BACKGROUND

The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.

Aspects of the invention relate to a flexible sunscreen intended for use in a sunshade assembly of the type comprising:

a flexible sunscreen having a central part and two opposed inwardly folded longitudinal edge flaps connected to the central part by means of folding lines;

two opposed longitudinal guides for receiving therein and guiding corresponding ones of the inwardly folded longitudinal edge flaps of the flexible sunscreen, which guides are provided with locking members for engaging an outer end of the inwardly folded longitudinal edge flaps for preventing these edge flaps from moving out of the longitudinal guides.

In some state of the art sunshade assemblies of such a type the cooperation between the guide locking members (for example a ridge extending from a guide leg into a guide channel) and the outer end of the inwardly folded longitudinal edge flaps not always may prevent that a longitudinal edge flap comes out of the guide (that means that such a guide cannot withstand a sufficient high level of lateral pull out force acting on the flexible sunscreen). This problem, among others, may be caused by the size of an entrance opening of the guide channel. One solution would be to reduce such size, but in some embodiments this is not possible because also other larger dimensioned members (other than the sunscreen's longitudinal edge flaps) are guided in the guide channel. Further, reducing the size of the entrance opening (or of other parts of the guide) can cause problems with tools used to manufacture such a guide (for example an extrusion tool, when used, then would be prone to premature collapse), whereas further due to wear of manufacturing tools it is very difficult (or nearly impossible) to maintain the dimensions of the guide, thus leading to an end product (guide) with properties which vary in an unpredictable manner.

It is an object of the present invention to provide an improved flexible sunscreen of the above type.

SUMMARY

This Summary and the Abstract herein are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary and the Abstract are not intended to identify key features or essential features of the claimed subject matter, nor are they intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.

The flexible sunscreen is characterized in that the central part of the flexible sunscreen mainly is manufactured from a first material with a first stiffness and wherein of the inwardly folded longitudinal edge flaps and of the parts of the central part adjacent the edge flaps at least part is made of a second material with a second higher stiffness.

Thus it is possible to offer said part of the longitudinal edge flaps and/or of the parts of the central part adjacent the edge flaps such a stiffness that the flexible sunscreen with said edge flaps is better retained in the longitudinal guides, while keeping the flexible sunscreen sufficiently flexible (for example for allowing it to be wound on a winding shaft). The stiffness of said edge flaps may vary in different directions. Generally the stiffness in transverse direction should be sufficiently high for preventing that the longitudinal edge flaps are pulled out of the longitudinal guides; in a longitudinal direction, however, the stiffness should be sufficiently low to allow an easy winding of the sunscreen on the winding shaft. Such different degrees of stiffness in different directions may be obtained by a material which is not uniform in all directions (for example a material comprising fibres oriented in specific directions).

In one embodiment of the flexible sunscreen the coefficient of friction of the second material is lower than the coefficient of friction of the first material. This results in a reduction of handling/driving forces required for moving the flexible sunscreen longitudinally along the longitudinal guides.

It is noted that the use of two different materials for the central part and for the longitudinal edge flaps also allows other properties of said materials to be different, if required.

It is conceivable that the second material is a plastic material, but also other materials (such as natural materials) may be used.

In a specific embodiment of the flexible sunscreen, the second material is impregnated in at least part of the surfaces of the inwardly folded longitudinal edge flaps. As a result the dimensions (specifically the thickness) of the longitudinal edge flaps substantially will remain the same, which may be advantageous when the dimensions of the longitudinal edge flaps and the longitudinal guides have been matched during design.

In such a case it is conceivable that the second material too is impregnated in the surfaces of parts of the central part of the flexible sunscreen adjacent the edge flaps and wherein the flexible sunscreen at the folding line has a restricted thickness. Generally, too impregnating parts of the central part will lead to a design in which the flexible sunscreen at the folding lines is (at least partially) impregnated and this could detrimentally influence the folding capacity. By applying a (restriction with) restricted thickness this may be compensated.

In another type of embodiments of the flexible sunscreen the second material is embodied as a separate layer of said second material at least partly surrounding and at least partly attached to the edge flaps. In this case the outer dimensions (such as thickness) of the inwardly folded longitudinal edge flaps generally will increase. The manner in which such a separate layer is attached may differ; as an non-limiting example it is conceivable to use an adhesive or to use welding techniques.

For example it is possible that the inwardly folded longitudinal edge flaps each, in the folded position, define an inner surface and an outer surface and wherein said separate layer at the inner surface extends substantially up to the folding line and wherein said separate layer at the outer surface ends at a distance from said folding line, wherein said distance ranges from 5-50% of the width of the inwardly folded longitudinal edge flaps measured between a folding line and respective outer end. The said distance over which the separate layer is missing seems beneficial in the overall performance of the longitudinal edge flaps and results in a promising increase of the pull-out force of the longitudinal edge flaps. The precise percentage may depend on different factors, among which dimensions and materials used.

As an alternative the inwardly folded longitudinal edge flaps each, in the folded position, again may define an inner surface and an outer surface and wherein said separate layer at the inner surface extends substantially up to the folding line and wherein said separate layer at the outer surface ends at a distance beyond said folding line and extends over at least part of the central part of the flexible sunscreen. In such a case the separate layer at the lower surface will continue over and past the folding line. As a result the parts of the central part next to the folding lines may be strengthened.

In such a case it is conceivable that the part of the separate layer extending beyond the folding line is not attached to said central part of the flexible sunscreen, such that the folding capacity remains sufficiently.

In an embodiment of the flexible sunscreen the inwardly folded longitudinal edge flaps are completely made of said second material which partly encloses and/or extends through the central part of the sunscreen and which at the location of the folding line has a restricted thickness. The central part, for example, may comprise through-holes through which the second material extends from one surface to the opposite surface.

Whereas in the most common configuration the inwardly folded longitudinal edge flaps are folded such that they (in a normal operational position of the flexible sunscreen) extend above the central part, in a special embodiment the inwardly folded longitudinal edge flaps extend below the central part of the sunscreen. This may promote the manner in which said longitudinal edge flaps are retained in the longitudinal guides.

In a second aspect the invention relates to a sunshade assembly comprising a flexible sunscreen having two opposed inwardly folded longitudinal edge flaps, a leading edge and a trailing edge, a winding shaft for winding and unwinding the flexible sunscreen at its trailing edge, an operating beam attached to the leading edge and two opposed longitudinal guides for receiving therein and guiding corresponding ones of the inwardly folded longitudinal edge flaps of the flexible sunscreen, which guides are provided with locking members for engaging an outer end of the inwardly folded longitudinal edge flaps for preventing these edge flaps from moving out of the longitudinal guides, wherein the flexible sunscreen is embodied in accordance with the present invention.

