Abstract:
Inflatable devices such as airbags are detailed. The bags may be formed of components well nested on linear rolls of material, reducing material wastage. The airbags additionally may, in some cases, be formed of components lacking curved surfaces; in certain cases the bag components additionally may have complementary surfaces that, although formed of straight segments, resemble convex and concave shapes.

Description:
FIELD OF THE INVENTION 
     This invention relates to inflatable devices, components of such devices, and methods of forming the devices from the components. More particularly (but not exclusively), the invention relates to occupant airbags for passenger vehicles and techniques for manufacturing the bags. 
     BACKGROUND OF THE INVENTION 
     Certain current airbags for passenger vehicles frequently comprise two circular pieces of fabric sewn or woven together. Because the fabric from which the airbags are made typically is supplied in linear rolls, substantial waste remains after circular pieces are cut from the linear rolls. Indeed, useful bag surface obtained from the total surface available on a roll is usually no greater than eighty-seven percent, resulting in waste equivalent to at least thirteen percent of the total available fabric. 
     Whether or not circular, two-panel airbags often are used for front-seat passengers because they are easy to produce, in that they may be sewn flat at their perimeters or peripheries. Generally, however, these bags are not well adapted for placement in automobile dashboards, potentially degrading deployment and stability during occupant impact. Consequently, three-panel bags have been designed for better correspondence with dashboard surfaces. 
     Such three-panel bags may comprise two lateral panels of identical shape and one frontal panel of different shape. Including multiple panels of different shapes complicates the design, though, increasing assembly difficulty. Further, fabric consumption likely will be greater than for simpler designs, as nesting of multiple, complex shapes on linear rolls is difficult. 
     Needed, therefore, are airbag designs permitting more efficient usage of fabric or similar materials from which they are constructed. For at least some bags, further, needed are designs well fitted to complement surfaces of dashboards of automobiles. Such airbags additionally should, if possible, be easy to assemble. 
     SUMMARY OF THE INVENTION 
     The present invention fulfills (at least) these needs. Techniques of the present invention provide improved nesting of component pieces on linear or other rolls of material without sacrificing ease of assembly. They also supply three-dimensional assemblies for use with, in particular, front-seat passengers, with the assemblies allowing for satisfactory stability of the bags when associated with vehicle dashboards. Such three-dimensional assemblies, moreover, are relatively easy to form and have components that nest well on linear or other fabric rolls, particularly for bonding assembly. 
     Certain embodiments of the invention incorporate use of rectangular (including square) components, in lieu of circular ones, to form airbags of octagonal shape. The collective set of components may utilize an entire linear roll of fabric with little or no cutting waste. Through folding and other manipulation of the rectangular components, an octagonal shape may be devised for the inflatable airbag. Alternatively, compound component shapes including rectangles and other polygons (but preferably not curved surfaces) may be used instead of some rectangles, again with less waste than conventional solutions. 
     Other embodiments of the invention likewise utilize straight-line surfaces from which complementary substitutes for curved convex and concave surfaces may be created without waste of fabric. Components including these surfaces may then be assembled to form a generally curved structure that is relatively stable when deployed between a dashboard and vehicle occupant. 
     It thus is an optional, non-exclusive object of the present invention to provide inflatable devices able to be formed with reduced waste of construction materials. 
     It is another optional, non-exclusive object of the present invention to provide inflatable devices, in the form of airbags, that are easy to assemble. 
     It is also an optional, non-exclusive object of the present invention to provide airbags utilizing components that are non-circular in shape. 
     It is a further optional, non-exclusive object of the present invention to provide airbags having panels formed of fabric shaped as rectangles, other polygons, or other compound shapes. 
     It is, moreover, an optional, non-exclusive object of the present invention to provide airbags having generally octagonal shape or other shapes lacking curved edges. 
     It is an additional optional, non-exclusive object of the present invention to provide airbags using panels having complementary pseudo-curved surfaces. 
     It is yet another optional, non-exclusive object of the present invention to provide airbags having curved structure when inflated yet relatively stably-positioned with respect to dashboards or other areas from which they deploy. 
     Other objects, features, and advantages of the present invention will be apparent to those skilled in the relevant art with reference to the remaining text and drawings of this application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of an exemplary linear strip of material showing a pattern from which conventional circular components may be cut. 
         FIG. 2  is a plan view of an exemplary rectangular component showing folds which may be made during construction of an airbag. 
         FIG. 3  is a plan view of the component of  FIG. 2  together with other components which may be assembled into an octagonally-shaped airbag. 
         FIG. 4  is a plan view of an exemplary linear strip of material showing a pattern from which components such as those depicted in  FIGS. 2-3  may be cut. 
         FIG. 4A  illustrates alternate patterns from which components may be cut. 
         FIGS. 5A-C  are plan views of first alternate components which may be assembled into an octagonally-shaped airbag. 
         FIG. 6  is a plan view of a first alternate exemplary linear strip of material showing a pattern from which components such as those depicted in  FIGS. 5A-C  may be cut. 
         FIGS. 7A-C  are plan views of second alternate components which may be assembled into an octagonally-shaped airbag. 
         FIGS. 8A-B  are plan views of second alternate exemplary linear strips of material showing patterns from which components such as those depicted in  FIGS. 7A-C  may be cut. 
         FIGS. 9A-B  are plan views of two panels of materials cut to form airbag components having complementary pseudo-convex and -concave surfaces. 
         FIG. 9C  is a plan view of an assembly of two components of  FIGS. 9A-B  having pseudo-concave surfaces. 
         FIGS. 10A-D  are plan views of an airbag constructed of the components of  FIGS. 9A-C . 
         FIG. 11A  is a plan view of an exemplary linear strip from which alternate components having pseudo-convex and -concave surfaces may be cut. 
         FIG. 11B  is a plan view of the alternate components of  FIG. 11A . 
     
    
    
     DETAILED DESCRIPTION 
     Depicted in  FIG. 1  is an example of a linear strip  10  of fabric or other material  14  from which airbag components may be removed. Strip  10  typically is, but need not necessarily be, part of a roll of material  14 . Similarly, strip  10  usually has parallel edges  18  and  22  and a selected width W. Material  14  beneficially comprises fabric sufficiently impervious to air or other inflation fluid so as to allow the airbag of which it is made to deploy successfully. 
     Also detailed in  FIG. 1  are a series of circular patterns  26  providing guidance for forming circular airbag panels. Patterns  26  are nested, or positioned, along strip  10  so as to minimize unused (wasted) material  14 . Although such nesting may optimize utilization of material  14 , the fact that circular patterns  26  are employed results in only approximately eighty-seven percent (or less) of material  14  being beneficially used. In particular, because each piece cut consistent with patterns  26  will have a curved, circular periphery, it must be positioned tangent to adjacent pieces along strip  10 —rather than abutting such adjacent pieces along most or all of its periphery. 
       FIG. 2  shows component  30  cut from a pattern that forms an alternative to pattern  26 . Component  30  is in the form of a square or other rectangle and, notably, lacks any curvature in its periphery. Although conceivably alternatives to pattern  30  with some peripheral curvature could be designed, preferred at present is that pattern  30  define only straight-line peripheries. Consequently, along strip  10  the pattern for component  30  may abut other patterns with straight-line peripheries along a length substantially greater than if the peripheries were only tangent. 
     Illustrated in  FIG. 3  are additional components  34 A,  34 B, and  38 . Each of these additional components  34 A-B and  38  is rectangular in shape and thus, like component  30 , includes only straight-line peripheries. As detailed in  FIG. 3 , components  30 ,  34 A-B, and  38  may be assembled to form an octagonally-shaped airbag  42 . 
     To create airbag  42 , triangular corners  46 A-D of component  30  may be folded atop central portion  50  of the component  30  (as shown for corner  46 A in  FIG. 2  and for all corners  46 A-D in  FIG. 3 ). Such folding creates an octagonal periphery for component  30 . Components  34 A-B and  38  may then be connected to each other in a cruciform shape and connected to corners  46 A-D to form the enclosed octagonal structure of airbag  42 . (Airbag  42  thereafter may be processed to incorporate or be linked to an inflation mechanism for use in vehicles.) 
     In particular, each of edges  50 A-B of component  34 A, edges  54 A-B of component  34 B, and edges  58 A-H of corners  46 A-D has approximately (or identically) the same length. Likewise, each of edges  50 C-D of component  34 A and edges  54 C-D of component  34 B has approximately or identically the same length. Edges  62 A-B of component  38  have length approximately or identically equal to the sum of the lengths of edges  58 A,  50 D, and  58 D, for example, while edges  62 C-D each have approximately or identically the same length as edges  30 B and  30 D. Finally, the lengths of edges  50 C and  54 D may approximately or identically match those of edges  30 A and  30 C. 
     Accordingly, to create airbag  42 :
         1. edge  50 A may be connected to edge  58 C;   2. edge  50 B may be connected to edge  58 B;   3. edge  50 C may be connected to edge  30 A;   4. edge  54 A may be connected to edge  58 F;   5. edge  54 B may be connected to edge  58 G;   6. edge  54 D may be connected to edge  30 C;   7. edge  62 C may be connected to edge  30 B;   8. edge  62 D may be connected to edge  30 D;   9. edge  62 A may be connected to edges  58 D,  50 D, and  58 A; and   10. edge  62 B may be connected to edges  58 E,  54 C, and  58 H.
 
These connections may be made in any desired sequence and advantageously may occur through sewing, bonding, or welding of material  14  (and either with or without additional connection strips). Those skilled in the relevant art will, however, recognize that any connection means suitable for use with material  14  may be used instead.
       

     Disclosed in  FIG. 4  are patterns  78  from which pieces such as components  30 ,  34 A-B, and  38  may be cut from strip  10  of material  14  with little waste. By contrast with  FIG. 1 ,  FIG. 4  illustrates only small areas  82  of waste existing in strip  10  between patterns  78 . Areas  82  clearly constitute substantially less than thirteen percent of the surface area of strip  10 ; consequently, greater efficiency in use of material  14  may be achieved. 
       FIGS. 5A-C  detail an alternate assembly technique for an octagonally-shaped airbag  42 A. Airbag  42 A again may comprise component  38 . However, rather than also including components  30  and  34 A-B, airbag  42 A additionally comprises (a single) component  66  of complex polygonal shape. Component  66  preferably has straight edges and corners  70 A-D which may be folded as depicted in  FIG. 5B . Edges of the corners  70 A-D thereafter may be connected to component  38 , corner  70 A may be connected to corner  70 D, and corner  70 B may be connected to corner  70 C to form airbag  42 A (as shown in  FIGS. 5B-C ). Illustrated in  FIG. 6  are patterns  74  from which pieces such as components  38  and  66  may be cut from strip  10 A of material  14 , again with substantially less waste  82 A than currently exists. 
     Detailed in  FIGS. 7A-C  is another alternate assembly technique for an octagonally-shaped airbag  42 B. Airbag  42 B may be formed of components  200  and  204 , with component  200  being octagonal in shape and component  204  being generally so. Specifically, however, component  204  is of complex polygonal shape, with (preferably) eight rectangular edge sections  208 A-H that may be folded over and attached to component  200  to create airbag  42 B.  FIGS. 8A-B  illustrate respective patterns  212  and  216  from which components  200  and  204  may be cut from strips  10 B-C of material with little waste  82 B-C. 
       FIGS. 9A-10D  depict creation of an alternative airbag  86 . Designed principally (although not necessarily exclusively) for protection of non-driver, front-seat vehicle passengers, airbag  86  is configured for enhanced stability when deployed from a dashboard D (or other location). Components of airbag  86  also nest well on strips  10 . 
     Illustrated in  FIG. 9A  are panels  90  and  94 , which may be cut from strip  10 . If adjacent on strip  10 , panels  90  and  94  may share common (straight) edge  98  prior to separation. In preferred versions of airbag  86 , panels  90  and  94  are polygons, being substantially rectangular in shape but with tapered corners  99 A-D and  100 A-D. A generally-serpentine cut S (albeit formed of straight-line segments) through panels  90  and  94  may be made so that, when panels  90  and  94  also are severed along edge  98 , four components  101 - 104  are created. Each of components  101  and  104  thus has a generally-convex edge  106 , while each of components  102  and  103  has a complementary generally-concave edge  105 . Hence, although the perimeter of combined components  101  and  104  remains equal to that of combined components  102  and  103 , the surfaces of each combination differ. 
     This difference permits airbag  86  to be curved as shown in  FIGS. 10A-D . To form airbag  86 , (1) components  102  and  103  may be connected along their respective versions of edge  105  (see, e.g.,  FIG. 9C ), (2) components  101  and  104  may be connected along their respective versions of edge  106 , (3) components  101  and  102  may be connected along their respective versions of edge  107 , and (4) components  103  and  104  may be connected along their respective versions of edge  108 . As with other connections described herein, any appropriate connection method may be utilized. Preferably, though, such connections result from sewing, bonding, or welding. Similarly, such connections may occur in any appropriate order or sequence. Finally, because of the shapes and structures of components  101 - 104 , assembly of airbag  86  may occur edge-to-edge and with components  101 - 104  flat. 
     As curved, airbag  86  presents a somewhat concave face  109  to dashboard D when deployed and a somewhat convex face  110  to a vehicle occupant (see  FIGS. 10B-C ). Face  109  clearly accommodates, if not complements, the somewhat convex shape of dashboard D. Face  110  presents a satisfactory surface for contact by the occupant during a crash. (Alternatively, airbag  86  may deploy as illustrated in  FIG. 10D , for example.) As depicted in  FIG. 10C , airbag  86  may be especially useful for protecting knees of occupants. 
       FIGS. 11A-B  detail alternate panels  90 A and  90 B which may be cut from linear strip  10 D of material  14 . Each panel  90  and  90 B includes an edge  105  cut in multiple straight segments to form a generally-concave shape and a straight edge  106  whose segments form a generally-convex shape. Appropriate edges of panels  90 A and  90 B may be joined to create airbag  86 . Alternatively, airbag  86  may be formed of components having curved edges using methods including (but not limited to) sewing, bonding, or welding. 
     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention.