Abstract:
A glass cover ( 10 ) for a vehicle roof, having an at least partially transparent pane ( 14 ) of safety glass and optionally a support arrangement ( 18 ), which is mounted on the lower side of the pane in the pane edge area by means of a foam block ( 16 ) provided there. The lower side of the pane ( 14 ) is provided with a transparent composite film ( 26 ) having an adhesive film ( 28 ) and a tear- and scratch-resistant shatterproof film ( 30 ) as well as optionally embedded solar cell ( 62 ). The shatterproof film ( 30 ) is affixed on the center area of the lower side of the pane by means of the adhesive film ( 28 ), the film being incorporated into the foam block ( 16 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a glass cover for a motor vehicle roof with a pane of safety glass which is at least partially transparent, a carrier arrangement which is attached to the bottom of the pane in the edge area of the pane by means of peripheral foaming, a transparent film composite which is located on the bottom of the pane and is formed of an adhesive film and a tear-resistant and scratch-resistant fragment protective film,the protective film being cemented to the central area of the bottom of the pane by means of the adhesive film, and the edge area of the pane being enclosed in a peripheral foam, and a process for producing the same. 
     2. Description of Related Art 
     A glass cover of the above mentioned type which is additionally provided with solar cells is known, for example, from published German Patent Application DE 43 23 140 A1. A cover on the bottom is foamed into an enclosing frame with a very narrow edge area so that when the glass pane breaks the cover with the glass fragments can fall into the vehicle interior. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to devise a glass cover, with or without a solar function, for a motor vehicle roof which offers protection to the passengers and to the vehicle interior that is as good as possible when the glass cover breaks and is still easy to produce. Furthermore, the invention also seeks to provide a corresponding production process. 
     This object is achieved in accordance with the invention by a glass cover of the initially mentioned type in which the film composite, in the edge area, is provided with perforations for passage of the foaming mass, and by a corresponding process in which a transparent film composite which has an adhesive film and a tear-resistant and scratch-resistant fragment protective film being affixed in the central area on the bottom of an at least partially transparent pane of safety glass by means of the adhesive film, the edge area which has a tear-resistant and scratch-resistant fragment protective film, but no adhesive film, is embedded into peripheral foam which is applied to the bottom of the bottom of the pane in its edge area, and the adhesive film-free edge area of the film composite is anchored by means of the perforations provided there for passage of the peripheral foaming mass in the peripheral foam. 
     In these approaches according to the invention, it is advantageous that, when the glass pane breaks, on the one hand, the fragments of the broken glass pane remain suspended on the protective film composite, and on the other hand, that the protective film composite is securely joined to the carrier arrangement in the edge area, the protective film composite no longer being flexurally stiff, but like a collecting net which is securely clamped on the edges, being held in place in the cover. In this way, the glass fragments can be prevented from reaching the vehicle interior, passengers can be prevented from being thrown through the broken glass to the outside, articles from the outside can be prevented from being able to penetrate through the broken pane into the interior or the interior is prevented from being freely accessible when the glass pane is destroyed in case of a burglary. 
     The invention is explained in detail below, by way of example, with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view through a side edge area of a glass cover in accordance with the invention; 
         FIG. 2  is a perspective view of the film composite which is used in the manufacture of the cover; 
         FIG. 3  shows a section similar to  FIG. 1  before cementing the film composite on and peripheral foaming; and 
         FIG. 4  is a view similar to  FIG. 1 , but showing an embodiment of a glass cover provided with solar cells. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a first embodiment of the glass cover  10  which is designed for closing or selectively clearing an opening in a fixed roof skin. It can be, for example, the cover of a sliding roof, sliding and lifting roof, raising roof or spoiler roof or also a fixed roof window. The glass cover  10  comprises a transparent glass pane  14  which is provided with peripheral foam  16  (for example, polyurethane foam) in its edge area, by means of which, preferably, a carrier arrangement  18  made, for example, as an inside cover sheet is attached in the edge area of the pane  14  to its bottom. The inside cover sheet  18  is used as a carrier arrangement for the glass pane  14  in order to join it to an displacement mechanism (not shown) for the cover  10 , which can be of any conventional design. On the outer periphery of the foam  16 , there is a seal  20  to prevent penetration of moisture into the vehicle interior  22  when the cover  10  is closed. Furthermore, in the edge area of the pane  14 , on the bottom in the area of the foam  16  or of the inside cover sheet  18 , there is a glass filter in the form of printing which is used as nontransparent visual protection to cover the peripheral foam  16  and the inside cover sheet  18  from above. 
     The glass pane  14  is preferably made from thermally prestressed single-pane safety glass. 
     In its central, transparent area, the bottom of the pane  14  is laminated or cemented to a film composite  26 , this central area extending as far as the inner edge of the glass filter  24 . The film composite  26  is provided on its top, i.e., on the side facing the pane  14 , with an adhesive film or an adhesive layer  28  which is used to affix the underlying protective film  30  to the pane  14  in its central area. The protective film  30  is made to be tear-resistant and scratch-resistant. The film composite  26 , with respect to its base surface, is smaller than the glass pane  14 , but larger than its central transparent area. 
     The inside cover sheet  18  is attached to the glass pane  14  by means of the peripheral foam  16  in which they are embedded. In doing so, the edge area  50  of the film composite  26  which is provided with numerous perforations  52  is embedded into the peripheral foam  16  at the same time. The foam mass passes through the perforations  52 , and thus, nondetachably embeds the film composite  26  into the peripheral foam  16  by form-fit. Between the edge area  50  and the area of the film composite  26  which is affixed to the central area of the pane  14 , there is preferably a tension relief fold  42  which, among other things, prevents the cement connection of the film composite  26  in the central area of the glass pane  14  from being exposed to a tensile load by the attachment of the edge area  50  to the peripheral foam  16  when the cover  10  is, for example, elastically deformed by the forces which occur in high speed driving. In this way, the service life of the cover  10  can be increased. 
     Prior fixing or additional fixing of the edge area of the film composite  26  to the inside cover sheet  18  can take place by means of a screw connection or in some other mechanical way, for example, by means of a clamp connection. 
     The described construction is used to ensure that, even when the glass pane  14  breaks, a certain mechanical integrity of the cover  10  is maintained by the film composite  26 , even with the pane  14  broken, remaining clamped in its edge area  50  to the cover frame which is formed by the peripheral foam  16  and the inside cover sheet  18 , which are also preserved with the glass pane broken. In doing so, the film composite  26  loses its flexural stiffness, but maintains the cover  10  in place and thus can prevent, on the one hand, passengers from being thrown to the outside through the broken pane  14 , and on the other, fragments of the pane  14  or articles being able to penetrate from the outside into the interior  22 . Furthermore, the film composite  26  provides for a certain burglary protection in the case of intentional destruction of the glass pane  14 . The fragments of the broken glass pane  14  remain suspended on the film composite  26  as a result of the adhesive action of the adhesive film  28 . 
     As shown in  FIG. 2 , the adhesive film-free edge area  50  is provided with perforations or openings  52  which are distributed essentially regularly over the edge area  50 . 
     Proceeding from the state which is shown in  FIG. 3 , first the film composite  26  is affixed to the bottom of the pane in the central area of the glass pane  14  by means of the adhesive layer  28 . The edge area  50  of the film that is free of adhesive is therefore not joined to the glass pane  14 . Then, the glass pane  14  which is affixed to the film composite  26 , in this way, is placed in a conventional foaming tool and a suitable material, for example polyurethane, foamed about the edge area in order to attach the inside cover sheet  18  to the glass pane  14 , the foam material travelling through the perforations  52  so as to, in this way, anchor the protective film  30  in the peripheral foam  16 . In doing so, the anchoring of the protective film  30  can be additionally reinforced by mechanical attachment of the edge area  50  of the film composite  26  on the inside cover sheet  18 . 
     The adhesive film is preferably a polyvinylbutyral film (PVB film) or a transparent polyurethane film (PU film), while the protective film  30  is preferably a plastic film which is coated to be scratch-proof, preferably a polyethylene terephthalate film (PET film) which is coated with polysiloxane. 
       FIG. 4  shows an embodiment in which the above described safety concept is applied to a solar cover, the bottom of the glass pane  14  being provided with a solar cell film composite  60  which has a plurality of solar cells  62  that are electrically interconnected and which are located between two hot-melt adhesive films  64 ,  66 , which are made, preferably, of ethylene-vinyl acetate copolymer (EVA). The solar cell film composite  60  is attached to the bottom of the glass pane  14  by means of the upper hot-melt adhesive film  64 . The protective film composite  26  is attached by means of the adhesive film  28  to the solar cell film composite  60  on the bottom hot-melt adhesive film  66 , and thus, to the glass pane  14 . 
     In the edge area  50  which is free of the adhesive film, the protective film composite  26  is anchored as in the embodiment shown in  FIGS. 1  to  3 , by means of the perforations  52  in the peripheral foam  16 . Between the area which is anchored in the peripheral foam  16  and the area of the protective film composite  26  which is affixed to the solar cell film composite  60 , there is a relief fold  42  to prevent delamination with the pane  14  intact as a result of tensile loading of the adhesive connection between the protective film composite  26  and the solar cell film composite  60  which could occur as a result of the anchoring of the area  50  of the protective film composite  26  in the peripheral foam  16 . 
     When the glass pane  14  breaks, the protective film composite  26  which is anchored in the peripheral foam  16  prevents fragments of the pane and the solar cell film composite  60  from falling in or out, and thus, protects especially the vehicle interior and the vehicle passengers. 
     In one modified embodiment, the lower hot-melt adhesive film  66  of the solar cell film composite  60  can be omitted so that the adhesive film  28  of the protective film composite  26  is cemented directly to the solar cells  62  or the upper hot-melt adhesive film  64  of the solar cell film composite  60 .