TECHNICAL FIELD

The present invention relates to a construction system at recesses in walls, so called jambs, for the attachment of windows and doors in the wall, which jambs comprise a frame with at least one or more frame pieces, which system comprises a jamb board arranged at at least one frame piece as well as a assembly strip intended for the mounting of the jamb board, which strip is intended to be arranged at the frame, wherein each other facing longitudinal edge portions of the assembly strip and longitudinal edge portions of the jamb board facing the frame as to profile have male and female, respectively, shapes, or vice versa, which match each other.

BACKGROUND

Windows (and doors) which are mounted in walls, especially into outer walls have a considerably smaller thickness than the wall. In order to cover the part of the inner sides of the opening in the wall which is not covered by the window, a so called window jamb is mounted after the mounting of the window. The traditional way is that the carpenter saws a suitable board into four pieces which are attached around the sides of the opening inside the window. The four pieces have to be sawn not only in length but often also in a suitable width alongside so that their width is adapted to the depth of the sides of the opening in the wall which are not covered by the window.

As it is nowadays is avoided (one wants to get a good insulation) to have a wall crossbar together with the window, it is comparatively difficult to fasten the jamb boards. A common solution is to drill a hole in the width of the board and to nail or screw the board through these holes so that it fastens to the window frame. As spacers between the jamb boards and the wall, distance pieces are used against adjacent crossbars through the mounted insulation, wherein thermal bridges are created. Normally, also the lining strips are mounted at the inner side which mask the jamb boards against the inner wall. Thereafter, everything has to be painted so that it becomes neat and the wounds from above all the longitudinal sawings are hidden.

An attempt to a solution of the problem has been presented by the company Moelven. They show a U-strip which is intended to be attached to the frame and in addition a so called F-strip, i.e. a board having a thick and a thin portion running along with the board, wherein the thin portion is intended to be longitudinally sawn so that the jamb board gets an adapted width. Then, the sawn edge has to be inserted into the U-strip at the frame and the thick portion has to be attached to the inside of the wall of the jamb in some way, unclear how. The work mentioned above is rather time-consuming and hence expensive, both as to the carpentry work and the subsequent painting. In addition, the assembly strip is visible from inside the room, which is often regarded as less neat.

There are also other solutions of at least part of the problem, e.g. the one shown in the Swedish patent No. 530 147. In this patent a jamb board is shown which is split and which by means of a wedge-shaped strip is brought to fasten in a groove shaped with inclined walls, which groove has been turned out in the window frame. Thus, an additional component is included here, the wedge-shaped strip, which has to be kept in place in the split jamb board and inside the groove of the window frame during the assembly. One may imagine that the handling of the wedge-strip is delicate and that the deeply split jamb boards are sensitive to pressure and may be broken. To mill the groove in the window frame a special tool is required and therefore that construction is suitable only at new-assembly. However, the problem at the inside of the wall is not solved in this publication.

The object of the present invention is to provide a new and as to work favourable way to attach a jamb board at a frame piece with a window or door frame and which jamb board also has neat and clean surfaces without annoying extra elements.

THE INVENTION AND ITS ADVANTAGES IN DIFFERENT VARIANTS

The above object is achieved with the present invention, which for this purpose in its widest design is characterized by the fact that the above mentioned edge portions of the assembly strip and the portion of the jamb board facing the frame are adapted to each other as to shape so that, after the assembly, said male and female, respectively, portions of the assembly strip and the jamb board together have a self-locking effect, so that the jamb board through this effect is durably kept in its position at the assembly strip and to the frame.

The advantages of the invention described is that, as compared to prior art, one gains working hours in the joinery work through the fact that a quick and simple securing of the jamb board is obtained, which is kept in place by the keeping effect during the remainder of the work to complete the jamb. No supporting steps are needed for the jamb board. In an embodiment of the invention an edge portion of the assembly strip facing away from the window frame is constructed with a tongued portion which is profile adapted to the corresponding groove portion of the edge portion of the jamb board facing against the frame. The groove together with the tongue adapted in size to the groove gives a keeping effect by the surface friction, which implies that one may leave hold of the jamb board, when one has pressed the jamb board in place together with the assembly strip, which jamb board then stays in place and the hands are free for the next step during the assembly of the jamb. In another variant of the construction system, an additional strengthened keeping effect is obtained by the fact that the groove or tongue is provided with longitudinal ridges and the other one of the groove or tongue is provided with longitudinal channels

corresponding to the ridges shape, and that the ridges and channels are located so that the ridges engage the channels in a position where the jamb board is in an assembled final position together with the assembly strip.

In yet another embodiment of the construction system, the edge portion of the jamb board facing the assembly strip is profiled such that, after completed application of the jamb board at the assembly strip, the entire assembly strip is hidden by the jamb board, seen from the inside of the jamb. This implies that no extra working moment is needed during the manufacture of the jamb boards with the desired cross-section profile, as only one tool is required to achieve the entire profile. If the material is wood, this tool is suitably a milling cutter. DESCRIPTION OF FIGURES

The present invention will now be described with reference to the enclosed figures, wherein

Fig. 1 shows a simple, schematically cut view of a common window frame;

Fig. 2 shows a cross-section through a part of a window which has been

provided with a device according to the invention;

Fig. 3 shows a variant of the embodiment of the tongue and groove portions;

and

Figs. 4 and 5 show additionally two variants of the tongue and groove portions.

DESCRIPTION OF EMBODIMENTS

For the sake of definition, a window jamb is shown in Fig. 1 according to a hitherto common construction, wherein 1 refers to a house wall and 2 refers to a window frame. A window cassette has been designated 3. At the inside of the window frame there is window jamb 4. A lining strip 6 is shown at a jamb board 5 included in the window jamb. The lining strips of the other jamb boards have been omitted for the sake of clarity. Thus, the function of the window jamb is in a neat way to frame the part of the opening in the wall which has been cut out for the window and which is not covered by the window frame 2. Here, the jamb boards have been measured and sawn manually and then fitted in place by blocks or other spacers so that they will fit steadily and at a right angle, a time-consuming and delicate work which often requires special solutions. Fig. 2 shows an embodiment of a window jamb according to the invention in a cross- section almost in accordance with the cut I-I through the jamb in Fig. 1. In the figure, a portion of a house wall has been designated 7 and a portion of a window frame has been designated 8, in which frame a window cassette 9 has been mounted. Between the window frame 8 and the wall 7 there is a gap, in which a layer of insulation 10 is normally placed. The window frame 8 is, in a manner known per se, attached to crossbars in the wall 7 by means of frame screws (not shown).

An assembly strip 11 is attached at the window frame. The strip 11 is attached by screws or nails which have been screwed into the window frame through preformed holes in the assembly strip (shown in Figs 5 and 6 in variant embodiments). A glue may also be used, with or without screws/nails. The profile of the assembly strip 11 is such that it has a tongue 12 having a matching correspondence in the form of a groove 13 in a jamb board 14 connected to the strip 11. The tongue and the groove are adapted to each other as to size so that they get a durable connected function through friction at the connection of the jamb board 14 with the assembly strip 11. The jamb board will at the assembly get a final position, when a toe portion 30 reaches and abuts the window frame 8. Therefore, the depth of the groove and the other portions of the jamb board facing the assembly strip 11 are manufactured with such dimensions in relation to the corresponding dimensions of the assembly strip that they do not entirely reach the corresponding portions of the assembly strip at the assembly, but only almost, so that it is the toe portion 30 which reaches a position firmly to the frame and determines the mutual position after the completed assembly. For this reason a thin glue layer may be applied between the surfaces of the assembly strip and the jamb board which meet each other in order to give an additional retaining force. As glue nowadays used often is water-based, a strengthened connecting effect is obtained as the water in the glue gets a swelling effect on the assembly strip, in case it consists of a water-absorbing material, e.g. wood.

Before the assembly, the jamb board 14 is chosen such that its width exceeds the depth of the jamb to be built-in and is then adapted as to width by a longitudinal sawing at its edge potion 21 opposite to the groove, if needed. In this connection, it is arranged that the width-adjusted jamb board is somewhat wider than the depth of the jamb for a reason which will be explained below. A lining strip 22 is arranged at the edge portion 21 opposite to the groove of the jamb board. The lining strip 22 is provided with a longitudinal recess 23, in which the edge portion 21 of the jamb board 14 rests.

Further, the attachment of the jamb board is easy and quick, as it at one edge is put into the assembly strip 11 and at the other edge is put into the lining strip 22, so that it is attached without requiring any spacers or the like through the insulation. The lining strip 22 is easily attached to the inner wall where it screenes the paintwork of the wall, wallpaper or the like. In an embodiment shown in Fig. 3 a tongue 15 of an alternative assembly strip 16 and a groove 17 of an alternatively manufactured jamb board 18 have been provided with longitudinal ridges 19 and channels 20, respectively, so that an alternative self-locking effect is obtained. The height and the depth of the ridges and channels have been exaggerated in order to illustrate the idea.

Fig.4 shows a variant of the combination of tongue/groove, where a tongue 31 and groove 32 are somewhat offset relatively the centre lines of the assembly strip 33 and the jamb board 34, respectively. Here, a screw 35 is shown, which is fastened in the frame 8 through a hole 36 in the assembly strip 33. Depending on the general dimensions of the assembly strip, this variant may give a better space and margins for the location of the screw and hole. One may also use a nail instead of a screw. It is also possible to provide the tongue of the assembly strip with short openings or interruptions with suitable spaces. Holes for mounting screws or nails may be made in these openings for the attachment of the assembly strip to the frame.

Fig. 5 shows a variant, where the tongue 37 is located on the jamb board 40 and a corresponding groove 38 in an assembly strip 41. In this connection mounting screws 35 may be located in predrilled holes 39 at the bottom of the groove. Both in Figs. 5 and 6 it is shown how the toe portion 30 of the jamb board reaches and meets the window frame. With a construction system for window jambs according to the invention described above there are not limitations as to type of windows. The invention may be used together with windows of wood as well of plastics and aluminium. The assembly directs the jamb boards so that the jamb boards principally always obtain an angle of 90° in relation to the plane of the window. It is also possible to combine the jamb system with different types of windowsills for e.g. pot-plants.

The invention is not limited to the examples illustrated in the drawings and in the description but is defined by the claims included in the application. For instance, the invention may be used on a jamb at the outside as well as at the inside. The window may also be of an openable type with associated frame. Further, the profiling of the tongue and groove portions of the assembly strip and the jamb board, respectively, may be varied. The important thing is that a durable connecting effect is achieved when both have been connected in the final position, i.e. are finally assembled.