Abstract:
A screen element is provided for motor vehicles, in which a piece of flat material extends in a surface area. The piece of flat material has strands which are inherently stiff to enable the flat material to stand alone without a frame. The strands also provide primary stability for the screen element. A frame is provided on at least one edge area of the piece of flat material. The frame providies secondary stability for the screen element.

Description:
[0001]    This application is a continuation-in-part of co-pending U.S. patent application Ser. Nos. 09/804,488 filed Mar. 12, 2001 and 10/004,273 filed Oct. 23, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to a screen element for motor vehicles, in particular, a wind blocker or a sun screen, comprising a piece of flat material extending in a surface area.  
           [0003]    In screen elements known to date for motor vehicles, a flexible material clamped in a frame has been used for the piece of flat material in order, for example, to prevent a wind blocker from fluttering.  
           [0004]    However, such a flexible flat material has the disadvantage that it has to be firmly attached to a frame and also has to be clamped therein.  
           [0005]    The object underlying the invention is, therefore, to so improve a screen element of the generic kind that it can be manufactured more economically.  
         SUMMARY OF THE INVENTION  
         [0006]    This object is accomplished in accordance with the invention with a screen element of the kind described at the outset by the piece of flat material comprising a woven, knitted or braided fabric consisting of inherently stiff wires or fibers and thus being of inherently rigid construction.  
           [0007]    The advantage of the solution according to the invention is to be seen in that such a piece of flat material already exhibits such a sufficient inherent rigidity that the stability does not have to be primarily ensured by the frame.  
           [0008]    Furthermore, such a piece of flat material has the advantage that the tensioned mounting of the piece of flat material on the frame, which involves high expenditure, can be dispensed with.  
           [0009]    Such a piece of flat material for a wind blocker or a sun screen for motor vehicles is preferably produced from a woven, knitted or braided fabric consisting of wires which are so thin that it allows one to see through it, so that, for example, in the case of a wind blocker one can still look through the screen element with the rearview mirror.  
           [0010]    Regarding the structure of the wires or fibers, it is, for example, conceivable to use carbon fibers, which are likewise inherently stiff.  
           [0011]    Such carbon fibers do, however, have the disadvantage that they do not allow subsequent shaping. For this reason, it is particularly advantageous for the wires or fibers to be produced from a shapeable material, but which is nevertheless inherently stiff, so that it is possible not only to spread out the flat material in a plane but also to give the flat material, for example, a curved shape.  
           [0012]    It is, for example, conceivable to also use plastic wires or fibers which, for example, are thermoplastically shapeable.  
           [0013]    However, a particularly expedient solution makes provision for the wires to be made of metal, for these, on the one hand, to be shapeable in a simple way by known methods, but, on the other hand, to also exhibit a sufficiently high degree of inherent stiffness.  
           [0014]    Since, with the solution according to the invention, the piece of flat material itself has a sufficiently high degree of inherent rigidity, it is, in principle, not necessary to provide a separate frame.  
           [0015]    However, to achieve an improved edge rigidity and hence an improved handling of the screen element, provision is preferably made for the wires or fibers in an edge area of the piece of flat material to extend at least partially transversely to the surface area in which the piece of flat material extends.  
           [0016]    This results in a particularly simple way in an additional edge stiffening so that the total stability of the screen element does not have to result from the inherent stability of the piece of flat material itself, but rather the edge area extending at least partially transversely to the surface area forms a stabilizing frame around the piece of flat material.  
           [0017]    An embodiment of such a screen element makes provision for the wires in the edge area to be shaped so as to form a surrounding edge loop.  
           [0018]    A further advantageous embodiment makes provision for the wires in the edge area to be shaped so as to form a bead.  
           [0019]    In conjunction with the embodiments explained so far it is assumed that the additionally stabilizing frame is formed from the edge area of the piece of flat material itself.  
           [0020]    However, a further advantageous embodiment makes provision for the piece of flat material to have an edge area which has a frame connected thereto.  
           [0021]    Such an additional frame has the advantage that it is possible to create in the edge area a closure around the screen element, which is advantageous with respect to appearance and technical safety so that, in particular, there is no necessity for complicated machining of the edge area in order to achieve a closure which is acceptable with respect to appearance and technical safety.  
           [0022]    Furthermore, an additional frame has the advantage that it also offers the possibility, in the simple, conventional way, of implementing the holder of the screen element on the motor vehicle with conventional holding elements engaging at the edge.  
           [0023]    However, the great advantages of the inherently rigid piece of flat material are nevertheless still present in this embodiment. These are, on the one hand, that the necessity of tensioning the piece of flat material is dispensed with, and, on the other hand, that in addition to its inherent rigidity, the piece of flat material is also adaptable to any surface shapes which differ from a level surface.  
           [0024]    Such a frame can be implemented in many different ways. One advantageous embodiment makes provision for the frame to comprise at least one frame part positioned on the edge area.  
           [0025]    Such a frame part can be fixed on the edge area in many different ways. It is, for example, conceivable to simply hold the edge area in a positively locking manner on the frame part, for example, by means of a recess provided in the frame part. In the simplest case, the recess can be implemented by two frame parts connectable to each other, with the edge area being inserted into the recess when the frame parts are fitted together.  
           [0026]    The frame parts are preferably attached to each other, for example, by an adhesive or welding connection.  
           [0027]    A particularly advantageous solution makes provision for the edge area to be embedded in a frame part at least in connecting areas. Such embedding can be achieved by, for example, the frame part being softened in individual frame part elements so as to embed the edge area of the piece of flat material.  
           [0028]    Such softening of the frame part can be advantageously carried out in that, in order to create the connecting areas, the frame part made of thermoplastic material is acted upon by ultrasound to heat up and soften the thermoplastic material, so as to thus achieve an embedding of the edge area in the individual connecting areas.  
           [0029]    Another advantageous embodiment of the screen element according to the invention makes provision for the frame to be injection molded onto the edge area, i.e., the edge area is placed in an injection mold and injection molding is performed around the edge area.  
           [0030]    As an alternative to this, provision is made for the frame to be foamed onto the edge area.  
           [0031]    In another embodiment of the invention the screen element for motor vehicles comprises a stabilizing structure extending in a surface area, and comprising a web structure having openings between webs thereof and providing stability to the screen element, and a piece of flat material, maintained by the stabilizing structure in a position in which it extends over the said surface area within an outer contour of the stabilizing structure.  
           [0032]    The advantage of this embodiment is to be seen in the fact that the stabilizing structure itself can provide sufficient stability to the screen element in order to maintain the piece of flat material extending over the said surface area. In particular, such a stabilizing structure makes it unnecessary to provide a stable frame which itself has to provide the stability for the screen element and is therefore expensive. In accordance with the present invention the stabilizing structure with the web structure can be manufactured much more cost effectively.  
           [0033]    No specific details have been given regarding the shape of the outer contour of the stabilizing structure outlined above.  
           [0034]    In particular, it is of advantage for the stabilizing structure to comprise an outer rim element connected to the web structure.  
           [0035]    A further advantageous embodiment provides that the stabilizing structure comprises an outer frame connected to the web structure.  
           [0036]    In particular, the outer frame can be formed by the rim element of the stabilizing structure and a further frame element, for example, a cover element for the rim.  
           [0037]    The stabilizing structure can be designed in a variety of ways. One embodiment provides that the stabilizing structure comprises webs interconnected with one another.  
           [0038]    In particular, the webs are interconnected at points of intersection thereof.  
           [0039]    The webs may be designed in any way which allows formation of a web structure.  
           [0040]    According to one advantageous embodiment the stabilizing structure comprises crossovers forming the webs of the web structure. Such crossovers can be formed like bars or rods or legs or arms.  
           [0041]    In a specific embodiment it is provided that at least some of the webs extend parallel to each other. Such an embodiment has the advantage that the plurality of webs can be used to increase the stability of the stabilizing structure.  
           [0042]    An advantageous variant of a screen element provides a first number of webs extending parallel to one direction and a second number of webs extending parallel to a second direction, with the second direction extending transversely to the first direction. Such a web structure results in a grid-like structure which provides the stabilizing structure with a high degree of stability.  
           [0043]    In particular, it is of advantage for the first and second directions to extend transversely to supports forming the rim.  
           [0044]    In one embodiment it is provided that the web structure is formed as an integral part. This means that the webs of the web structure are interconnected with each other in order to form the integral part.  
           [0045]    A further advantageous embodiment provides that the stabilizing structure is formed as an integral part. This means that the web structure as well as the rim element are formed as an integral part.  
           [0046]    No specific details have been given regarding fixation of the piece of flat material with respect to the stabilizing structure. One embodiment provides that the piece of flat material is fixed to the rim element of the stabilizing structure.  
           [0047]    Such fixation of the flat material is possible in different ways. For example, it is possible to fix the flat material on the rim element by gluing or welding or clamping.  
           [0048]    In one specific embodiment the rim element is provided with a receiving means for an outer edge portion of the piece of flat material.  
           [0049]    In particular, it is of advantage to maintain the outer edge portion of the piece of flat material in the receiving means by an insert.  
           [0050]    Such an insert can be any kind of element specifically adapted to be inserted into the receiving means. One embodiment provides that the insert is part of a cover element covering the rim element.  
           [0051]    No details have been given regarding the relative arrangement of the web structure and the piece of flat material. One embodiment provides that the web structure extends on at least one side of the piece of flat material.  
           [0052]    A specific embodiment is designed such that the flat material extends in a first surface and the web structure extends in a second surface which is different from the first surface.  
           [0053]    In particular, the first surface and the second surface extend essentially parallel to each other.  
           [0054]    In general, there can be provided one web structure and one piece of flat material at one side thereof.  
           [0055]    An alternative embodiment could also provide two pieces of flat material on opposite sides of one web structure or a further embodiment could provide two web structures and the piece of flat material arranged therebetween.  
           [0056]    No details have been given regarding the relative position of the web structure and the piece of flat material.  
           [0057]    One embodiment provides that the piece of flat material abuts on one side of the web structure.  
           [0058]    Another advantageous embodiment provides arrangement of the piece of flat material with a spacing between the piece of flat material and the web structure. Such a spacing between the piece of flat material and the web structure has the advantage that the optical appearance of the piece of flat material, which usually is a very thin material, is not affected by the web structure. Such a solution offers the advantage that the quality of the surfaces of the web structure directed towards the piece of flat material has no influence on the optical appearance of the piece of flat material and therefore there is a higher degree of freedom with respect to precision and design of the web structure.  
           [0059]    No specific details of the piece of flat material have been given. For example, the piece of flat material could be made of stiff material, in particular, material which comprises strands or fibers which are stiff.  
           [0060]    However, with use of a stabilizing structure enough stability is provided to keep the piece of flat material extended. In such a case, an advantageous embodiment provides that the piece of flat material is made of a material with bending slackness.  
           [0061]    Such a piece of flat material can be made of a wind-tight material.  
           [0062]    Such a wind-tight material can be made of an air impermeable foil.  
           [0063]    However, since wind stop devices always use an air permeable material for a wind blocker one advantageous embodiment provides that the piece of flat material is made of an air permeable material provided with openings.  
           [0064]    These openings are much smaller than the openings of the web structure. In particular the openings in the web structure are of such size that the web structure is not even wind-tight.  
           [0065]    For example, the openings in the web structure are larger by more than a factor of 100 or even a factor of 1000 than the openings in the piece of flat material.  
           [0066]    There are various possibilities for design of the the piece of flat material. One possibility provides that the flat material comprises at least one of a woven, knitted or braided fabric.  
           [0067]    Another possibility provides that the piece of flat material comprises a foil provided with openings.  
           [0068]    In order to provide the piece of flat material with an advantageous appearance the piece of flat material is made of elastic material which can be tensioned in at least one direction.  
           [0069]    Another possibility would be to make the piece of flat material from an inelastic material.  
           [0070]    Further features and advantages of the solution according to the invention are the subject matter of the following description and the drawings of several embodiments.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0071]    [0071]FIG. 1 shows a sectional illustration of a body of a convertible vehicle with a first embodiment of a wind stop device mounted thereon in a functional position;  
         [0072]    [0072]FIG. 2 shows an illustration of the first embodiment of the wind stop device considered in the direction of arrow A in FIG. 1;  
         [0073]    [0073]FIG. 3 shows an illustration of the first embodiment of the wind stop device during folding about a connection folding axis;  
         [0074]    [0074]FIG. 4 shows a schematic illustration of further steps for the folding together of the wind stop device;  
         [0075]    [0075]FIG. 5 shows a perspective illustration of the first embodiment of the wind stop device in a folded position;  
         [0076]    [0076]FIG. 6 shows a partially folded out illustration of the first embodiment of the wind stop device with illustration of one embodiment of a releasable connection for one of the wind blocker parts and one of the cover parts;  
         [0077]    [0077]FIG. 7 shows an illustration similar to FIG. 2 of a second embodiment of an wind stop device;  
         [0078]    [0078]FIG. 8 shows an illustration similar to FIG. 3 of the second embodiment of the wind stop device;  
         [0079]    [0079]FIG. 9 shows an illustration similar to FIG. 4 of the second embodiment of the wind stop device and  
         [0080]    [0080]FIG. 10 shows an illustration similar to FIG. 5 of the second embodiment of the wind stop device.  
         [0081]    [0081]FIG. 11 a perspective illustration of a first embodiment of a screen element according to the present invention;  
         [0082]    [0082]FIG. 12 a partially enlarged illustration of the piece of flat material;  
         [0083]    [0083]FIG. 13 a perspective section along line  13 - 13  in FIG. 11;  
         [0084]    [0084]FIG. 14 a section similar to FIG. 13 through a second embodiment;  
         [0085]    [0085]FIG. 15 a section similar to FIG. 13 through a third embodiment;  
         [0086]    [0086]FIG. 16 a section similar to FIG. 13 through a fourth embodiment;  
         [0087]    [0087]FIG. 17 a section similar to FIG. 13 through a fifth embodiment;  
         [0088]    [0088]FIG. 18 a perspective illustration of a sixth embodiment of a screen element according to the invention;  
         [0089]    [0089]FIG. 19 a perspective representation of a stabilizing structure of said sixth embodiment;  
         [0090]    [0090]FIG. 20 a representation of unassembled elements of said sixth embodiment of the screen element and  
         [0091]    [0091]FIG. 21 a sectional view along lines  21 - 21  of an assembled screen element according to the sixth embodiment.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0092]    A wind stop device for a motor vehicle, the body  10  of which is illustrated in sections in FIGS. 1 and 2, comprises a wind blocker  12  which projects upwards beyond a belt line  14  of the body  10  of the convertible vehicle as well as a cover  16  which covers a section  18  located behind the wind blocker  12  of a passenger compartment opening located at the level of the belt line  14 , for example, this is a section  18  located above rear seats  20 , wherein the wind blocker  12  is essentially arranged directly behind headrests of front seats of the body  10  which are not illustrated.  
         [0093]    The cover  16  is preferably articulatedly connected to the wind blocker  12  and both can be connected to the body  10  in the area of the belt line  14  via fixing devices  22 ,  24 , wherein the fixing devices  22 ,  24  are arranged either on the wind blocker  12  or on the cover  16 , as will be explained in greater detail in the following.  
         [0094]    The wind blocker  12  is formed by a wind blocker frame  30  which has a lower frame support  32  and an upper frame support  34  and outer connecting supports  36 ,  38  connecting the lower frame support  32  and the upper frame support  34  to one another, these connecting supports each connecting outer end areas of the lower frame support  32  and the upper frame support  34  to one another so that the frame  30  encloses a frame opening  40 .  
         [0095]    A flat material  42  extends in the frame opening  40 , is held on the wind blocker frame  30  and is preferably held by the wind blocker frame  30 .  
         [0096]    In order to form two wind blocker parts  50  and  52  of the wind blocker  30  which can be pivoted relative to one another about a wind blocker folding axis  44 , the lower frame support  32  and the upper frame support  34  are provided approximately centrally with a respective hinge  54  and  56 , the hinge axes of which are arranged coaxially to the wind blocker folding axis  44 .  
         [0097]    As a result, the lower frame support  32  and the upper frame support  34  each comprise two frame support parts  32   a, b  or  34   a, b  separated by the hinges  54  and  56 . The frame support parts  32   a ,  34   a  form with the connecting support  36  a C-shaped wind blocker frame part  58   a  while the frame support parts  32   b  and  34   b  with the connecting support  38  form a C-shaped wind blocker frame part  58   b  and both wind blocker frame parts  58   a, b  border on the wind blocker folding axis  44  with their open sides.  
         [0098]    Furthermore, the cover  16  comprises two cover parts  60  and  62  which can be folded relative to one another about a common cover folding axis  64 .  
         [0099]    The cover  16  also preferably comprises a cover frame  70  which, in this embodiment, comprises a front frame support  72  and a rear frame support  74 , the two being connected to one another by outer connecting supports  76  and  78 . Furthermore, inner connecting supports  80   a  and  80   b  are provided which extend on both sides of the cover folding axis  64  and likewise connect the front frame support  72  and the rear frame support  74  to one another, wherein the front frame support  72  and the rear frame support  74  are separated along the cover folding axis  64  and likewise preferably connected to one another by means of hinges  82  and  84  which are arranged with their hinge axes coaxially to the cover folding axis  64 .  
         [0100]    It is, however, also possible to arrange the hinges  82  and  84  in the area of the inner connecting supports  80   a  and  80   b  and thus configure the connecting supports  80   a  and  80   b  so as to be foldable relative to one another about the cover folding axis  64 .  
         [0101]    As a result, the inner connecting support  80   a  and the outer connecting support  76  form a frame section  85   a  together with a front frame support part  72   a  extending between them and the rear frame support part  74   a  extending between them and the inner connecting support  80   b  forms a further frame section  85   b  with the outer connecting support  78  and a front frame support part  72   b  extending between them and a rear frame support part  74   b , wherein each frame section  85   a  and  85   b  surrounds a frame opening  86   a ,  86   b , over which a flat material  88   a  and  88   b , respectively, extends, wherein the flat material is preferably held by the frame sections  85   a  and  85   b , respectively.  
         [0102]    In the functional position of the wind stop device, the wind blocker parts  50  and  52  are in an extended position and have a maximum extension in a direction of extension  91  parallel to the connection folding axis  90 . Furthermore, the cover parts  60  and  62  are also in an extended position and likewise have a maximum extension in the direction of extension  91 .  
         [0103]    Furthermore, the wind blocker  12  is connected to the front frame support  72  of the cover  16  with its lower frame support  32 , wherein this connection is preferably a connection which can be pivoted about a connection folding axis  90  extending transversely to a longitudinal direction of the vehicle and which, as will be explained in detail in the following, can be realized in the most varied of ways.  
         [0104]    In the functional position of the wind stop device illustrated in FIGS. 1 and 2, the two wind blocker parts  50  and  52  located in the extended position are aligned relative to one another in such a manner that they are approximately located in a plane E V  which extends approximately vertically, wherein the term approximately vertically comprises an angular deviation of plus/minus 30° in relation to the exactly vertical direction.  
         [0105]    The plane E V  is located transversely to a plane E H , in which the cover parts  60  and  62  are located in the functional position of the wind stop device, wherein the plane E H  extends approximately parallel to the belt line  14  of the body  10  in the section  18 .  
         [0106]    In order to fold the inventive wind stop device together, the wind blocker  12  and the cover  16  may be folded towards one another about the connection folding axis  90  such that a rear side  92  of the wind blocker  12  is located on an upper side  94  of the cover  16 , wherein for this purpose no folding about either the wind blocker folding axis  44  or the cover folding axis  64  need have taken place (FIG. 3).  
         [0107]    Moreover, as illustrated in FIG. 4, it is possible to fold one of the wind blocker parts  50  or  52 , for example, the wind blocker part  52  about the wind blocker folding axis  44  such that a front side  96  of the wind blocker part  52  is located on a front side  98  of the wind blocker part  50 , as illustrated in FIG. 5.  
         [0108]    In order to configure this folding as simply as possible, the flat material  42  is located each time in a surface area, preferably a plane E F , which essentially coincides approximately with the respective front side  96 ,  98  of the wind blocker parts  50 ,  52  and the wind blocker folding axis  44  is also preferably located in a line of intersection of these surface areas E F .  
         [0109]    Furthermore, it is possible to also fold the cover parts  60  and  62  about the cover folding axis  64 , for example, such that a lower side  100  of the cover part  62  is located on a lower side  102  of the cover part  60 .  
         [0110]    In order to configure the folding of the cover parts  60  and  62  as simply as possible, the cover folding axis  64  is located in a line of intersection of the surface areas defined by the lower sides  100  and  102 .  
         [0111]    The wind blocker folding axis  44  and the cover folding axis  64  are preferably placed such that the wind blocker folding axis  44  and the cover folding axis  64  are essentially located one above the other and extend at a distance parallel to one another when a wind blocker  12  is folded onto the cover  16  about the connection folding axis  90  so that the frame support parts  32   a, b  and  34   a, b  as well as the outer connecting supports  36  and  38  are likewise located on top of one another when wind blocker parts  52  and  50  are folded onto one another, as illustrated in FIG. 5.  
         [0112]    Furthermore, the cover  16  is likewise designed such that the frame sections  85   a  and  85   b  are likewise located essentially congruently on top of one another.  
         [0113]    The wind blocker parts  50  and  52  as well as the cover parts  60  and  62  are preferably essentially of approximately the same size and same shape so that in the completely folded state of the inventive wind stop device a stack can be formed, with which two cover parts, namely the cover parts  60  and  62 , are, first of all, located on top of one another and two wind blocker parts  50  and  52  located above one another are located on them.  
         [0114]    In order to place the wind blocker parts  52  and  50  as well as the cover parts  60  and  62  on top of one another, an at least releasable connection between the wind blocker part  52  and the cover part  62  is preferably provided, with which the lower frame support part  32   b  extending in the wind blocker part  52  can be secured to the front frame support part  72   b  extending in the cover part  62  in a releasable manner.  
         [0115]    In contrast thereto, the wind blocker part  50  is preferably securely connected to the cover part  60  via a hinge  104 , the hinge axis of which coincides with the connection folding axis  90 .  
         [0116]    The releasable connection between the wind blocker part  52  and the cover part  62  is preferably brought about via a locking unit  110  which has a locking bolt  114  which can be displaced in a direction  112  parallel to the front frame support part  72   b , is part of the fixing device  24  and serves to fix the wind stop device to the body  10  (FIG. 6). At the same time, the locking bolt  114  is, however, displaceable in the direction of the cover folding axis  64  such that the locking bolt  114  can be brought into or out of engagement with a hook  116  which is held on the frame support part  32   b  and through which the locking bolt  114  extends in the connected state of the wind blocker part  52  to the cover part  62  so that the hook  116  and the locking bolt  114  form a hinge between the wind blocker part  52  and the cover part  62 , the hinge axis of which is located coaxially to the connection folding axis  90 .  
         [0117]    Such a hinge may, however, be formed from the hook  116  and the locking bolt  114  only when the locking bolt  114  is arranged coaxially to the connection folding axis  90  and also the hook  116  is coaxial to the connection folding axis  90  which can be achieved only when the wind blocker parts  50  and  52  as well as the cover parts  60  and  62  are each folded about the corresponding folding axes  44  and  64  to such an extent that they are in their extended position and, for example, the wind blocker  12  and the cover  16  are located on top of one another or at least the lower frame support  32  extends parallel to the front frame support  72 .  
         [0118]    The fixing device  22  also preferably has a locking bolt  118  which can likewise engage in a corresponding recess in the body  10  in order to fix the wind stop device on it.  
         [0119]    In a second embodiment of a wind stop device, illustrated in FIGS.  7  to  10 , those parts which are identical to those of the first embodiment are given the same reference numerals and so with respect to their description reference is made in full to the comments on the first embodiment.  
         [0120]    In contrast to the first embodiment, the cover  16  has a cover frame  70 ′ which is formed merely from the front frame support  72 , the rear frame support  74  and the outer connecting supports  76  and  78  and is thus of a similar construction to the wind blocker frame  30 . For this reason, the front frame support  72  and the rear frame support  74  are provided with the outer connecting supports  76  and  78  so that the cover frame  70 ′ has a uniform frame opening  86 ′, in which the flat material  88  is held so as to be tensioned.  
         [0121]    Thus, the cover frame  70 ′ likewise comprises two C-shaped frame sections  85   a ′,  85   b ′ which adjoin the cover folding axis  64  with their open sides.  
         [0122]    To simplify the folding about the folding axis  64 , the flat material  88  is located in each frame section  85   a ,  85   b  in a surface area, preferably a plane E U , which coincides with the lower sides  100  and  102  of the cover parts  60 ,  62  and the cover folding axis  64  is located in a line of intersection of these surface areas E U .  
         [0123]    As for the rest, the wind blocker  12  comprises two wind blocker parts  50  and  52  and the cover  16  two cover parts  60  and  62  which, as illustrated in FIGS.  8  to  10 , can be folded in the same way and about the same axes as described in detail in conjunction with the first embodiment.  
         [0124]    In the second embodiment, the wind blocker frame  30  and the cover frame  70  are, in particular and in principle, of an identical construction so that in the folded state illustrated in FIG. 10 a uniform picture preferably results.  
         [0125]    A first embodiment of a screen element according to the invention, shown in FIG. 11, which can be used as wind blocker part  50 ,  52  of wind blocker  12  in the wind stop device described before or as cover parts  60 ,  62  of cover  16  of said windstop device, comprises a frame  210  which encloses an area  212  over which a piece of flat material  214  extends.  
         [0126]    The piece of flat material  214  is, as shown schematically in FIG. 12, made from a woven or knitted fabric consisting of inherently stiff wires or fibers  216 , preferably metal wires, and is, therefore, not flexible, but has an inherent rigidity.  
         [0127]    As shown in FIG. 13, in the first embodiment the piece of flat material  214 , which extends in a surface area  218  in the area  212  enclosed by the frame, is bent over at an edge area  220  such that the latter extends transversely to the surface area  218 . This edge area  220  lies in a recess  222  of the frame  210 , which is comprised of two frame parts  224   a  and  224   b , and the recess  222  is provided as free space between these frame parts  224   a  and  224   b  for receiving the edge area  220 .  
         [0128]    The frame parts  224   a  and  224   b  each abut with bearing surfaces  226   a  and  226   b  on the piece of flat material  14  and fix it in a bearing area  28  of the edge area  220 . Starting from this bearing area  228  a bent over area  230  of the edge area  220  extends into the recess  222 .  
         [0129]    The two frame parts  224   a  and  224   b  are preferably provided with further bearing surfaces  232   a  and  232   b , with which they abut directly on one another, and in the area of which a permanent connection between the frame parts  224   a  and  224   b  can be made in many different ways.  
         [0130]    One possibility for a permanent connection in the area of the bearing surfaces  232   a  and  232   b  is that of adhering the frame parts  224   a  and  224   b.    
         [0131]    Another possibility is that of joining the frame parts  224   a  and  224   b  together in the area of the bearing surfaces  232   a  and  232   b  by ultrasonic welding or some other type of welding.  
         [0132]    In the case of ultrasonic welding a precondition is that at least one of the frame parts  224   a  and  224   b  is made of a thermoplastic material so that at least in individual areas a heating-up and softening of the thermoplastic material can be carried out ultrasonically and the two frame parts  224   a  and  224   b  can then be joined to each other due to this softening.  
         [0133]    In a second embodiment of a screen element according to the invention, shown in FIG. 14, the piece of flat material  214  is not bent over at the edge area  220 , but the edge area  220  extends in continuation of the surface area  218  over a frame part  240  of the frame  210  and rests on a surface  242  of the frame part  240 .  
         [0134]    If the frame part  240  is provided with energy directing elements  244  lying over the surface  242 , it is possible by the application of a sonotrode and the action of ultrasound, if the energy directing elements  244  consist of a thermoplastic material, to heat up and soften the thermoplastic material in the area of the energy directing elements  244  so that a plastic melt is formed, into which the edge area  220  of the piece of flat material  214  is then embedded with the wires  216  so that after solidification of the plastic melt the wires are embedded in a positively locking manner in a material agglomeration  246  formed by softening the energy directing elements  244 .  
         [0135]    In a third embodiment of the screen element according to the invention, shown in FIG. 15, the dimensional and inherent rigidity of the piece of flat material  214  is put to advantageous use.  
         [0136]    In this third embodiment, the edge area  220  of the piece of flat material  214  preferably likewise extends in the direction of the plane  218  and is provided with the frame  210  by the material forming the frame  210  being formed on the edge area  220  by injection molding or foaming it around the edge area  220  so that the edge area  220  is embedded in the material forming the frame  210  and a positively locking connection is thus created between the edge area  220  and the material which is injection molded or foamed around it so as to form the frame  210 .  
         [0137]    With this solution, if the material forming the frame  210  is a very soft material, the frame  210  can then make only a slight or insignificant contribution to the stability of the screen element so that the stability of the screen element primarily results from the inherent rigidity of the wires  216  of the piece of flat material  214 .  
         [0138]    In a fourth embodiment, shown in FIG. 16, in order to improve the stiffness of the edge area of the piece of flat material  214 , the edge area is shaped by bending over, for example, wrapping over the edge area  220 , to form a loop  250  which results in an edge rigidity in addition to the inherent stiffness of the piece of flat material  214 .  
         [0139]    This bending of the edge area  220  can be protected solely by a simple sheathing or also by injection molding around it. With appropriate machining of the wires  216 , it is, however, also conceivable to provide solely the bent over edge area  220  as frame.  
         [0140]    In a fifth embodiment, shown in FIG. 17, in a modification of the fourth embodiment, shown in FIG. 16, a piping  252  which contributes towards additional stiffening and stabilization of the edge area is inserted into the bent over edge area  220 .  
         [0141]    In a windstop device as described hereinabove and shown in a further embodiment in FIG. 18 a sixth embodiment of a screen element is used to form the cover part  60 ,  62  of cover  16 .  
         [0142]    However, the sixth embodiment can also be used as the wind blocker part  50 ,  52  of wind blocker  12 .  
         [0143]    In the sixth embodiment of the screen element a stabilizing structure  260  is provided and comprises an outer rim element  262  corresponding with its outer contour to the outer contour of the respective wind blocker part  50 ,  52 .  
         [0144]    The stabilizing structure  260  further comprises a web structure  264  extending within a surface area  266  enclosed by the outer rim element  262  and being connected to the outer rim element  262  such that the web structure  264  provides stability to the outer rim element  262 .  
         [0145]    Preferably, the outer rim element  262  and the web structure  264  are formed as an integral part, for example, by injection molding, such that form stability of the outer rim element  262  is maintained by first webs  268  extending in a first direction  270  and second webs  272  extending in a second direction  274 , with the second direction  274  extending transversely to the first direction  270 .  
         [0146]    Preferably, the first webs  268  extending parallel to the first direction  270  are arranged at a constant distance from each other within surface area  266  and the second webs  272  extending parallel to the second direction  274  are also arranged at a certain distance from each other within surface area  266 .  
         [0147]    In the sixth embodiment first webs  268  and second webs  272  form a grid with all webs  268  and  272  being connected to each other and to rim element  262 . For optimum stability of the stabilizing structure  260  the first directions  270  and second directions  274  extend essentially in the longitudinal directions of rim supports  280 ,  282 ,  284  and  286  which are connected to each other in order to form rim element  262 .  
         [0148]    Preferably, the first and second directions  270 ,  274  extend with respect to the longitudinal direction of rim supports  280 ,  282 ,  284  and  286  at an angle lying in a range of between about 200 and 700 in order to obtain good stabilization of rim element  260 .  
         [0149]    Preferably, first webs  268  and second webs  272  extend as crossovers such as beams or rods or bars or legs between two respective ones of the rim supports  280 ,  282 ,  284  and  286 , preferably between subsequent rim supports  280 ,  282 ;  282 ,  284 ;  284 ,  286 ;  286 ,  280  of said rim supports  280 ,  282 ,  284  and  286 .  
         [0150]    Further first webs  268  and second webs  272  are arranged such that there are wide openings  290  between these webs  268 ,  272  with the sum of the areas of the openings  290  corresponding to more than 90%, preferably more than 95% of surface area  266  enclosed by the rim element  262 . In such a design the web structure  264  is not wind-tight.  
         [0151]    Preferably, the first and second webs  268 ,  272  are interconnected at the points of intersection  292  in order to improve stability of the entire web structure  264 .  
         [0152]    Furthermore, all webs  268 ,  272  of the web structure  264  are made of an inherently stiff material extending without any tension between rim supports  280 ,  282 ,  284 ,  286 .  
         [0153]    The sixth embodiment of the screen element further comprises a piece of flat material  294  with bending slackness which can be fixed to stabilizing structure  260 . One possibility would be to fix an outer edge portion  296  of flat material  294  to rim element  262  of stabilizing structure  260  by glueing or welding.  
         [0154]    In the sixth embodiment shown in FIGS. 19 and 20 fixing of flat material  294  is performed by providing two frame parts, one frame part being rim element  262  and another frame part being cover element  300 , which together form an outer frame  302  as shown in FIG. 22 when fixed relative to each other. Outer frame  302  fixes outer edge portion  296  by clamping.  
         [0155]    Preferably, outer rim element  262 , as shown in FIG. 22, is provided with a groove  304  forming receiving means within which outer edge portion  296  of flat material  294  is held by a protrusion  306  provided on cover element  300 . Protrusion  306  is formed so as to be force-locked within groove  304  when outer edge portion  296  is pressed into groove  304  by protrusion  306 .  
         [0156]    Cover element  300  further comprises an outer cover portion  308  extending over and covering groove  304  and also covering outer rim  262  on its outer side opposite to the side from which web structure  264  extends.  
         [0157]    In the preferred embodiment, outer rim  262  is further provided with an outer edge  310  covered by cover portion  308 , whereas cover portion  308  on its side adjacent outer edge  310  is provided with a protrusion  312  arranged on a side of outer edge  310  opposite to groove  304 , so that when cover portion  308  is mounted on outer rim  262  with protrusion  306  extending into groove  304 , protrusion  312  when abutting on the side of outer edge  310  opposite groove  304  prevents cover portion  308  from movement in a direction which would allow protrusion  306  to move out of groove  304 .  
         [0158]    Consequently, outer rim element  262  and cover element  308  are fixed with respect to each other by form-locking between protrusion  306  and groove  304  and between protrusion  312  and outer edge  310 .  
         [0159]    Outer rim element  262  is further provided with a guiding surface  314  arranged on the side of groove  304  facing surface area  266  enclosed by outer rim element  262  so that flat material  294  is supported by guiding surface  314  so as to extend in a surface  316  defined by guiding surface  314 .  
         [0160]    Furthermore, web structure  264  extends in a surface  318  arranged essentially parallel to guiding surface  314  so that web structure  264  extends on one side of flat material  294 .  
         [0161]    In the preferred embodiment, surfaces  316  and  318  are arranged at such a distance that flat material  294  extends free of contact with web structure  264 , preferably so that there is a free space between web structure  264  and flat material  294 .  
         [0162]    However, it would be possible to arrange guiding surface  314  of outer rim  262  above web structure  264  so as to have the flat material  294  abutting on one side of web structure  264 .  
         [0163]    In the preferred embodiment shown in FIG. 22 flat material  294  is made of a tensionable material so that tensioning of flat material  294  occurs when outer edge portion  296  of flat material  294  is squeezed into groove  304  by protrusion  306  in order to provide a perfect flat optical appearance of flat material  294 .  
         [0164]    Flat material  294 , in particular when used for cover part  60 ,  62 , can be made of air-tight material.  
         [0165]    However, a preferred embodiment provides an air-permeable flat material  294 , in particular made of a woven, knitted or braided fabric or a perforated foil.  
         [0166]    To assemble the screen element according to the sixth embodiment, flat material  290  is disposed on stabilizing structure  260 , and cover element  300  is arranged on a side of flat material  294  opposite the side on which stabilizing structure  260  is arranged.  
         [0167]    By pressing cover element  300  onto rim element  262  of stabilizing structure  260 , flat material  294  is fixed by its outer edge portions  296  being clamped in groove  304  by protrusion  306 , as described above, and being tensioned. Furthermore, cover element  300  is fixed on rim element  262  if protrusion  312  is arranged on a side of outer edge  310  opposite groove  304 .  
         [0168]    As can be further seen from FIG. 21, rim element  262  is provided with grooves  304  on opposite sides so that cover element  300  and flat material  294  can be mounted from both sides.