Patent Publication Number: US-2004053764-A1

Title: Toroidal air bag folding apparatus

Description:
BACKGROUND AND SUMMARY OF THE INVENTION  
       [0001] The present invention generally relates to a machine and method of folding or compacting an air bag and more particularly a machine and method for compacting an air bag directly into its deployment cover.  
       [0002] A driver side air bag module often includes a cover, housing, air bag, a cushion retainer and inflator. The typical way of assembling an air bag module is to insert the retainer within the central opening of the air bag and then to mount the retainer and air bag to the housing. Thereafter, the air bag is precisely folded into the housing. Subsequently, the cover is attached to the housing. As a final step in the manufacturing process, the inflator is inserted and secured to the housing. The prior art has also proposed to fold an air bag in an arbitrary or chaotic manner and then take this folded air bag and insert it into an air bag housing in a conventional way.  
       [0003] The present invention proposes to fold a toroidal air bag in an arbitrary or chaotic manner but to insert this folded air bag into the cover, and to use a piston coaxially aligned with a ram plate in the folding shape within the apparatus to dispose the folded cushion in a toroidal module. Disclosed is a simple means of folding an air bag and does so in an ergonomic manner offering greater efficiencies. It is an object of the present invention to provide an apparatus for folding an air bag that is convenient to use.  
       [0004] Accordingly, the invention comprises a folding apparatus for inserting an air bag into an interior cavity of a cover. In the preferred embodiment, the air bag is attached to a cushion retainer and inflator before it is inserted into the cover. The apparatus comprises a straight tube, the tube sized in cross-section to slidably receive a ram plate. The cross-section further is configured to substantially conform to the cross-section of an interior cavity defined by the module deployment cover. The tube includes a pair of open ends oriented so that a plane of the tube is substantially parallel to vertical although other configurations are within the scope of the invention. The folding apparatus includes a ram apparatus movable through the tube and adapted to hold and move a ram plate and air bag through the tube. When moved in one direction, the ram apparatus moves the air bag into the cover. The folding apparatus further contains a lower movable piston, which functions as an interior cushion support and is passed through a hole in the air bag module cover. The folding apparatus additionally includes a holding fixture for orienting the cover so that its internal cavity is in alignment with and adjacent to the tube such that the housing and air bag can be rammed into the cover internal cavity.  
       [0005] Many other objects and purposes of the invention will be clear from the following detailed description of the drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006]FIG. 1 is an exploded view of a typical driver side air bag module;  
     [0007]FIG. 2 is a rear plan view of an assembled module;  
     [0008]FIG. 2A is a cross-sectional view of an assembled driver side air bag module through section line  2 A- 2 A of FIG. 2;  
     [0009]FIG. 2B is a diagrammatic view of a neck portion of an air bag;  
     [0010]FIG. 3 is a diagrammatic view of the major components of a folding apparatus;  
     [0011]FIG. 4 is a diagrammatic view of a tube component according to the teachings of the present invention;  
     [0012]FIG. 5 is a perspective view of the first end of the tube according to the teachings of the present invention;  
     [0013]FIG. 6 is a perspective view of a second end of the tube according to the teachings of the present invention;  
     [0014]FIG. 7 is a perspective view of the ram according to the teachings of the present invention;  
     [0015]FIG. 8 is an end view of the ram plate according to the teachings of the present invention;  
     [0016]FIG. 9 is a perspective view of the piston according to the teachings of the present invention;  
     [0017]FIG. 10 is a top perspective view of the piston according to the teachings of the present invention;  
     [0018]FIG. 11 is a top perspective view of the cover holding fixture according to the teachings of the present invention;  
     [0019]FIG. 12 is a top view of the fixture according to FIG. 11 holding an air bag cover;  
     [0020]FIG. 13 depicts a coupling of a module cushion retaining member to the piston;  
     [0021]FIG. 14 describes coupling a cushion over the piston and cushion retaining member;  
     [0022]FIG. 15 depicts the disposing of an air bag inflator within the cushion and onto the cushion retaining member;  
     [0023]FIG. 16 depicts the coupling of the ram onto the mounting plate;  
     [0024]FIG. 17 depicts the positioning of the tube around the cushion, ram subassembly;  
     [0025]FIG. 18 depicts the coupling of the tube and piston to the fixture;  
     [0026]FIG. 19 depicts the side close-up view of the tube coupled to the fixture;  
     [0027]FIG. 20 shows the compression of the cushion into the cover;  
     [0028]FIG. 21 shows the ram disposed within the cover according to the teachings of the present invention;  
     [0029]FIG. 22 represents the bottom view of the fixture containing a module having a cushion disposed therein;  
     [0030]FIG. 23 depicts a folding cushion after the ram is removed;  
     [0031]FIG. 24 depicts removal of a pair of cover retaining apparatus;  
     [0032]FIG. 25 depicts a coupling of a cover flange over the retaining studs; and  
     [0033]FIG. 26 depicts the coupling of the module housing to the cover/cushion subassembly. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
     [0034] Referring generally to FIGS. 1 through 2B, an air bag module  30  is shown. The air bag module  30  includes a housing  32  coupled to a steering wheel armature  34 . A cover  36  is retained by either the housing  32  or the steering wheel armature  38  utilizing standard fasteners  40 . The retainer  44  functions to hold electronic components at a surface  46  of the cover  36 . Additionally, the retainer  44  functions as a bracket to hold the toroidal air bag  48  and inflator  50  within the module  30 . The toroidal air bag and inflator are coupled to the housing  32  of air bag module  30  using standard coupling studs  45  on the cushion retainer  44 .  
     [0035] The cover  36  is generally made from thermoplastic olefin or a thermoplastic elastomer, and has a plurality of retaining apertures  34 , which are used to couple the cover  36  to the mounting plate  12 . The cover  36  defines a central aperture  42 , which is used to expose an air bag retainer  44  disposed within the module  30  and a cover cavity  43 .  
     [0036] The toroidal air bag  48  has an internal neck portion  52  with a central opening  54  and a plurality of openings  56 , which are used to couple the toroidal air bag  48  to retainer  44 . Inflator  50  comprises a mounting flange  58  with a plurality of mounting openings  60 . The inflator  50  includes a body  62  in which propellant and/or inflation gas is located and the body has at least one but usually includes a plurality of exit ports  64 .  
     [0037] As previously indicated, a typical way of assembling an air bag module  30  is to insert the retainer (retaining ring) within the central opening  64  of the air bag  48  and then to carefully fold the air bag. Thereafter, an optional fabric or paper covering (such as Tyvek®) may be used to envelop the folded cushion to maintain the fold during the subsequent handling of the folded bag. Thereafter, the folded air bag is inserted into the housing. Subsequently, the cover  36  is attached to the housing. Thereafter, the inflator is inserted and secured to the housing.  
     [0038] Reference is made to FIG. 3, which illustrates the folding apparatus  70 , which is designed to compress and insert an air bag  48  within an interior cavity  72  of the cover  36 . The cover  36  is typically formed of four walls  74 , which surround an air bag cover door  76 . In this regard, the door  76  has a defined through hole  78 , which functions to accept the associated retainer as described in co-pending application Ser. No. 09/871,037, hereby incorporated by reference.  
     [0039] The folding apparatus  70  comprises a straight tube  80 , a ram  82 , a lower movable piston member  84 , an upper movable piston member  85 , and a base fixture  86 . The tube  80  is preferably made of transparent LEXAN®, which will enable most folding operations to be visible by an attending operator.  
     [0040] Reference is now made to FIGS.  4 - 6 , which show the tube  80 . The cross-section of the tube conforms to the cross-section of the cavity  72  of the module cover  36 . The tube  80  defines a coupling structure  88  at its first end  90 . The coupling structure  88  defines a plurality of holes  92  configured to accept pins  94  disposed on the fixture  86 . Further defined on the coupling structure  88  is a pair of parallel slots  96 , which accept a pair of separator plates  98  (as described later).  
     [0041]FIG. 6 depicts a perspective view of the second end  100  of the tube  80 . Defined at the second end  100  is an end plate  102  with an orifice  104  configured to slidably accept the exterior surface  106  of the ram  82 . Defined within the orifice  104  is a plurality of notches  108  configured to be mated with a plurality of flanges  110  disposed on the exterior surface  106  of the ram  82 .  
     [0042]FIGS. 7 and 8 depict a perspective end view of the ram  82 . The ram  82 , which is configured to be moved through and out of the tube  80 , is a generally cylindrical body  112  having a ram plate  114  disposed at one end  116 . The ram plate  114  has an exterior periphery  118 , which substantially conforms to the interior cross-section  120  of the tube  80 . Disposed on the exterior surface  106  of the ram  82  is a plurality of flanges  110 , which mate with the notches  108  defined in the orifice  104  of the end plate  102 . The notches  108  and flanges  110  allow the full retraction of the ram plate  114  within the tube  80 . FIG. 8 depicts an end view of the ram  82 . As can be seen, the ram plate  114  defines an inner bore  122 , which substantially conforms to the exterior surface  106  of the ram  82 . The ram plate  114  is coupled to the ram body  112  by use of through fasteners  124 , which couple the ram plate  114  to the flanges  110  defined at the end of the tubular body. Defined at the end of the ram body  112  is a plurality of cutouts  126  whose function is described below.  
     [0043]FIGS. 9 and 10 represent the piston member  84 . The piston member  84  is a member that is slidably received through the hole  78  defined in the fixture  86  and through hole  78  of cover  36 . Defined at the first end  128  of the piston  84  is a plurality of notches  130 , which slidably couple with the retainer  44  of the module  30 . In this regard, the exterior periphery  132  of the first end  128  substantially conforms to the interior surface  134  of the retainer  44 .  
     [0044]FIG. 11 depicts a top view of the fixture. Shown defined within the fixture  86  is a cavity  136 , which conforms to the shape of the module cover  36 . Further defined within the fixture  86  are a second pair of parallel slots  137 , which are configured to be aligned with the slots  96  defined on the mounting assembly of the tube  80 .  
     [0045] FIGS.  12 - 25  represent the methods associated with the assembly of an air bag module  30  according to the teachings of the present invention. FIG. 12 depicts the insertion of the cover  36  within the fixture  86 . A pair of separator plates  98  is disposed within the slots  137  of the fixture  86 . As can be seen, the separator plates  98  function to hold the cover  36  within the cavity  136  as well as to hold the pair of retaining flanges  140  of the cover  30  in a position that allows for the insertion of the toroidal air bag  48 .  
     [0046] As can be seen, the through-hole  78  defined through the cover  36  and the fixture  86  are coaxial and have substantially the same radius. These both function to slidably accept the piston member  84 , as will be further described below.  
     [0047]FIG. 13 depicts the mounting of the retainer  44  onto the first end  128  of the piston  84 . The notches  130  of the first end  128  (see FIG. 9) are interleaved with the corresponding notches defined on the interior  134  of the retainer  44 . As can be seen, the retainer  44  has four mounting studs  45 , which are used to couple the toroidal air bag  48  and couple it to the module  30 .  
     [0048]FIG. 14 depicts the positioning of the toroidal air bag  48  over the piston  84 . In this regard, the internal neck portion  52  of the toroidal air bag  48  is annularly disposed over and around the piston  84 . The retaining studs  45  of the retainer  44  are positioned through the holes  56  of the toroidal air bag  48 , encasing the retainer  44  within the interior neck portion  52 . The piston  84  is positioned within the hole  78  defined by the fixture  86  and cover  36 .  
     [0049]FIG. 15 depicts the insertion of the module inflator within the cushion. The studs  45  are positioned through a second set of four holes disposed within the body of the toroidal cushion  48 . FIG. 16 depicts the coupling of the ram  82  to the studs  45  of the retainer  44 . While the ram plate  114  is shown being coupled to the studs  45  using wing nuts, it is envisioned that an automated system encompassing pneumatic controlled fasteners or clamps can be used.  
     [0050]FIGS. 17 and 18 depict the positioning of the tube  80  over the ram  82 , piston  84 , and toroidal cushion  48 . At this point, the tube  80  is brought into locking contact with the fixture  86  utilizing the pins  94 . As best seen in FIG. 18, when the tube  80  is brought down onto the fixture  86 , the ram plate  114  is held stationary and is positioned adjacent to the second end of the tube  80 .  
     [0051]FIG. 19 depicts a close-up side view of the mating of the tube  80  with the fixture  86 . Shown are the separating plates, which are used to place the air bag module cover  36  in its proper orientation.  
     [0052]FIG. 20 depicts the pushing down of the ram  82  and piston  84  through the tube  80 . As can be seen, the ram plate  114  forces the toroidal air bag  48  into the cavity  72  of the cover. Prior to allowing the ram plate  114  to move, the upper piston  85  is brought nearly into contact with the lower piston  84 , so that the air bag  48  and retainer  44  are sandwiched between the two pistons. In this manner, the piston  84  prevents the toroidal air bag  48  from being extruded through the hole  78 , while the piston  85  creates an inflator installation pocket within the scrunch folded cushion.  
     [0053]FIG. 21 depicts the toroidal air bag  48  folding assembly with the tube  80  removed. As can be seen, the toroidal air bag  48  has been compressed within the cavity of the module cover  36  and the ram plate  114  is forcing the cushion within the cover  36 . As can be seen, the folded air bag  48  is annularly disposed about the retainer  44 .  
     [0054]FIG. 22 depicts a bottom view of the cushion folding mechanism. As can be seen, the piston  84  becomes detached from the retainer  44 , leaving the hole defined by the fixture empty. It is envisioned the piston can be actuated up through the hole pneumatically after the module assembly  30  has been removed from the fixture  86 .  
     [0055]FIG. 23 shows the module assembly after the ram has been removed from the mounting studs. As can be seen, the separator plates hold the flanges of the cover away from the mounting studs. FIG. 24 depicts the cover flanges being disposed over the mounting studs after the separator plates have been removed. FIG. 25 shows the positioning of the cover flanges over the studs of retainer  44 . FIG. 26 depicts the coupling of the housing base plate onto the module.  
     [0056] Many changes and modifications in the above-described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, that scope is intended to be limited only by the scope of the appended claims.