Title of Invention

External screening arrangement with a set of lamellas.

Technical Field The invention relates to an external screening arrangement according to the preamble of claim 1. The invention furthermore relates to a method for manufacturing a screening body for such a screening arrangement.

Background Art Screening arrangements positioned in front of windows to cover the window from direct sunlight in the screening position are common. Such screening arrangements are typically either positioned on the interior or the exterior side of the window opening to be screened. Internal screening arrangements include roller blinds, Venetian blinds, pleated blinds etc. and are typically relatively easy to install, as the installation site is normally immediately accessible by the person carrying out the installation and the entire operation may be carried from the inside of the building in which the window is installed. External screening arrangements, on the other hand, are from the outset made from materials being sturdier and heavier than internal screening arrangements, and the installation site involves building parts located on the exterior side of the building. Screening arrangements also must fulfil different requirements depending on whether they are installed in a fagade window, i.e. in a substantially vertical position, or in an inclined or even horizontal surface such as a roof. Not only are screening arrangements for roof windows configured to take into account the effects of gravity due to the resulting force being out of the general plane of the roof window, but the mounted position itself, on a roof, puts large demands to the components of the external screening arrangement. One example of a particularly robust and well-functioning external screening arrangement is a roller shutter which provide a high degree of protection of the subjacent roof window and the room of the building in which the roof window is installed, including protection against light, sound and unwarranted entry such as burglary. In roller shutters, the screening body is composed of a large number of lamellas which are typically hinged together to form a substantially flat panzer. The provision of such a sturdy layer is not only cumbersome, expensive, and heavy, but also requires sufficient available space in the top casing, since the top casing must accommodate the screening body in the non screening position.

Summary of Invention

With this background, it is therefore an object of the invention to provide a screening arrangement, which can give satisfactory protection of a roof window while at the same time being cost-effective to manufacture.

In a first aspect of the invention, this and further objects are achieved by a screening arrangement of the kind mentioned in the introduction, which is furthermore characterised in that the screening arrangement further comprises: each lamella of the set of lamellas comprises a top element positioned on a first side of the screening cloth and a bottom element positioned on a second, opposite side of the screening cloth, that the top element and the bottom element are held together by means of a mechanical connection, sandwiching the screening cloth between them, and that two adjacent lamellas of said set of lamellas are positioned at a distance from each other, in the longitudinal direction of the screening body, exceeding the lamella length.

In this way, full flexibility in the design and configuration of the lamellas on the screening cloth is achieved. Since each lamella is formed simply by sandwiching the screening cloth between the top and bottom element, the lamella may be formed anywhere on the screening cloth independent of other lamellas, allowing for the lamella to only be placed where it is needed, possibly reducing the weight of the screening body by rendering the need for additional lamellas redundant. In comparison to regular roller shutters, the weight impact by the lamellas is reduced to a substantial extent. By the term “mechanical connection” within the context of the present invention is to be understood as a releasable connection without the use of adhesion in the form of glue or bonding between the top and bottom element and the screening cloth. No additional fastening means or penetration of the cloth are foreseen. That is, the mechanical connection encompasses any non-cloth-penetrating, non-adhesive connection means allowing the top element and the bottom element to maintain their respective positions relative to the cloth. This may also include press fitting the top and bottom elements with the cloth sandwiched between them. Not least from an environmental point of view, this solution is desirable as sustainable and fulfilling the requirements to circularity in the use of materials, as the screening cloth will remain substantially intact. The flexibility in the number and position of the lamellas is also advantageous from a manufacturing and storage perspective, since the screening body may be tailor-made according to specifications by simply selecting the number, shape and mutual distance between lamellas.

The external screening arrangement may be an external flat roof window screening arrangement and/or an external inclined roof window screening arrangement. The external screening arrangement may preferably be configured for being mounted on a roof window in an inclined roof and/or a flat roof. In an embodiment the external screening arrangement is in a mounted condition mounted on a roof window, wherein said roof window is mounted in an inclined roof or a flat roof.

In a presently preferred embodiment, the screening cloth is a coherent piece of cloth extending throughout the predefined length between the first end portion and the second end portion. This provides for a particularly easy and resource-efficient manufacture, since only a single piece of cloth needs to be handled.

The number of lamellas, mutual distance between adjacent lamellas and length of the lamellas may be chosen arbitrarily in order to enhance the flexibility in the manufacturing of the screening arrangement, typically in dependence of the overall size of the screening arrangement.

It is presently preferred that said set of lamellas of the screening body comprises 2 to 6 lamellas, preferably 3 to 5 lamellas. This provides for the desired properties in a wide range of screening arrangement sizes.

The distance between adjacent lamellas preferably exceeds the lamella length by a factor of 1 .1 to 10, preferably 2 to 8, more preferably 4 to 6. In this way, more than half of the screening body is free of lamellas, thus providing for a pleasant appearance and appropriate weight reduction. It is presently preferred that the distance between adjacent lamellas is substantially equidistant and lies in the range 50 to 400 mm, preferably around 200 to 300 mm. This range has proven advantages during manufacture and renders a particularly harmonic appearance

Advantageously, the lamella length may lie in the range 30 to 50 mm, preferably about 40 mm, This provides for an excellent performance during manufacture and in use.

The configuration of the top and bottom element may in principle be chosen arbitrarily, as long as a safe connection to the screening cloth is ascertained. In presently preferred embodiments, various configurations provide for excellent strength and connection properties, and furthermore facilitate the manufacturing.

In a second aspect of the invention, the invention relates to a method for manufacturing a screening body with a set of lamellas comprising at least one lamella for a screening arrangement is provided

Other presently preferred embodiments and further advantages will be apparent from the subsequent detailed description and drawings.

A feature described in relation to one of the aspect may also be incorporated in the other aspect, and the advantage of the feature is applicable to all aspects in which it is incorporated.

Brief Description of Drawings

For exemplifying purposes, the invention will be described in closer detail in the following with reference to embodiments thereof illustrated in the attached drawings, wherein:

Fig. 1a is a perspective view of a screening arrangement in an embodiment of the invention, with the screening body in an unwound, screening position;

Fig. 1b is a view corresponding to Fig. 1a, with the screening body in a wound-up, non-screening position;

Fig. 2a is a perspective view of a roof window with a screening arrangement in another embodiment of the invention;

Fig. 2b is a perspective view of a roof window with a prior art screening arrangement;

Figs 3a and 3b are simplistic perspective views of the operational principles of a cord system, with a screening body in an unwound screening position;

Fig. 4a is a partial perspective, sectional view, on a larger scale, of the upper left-hand corner of the external screening arrangement in an embodiment of the invention;

Fig. 4b is a partial perspective view of details of the external screening arrangement of Fig. 4a;

Fig. 5 is a perspective longitudinal sectional view partial perspective, sectional view of the screening arrangement in an embodiment of the invention;

Fig. 6 is a partial perspective sectional view of the upper left-hand corner of a screening arrangement in an embodiment of the invention; Fig. 7 is a partial perspective, exploded sectional view of the lower left- hand corner of a screening arrangement in an embodiment of the invention;

Figs 8a and 8b show a partial perspective and a partial perspective, exploded view, respectively, of the detail VIII in Fig. 5;

Figs 9a and 9b show a schematic exploded end view an and end view, respectively, of steps in an example of a manufacturing process of a lamella of the screening arrangement in an embodiment of the invention;

Fig. 10 is an end view, on a larger scale, of a lamella in another embodiment of the screening arrangement according to the invention;

Fig. 11 is an end view of a roller shaft and the lamella of Fig. 10; and Fig. 12 is a sectional view of the top casing with roller shaft and screening body in an embodiment of the screening arrangement according to the invention. Description of Embodiments

In the following detailed description, preferred embodiments of the present invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. It may also be noted that, for the sake of clarity, the dimensions of certain components illustrated in the drawings may differ from the corresponding dimensions in real-life implementations. It is noted that terms such as “up”, “down”, “left-hand”, “right-hand”,

“exterior”, “interior”, “outer”, “inner” are relative and refers to the viewpoint in question.

Figs 1a and 1b Referring initially to Fig. 1a and Fig. 1b, where perspective views of a screening arrangement 1 in an embodiment of the invention are shown, it is seen how the screening arrangement 1 comprises a screening body 11, a top casing 23 and a bottom profile 15.

The screening arrangement 1 is configured to be mounted on a roof window 2 (see Fig. 2a) to assume a mounted condition, in which the screening body 11 is movable in a general longitudinal direction between a non-screening position and a number of non-screening positions in which the screening body 11 at least partially covers an opening of the roof window 2.

The screening arrangement 1 further comprises a roller shaft 14 (Figs 3a and 3b) accommodated in the top casing 23 and connected to drive means, the drive means being configured to rotate the roller shaft 14 in a winding direction W1 and an unwinding direction W2 (see Figs 3a and 3b).

The screening body 11 has two side edges and a predefined length between a first end portion and a second end portion. The first end portion is connected to the roller shaft 14 accommodated in the top casing 23 such that the screening body 11 may be wound on the roller shaft 14 in the non-screening position. The second end portion is connected to a bottom profile 15. Furthermore, the screening arrangement comprises two side rails 21 , 22, a first side rail 21 and a second side rail 22 to guide at least opposing ends of the bottom profile 15. In some embodiments, also the side edges of the screening body 11 may be guided in the side rails 21 , 22. The term “ends” of the bottom profile 15 is to be construed to encompass any structure of the bottom profile 15 suitable to interact with the side rails 21 , 22, including separate elements and one-piece configurations.

In Fig. 1a, the screening body 11 is shown in an unwound screening position, and in Fig. 1 b the screening body is shown in a non-screening position, in which the screening body 11 is wound and stored on the roller shaft 14 in the top casing 23. In the non-screening position, the bottom profile 15 may either be completely accommodated within the top casing 23, or protrude slightly therefrom.

Fig. 2a

The screening arrangement 1 is configured to be mounted on the exterior side of the roof window 2, which in turn is typically mounted in an inclined roof surface (not shown). The roof window 2 has a frame structure 3 and a sash structure 4. The frame structure 3 is configured to extend in parallel to the roof surface, while the sash structure 4 is configured to be opened to a variety of positions, for instance as shown in Fig. 2a. The frame structure 3 and the sash structure 4 each has a top member 3a, 4a and a bottom member 3d, 4d and two mutually parallel side members 3b, 3c, 4b, 4c. The sash structure 4 is pivotally connected to the frame structure 3 via hinges 5, in the shown embodiment here at a substantially central hinge axis, however other positions of the hinge axis are conceivable as well. Also visible in Fig. 2a is a pane 7 encased in the sash structure 4.

In order to allow the screening arrangement 1 to follow the movement of the sash structure 4 during opening of the roof window 2, the side rails 21 , 22 are connected to the sash structure 4 in a slidable and rotatable connection at or near the bottom of the sash structure 4. The top casing 23 may either be rotatably or fixedly connected to the roof window 2, at or near the top of the frame structure 3. The connection between the top casing 23 and the side rails 21 , 22 is either fixed, i.e. the side rails 21 , 22 are rigidly connected to the top casing, or rotatable, i.e. there is a hinge connection (not shown) between the top casing 23 and the side rails 21 , 22. Examples of a roof window with a prior art screening arrangement are shown in the embodiments of applications EP 3 015637 A1 and EP 2 390455 A1 .

In Fig. 2a, a fitting 6 is generally designated to indicate the slidable and rotatable connection between the bottom corners of the sash structure 4, defined by the bottom sash member 4d and the side sash members 4c, 4b, to the first side rail 21 and the second side rail 22, respectively. The fittings 6 allow for the sash structure 3 to be guided along the side rails 21 , 22 when the sash structure 4 is pivoted about its hinge axis when opening the roof window 2.

In the embodiment of Fig. 2a, the top casing 23 comprises a slightly curved cover portion 232 and an end portion 233 at each of the longitudinal ends of the top casing 23. Furthermore, a solar panel 231 is placed in the top casing 23 which could be used to power the screening arrangement 1 , possibly connected to a battery inside the top casing 23; however, power may also be provided from a main housing supply. Wiring, motor control and power means for the motor are not shown. The top casing 23 is rotatably connected to the frame structure 3 of the roof window 2 with a top casing hinge 234. The side rails 21 , 22 are, at respective first fixed ends, rigidly, i.e. fixedly connected to the top casing 23 such that the side rails 21 , 22 may pivot out of the plane defined by the roof surface and the frame structure 3 when opening the sash structure 4.

Fig. 2b

In Fig. 2b, a prior art screening arrangement is shown. Elements having the same or analogous function as in the embodiments of the invention are denoted by the same reference numerals for convenience. In this prior art screening arrangement 1 , the top casing 23 is fixedly connected to the top frame member 3a, and the side rails 21 , 22 are rotatably connected to the top casing 23. The movement of the side rails 21 , 22 is limited by the presence of a stay 8 connected to a respective side cover 30’ which in turn is connected to the side member 3c of the frame structure 3 of the roof window 2. A corresponding side cover is connected to the opposite side member 3b. The side covers 30’ provide general protection of the other components of the screening arrangement 1 and contributes to the shielding of the opening of the roof window 2.

Figs 3a and 3b

Referring now to Figs 3a and 3b, which show the operating principle and possible configurations of a cord system of embodiments of the screening arrangement 1 of the invention, two guidance cords 12 are provided to ensure parallel guidance of the bottom profile 15 during operation of the screening arrangement 1 .

Each guidance cord 12 is, at one end, connected to a respective winding device including a winding reel 16, and, at another end, connected to a tensioning device generally designated 13 in the bottom profile 15. The configuration of such winding reels are well-known as such, one example being found in the embodiment of Applicant’s WO 2006/074653 A1. It is noted that the term “in the bottom profile” should be interpreted in its broadest sense, thus including positions at or near a wall of the bottom profile, such as for instance behind a front wall of an open profile.

The guidance cords 12 are wound on the winding device oppositely relative to how the screening body 11 is wound on the roller shaft 14, i.e. when the roller shaft 14 rotates in the winding direction W1 , the screening body 11 is wound, while the guidance cords 12 are unwound, and vice versa when the roller shaft 14 rotates in the unwinding direction W2. The winding device including the winding reel 16 and the roller shaft 14 are both accommodated in the top casing 23.

In principle, the winding reels 16 should unwind/wind a length of guidance cord 12 substantially equal to the length of screening body 11 wound/unwound by the roller shaft 14 when the bottom profile 15 is moved in the general longitudinal direction of the screening arrangement 1 as defined by the screening body 11 and the side rails 21 , 22. However, due to variations in the effective diameter of the roller shaft 14 caused by successive windings of the screening body 11 in dependence on the amount of screening body 11 wound on the roller shaft 14, the guidance cords 12 are slackened, thereby impairing the parallel guiding function. To compensate for slack in the guidance cords 12, the tensioning device 13 provides a tension on the guidance cords 12 such that during operation, variations in the required length of the guidance cords 12 is accommodated for.

In the configuration shown in Fig. 3a, the winding reel 16 is arranged at one end of the roller shaft 14. The winding reel 16 can however, also be arranged inside the roller shaft 14 as shown in Fig. 3b, such that the roller shaft 14 and thus also the screening body 11 may be made wider, or two winding reels, one at the respective end of the roller shaft 14.

Also visible in the general overviews of Figs 3a and 3b are return elements 10 for guiding the respective guidance cord 12 from the winding reel 16 around the associated return element 10 and up to and into the bottom profile 15, and further to the tensioning device 13. Since the return element 10 is located at or near the free end of the respective side rail 21 , 22, this means that the returning or upwards directed part of the guidance cord 12 runs alongside the downwards directed part of the guidance cord 12 from the winding reel 16 to the return element 10. The upwards directed part of the guidance cord 12 may run in the same track of the respective side rail 21 , 22 as the downwards directed part of the guidance cord 12. In the embodiment shown in one and the same track 221 (cf. Figures of specific embodiments) of the side rail 22.

Figs 4a and 4b

Details of the top casing 23 in the embodiment shown are shown in Figs 4a and 4b. The first end portion of the screening body 11 is connected to the roller shaft 14 accommodated in the top casing 23. At the end of the roller shaft 14, the winding device including a winding reel 16 is provided. A similar winding device may be provided at the opposite end of the roller shaft 14. In a manner known per se, the winding reel 16 serves to receive the guidance cord 12 forming part of the cord system to serve as a parallel guidance assembly of the screening arrangement in order to keep the bottom profile 15 substantially parallel to the top casing 23 throughout operation.

Figs 5 to 12

Referring initially to Fig. 5, and also to Fig. 2a, the screening body 11 comprises a screening cloth 110 and a set of lamellas 10 including a plurality of lamellas 10. In the embodiment shown, three lamellas 111 are provided. As described in the above, the screening body 11 has a predefined width extending between the two side edges and a predefined length between a first end portion and a second end portion.

The screening cloth 110 has such dimensions such as to correspond in substance to the dimensions of the screening body 11 in total. In the embodiment shown, the screening cloth 110 is a coherent piece of cloth extending throughout the predefined length between the first end portion and second end portion of the screening body 11 , but other configurations involving two or more cloth sections having different properties. The material of the screening cloth 110 may in principle be chosen in any suitable way fulfilling the requirements to a screening body in an external screening arrangement in a roof window. Such requirements include wear resistance, UV resistance etc. It is desirable to form the screening cloth from a pliable material, which may furthermore have black-out properties, and may be reinforced by glass-fibre.

The lamellas 111 extend substantially from one side edge to the other of the screening body 11 . A lamella length L111 is defined in the longitudinal direction of the screening body 11 as will be described in further detail below. In the shown embodiment the screening body 11 comprises three lamellas 10.

According to the invention, two adjacent lamellas 111 are positioned at a distance A, B from each other in the longitudinal direction such that the distance A, B exceeds the lamella length L111 . The first distance A is a distance between the two lamellas closest to the second end portion of the screening cloth 110, when the screening body 11 is in the unwound position. The second distance B, being a distance between the two lamellas closest to the first end portion of the screening cloth 110 and thus of the bottom profile 15, when the screening body 11 is in the unwound position. The first distance A and the second distance B may be equivalent. The first distance A and the second distance B may also differ. In the case of more than three lamellas 11 , the distances between lamellas may be equivalent, differ or some distances between lamellas may be equivalent, while other distances differ, e.g. if the screening body comprises four lamellas, distances between three of the lamellas may be equivalent while the distance of the fourth lamella to the other lamellas may differ.

Depending on the overall dimensions of the roof window and the screening arrangement and of the desired expression to be achieved by the screening body 11 , the screening body 11 may comprise any number of lamellas. Typically, 2 to 6 lamellas are provided for regular sizes roof windows, preferably 3 to 5. The distance A, B between adjacent lamellas 111 typically exceeds the lamella length L111 by a factor of about 5, but ranges including 1 .1 to 10, preferably 2 to 8, are conceivable. The actual lamella length L111 is here about 43 mm and typically lies in the range 30 to 50 mm. As a consequence, the ensuing distance A, B between adjacent lamellas 111 lies in the range about 250 mm but may be anything between 50 and 400 mm, preferably 200 to 300 mm. The distances A, B between lamellas 111 may also be chosen for structural purposes, to assure that an even support is given to the screening cloth 110.

The dimensions, shape and distance between lamellas 111 may be chosen to assure the lamellas 111 do not overlap, when the screening body 11 is wound on the roller shaft 14 as will be described in further detail below.

In the specific embodiment shown in Figs 6 and 7, each side rail 21 , 22 is provided with a corner cap 24 comprising a cap element 240 and a stationary element 245. Flanges (not shown in detail) of the side rail 22 define a track 221 with a track opening configured to receive at least the bottom profile 15, by its opposing ends 150. As mentioned in the above, “ends” of the bottom profile 15 is to be construed to encompass any structure of the bottom profile 15 suitable to interact with the side rails 21 , 22. Here, the ends are provided as separate elements 150, but one-piece configurations are conceivable as well. In the embodiment shown, also a side edge of the screening body 11 is received and guided in the respective side rail. Also visible in Fig. 6 is a side cover 30 and a positioning device 40.

Referring to Figs 8a and 8b, the configuration of a lamella 111 is shown.

Each lamella 1111 of the set of lamellas comprises a top element 112 positioned on a first side 110a of the screening cloth 110 and a bottom element 113 positioned on a second, opposite side 110b of the screening cloth 110. The top element 112 and the bottom element 113 are held together by means of a mechanical connection, sandwiching the screening cloth 110 between them. By the term “mechanical connection” is encompassed connecting techniques not involving adhesion in the form of glue or chemical bonding of the material of the screening cloth 110 and the top and bottom elements 112, 113 of the lamella 111. Neither is penetration of the screening cloth 110 foreseen. The screening cloth 110 is thus substantially intact, if it is for some reason desirable to disassemble the screening arrangement 1 , in particular the screening body 11.

The top element 112 of each lamella 111 has an outwardly projecting outer shape relative to the first side 110a of the screening cloth 110, defining a first side portion 1121 , a second side portion 1122, and an apex 1123, the lamella length L111 being defined as the distance between the first and second side portions 1121 , 1122. Although alternative configurations are conceivable, it is preferable that the apex 1123 is as shown provided substantially halfway between the first side portion 1121 and the second side portion 1122.

The selection of the particular outwardly projecting shape is made in accordance with user wishes or other considerations, but is typically part- cylindrical, hyperbolic, elliptic and polygonal, or a combination of such shapes.

As shown, the top element 112 of each lamella 111 delimits a concave hollow 1124 facing the first side 110a of the screening cloth 110, said hollow 1124 defining an opening with a pre-defined opening length Lopen. The shape and size of the first side portion 1121 and the second side portion 1122, which extend substantially in-between the two side edges of the screening cloth 110 perpendicularly to the two side edges of the screening cloth 110, are chosen according to desire, but typically a curved, rounded or chamfered edge is provided.

Correspondingly, the bottom element 113 of each lamella 111 has a first side portion 1131 and a second side portion 1132 and defines an outwardly projecting outer shape relative to the second side 110b of the screening cloth 110 up to an apex 1133. Also this apex 1133 is preferably provided substantially halfway between the first side portion 1131 and the second side portion 1132, and is located in the concave hollow 1124 of the top element 112, at least partly sandwiching the screening cloth 110 in the assembled state of the lamella 111.

The first side portion 121 and the second side portion 122 of the top element 112 define a respective receiving space 1121a, 1122a for the first side portion 1131 and the second side portion 1132 of the bottom element 113. Further, the respective receiving space of the first side portion 121 and the second side portion 122 of the top element 112 define opposing locking flanges for the bottom element 113 and the screening cloth 110, such that the force of engagement between the top element 112 and the bottom element 113 is increased when tensioning the screening cloth 110 in the longitudinal direction of the screening body 11 .

Referring back to the above, it is preferred that the outwardly projecting outer shape of the bottom element 113 substantially matches the outwardly projecting outer shape of the top element 112, the top element 112 and the bottom element 113 each preferably having a part-cylindrical shape having substantially matching radii of curvature matching a radius R14 of the roller shaft 14.

Fig. 10 show a number of dimensions relevant to the definitions of the mutual relationship between the top element 112 and the bottom element 113. These dimensions include: Flext for the exterior height of the lamella 111 ; Hint for the interior height of the lamella 111 and T112 for the thickness of the top element 112 of the lamella 111. A radius of curvature RC111 of the lamella 111 is indicated as well.

In accordance herewith, the number of lamellas 111 and the distance A, B between adjacent lamellas 111 are in the embodiment shown chosen such the lamellas 111 do not overlap in the wound position of the screening body 11 on the roller shaft 14. Reference is here made to Figs 11 and 12. Further details shown in these figures are a first groove 141 and two second grooves 142 of the roller shaft 14. The first groove 141 is configured to receive a retention element 114 connected to the first end of the screening body 11 , and the second grooves 142 are configured to contribute to the driving of the roller shaft 14.

Preferably, the top element 112 and the bottom element 113 are made from aluminium. The top element 112 is for instance provided as an extruded profile, and the bottom element 113 is provided as a flexible plate, preferably with a profiling section 1133, more preferably including a spring leg 1135.

In the following, a preferred method for manufacturing a screening body 11 for a screening arrangement 1 , with a screening cloth 110 and set of lamellas 111 will be described in some detail, with particular reference to Figs 9a and 9b. The method comprises the steps of: providing a screening cloth 110 having a predefined width extending between two side edges, a predefined length between a first end portion and a second end portion, and a first side 110a and a second side 110b, the second side 110b being opposite to the first side 110a, providing a lamella by the steps of:

- providing a top element 112,

- providing a bottom element 113,

- placing the top element 112 in abutment with the first side 110a of the screening cloth 110 and the bottom element 113 an abutment with the second side 110b of the screening cloth 110,

- aligning the bottom element 13 with the top element 12,

- connecting the top element 112 and the bottom element 113 by means of a mechanical connection while sandwiching the screening cloth 110 between them, and repeating the lamella providing step for the required number of lamellas of said set.

In the embodiment of the lamella 111 shown and described in the above, the step of providing the lamella 111 includes providing the top element 112 with an outwardly projecting outer shape defining a first side portion 1121 , a second side portion 1122, and an apex 1123, a lamella length L111 being defined by the distance between the first and second side portions 1121 , 1122, and wherein the top element 112 is provided with a concave hollow 1124 defining an opening with a pre-defined opening length Lopen, the first side portion 121 and the second side portion 122 of the top element 112 defining opposing locking flanges with a respective receiving space 1121a, 1122a.

Here, the step of providing the lamella 111 includes providing the bottom element 113 as a flexible plate with a first side portion 1131 and a second side portion 1132, said flexible plate being provided in a bent shape with a peak 1133a and having a total length substantially corresponding to the path along the concave hollow 1124 between the receiving spaces 1121a, 1122a of the top element 112 and a projected length not exceeding the opening length Lopen of the hollow 1124 of the top element 112.

In order to gain full advantage of this, the step of providing the lamella 111 includes substantially matching the outwardly projecting outer shape of the bottom element 113 to the outwardly projecting outer shape of the top element 112, preferably as part-cylindrical shapes having substantially matching radii of curvature RC111 matching a radius R14 of a roller shaft 14 of the screening arrangement 1 .

The step of non-adhesive, non-penetrating connection of the top element 112 and the bottom element 113 by means of a mechanical connection while sandwiching the screening cloth 110 between them comprises: orientating the bent, flexible plate configured to form the bottom element 113 in front of the concave hollow 1124 of the top element 112 such that the peak 1133a is pointing away from the apex 1123 of the top element 112, inserting the first and second side portion 1131, 1132 of into the respective receiving space 1121a, 1122a of the first and second side portion 1121 , 1122 of the top element 112, and pressing the flexible plate configured to form the bottom element 113 into the hollow 1124 of the top element 112 while deforming the flexible plate into the shape of the bottom element 113, thereby sandwiching the screening cloth 110 in-between the top element 112 and the bottom element 113.

To this end, a pressing tool 50 with a pressing surface 51 configured to deform the flexible plate into the shape of the bottom element 113. may be provided.

Specific embodiments of the invention have now been described. However, several alternatives are possible, as would be apparent for someone skilled in the art. Such and other obvious modifications must be considered to be within the scope of the present invention, as it is defined by the appended claims.

List of reference numerals

I screening arrangement

2 roof window

3 frame structure 3a top frame member 3b side frame member 3c side frame member 3d bottom frame member

4 sash structure

4a top sash member 4b side sash member 4c side sash member 4d bottom sash member

5 hinge

6 fitting

7 pane

8 stay

10 return element

I I ’ prior art screening body (Fig. 2b)

11 screening body

110 screening cloth

110a first side of screening cloth 110b second side of screening cloth

111 lamella

112 top element of lamella

1121 first side portion of top element 1121a receiving space

1122 second side portion of top element 1122a receiving space

1123 apex

1124 hollow

113 bottom element of lamella

1131 first side portion of bottom element

1132 second side portion of bottom element 1133a peak / apex

1133b profiling section

1134 hollow

1135 folded leg

114 retention plate

12 guidance cord

13 tensioning device

14 roller shaft

141 first groove

142 second groove

15 bottom profile 150 end of bottom profile

21 first side rail

22 second side rail

221 track

23 top casing

231 solar panel

232 cover portion

233 end portion

234 top casing hinge

24 corner cap

240 cap element 245 stationary element

25 corner cap

30’ prior art side cover (Fig. 2b)

30 side cover

40 positioning device / clip

50 pressing tool

51 pressing surface of tool

W1 winding direction

W2 unwinding direction

Hext exterior height of lamella Hint interior height of lamella

L111 lamella length (in longitudinal direction of screening body 11)

Lopen opening length of hollow in lamella top element

R14 radius of roller shaft 14

RC1 11 radius of curvature of lamella 111

T112 thickness of top element of lamella