inner board adjacent to the deformed part come to lie against each other.

After the bending the form of the bent sandwich panel is preferably fixed by fixing the form of the inner board with the relatively small radius of curvature. This can be carried out for instance by mutually connecting the parts of the inner board adjacent to the deformed part, for instance by glueing or welding. Connecting of the parts of the inner board adjacent to the deformed part is preferably carried out by means of a material adhering thereto, for instance a foam material such as polyurethane .

For further stiffening of the three-dimensional construction a stiffening element can be arranged before or after bending in at least one channel located between the spacer elements and the boards. As stiffening element can for instance be used a rod with a cross-section corresponding with the channel and for instance manufactured from steel .

For the sandwich panel is preferably chosen a panel manufactured from polycarbonate or other plastic having corresponding mechanical and physical properties . Polycarbonate can be readily machined, deformed and bent well, while it retains its strength at low and high temperatures .

The present invention further relates to a three-dimensional construction obtained by applying the method according to the present invention. One application for a three-dimensional construction is a housing for a solar energy system as according to claim 14.

The invention will now be further elucidated with reference to the annexed drawings . In the drawings : Figure 1 shows a hollow sandwich panel which is partly deformed according to the method of the present invention,

Figure 2 shows a cross-section of the sandwich panel shown in fig. 1 along line II-II, Figure 3 is a perspective view of a three- dimensional construction obtained by bending the sandwich panel shown in figure 1,

Figure 4 shows in perspective view a three- dimensional construction obtained by applying the method according to the present invention,

Figure 5 is a detail view of the element designated with V in figure 4,

Figure 6 is a detail view of the element designated with VI in figure 4, Figure 7 shows a detail view of the element designated with VII in figure 4, Figure 8 shows another three-dimensional construction obtained by applying the method according to the present invention,

Figure 9 shows a perspective and partly cross- sectional detail view of the three-dimensional construction shown in figure 8,

Figure 10 is a perspective and partly broken- away view of a solar energy system, the housing of which is obtained by applying the method according to the present invention, and

Figure 11 is a detail view of the solar energy system shown in figure 10.

Figure 1 shows a hollow sandwich panel 1. Figure 2 shows a cross-section of this sandwich panel 1. Sandwich panel 1 consists of two parallel boards 2 which are held at a mutual distance by spacer elements 3 extending mutually parallel situated at a mutual distance. The bending stiffness of sandwich panel 1 is reduced in that the rigidity of the upper board 2 as seen in figure 1 is reduced by, deforming a part of this board

2. According to the invention the deformation can be carried out in two ways . In the middle of upper board 2 a part 4 thereof is deformed by this part 4 being heated. By heating sandwich panel 1 on the side of the board 2 for deforming, and preferably cooling the panel on the side of the opposite board 2, a part 4 of the heated board 2 and the spacer elements 3 situated thereunder will be removed from the plane of this board 2 and fuse with the other board 2. On each outer side of sandwich panel 1 a part 5 of upper board 2 is deformed by this board 2 being cut through along cutting planes 6 and the part of board 2 located between cutting planes 6 being removed. The spacer elements lying between cutting planes 6 are also removed.

The deformed board parts 4, 5 form axes of curvature around which sandwich panel 1 can then be bent so as to obtain a three-dimensional construction. The thereby obtained three-dimensional construction is shown in figure 3. By deforming parts of one or both boards 2 in suitable manner, wherein the deformed board parts can be bent and/or parallel to spacer elements 3 in the plane of the relevant board, any desired three-dimensional construction can be obtained.

Figure 4 shows a first embodiment of a three- dimensional construction which can be obtained by applying the method according to the present invention. This is a light-transmitting dormer window wholly manufactured from hollow sandwich panels of transparent material. The dormer window is constructed from different cover elements 7, intermediate elements 8, side elements 9 and mounting elements 10. Each cover element 7 consists of two hollow sandwich panels 11 located at a mutual distance. These sandwich panels 11 are held at a distance by mounting elements 10 arranged on both longitudinal sides of cover element 7. The construction is fitted onto a roof 12 by means of mounting elements 10. Two cover elements 7 at a time are mutually coupled by means of an intermediate element 8 to a length desired for the dormer window. Each intermediate element 8 consists of a curved profile 13 with coupling pieces 14 which are fixed on the ends thereof and which can be pushed into the hollow spaces of mounting elements 10. As shown in figure 4, each curved profile 13 herein comes to lie between the two sandwich panels 1 of the coupled cover elements 7. A side element 9 is arranged on each side of the dormer window. Each side element 9 is coupled to the outermost cover element 7 by means of coupling pieces 15 which are inserted into mounting elements 10. A protruding edge 16 situated on the upper side of side element 9 herein comes to lie between the two sandwich panels 11 of the outermost cover element 7. All couplings between the different elements are preferably glued, so that a good sealing of the whole construction is obtained. Polyurethane is extremely suitable for this purpose since it can absorb thermal expansion of the construction. Figure 5 shows a view of a detail designated with V in figure . Coupling piece 15 is formed from a hollow sandwich panel which is formed according to the method of the present invention. Since parts situated on the inside of the board of the sandwich panel are deformed, the hollow sandwich panel can be folded into the form shown in figure 5 by heating the board or by cutting the board along cutting planes and removing the part of the board situated between the cutting planes. A first part 17 of this coupling piece 15 is pushed into a hollow space 18 of side element 9 and a second part 19 is pushed into a hollow space 20 of mounting element 10 (see also figures 4 and 6) .

Figure 6 shows a view of a detail of the construction designated with VI in figure 4. The mounting element 10 shown in figure 6 is again formed according to the method of the invention. Mounting element 10 contains a hollow space 20 for receiving a coupling piece 10 for coupling a side element 9 and/or for receiving a coupling piece 14 for coupling an intermediate element 8. Mounting element 10 contains a first surface 21 to which the lower sandwich panel 11 of a cover element 7 is fixed, and a second (bent) surface 22 to which the upper sandwich panel 11 of a cover element 7 is fixed (see also figure 4) .

Figure 7 shows a part of the intermediate element 8 shown in figure 3 which is formed by placing a number of hollow sandwich panels one on top of another and glueing them together, wherein stiffening elements 24 are arranged in a number of channels 23 of the sandwich panels.

A large free span can be obtained with the construction shown in figures 4-7.

Figure 8 shows another three-dimensional construction which can be obtained by applying the method according to the present invention. This is a so-called fire window 25 which is arranged in the roof 12 of a building. This fire window 25 is also manufactured entirely from the hollow sandwich panels with application of the method according to the present invention.

Figure 9 shows a partly cross-sectional detail view of fire window 25 shown in figure 8. Fire window 25 is constructed from a number of elements 26 which lie mutually parallel and which can each be folded double in order to open the fire window in the case of fire. Each element 26 comprises two hollow sandwich panels 27 which are held at some mutual distance by spacer elements 28 formed from hollow sandwich panels. According to the method of the invention the bending stiffness of the boards of sandwich panels 27 is reduced in that appropriate parts thereof are deformed, so that it is then possible to bend sandwich panels 27 round the axes of curvature formed by the deformed board parts and to obtain for each element 26 the position indicated with dashed lines in figure 9. For this purpose the upper board of upper sandwich panel 27 is deformed at parts designated with 29, and the upper board of lower sandwich panel 27 is deformed at part 30. The framing 31 of fire window 25 is also manufactured from sandwich panel, as can be seen in figure 9. Between elements 26 on the one side and the outer elements 26 and framing 31 of fire window 25 on the other are provided seals 32 which are arranged in each case between sandwich panels 27.

Figure 10 shows a solar energy system 100 according to the invention in perspective view. This solar energy system 100 has a hollow collector 101 on which the solar radiation is incident and in which a heat transfer medium is arranged. Owing to the incident solar radiation the heat transfer medium in collector 101 will evaporate and rise upward in collector 101 and at the top be urged via pipes 102 through a heat exchanger, where the heat transfer medium once again condenses. The heat exchanger consists of a heat storage tank consisting of elongate elements 103 and elongate flat channel plates 104 which are placed between these elements and through which the heat transfer medium runs . The condensed heat transfer medium flows further from the heat exchanger via pipes 105 to the underside of collector 101.

Solar energy system 100 further has a housing which consists of a transparent upper side 106 formed from a sandwich panel, for instance of polycarbonate, and a tray-like underside 107. Solar energy system 100 is placed with housing 106,107 directly onto roof boarding 108. In order to ensure proper sealing between housing 106,107 and the roof tiles 109 lying on roof boarding

108, the housing 106, 107 further has an apron part 110, which can be adjusted to the form of roof tiles 109 by heating (see also figure 11) . Apron part 110 is coupled slidably to housing 106,107, so that when housing 106, 107 expands due to heating as a result of solar radiation the apron part 110 can displace relative to housing 106,107, whereby cracking is prevented.

In storage tank 103 is stored water which is heated by heat-exchange with the heat transfer medium. In order to prevent heat loss via roof boarding 108, the housing 106,107 is further filled with a composite insulation structure 111 (see figure 11) .

On a part of the elongate elements 103 a heating element 112 can be further arranged which, in the case of a shortage of radiant heat, contributes toward the heating of the water in elongate elements 103.

The following advantages are obtained when three-dimensional constructions are formed according to the method of the present invention. As the embodiments shown in the figures demonstrate, a completely smooth outer surface can be obtained. This is particularly important in dormer windows and solar energy systems in order to ensure good rainwater and waste drainage and to reduce wind noise. Compared to dormer windows and fire windows known from the prior art, roof connections and seals can also be improved in terms of draught, insulating value, the forming and drainage of condensation. The problem which occurs in known light- I-¹ o ⁽ l

Claims

1. Method for forming a three-dimensional construction from a hollow sandwich panel, which consists of two boards which are held at a mutual distance by spacer elements extending mutually parallel and lying at a mutual distance, which method consist of reducing the bending stiffness of the sandwich panel by reducing the stiffness of at least one of the boards, and bending the sandwich panel round an axis of curvature such that in the area of the bending an inner board with relatively small radius of curvature and an outer board with relatively large radius of curvature are created, characterized in that the bending stiffness of at least one of the boards is first reduced by deforming a part of the relevant board, and that the sandwich panel is subsequently bent round the axis of curvature formed by the deformed board part .

2. Method as claimed in claim 1, wherein the deformation is carried out by heating the part of the relevant board.

3. Method as claimed in claim 1 or 2 , wherein the deformation is carried out by cutting through the relevant board along cutting planes and removing the part of the relevant board situated between the cutting planes.

4. Method as claimed in any of the claims 1-3, wherein the deformation is carried out such that the deformed board part is curved in the plane of the relevant board.

5. Method as claimed in any of the claims 1-4, wherein the deformation is carried out such that the deformed board part is substantially parallel to the spacer elements in the plane of the relevant board.

6. Method as claimed in any of the claims 3-5, wherein the spacer elements between the cutting planes are further removed.

7. Method as claimed in any of the foregoing claims, wherein after the bending the form of the bent sandwich panel is fixed by fixing the form of the inner board with the relatively small radius of curvature.

8. Method as claimed in claim 7, wherein the form of the inner board is fixed by mutually connecting the parts thereof adjacent to the deformed part, for instance by glueing or welding.

9. Method as claimed in claim 8, wherein the parts of the inner board adjacent to the deformed part are fixed by a material adhering thereto.

10. Method as claimed in claim 9, wherein a foam material, for instance polyurethane, is used as adhesive material .

11. Method as claimed in any of the foregoing claims, wherein a stiffening element is further arranged in at least one channel located between the spacer elements and the boards.

12. Method as claimed in any of the foregoing claims, wherein for the sandwich panel is chosen a sandwich panel manufactured from polycarbonate or other plastic having corresponding mechanical and physical properties .

13. Three-dimensional construction obtained by applying the method as claimed in any of the foregoing claims .

14. Solar energy system, comprising:

- a housing comprising a part permeable by solar radiation arranged on an upper side;

- a collector which is arranged in the housing and which comprises an inclining space exposed to solar radiation via the permeable part, through which space can flow a heat transfer medium which flows in a first circulation and is coupled to a second medium circuit, wherein the first circulation takes place in a circulation tank which is filled partially with liquid and partially with vapour thereof and which operates as a circulation system which is driven by natural convection of separate evaporation and condensation; - a heat storage tank which is arranged in the second medium circuit and which is thermally coupled to a wall of the circulation tank, close to a part of the first circulation which is directed downward; and - insulation arranged in the housing, characterized in that the housing comprises a three-dimensional construction as claimed in claim 13.