Title: Insect screen

The invention relates to an insect screen for screening a

constructional opening, the insect screen being provided with a sheet of gauze material having two opposite longitudinal edges and at least two retaining sections for retaining the two opposite longitudinal edges to the constructional opening.

Such insects screens are known as fixed type where the gauze material is connected to a circumferential frame. Also known are insect screens of a roll-up type where the gauze material is movably included and by opposite longitudinal edges thereof is guided in side guides. The gauze material can then be rolled up in a top housing. Also, the roll-up insect screens are normally provided with a bottom rail. With insect screens of the roll- up type, the side guides and the top housing are often permanently attached to a window frame. Insect screens of the fixed type are often removably attached in a window frame so that they can be stored during winter months.

A recurring problem with insect screens are the connections of the screen gauze material to other components of the insect screen, such as circumferential frames, roll -up devices, bottom rails and/or side guides.

With fixed insect screens, the screen gauze is mostly clamped in a circumferential groove in the circumferential frame, by pressing the gauze material with a spline laid on it into the circumferential groove. Such constructions are described in patent publications US 3321885 and

US 4005737. The most commonly used screen gauze material is a PVC-layer (polyvinyl chloride) -coated woven from glass fibre. This material is supplied by, inter alia, the firm of Phifer Wire Products, Inc, from Tuscaloosa, Alabama, USA. This material allows only limited bending or folding, because otherwise the encased glass fibres break. As a result of pressing the screen gauze with a spline into a mounting groove, such fibre breakages often occur, but they are generally tolerated because in practice they have little effect on the utility of the connection. Another drawback, however, is that as the spline is rolled in, the position and the tension of the screen gauze changes, so that the gauze attachment becomes uneven.

With roll-up insect screens, it has been proposed to use melting and welding connections for attachment of the screen gauze to the roll or the bottom rail, as described in patent publications WO 01/36778 and US 6463990. It has also been proposed to attach retaining means for a connection with the side guides to the screen gauze by welding or melting. Such proposals are described in patent publications US 3149665 and EP 0790384. Such

connections are hindered by the poor weldability of the PVC encased glass woven screen gauze. The known welding and melting connections therefore all utilize a different material that fuses with the PVC casing or incorporates this in the mass through enclosure.

Other materials, which are better weldable and can fuse with themselves, such as polypropylene, have failed to find application as screen gauze due to their poor resistance to UV radiation.

The object of the invention is to provide a solution to these problems. Accordingly, it is also an object of the present invention to eliminate or ameliorate at least one of the disadvantages of the state of the art. It is another object of the present invention to provide alternative solutions that can be carried out more simply and that, furthermore, can be manufactured comparatively economically. Alternatively, it is an object of the invention to provide to the public an at least useful option.

To that end, the invention provides an insect screen and a method for forming a welded connection as defined in one or more of the appended claims and subclaims.

Presently, the invention will be further elucidated on the basis of a number of exemplary embodiments as shown in the accompanying drawings. In the drawing: Fig. 1 shows an insect screen according to the invention of the fixed type;

Fig. 2 shows an insect screen according to the invention of the roll-up type;

Fig. 3 is a partial cross section of the fixed insect screen from Fig. 1;

Fig. 4 is a cross section of an alternative wooden frame element for use in the invention; still without screen gauze;

Fig. 5 shows a manufacturing step for the insect screen from Figs. 1,

3 or 4;

Fig. 6 is a partial cross section of the roll-up insect screen from

Fig. 2; and

Fig. 7 shows a manufacturing step of the insect screen from Figs. 2 and 6.

In Fig. 1, a corner part is shown of a normally rectangularly framed insect screen 1. The insect screen 1 is assembled in the usual manner from hollow edge sections 3A, 3B which are mitred to form a corner 5 and to which a sheet of screen gauze, mesh material or screen material 7 is attached. By the edge sections, such as 3A and 3B, in the usual manner, a circumferential frame or framing is formed. As is usual for fixed types of insect screens, the framing is to be placed in or in front of a window opening. The mitred edge sections 3A, 3B can be internally provided with a corner connector (not shown, but conventional). Further, it can be seen in Fig. 1 that the edge sections 3A, 3B are each provided with an undercut groove 9A, 9B, respectively. Received in these undercut grooves 9A, 9B is a spline or inlay 11 from polypropylene material. Preferably, the polypropylene material for the spline 11 is one of the type in which a liquid crystalline polymer (LC-polymer) is incorporated that renders the polypropylene material UV-resistant. The sheet of screen gauze 7 is likewise woven from polypropylene fibres of the type whose UV-resistance has also been enhanced through addition of an LC-polymer. The embodiment 10 050775

according to Fig. 1 will be further set out hereinbelow in a discussion of Figs. 3 to 5.

In Fig. 2, a second embodiment of an insect screen 51 according to the invention is shown. The insect screen 51 is of the roll-up type with a roll in a top housing 53 and side guides in the form of side guide sections or side guide channels 55, of which only one is represented in Fig. 2. A roll-up sheet of screen gauze, or gauze material 57, respectively, is received by its longitudinal edges in the side guide section 55. The top end of the sheet of gauze material 57 is attached in the top housing 53 to a roll (not visible, but conventional) and has a lower edge attached to a bottom rail 59. As is customary with roll-up insect screens, the bottom rail 59 is guided in the side guides 55 and can be latched thereto in the closed position. Here too, the gauze material 57 is of polypropylene yarns which have been made UV-resistant through addition of a liquid crystalline polymer (LC-polymer). The embodiment according to Fig. 2 will be further described hereinbelow with reference to Figs. 6 and 7.

Fig. 3 is a cross section in partial view of an edge section 3A with a screen gauze 7 attached thereto. The screen gauze 7 is attached to the spline 11 through fusion, in the form of a welded connection 12. The

polypropylene material of the yarns of the screen gauze material 7 and the spline 11 are predominantly properly weldable without the visible side of the screen gauze 7 being damaged. Moreover, through the addition of an

LC-polymer the polypropylene material has become suitable for use in insect screens, which, as is known, are exposed to UV-radiation. In the exemplary embodiment shown the spline 11 has in cross section outwardly elastic arms 11 A, 11B which realize a snap connection with the undercut groove 9 A.

As an alternative to the edge section of Fig. 3, Fig. 4 shows an edge section 13 from wood. The wooden edge section 13 is also provided with an undercut, for the most part circular, groove 19, which may be of circular design. In the circularly undercut groove 19, a spline or inlay 21 may be snapped in or rolled in, which is formed from a polypropylene material with an addition of an LC-polymer for obtaining the desired UV-resistance. To this spline 21, again, a screen gauze material from UV-resistant polypropylene yarns can be welded. This screen gauze material is not shown in Fig. 4 but is basically identical to the gauze material 7 shown in Figs. 1 and 3. After fusion with the gauze material, the spline 21 can take a flattened shape so that the part that projects above the groove 19 is no longer round.

Fig. 5 shows a manufacturing step for obtaining the insect screens of the fixed type, to which Figs. 1, 3 and 4 relate. The framing built up from edge sections, here indicated with reference numeral 3, is first provided with the inlay or spline 11. The screen material 7 then is not attached yet and is laid as a sufficiently large sheet on top of the framing 3 with the inlay 11 laid therein. Optionally, the screen gauze 7 can then be held stretched under tension. Then an anvil 31 of a heat press is brought into contact with the top of the screen gauze 7. The heat press installation can utilize heat, high frequency or other suitable welding techniques to fuse the screen gauze 7 with the sphne inlay 11.

In Fig. 6, a cross section in partial view is shown of a side guide 55 from Fig. 2 having received therein a longitudinal edge 61 of the screen gauze 57. The longitudinal edge 61 is formed by folding the screen gauze material 57 in part back onto itself and connecting it through welding or melting and having a more inwardly situated edge thereof form an upwardly springing hook edge 63. During rolling up, this upwardly springing hook edge 63 is pressed against the polypropylene gauze material 57 but upon unrolling springs clear of the underlying gauze material 57. In the side guide channel 55, this hook edge 63 is caught behind a diagonally inwardly directed resilient strip 65. The resilient strip 65 is received in a dovetail groove 67 of the side guide section 55. This hook edge 63 forms the retaining means for retaining each of the at least two opposite longitudinal edges 61 to an associated one of the side guide sections 55 present at least in duplicate. As the hook edge 63 and the resilient strip 65 extend virtually throughout the height and length, respectively, of the side guide 55, the screen gauze 75 cannot dislodge from the side guide by wind or bumping. In the event of an unduly high load the screen gauze can still slip out of the side guide, but it can thereupon be re-placed again by the end user without damage. It is again the advantageous welding possibility of the polypropylene (PP) gauze that makes this solution possible.

In Fig. 7, a method step is shown by which the longitudinal edge 61 can be obtained. What is achieved by utilizing an anvil 71 of a heat press that is placed directly on the turnover fold 69 is, in addition to fusion of the polypropylene material, that the turnover fold obtains a permanent form. In this way, a reinforced band is obtained with which the rolling screen remains well rollable and the increase in roll-up diameter remains limited. The strengthened outer edge with the upstanding hook edge 63 provides a proper restraint from slipping out of the side guide.

With this rolling screen variant too, advantageously, a screen gauze from UV-stable polypropylene yarns is used. These UV-resistant PP-yarns are obtained by adding to the PP material an LC-polymer of a suitable type.

A suitable type of LC-polymer concerns a polymer whose form changes under the influence of heat and pressure. The polymer forms a surface film that is sunlight resistant and protects the underlying material. Such PP-materials are known from the article: "Osaka researchers develop light-resistant

polypropylene", which appeared in the specialist journal "New Materials Asia" of June 2007. Further, European patent EP 0064802 to ICI offers a number of possibilities of adding LC-polymers to polypropylene.

Although the invention has been described above on the basis of examples implemented as insect screens, it will be clear to the skilled person that the invention can also be used with sun screens or black out means, such as roller blinds, and for use both in the interior and on the outside of buildings.

It is believed that the construction and the operation of the present invention are clearly apparent from the above description. The invention is not limited to any embodiment described herein and, within the reach of the skilled person, modifications are possible that are to be understood to fall within the scope of protection. Also, all kinematic inversions are understood to be included within the scope of protection of the present invention. Terms such as "consisting of, when used in this description or the accompanying claims, should not be construed as an exhaustive enumeration, but more as having an inclusive meaning. Terms such as: "means to ..." should be read as:

"component formed for..." or "element constructed for"... and are to be understood to include all equivalents for the described constructions. The use of terms such as: "critical", "advantageous", "desired", etc., is not intended to limit the invention. Furthermore, also properties that are not specifically or expressly described or required in the construction according to the present invention are included without departing from the scope of protection.