TECHNICAL FIELD  
         [0001]    The present invention relates to inflatable restraint modules, and in particular to a mechanism for interlocking an instrument panel to an inflatable restraint module.  
         BACKGROUND OF THE INVENTION  
         [0002]    An inflatable restraint deploys rearwardly in a vehicle toward a passenger or occupant of the vehicle. The inflatable restraint, such as an airbag, may be located behind an instrument panel area, such as a dashboard. An inflatable restraint module may include an inflatable restraint canister that includes the inflatable restraint and an inflatable restraint chute. The dashboard may include an inflatable restraint door that is formed in the dashboard. Proper deployment of the inflatable restraint is necessary for the safety of the occupants of the vehicle. However, the inflatable restraint module and/or instrument panel may undergo mechanical failure or misalignment, such as a displacement of the dashboard, during the deployment of the inflatable restraint, thereby resulting in improper deployment of the inflatable restraint.  
           [0003]    Thus, a need exists for an improved inflatable restraint module that minimizes mechanical failure of the inflatable restraint module and/or instrument panel and maintains proper alignment of the inflatable restraint during deployment of the inflatable restraint.  
         SUMMARY OF THE INVENTION  
         [0004]    The inventors of the present invention have recognized these and other problems associated with conventional inflatable restraint modules. To this end, the inventors have developed a mechanism for interlocking an instrument panel to an inflatable restraint module including an attachment portion attached to a chute of the inflatable restraint module, a shaft portion extending from the attachment portion, and an engagement flange extending from the shaft portion. Upon upward displacement of the chute as a result of deployment of the inflatable restraint, the mechanism concurrently shifts with the chute, causing the engagement flange to shift from a free-floating, at-rest position to an engagement position with a structural member.  
           [0005]    In another aspect of the invention, an inflatable restraint module comprises an inflatable restraint canister including an inflatable restraint, an instrument panel including an inflatable restraint door, the instrument panel being affixed to a structural member, an inflatable restraint chute extending from the instrument panel, and a mechanism attached to the chute and including an engagement flange. Upon upward displacement of the chute as a result of deployment of the inflatable restraint, the mechanism concurrently shifts with the chute, causing the engagement flange to shift from a free-floating, at-rest position to an engagement position with the structural member. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:  
         [0007]    [0007]FIG. 1 is a side view of a mechanism for interlocking an instrument panel to an inflatable restraint module according to an embodiment of the invention;  
         [0008]    [0008]FIG. 2 is rear view of the mechanism of FIG. 1;  
         [0009]    [0009]FIG. 3 is an exploded, cutaway, rear perspective view of an inflatable restraint module and the mechanism of FIG. 1;  
         [0010]    [0010]FIG. 4A is a cutaway rear perspective view of a fully assembled inflatable restraint module including the mechanism of FIG. 1 according to one embodiment of the invention; and  
         [0011]    [0011]FIG. 4B is a cutaway front perspective view of a fully assembled inflatable restraint module including the mechanism of FIG. 1 according to another embodiment of the invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]    Referring to FIGS. 1 and 2, a mechanism  10  for interlocking an instrument panel to an inflatable restraint module is shown according to an embodiment of the invention. The mechanism  10  may be made of any desirable material, such as steel, that may be stamped or formed using any desirable process known in the art. The inventive feature and utility of the mechanism  10  is described in more detail below. Directions used in the description of the invention such as “rearward” and “vertical” are meant to establish a frame of reference in describing the invention and are not meant to restrict the or limit patentable features of the invention as described in the claims below.  
         [0013]    The mechanism  10  generally comprises an attachment portion  12  with fastener passages  14 , a shaft portion  16 , and an engagement flange  18  having any desirable widths W 1 , W 2 , and W 3 , as seen in FIG. 1, respectively, and thicknesses, T 1 , T 2 , and T 3 , as seen in FIG. 2, respectively. The engagement flange  18  may also include a least one stiffening rib  20  that may be offset or centrally located about a central axis, A, which is referenced from the mid-section of the shaft portion  16 . The stiffening rib  20  may be in the form of a groove or slot having an approximate thickness, (T 3 -T 2 ), which is approximately the thickness of the engagement flange  18  minus the thickness of the lower half of the shaft portion  16 . Alternatively, rather then being stamped in the engagement flange  18 , the stiffening rib  20  may be solid and integral with the engagement flange  18 .  
         [0014]    Referring to FIG. 1, the engagement flange  18  may also include beveled portions  22  located near the shaft portion  16  and a nose portion  24 . The beveled portions  22  may be located at any desirable location of the mechanism  10  to promote installation of the mechanism  10  about the inflatable restraint module  11 . Also, in order to promote installation of the mechanism  10  about the inflatable restraint module  11 , the engagement flange  18  may be further defined to extend from the shaft portion  16  at any desirable angle, θ, which is referenced from the central axis, A. According to the illustrated embodiment of the invention, the engagement flange  18  extends from the shaft portion  16  at an angle, θ, such that the mechanism resembles the letter “J.” The angle, θ, is referenced from the central axis, A, and an axis, P, that is substantially perpendicular to the axis, A. In the illustrated embodiment, the angle, θ, is greater than or equal to about 90°. However, it will be appreciated that the angle, θ, can be less than 90°.  
         [0015]    Referring to FIGS.  3 - 4 B, the inflatable restraint module  11  comprises the mechanism  10 , an inflatable restraint canister  26  including the inflatable restraint  28 , an inflatable restraint chute  30 , and an instrument panel or dashboard  32  including an inflatable restraint door  34  that is laser etched or otherwise formed in the dashboard  32  by using any means well known in the art. As seen in FIG. 4A, the dashboard  32  and inflatable restraint canister  26  may each be affixed to a structural member  36   a ,  36   b , respectively, which may referred to in the art as a “cross-car beam” or a “magbeam” that may be located behind a firewall (not shown). Alternatively, the dashboard  32  and inflatable restraint canister  26  can be directly or indirectly attached to the same structural member or separate structural members  36   a ,  36   b , as illustrated.  
         [0016]    The dashboard  32  may include at least a soft, aesthetically pleasing skin material  38  that is visible to the occupants of the vehicle, and a rigid substrate  40  comprising any desirable thermoplastic resin, such as, for example, Acrylnitril-Butadien-Styrol-Copolymere (ABS), Polypropylene (PP), Polycarbonate-Acrylnitril-Butadien-Styrol-Copolymere (PC/ABS), Thermoplastic Olefin (TPO), or polyvinyl chloride (PVC). The inflatable restraint chute  30  may be integral with and extend from the substrate  40 . Alternatively, the inflatable restraint chute  30  may be a separate component comprising metal that is attached to the substrate  40  with fasteners or a desirable adhesive. As illustrated in FIG. 3, fasteners  42 , such as rivets, bolts, or the like, may pass through the fastener passages  14  on the attachment portion  12  and substrate fastener passages  44  in the chute  30 . Although the substrate fastener passages  44  are disposed about the chute  30 , the attachment portion  12  may comprise an alternative structure that permits attachment of the mechanism  10  directly to the dashboard  32 .  
         [0017]    In a deployment situation, the inflatable restraint  28  inflates and deploys through the inflatable restraint door  34  towards an occupant of the vehicle. As seen in FIG. 4A, upon deployment of the inflatable restraint  28 , deployment forces, which are generally indicated by deployment geometry including a rearward vector, R, a vertical vector, V, and a thrust vector, D, occur about the inflatable restraint module  11 . The combination of the rearward vector, R, and the vertical vector, V, result in the thrust vector, D, and are each generally directed towards the occupant and the windshield, respectively. The thrust vector, D, may comprise any desirable angle, such as, for example, approximately 36 degrees, which is referenced from the rearward vector, R.  
         [0018]    Essentially, the deployment force occurring about the inflatable restraint module  11  when the inflatable restraint deploys imposes stresses on the inflatable restraint module  11 , particularly on the substrate  40  and the chute  30 , and attempts to cause upward displacement of the inflatable restraint module  11 . Generally, the vertical vector, V, comprises most of the deployment force that attempts to cause upward displacement of the chute  30  and the dashboard  32 . However, most of the deployment force associated with the vertical vector, V, is harnessed by the mechanism  10 .  
         [0019]    During displacement of the chute  30  and dashboard  32 , the mechanism  10 , which is attached to the chute  30 , concurrently shifts with the chute  30  and dashboard  32 . Accordingly, the engagement flange  18  shifts from its “at-rest position” and engages a structural member  36 , which is illustrated to be attached to the inflatable restraint canister  26 . However, the engagement flange  18  may be designed to engage another structural member that is remote from or attached to the inflatable restraint canister  26 , if desired. Engagement of the mechanism  10  against the structural member  36  ceases and restricts upward displacement of the chute  30  and dashboard  32 , thereby maintaining the relative positions of the chute  30  and the dashboard  32 .  
         [0020]    Referring to FIG. 4B, another embodiment of the inflatable restraint module  11  arrangement is illustrated. In this embodiment, the engagement flange  18  of the mechanism  10  is designed to be in an initial “at position” that will ultimately engage a fin  42  that is integral with and extends from the inflatable restraint canister  26  upon deployment of the inflatable restraint  28 . The fin  42  is hard attached to the structural member  36  with any desirable fastener such as a bolt  44 . Although the inflatable restraint canister  26  includes a fin, it is contemplated that the inflatable restraint canister  26  may include other features or designs employing other members that may be attached to the structural member  36 . The mechanism  10  operates and functions in a similar manner as described above with respect to the embodiment illustrated in FIG. 4A. Specifically, the mechanism  10 , which is attached to the chute  30 , concurrently shifts with the chute  30  and dashboard  32  and ceases and restricts upward displacement of the chute  30  and dashboard  32 , thereby maintaining the relative positions of the chute  30  and the dashboard  32 .  
         [0021]    According to the illustrated embodiments of the invention, the engagement flange  18  of the mechanism  10  may be spaced from the structural member  36  at any desirable clearance in the “at rest position,” such as, for example, a clearance approximately equal to 3 mm. Because the engagement flange  18  is spaced from the structural member  36  or fin  42 , the mechanism  10  is considered to be a “free-floating” component that reduces undesirable noise, vibration and harshness (NVH), such as rattle, during operation of the vehicle. The “free floating” aspect of the mechanism  10  also retains head impact characteristics of the inflatable restraint module  11  under occupant loading of the inflatable restraint  28  such that the dashboard  32  may bend or flex so that absorption of impact energy transmitted to the inflatable restraint  28  may be expedited about the inflatable restraint module  11 .  
         [0022]    As illustrated in FIG. 4A, the mechanism  10  may be implemented in the inflatable restraint module  11  having impact geometry including an inflatable restraint deployment angle, φ, which is referenced from a horizontal line, H, that is generally parallel from a vehicle floor or base pan (not shown). Accordingly, the mechanism  10  may be implemented in inflatable restraint modules  11  having inflatable restraint deployment angles, φ, that comprises a deployment force that urges upward displacement of the chute  30  and dashboard  32  towards the vertical vector, V. The inflatable restraint deployment angle, φ, may comprise any desirable angle, such as, for example, approximately greater than or equal to 30 degrees.  
         [0023]    Accordingly, the mechanism  10  restricts a deployment force that urges upward displacement of the chute  30  and dashboard  32  at any distance, such as, for example, a distance approximately equal to 50 mm or more, thereby impeding resulting stresses of the substrate  40  that may otherwise fracture a portion of the inflatable restraint module  11 , such as the dashboard  32 , causing improper deployment of the inflatable restraint  28 . Thus, the deployment geometry including vectors, R, V, and D, may be maintained in order to maintain proper deployment of the inflatable restraint  28 .  
         [0024]    Even further, in a head impact situation, the mechanism  10  permits the inflatable restraint module  11  to go into tension or flex upon restricting a deployment force that urges upward displacement of the chute  30  and dashboard  32 . Thus, the loading geometry including an inflatable restraint deployment angle, φ, may be maintained, thereby retaining head impact characteristics of the inflatable restraint module  11  under occupant loading of the inflatable restraint  28   
         [0025]    It should be understood that the aforementioned and other various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby.
An inflatable restraint module comprises an inflatable restraint canister including an inflatable restraint, an instrument panel, and a mechanism for interlocking the instrument panel to the inflatable restrain. The mechanism includes an attachment portion attached to a chute of the inflatable restraint module, a shaft portion extending from the attachment portion, and an engagement flange extending from the shaft portion. Upon upward displacement of the chute as a result of deployment of the inflatable restraint, the mechanism concurrently shifts with the chute, causing the engagement flange to shift from a free-floating, at-rest position to an engagement position with a structural member. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.