Abstract:
A cushion for protecting a vehicle occupant&#39;s head. The cushion inflates and deploys smoothly and is configured so that gas leakage out of the cushion is reduced in order to maintain the inner pressure high for an extended period of time. The cushion includes a protective cushion element and outer shell fabrics superposed on both outer surfaces of the protective cushion element. The cushion element includes a cabin-side base fabric and a window-side base fabric that are sewn together by sewing yarns after being bonded to each other by adhesive. The outer shell fabrics are bonded to the protective cushion element by adhesives. When the protective cushion element is inflated, the outer shell fabrics are tightly stretched over the outer surfaces of the inflated protective cushion element so as to cover a depressed portions of the base fabrics.

Description:
BACKGROUND  
         [0001]    The present invention relates to a protective cushion for protection of a vehicle occupant&#39;s head. More particularly, the present invention relates to a cushion which is folded and disposed along an upper corner of a side of a vehicle cabin in the normal state and is inflated into a curtain shape to expand over windows of side doors and a B-pillar in the event of a side impact collision or roll-over of the vehicle.  
           [0002]    One embodiment of a protective cushion for protection of occupant&#39;s head, is a curtain airbag which is folded and disposed along an upper corner of a side of a vehicle cabin in the normal state (i.e., when a vehicle is not in the emergency situation such as the event of a vehicle collision). The airbag inflates into a curtain shape to expand over windows of side doors and a B-pillar in the event of a side impact collision or roll-over of a vehicle. The protective cushion may include two base fabrics which are joined together along their peripheries at a line-shaped joint by stitches of sewing yarns to form a chamber between the base fabrics. The chamber is designed to be filled with gas.  
           [0003]    FIGS.  6 ( a )- 6 ( c ) disclose an exemplary protective cushion or side airbag for protection of a vehicle occupant&#39;s head. FIG. 6( a ) is a front view of a protective cushion  1  for protection of vehicle occupant&#39;s head. FIG. 6( b ) is a sectional view taken along a B-B line of FIG. 6( a ), and FIG. 6( c ) is a sectional view taken along a C-C line of FIG. 6( a ).  
           [0004]    As shown in FIG. 6( b ), the protective cushion  1  includes a cabin-side (i.e. passenger side) base fabric  2  and a window-side base fabric  3  which are superposed and sewn to each other so as to form a chamber  4  between the base fabrics  2  and  3 .  
           [0005]    The base fabrics  2 ,  3  are joined to each other along a joint  10  extending around the peripheries of the fabrics. As shown in FIG. 6( a ), the joint  10  may extend inward from the edge of the fabric. The curtain may also include joints  11 ,  12  for subdividing the chamber  4 , and circular joints  13  for reinforcing areas around ends of the line-shaped joints  11 ,  12 . Each of the circular joints  13  may include a circular opening  14  formed at the center thereof by cutting out the base fabrics  2 ,  3 .  
           [0006]    The cushion  1  extends along the side of the vehicle cabin in the longitudinal direction of the vehicle. The cushion  1  is provided at the front end and the rear end in the longitudinal direction thereof with projecting portions  16 ,  18  which are formed with holes  17 ,  19  to facilitate installation of the cushion to the vehicle body. The cushion  1  is provided along the upper edge thereof with a plurality of projections  20  which are also formed with holes  21  to facilitate connection of the cushion  1  to the vehicle body.  
           [0007]    A gas inlet  5  through which gas from an inflator (not shown) is introduced is formed at the front end or the rear end (see FIG. 6( a )) of the cushion  1 . It should be understood that the position of the gas inlet  5  is not limited thereto and the inflator may be disposed inside the cushion.  
           [0008]    The line-shaped joint  11  is apart from the line-shaped joint  10  extending along the cushion. Each end of the line-shaped joint  11  are respectively connected to the circular joints  13 .  
           [0009]    The upper and lower ends of the line-shaped joint  12  both are apart from the line-shaped joint  10  extending along the upper edge and the lower edge of the cushion and both are connected to the circular joints  13 , respectively. The line-shaped joints  11 ,  12  limit the thickness of the inflated chamber  4 . The circular joints  13  reinforce the ends of the line-shaped joints  11 ,  12 .  
           [0010]    The cushion  1  may be installed so that the projecting portion  16  at the front end is fixed to an A-pillar of the vehicle by bolts or rivets through the holes  17  thereof. The projecting portion  18  at the rear end may be fixed to a C-pillar by a bolt or rivet through the hole  19  thereof, and the projections  20  along the upper edge may be fixed to a roof side rail by bolts or rivets through the holes  21  thereof. Prior to deployment, the cushion  1  is stored in a folded condition along the upper corner of the vehicle side surface along the roof side rail. The folded cushion  1  may be covered by a cover (not shown). The cover is adapted to be torn or opened when the cushion  1  is inflated.  
           [0011]    When the vehicle suffers a side impact collision or roll-over, the inflator (not shown) is actuated, gas flows into the chamber  4  through the gas inlet  5  so that the cushion  1  is inflated and deployed downwardly along the side surface of the vehicle cabin into the curtain shape, thereby protecting the head of occupant.  
           [0012]    It is preferable to maintain the head protecting cushion in the inflated state for a period of time (at least several seconds) after inflation not only for prevention of collision of the occupant&#39;s head to the window glass or the B-pillar at the instant of the side impact collision of the vehicle but also for protection of the occupant just after the roll-over of the vehicle.  
           [0013]    The protective cushion is inflated in a relatively narrow space between the occupant&#39;s head and the window glass or the B-pillar in the event of a side impact collision of the vehicle. Accordingly, it is necessary to reduce the thickness of the protective cushion when inflated. As a result, the cabin-side base fabric  2  and the window-side base fabric  3  are connected by line-shaped joints  11 ,  12  and circular joints  13  in addition to the peripheral connecting seam  10 .  
           [0014]    As the cushion  1  is inflated, depressed portions C recessed from the outer surfaces of the inflated cushion  1  are created near the joints  11 ,  12 ,  13 , as shown in FIG. 6( c ). Conventional airbags lack a covering for the depressed portions, thus, creating an uneven surface that contacts the occupants head. As a result, the surface area of the cushion that contacts the occupant and/or the vehicle is reduced and the amount of energy absorbed by the cushion is also reduced.  
         SUMMARY OF THE INVENTION  
         [0015]    According to an embodiment of the present invention a cushion for protection of vehicle occupant&#39;s head is provided. The cushion is fixed at its upper portion to a portion near the corner between a ceiling and a side surface of a vehicle cabin and is inflated downwardly along the side surface by gas and comprises a cabin-side base fabric and a window-side base fabric which are connected to form an envelope shape. The protective cushion is configured so that the cabin-side base fabric and the window-side base fabric are joined at least one joint portion besides the joint portion along the periphery of the protective cushion, whereby at least one depressed portion is created at and around the joint portion when the protective cushion is inflated. The cushion includes an outer shell fabric for covering said depressed portion which is superposed on at least the outer surface of the cabin-side base fabric, said outer shell fabric being joined to the protective cushion.  
           [0016]    According to the aforementioned embodiment of the present invention, the outer shell fabric covers the depressed portion. Therefore, the amount of energy absorbed by the cushion when the occupant&#39;s head comes in collision with a portion at or around the depressed portion increases from the amount of energy absorbed by a protective cushion without a covering for the depressed portion.  
           [0017]    The outer shell fabric may be arranged on the cabin-side only and/or may include fabric covering the window-side too. When the outer shell fabrics are arranged on both sides, the energy absorbing amount is further increased. In addition, the protective cushion is easily inflated into a symmetrical configuration relative to the cabin-side and the window-side.  
           [0018]    In the present invention, the outer shell fabric(s) is preferably joined to the protective cushion at portions along a pair of opposite sides. This is because the joint portions of the outer shell fabric to the protective cushion are easy to increase the volume of the protective cushion in the folded state. By reducing the number and volume of the joint portion between the outer shell fabric and the protective cushion as smaller as possible, the volume of the protective cushion in the folded state can be reduced.  
           [0019]    Alternatively, by shifting the joint portions between said cabin-side base fabric and said window-side base fabric from the joint portions of the outer shell fabric(s) relative to the protective cushion, the volume of the protective cushion in the folded state can be reduced.  
           [0020]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    These and other features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.  
         [0022]    [0022]FIG. 1( a ) is a side view of a cushion for protection of vehicle occupant&#39;s head according to an embodiment.  
         [0023]    [0023]FIG. 1( b ) is an exploded perspective view of the embodiment of FIG. 1( a ).  
         [0024]    [0024]FIG. 1( c ) is a sectional view taken along a line C-C of FIG. 1( b ).  
         [0025]    FIGS.  2 ( a ),  2 ( b ) are sectional views taken along a line II-II of FIG. 1( b ), wherein FIG. 2( a ) shows the non-inflated state and FIG. 2( b ) shows the inflated state.  
         [0026]    FIGS.  3 ( a ),  3 ( b ) are sectional views taken along a line III-III of FIG. 1 ( b ), wherein FIG. 3( a ) shows the non-inflated state and FIG. 3( b ) shows the inflated state.  
         [0027]    [0027]FIG. 4 is a side view of a protective cushion according to another embodiment of the present invention.  
         [0028]    [0028]FIG. 5( a ) is an exploded perspective view of a cushion according to another embodiment of the present invention, FIG. 5( b ) is a view of the fabric panels of the cushion shown in FIG. 5( a ).  
         [0029]    [0029]FIG. 6( a ) is a front view of a cushion for protection of vehicle occupant&#39;s head according to a conventional example, FIG. 6( b ) is a sectional view taken along a B-B line of FIG. 6( a ) FIG. 6( c ) is a sectional view taken along a C-C line of FIG. 6( a ). 
     
    
     DETAILED DESCRIPTION  
       [0030]    Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. FIG. 1( a ) discloses a protective cushion  30  for protection of vehicle occupant&#39;s head according to an embodiment of the present invention. The cushion includes a protective cushion element  31 , and outer shell fabrics  51 ,  52  superposed on the both side surfaces of the protective cushion element  31 , as shown in FIG. 1( b ).  
         [0031]    Also in this exemplary embodiment of the present invention, the protective cushion element  31  comprises a cabin-side base fabric  32  and a window-side base fabric  33  which are sewn to each other by sewing yarns in order to form a chamber  34  between the base fabrics  32  and  33 . The base fabrics  32 ,  33  are joined to each other by joints or seams formed with sewing yarns including a line-shaped joint  40  extending around the peripheries of the base fabrics (with some parts thereof extending inward of the base fabrics  32 ,  33 ), line-shaped joints  41 ,  42 ,  43 ,  44  for subdividing the chamber  34  and for restraining the thickness of the cushion by a predetermined amount, and circular joints  45  for reinforcing areas around ends of the line-shaped joints  41 - 44 .  
         [0032]    According to this embodiment of the present invention, the cabin-side base fabric  32  and the window-side base fabric  33  are bonded to each other by adhesive  39 . Following the bonding with adhesive, the fabrics are sewn together by sewing yarns.  
         [0033]    The protective cushion element  31  is provided at the rear end thereof with a gas inlet  35  for introduction of gas from an inflator (not shown). The protective cushion element  31  is provided along the upper edge thereof with a plurality of projections  36  for installation of the protective cushion  30  to a vehicle body such as a roof side rail. The projections  36  are formed with holes for insertion of bolts, respectively. The protective cushion element  31  is provided at the front end thereof with holes  37  for installation to an A-pillar.  
         [0034]    The outer shell fabrics  51 ,  52  may have a rectangular shape different from the shape of the cabin-side base fabric  32  and the window-side base fabric  33  as main parts. The shape of the outer shell fabrics  51 ,  52  may include any shape in which the outer shell fabric is capable of substantially entirely covering depressed portions C (which are described further below). The outer shell fabrics  51 ,  52  may be made of the same fabric of the protective cushion element  31  and are preferably made of relatively thin fabric of, for example, 70-210 deniers in order to reduce the volume of the folded cushion as smaller as possible.  
         [0035]    The outer shell fabrics  51 ,  52  may be bonded to the protective cushion element  31  by adhesives  55 . In the exemplary embodiment of the present invention shown in FIGS.  1 ( a )- 1 ( c ), the adhesives  55  are applied to the outer surfaces of the protective cushion element  31  into a narrow band shape along the line-shaped joint  40  at the front end and the rear end of the cushion. The adhesives  55  are shifted from the position of the line-shaped joint  40 . In this embodiment, the adhesives  55  are located on the outside of the line-shaped joint  40  of the protective cushion element  31 .  
         [0036]    The protective cushion  30  for protection of vehicle occupant&#39;s head is fixed to the vehicle body in the folded state by the holes of the projections  36  and the hole  37  at the front end. The protective cushion  30  for protection of vehicle occupant&#39;s head is covered by a cover (not shown). The cover is adapted to be torn or opened when the protective cushion  30  is inflated. The cover may be a roof garnish or decoration for the vehicle.  
         [0037]    When the vehicle suffers a side impact collision or roll-over, the inflator is actuated, gas flows into the chamber  34  through the gas inlet  35  so that the cushion  30  is inflated and deployed downwardly along the side surface of the vehicle cabin, thereby protecting the head of the occupant. During the deployment of the cushion or side airbag, since the line-shaped joints  40 - 44  and circular joints  45  join the cabin-side base fabric  32  and the window-side base fabric  33 , the thickness of portions around the joints  40 - 44  and  45  of the protective cushion element  31  is smaller than that of the other portions.  
         [0038]    Accordingly, depressed portions C (C 1 , C 2 , C 3 ) recessed from the outer surfaces of the protective cushion  31  are created at and around the joints  40 - 44  and  45 . The outer shall fabrics  51 ,  52  cover the depressed portions C. Since the outer shell fabrics  51 ,  52  are bonded at their ends to the protective cushion element  31  by the adhesives  55 , the outer shell fabrics  51 ,  52  are tightly stretched over the outer surfaces of the inflated protective cushion element  31  so that the depressed portions C are covered by the outer shell fabrics  51 ,  52  just like lids. Therefore, when the occupant&#39;s head plunges into the cushion toward the depressed portion C, the occupant&#39;s head can be received by the outer shell fabrics  51 ,  52 . As a result, the impact of the occupant&#39;s head can be absorbed by a region including the depressed portion C and the outer shell fabric covering the depressed portion C, thereby increasing the absorbing amount.  
         [0039]    In this embodiment, the inflated protective cushion element  31  is prevented from being damaged by fragments of window glasses because the inflatable portion of the cushion element  31  is entirely shielded by the outer shell fabrics  51 ,  52 .  
         [0040]    Though the adhesives  55  are only applied to the portions at the both ends in the longitudinal direction of the protective cushion element  31  in the aforementioned embodiment, the adhesives  55  may also be applied to portions along the upper and lower edges of the protective cushion element, as shown in the alternative embodiment of the present invention disclosed in FIG. 4, in order to join the protective cushion element  31  and the outer shell fabrics  51 ,  52  at these portions. Further, the adhesives  55  may be applied to the entire periphery of the protective cushion element. The application of the adhesives  55  increases the volume of the protective cushion when folded. Therefore, it is preferable to apply the adhesives  55  only at the both ends or along the upper and lower edges of the cushion.  
         [0041]    In order to reduce the volume of the cushion when folded, the adhesives  55  and the adhesive  39  are preferably arranged not to superposed on each other like the illustrated embodiment.  
         [0042]    Though the outer shell fabrics  51 ,  52  are separated pieces in the aforementioned embodiment, the outer shell fabrics may be outer shell fabrics  51 A,  52 A composed of one continuous piece as shown in FIGS.  5 ( a ),  5 ( b ). The piece for the outer shell fabrics  51 A,  52 A is folded double along the center line L and is superposed on and bonded to the protective cushion element  31  by the adhesive as shown in FIG. 5( a ).  
         [0043]    Though the adhesives  55  are applied to be positioned on the outside of the line-shaped joint  40  in the aforementioned embodiments, the adhesives  55  may also or alternatively be positioned on the inside of the line-shaped joint  40  of the protective cushion element  31 .  
         [0044]    Though the outer shell fabrics  51 ,  52  are arranged on both the cabin-side and window-side of the protective cushion element  31  in the aforementioned embodiments, the outer shell fabric  51  may be arranged on the cabin-side only. According to this arrangement, there is possibility that the protective cushion  30  warps toward the inside of the cabin when the protective cushion  30  is inflated. Therefore, it is preferable that the outer shell fabrics  51 ,  52  are arranged on both sides. As the outer shell fabrics  51 ,  52  are arranged on both sides, the protective cushion  30  never warps and is inflated into a symmetrical configuration relative to the cabin-side and the window-side.  
         [0045]    The protective cushion element and the outer shell fabrics may be fixed by sewing instead of adhesive. In this case, the outer shell fabrics may be sewn to the protective cushion element at the same time as sewing the outer periphery of the protective cushion element, thereby reducing the number of manufacturing steps.  
         [0046]    It should be understood that the present invention is not limited to the illustrated embodiments and may take another configuration than the illustrated ones.  
         [0047]    As described above, the present invention can provide a protective cushion for head protection which can be sufficiently absorb the impact even with portions at/around the depressed portions of the protective cushion element.  
         [0048]    The priority application, Japanese Patent Application No. 2001-272128 filed Sep. 7, 2001, is hereby incorporated by reference herein in its entirety.  
         [0049]    Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. For example, in one embodiment of the present invention the outer shell fabric may only be place on the side of the cushion facing the passenger. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is to be defined as set forth in the following claims.