Abstract:
A perforated fabric diffuser and perforated cushion deflector are sewn inside an outer shell, thus forming a diffuser system within an airbag. The diffuser contains a plurality of openings along a folded edge. The deflector contains a wall defining at least one orifice for attenuating gas flow upon airbag activation. The airbag contains an inlet that fluidly communicates with the deflector and diffuser upon airbag activation. The outer shell is preferably sewn in such a manner as to maintain a plurality of individual cell areas. The fabric diffuser system is disposed within the outer shell such that the diffuser openings are positioned generally over the individual cells. During deployment, the diffuser system thereby functions to facilitate substantially even inflation throughout the airbag.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to safety restraint systems using airbags and particularly to an airbag containing a perforated cloth diffuser and a perforated cushion deflector. A preferred configuration facilitates even deployment of a head side airbag for protection of vehicle occupants from side impact. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     As the automobile has developed, so have methods of ensuring passenger safety. Several methods of safety restraint systems have emerged during this development, including the airbag. Since the introduction of the airbag various degrees of implementing it have emerged including use in protecting passengers from side impact scenarios. To achieve this, vehicle designers have placed airbag systems in a number of locations including passenger seats, vehicle doors and vehicle roof frames. Various methods of improving airbag performance have also been developed. One example, pertinent to the present invention, is the use of a cylindrical metal diffuser that facilitates even deployment or inflation of the airbag. 
     It is an object of the present invention to make a significant improvement over side impact airbag systems through implementation of an improved diffuser system. Although effective, traditional metal diffusing systems often tend to be relatively expensive and may require an increased amount of packaging space. This has an overall effect of limiting the areas wherein diffused airbag systems can be implemented. The present invention replaces the traditional metal diffuser systems with a fabric diffuser. The fabric diffuser offers the same performance as the traditional diffusers, however, it boasts distinct advantages. Initially, a fabric diffuser is both lightweight and cost effective. Manufacture of a fabric diffuser is also less complicated than that of a metal diffuser. A more significant advantage is that fabric diffuser systems in accordance with the present invention have improved packaging characteristics over traditional metal diffusers and can disperse gas rearwardly into the cushion. A fabric diffuser, in contrast to a metal diffuser, can be tightly folded with the overall airbag in its initial packaging. As a result, more options are open to designers in locating airbag systems. 
     An airbag of the present invention comprises a sewn outer shell, and a diffuser system, to include a perforated fabric diffuser and a perforated cushion deflector, disposed within the sewn outer shell. As a result of the advantages described above, the airbag can be inconspicuously packaged in the upper trim running a distance along the front and rear passenger windows. The sewn outer shell is preferably sewn in such a way as to form individual cell areas. In a preferred embodiment, the diffuser incorporates a series of openings along its edge that are located at an area generally above each of the individual cells. Upon deployment of the airbag, the inflation gas initially inflates the diffuser system. The diffuser system then channels the gas to the individual cells, causing the airbag to be evenly inflated. Such a system offers a significant degree of protection for both front and rear passengers. The present airbag is particularly useful as a head side airbag, but not however thereby limited. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial cut-away side view of a head side airbag in accordance with the present invention; 
         FIG. 2  is a top view of an unsewn perforated fabric diffuser pattern in accordance with the present invention; 
         FIG. 3  is a top view of an unsewn perforated fabric cushion deflector in accordance with the present invention; 
         FIG. 4  is a schematic view of a vehicle passenger compartment with an undeployed head side airbag in accordance with the present invention; and 
         FIG. 5  is a schematic view of a vehicle passenger compartment with the head side airbag deployed in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is primarily directed at airbag or vehicle occupant protection systems and more specifically to improving the adaptability and performance of such systems through the use of a diffuser system. 
     With reference to  FIG. 1 , the side view of a head side airbag  10  (also referred to as a cushion) is displayed. An outer shell  12  is sewn in such a manner as to form an interior  14  and two portions,  16  and  18 , each having a plurality of individual cells  20 , and an inlet  22 . Internal to the sewn outer shell is a fabric or cloth diffuser  24 . The fabric or cloth diffuser  24  has a series of openings  26  along its edges and in a preferred embodiment, may also include an inlet or gas entry orifice  22 ′ in lieu of an inlet on the airbag. The outer shell  12  is constructed in such a manner as to form a first plurality of tab portions  28  which are used to attach the airbag  10  to a vehicle (best shown in FIGS.  4  and  5 ). Additionally, a strap  30  is sewn to a corner of the airbag  10  and attached to the vehicle structure thereby stabilizing the forward portion of the airbag  10  during operation. 
     The fabric or cloth diffuser  24  is formed from first unsewn pattern  32 , shown in FIG.  2 . The first unsewn pattern  32  includes a plurality of round holes or perforations that upon the folding of the first unsewn pattern  32  form the openings  26  extending across a portion of the length of the airbag  10 , a second plurality of tab portions  36 , and a first set of inlet halves  38 . The cushion deflector  40  is formed from a second unsewn pattern  42 . The second unsewn pattern  42  preferably includes a cloth wall  44  defining at least one gas flow attenuating orifice  46  used to balance the amount of gas dispersed between the forward and rearward portions of the airbag  10 . Additionally, upon airbag assembly, orifices  47  of the cushion deflector  40  are aligned with openings  26  and thereby provide fluid communication between the fabric or cloth diffuser  24  and the cushion deflector  40 . A third plurality of tab portions  48  extend from opposing sides of the second unsewn pattern  42  for reinforcement of the first plurality of tab portions  28 . If desired, a second set of inlet halves  50  are provided at opposite ends of the cushion deflector  40  and upon airbag assembly also preferably define a gas entry orifice  22 ″. 
     When assembling the airbag  10 , the perforated cushion deflector  40  or the second unsewn pattern  42  is folded in half along a lateral axis “A” such that the third plurality of tab portions  48  on opposing sides of the second unsewn pattern  42  align with one another and the second set of inlet halves  50  align with one another. The folded second unsewn pattern  42  is sewn in between the folded fabric or cloth diffuser  24  thereby orienting the wall  44  generally transverse to the length of the airbag  10  or diffuser  24  (or to the gas flow), as shown in FIG  1 . The first unsewn pattern  32  is folded in half along a longitudinal axis “B” such that the second plurality of tab portions  36  on opposing sides of the first unsewn pattern  32  align with one another and the first set of inlet halves  38  align with one another. As shown in  FIG. 1 , the folded first unsewn pattern  32 , with the folded second unsewn pattern  42  positioned within first unsewn pattern  32 , is sewn in between first and second panels  52  and  54  of the outer shell  12  so that the upper edge  33  of the folded first unsewn pattern  32  is sewn coincident with the upper edge  11  of the outer shell  12 . The airbag  10  is preferably supported by a plastic cartridge or plastic interior molding (not shown), that is in turn supported by the roof frame  56 . A protective cover (not shown) preferably envelopes the airbag  10 . The first and second panels  52  and  54 , respectively, of the outer shell  12  actually include the first plurality of tab portions  28  which overlap the second plurality of tab portions  36  of the fabric or cloth diffuser  24  and the third plurality of tab portions  48  of the cushion deflector  40  thereby reinforcing the mounting tabs  28  for attachment to the vehicle. 
       FIG. 4  depicts the head side airbag  10  mounted in a vehicle passenger compartment  64  with the airbag  10  in its uninflated state. The airbag  10  is mounted to a roof frame  56  opposite a vehicle floor  60 . As shown in  FIG. 5 , a vehicle  62  has a passenger compartment  64  including a forward boundary  66 , a rearward boundary  68 , sides  70 , wherein each respective side  70  contains a door  72 , a side window  74 , a plurality of pillars  76 , and a roof frame  56 . Additionally, the strap  30  is attached to both the airbag  10  and a first pillar  78 . An inflating mechanism or airbag inflator  80 , manufactured as known in the art, is also attached to the airbag  10  in fluid communication with inlet  22 , and mounted to the roof frame  56 . Upon a crash event, the inflating mechanism or airbag inflator  80  activates and the airbag  10  is thus deployed, as shown in FIG.  5 . Stated another way, when triggered, the inflating mechanism or airbag inflator  80  releases gas into inlet  22  thereby inflating the airbag  10 . The fabric or cloth diffuser  24  and the cushion deflector  40  taken together form a diffuser system  82 . The diffuser system  82  is initially inflated and directs the gas flow via the openings  26  into the individual cells  20  of the airbag  10 . Importantly, gas flow entering inlet  22  and traversing through the fabric or cloth diffuser  24  is attenuated as it encounters the wall  44  and the attenuating orifice  46 , thereby dispersing the gas flow across the airbag  10  in a substantially uniform fashion. As shown  FIGS. 1 ,  3  and  5 , the wall  44  is at least partially laterally transverse to the gas flow entering inlet  22 , or transverse to the lengths of the fabric or cloth diffuser  24  and the airbag  10 . The strap  30  functions to limit forward inward movement of the airbag  10  during the deployment process. Upon deployment, the airbag  10  aids in protecting the occupants by substantially covering the side windows  74  of the passenger compartment  64 . 
     A stitch  86  is best shown in FIG.  1  and runs along the periphery of the airbag  10  to integrate the airbag components and to also define the sides of the cells  20 . As shown in  FIG. 1 , the fabric or cloth diffuser  24  and the cushion deflector  40  are sewn in between the first and second panels  52  and  54  of the outer shell  12  such that stitch  86  integrates the fabric or cloth diffuser  24  and the cushion deflector  40  within the sewn outer shell  12 . As described above, inlet or gas entry orifice  22 ′,  22 ″ is formed by sewing the first set of inlet halves  38  of the fabric or cloth diffuser  24  together, and/or, by sewing the second set of inlet halves  50  of cushion deflector  40  together. When both the first set of inlet halves  38  and the second set of inlet halves  50  are employed, for improved strength for example, the second set of inlet halves  50  are placed in an aligned and overlying relationship to the first set of inlet halves  38  prior to sewing within the first and second panels  52  and  54  of the outer shell  12 . The airbag  10 , and therefore the outer shell  12 , the fabric or cloth diffuser  24 , and, for example, the cushion deflector  40  are formed from nylon or other materials known for their use in airbags. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not regarded as a departure from the scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.