Patent Publication Number: US-2007102912-A1

Title: Vehicle occupant protection apparatus having a plastic fill tube

Description:
TECHNICAL FIELD  
      The present invention relates to an inflatable vehicle occupant protection apparatus. More particularly, the present invention relates to an inflatable vehicle occupant protection apparatus having a plastic fill tube.  
     BACKGROUND OF THE INVENTION  
      It is known to inflate an inflatable vehicle occupant protection device to help protect a vehicle occupant. One particular type of inflatable vehicle occupant protection device is an inflatable curtain. An inflatable curtain is inflatable away from the roof of the vehicle and into a position between a vehicle occupant and the side structure of the vehicle.  
      It is also known to use a fill tube to direct inflation fluid from an inflator to an inflatable curtain. A fill tube typically is an elongated, rigid conduit having a first end that is connected to a fluid outlet of the inflator and an opposite second end that is located in the inflatable curtain. Inflation fluid exiting the inflator passes through the fill tube and enters the inflatable curtain for inflating the inflatable curtain.  
      It is common for a fill tube to be manufactured at one location and shipped to another location for assembly into an inflatable vehicle occupant protection apparatus. Due to the elongated and rigid configuration of the fill tube, non-standard and thus more expensive shipping container may be required for the fill tubes. A fill tube that may be shipped using a standard, less expensive shipping container is desired.  
     SUMMARY OF THE INVENTION  
      The present invention relates to a vehicle occupant protection apparatus comprising an inflatable occupant protection device and an inflation fluid source that is actuatable to provide inflation fluid for inflating the inflatable occupant protection device. The vehicle occupant protection apparatus also includes a conduit for directing a flow of inflation fluid from the inflation fluid source into the inflatable occupant protection device. The conduit is formed from a flexible plastic material. The flexible plastic material enables the conduit to be folded.  
      In accordance with another aspect, the present invention relates to a vehicle occupant protection apparatus comprising an inflatable occupant protection device and an inflation fluid source that is actuatable to provide inflation fluid for inflating the inflatable occupant protection device. The vehicle occupant protection apparatus also comprises a conduit for directing a flow of inflation fluid from the inflation fluid source into the inflatable occupant protection device. The conduit is formed from a flexible plastic material and has a deflated condition in which the conduit is substantially flat and an inflated condition in which the conduit has a predetermined shape. The conduit expands from the deflated condition to the inflated condition in response to receiving inflation fluid from the inflation fluid source. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The foregoing and other features of the present invention. will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which:  
       FIG. 1  illustrates a vehicle occupant protection apparatus constructed in accordance with the present invention;  
       FIG. 2  illustrates a portion of a fill tube of the vehicle occupant protection apparatus of  FIG. 1 , in a deflated condition;  
       FIG. 3  is a view taken along line  3 - 3  in  FIG. 2 ;  
       FIG. 4  illustrates a portion of a fill tube of the vehicle occupant protection apparatus of  FIG. 1 , in an inflated condition;  
       FIG. 5  is a view taken along line  5 - 5  in  FIG. 4 ;  
       FIG. 6  is a top view of a portion of the fill tube of the vehicle occupant protection apparatus of  FIG. 1 , in a deflated and partially folded condition; and  
       FIG. 7  is a schematic side view of a portion of the fill tube of the vehicle occupant protection apparatus of  FIG. 1 , in a deflated and folded condition. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  illustrates a vehicle occupant protection apparatus  10  constructed in accordance with the present invention. The vehicle occupant protection apparatus  10  includes an inflator  12  and an inflatable occupant protection device  14 .  
      The inflator  12  is actuatable for providing inflation fluid for use in inflating the inflatable occupant protection device  14 . The inflator  12  may include a stored quantity of pressurized inflation fluid and an ignitable material for heating the inflation fluid. Alternatively, the inflator  12  may include a combustible gas generating material, a stored quantity of pressurized inflation fluid, or any other source for providing inflation fluid.  
      The inflatable occupant protection device  14  of  FIG. 1  is an inflatable curtain. Alternatively, the inflatable occupant protection device  14  may include an inflatable air bag, an inflatable seat belt, an inflatable knee bolster, an inflatable headliner, or a knee bolster operated by an inflatable air bag. The inflatable curtain  14  is preferably made from a flexible fabric material, such as woven nylon.  
       FIG. 1  illustrates the inflatable curtain  14  in a deflated and stored condition. In the deflated and stored condition, the inflatable curtain  14  is folded and stored within a housing  16 . The inflatable curtain  14 , in the deflated and stored condition, and the housing  16  have elongated configurations.  
      The housing  16  is made from a flexible fabric material. Tear seams (not shown) are formed in the housing  16 . The tear seams are designed to tear during inflation of the inflatable curtain  14  to enable the inflatable curtain to exit the housing  16 . The housing  16  is mounted to a vehicle  18  in a location adjacent both the side structure of the vehicle and a roof  20  of the vehicle. The side structure of the vehicle  18  illustrated in  FIG. 1  includes an A-pillar  22 , a B-pillar  24 , a C-pillar  26 , and side windows  28  and  30 .  FIG. 1  shows four mounting brackets  32  for securing the housing  16  to the side structure of the vehicle  18 .  
      The vehicle occupant protection apparatus  10  also includes a fill tube  34  that forms an inflation fluid conduit between the inflator  12  and the inflatable curtain  14 . The fill tube  34  extends from an outlet of the inflator  12  and into the inflatable curtain  14 . In the embodiment illustrated in  FIG. 1 , the fill tube  34  has a length that is approximately equal to the length of the inflatable curtain  14 . Also, in the embodiment illustrated in  FIG. 1 , the fill tube  34  extends longitudinally through approximately ninety percent of the inflatable curtain  14 .  
      The fill tube  34  is formed from an impervious, flexible plastic material, such as polyvinylchloride sheeting or polyethylene. Alternatively, the fill tube  34  may be formed from a fabric that is coated with a plastic material, such as polyvinylchloride sheeting or polyethylene. As is best shown in  FIG. 5 , the fill tube  34  has a generally cylindrical wall portion  38  that is centered on an axis A. The wall portion  38  includes inner and outer surfaces  40  and  42 , respectively. The inner surface  40  of the wall portion  38  defines an interior space  44  of the fill tube  34 . Multiple through-holes  46  ( FIG. 4 ) extend through the wall portion  38 .  
      The fill tube  34  has a deflated condition and an inflated condition.  FIG. 2  illustrates a portion of the fill tube  34  in the deflated condition.  FIG. 4  illustrates the same portion of the fill tube  34  in an inflated condition.  
      The fill tube  34  will assume the deflated condition when the fluid pressure within the interior space  44  and acting on the inner surface  40  of the wall portion  38  is less than the pressure acting on the outer surface  42  of the wall portion. The higher pressure acting on the outer surface  42  of the wall portion  38  forces fluid out of the interior space  44  through the through-holes  46 . As the fluid is forced out of the interior space  44 , the fill tube  34  flattens. When the fill tube  34  flattens, the inner surface  40  of the wall portion  38  collapses on itself so that a first half of the inner surface overlies a second half of the inner surface, as is shown in  FIG. 3 . The fill tube  34 , when in the deflated condition, has the generally flat configuration shown in  FIGS. 2 and 3 . Also, when the fill tube  34  is in the deflated condition, the volume of the interior space  44  is substantially eliminated.  
      As shown in  FIG. 3 , when the fill tube  34  is in the deflated condition, the fill tube  34  includes lower and upper surfaces  52  and  54 , respectively. The fill tube  34 , when in the deflated condition, may be folded upon itself, as is illustrated with reference to  FIGS. 6 and 7 .  
       FIG. 6  illustrates a portion of the fill tube  34  in a deflated and partially folded condition. In  FIG. 6 , the portion of the fill tube  34  is being folded in a longitudinal direction to form two adjacent Z-folds  56  and  58  ( FIG. 7 ), respectively. To form the Z-folds  56  and  58 , the deflated fill tube  34  is folded along a first fold line  62  so that a first portion of the upper surface  54  overlies an adjacent, second portion of the upper surface  54 . The deflated fill tube  34  is then folded along a second fold line  64  so that a first portion of the lower surface  52  overlies an adjacent, second portion of the upper surface  52 . Each Z-fold  56  and  58  results in a stack that includes a lower layer  66 , an intermediate layer  68 , and an upper layer  70 . The lower, intermediate, and upper layers  66 ,  68 , and  70  are each formed from adjacent portions of the deflated fill tube  34 .  
      The deflated fill tube  34  may also be rolled or compacted in another matter, other than by folding. When compacted, such as by folding, the deflated fill tube  34  may be shipped using a standard shipping container that has a cost lower than those generally required for fill tubes that may not be compacted.  
      The fill tube  34  is assembled into the vehicle occupant protection apparatus  10  in an unfolded and deflated condition. The fill tube  34  remains in the deflated condition until the inflator of the vehicle occupant protection apparatus  10  is actuated and inflation fluid enters the interior space  44 . Inflation fluid entering the interior space  44  results in increased pressure acting on the inner surface  40  of the wall portion  38 . When the pressure acting on the inner surface  40  of the wall portion  38  becomes greater than the pressure acting on the outer surface  42  of the wall portion, the fill tube  34  expands into the inflated condition, shown in  FIGS. 4 and 5 .  
      When the fill tube  34  is in the inflated condition, the volume of the interior space  44  reaches substantially the maximum volume possible, based on the original cross-sectional shape of the fill tube. The fill tube  34  forms a conduit between the inflator  12  and the inflatable curtain  14 . Inflation fluid exiting the inflator  12  passes through the interior space  44  of the fill tube  34 . The inflation fluid then exits the fill tube  34  via the through-holes  46  and enters the inflatable curtain  14 . The inflatable curtain  14 , in response to receiving the inflation fluid, inflates to cover some or all of the side structures  22 ,  24 ,  26 ,  28 , and  30  of the vehicle  18 .  
      From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.