Abstract:
This invention relates to an air bag system for accommodation behind a vehicle covering. The air bag system contains an air bag, which advances in a main inflating direction when the air bag system is triggered, and a gas generator for supplying the air bag with pressure gas during triggering of the air bag system. The gas generator and the air bag are connected by a gas distributing duct which extends at least partially at an angle with respect to the main inflating direction of the air bag. In this case, the gas distributing duct is formed of air bag material. Furthermore, the invention relates to a manufacturing process and a triggering process for such an air bag system as well as to a motor vehicle having such an air bag system, of which at least the air bag is arranged on a sliding roof frame part.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of Ser. No. 09/915,149 filed Jul. 24, 2001, now U.S. Pat. No. 6,502,854, which is a continuation of Ser. No. 09/176,941 filed Oct. 22, 1998, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a particular air bag system. Furthermore, the invention relates to a particular air bag system manufacturing process as well as to a particular triggering process for an air bag system. Finally, a motor vehicle having at least one air bag system also forms part of the invention. 
     The invention basically comprises, among other elements, side air bags and roof air bags in an automobile and their housings. 
     2. Description of Related Art 
     European Patent Document EP 97 102 307.2 discloses a side impact protection device for vehicle occupants in which an air bag, in the folded ready condition, is arranged behind a covering part on the roof frame of a vehicle. This is a head gas bag which, while folded in an elongated manner, is situated behind the covering part as long as it is not triggered. In this case, a gas generator is integrated directly in the gas bag and extends maximally along one third of the gas bag. It is a disadvantage in this case that the mounting site of the gas generator is limited. Specifically, if the mounting site is situated in a forward or rearward end area of the gas bag, then an unfavorable inflation performance of the gas bag may result, which may cause the gas bag to reach its inflated condition incompletely or too late. 
     This can be avoided by means of an air bag according to German Patent Document DE 196 42 964.1. This air bag system for a motor vehicle contains an air bag consisting of an inflatable gas cushion, a gas generator for filling the air bag, a gas guiding tube which extends through a partitioned-off area of the air bag and has blow-out openings, a profile strip with a discharge duct constructed therein, in which the air bag, folded in a stack shape, is accommodated, and fastening elements for holding the constructional unit consisting of the profile strip, the air bag and the gas guiding tube. Although, by way of its blow-out openings, the gas guiding tube permits a targeted filling of the air bag when the air bag is triggered, the gas guiding tube and its mounting cause additional expenditures which make the whole air bag system significantly more expensive. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an air bag system in which the air bag can be inflated in a targeted manner without significant additional expenditures. 
     This object is achieved by way of the particularly claimed air bag system, the particularly claimed air bag system manufacturing process, the particularly claimed triggering process for an air bag system and a motor vehicle as particularly claimed. 
     Another problem existing in the prior art is known, for example, from two older German Patent Applications DE 196 04 055.8 and DE 196 32 222.7 by the same applicant as that of the present application. This problem relates to the fastening of the air bag system on a vehicle roof with an integrated sliding roof. A remedy for this problem is provided by the present invention. 
     Preferred and advantageous further developments of individual implementations of the invention will also be apparent. 
     Without limitation, the present invention comprises, in addition to the preferred embodiments indicated in the description and the characteristics and combinations of characteristics indicated in the claims, all concepts, principles and generalizations which a person skilled in the art can easily recognize. Also, the complete contents of German Patent Applications DE 196 04 055.8 and DE 196 32 222.7, European Patent Document EP 97 102 307.2, and German Patent Document DE 196 42 964.1 are incorporated by reference into this application and become part of the disclosure content of this document. 
     As a result of the invention, an air bag system is provided for accommodation behind a vehicle covering. The air bag system contains an air bag which, when the air bag system is triggered, advances into a main inflating direction, and a gas generator for supplying the air bag with pressure gas during triggering of the air bag system. The gas generator and the air bag are connected by a gas distributing duct which extends at least partially at an angle with respect to the main inflating direction of the air bag. In this case, the invention provides that the gas distributing duct is formed of the air bag material. 
     According to the invention, the gas distributing duct, which provides an optimal distribution of the pressure gas from the gas generator and therefore an optimal inflating performance of the air bag, is formed directly of the air bag material. Thus, in contrast to the gas guiding duct of the prior art, no additional parts are required for forming the gas distributing duct. The labor expenditures for manufacturing the gas distributing duct are also not considerable since the gas distributing duct can be constructed directly while manufacturing the air bag in one work step which, as a rule, can take place simultaneously with other machining operations during manufacture of the air bag. 
     The gas distributing duct preferably extends at least essentially transversely to the main inflating direction of the air bag. 
     Although the gas distributing duct can also be mounted on the air bag, it is advantageous and therefore preferred for the gas distributing duct to be constructed integrally with the air bag. As a result, the whole air bag, together with the integrated gas distributing duct, can be manufactured in one operation from the air bag material. 
     In order to achieve a sufficiently stable gas distributing duct, the gas distributing duct is preferably formed by a two-layer or multi-layer air bag material. This may be further developed by forming the two-layer or multi-layer air bag material of the gas distributing duct by foldings of the air bag material. Such foldings can be implemented directly in the continuous machining and manufacturing process. 
     Preferably, the gas distributing duct is formed by welded connections, glued connections, sewn connections or woven connections of two or more layers of air bag material, and gas passage openings are left between the welded connections, glued connections, sewn connections or woven connections. 
     Additional stabilizations in possible critical areas of the gas distributing duct which are highly stressed by the flowing pressure gas may advantageously be achieved by inserted reinforcements. In particular, reinforcements may be placed in the gas distributing duct in the area of the inflow opening of pressure gas from the gas generator and/or in areas in which the gas distributing duct has a curved course. 
     For the accommodation of at least the air bag of the air bag system according to the invention, a suitable space is already made available by a vehicle covering, such as an inside lining and, particularly, a roof lining of a vehicle. In order to ensure that the air bag will not be loose in this space, covering and fastening devices are preferably contained so that the folded air bag can be accommodated in its ready position. Preferred covering and fastening devices contain at least one layer of a nonwoven material or paper by which the folded air bag can be accommodated in its ready position. In particular, materials and constructions are used for the covering and fastening devices which cause no noise such as squeaking. Furthermore, it is preferred to have the covering and fastening devices fixedly connected with the air bag and/or the vehicle covering. Preferably, the covering and fastening devices are glued to the air bag and/or the vehicle covering. This permits a premounting of the air bag or of the whole air bag system on a vehicle covering such as that on a vehicle ceiling. 
     When fastening elements used for the simultaneous fastening of the vehicle covering and the air bag system, or at least the air bag, on other vehicle parts are provided, an easy mounting with a minimal number of parts is permitted if the air bag or the air bag system is not premounted on the vehicle covering, as described above. Also, with premounted units consisting of the vehicle covering and the air bag or air bag system according to the above description, a particularly stable fastening of such constructional units on vehicle parts is achieved, since the air bag or the air bag system are included in the fastening. 
     In a particularly advantageous manner, the gas distributing duct may be arranged on the side of the air bag which advances during the triggering of the air bag system and appears first from behind the vehicle covering. As a result of this further development, the first inflating of the gas distributing duct during triggering of the air bag system can be utilized for opening-up the vehicle covering. This is particularly advantageous because the gas pressure in the gas distributing duct is particularly high initially and therefore easily opens or detaches the vehicle covering so that the air bag itself will then no longer require a large amount of force to emerge through the corresponding opening. The most important advantage is a shorter inflating time of the air bag so that it can have an earlier protective effect. 
     It is also preferred to provide fastening passage holes in the gas distributing duct and/or the air bag itself which are formed by welded connections, glued connections, sewn connections or woven connections and are sealed off with respect to the interior of the gas distributing duct or the air bag itself. Tension folds of the air bag can also be formed by welded connections, glued connections, sewn connections or woven connections. This facilitates the fastening of the air bag, in which case the corresponding fastening passage holes can be produced directly while establishing the welded connections, glued connections, sewn connections or woven connections for forming the gas distributing duct and the gas passage openings. Separate expenditures, therefore, are not required. The same applies to tension folds in the air bag which optimize its shape and inflating performance. 
     Within the scope of the manufacturing process of an air bag system according to the invention, a gas distributing duct is formed in an air bag by a welded, glued, sewn or woven connection of the air bag material, which gas distributing duct extends at least partially at an angle with respect to the main inflating direction of the air bag. Between the welded, glued, sewn or woven connections, gas passage openings are left. As a result, the above-mentioned air bag system or its air bag can be produced and the above-explained advantages are achieved. 
     Reference has also been made to the advantages provided during the manufacturing process of an air bag system when, simultaneously with the welded, glued, sewn or woven connections for forming the gas distributing duct, fastening passage holes and/or tension folds are formed. The fastening passage holes are sealed off with respect to the interior of the gas distributing duct and/or of the air bag, and the tension folds are formed by the welding-together, gluing-together, sewing-together or weaving-together of the air bag material. 
     The same applies to the further development of the manufacturing process according to which, before providing the welded, glued, sewn or woven connection, the air bag material is folded to form the gas distributing duct in order to have two or more layers in the area of the gas distributing duct. 
     For achieving the above-mentioned objects, the invention also provides a triggering process for an air bag system which contains an air bag accommodated behind a vehicle covering. In this process, gas is guided from a gas generator into a gas distributing duct made of air bag material situated behind the vehicle covering. The inflating gas distributing duct has already opened up the vehicle covering at least partially such that the air bag can emerge. The corresponding effects and advantages are described above. 
     A preferred further development of the triggering process is that the inflating gas distributing duct detaches the vehicle covering at least partially from the vehicle parts covered by it so that the air bag can emerge between the vehicle covering and the vehicle parts covered by it. 
     The invention also comprises a motor vehicle with at least one air bag system as mentioned above according to the invention. In such a motor vehicle, the air bag is mounted in a folded condition as a package optionally by covering and fastening devices on a vehicle covering of the motor vehicle. In addition or as an alternative, the air bag can be fastened in a folded-together condition as a package optionally by covering and fastening devices as well as fastening elements, together with the vehicle covering of the motor vehicle, on other parts of the motor vehicle. 
     As mentioned above, the vehicle covering is a prefabricated ceiling of the vehicle. 
     The advantages described above which occur when the air bag is mounted in a folded-together condition as a package, optionally by the covering and fastening devices on a vehicle part, apply to the whole claimed motor vehicle. 
     According to a further preferred embodiment of the invention, the vehicle part is a frame part of a sliding roof. In this case, the air bag or the air bag system may also be accommodated in a housing, for which, for example, the frame part of the sliding roof can be utilized. 
     According to preferred further developments, the frame part of the sliding roof is a side member which extends in the longitudinal direction of the vehicle and on which a side air bag is mounted, and/or the frame part of the sliding roof is a cross member which extends in the transverse direction of the vehicle. An air bag is mounted on the frame part for protection between occupants sitting in the front and the rear or for closing the sliding roof opening. In the latter version, the air bag for closing the sliding roof opening preferably has a T-shaped cross-section relative to the longitudinal direction of the vehicle so that the vertical part of the air bag is used for providing a protective cushion between occupants sitting in the left front and in the right front when the air bag system is triggered. Air bag slide rails can additionally or alternatively be provided along the sliding roof cover slide rails for the air bag for closing off the sliding roof opening, and guiding devices can be provided on the air bag for guiding this air bag in the air bag slide rails during triggering of the air bag system. 
     Finally, the invention contains an air bag system having a gas generator and an air bag, in which case the air bag, with or without a housing, can be mounted on a frame part of a sliding roof. 
     A further development of the above will be described in the context of the motor vehicle according to the invention. Specifically, the air bag is a side air bag and the frame part is a side member which extends in the longitudinal direction of the vehicle. The air bag may be an air bag for protection between sitting occupants in the front and in the rear or an air bag for closing the sliding roof opening. The frame part of the sliding roof may be a cross member which extends in the transverse direction of the vehicle. In a particular embodiment, the air bag for closing the sliding roof opening, in a condition installed in the vehicle and inflated, may have a T-shaped cross-section. The latter can be further developed by providing air bag slide rails and guiding devices on the air bag for guiding the air bag into the air bag slide rails during triggering of the air bag system. The air bag slide rails can be mounted at least essentially along sliding roof cover slide rails. 
     The two German Patent Applications mentioned above (DE 196 04 055.8 and DE 196 32 222.7), also by the present applicant, relate to an inside lining for a vehicle roof for accommodating roof air bag systems. In this respect, as well as with respect to the objects of European Patent Document EP  97  102 307.2 and of German Patent Document DE 196 42 964.1, the present invention provides further improvements and advantageous supplementations and alternatives. To the extent that characteristics from the older applications mentioned above can be combined with the present invention, the contents of the two German Patent Applications DE 196 04 055.8 and DE 196 32 222.7 as well as of European Patent Document EP 97 102 307.2 and of German Patent Document DE 196 42 964.1 are incorporated completely in the present document by reference in order to avoid a direct complete repetition of their contents. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in detail in the following with reference to the drawings. 
     FIG. 1 is a schematic lateral view of a first embodiment of an air bag system with an inflated air bag; 
     FIG. 2 is a schematic sectional view of a second embodiment of an air bag system with a folded air bag accommodated on a vehicle behind a vehicle covering in the form of a vehicle ceiling; 
     FIG. 3 is a schematic sectional view of the second embodiment of an air bag system with a folded air bag accommodated on a vehicle behind a vehicle covering in the form of a vehicle ceiling which is similar to the view of FIG. 2 but at a different point with respect to the sectional plane of FIG. 2; 
     FIG. 4 is a schematic sectional view of the second embodiment of an air bag system with a folded air bag accommodated on a vehicle behind a vehicle covering in the form of a vehicle ceiling which is similar to the view of FIG. 2 but at a different point with respect to the sectional planes of FIGS. 2 and 3; 
     FIG. 5 is a schematic sectional view during manufacturing of the air bag of an air bag system according to the invention; 
     FIG. 6 is a schematic, partially sectional view during manufacturing of the air bag of an air bag system according to the invention with a reinforcement in the gas distributing duct; 
     FIG. 7 is a schematic and enlarged lateral view of a third embodiment of a portion of the air bag and of the gas distributing duct with welded connections; 
     FIG. 8 is a schematic sectional view of a fourth embodiment of an air bag system with a folded air bag accommodated on a vehicle behind a vehicle covering in the form of a vehicle ceiling; 
     FIG. 9 is a perspective schematic view of a portion of an air bag of the fourth embodiment of the air bag system; 
     FIG. 10 is a schematic top view of an embodiment of a sliding roof frame with air bag systems arranged on it; 
     FIG. 11 is a schematic view from below the air bags of the air bag systems of FIG. 10 in inflated conditions; 
     FIG. 12 is a schematic view from the front to the rear of the air bags of the air bag systems of FIG. 10 in inflated conditions; and 
     FIG. 13 is a schematic sectional view of a fifth embodiment of an air bag system with a folded air bag accommodated on a vehicle behind a vehicle covering in the form of a vehicle ceiling. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the individual figures of the drawings, which explain the essence of the invention in detail by way of embodiments, the same or similar parts which have the same or similar effects have the same reference numbers. In addition, the drawings are considered to disclose those characteristics which are not explicitly mentioned or explained in the following description or which do not have reference numbers but are understandable for and can be recognized by a person skilled in the art particularly in conjunction with characteristics described above on the basis of technical knowledge, as a result of their representation. 
     FIG. 1 illustrates a first basic variant of an air bag system  1  with an inflated side air bag as a module with a prefabricated ceiling  3  for a vehicle in a lateral view. FIG. 1 shows the finished side air bag  2  in the inflated condition with welded connections  4 , to which reference will be made in conjunction with FIG.  7 . By the welded connections or weld-ins  4 , a gas distributing duct  5 , which may also be called a pressure distributing duct, and, on its border to the actual air bag  2 , gas passage openings  6  from the gas distributing duct  5  to the actual air bag  2  are produced from the material of the air bag  2 . In addition, fastening passage holes  7  as well as tension folds  8  are produced from the material of the air bag  2 . This can all be implemented in a single operation which, among others, may also contain the folding of the air bag  2  in its ready or mounted condition. 
     A gas generator  9  is mounted laterally on the gas distributing duct  5  which supplies the air bag  2  with pressure gas through the gas distributing duct during triggering of the air bag system. 
     The main inflating direction of the air bag  2  is indicated by the arrow A in FIG.  1 . 
     The schematic sectional representation of a second embodiment of the air bag system  1  in FIGS. 2 to  4  illustrates the housing of the air bag  2  behind a vehicle covering  10  in the form of a vehicle ceiling  11  as well as the covering and fastening of the air bag  2  on the vehicle ceiling  11 . For this purpose, covering and fastening devices  12  are provided which may contain a nonwoven or paper layer  13  as well as fastening elements  14  in the form of clips. The nonwoven or paper layer  13  has the purposes of fastening the air bag  2 , folded in its ready position, to the vehicle ceiling  11 , holding the air bag  2  there in a secure manner and covering the air bag with respect to other vehicle parts, such as the frame part  16 . The clips  15 , which are fitted through mounting holes  17  of the vehicle ceiling  11 , additionally fix the air bag  2  in its position on the frame part  16 , because the fastening passage holes  7  are aligned with the mounting holes  17 . No holes for guiding the clips  15  through have to be prefabricated in the nonwoven or paper layer  13  because the clips  15  can simply be pressed through such materials. 
     The fastening of the air bag  2  to the vehicle ceiling  11  takes place by gluing the nonwoven or paper layer  13  to the vehicle ceiling  11 . Because of this glued connection of the nonwoven or paper layer  13  with the vehicle ceiling  11  constructed as a prefabricated ceiling  3 , during the welding-in of the gas distributing duct  5 , care must be taken to surround all fastening passage holes or clip receiving holes  7  and, as required, all roof holding grip fastening passage holes  18  as well by welding for the purpose of tightness. The gas generator  9  can also be welded in or subsequently glued in, or its connections (not shown) can be welded on. In the event of a crash, the air bag  2  is held by means of the clips  15  which are positioned and adapted to shapes. 
     FIG. 2 is a sectional view of the roof frame. In a positioned manner, the folded air bag  2  is fastened as a package by a covered woven textile, nonwoven, or paper material  13  or the like on the vehicle ceiling  11 . The vehicle ceiling may be constructed as a preform ceiling or a prefabricated ceiling  3 . The pressure distributing or gas distributing duct  5  is situated on the upper end of the air bag  2 . 
     The sectional view of FIG. 2 illustrates that the roof holding grip  19  is also provided with a foot which is constructed as a clip  15 . This clip  15 , by which the roof holding grip  19  is fixed to the frame part  16 , is simultaneously used for fixing the vehicle ceiling  11  and the air bag  2  in their positions on the frame part  16 . FIG. 2 shows the roof air bag which is glued to the prefabricated ceiling  3  or the vehicle ceiling  11  and which is constructed as a side air bag  2 , with the passage or fastening passage hole  7  for the foot clip  15  of the roof holding grip  19 . 
     In general, as a connection possibility or boundary possibility for the further development of the gas distributing duct  5 , the gas passage openings  6 , the fastening passage holes  7  and the tension folds  8 , instead of the indicated welded connection or welding-in, a sewing or taking-in, a gluing or woven connection can be carried out. In the case of the woven connection, two woven layers are woven flatly onto one another and a sealed connection is produced in this manner. 
     FIGS. 3 and 4 are sectional views at different points of the embodiment of the air bag system  1  illustrated in FIG.  2 . FIG. 3 shows a point at which no roof holding grip  19  is present. FIG. 4 shows the positioning of the gas generator  9 . Accordingly, it is in particular also possible to fasten the gas generator  9  on the prefabricated ceiling  3  or vehicle ceiling  11  instead of, as is customary nowadays, screwing it separately to the end of the air bag  2 . 
     As a special characteristic of the invention, FIG. 5 shows a double-walled gas distributing duct  5  during manufacturing of the air bag  2 . The gas distributing duct  5  is produced by a folding of the woven air bag fabric or material, specifically in the case of the illustrated version, by woven air bag fabrics folded over one another in opposite directions. The double wall is an advantageous protection against the high pressure of the gas in the gas distributing duct  5 . In the sectional representation, the folding-over of the woven fabric forms a loop  20  which holds the gas distributing duct  5  open. This is important for the necessary velocity of the gas when emerging from the gas generator  9  and during the passage through the gas distributing duct  5  for entering into the actual air bag  2 . 
     If the opening cross-section of the loop  20 , particularly in the case of a change of direction of the gas distributing duct  5 , for example, in the case of bends, does not remain large enough, an opening device or a reinforcement  21  can be welded on, sewn on, etc., as illustrated schematically in FIG.  6 . FIGS. 5 and 6 only show examples of welding electrodes  22 . Furthermore, FIG. 5 shows a paper attachment  13  which is glued to the folded air bag  2  and later to the prefabricated ceiling  3  or the vehicle ceiling  11 . At the inflow end (not shown) of the pressure or gas distributing duct  5  made of the woven fabric of the air bag  2 , the gas distributing duct  5  may also be correspondingly reinforced by inserts or reinforcements  21  or similar devices. 
     The welding-in and the not-welding-in along the gas distributing duct  5 , as illustrated in FIG. 7, results in the desired gas distribution which, corresponding to results obtained by tests, is designed according to the vehicle and the requirements. In this case, the welding-in/gluing-in/taking-in/weaving  4  is designed such that clip or fastening passage holes  7  are sealed off, longitudinal folds or tension folds  8  for the tensioning of the air bag are formed, outflow or gas passage openings  6  of a corresponding size are formed by means of a single operation such as a welding operation. The loop  20 , which forms the gas distributing duct  5 , is situated above a fastening line of the air bag  2  in the area between the vehicle roof  23  (see, for example, FIGS. 2 to  4 ) and the prefabricated ceiling  3  or vehicle ceiling  11 . 
     Another alternative to the above-mentioned first basic principle consists of mounting the gas distributing or pressure duct  5  at the lower end  24  (compare FIG. 1) of the air bag  2  according to FIGS. 8 and 9. This lower end  24  of the air bag  2  is the side of the air bag  2  which, when the air bag system  1  is triggered, comes out first from behind the vehicle covering  10 , such as the vehicle ceiling  11 ; the gas distributing duct  5  will “hang” on the lower end  24 . As a result, the gas distributing or pressure duct  5  can be used for ripping the covering  10  away which is advantageous for the fast and locally targeted exiting of the air bag  2 . The inflating velocity will also be faster since the air bag  2  can freely unfold already in the inflating stage and must not first open the covering  10  itself and press it away, for example, on a lower edge (not shown). The pressure duct  5  can therefore be folded, for example, under a pretensioning and can be placed at the site where it is simultaneously used for ripping away the covering  10 . Normally, a 100-fold pressure exists in the pressure or gas distributing duct  5  at the start of the ignition. The gas passage and the required folding must be coordinated with one another for optimal functioning. In this fourth embodiment, the air bag  2  is glued in its position by paper  13  in the covering  10 . 
     For the present state of the art, it is typical to accommodate the air bag in a housing with an integrated tube-type pressure supply as a module for accommodation under roof linings (prefabricated ceiling or covering cushion). The present invention, as illustrated by means of the above-explained embodiments, is used for the same purpose but has a simpler construction. 
     In the following, several general principles and embodiments of the invention will be indicated. 
     After the initial folding-together of the air bag  2  for mounting, the folds can be held by a glued-on paper  13  or similar device. Such a paper  13  may protrude over the folded air bag  2 , may be used for gluing the air bag  2  to the prefabricated ceiling  3  and may simultaneously be used as an anti-squeak device with respect to the sheet metal roof  23 . 
     The gas generator  9  or, as an alternative, its connections (not shown) can be welded together during manufacturing of the air bag  2  with the gas distributing duct  5  in a positioned manner. 
     Another accommodation alternative of the roof air bag design is the fastening of the air bags or air bag systems on sliding roof frames. In the case of vehicles without a sliding roof, the solution described in German Patent documents DE 196 04 055.8 and DE 196 32 222.1 can be used. As an expansion of the variant for accommodating two lateral air bags customary today, a variant will be described in the following which has four air bags  2 . 
     FIG. 10 shows a sliding roof frame  25  on which two lateral head air bags  2   a ,  2   b , the air bag  2   c  between the front passenger and the rear passengers, and the air bag  2   d , which closes a sliding roof opening  26 , are fastened. The sliding roof air bag  2   d  is guided on the left and on the right in the sliding roof opening  26  in a slide rail (not shown) in parallel to the sliding roof cover (not shown). In the case of normal pyrotechnical ignition of the air bag system  1 , because of the inflation, this sliding roof air bag  2   d  is pushed like a wall over the sliding roof opening  26 . Preferably, the sliding roof air bag  2   d  is reinforced in its woven fabric such that it protects the occupants also in the event of a rollover. 
     FIGS. 11 and 12 illustrate another special characteristic of this sliding roof air bag  2   d . The air bag has a T-shape together with the center piece  27  which, in the case of the inflated sliding roof air bag  2   d , hangs downward. This has the purpose of protecting the left and the right occupant from one another in the event of a side impact. 
     Before the triggering, the air bags  2   a ,  2   b ,  2   c  and  2   d  are covered by the preform or prefabricated ceiling  3  or the roof cleats (not shown). The inflating of the air bag  2   a ,  2   b ,  2   c ,  2   d  preferably takes place by a folded pressure or gas distributing duct  5  which is mounted at the correct point and is described in conjunction with the first to the fourth embodiment. However, as in the prior art according to German Patent Document DE 196 42 964.1, air bags or air bag systems accommodated in so-called housings may advantageously be used in conjunction with the arrangement on a sliding roof frame  25 , which is also within the scope of the invention, particularly if such housing are simultaneously frame parts of the sliding roof frame  25 . Gas generators (see FIG. 10) for implementing a modular construction can also be accommodated on the sliding roof frame  25 , the prefabricated ceiling  3  or the vehicle ceiling  11 . 
     The structure of a sliding roof frame  25  is therefore suitable for linking and accommodating of head air bags, such as the air bags  2   a ,  2   b ,  2   c  and  2   d . FIG. 13 is a schematic partial sectional view of a vehicle roof  23  with an air bag system  1  and a sliding roof  28 . 
     Several general principles of the invention will now be indicated in connection with the accommodation of air bag systems  1  on a sliding roof frame  25 . 
     Head air bags  2 ,  2   b ,  2   c  and  2   d , including the gas generators  9 , can be integrated on the sliding roof frame  25  of a sliding roof module. 
     By means of the pressure distributing duct  5 , the edge of the prefabricated ceiling  3  of the covering  10  can be ripped loose. The sliding roof air bag  2   d  can be guided on the sliding roof frame  25 , for example, by strips, guided suspensions or general guiding devices on the air bag  2   d  in combination with air bag slide rails. 
     The integration of several functions in one air bag  2   d  is possible. The covering of the sliding roof opening  26  and the sliding roof edges are covered and an intermediate air bag or center piece  27  are molded on for protecting the front occupants against a mutual impact in the event of a side crash. 
     Only for the purpose of completeness, it is indicated that reference numbers  29  and  30  in the figures denote a door weatherstrip or door sealing device of a vehicle door. 
     The invention is not limited to the described embodiments but comprises all implementation possibilities which a person skilled in the art can recognize by means of the present documents, including the disclosure contents of the two German Patent Applications DE 196 04 055.8 and DE 196 32 222.7 as well as European Patent Document EP 97 102 307.2 and German Patent Document DE 196 42 964.1. The present disclosure content is also not limited to a safety device with a roof air bag system. Any other inventions which result from these documents, such as the vehicle ceiling, the air bags, the process for accommodating and triggering the latter, as well as the use of vehicle components for a safety deice having an air bag system, are considered as being disclosed to the described extent.