Abstract:
Folding methods and patterns for folding an inflatable curtain airbag cushion for use in vehicles are provided. The folding patterns and methods of the invention assist in preventing failure of inflatable curtain airbag cushions by reducing the stress placed on specific regions of the longitudinal fill chambers of the cushions. These methods result in proper airbag deployment with reduced rates of cushion failure, thus providing reliable protection to vehicle occupants.

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 to mitigate stresses observed in cushions folded using currently-known methods.  
         [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 occurred 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]     Inflatable curtain airbag systems were developed to supplement frontally-placed airbag cushions. Such laterally-deploying cushions are advantageous in some situations since they deploy into position alongside an occupant without exerting a force directly toward the vehicle occupant.  
         [0010]     One difficulty faced in the design and installation of inflatable curtain airbag cushions is a tendency for the fabric of such cushions to fail during deployment, thus compromising the protection available to a vehicle occupant. Studies have revealed that this failure is often due to high stress placed on specific portions of the cushion. Some currently-used airbag curtains are folded for storage using a “roll plus one fold”—a roll-fold followed by a single unidirectional pleat fold. In some cases, it has been discovered that the centerline of the pleat fold is often specifically subjected to high stress during deployment.  
         [0011]     Accordingly, a need exists for methods of reducing the stress placed on a deploying inflatable curtain airbag cushion. More specifically, a need exists for novel folding patterns and methods for use with inflatable curtain airbag cushions to help prevent cushion failure. Such novel folding patterns are provided herein.  
       SUMMARY OF THE INVENTION  
       [0012]     The method of the present invention has 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 airbag folding patterns and methods. Thus, the present invention provides novel methods and patterns for folding automobile airbag cushions such as inflatable curtain airbag cushions.  
         [0013]     In accordance with the invention as embodied and broadly described herein in the preferred embodiment, methods and patterns for folding vehicular airbag cushions are provided. The folding methods of the invention may be especially well-suited to use with airbag cushions such as airbag curtains. In one embodiment, the method of the invention comprises the steps of providing an airbag cushion having a longitudinal fill chamber in fluid communication with a contact chamber, the chambers each having an inboard face and an outboard face, flattening the inboard face of the airbag cushion against the outboard face of the airbag cushion, compression-folding the contact chamber portion of the airbag cushion, and pleat-folding the inboard face and the outboard face of the longitudinal fill chamber portion of the airbag cushion.  
         [0014]     In the methods of the invention, the step of pleat-folding the inboard face and the outboard face of the longitudinal fill chamber of the airbag cushion involves producing a single outwardly-facing pleat in the inboard face of the airbag cushion and a single outwardly-facing pleat in the outboard face of the airbag cushion. Thus folded, interior portions of the inboard face and the outboard face of the longitudinal fill chamber are placed into contact with themselves.  
         [0015]     In some embodiments of the invention, the step of pleat-folding the inboard face and the outboard face of the longitudinal fill chamber of the airbag cushion may be followed by a step of wrapping the pleat of the inboard face and the pleat of the outboard face about the compression-folded contact chamber portion of the airbag cushion. This produces a folded configuration referred to herein as the “inverted-U” configuration.  
         [0016]     In alternate embodiments of the folding methods of the invention, the step of pleat-folding the inboard face and the outboard face of the longitudinal fill chamber of the airbag cushion may be followed by a step of folding the pleat of the inboard face and the pleat of the outboard face away from the previously-compression-folded contact chamber of the airbag cushion. Following this step, an added step of placing the compression-folded contact chamber portion of the airbag cushion against the inboard pleat of the airbag cushion may be conducted. Alternately, this final step may entail placing the compression-folded contact chamber portion of the airbag cushion against the outboard pleat of the airbag cushion. These methods produce a fold referred to herein as the “W-fold.” 
         [0017]     In the methods of the invention, the step of compression-folding the contact chamber portion of the inflatable curtain airbag cushion may include roll-folding the airbag cushion. In some methods of the invention, roll-folding the airbag cushion comprises rolling the contact chamber portion of the airbag cushion toward the inboard face of the airbag cushion. In others, roll-folding the airbag cushion comprises rolling the contact chamber portion of the airbag cushion toward the outboard face of the airbag cushion. In alternate embodiments of the invention, the step of compression-folding the contact chamber portion of the inflatable curtain airbag cushion may include pleat-folding. In still others, the step of compression-folding the contact chamber portion of the inflatable curtain airbag cushion may include random folding generated by crumpling or vacuum-packing the cushion.  
         [0018]     In some specific methods of the invention, methods of the invention are tailored for use with curtain airbags. Such methods of folding inflatable curtain airbag cushions may include the steps of providing an inflatable curtain airbag cushion having a longitudinal fill chamber in fluid communication with a contact chamber, the chambers each having an inboard face and an outboard face; flattening the inboard face of the airbag cushion against the outboard face of the airbag cushion; compression-folding the contact chamber portion of the airbag cushion; and pleat-folding the inboard face and the outboard face of the longitudinal fill chamber portion of the airbag cushion. In such methods, the inflatable curtain airbag provided may additionally include an attachment edge for mounting the cushion to a vehicle, and a distal edge at an end of the curtain opposite the attachment edge.  
         [0019]     As above, in the methods of the invention for use with inflatable curtain airbags, the step of pleat-folding the inboard face and the outboard face of the longitudinal fill chamber portion of the airbag cushion may involve producing a single outward-facing pleat in the inboard face of the airbag cushion and a single outward-facing pleat in the outboard face of the longitudinal fill chamber portion of the airbag cushion. Thus folded, interior portions of the inboard face and the outboard face of the longitudinal fill chamber are placed into contact with themselves.  
         [0020]     In some embodiments of the invention, the step of pleat-folding the inboard face and the outboard face of the longitudinal fill chamber of the airbag cushion may be followed by a step of wrapping the pleat of the inboard face and the pleat of the outboard face about the compression-folded contact chamber portion of the airbag cushion. This produces a folded configuration referred to herein as the “inverted-U” configuration.  
         [0021]     In alternate embodiments of the folding methods of the invention, the step of pleat-folding the inboard face and the outboard face of the longitudinal fill chamber of the airbag cushion may be followed by a step of folding the pleat of the inboard face and the pleat of the outboard face away from the previously-compression-folded contact chamber of the airbag cushion. Following this step, an added step of placing the compression-folded contact chamber portion of the airbag cushion against the inboard pleat of the airbag cushion may be conducted. Alternately, this final step may entail placing the compression-folded contact chamber portion of the airbag cushion against the outboard pleat of the airbag cushion. These methods produce a fold referred to herein as the “W-fold.” 
         [0022]     In the methods of the invention, the step of compression-folding the contact chamber portion of the inflatable curtain airbag cushion may include roll-folding the airbag cushion. In some methods of the invention, roll-folding the airbag cushion comprises rolling the contact chamber portion of the airbag cushion toward the inboard face of the airbag cushion. In others, roll-folding the airbag cushion comprises rolling the contact chamber portion of the airbag cushion toward the outboard face of the airbag cushion. In alternate embodiments of the invention, the step of compression-folding the contact chamber portion of the inflatable curtain airbag cushion may include pleat-folding. In still others, the step of compression-folding the contact chamber portion of the inflatable curtain airbag cushion may include random folding generated by crumpling or vacuum-packing the cushion.  
         [0023]     The patterns and methods of the invention may be specifically useful in inflatable curtain airbag applications. Alternatively, however, the patterns and methods of the invention may be useful in other airbag applications including, but not limited to frontally-deployed 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. 1  is a partial perspective view of a vehicle showing an inflatable curtain airbag cushion partially deployed and inflated;  
         [0027]      FIG. 2A  shows an initial flattening step of a method of folding an airbag according to the invention;  
         [0028]      FIG. 2B  shows the configuration produced by the partial completion of a step of compression-folding a contact chamber portion of the airbag cushion step according to methods of folding an airbag according to the invention;  
         [0029]      FIG. 2C  shows the configuration produced by the compression-folding step and the step of pleat-folding the inboard and outboard faces of the longitudinal fill chamber of the airbag cushion of the method of folding an airbag of the invention;  
         [0030]      FIG. 2D  shows the configuration produced by a step of tucking the compression-folded contact cushion into the pleat-folded longitudinal fill chamber of a method of folding an airbag according to the invention;  
         [0031]      FIG. 2E  shows an alternate final folded configuration produced in which the contact chamber is compression-folded by rolling the contact chamber toward the outboard face of the airbag cushion in a method of folding an airbag according to the invention;  
         [0032]      FIG. 2F  shows an alternate final folded configuration produced in which the contact chamber is compression-folded by accordion-folding the contact chamber toward the outboard face of the airbag cushion in a method of folding an airbag according to the invention;  
         [0033]      FIG. 3A  shows an initial flattening step of an alternate method of folding an airbag according to the invention;  
         [0034]      FIG. 3B  shows the configuration produced by the partial completion of a step of compression-folding the contact chamber portion of the airbag cushion step according to an alternate method of folding an airbag according to the invention;  
         [0035]      FIG. 3C  shows the configuration produced by the compression-folding step and the step of pleat-folding the inboard and outboard faces of the longitudinal fill chamber of the airbag cushion according to an alternate method of folding an airbag of the invention;  
         [0036]      FIG. 3D  shows the configuration produced by a step of placing the compression-folded contact cushion against the inboard face of the pleat-folded longitudinal fill chamber of the airbag cushion of an alternate method of folding an airbag according to the invention;  
         [0037]      FIG. 3E  shows an alternate final folded configuration produced in which the contact chamber is compression-folded by rolling the contact chamber toward the outboard face of the airbag cushion in an alternate method of folding an airbag according to the invention; and  
         [0038]      FIG. 3F  shows an alternate final folded configuration produced in which the contact chamber is compression-folded by accordion-folding the contact chamber toward the outboard face of the airbag cushion in an alternate method of folding an airbag according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0039]     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 steps 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 methods of the present invention, as represented in  FIGS. 1 through 3 F, is not intended to limit the scope of the invention, as claimed, but is merely representative of presently preferred embodiments of the invention.  
         [0040]     Inflatable curtain airbag cushions have grown in popularity and use in the past several years. One difficulty faced in the design and installation of inflatable curtain airbag cushions is a tendency for the fabric of such cushions to fail during deployment, thus compromising the protection available to a vehicle occupant. Studies conducted by the applicants revealed that this failure is often due to high stress placed on specific portions of the cushion. Some currently-used airbag curtains are folded for storage using a “roll plus one fold”—a roll-fold followed by a single unidirectional pleat fold. It has been discovered that the centerline of the pleat fold is often specifically subjected to high stress during deployment.  
         [0041]     Countermeasures proposed to combat the failure of inflatable curtain airbag cushions have included reinforcement of the centerline region and the longitudinal fill region in general. Such reinforcements raise the costs of airbag cushions and the complexity of their manufacture.  
         [0042]     The airbag folding patterns and methods of the invention are provided to reduce and/or dissipate the stress placed on regions of the longitudinal fill region of inflatable curtain airbag cushions during deployment. Referring first to  FIG. 1 , a partial perspective view of a vehicle  12  is shown in which an inflatable curtain airbag cushion  10  has been mounted and partially deployed and inflated. The vehicle  12  is shown to include a dashboard  14  placed forward of a seat  24  for supporting a vehicle occupant (not shown). A dashboard  14  and steering wheel  18  are positioned forward of the seat  24  in a longitudinal direction  36 . A side pillar  16 , door  20 , and window  22  are positioned in a lateral direction  34  from the seat  24 . During operation of the vehicle  12 , a vehicle occupant would be secured to the seat  24  by a seatbelt  26 .  
         [0043]     The inflatable curtain  10  is suspended from the roof  30  of the vehicle  12 . The airbag curtain  10  includes a longitudinal fill chamber portion  40  and a contact chamber  50 . Some airbag curtains  10  may be attached to a vehicle  12  by an attachment edge  46 . The inflatable curtain  10  may further include cushion segments  52  and dividers  54 . These segments  52  and dividers  54  allow control of the thickness of the curtain  10  when inflated, and thus serve to regulate the distance that the cushion  10  penetrates into the cabin of the vehicle  12  in the lateral direction  34 . Further, the dividers  54  may be placed to assure that a segment  52  of sufficient size and thickness is positioned to provide optimal protection to vehicle occupants in specific portions of the cabin of the vehicle  12 .  
         [0044]     The longitudinal fill chamber  40  of the inflatable curtain  10  may generally be positioned along an upper portion of the airbag cushion  10 , such as the attachment edge  46 . During deployment of the airbag cushion  10 , inflation gas is emitted from an airbag inflator  28 , which is often placed in the roof of a vehicle  12 . The inflation gas travels in a generally longitudinal direction  36  from an inflator end  42  of the airbag curtain  10  to a terminal end  44  of the curtain  10  through the longitudinal fill chamber  40  of the airbag curtain  10 . The inflation gas then travels downwardly in a transverse direction  38  to fill the contact chamber portion  50  of the inflatable curtain  10 .  
         [0045]     The inflatable curtain airbag cushion  10  further includes an inboard face  60  and an outboard face  62 . The inboard face  60  of the cushion  10  is positioned and configured to be contacted by a vehicle occupant. The outboard face  62  is positioned and configured for placement in abutment to the side door  20  and window  22  of the vehicle  12  when the airbag cushion  10  is deployed and inflated.  
         [0046]     In  FIG. 1 , the airbag cushion  10  is shown partially deployed and inflated. During ordinary use, such inflatable curtains  10  are generally stored folded in the roof  30  of a vehicle  12 , often along a roof rail (not shown) or similar structure. When deployed, the curtain  10  exits the roof  30  through roof trim  32  positioned to protect and cover the curtain  10  during ordinary operation of the vehicle  12 . The curtain  10  then deploys downward  11  in a substantially transverse direction  38 . As shown in  FIG. 1 , the deployed curtain  10  is positioned between the seat  24  and side door  20  and window  22 . Thus positioned, the curtain  10  can intervene between a vehicle occupant on the seat  24  and the side door  20  and window  22  to decelerate the vehicle occupant and prevent injury.  
         [0047]     As discussed briefly above, airbag curtains  10 , like other types of airbag cushions, are often deployed from structures in the vehicle  12  such as the steering wheel  18 , dashboard  14 , or the roof  30 . In some circumstances, such as with inflatable curtain airbags  10 , inflating airbag cushions must escape from trim structures such as roof trim  32 . Improper or partial deployment of the curtain  10 , such as when a portion of the curtain  10  is trapped in the roof  30  or roof trim  32  may reduce the protection provided to a vehicle occupant. Folding patterns were developed to assist the curtain  10  in deploying from the roof  30  of the vehicle.  
         [0048]     Some currently-known curtain folding methods include compression-folding the contact chamber  50  of the airbag cushion  10  from its bottom end toward the attachment edge  46 . At the attachment edge  46 , the cushion  10  is next given a single pleat fold in which the inboard and outboard faces  60 ,  62  are folded together to form a single “V-shaped” fold. In specific currently-used folding methods, the contact chamber  50  portion of the cushion is roll-folded, and the V-shaped fold was formed of at least a portion of the longitudinal fill chamber  40 . The V-shaped fold generally consists of a flattened section of the curtain which travels in the direction of the roll fold of the contact chamber portion  50  and a second flattened section at which the cushion  10  is creased and then folded back in the opposite direction. This folding method produces a configuration commonly referred to as the “roll-plus-one fold.” 
         [0049]     Airbag curtains folded according to the current roll-plus-one folding method have been known to fail during deployment, often by tearing. Applicants have discovered that this tearing often occurs along the crease formed in the roll-plus-one fold. Without being limited to any one theory, it is thought that during deployment, the center crease of the roll-plus-one fold of the curtain is placed under high stress. This high stress may cause the cushion to fail, thus compromising the ability of the cushion to protect a vehicle occupant.  
         [0050]     Referring to  FIGS. 2A-2D , a first folding method of the invention is illustrated.  FIG. 2A  illustrates an initial flattening step of a method of folding an airbag according to the invention. In  FIG. 2A , an inflatable curtain airbag cushion  10  is shown. As described in connection with  FIG. 1 , the curtain  10  includes an attachment edge  46  for attaching the cushion to a vehicle. The attachment edge  46  may include cushion attachments  48  adapted to allow a fastener or other means to pass through them into a portion of a recipient vehicle. One of ordinary skill in the art will understand that a wide variety of airbag attachment methods are available in the art and may be used with the attachment edge  46  of the invention to link the cushion  10  to a vehicle.  
         [0051]     The airbag curtain  10  further includes a longitudinal fill chamber  40  and a cushioning chamber  50 . In  FIG. 2A , the longitudinal fill chamber  40  is shown located in an upper portion of the cushion  10 . The longitudinal fill chamber is  40  is illustrated to be positioned between the attachment edge  46  and the contact cushion  60 . The fill chamber  40  is in fluid communication with the contact chamber  50 . During deployment of the cushion  10 , an inflation gas is injected into the airbag cushion  10  through a cushion inlet (omitted for clarity). The gas travels along the length of the fill chamber  40 , simultaneously filling the contact chamber  50 .  
         [0052]     As illustrated in  FIG. 2A , the contact chamber  50  may include segments  52  separated from each other by dividers  54 . The contact chamber  50  is bounded at its top by the longitudinal fill chamber  40  and at its bottom by a distal edge  56 . Segmenting the cushion  10  with dividers  54  may control the thickness of the deployed cushion  10 .  
         [0053]     In  FIG. 2A , the cushion  10  is shown flattened according to a first step of the folding methods of the invention. In this step, the inboard face  60  of the cushion is illustrated facing outward, while the outboard face  62  is not visible. This step prepares the cushion  10  for the remaining folding steps of the method.  
         [0054]     Referring next to  FIG. 2B , an airbag cushion  10  is shown partially folded according to a next step of the folding method of the invention. In this next step of the folding method, the contact chamber  50  is compression-folded to prepare it for placement in the vehicle. As used herein, the term “compression-fold” is used to describe any of a variety of folding methods in which the broad, flat cushion  10  is compressed in size to form a long, thickened, but narrowed configuration. According to the methods of the invention, the step of compression-folding the contact chamber portion  50  of the inflatable curtain airbag cushion  10  may include roll-folding.  
         [0055]     In some of the methods of the invention, roll-folding the airbag cushion  10  may comprise rolling the contact chamber portion  50  of the airbag cushion  10  toward the inboard face  60  of the airbag cushion  10 , as illustrated in  FIG. 2B . In others, roll-folding the airbag cushion  10  comprises rolling the contact chamber portion  50  of the airbag cushion  10  toward the outboard face  62  of the airbag cushion  10 . In alternate embodiments of the invention, the step of compression-folding the contact chamber portion  50  of the inflatable curtain airbag cushion  10  may include pleat-folding. In still others, the step of compression-folding the contact chamber portion  50  of the inflatable curtain airbag cushion  10  may include random folds generated by crumpling or vacuum-packing the cushion  10 .  
         [0056]     In  FIG. 2B , the inflatable curtain  10  is shown to be partially roll-folded, forming a roll fold  70  including the distal edge  56  and portions of the contact chamber  50  of the cushion  10 . The roll fold  70  illustrated in  FIG. 2B  was formed by rolling the contact chamber  50 , generally commencing at the distal edge  56 , against the inboard face  60  of the cushion  10 . This inboard-face oriented roll  70  will deploy into the cabin of a vehicle by unrolling toward a vehicle occupant. The compression-folding step illustrated in  FIG. 2B  is shown partially completed. In the methods of the invention, the roll-folding is often continued until the contact chamber  50  of the cushion  10  is rolled into the roll fold  70 .  
         [0057]     Referring next to  FIG. 2C , a next step of the folding methods of the invention is illustrated. In this step, the longitudinal fill chamber  40  is pleat-folded. More specifically, the inboard and outboard faces  60 ,  62  of the longitudinal fill chamber  40  of the airbag cushion  10  are individually pleated in this step. To accomplish this, the individual inboard and outboard faces  60 ,  62  are drawn away from each other and pleated, forming a pleat fold  80 . When completed, the pleat fold  80  includes an inboard pleat  82  and an outboard pleat  84 . The inboard pleat  82  includes a portion of the inboard face  60  of the cushion  10 . The inboard face  60  is here drawn outwardly, and then flattened such that interior surfaces of the inboard face  60  are positioned in abutment to each other. Similarly, the outboard pleat  82  includes a portion of the outboard face  62  of the cushion  10 . The outboard face  62  is here drawn outwardly and flattened such that interior surfaces of the outboard face  62  are positioned in abutment to each other.  
         [0058]      FIG. 2D  shows the configuration produced by the completion of the pleat-folding step of  FIG. 2C . In addition, in  FIG. 2D , the roll-fold  70  is tucked upwardly into the pleat fold  80 , resulting in a compact, tubular form for the curtain  10  suitable for being stowed in a roof of a vehicle. As further illustrated in  FIG. 2D , the individual inboard and outboard pleats  82 ,  84  may be wrapped about the roll fold  70  to further compact the curtain  10 .  
         [0059]      FIGS. 2E-2F  illustrate several possible variations on this folding method of the invention. More specifically,  FIG. 2E  illustrates an inflatable curtain airbag cushion  10  folded as illustrated in  FIGS. 2A-2D , with the exception that the roll fold  70  was produced by beginning at a distal edge  56  and rolling the curtain  10  toward the outboard face  62  of the curtain  10 . As previously illustrated, the roll fold  70  takes up substantially the entire contact chamber  50 . As in the previously discussed method, the longitudinal fill chamber  40  is pleat-folded. More specifically, the inboard and outboard faces  60 ,  62  of the longitudinal fill chamber  40  of the airbag cushion  10  are individually pleat folded to form a pleat  80 . To form the pleat  80 , the individual inboard and outboard faces  60 ,  62  are drawn away from each other and folded against themselves to form individual inboard and outboard pleats  82 ,  84 . When completed, the pleat fold  80  includes an inboard pleat  82  and an outboard pleat  84 . The inboard pleat  82  includes a portion of the inboard face  60  of the cushion  10 . The inboard face  60  is here drawn outwardly, and then flattened such that interior surfaces of the inboard face  60  are positioned in abutment to each other. Similarly, the outboard pleat  82  includes a portion of the outboard face  62  of the cushion  10 . The outboard face  62  is here drawn outwardly and flattened such that interior surfaces of the outboard face  62  are positioned in abutment to each other.  
         [0060]      FIG. 2F  shows the final folded configuration of an airbag curtain  10  produced in yet another alternate folding method of the invention similar to that illustrated in  FIGS. 2A-2D . In this alternate folding method, the contact chamber  50  is compression-folded by accordion-folding instead of rolling. Thus, in this alternate method, beginning at the distal edge  56 , the contact chamber  50  is pleated to form accordion folds  90 . As previously illustrated, the accordion folds  90  take up substantially the entire contact chamber  50 . Alternate folding method such as vacuum-compression and random folding may be substituted for rolling and accordion-folding. In these more random folding methods, a specific end form of the cushion  10  may be specified, and the cushion may then be compressed accordingly. This may add further flexibility in vehicle design. The longitudinal fill chamber  40  is next pleat-folded as discussed above. Specifically, the inboard and outboard faces  60 ,  62  of the longitudinal fill chamber  40  of the airbag cushion  10  are individually pleat folded. The final pleat  80  is formed by drawing the individual inboard and outboard faces  60 ,  62  of the longitudinal fill chamber  40  away from each other and flattening them. When completed, the pleat fold  80  includes an inboard pleat  82  and an outboard pleat  84 . The inboard pleat  82  includes a portion of the inboard face  60  of the cushion  10 . The inboard face  60  is here drawn outwardly, and then flattened such that interior surfaces of the inboard face  60  are positioned in abutment to each other. Similarly, the outboard pleat  82  includes a portion of the outboard face  62  of the cushion  10 . The outboard face  62  is here drawn outwardly and flattened such that interior surfaces of the outboard face  62  are positioned in abutment to each other.  
         [0061]      FIGS. 3A-3D  illustrate another embodiment of the inflatable curtain folding methods of the invention, in which the folds produced may aid deployment of the cushion  110  without placing high stress on the longitudinal fill chamber portion  140  of the cushion  110 .  
         [0062]     Referring first to  FIG. 3A , an initial flattening step of this folding method is illustrated. The curtain  110  is similar to that described in connection with  FIGS. 1 and 2 A- 2 F. The cushion  110  first includes an attachment edge  146  for attaching the cushion  110  to a vehicle. The attachment edge  146  may include cushion attachments  148  adapted to allow a fastener or other means to pass through them into a portion of a recipient vehicle to mount the cushion  110  to the vehicle. One of ordinary skill in the art will understand that a wide variety of airbag attachment methods and apparatus are available in the art and may be used with the attachment edge  146  of the invention to link the cushion  110  to a vehicle.  
         [0063]     The airbag curtain  110  further includes a longitudinal fill chamber  140  and a cushioning chamber  150 . In  FIG. 3A , the longitudinal fill chamber  140  is shown located in an upper portion of the cushion  110 . The longitudinal fill chamber  140  is illustrated to be positioned between the attachment edge  146  and the contact cushion  150 . The fill chamber  140  is in fluid communication with the contact chamber  150 . During deployment of the cushion  110 , an inflation gas is injected into the airbag cushion  110  through a cushion inlet (omitted for clarity). The gas travels along the length of the fill chamber  140 , simultaneously beginning to fill the contact chamber  150 .  
         [0064]     As illustrated in  FIG. 3A , the contact chamber  150  may include segments  152  separated from each other by dividers  154 . The contact chamber  150  is bounded at its top by the longitudinal fill chamber  140  and at its bottom by a distal edge  156 . Providing segments in the cushion  110  may help to control the thickness of the deployed cushion  110 .  
         [0065]     In  FIG. 3A , the cushion  110  is shown flattened according to a first step of the folding methods of the invention. In this step, the inboard face  160  of the cushion is illustrated facing outward, while the outboard face  162  is not visible. This step prepares the cushion  110  for the remaining folding steps of the method.  
         [0066]     Referring next to  FIG. 3B , an airbag cushion  110  is shown partially folded according to a next step of the folding method of the invention in which the contact chamber  150  is compression-folded. As discussed above, the term “compression-fold” is used to describe any of a variety of folding methods in which the broad, flattened cushion is compressed in size to form a long, thickened, but narrow configuration. According to the methods of the invention, the step of compression-folding the contact chamber portion  150  of the inflatable curtain airbag cushion  110  may include roll-folding. In some of the methods of the invention, roll-folding the airbag cushion  110  may comprise rolling the contact chamber portion  150  of the airbag cushion  110  toward the inboard face  160  of the airbag cushion  110 . In others as illustrated in  FIG. 3B , roll-folding the airbag cushion  110  comprises rolling the contact chamber portion  150  of the airbag cushion  110  toward the outboard face  162  of the airbag cushion  110 .  
         [0067]     In alternate embodiments of the invention, the step of compression-folding the contact chamber portion  150  of the inflatable curtain airbag cushion  110  may include pleat-folding. In still others, the step of compression-folding the contact chamber portion  150  of the inflatable curtain airbag cushion  110  may include random folds generated by crumpling or vacuum-packing the cushion  110 . In these more random folding methods, a specific end form of the cushion  10  may be specified, and the cushion may then be compressed accordingly. This may add further flexibility in vehicle design.  
         [0068]     In  FIG. 3B , the inflatable curtain  110  is shown to be partially roll-folded, forming a roll fold  170  including the distal edge  156  and portions of the contact chamber  150  of the cushion  110 . The roll fold  170  illustrated in  FIG. 3B  was formed by rolling the contact chamber  150 , generally commencing at about the distal edge  156 , against the outboard face  162  of the cushion  110 . This outboard face-oriented roll  170  will deploy into the cabin of a vehicle by unrolling away from a vehicle occupant. The compression-folding step illustrated in  FIG. 3B  is shown partially completed. In the methods of the invention, the roll-folding may be continued until the contact chamber  150  of the cushion  110  is about completely rolled into the roll fold  170 .  
         [0069]     Referring next to  FIG. 3C , a next step of the folding methods of the invention is illustrated in which the longitudinal fill chamber  140  is pleat-folded. More specifically,  FIG. 3C  illustrates a step of individually pleat-folding the inboard and outboard faces  160 ,  162  of the longitudinal fill chamber  140  of the airbag cushion  110 . In this step, the individual inboard and outboard faces  160 ,  162  are drawn away from each other and pleated, forming a pleat fold  180 . When completed, the pleat fold  180  includes an inboard pleat  182  and an outboard pleat  184 . The inboard pleat  182  includes a portion of the inboard face  160  of the cushion  110 . The inboard face  160  is here drawn outwardly, and then flattened such that interior surfaces of the inboard face  160  are positioned in abutment to each other. Similarly, the outboard pleat  182  includes a portion of the outboard face  162  of the cushion  110 . The outboard face  162  is here drawn outwardly and flattened such that interior surfaces of the outboard face  162  are positioned in abutment to each other.  
         [0070]      FIG. 3D  shows the configuration produced by the completion of the pleat-folding step of  FIG. 3C . In  FIG. 3D , the inboard and outboard pleats  182 ,  184  are folded upwardly toward the attachment edge  146 . In addition, the roll-fold  170  is wrapped upwardly and placed against the pleat fold  180 , resulting in a compact, tubular form suitable for being stowed in a roof of a vehicle, as illustrated in  FIG. 1 . The individual roll fold  170  may be placed against either the inboard or outboard pleat  182 ,  184 . In  FIG. 3D , the roll fold  170  is shown placed against the inboard pleat  182 .  
         [0071]      FIGS. 3E-3F  illustrate several possible variations on this folding method of the invention. More specifically,  FIG. 2E  illustrates an inflatable curtain airbag cushion  10  folded as illustrated in  FIGS. 3A-3D , with the exception that the roll fold  170  was produced by beginning at a distal edge  156  and rolling the curtain  110  toward the inboard face  160  of the curtain  110 . As previously illustrated, the roll fold  170  takes up substantially the entire contact chamber  150 . As in the other method, the longitudinal fill chamber  140  is pleat-folded. More specifically, the inboard and outboard faces  160 ,  162  of the longitudinal fill chamber  140  of the airbag cushion  110  are individually pleat-folded to form a pleat  180 . To form the pleat  180 , the individual inboard and outboard faces  160 ,  162  are drawn away from each other and pleated. When completed, the pleat fold  180  includes an inboard pleat  182  and an outboard pleat  184 . The inboard pleat  182  includes a portion of the inboard face  160  of the cushion  110 . The inboard face  160  is here drawn outwardly, and then flattened such that interior surfaces of the inboard face  160  are positioned in abutment to each other. Similarly, the outboard pleat  182  includes a portion of the outboard face  162  of the cushion  110 . The outboard face  162  is here drawn outwardly and flattened such that interior surfaces of the outboard face  162  are positioned in abutment to each other.  FIG. 3E  also illustrates a variation in a fixed step of the method, showing the roll fold  12   e  placed equal the outboard pleat  184  of the folded curtain  10 .  
         [0072]      FIG. 3F  shows the final folded configuration of an airbag curtain  110  produced in yet another alternate folding method of the invention similar to that illustrated in  FIGS. 3A-3D . In this alternate folding method, the contact chamber  150  is compression-folded by accordion-folding instead of rolling. Thus, in this alternate method, beginning at the distal edge  156 , the contact chamber  150  is pleated to form accordion folds  190 . As previously illustrated, the accordion folds  190  take up substantially the entire contact chamber  150 . The longitudinal fill chamber  140  is next pleat-folded as discussed above. Specifically, the inboard and outboard faces  160 ,  162  of the longitudinal fill chamber  140  of the airbag cushion  110  are individually pleat folded to form a pleat  180 .  
         [0073]     To form the pleat  180 , the individual inboard and outboard faces  160 ,  162  of the longitudinal fill chamber  140  are drawn away from each other and pleated. When completed, the pleat fold  180  includes an inboard pleat  182  and an outboard pleat  184 . The inboard pleat  182  includes a portion of the inboard face  160  of the cushion  110 . The inboard face  160  is here drawn outwardly, and then flattened such that interior surfaces of the inboard face  160  are positioned in abutment to each other. Similarly, the outboard pleat  182  includes a portion of the outboard face  162  of the cushion  110 . The outboard face  162  is here drawn outwardly and flattened such that interior surfaces of the outboard face  162  are positioned in abutment to each other. As above, the compression-folded contact chamber portion  150  is then drawn upwardly and placed against the inboard pleat  182  of the cushion  110 .  
         [0074]     In summary, the present invention provides a family of folding methods and patterns for folding an inflatable curtain airbag cushion. These folding methods and patterns assist in the deployment of the airbag curtain. More specifically, the folding methods and patterns of the invention may allow an airbag cushion to be deployed without placing high stress on the longitudinal fill chamber of the airbag cushion.  
         [0075]     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. More specifically, one of skill in the art will understand that the order and magnitude of the pleats, roll-folds, accordion-folds and other folds produced may be modified to alter the deployment characteristics of the airbag cushion. Thus, 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.