Abstract:
A novel safety device for the driver&#39;s cabin of a truck, wherein the driver&#39;s cabin demonstrates at least one driver seat ( 10, 16 ) with a first side ( 10 a) facing a side window and a second side ( 10 b) opposite the first side, is suggested. The safety device comprises a safety net ( 20 ), which is spread next to the second side ( 10 b) of the driver seat ( 10 ) at least in the event of a rollover accident. The safety net can be permanently spread next to the driver seat, or it can be rolled up or folded together in the state of rest and only be spread next to the driver seat when needed. The safety net prevents the person sitting on the driver seat from falling to the opposite inner structure of the driver&#39;s cabin when the driver&#39;s cabin rolls over ( FIG. 10 ).

Description:
FIELD OF THE INVENTION 
   The invention relates to a safety device for a vehicle cabin. 
   BACKGROUND OF THE INVENTION 
   A safety device for a driver&#39;s cabin of a vehicle, such as for example a truck, is intended to improve the protection of a driver in the event of an accident is disclosed in patent GB 2 351 711 A. The safety device comprises a safety net, which is pulled in front of the side window of the driver&#39;s door to prevent the driver being thrown from the cabin when the side window is open. Without such a safety device, this can happen in particular when the driver is not seatbelted. 
   SUMMARY OF THE INVENTION 
   Proceeding herefrom, it is the object of the present invention to create another safety device for the driver&#39;s cabin of a truck that will help further improve the safety of the driver and possibly the passenger. 
   When the driver&#39;s cabin tips over, the driver may not only be at risk of being thrown out the open side window, but also of being thrown in the opposite direction, namely into the interior of the driver&#39;s cabin. The driver may then, for example, strike the inner structure of the passenger door, where a relatively long distance of fall can appear because of the large width of a driver&#39;s cabin. 
   In at least one embodiment of the present invention, a safety net may be provided on the side of the vehicle seat, such as a driver&#39;s seat, opposite the side window. Such a safety net may catch the driver at an early point in time, before he/she has transpassed a large height of fall, thereby diminishing the risk of injury. Such a safety net may also prevent the driver from striking any passenger who might be present. 
   As long as the safety net is sufficiently transparent, it is possible to permanently dispose the safety net next to the driver. But in many cases, optimum protection can be achieved only if the safety net essentially extends across the entire cross-section of the driver&#39;s cabin and thus divides the driver&#39;s cabin in the longitudinal direction. In general, drivers will presumably not accept such a nearly complete division of the driver&#39;s cabin. 
   In a first preferred embodiment, the safety net is at rest in the folded state and is unfolded into its protective position only upon a sensor signal. The corresponding sensor can, in particular, be an inclination sensor that measures lateral inclination of the driver&#39;s cabin. 
   In a second preferred embodiment, the safety net has a triangular shape and runs from a maximum width, which is located essentially at the height of the driver seat, to a top end, which is preferably located above the head of the driver. 
   The safety net is preferably held by a rod which runs essentially vertically, the vertically running rod furthermore preferably being rigidly connected to the cabin floor and the cabin ceiling. This type of fastening may have numerous advantages: In the first place, a rod running vertically in this manner can be easily positioned so that it provides ideal protection for the driver. Furthermore, a rod running vertically in this manner can be subsequently built into an already existing cabin, the system thus also being suitable for retrofitting. Finally, such a vertically running rod can also carry other devices, such as steps or a display screen. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a longitudinal section through a driver&#39;s cabin in a first embodiment of the invention; 
       FIG. 2  is a longitudinal section through a driver&#39;s cabin in a second embodiment of the invention in the state of rest; 
       FIG. 3  is the depiction shown in  FIG. 2  viewed from the direction R; 
       FIG. 4  is the depiction shown in  FIG. 2  with the safety device activated; 
       FIG. 5  is the safety device depicted in  FIGS. 2 through 4  in the state of rest; 
       FIG. 6  is the safety device depicted in  FIG. 5  in the activated state; 
       FIGS. 7-9  are schematic illustrations of the unfolding process of the safety net depicted in  FIGS. 2 through 6 ; 
       FIG. 10  is a perspective illustration of a driver&#39;s cabin of a truck having a safety device according to a third embodiment; and 
       FIG. 11  is a fourth embodiment of the invention in a schematic illustration. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  schematically shows the driver&#39;s cabin of a truck as seen from the driver door. The driver&#39;s cabin depicted here demonstrates a driver seat  10  located directly in front of the back wall  19  of the cabin, an instrument panel  11  and a steering wheel  15 . A safety net  20 , which extends from the cabin ceiling  18  to approximately the height of the seat surface of the driver&#39;s seat  10 , is located on the side of the driver&#39;s seat  10  pointing in the direction of the interior of the driver&#39;s cabin (herein called the second side). Here the safety net is embodied as a net made out of a plurality of strings knotted or weaved together, its mesh size being so large that the safety net  20  is sufficiently transparent so that the driver can adequately see outside the right rearview mirror through the safety net  20 . In this embodiment, the safety net  20  is permanently mounted in the position depicted in  FIG. 1 . Here the safety net can be fastened on the cabin ceiling  18 , on the rear wall  19  of the cabin and on the instrument panel  11 . This embodiment is very inexpensive and nevertheless offers a high degree of additional safety for the driver. If the truck tips onto the passenger side, the net will catch the driver and prevent him/her from falling through the driver&#39;s cabin. The disadvantage of this embodiment, however, is that the driver can have a certain feeling of “imprisonment.” A safety net having this geometry is also effective if the driver is unseatbelted. 
     FIGS. 2 to 9  depict an embodiment that offers a similar degree of safety as the first embodiment but which the driver may deem as less constraining. The second embodiment of the invention is shown on the basis of a driver&#39;s cabin as often found in semitrailer trucks in particular. Here two bunks  12 ,  14  are disposed behind the driver&#39;s seat and passenger seat. The rear wall  19  of the cabin may not be available for fastening the safety net  20 . A vertically running rod  22 , which carries the safety net  20 , is therefore provided. 
   FIGS.  2 , 3 , 5  and  7  depict the safety device in its state of rest. In this state of rest, there is no unfolded safety net  20  located on the second side of the driver&#39;s seat  10 . In the state of rest, one arm  24  extends parallel to the vertically running rod  22  upon which it is locked by a locking device  25 . A pivot joint  27  disposed in a lower region of the rod  22  serves for the connection between arm  24  and rod  22 . Signal lines  29  connect the locking device  25  to the body electronics or to a separate inclination sensor (not illustrated). This inclination sensor can, for example, be embodied as an inclination sensor like those currently used for the blocking devices of belt retractors. If the lateral inclination of the driver&#39;s cabin exceeds a predefined critical angle and/or a predefined acceleration limit is exceeded, then a signal is sent to the locking device  25 , which thereupon unlocks the arm  24 . The arm  24  then swings into its horizontal position due to gravitational force. Locking means that lock the arm in this final position can be provided. The arm  24  could also be prestressed against the rod  22  by a spring (not illustrated) so that the arm  24  will more rapidly swing into the horizontal position depicted in  FIGS. 4 ,  6  and  9  after the locking is released. Excessive acceleration is preferably avoided so as to minimize the associated risk of injury, and is also not necessary, because there is usually a relatively large amount of time available to unfold the safety net  20  after a tipping movement has been detected. 
   A guide rail  26  comprising a slide element  28  is disposed on the cabin ceiling  18 . In the state of rest (see  FIGS. 2 and 7  in particular), the slide element  28  is essentially disposed directly above the vertically running rod  22 , which is tightly connected to the cabin floor  17  and cabin ceiling  18 . In this state, the safety net is folded together. If the locking device  25  is now raised, then the arm  24  swings (see  FIG. 8  in particular) into its horizontal position, wherein the front top corner of the safety net  20  is held in position. A pull string  23 , which connects the front top corner of the safety net  20  to the slide element  28 , serves this purpose. During the unfolding, the safety net  20  pulls the slide element  28  into its final forward position depicted in  FIGS. 6 and 9 . The front edge  20   a  of the safety net is stiff so that the unfolded safety net  20  features high stability. As an alternative to the slide element, the front top corner of the safety net or of the pull thread  23  that is fastened here can also be directly connected to the cabin roof. In this case, the safety net  20  cannot be completely folded together on the rod  22 . 
   In the unfolded state of protection, the safety net  20  essentially covers the same cross section as the safety net of the first embodiment so that the protective effect is similar. Since essentially the entire cross section of the driver&#39;s cabin is covered in this case, an unseatbelted driver is also well protected in these two embodiments. 
   In the second embodiment illustrated in  FIGS. 2 to 9 , a sensor unit which checks, at least prior to the release of the locking, whether an object (and as the driver&#39;s arm or leg) is located in the plane of motion of the arm  24 , is preferably present. If such an object is sensed, then the locking is preferably not released. Such a sensor unit can comprise a photoelectric barrier for example. 
     FIG. 10  depicts a third embodiment of the invention. This embodiment will also be explained on the basis of a driver&#39;s cabin that comprises two bunks  12 ,  14  and is suitable for long-distance drives. Here too, the safety net  20  is fastened to a vertically running rod  22  comprising an arm  24 . The arm  24  is permanently in a horizontal position, however, at least during the drive. In order to provide the driver full access to the cabin during his/her breaks, the arm can may be disposed on the vertically running rod so that it swings around a pivot joint so that the arm can be swung into a vertical position manually. It should nevertheless be ensured that the arm is locked in the position illustrated in  FIG. 10  when the engine is running. This can be accomplished, for example, through the presence of a switch which will interrupt the engine ignition if the arm is not locked in its horizontal position. 
   In one example, the safety net  20  may have a triangular shape with the hypotenuse extending diagonally from the end of the arm  24  to the vertically running rod  22 . The dimension of the safety net is chosen in such a manner that it does not impair sight of the driver to the right outside rearview mirror. A confined feeling for the driver, as can occur in the first embodiment, therefore does not arise. In this embodiment, less cross section than in the first two embodiments of the driver&#39;s cabin is covered but it still does result in significantly improved safety compared to the prior art. 
     FIG. 10  illustrates that the vertically running rod  22  can still be used as carrier for other devices, such as steps  30  and a display screen  32 . 
   In the second and third embodiment presented here, transparency of the safety net is dispensable. Here it therefore does not have to be embodied as a knotted net, but can also be embodied as a cloth run or the like. Knotted nets are nevertheless preferred because of the good ratio between weight and load-bearing capacity. 
   It is to be understood that a safety device described here can also be assigned to the passenger seat  16  (see  FIG. 3 ), namely every vehicle seat. In particular, it is also possible to assign a safety net both to the driver&#39;s seat and to the passenger seat. 
     FIG. 11  depicts a fourth embodiment of the invention in a schematic drawing. Here the safety net  20  is rolled up on a spindle  46 . This spindle extends vertically and is disposed approximately at the height of the backrest of the vehicle seat. From the front edge  20   a  of the of the safety net  20 , two pull ropes  49  extend across front deflection rollers  48   c , which are connected to the vehicle interior structure at a front end of the driver&#39;s cabin. Rear deflection rollers  48   b  and first deflection roller  48   a  are connected to the moving piston  42 , which is disposed in cylinder  40 . 
   A pressure pipe  44  is connected to a lower section of the cylinder  40 . This pressure pipe  44  is also connected to the compressed-air system of the brake system of the truck. When the engine of the truck is running, an overpressure, which presses the piston  42  upwards, thus prevails in the lower part of the cylinder  40 . In the normal operating state, the piston  42  is held by the locking device  25 . This locking device  25 , as also described above in the second embodiment, is connected to a sensor, an inclination sensor for example, and releases the piston  42  when the lateral inclination of the driver&#39;s cabin exceeds a predefined value. In this case, the piston  42  moves upwards and pulls on the pull ropes  49 , which pulls on the safety net  20  in turn and unwinds it from the spindle  46 , so that the safety net arrives into position next to the driver or next to the passenger, respectively. 
   The spindle  46  is connected to flat spiral springs whose force counteracts the unwinding of the safety net  20 . The flat spiral springs are of course embodied such that they do not prevent the unwinding of the safety net  20  but only become tensioned from the unwinding. The safety net  20  remains taught as long as the compressed-air system is under pressure. The piston  42  is released after the compressed-air system is shut off, and the safety net  20  is automatically again wound up on the spindle  46  because of the prestressed flat spiral springs. The system thus works in a completely reversible manner. This is particularly advantageous when the driver&#39;s cabin does not tip over after the release of the locking device and the spreading of the safety net thus likewise only occurred as a precaution. No repair at the workshop is necessary to put the safety device described here back into its normal at-rest position. Instead of providing a separate locking device, it is also possible to connect the sensor to a valve and then impinge the lower section of the cylinder with pressure only when the sensor detects a critical inclination. 
   Spindle  46  and cylinder  40  of the fourth embodiment described above can be disposed in a rod  22 , wherein the rod  22  here comprises a longitudinal slot through which the safety net  20  exits. 
   As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles of this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from the spirit of the invention, as defined in the following claims.