Window constructions particularly incorporating curved parts have always been popular with designers. In practice, it has been difficult to use conventional technology to manufacture window constructions with shapes differing from the rectangular and their durability has been poor. This is mainly due to the multi-component construction and the natural shrinkage and swelling of the timber, which finally results in the entire window construction breaking. In addition, in the prior art, the outer frame, to which the window casement incorporating the glazing is fitted, is made first. When the window construction in question is installed in an opening formed in a structure, such as a wall, the outer frame is fitted first and the casements last. In this stage, installation errors are common and the components are often insufficiently sealed.

Attempts have been made to avoid the drawbacks caused by the shrinkage and swelling of timber, for example, by using plastic as the manufacturing material. However, the thermal expansion of plastic is so great that suitable applications are limited by the need to avoid the glass being broken. In addition, the plastic components are difficult to manufacture and their attachment to each other is problematic. In addition, there are

only a few alternative surface treatments for a plastic material. It is also difficult to fit the window constructions into openings of differing depths, the final result being at the very least some kind of compromise. Aluminium profile has also been used as the material, but forming the profile into a desired shape is both limited and difficult. At the same time, the manufacturing costs of the window construction become great.

US patent 5007219 discloses a curved window construction, in which the glazing unit is secured by support pieces on both sides. Plastic, flexible frames that surround the entire circumference of the glazing unit are used in the manufacture.

A sufficient number of support pieces, some of which are attached with screws and some by shape-locking, are then attached to the frames, on both sides of the glazing unit. In addition to this, the window construction includes nailing strips to be attached to the frames, with the aid of which the window construction is attached to the opening.

The disclosed window construction is formed of numerous components, which are attached individually to each other. In addition, there are no seals between the components. Further, the procedure in question can be used to manufacture window constructions that incorporate only partly curved window units.

The attachment of the numerous components to each other can also lead to installation errors, while the window construction requires a large opening, or at least wide, separate cover strips to cover the nailing strips. In addition, further glazing units cannot be added to the disclosed window construc- tion. In other words, the depth of the window construction is always constant. In general, the aforesaid window construction is difficult to manufacture and install. In addition, it has a limited number of alternative shapes while it is impossible to seal it adequately, which limits the applications of the window construction.

US patent number 5265388 discloses a window construction, which is formed of two frames and one glazing unit. The frames, which incorporate include flange components, are moulded plastic pieces, between which the glazing unit is pressed. By machining the frame, the depth dimension of the window construction can be adjusted slightly, but this is a question of only a few tens of millimetres. In addition, the disclosed window construction is almost entirely unsealed. It is also impossible to use more than a single glazing unit. Further, there are few alternative surface treatments for plastic material and the weatherproofing of the plastic is insufficient for outdoor use. In addition, screws are used to attach the frames to the wall structure.

The invention is intended to create a new type of window construction, which is more durable and versatile than previ- ously, and which can be applied in structures of different thicknesses. In addition, the invention is intended to create a new type of method for manufacturing the window construction, which is simpler and easier than previously. The characteristic features of the window construction according to the present invention are stated in the accompanying Claim 1. Correspond- ingly, the characteristic features of the method according to the invention are stated in the accompanying Claim 13. In the window construction according to the invention, the various components are attached to each other precisely and tightly.

The window construction is suitable for use even in demanding conditions, as the sealing between the components is tight and there is little natural shrinkage and swelling in the compo- nents. Further, the window construction can be easily fitted to openings of different depths, by changing the positions and number of the components. Despite its versatility, the window construction has only a few different types of component and these additionally incorporate various alternative properties.

The surface treatment of the window construction is also more diverse than previously while the finished surface treatment will last in use for a long time, thanks to the lack of the

natural shrinkage and swelling of the components. The window construction can be ready assembled prior to installation and easily and securely fitted while leaving the structure un- touched.

In the following, the invention is examined in greater detail with reference to the accompanying drawings showing some embodiments of the invention, in which Figure 1 shows a partial cross-section of the window con- struction according to the invention fitted to an opening arranged in a structure, Figure 2a shows a half front and a half rear view of a first embodiment of the support piece of the window construction according to the invention, Figure 2b shows cross-sections of the support piece of Figure 2a, at levels C-C, B-B, A-A, and F-F, Figure 2c shows a cross-section of part of the window con- struction according to the invention formed from support pieces according to Figure 2a, Figure 3a shows a half front and a half rear view of a second embodiment of the support piece of the window construction according to the invention, Figure 3bjlshows cross-sections of the support piece of Figure 3a, at levels C-C, B-B, A-A, and F-F, Figure 3c shows a cross-section of part of the window con- struction according to the invention formed from support pieces according to Figure 3a, Figure 4 shows a schematic cross-section of part of the window construction according to the invention fitted to an opening arranged in a structure, Figure 5 shows a half front and a half rear view, as well as a cross-section at the level M-M, of the end piece of the window construction according to the inven- tion,

Figure 6 shows a partial cross-section of a second embodiment of the window construction according to the inven- tion, fitted to an opening arranged in a structure.

Figure 1 shows the window construction according to the invention, which is intended to be installed in an opening 11 arranged in a structure 10. The structure is usually an interior partition or an external wall, in which a window is desired. The window construction also includes at least one glazing unit, which is this embodiment comprises two sheets of glass sealed to each other. Figure 1 shows a window construc- tion, in which there are two glazing units 12. In other words, there are four consecutive sheets of glass in the window construction. Other embodiments of the window construction according to the invention are shown in Figures 2c, 3c, and 6.

Generally, the window construction also includes support pieces on either side of the glazing unit, which entirely surround the glazing unit. Thus, the window unit is fully supported on both sides. The ready window construction is finally fitted to the opening, which will be described in greater detail later.

There is one continuous support piece, which entirely surrounds the glazing unit, on each side of the glazing unit. In other words, on each side of each glazing unit there is, surpris- ingly, only one support piece, which in addition is completely continuous, with no joints over either its depth or its radius.

Thus, the window construction is simpler, more durable, and better sealed than previously. In addition, it is easier to form the window construction, which can also be more diverse.

Figure 2a shows a half front and a half rear view of a first embodiment of the support piece 13 according to the invention.

Correspondingly, Figure 2b shows a cross-section of the support piece 13 of Figure 2a. Further, the support pieces are attached directly to each other by means of axial fasteners, the glazing unit being pressed between the support pieces. Thus, by using simple fasteners, a window construction is created, which it is

surprisingly easy to fit into the aforesaid opening. In addition, the glazing unit is better supported than previously and it is easy to seal, as will be described in greater detail later.

According to Figure 2c, the window construction according to the invention can be easily manufactured. At its simplest, support pieces 13 according to the invention, which are tightened against each other, are installed on either side of a glazing unit 12, which is, as such, known. In the support piece 13 of Figure 2c, there is, in addition, a curved protru- sion 15, which extends the outermost part of the support piece 13. Thanks to the protrusion 15 and shoulder 16 thus formed, it is easy to install and centre the glazing unit 12. In addition, it is easy and simple to install such a window construction in an opening arranged, for example, in a wall. However, openings have different depths, so that in practice it is necessary to manufacture window constructions of different lengths. The window construction according to the invention further surpris- ingly includes one or more support pieces to be attached to the previous support piece, in order to adjust the axial length of the window construction as desired. Thus, the axial length of the window construction can be increased as desired, according to Figure 1. Such a support piece 13'is shown in a half front and a half rear view in Figure 3a. Correspondingly, Figure 3b shows cross-sections of the support piece 13'of Figure 3a. The support pieces according to the invention are thus used both to support the glazing unit and to increase the total axial length of the window construction. The support piece 13'of Figure 3c lacks the aforesaid protrusion, but despite this the glazing unit 12 can be firmly installed between the support pieces 13', according to Figures 1,3c, and 6. In practice, when commencing manufacture, the depth of the opening is first measured, on the basis of which the necessary number of support pieces, window units, and seals are attached to each other, to form a single

package. The package is next fitted to the opening in the structure.

In principle, after this, the window construction according to the invention described above could then be fitted to the opening conventionally, for example, using wedges. However, the window construction according to the invention further includes an end piece, with greater outer dimensions than the support piece, which is intended to be attached to the outer support piece, in order to secure the window construction in the opening. This is shown particularly in Figures 1 and 6. In practice, the pre-assembled window construction is fitted by using two end pieces to press on each side of the structure incorporating the opening. In other words, the end pieces are used to press the window construction into its final position.

If necessary, polyurethane foam, for example, can be injected between the window construction and the opening, in order to seal the installation. However, the actual fitting takes place simply and cleanly by means of the aforesaid end pieces. This also eliminates the need for separate cover strips. On the other hand, the end pieces can be easily replaced later by others of, for example, a different colour, so that the window construction can be made to suit the rest of the interior decoration. End pieces of different colours and with different properties can also be used in one and the same window con- struction.

The support pieces according to the invention are attached to each other by means of axial fasteners. A handy way of attach- ment is achieved by means of axial through-holes, of which there is preferably an even number, arranged for the fasteners at regular intervals in the support piece. In addition to this, some of the through-holes have a smaller diameter than that of the fastener, in order to form an attachment grip for the fastener. This permits the use of simple fasteners, while the support pieces can always be attached to each other suffi-

ciently firmly and evenly. In the embodiment described, there are twelve through-holes 18 and 18'in a single support piece, half of which are the smaller through-holes 18'described above, according to Figures 2a and 3a. Thus, consecutive support pieces can be attached to each other, using alternately different through-holes, as required. One such connection is shown in Figure 1, in which the head of a conventional screw fits into a large through-hole while the actual screw thread attaches itself to a small through-hole in the next support piece. In addition, in the embodiment shown, the support piece can be rotated around its centre, as well as be turned around completely, in order to achieve a suitable attachment grip.

In order to permit the aforesaid rotation and turning, accord- ing to the invention at least one support piece or end piece is an annular, coaxial, injection-moulded piece. In addition, the support piece is preferably symmetrical. The piece being coaxial is an advantage when attaching the components to each other. In addition, symmetry will assist when planning the through-holes and when manufacturing the window construction.

Thus, axial ventilation holes, which are fitted next to each other or offset from each other in adjacent support pieces in order to adjust the ventilation effect, are also arranged in the support pieces. In that case, the ventilation holes in the symmetrical support pieces can be fitted next to each other.

The entire window construction will then be thoroughly venti- lated. This is shown in the window construction of Figure 2c, in which air is able to circulate from the outer support piece through the next support piece between the glazing units. Thus the entire window construction is thoroughly ventilated.

Alternatively, by rotating the consecutive support pieces by, for example, 90° to each other, the ventilation holes are offset from each other. The ventilation is then prevented. In addition, by placing seals in grooves arranged in the support pieces or between the support pieces, the window construction can be fully hermetically sealed if necessary. Thus the window

construction according to the invention is suitable for use even in bathrooms and in boats. Besides sealing, the seals also attenuate vibration.

In the window construction disclosed, there are two types of seal 20 and 21. The first are 0-ring seals, for which there are suitable grooves in the support pieces. An O-ring seal is reliable and it has no effect on the overall dimension of the window construction. The second seals 21 are thicker and they are used to fill, for example, the gap remaining at the glazing unit. In the thick seals, there are also corresponding holes next to the ventilation holes, in order to permit ventilation (not shown). The 0-ring seals are of, for instance, rubber while the thick seals are of porous polyethylene foam plastic.

Figure 2c also shows filter pieces 23, which are installed in a recess 24 arranged at the ventilation holes 19. Thus, the air travels through several filter pieces, while nevertheless ventilating the window construction. It is also possible to use a wide, continuous filter ring 26 between two consecutive support pieces, according to Figures 1 and 2c.

Figure 6 shows a second embodiment of the window construction according to the invention. In this case, the glazing unit 12 comprises a single sheet of glass, which is pressed between two support pieces 13'. The minimum thickness of the construction is then about 25 mm. For a thicker construction than this, one or more additional support pieces are added to the window construction and the end pieces are finally installed. In addition, it is possible to use various kinds of glazing unit, to create, for example, bullet-proof or sound-insulating windows.

The window construction according to the invention is thus fitted to an opening with the aid of the end pieces. In addition, the end piece 17 includes flange components 17' (Figures 1 and 6) that are larger than the opening 11. Accord-

ing to the invention, at least one additional end piece is fitted partly coaxially to overlap relative to the support piece, in order to create an axial adjustment tolerance. This is shown in Figure 4, in which six screws are used to attach the end piece 17 simply but firmly to the outer support piece 13'. The other components of the window construction are not shown here. Alternatively, suitable quick-release fasteners can be used between the end piece and the outer support piece, making the screws unnecessary. In Figure 5, the end piece 17 is shown in a half front and a half rear view. The same figure also shows a cross-section of one end piece 17. According to the invention, the adjustment tolerance of one end piece or the total adjustment tolerance of the end pieces is at least as great as the effective axial thickness of one support piece.

Thus the window construction according to the invention can be used to cover all openings of different depths, by simply adding support pieces when required. In the embodiment shown, the thickness of the support piece is 24 mm and the adjustment tolerance s in both end pieces is about 17 mm. In addition, the glazing unit has a diameter of about 200 mm and the end pieces an external diameter of about 280 mm. A sufficient adjustment tolerance is ensured by the dimensioning of the groove in the support pieces and of the end piece. In addition, the mutual fitting between the end piece and the support piece permits an error in the axial direction. Thus, even if the walls of the structure are not strictly parallel, the end piece will always settle parallel to the wall. In addition, the stiffening ribs 26 of the end piece have openings 27, so that a labyrinth is formed (Figure 5). Thus, moisture that may condense inside the end piece flows out of the window construction in a controlled manner. The stiffening ribs 26 also press the seal 21 tightly against the edges of the opening, so that excellent sealing is achieved without puttying.

Thanks to the support pieces described above, conventional screws can be used as the fasteners. The support pieces next to

the glazing unit can, however, be attached to each other using pairs of nuts and bolts 25, according to Figure 2c. The small through-holes referred to above in the outer support pieces are left free for attaching the next support pieces. The depth of the window construction can therefore be increased in both directions. Corresponding cross-sections of the support pieces are shown in Figures 2b and 3b. In addition, the large through- holes are at least partly shaped in such a way that the nut will lock into them. This facilitates the assembly of the window construction.

The versatile and adaptable window construction according to the invention permits the use of completely continuous and dimensionally precise components. Such a component is created particularly by the injection moulding method and by using composite plastic materials. The introduction of the method requiring moulds is facilitated by the small number of differ- ent components. At its simplest, only one kind of support piece and one kind of end piece are required. According to the invention, in a composite plastic material the ratio of the binder to the filler is about 1: 1. The filler is wood fibre and the binder, for example, a thermosetting plastic. Tests have been made with a material in which the binder is polypropylene (60 %) and the filler wood pulp (40 %). Such a material can be easily injection moulded and does not shirk or swell much, but is highly durable. The tensile strength of the material is at present on the same level as untreated timber in the direction of the grain, but as much as ten times greater in the trans- verse direction. In addition, the pieces can be surfaced treated, or even surfaced, in numerous ways. Thus, if desired, even a plastic material can, for instance, be made to look like genuine wood. Other mouldable materials are also possible.

As a material, a thermosetting plastic natural fibre composite of this kind will not split, but is strong and will neither swell nor rot. In addition, as the material is non-toxic it can

also be recycled. Nevertheless, it is a weather-resistant material, from which dimensionally-precise products can be manufactured. In addition, the material is a good thermal and acoustic insulator. The material is manufactured by fiberizing timber or fibrous plants to create cellulose fibres and at the same time separating the lignin, which can be used, for example, as energy for the manufacturing process. The fibres and the thermosetting plastic are added to each other and the material is granulated. The granulate can be moulded using existing plastic moulding equipment directly into the shape of the end product, with a very small waste percentage.

The products can be easily recycled. The products can be ground and remoulded, or exploited as energy in combustion. In addition, the properties of the material, such as density, colour, and elasticity, as well as water absorption and surface friction can be varied within quite wide limits. The material, which can be solid-coloured, can even be used to make hollow profiles. In addition, the various components can be combined by welding. Thus, it is possible manufacture wood-like products in entirely different ways.

Instead of the round embodiment described, other, preferably symmetrical shapes can also be implemented in the manner according to the invention. These include, for example, ellipses, ovals, parallelograms, and even rectangles. The external appearance of the window construction can also be altered by simply replacing the end piece with one of a different shape. Despite the shape, the basic idea of using continuous pieces remains. In addition to this, the depth of the window construction can be increased simply while it is extremely easy to fit the window construction into the opening.

Further, the window construction can be made either completely airtight or breathing. Thus, the window construction can be used in very different and demanding conditions, such as in saunas and ships.