Abstract:
An airbag assembly includes an airbag, an inflator for inflating the airbag, a cover and a base plate. The base plate attaches to the cover such that the base plate is secured on each edge of the base plate and is prevented from detaching. The base plate and cover do not require fasteners or removable pieces. The base plate comprises a bendable tab. The bendable tab is configured to bend over an edge of the cover and secure to the cover by a lip on an end of the bendable tab.

Description:
BACKGROUND  
       [0001]     The present invention relates generally to the field of airbag modules and base plate attachments.  
         [0002]     A conventional module for housing an airbag module in a vehicle has a cover or deployment door which attaches to a housing or base plate in which an air bag and inflator are housed. Commonly, a plurality of threaded studs extend from the base plate about its mouth and the cover has corresponding complementary holes which mate with the studs.  
         [0003]     Conventional attachment designs may include rivets, rings, or rigid hooks to connect the base plate and cover. Other conventional airbag systems require the use of two separate base plates, which increase the costs associated with manufacturing the airbag system.  
         [0004]     One drawback of such conventional designs is that the requirement of extra fasteners, rigid hooks or additional base plates increases the overall weight of the airbag module, cost and the difficulty in assembling the module.  
         [0005]     Another drawback of using threaded studs to retain a cover to a base plate is that the studs can be inadvertently cross-threaded during assembly. The studs often require checking in order to verify proper assembly. Furthermore, the deployment of an airbag can be modified when the cover separates from the base plate during deployment, which varies the restraint performance from a designed and expected performance.  
         [0006]     Additional drawbacks exist when utilizing fasteners to secure an air bag cover. For example, threaded fasteners are susceptible of loosening from vibration as a vehicle travels over a bumpy road and therefore require use of a thread binding agent or a lock washer to prevent loosening. This further increases the number of parts, complicates the assembly, and adds to cost and time required for assembly. As a result, such systems for attaching a cover to a base plate tend to be less feasible when constructing air bag modules for use in high volume and low cost applications.  
       SUMMARY  
       [0007]     One embodiment of the invention relates to an airbag assembly. The airbag assembly comprises a base with a main plate portion and a bendable tab, a cover attachable to the base, an airbag stored between the cover and the base, and an inflator configured to inflate the airbag. The bendable tab is configured to attach to the cover.  
         [0008]     According to another embodiment of the invention, a base for an airbag module is provided. The base includes a bendable tab that is configured to attach to a cover for an airbag.  
         [0009]     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     These and other features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.  
         [0011]      FIG. 1  is an exploded side view of an airbag module.  
         [0012]      FIG. 2  is a perspective view of an airbag assembly according to an embodiment of the invention.  
         [0013]      FIG. 3  is a top perspective view of a base plate.  
         [0014]      FIG. 4  is a detail view of a tab.  
         [0015]      FIG. 5  is another detail view of the tab.  
         [0016]      FIG. 6  is a detail perspective view of a tab on the base plate.  
         [0017]      FIG. 7  is a cross-sectional view of the cover taken along line A-A of  FIG. 2   
         [0018]      FIG. 8  is another cross-sectional view of the cover taken along line B-B of  FIG. 2 .  
     
    
     DETAILED DESCRIPTION  
       [0019]     Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.  
         [0020]      FIG. 1  discloses an airbag module  10  for housing an airbag according to one embodiment of the present invention. The airbag module  10  comprises an airbag  18 , a cover  20  and a base plate  30 . The base plate  30  is configured to attach to the cover  20 , when the airbag module  10  assembled. The airbag module  10  may also include an inflator  15 . The inflator  15  provides the inflation gas to inflate and deploy the airbag during a collision.  
         [0021]     The inflator  15 , shown in  FIGS. 1 and 2 , may comprise a gas generant or propellant in order to provide inflation gas to the airbag  18 . In addition, the inflator  15  may include a decomposing type material as the source of the pressurized gas for the airbag  18 . The inflator  15  may include an igniter or initiator assembly (not shown). The igniter receives a signal from a controller in order to initiate operation of the inflator  15  when the controller determines a collision is occurring.  
         [0022]     The airbag  18  is folded in the airbag module  10  in the uninflated state. The airbag  18  connects to a retainer (not shown) to retain the airbag  18  to the base plate  30 .  
         [0023]     The airbag module  10 , as shown in  FIG. 1 , may be mounted in the steering wheel of the vehicle or other suitable location. The airbag module  10  is positioned within the steering wheel of the vehicle in order to protect a driver in a collision, specifically a frontal collision. However, the airbag module  10  may be mounted along the dash, in a door, or any other suitable location for protecting a passenger or driver of a vehicle.  
         [0024]     The cover  20  is generally formed of a plastic material, such as a soft resin, or any other suitable material. The cover  20  must be able to withstand any wear and tear derived from its position in the cabin of a vehicle and must also be able to break open upon deployment of the airbag  18 .  
         [0025]     The cover  20  is attached to the base plate  30  such that an open area is created between the cover  20  and the base plate  30 . The airbag  18  is stored, in the uninflated state, in the open area between the cover  20  and the base plate  30 . The cover  20  forms the barrier between the airbag  18  and the inside of the vehicle passenger cabin area. For example, the cover  20  may form the center portion of a steering wheel.  
         [0026]     The cover  20  includes an interior surface  21  that is adjacent the stored airbag  18  and away from the vehicle passenger cabin area. The cover  20  additionally includes side walls  22  that extend up from the interior surface  21  and create the open area or space for the airbag  18  and inflator  15 . The side walls  22  end at edges  25  that are generally flat.  
         [0027]     The airbag module  10  is mounted to the vehicle by the base plate  30 . The base plate  30  holds the uninflated airbag  18  cushion in the open space between the cover  20  and the base plate  30 .  
         [0028]     The base plate  30  can be made of metal. In addition, the base plate  30  should be of sufficiently high strength such that the base plate  30  can withstand the forces from a collision and from the inflation of the airbag  18 .  
         [0029]     The base plate  30  of an airbag module  10  comprises a main plate portion  31  in a generally square plate shape with edges  35  as can be seen in  FIG. 3 . An opening  34  is formed at the center of the main plate portion  31  for inserting an inflator  15 . Further, bolt through-holes  42  can be positioned at the periphery of the opening  34  for mounting the inflator  15  and/or the air bag. Mounting holes (bolt passing holes)  44  may also be disposed in the main plate portion  31  for mounting the base plate  30  and, thus, the airbag module  10 , to the vehicle.  
         [0030]     The base plate  30  includes a plurality of tabs  36  on edges  35  of the main plate portion  31 , as shown in  FIG. 3 . The tabs  36  are configured to be bendable. Each tab  36  includes a bendable portion  37  that folds or bends back from the surface of the main plate portion  31  at a crease portion  38 , shown in  FIG. 4 . The tab  36  is generally planar with the main plate portion  31  of the base plate  30  when the tab  36  is in a starting, or original, position, such as shown in  FIG. 3 . When the tab  36  is attached to the edge  24  of the cover  20 , the bendable portion  37  of the tab  36  is bent at an angle less than 90° from the main plate portion  31 . This allows for the tab  36  to securely attach over the edge  24  of the cover  20 . The tab  36  is bent or positioned such that it lies against the edge  24  of the cover when the base plate  30  is attached to the cover  20 .  
         [0031]     The tab  36  is configured in a “T” shape, with a “T” section  26   b  and two extending ends  26   a  that are perpendicular to the bendable portion  37 . The “T” section  36   b,  with ends  36   a,  is bent 90° relative to the plane of the base plate  30 . This is to ensure that the flange  27  will be positioned with the base plate  30  during deployment of the airbag  18 .  
         [0032]     Tab  36  fits into a corresponding notch  28  in flange  27 . A flat surface  54  of the flange  27  is adjacent the inside surface  33  of the base plate  30 . The tabs  26  bend around the top of the flange  27  and press against the top area  56  of the flange  27 . The ends  36   a  of the tab  36  press against the upward extending portion  29  of the flange  27 .  
         [0033]     In the embodiment shown in  FIG. 2 , the base plate  30  includes a plurality of tabs  36 , such that each edge  35  of the base plate  30  includes at least one tab  36 . This configuration, having an attachment in every direction, can prevent the cover  20  from detaching from the base plate  30 . Of course, it will be recognized that any number of tabs  36  can be used, such as one, or any other suitable amount.  
         [0034]     A lip  39 , as shown in  FIGS. 4 and 5 , is positioned at an end of the bendable portion  37 . The lip  39  curves downward toward the cover  20  such that the lip fits over the receiving edge  24  of the cover  20 . The tab  36  can also fit over a flat portion  25  of the edge  24 , as can be seen in  FIG. 5 . The lip  39  curves downward from the bendable portion  37  at an angle of approximately 90°.  
         [0035]     When the base plate  30  and cover  20  are assembled, a user can lift up or bend back the bendable portion  37  of the tab  36  such that the base plate  30  can fit into position in the cover  20 . The tab  36  is then released, allowing for the bendable portion  37  to return toward its original position and fit over the edge  24  of the cover  20 .  
         [0036]     The base plate  30  can further include a receiving edge portion  40  positioned along an edge  35  of the main plate portion  31 . The receiving edge portion  40  is configured to receive a flange  27  from the cover  20 . The receiving edge portion  40  is composed of a thickness configured to slide under the flange  27 . The flange  27  slides or fits over the receiving edge portion  40 , securing the cover  20  to the base plate  30 . The flange  27  extends up from the edge  24  of the cover  20  by an upward extending portion  29 . The edge  35  of the receiving edge portion  40  abuts the upward extending portion  29  of the cover  20 .  
         [0037]     The base plate  30 , according to another embodiment, can be composed of any suitable material such as, for example, a high strength resin. Further, the base plate  30  can comprise any shape, such as oval, round, rectangular, etc. In addition, the position and number of mounting holes  44  and bolt through-holes can vary.  
         [0038]     In another embodiment, the position and number of tabs  36  and receiving edge portions  40  may vary as suitable for the airbag module  10 . According to another embodiment, the lip  39  can extend down from the bendable portion  37  of the tab  36  at any angle suitable for fitting over the edge  24  of the cover  20 .  
         [0039]     The “z” position of the module  10  is maintained for the base plate  30  by the top surface area of the cover  20 . In other words, the height of the walls  22  determines and maintains the “z” position of the module  10 .  
         [0040]     The “x” position is made by utilizing an internal horizontal rib  92  in the cover  20 , as shown in  FIG. 8 . The horizontal rib  92  is configured to have dimensions equal to the dimensions of one of a base plate notch  45 . The rib  92  fits in the notch  45  to maintain the module in the x direction.  
         [0041]     The “y” direction is made by using a vertical internal rib  94  in the cover  20 . The vertical rib  94  has dimensions equal to the dimensions of one of the corresponding base plate notches  45 . The vertical rib  94  fits in the notch  45  and keeps the module  10  in the proper position by preventing any movement in the y direction.  
         [0042]     Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. It will be recognized that any combination of embodiments may be utilized. The scope of the present invention is to be defined with reference to the following claims.