Abstract:
A curtain airbag assembly for occupant protection in a motor vehicle includes a forward airbag stored above a forward window for deployment to a position wherein a main body portion overlies a forward window and a rear end portion extending rearward from the main body overlies a post separating the windows, such as a B-post or C-post, and a rear airbag stored above a rear window for deployment to a position wherein a main body portion overlies the rear window and a forward end portion extends rearward from the main body and overlies the post. The forward and rear end portions vertically overlap one another where they overlie the post, and each has an end lip defining a recess in an outer face of the respective airbag, the end lips shaped to engage with the post.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims foreign priority benefits under 35 U.S.C. §119(a)-(d) to GB 1020635.7, filed Dec. 6, 2010, which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     This invention relates to curtain airbag assemblies for occupant protection in motor vehicles. 
     BACKGROUND 
     It is well known to provide a motor vehicle with a curtain airbag to protect occupants of the motor vehicle from contact with interior components of the motor vehicle during a crash or other accident, and to prevent a body part of an occupant from passing through a window aperture covered by the curtain airbag. 
     It is further known to provide two airbags arranged in a front-to-rear relationship such that a rear edge of the forward airbag and a forward edge of the rear airbag are connected by one or more tethers. 
     During most crashes, it is generally desirable to ensure that the two adjacent edges of the airbags remain close together throughout the event. Keeping the adjacent edges of the two airbags close together makes it unlikely that a gap will form between the airbags that may permit a portion of the occupant&#39;s body to contact the underlying structure of the motor vehicle, such as a B-post or C-post separating the window openings. Keeping the adjacent edges of the bags together also makes it less likely that any portions of the airbags will be forced through a window opening during a crash. 
     SUMMARY 
     According to a disclosed embodiment, a curtain airbag assembly for a motor vehicle comprises a forward airbag having a main body portion and a rear end portion extending rearward from the main body portion, and a rear airbag having a main body portion and a forward end portion extending forward from the main body portion. The rear end portion and the forward end portion vertically overlap with one another. The forward and rear end portions each have an end lip defining a recess in an outer face of the respective airbag, the end lips shaped to engage with a structural member of the vehicle that the end portions overlie in their zone of vertical overlap. 
     According to another disclosed embodiment, a motor vehicle comprises a post separating a forward window opening and a rear window opening, and an airbag assembly that includes a forward airbag and a rear airbag. The forward airbag is stored in an uninflated condition above the forward window for deployment downward to an inflated condition wherein a main body portion overlies at least a portion of the forward window and a rear end portion extends rearward from the main body portion and overlies the post. The rear airbag stored is in an uninflated condition above the rear window for deployment downward to an inflated condition wherein a main body portion overlies at least a portion of the rear window and a forward end portion extends rearward from the main body portion and overlies the post. The forward end portion and the rear end portion vertically overlap one another at the locations where they overlie the post. 
     According to another disclosed embodiment, the forward and rear end portions each have an end lip defining a recess in an outer face of the respective airbag, the recesses shaped to engage with the post. 
     According to another disclosed embodiment, the motor vehicle further comprises a second post separating the rear window opening from a third window opening rearward of the rear window opening, and a third airbag is stored in an uninflated condition above the third window. The third airbag deploys downward to an inflated condition wherein a main body portion overlies at least a portion of the third window and a forward end portion extends forward from the main body portion and overlies the second post. The rear airbag further has a rear end portion extending rearward from the main body portion to overlie the second post, such that the forward end portion of the third airbag vertically overlaps with the rear end portion of the rear airbag at the second post. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described by way of example with reference to the accompanying drawing of which: 
         FIG. 1  is a partial interior side view of a right hand side of a motor vehicle having a curtain airbag assembly showing two airbags in a stowed state before deployment; 
         FIG. 2  is a view similar to that of  FIG. 1  but showing the two airbags in a deployed state; 
         FIG. 3  is a cross-section along the line Y-Y on  FIG. 2 ; 
         FIG. 4  is a cross-section along the line X-X on  FIG. 2 ; 
         FIG. 5  is a view similar to that shown in  FIG. 2  but showing a second embodiment of an airbag assembly; and 
         FIG. 6  is a cross-section along the line Z-Z on  FIG. 5   
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     With particular reference to  FIGS. 1 to 4  there is shown a motor vehicle  5  having a body structure  6  including a side wall  6 W. The side wall  6 W defines four window apertures  7 A,  7 B,  7 C and  7 D. The first window aperture  7 A is separated from the second window aperture  7 B by a first generally vertical structural member in the form of a B-post  8 B, the second window aperture  7 B is separated from the third window aperture  7 C by a second vertically extending structural member in the form of a C-post  8 C, and the third window aperture  7 C is separated from the fourth window aperture  7 D by a third vertically extending structural member in the form of a D-post. It will be appreciated that the body structure  6  also includes an A-post (not shown) located forwardly of the B-post  8 B and an E-post (not shown) located to the rear of the D-post  8 D. The term “generally vertical,” as used herein, describes a structural member extending between a roof and/or other portion of the motor vehicle above (and/or defining the upper edge of) a window opening and a portion of the motor vehicle below (and/or defining the lower edge of) a window opening. 
     The front of the motor vehicle  5  is indicated by the arrow F on  FIG. 1   
     Two storage compartments  9 A and  9 B are formed as part of or attached to the body structure  6  to house two airbags  20 ,  30  in their uninflated conditions prior to deployment, as is well known in the art. 
     The airbag assembly comprises four airbags  10 ,  20 ,  30  and  40  arranged in a front-to-rear relationship along the length of motor vehicle  5 . A first airbag  10  has a front edge adjacent to or overlying the A-post of the motor vehicle  5  and a rear end portion overlying the B-post  8 B of the motor vehicle  5 ; a second airbag  20  has a front end portion overlying the B-post  8 B and a rear end portion overlying the C-post  8 C of the motor vehicle  5 ; a third airbag  30  has a front end portion overlying the C-post  8 C and a rear end portion overlying the D-post  8 D of the motor vehicle  5 ; and a fourth airbag  40  has a front end portion overlying the D-post  8 D and a rear edge adjacent to or overlying the E-post of the motor vehicle  5 . 
     The front end portion of each adjacent airbag complements the rear end portion of the respective adjacent airbag so that a part of both end portions can overlie a respective common structural member  8 B,  8 C,  8 D. 
     Each of the end portions of the airbags  10 ,  20 ,  30  and  40  includes a tongue  11 ,  22 ,  23 ,  32 ,  33 ,  43  extending forwardly or rearwardly away from a main body of the respective airbag  10 ,  20 ,  30 ,  40  so as to overlie the respective structural member  8 B,  8 C and  8 D. Each of the tongues  11 ,  22 ,  23 ,  32 ,  33 ,  43  may extend past the respective structural member to overlie a portion of the adjacent window aperture  7 A,  7 B,  7 C and  7 D. The tongues comprising each pair  11 ,  23 ;  22 ,  33 ; and  32 ,  43  overlap one another vertically. 
     Although in  FIGS. 2 and 4  a gap is shown between adjacent airbags, this is purely for illustrative purposes and in practice adjacent airbags  10 ,  20 ;  20 ,  30  and  30 ,  40  may abut against one another. 
     The first airbag  10  has an L-shaped rear end portion formed by a rear end wall  18  and the lower tongue  11  extending rearward past the rear end wall. Although not shown in the figures, an outer face of the tongue  11  is shaped so as to be engageable, when the airbag  10  is deployed, with the B-post  8 B. A front portion (not shown) of the first airbag  10  may be shaped for cooperation with the A-post. 
     The second airbag  20  has an inverted L-shaped front end portion formed by a front end wall  27  and the upper tongue  23  extending forward past the front end wall. Second airbag  20  further has an L-shaped rear end portion formed by a rear end wall  28  and the lower tongue  22  extending rearward past the rear end wall. An outer face (facing outward from the vehicle cabin to face the side wall  6 W) of the tongue  23  includes an end lip  25  defining a recess  26 B shaped and located to engage, when the airbag  20  is deployed, with the B-post  8 B. An outer face of the tongue  22  includes an end lip (not shown) defining a recess shaped and located to engage, when the airbag  20  is deployed, with the C-post  8 C. This engagement of the airbag  20  with the B and C posts  8 B and  8 C prevents sliding of the airbag  20  in a longitudinal direction of the motor vehicle  5 . 
     As the second airbag  20  has an inverted L-shaped front end portion and an L-shaped rear end portion, the configuration of second airbag as a whole may be said to be “Z-shaped,” as is apparent from  FIG. 2 . 
     The tongue  11  on the first airbag  10  is located near to a lower edge of the airbag  10  and the tongue  23  on the second airbag  20  is located near to an upper edge  24  of the second airbag  20  so that the two tongues  11 ,  23  can nest or interlock with one another, in an over-under relationship. 
     It will be appreciated that when the first and second airbags  10  and  20  are in their fully deployed states a friction force is generated between the two tongues  11 ,  23  particularly along a horizontal interface formed between the two tongues  11 ,  23 . This friction force is advantageous in that it resists sliding of one tongue  11  relative to the other  23  thereby holding the two airbags  10 ,  20  together. 
     The third airbag  30  has a inner face FF facing into a passenger compartment of the motor vehicle  5  when the airbag  30  is deployed, an outer face RF facing towards a window glass  7 G located in the window aperture  7 C and is inflatable by means of an inflator  36  located adjacent to a top edge  34  of the airbag  30 . The third airbag  30  has an inverted L-shaped front end portion formed by a front end wall  37  and the upper tongue  33  extending forward past the front end wall. Third airbag  30  further has an L-shaped rear end portion formed by a rear end wall  38  and the lower tongue  32  extending rearward past the rear end wall. An outer face of the tongue  33  includes an end lip  35  defining a recess  26 C shaped and located to engage, when the airbag  20  is deployed, with the C-post  8 C. An outer face of the tongue  32  also has a recess (not visible in  FIG. 4 ) formed in it for cooperation with the D-post  8 D. As before, this engagement with the C and D posts  8 C and  8 D is advantageous in that it prevents sliding of the airbag  30  in a longitudinal direction of the motor vehicle  5 . 
     The tongue  22  on the second airbag  20  is located near to the lower edge of the airbag  20  and the tongue  33  on the third airbag  30  is located near to an upper edge  34  of the third airbag  30  so that the two tongues  22 ,  33  can nest or interlock with one another. 
     It will be appreciated that when the second and third airbags  20  and  30  are in their fully deployed states a friction force is generated between the two tongues  22 ,  33  particularly along a horizontal interface formed between the two tongues  22 ,  33 . This friction force is advantageous in that it resists sliding of one tongue relative to the other thereby holding the two airbags  20 ,  30  together. 
     The fourth airbag  40  has an L-shaped front end portion formed by a front end wall  47  and the tongue  43  and a rear end (not shown). An outer face of the tongue  43  includes an end lip  45  defining a recess  26 D that is engageable, when the airbag  20  is deployed, with the D-post  8 D. As before, the engagement of the tongue  43  with the D-post is advantageous in that it helps to prevent sliding of the airbag  40  in a rearward longitudinal direction of the motor vehicle  5 . 
     The tongue  32  on the third airbag  30  is located near to the lower edge of the airbag  30  and the tongue  43  on the fourth airbag  40  is located near to an upper edge of the fourth airbag  40  so that the two tongues  32 ,  43  can nest or interlock with one another. 
     As before, when the third and fourth airbags  30  and  40  are in their fully deployed states, a friction force is generated between the two tongues  32 ,  43  particularly along a horizontal interface formed between the two tongues  32 ,  43 . This friction force resists sliding of one tongue relative to the other thereby holding the two airbags  30 ,  40  together. 
     Although in the embodiment described the second and third airbags  20  and  30  are “Z-shaped” it will be appreciated that the invention is not limited to such shapes or to the orientation of such a shape and that other combinations of shape could be used. For example the first and fourth airbags could be “L-shaped”, the second and third airbags could be “T-shaped” and the second and third airbags could be inverted relative to one another so that one is wider at the upper edge than the lower edge and vice versa. However, in all cases the shaping of the adjacent airbags is such that the two airbags can overlap or interlock with one another so as to overlie a common structural member, such as a B- or C-post. 
     Referring now to  FIGS. 5 and 6  there is shown a second embodiment of the invention that is particularly applicable to a motor vehicle in the form of a passenger car. 
     The motor vehicle has A, B and C posts  108 A,  108 B and  108 C (shown only as chain dotted outlines on  FIG. 5 ) and two airbags  120 ,  130 . 
     A first airbag  120  covers the A and B posts  108 A and  108 B and a second airbag  130  covers the B and C posts  108 B and  108 C. 
     The first airbag  120  has an L-shaped rear end portion formed by a rear end wall  128  and a tongue  122 . An outer face of the tongue  122  has a lip  125  and is shaped so as to be engageable, when the airbag  120  is deployed, with the B-post  108 B. The first airbag  120  has an inflator  151  located at an upper edge  124  of the airbag  120  for inflating the airbag  120  so as to deploy it. 
     A front portion of the first airbag  120  is defined by a front edge  127  and has a recess  126  shaped to conform with the A-post  108 A. 
     The second airbag  130  has an L-shaped front end portion formed by a front end wall  137  and a tongue  132 . An outer face of the tongue  132  has a lip (not shown) and is shaped so as to be engageable, when the airbag  120  is deployed, with the B-post  108 B. The second airbag  130  has an inflator  152  located at an upper edge  134  of the airbag  120  for inflating the airbag  130  so as to deploy it. 
     A rear portion of the second airbag  130  is defined by a rear edge  138  and has a recess  136  shaped to conform to the C-post  108 C. 
     When the first and second airbags  120  and  130  are in their fully deployed states, a friction force is generated between the two tongues  122 ,  132  particularly along a horizontal interface formed between the two tongues  122 ,  132 . This friction force is advantageous in that it resists sliding of one tongue relative to the other thereby holding the two airbags  120 ,  130  together. 
     The abutting end portions of the first and second airbags  120 ,  130  are L-shaped and the L-shaped portion on the second airbag  130  is inverted relative to the L-shaped portion on the first airbag  120  so that the tongues  122 ,  132  can overlap with one another in the vertical direction. 
     With particular reference to  FIG. 5  it can be seen that when the first and second airbags  120  and  130  are fully deployed the tongue  122  of first airbag  120  is located near to a lower edge of the first airbag  120  and extends rearwardly towards the second airbag  130  so as to fully overlie the B-post  108 B, and further that the tongue  132  of second airbag  130  extends forwardly towards the first airbag  120  so as to fully overlie the B-post  108 B. The two tongues  122 ,  132  lie contact to one another and overlap one another in the vertical direction. Although a gap is shown in  FIG. 5  between the two airbags  120 ,  130  and between the tongues  122 ,  132  this is merely for illustrative purposes and in practice the first and second airbags  120  and  130  may contact or abut one another and the two tongues  122 ,  132  interact with one another. 
     Although it is desirable to form the outer surface of each of the tongues  122 ,  132  so that it can conform to the shape of the underlying structural member (such as the B-post  108 B) it will be appreciated that the length of the tongues  122 ,  132  is such that even if they do not engage with the underlying B-post  108 B the large distance of overlap of the tongues makes results in a low possibility that movement of the two airbags  120 ,  130  in opposite horizontal directions will expose the underlying B-post  108 B. 
     It will be appreciated by those skilled in the art that although the invention has been described by way of example with reference to one or more embodiments it is not limited to the disclosed embodiments and that one or more modifications to the disclosed embodiments or alternative embodiments could be constructed without departing from the scope of the invention as set out in the appended claims. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.