Abstract:
A protecting device for an occupant of a vehicle includes: an airbag positioned to inflate along an interior side of a vehicle; an elongated inflator including a tube extending along the interior side of the vehicle in a longitudinal direction of the vehicle; several openings in the tube positioned to allow inflation gas to enter and inflate the airbag.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to and the benefit of U.S. Provisional Application No. 60/567,653, filed May 4, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to an inflation device for a protective cushion for protection of a vehicle occupant. More particularly, the present invention relates to an inflation device for providing inflation gas for 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.  
         [0003]     Airbag devices mounted in vehicles such as automobiles typically include a gas generator or inflator. The inflator operates to inflate an airbag which is positioned to protect a passenger&#39;s body when the vehicle is involved in an emergency situation such as a collision.  
         [0004]     Characteristics of an airbag are determined to a large extent by the inflator. For example, the location of the inflator may cause portions of the airbag to inflate at different rates. Typically, a portion of the airbag located closest to the inflator will inflate faster than a portion of the airbag located a location remote from the inflator. As a result, after an emergency condition is detected, certain portions of the airbag may require more time to reach an inflated state adequate to protect an occupant of the vehicle.  
         [0005]     Furthermore, passengers sitting near the side of a vehicle are much closer to the point of collision during a side impact than they are in the case of a front impact to the vehicle. Thus, the importance of rapid and complete inflation of the airbag is heightened when the vehicle is involved in a side impact collision.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention aims to solve at least one of these and other problems.  
         [0007]     According to an embodiment of the present invention, a protecting device for an occupant of a vehicle comprises: an airbag positioned to inflate along an interior side of a vehicle; an elongated inflator including a tube extending along the interior side of the vehicle in a longitudinal direction of the vehicle; and a plurality of openings in the tube positioned to allow inflation gas to enter and inflate the airbag, wherein a number of openings per length of the inflator in meters is between about 20 and about 100.  
         [0008]     According to another embodiment of the present invention, a protective device for an occupant of a vehicle comprises: an airbag positioned to inflate along an interior side of a vehicle; and an elongated inflator including a tube extending along the interior side of the vehicle in a longitudinal direction of the vehicle, wherein a ratio of a length of the tube to a length of the airbag is between about 0.7 and about 1.0.  
         [0009]     According to another embodiment of the present invention, a protective device for an occupant of a vehicle comprises: an airbag positioned to inflate along an interior side of a vehicle; an elongated inflator including a tube extending along the interior side of the vehicle in a longitudinal direction of the vehicle; and a plurality of openings in the tube positioned to allow inflation gas to enter and inflate the airbag, wherein a ratio of a cross sectional area of the tube to an area of one of the openings is between about 2 and about 20.  
         [0010]     According to another embodiment of the present invention, a protective device for an occupant of a vehicle comprises: an airbag positioned to inflate along an interior side of a vehicle; an elongated inflator including a tube extending along the interior side of the vehicle in a longitudinal direction of the vehicle; and a plurality of openings in the tube positioned to allow inflation gas to enter and inflate the airbag, wherein a ratio of an area of one of the opening to a length of the tube is between about 0.01 (mm 2 /mm) and about 0.04 (mm 2 /mm).  
         [0011]     According to another embodiment of the present invention, a protective device for an occupant of a vehicle comprises: an airbag positioned to inflate along an interior side of a vehicle; and an elongated inflator including a tube extending along the interior side of the vehicle in one of a longitudinal and a lateral direction of the vehicle, wherein a ratio of a length of the inflator to a length of the vehicle in the one of a longitudinal and a lateral direction is between about 0.6 and 1.0. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     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.  
         [0013]      FIG. 1  is a cross-section side view of an inflator according to an exemplary embodiment of the present invention.  
         [0014]      FIG. 2  is a side view of an occupant protecting device according to an embodiment of the present invention.  
         [0015]      FIG. 3  is a cross-sectional view of a portion of a pipe according to an embodiment of the present invention.  
         [0016]      FIG. 4  is a cross-sectional view of a portion of a pipe according to another embodiment of the present invention.  
         [0017]      FIG. 5  is a cross-sectional side view of a pipe according to an exemplary embodiment of the present invention.  
         [0018]      FIG. 6  is a side view of an inflator and airbag according to an embodiment of the present invention.  
         [0019]      FIG. 7  is a partial side view of an inflator according to an embodiment of the present invention.  
         [0020]      FIG. 8  is a side view of a inflator according to an embodiment of the present invention.  
         [0021]      FIGS. 9   a - 9   c  show cascade inflators connected to an automobile in various configurations. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.  
         [0023]     According to an embodiment of the present invention an inflator is provided. As shown in  FIG. 1 , the inflator includes a pipe  100  having a plurality of openings  110 . The pipe  100  includes an interior chamber  150  that is filled with an inert gas. The inert gas may include, for example, Argon or Helium. The inert gas may be charged into the pipe  100  through gas inlet opening  120 . After the gas is charged into the pipe, the inlet  120  may be sealed, for example, by a ball weld  130 . Thus, prior to initiation, the inflator is filled with a prepressurized gas.  
         [0024]     The pipe  100  includes two ends  140 . Each end  140  of the pipe contains an inflation device  200 . The inflation device  200  includes an igniter or initiator  210  and a booster cap  220 . The cap  220  covers the igniter  210  and contains a booster propellant  230 . Each end  140  of the pipe is sealed by caulking material  145 . The igniter  210  includes a portion that extends out of the pipe  100  and is operatively connected to a control circuit that sends a trigger signal to the igniter when a collision involving the related vehicle is determined to be imminent.  
         [0025]     Prior to initiation of the inflator, each of the openings  110  is sealed. According to one exemplary embodiment of the present invention, the openings  110  are closed by a seal  115 . The seal  115  is configured to rupture or break when the pressure of the inert gas reaches a predetermined level. The seal  115  may include tape or other similar membranes. Alternatively, as shown in  FIG. 3 , the opening  10  may be formed as a partial puncture  113  of the wall of the pipe  100 . For example, the pipe  100  may be formed of stainless material and a punch may be used to partially penetrate the wall of the pipe  100  to create a weakened portion that ruptures when the pressure of the inert gas located in the pipe reaches a predetermined level.  
         [0026]     As mentioned above, the pipe  100  may be formed of stainless steel or other material of sufficient strength to contain the pressurized gas. According to a preferred embodiment of the present invention, the pipe  100  may be bent to conform to the shape of the airbag containing the inflator. However if, for example, the airbag contains a substantially straight upper portion, the pipe  100  may extend along an essentially straight line as shown in  FIG. 4 .  
         [0027]     As shown in  FIG. 2 , the inflator may be positioned inside an airbag  300  for protecting an occupant of a vehicle. In a preferred embodiment of the present invention, the airbag  300  is configured to inflate along the side of a vehicle. As shown in  FIG. 2 , the airbag may extend from the A pillar  410  to cover the B pillar  420 , and reach the C pillar  430 . The airbag  300  may include multiple cells or sections  310 . Each of the inflation gas outflow openings  110  may be aligned with the cells  310 . Furthermore, as shown in  FIG. 2 , the shape of the pipe or tube  100  may be curved to conform to the shape of the upper portion of the airbag  300 .  
         [0028]     In operation, the initiator  210  is triggered by a signal generated by a sensor (e.g., an acceleration type crash sensor) in response to the sensor detecting that a collision involving the vehicle is imminent. After triggering of the initiator  210 , the booster propellant  230  ignites creating exhaust gas that ruptures the cap  220  and raises the pressure of the inert gas contained within the pipe  100 . The pressure of the inert gas rises thereby causing the outflow openings  110  to become unsealed allowing gas to escape from the inflator into the airbag  300 . As the gas exits the pipe  100  and enters the airbag  300 , the airbag  300  deploys quickly and evenly along the side of the vehicle cab and covering the pillars  410 ,  420 ,  430  of the vehicle.  
         [0029]     The creation of a flow path through the openings  110  may occur, for example, due to the failure of a weakened portion  113  of the pipe  100  ( FIG. 3 ) or due to the failure of a seal member  115  ( FIG. 4 ). The opening  110  is configured so that the gas pressure required to rupture the seal and create the opening  110  can be predetermined.  
         [0030]     As shown in  FIGS. 3 and 4 , the gas outflow openings  110  may be positioned at various locations along the exterior of the pipe or tube  100 . The positioning of the openings  110  in a variety of locations may allow some or all of the airbag  300  to be inflated more quickly. For example, in an embodiment shown in  FIG. 6 , a length L 3  between adjacent openings may be between 10 and 20 mm, preferably about 15 mm.  
         [0031]     As is evident from the description above, the provision of an inflator along substantially the entire length of the airbag  300  allows the airbag to be inflated quickly and evenly to thereby provide improved protection to the occupant of the vehicle.  
         [0032]     The present invention also includes an embodiment of an inflator containing a gas generant or propellant as an alternative to the stored gas. According to yet another embodiment the inflator may contain a decomposing type material as the source of the pressurized gas for the airbag.  
         [0033]     As shown in  FIG. 5 , according to another embodiment of the present invention the pipe or tube  100  may contain a gas generant or propellant  500 . The inflator may also contain a standard igniter  200  or initiator assembly disposed at one end of the tube  100 . The igniter  200  receives a signal from a firing circuit or controller in order to initiate operation of the inflator.  
         [0034]     The propellant charge or gas generant  500  may extend for all, most, or same of the length of the pipe  100  thereby facilitating a substantially uniform gas generation once the propellant  500  is ignited. Uniform gas generation across the length of the inflator is desirable so that an airbag  300  is uniformly inflated. The plurality of gas outlets  110  fluidly communicate with the airbag once the propellant  500  is ignited and thereby provide sustained and uniform inflation over the length of the airbag. The propellant material may be selected from conventional known propellants such as disclosed in U.S. Patent Application Publication 2001/0045735 A1.  
         [0035]     For the aforementioned airbag embodiments, the present invention includes certain preferred parameters. These parameters are selected to ensure proper rapid, uniform and, if necessary, sustained inflation of the airbag.  
         [0036]     For example, referring now to  FIG. 6 , the length (L 1 ) of the inflation tube  100  may be carefully selected based on the length (L 2 ) of the side curtain type airbag  300 . As described above the tube  100  may be curved or linear. The length (L 1 ) corresponds to the length of the tube  100  as measured longitudinally along the geometric center of the tube  100 . As shown in  FIG. 6 , the length (L 2 ) of the airbag  300  is measured along the bottom edge of the deployed side curtain  300 . According to an embodiment of the present invention the ratio of length of the inflation tube to the length of the airbag (L 1 /L 2 ) is between about 0.7 and about 1.0. According to another embodiment of the present invention, the ratio (L 1 /L 2 ) is between about 0.75 and about 0.95. According to still another embodiment of the present invention, the ratio (L 1 /L 2 ) is between about 0.80 and about 0.90. According to another embodiment of the present invention, the ratio (L 1 /L 2 ) is about 0.85. In one embodiment, the length L 1  of the tube  100  is between about 1.0 and 3.0 mm, and is preferably between about 1.2 and 1.4 mm, preferably about 1.3 mm, or preferably between about 2.4 and 2.6 mm, preferably about 2.5 mm.  
         [0037]     Further by way of example, the number of openings or holes  110  can be determined based on the length (L 1 ) of the inflation tube  100 . According to a preferred embodiment, the openings  110  are positioned so that there are about 10 openings per meter along the length of the inflation tube  110 . According to another embodiment of the present invention, the number of openings is between 20 and 100 per meter of tube length, preferably between 50 and 80 per meter, and preferably about 70 per meter. The holes  110  are also preferably sized so that the area of the opening  110  is about 40 mm 2 , such as a circle having a diameter of 7 mm, but could range from 10 mm 2  to 100 mm 2 . However, as explained below the size of the opening may vary based on other parameters of the inflator.  
         [0038]     Another important parameter for improving airbag performance and reliability is the size of the openings  110  with regard to the size of the tube  100  (i.e., the length and cross-sectional area). For example, the size of each of the openings  110  is selected to have a cross-sectional area A 1  that is of predetermined size with regard to the cross-sectional area A 2  of the inflation tube or pipe  100 . The cross-sectional area A 1  of the opening  110  corresponds to the surface area of the portion of the tube  100  that is not present in order to accommodate the opening  110 , as shown in  FIG. 7 . The cross-sectional area A 2  of the tube  100  is determined based on a lateral cross-section substantially perpendicular to the longitudinal direction of the tube, also shown in  FIG. 7 . According to an embodiment of the present invention, the ratio of the cross-sectional area A 2  of the tube  100  over the cross-sectional area A 1  of the opening  110  is between about 20.0 and about 2.0. According to another embodiment the ratio (A 2 /A 1 ) is between about 16.0 and about 10.0. According to yet another embodiment the ratio (A 2 /A 1 ) is about 13.0.  
         [0039]     According to another embodiment of the present invention, the inflator tube  100  and the openings  110  are selected so that ratio of the size A 1  of the opening  110  to the length L 1  of the tube  100  is predetermined. For example, the ratio cross-sectional area to the length of the tube (A 1 /L 1 ) is between about 0.01 (mm 2 /mm) and 0.04 (mm 2 /mm). According to another embodiment the ratio (A 1 /L 1 ) is between about 0.02 (mm 2 /mm) and about 0.03 (mm 2 /mm). According to yet another embodiment the ratio (A 1 /L 1 ) is about 0.025 (mm 2 /mm).  
         [0040]     Referring now to  FIGS. 9   a  to  9   c , the present invention also includes a cascade inflator for an airbag that covers a vehicle length by approximately 60% to 100%.  FIG. 9   a  shows an inflator having a tube length X, the inflator connected to an automobile either inside or outside the automobile (both embodiments shown), the automobile having a length Y. In a preferred embodiment, a ratio of the length X of the inflator to the length Y of the car is between about 60% and about 100%, preferably between about 70% and 90%, and more preferably about 80%. In  FIG. 9   a , the inflator is configured and located to inflate the airbag along a side of the automobile.  FIG. 9   b  shows another embodiment of a cascade inflator for an airbag configured to inflate the airbag along a front of the automobile, and  FIG. 9   c  shows another embodiment of a cascade inflator for an airbag configured to inflate the airbag along a back of the automobile.  
         [0041]     WO 00/32447 discloses an inflator for use with a variety of airbags and seat belts. U.S. Patent Application Publication 2001/0045735 A1 discloses an elongated inflator. Both of the foregoing documents are incorporated by reference herein in their entireties. The scope of the present invention includes providing the inflators disclosed in the foregoing documents in combination with the additional improvements and benefits described above.  
         [0042]     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. 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.