Abstract:
The application provides an overhead passenger airbag module for use in vehicles. The overhead passenger airbag module has a clamshell inflator housing configured to retain an airbag inflator. The inflator housing is also constructed to allow attachment of an airbag cushion to the airbag module. The overhead passenger airbag module also includes an airbag cushion having an airbag throat portion and a cushion portion. The invention also provides a method of folding the airbag cushions of the invention to aid proper deployment and help assure proper support and deceleration of a vehicle occupant during a collision event.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to methods and patterns for folding airbag cushions. More specifically, the present invention relates to methods and patterns for folding airbag cushions used in overhead-mounted vehicular airbag modules.  
         [0003]     2. Description of Related Art  
         [0004]     Safety belts are designed to protect the occupants of a vehicle during events such as automobile collisions. In low-speed collisions, the occupants are generally protected from impact with objects located inside the vehicle such as the windshield, the instrument panel, a door, the side windows, or the steering wheel by the action of the safety belt. In more severe collisions, however, even belted occupants may experience an impact with the car&#39;s interior. Airbag systems were developed to supplement conventional safety belts by deploying into the space between an occupant and an interior object or surface in the vehicle during a collision event. The airbag acts to decelerate the occupant, thus reducing the chances of injury to the occupant caused by contact with the vehicle&#39;s interior.  
         [0005]     Many typical airbag systems consist of several individual components joined to form an operational module. Such components generally include an airbag cushion, an airbag inflator, a sensor, and an electronic control unit. Airbag cushions are typically made of a thin, durable fabric that is folded to fit into a compartment of a steering wheel, dashboard, interior compartment, roof, roof rail, roof compartment, or other space in a vehicle. The airbag inflator is in fluid communication with the airbag cushion, and is configured to produce a gas to inflate the cushion when it is needed. The sensors detect sudden decelerations of the vehicle that are characteristic of an impact. The readings taken by the sensors are processed in the electronic control unit using an algorithm to determine whether a collision has occurred.  
         [0006]     Upon detection of an impact of sufficient severity, the control unit sends an electrical signal to the inflator. The inflator uses one of many technologies, including pyrotechnic compounds and pressurized gas, to produce a volume of an inflation gas. The inflation gas is channeled into the airbag, inflating it. Inflation of the airbag causes it to deploy, placing it in position to receive the impact of a vehicle occupant. After contact of the occupant with the airbag and the corresponding deceleration of the occupant, the airbag rapidly deflates. To accomplish this, the inflation gas is vented from openings in the airbag, deflating it and freeing the occupant to exit the vehicle.  
         [0007]     As experience in the manufacture and use of airbags has increased, the engineering challenges involved in their design, construction, and use have become better understood. Most airbag systems are designed to rapidly inflate and provide a cushion in proximity to a vehicle occupant. Many such cushions are configured to be placed in front of a vehicle occupant. Placement of the cushions is determined based on presumptions made of the position of a vehicle occupant during normal operation of the vehicle. Thus, a vehicle occupant enjoys optimal protection from a specific airbag when the occupant is in the presumed range of positions when the airbag deploys.  
         [0008]     In some situations, injuries have been noted to occur when the occupant is “out of position” with regard to the presumed position discussed above. Injuries similar to out of position injuries may also result from improper deployment of the airbag. Improper deployment may result in either poor placement of the cushion when contacted by a vehicle occupant or incursion of the airbag cushion into the space reserved for the vehicle occupant. Such incursion during deployment may raise the probability of injury to the vehicle occupant.  
         [0009]     Overhead airbag systems were developed as an alternative to frontally-placed airbag cushions. Such overhead cushions are advantageous in some situations since they deploy into position without exerting a force directly toward the vehicle occupant. In addition, positioning of the primary airbag in the roof of the vehicle when stored allows for greater design flexibility of the steering wheel and/or dashboard components of the vehicle.  
         [0010]     One difficulty faced in the design and installation of overhead airbags is that the trajectory of deploying overhead airbags must be carefully controlled. One reason for this is that due to their placement in a vehicle, overhead airbags may encounter sun visors or other roof-mounted accessories during deployment. Such obstacles may deflect or trap an inflating airbag cushion, thus compromising the protection provided to the vehicle occupant. As a result, there is a need in the art for overhead airbag cushion designs which facilitate proper inflation of an airbag cushion.  
         [0011]     In addition, because overhead airbag cushion modules are generally placed above vehicle occupants in vehicles, their rapid deployment downward into a vehicle cabin may place a vehicle occupant at risk of injury. This risk may be heightened when the vehicle occupant is out of the position anticipated for them in the vehicle by the vehicles&#39; engineers. More specifically, in some situations, if airbags inflate rapidly and fully as they emerge from the roof, they may impinge into space reserved for the head and/or upper body of a vehicle occupant, thus creating a potential for injury. Thus, there is a need in the art for airbag modules and airbag cushion folding methods which guide proper deployment of the airbag cushion.  
         [0012]     Accordingly, a need exists for methods of regulating the deployment trajectory of an overhead airbag cushion. More specifically, a need exists for novel inflator housings, overhead airbag designs, and folding patterns and methods for use with overhead airbag cushions and modules to improve overhead airbag performance. Such housings, airbag cushion designs, and novel folding patterns are provided herein.  
       SUMMARY OF THE INVENTION  
       [0013]     The apparatus and method of the present invention have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available inflator housings, airbag modules, airbag cushions, and airbag cushion folding patterns and methods. Thus, the present invention provides novel inflator housings, airbag modules, airbag cushions, and airbag cushion folding patterns and methods.  
         [0014]     In accordance with the invention as embodied and broadly described herein, a novel airbag module, an airbag inflator housing, an airbag cushion, and a related airbag cushion folding method are provided primarily for use in overhead airbag applications. The invention first provides an airbag module for protecting a vehicle occupant. In some embodiments, the airbag module of the invention may be configured to be used in the passenger side of a vehicle. The airbag module generally includes an airbag inflator, an airbag cushion, and a one-piece clamshell inflator housing. The airbag cushion of the invention generally includes a cushion throat and a cushion portion. The cushion portion may further include a center face, an inboard face, and an outboard face. Regions of the cushion described by the term “face” may be distinct panels of the airbag cushion, or alternatively, may simply be regions of the airbag oriented or positioned in a particular fashion.  
         [0015]     The one-piece clamshell inflator housing of the invention includes an inflator sleeve for closeably receiving an airbag inflator and a diffuser sleeve for diffusing an inflation fluid produced by the airbag inflator as it enters an airbag cushion. More specifically, the inflator sleeve is shaped and constructed to close about an airbag inflator and to provide a diffuser for the final airbag module. The inflator housing may include fasteners, straps, welds, or other mechanical joints known in the art for maintaining the clamshell inflator housing in a closed position. The diffuser sleeve portion of the inflator housing may include elements on both sides of the clamshell housing, and thus may be configured for use by closing the clamshell inflator housing.  
         [0016]     The inflator housing may additionally include cushion attachments for attaching an airbag cushion to the inflator housing. In some specific embodiments of the housing of the invention, the cushion attachments may be attachment pegs. In others, attachment means such as bolts, clamps, or adhesives may be used. In some embodiments of the invention, the airbag cushion may be attached directly about the inflator housing. This may result in the inflator housing being at least partially enclosed by the airbag cushion. The inflator housing and the cushion attachments may further be configured to allow attachment of the inflator or the completed airbag module to a vehicle.  
         [0017]     The invention further provides an airbag cushion having a cushion throat used for transmission of inflation gas from the inflator into the cushion. The cushion throat of the airbag cushion includes a loop diffuser for diffusing a flow of inflation fluid produced by an airbag inflator as it enters the airbag cushion. This loop diffuser of the cushion throat may take the form of a secondary internal sleeve of the cushion throat having a closed end and at least one diffuser orifice for diffusing the inflation gas produced by an airbag inflator as it is transmitted into the airbag cushion. The secondary internal sleeve may be constructed of several individual panels or of a single panel joined to itself to form a tubular structure with a closed end and at least one diffuser orifice. The diffuser orifice may simply be an orifice of a variety of shapes, such as circular and oval, but which permits the passage of inflation fluid from the loop diffuser to the cushion portion of the airbag cushion.  
         [0018]     In one embodiment, the internal sleeve of the loop diffuser has a windshield-facing panel and an occupant-facing panel, the panels being attached to form a closed sleeve having at least one diffuser orifice. The diffuser orifice may be positioned on either or both of the panels. The airbag cushion of the invention having the loop diffuser may be an overhead airbag cushion, or may be used elsewhere in a vehicle. More specifically, the airbag of the invention having a loop diffuser may be used in frontal airbags such as those installed in steering wheels/columns and dashboards, side-curtain airbags, thorax/pelvic airbags, and other airbags mounted in the roof, dashboard, or seats of a vehicle.  
         [0019]     The airbag cushion of the invention may additionally be constructed to allow attachment of the cushion to an airbag inflator housing of the invention having cushion attachments. In some embodiments, this includes constructing the airbag cushion to include elements which securely attach to the cushion attachments of the inflator housing. Such elements may be simple, such as an eyelet for passing over an attachment peg. Alternatively, these attachment elements may utilize multiple attachment pegs or peg arrangements to aid in proper attachment and to provide a secure mount. Other more complex attachment means, including bolts, clamps, adhesives, etc., are within the knowledge of one of skill in the art, and are thus included within the scope of this invention.  
         [0020]     The invention further provides a folding method for use with the airbag cushions of the invention. In some embodiments, the method includes the steps of providing an airbag cushion having an inboard face, an outboard face, and an inflation orifice; flattening the airbag cushion; tucking the inboard and outboard faces of the airbag cushion inwardly to produce at least one longitudinal pleat and a first folded end and a second folded end; drawing first and second folded ends of the airbag cushion produced in the previous steps toward each other to position them directly opposite the inflation orifice; rolling the first folded end of the airbag cushion toward the inflation orifice to produce a first roll fold; and rolling the second folded end of the airbag cushion toward the inflation orifice to produce a second roll fold, wherein the second roll fold encompasses the first roll fold. In some of the folding methods of the invention, the step of tucking the inboard and outboard faces of the airbag cushion inwardly to produce at least one longitudinal pleat is repeated to produce a plurality of longitudinal pleats. In specific methods, 3 longitudinal pleats are produced. Further, in some methods, the step of rolling the first folded end of the airbag cushion toward the inflation orifice comprises rolling the first folded end against either the windshield or occupant face of the airbag cushion.  
         [0021]     In another folding method of the invention, a folding method for use with an overhead airbag module of the invention is provided. This method may include the steps of providing an airbag cushion having a center face, an inboard face, an outboard face, and a cushion throat with an inflation orifice; providing an inflator housing for receiving and retaining an airbag inflator, the inflator housing including at least one cushion attachment; attaching the cushion throat of the airbag cushion to the inflator housing; flattening the airbag cushion; tucking the inboard and outboard faces of the airbag cushion inwardly to produce at least one longitudinal pleat and a first folded end and a second folded end; drawing the first and second folded ends of the airbag cushion toward each other to position them directly opposite the airbag inflator; rolling a folded end of the airbag cushion toward the airbag inflator to produce a roll fold; and rolling the remaining folded end of the airbag cushion toward the airbag inflator to produce a roll fold, wherein the roll fold produced last encompasses the roll fold produced first.  
         [0022]     In such folding methods, the step of attaching the cushion throat of the airbag cushion to the inflator housing may include at least partially encompassing the inflator housing with the cushion throat and attaching the cushion throat to the cushion attachment of the inflator housing. Further, as above, the step of tucking the inboard and outboard faces of the airbag cushion inwardly to produce at least one longitudinal pleat is repeated to produce a plurality of longitudinal pleats, in some methods producing 3 longitudinal pleats. In addition, the steps of rolling the ends of the airbag cushion toward the inflation orifice may comprise rolling them toward or away from the attachment flanges of the airbag cushion.  
         [0023]     The patterns and methods of the invention may be specifically useful in overhead airbag applications. Alternatively, however, the patterns and methods of the invention may be useful in other airbag applications including, but not limited to side curtain airbags, frontally-mounted dashboard or steering wheel-mounted airbags, thorax airbags, and vehicle pillar airbags.  
         [0024]     These and other features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     In order that the manner in which the above-recited and other features and advantages of the invention are obtained will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:  
         [0026]      FIG. 1A  is an isolated perspective view of a clamshell airbag inflator housing of the invention;  
         [0027]      FIG. 1B  is an end view of the inflator housing of  FIG. 1A  taken at line  1 B- 1 B of  FIG. 1A ;  
         [0028]      FIG. 1C  illustrates the end view of the inflator housing of  FIG. 1B  in a closed configuration;  
         [0029]      FIG. 1D  is a longitudinal cross-sectional view of the inflator housing of  FIG. 1A  taken at line  1 D- 1 D of  FIG. 1A ;  
         [0030]      FIG. 2  shows an isolated perspective view of the inflator housing of the invention of  FIGS. 1A-1D  shown attached about an airbag inflator;  
         [0031]      FIG. 3  shows a partial perspective view of a vehicle including an airbag module of the invention deployed and shown in a partial cross-sectional view to reveal the loop diffuser of the airbag cushion of the invention;  
         [0032]      FIG. 4A  shows a perspective view of an inflator housing of the invention aligned for attachment to an airbag cushion of the invention prior to cushion attachment, folding, and assembly to form an airbag module of the invention;  
         [0033]      FIG. 4B  illustrates initial steps of a method of attaching an airbag of the invention to an airbag housing of the invention and an initial step of a method of folding the airbag cushion to prepare an airbag module of the invention;  
         [0034]      FIG. 4C  shows a longitudinal pleat-folding step of the airbag cushion folding method of the invention;  
         [0035]      FIG. 4D  shows a cross-sectional view of a portion of the longitudinally pleat-folded airbag cushion of  FIG. 4C  taken at line  4 D- 4 D;  
         [0036]      FIG. 4E  shows a cross-sectional view of a the airbag cushion assembly of  FIG. 4C  taken at line  4 E- 4 E prior to which the cushion ends had been placed together and drawn away from the inflator housing;  
         [0037]      FIG. 4F  shows a cross-sectional view of the airbag cushion of  FIG. 4E  having undergone an additional folding step;  
         [0038]      FIG. 4G  shows a cross-sectional view of the airbag cushion of  FIG. 4F  having undergone a first roll-folding step; and  
         [0039]      FIG. 4H  shows a completed airbag module according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0040]     The presently preferred embodiments of the present invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the present invention, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the apparatus, system, and method of the present invention, as represented in  FIGS. 1 through 4 H, is not intended to limit the scope of the invention, as claimed, but is merely representative of presently preferred embodiments of the invention.  
         [0041]     The production of airbag systems capable of being stowed and deployed from the roof of a vehicle provides additional flexibility to vehicle designers and gives safety engineers another option for protecting vehicle occupants in specific vehicle designs. Although innovative and effective, overhead airbag systems also face difficulties in their design and implementation. More specifically, such systems often face constraints in the space available for them in a vehicle, as well as strict requirements for the deployment of the airbag cushion. Thus, the invention provides a novel airbag module having a novel inflator housing, airbag cushion, and airbag folding method suited for use in an overhead airbag application.  
         [0042]     Referring first to  FIG. 1A , an isolated perspective view of a clamshell airbag inflator housing  10  of the invention is shown. The inflator housing  10  includes an inflator sheath portion  20  and a diffuser sleeve  40 . The inflator housing  10  is configured in size and shape to receive an airbag inflator and to be mounted to a vehicle. The clamshell inflator housing  10  may subsequently be fastened about the airbag inflator to securely hold the inflator in place. The inflator housing  10  additionally includes features which may be used in mounting an airbag cushion (not shown) to the housing  10  as part of an airbag module. In  FIG. 1A , these features may include peg openings  32  in the inflator sheath  20  portion, and airbag mounting pegs  34  extending through the openings  32  in a transverse direction  50 . The inflator housing  10  still further includes a diffuser sleeve  40  for diffusing a flow of inflation gas (not shown) as it exits an inflator and is directed into an airbag cushion.  
         [0043]     The inflator sheath portion  20  is a generally tubular structure with a substantially tubular sheath wall  22  extending from a first end  12  of the inflator housing  10  to a second end  14  of the inflator housing  10  in a longitudinal direction  52 . As briefly mentioned above, the inflator sheath  20  is produced to receive an airbag inflator. More specifically, the inflator sheath portion  20 , or the inflator housing  10  as a whole, may be constructed of a material having sufficient flexibility and/or resilience to be opened to receive an inflator, and then later to be closed about the inflator to retain it in place.  
         [0044]     In some embodiments, the inflator housing  10  may include pairs of closure flanges  28   a,    28   b  which are placed on opposing walls  42   a,    42   b  of the diffuser sleeve  40  to abut each other when the housing  10  is closed. Fastener openings  30  may be placed in the closure flanges  28   a,    28   b  to keep the inflator sleeve closed. Alternatively, means such as welding, adhesives, clamps, or a large variety of fastening devices may be used to fasten the closure flanges  28   a,    28   b  together. In some embodiments of the inflator housing  10  of the invention, closure flanges  28   a,    28   b  may be crimped, folded, or otherwise mechanically linked to close the housing  10 . In still other housings of the invention, closure flanges  28   a,    28   b  are omitted, and the inflator sheath  20  and diffuser sleeve  40  are attached to each other directly. This may be accomplished using welding or other attachment measures known in the art. Alternatively, external attachment clamps or other means may be used.  
         [0045]     The inflator sheath  20  is also shown to include peg openings  32  through which airbag cushion mounting pegs  34  extend outwardly from the inflator sheath  20 . As shown in  FIG. 1A , the openings  32  and the pegs  34  may be placed in an asymmetrical manner to assure proper orientation of an airbag cushion during assembly an airbag module. Such pegs  34  may attach to, or pass through portions of an airbag cushion (not shown) to attach the cushion to the inflator housing  10 . In addition, pegs  34  may be used to attach the inflator housing  10  to a vehicle as part of a completed airbag module. Alternate airbag cushion attachment methods and mechanisms known in the art may be used, including clamps or other similar apparatus.  
         [0046]     The diffuser sleeve  40  of the inflator housing  10  is also illustrated in  FIG. 1A . The diffuser sleeve  40  projects outwardly from the inflator sheath  20  substantially in a transverse direction  50 , which in  FIGS. 1A through 1D  is substantially perpendicular to the inflator sheath  20 . Other angles may be used in varying circumstances to impart a desired direction to a flow of inflation gas produced by an inflator placed in the inflator housing  10 . The diffuser sleeve  40  of  FIGS. 1A-1D  is shown to be slightly-funnel-shaped, and having a slightly flattened oval shape. One of skill in the art could vary the precise shape of the diffuser sleeve within the scope of the invention.  
         [0047]     As briefly described above, the diffuser sleeve  40  is here shown to be formed from first and second sleeve walls  42   a,    42   b  present on opposing sides of the substantially tubular wall  22  of the inflator sheath  20 . When the inflator sheath  20  is closed, the first and second sleeve walls  42   a,    42   b  are brought into contact, forming the funnel-shaped diffuser sleeve  40 . As discussed above, this structure may be stabilized in a large variety of ways, including attaching closure flanges such as  28   a,    28   b  together, or by directly attaching closure flanges  28   a,    28   b  or the individual sleeve walls  42   a,    42   b.  When an inflator has been installed in the inflator housing  10  of the invention, the outlet port protrudes from the inflator sheath  20  into the diffuser sleeve  40 . When the inflator is initiated, the inflation gas produced is emitted into the diffuser sleeve  40 , which directs it away from the inflator into an airbag cushion attached to the inflator housing  10 .  
         [0048]     Referring next to  FIG. 1B , an end view of the inflator housing  10  of  FIG. 1A  is shown taken from line  1 B- 1 B of  FIG. 1A . As above, the inflator housing  10  includes an inflator sheath  20  and a diffuser sleeve  40 . The inflator sheath  20  includes a sheath wall  22 , here shown open to receive an airbag inflator. The diffuser sleeve  40  includes first and second sleeve walls  42   a,    42   b.  The inflator sheath  20  is further shown to include peg openings  32 , here in the form of slightly recessed wells which accommodate an airbag mounting peg  34 , here shown to be a bolt with threads.  
         [0049]      FIG. 1C  shows the same end view of the inflator housing  10  of  FIG. 1B  taken from line  1 B- 1 B of  FIG. 1A , with the modification that the clamshell housing  10  has been closed by uniting diffuser sleeve walls  42   a,    42   b  to form the completed diffuser sleeve  40 . In this configuration, the inflator sheath  20  of the airbag housing  10  will retain an airbag inflator, and the diffuser sleeve  40  will diffuse and direct inflation gas produced by the airbag inflator.  
         [0050]      FIG. 1D  is a longitudinal cross-sectional view of the inflator housing of  FIG. 1A  taken at line  1 D- 1 D of  FIG. 1A . As in the previously-discussed Figures, the inflator housing  10  includes an inflator sheath  20  and a diffuser sleeve  40 . The inflator sheath  20  is a tubular structure for accommodating an airbag inflator which further accommodates airbag cushion mounting pegs  34  which are passed through recessed peg openings  32 . The diffuser sleeve  40  projects outwardly in a transverse direction  50  from the inflator sheath  20 .  
         [0051]      FIG. 2  shows a perspective view of the inflator housing  10  of  FIGS. 1A-1D  attached about an airbag inflator  60 . As discussed above, the inflator housing  10  is shown to have received and been closed in a lateral direction  54  about an airbag inflator  60 . Airbag cushion attachment pegs  34  extend from the housing  10 . In this figure, the pegs  34  are shown to be simple pegs, not having screw threads, while in  FIGS. 1A-1D , the pegs  34  are shown as bolts. One of skill in the art could vary the configuration of the pegs  34  to provide a secure attachment for an airbag cushion to the housing  10 .  
         [0052]     The outlet port  62  of the inflator  60  extends outwardly from the main body of the inflator  60  into the diffuser sleeve  40  of the inflator housing  10 . The outlet port  62  is shown to include outlets  64  which permit an inflation gas to exit the inflator  60 . In  FIG. 2 , the inflator housing  10  is shown to be held closed by fasteners  29  passing through the paired closure flanges  28   a,    28   b.  In  FIG. 2 , a single fastener opening  30  is used, but one of skill in the art could vary the design to use multiple fastener openings  30  within the scope of the invention. In this manner, the sleeve walls  42   a,    42   b  of the diffuser sleeve  40  are held in place, forming the shape of diffuser sleeve  40 .  
         [0053]     The invention of the instant application further provides an airbag cushion for use with the inflator housing of the invention. The airbag cushion may be configured for use as an overhead airbag positioned such that the cushion deploys from substantially above a vehicle occupant forward in a longitudinal direction  52 , and downward in a transverse direction  50 . The airbag cushions of the invention are configured to be attached to the inflator housings of the invention.  FIG. 3  shows a partial perspective view of a vehicle  130  in which an airbag module  120  of the invention has been installed and deployed.  
         [0054]     Referring next to  FIG. 3 , the airbag cushion  70  of the overhead airbag module  120  is depicted in a partial cross-sectional view, thus revealing a loop diffuser  100  of the airbag cushion  70  positioned internally to the cushion  70  to direct and diffuse a flow of inflation fluid produced by an airbag inflator  60 . In  FIG. 3 , the overhead airbag module  120  is shown positioned in the passenger side of the vehicle  130 . The invention may additionally be suited for use in a driver side of the vehicle  130  by one of ordinary skill in the art. In the vehicle  130  shown in  FIG. 3 , a vehicle occupant  152  is presented secured to a seat  142  by a seat belt  144 , and surrounded by a side door  150  and window  148 , a dashboard  146  and a windshield  132 . In  FIG. 3 , the airbag module  120  is shown placed in the passenger side of the vehicle  130 . As illustrated, the airbag module  120  is mounted in a roof  138  of a vehicle and covered by a headliner  140 . A sun visor  134 , held to the vehicle  130  by a visor mount  136  is located in front of the module  120  in a longitudinal direction  52 .  
         [0055]     The airbag module  120  is composed of an inflator housing  10 , an airbag inflator  60 , and an airbag cushion  70 . The airbag cushion  70  is composed primarily of a cushion portion  88 , a cushion throat  90 , and a loop diffuser  100 . The cushion portion  88  is generally composed of a looping center panel  76 , an outboard panel  84 , and an inboard panel  80  similar to the outboard panel  84  (shown removed for clarity). These panels  76 ,  80 ,  84  unite to form a spacious cushion  88  which may be sized to properly decelerate a vehicle occupant  152  in a specific space. The cushion portion  88  of the airbag cushion  70  is then attached to a cushion throat  90  which attaches the cushion  70  to the airbag inflator housing  10  and inflator  60  described above. In the embodiment of the cushion  70  shown in  FIG. 3 , the cushion throat  90  includes a top throat panel  92  and a bottom throat panel  94 . As seen in the detail view of  FIG. 3 , the top throat panel  92  and the bottom throat panel  94  include attachment flaps  96   a,    96 b and loops  98 . The loops  98  are passed over the attachment pegs  34  of the inflator housing  10 , securing the airbag cushion  70  to the inflator housing  10 .  
         [0056]     The loop diffuser  100  may be constructed as a second layer within the cushion throat portion  90  of the cushion  70 . In  FIG. 3 , the loop diffuser  100  includes a top diffuser panel  102 , a bottom diffuser panel  108 , and at least one diffuser outlet  114 . The loop diffuser  100  rapidly inflates, and then serves to channel and direct a flow of inflation gas from the inflator  60  into the cushion portion  88  of the cushion  70 . In some embodiments, as shown in  FIG. 3 , the inflation gas flows through at least one diffuser outlet  114 . The number and positioning of the diffuser outlets  114  may be varied within the scope of the invention.  
         [0057]     In one example of this, the loop diffuser  100  shown in  FIG. 3  includes multiple diffuser outlets  114  to permit rapid transmission of inflation gas through the diffuser  100  into the cushion portion  88 . Further, the diffuser outlets  114  of the airbag cushion  70  of  FIG. 3  are shown clustered on the bottom diffuser panel  108 . This directs the inflation gas downward into the cushion portion  88  of the airbag cushion  70 . In other embodiments, it may be desirable to at least in part direct inflation gas in an upward fashion, in which case at least one diffuser outlet  114  could be placed in the top diffuser panel  102 .  
         [0058]     Referring next to  FIGS. 4A through 4H , a method of assembling an airbag module including the inflator housing  10 , airbag cushion  70 , and a folding method of the invention are shown.  FIG. 4A  shows a first step of this folding and assembly method in which the inflator housing  10 , enclosing an airbag inflator  60 , is brought into alignment with the airbag cushion  70 . More specifically, the inflator  60  is first placed into the housing  10 , which is next closed securely about the inflator  60 . Following this, the diffuser sleeve  40  of the inflator housing  10  may be inserted into the cushion throat  90  of the airbag cushion  70 . The attachment flaps  96   a,    96   b  of the top and bottom throat panels  92 ,  94  of the cushion throat  90  are then wrapped around the inflator housing  10 . Loops  98  of the attachment flaps  96   a,    96   b  are then placed over the pegs  34  of the inflator housing  10  to secure the airbag cushion  70  to the housing  10 .  
         [0059]     Referring next to  FIG. 4B , a next step in the folding method of the invention is shown. More specifically, the airbag cushion  70  is substantially flattened, with the center panel  76  of the cushion  70  being substantially flattened against itself. In  FIG. 4B , the inflator housing  10  is generally centered against the flattened cushion  70 . In alternate embodiments of the folding method of the invention, the inflator housing  10  may be placed off-of-center to influence the deployment characteristics of the airbag cushion  70 .  
         [0060]     In a next step of the method illustrated in  FIGS. 4C and 4D , the inboard and outboard panels  80 ,  84  of the airbag cushion  70  are tucked inwardly at least once to produce lateral tuck folds  118 . In the folding method illustrated in  FIGS. 4C and 4D , two lateral tuck folds  118  are produced. As shown in  FIG. 4C , this narrows the airbag cushion  70  to approximately the width of the inflator  60 . In addition, this step forms folded ends  116   a,    116   b  of the airbag cushion  70 .  FIG. 4D  is a view of the airbag cushion of  FIG. 4C  taken at line  4 D- 4 D of  FIG. 4C . The number and size of the lateral tuck folds  118  illustrated in  FIG. 4D  may be widely varied within the scope of the invention to accommodate airbags of varying sizes, desired module sizes, and other related issues.  
         [0061]     Referring next to  FIG. 4E , a next step of the method of the invention is shown in which the inflator housing  10  and inflator are drawn to one side, uniting first and second folded ends  116   a,    116   b.  This step is illustrated in  FIG. 4E  with a side plan view of the airbag cushion  70  and inflator housing  10  taken from line  4 E- 4 E of  FIG. 4C . This step may be performed by drawing the folded ends  116   a,    116   b  together and drawing the airbag inflator  60  and inflator housing  10  away from the folded ends  116   a,    116   b.  This prepares the airbag cushion  70  for final folding to condense the body of the airbag cushion  70  and compact it such that it is small enough to be installed in a vehicle for potential use. The detail view shared between  FIGS. 4E and 4F  shows the projection of the attachment peg  34  from the inflator housing  10 . The attachment flaps  96   a,    96   b  extend and are attached about the pegs  34  to anchor the cushion  70  to the housing  10 .  
         [0062]      FIG. 4F  shows the side plan view of the airbag cushion  70  and inflator housing  10  of  FIG. 4E , taken from line  4 E- 4 E of  FIG. 4C , having undergone an additional folding step. In this additional folding step, one of the cushion ends  116   a,    116   b  is rolled toward the inflator housing. In the embodiment of the folding method of the invention illustrated in  FIG. 4F , the second folded end  116   b  is rolled toward the inflator  60  and inflator housing  10 . This rolling step produces a roll fold  124   b.  In  FIG. 4F , this roll fold  124   b  is oriented toward the attachment flaps  96   a,    96   b  of the cushion throat  90  of the airbag cushion  70 . In alternative embodiments of the folding method of the invention, the roll fold  124   b  could be produced such that it is oriented away from the attachment flaps  96   a,    96   b.    
         [0063]     Referring finally to  FIG. 4G , a final step in this embodiment of the folding method is shown. More specifically,  FIG. 4G  shows the side plan view of the airbag cushion  70  and inflator housing  10  of  FIG. 4E , taken from line  4 E- 4 E of  FIG. 4C , having undergone yet another folding step. In this added folding step, the first folded end  116   a  is also rolled toward the inflator housing  10 , producing a roll fold  124   a.  In this step, the first folded end  116   a  is first rolled into a roll fold  124   a,  and is then rolled about the roll fold  124   b.  In the embodiment shown in  FIG. 4G , the roll fold is produced with an orientation away from the attachment flaps  96   a,    96   b.  In other embodiments of the invention, the roll fold  124   a  may be produced with an orientation toward the attachment flaps  96   a,    96   b.  This step thus completes the primary folding steps of the folding method of the invention and substantially completes an airbag module  120 .  
         [0064]     In some embodiments of the invention, the airbag module  120  may additionally include an airbag module cover  122 . The airbag module cover  122  may take several forms, including a pouch-like configuration, or a configuration in which the airbag cushion  70  is simply wrapped in cloth.  
         [0065]     The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.