Patent Publication Number: US-2009218798-A1

Title: Dual mode inflatable curtain cushion

Description:
TECHNICAL FIELD  
     The present invention relates generally to the field of automotive protective systems. More specifically, the present invention relates to a system for selectively venting inflation gases from an inflatable curtain cushion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Understanding that drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  is a side elevation view of one embodiment of an inflatable curtain cushion assembly mounted in a vehicle. 
         FIG. 2  is a side elevation view of the inflatable curtain cushion assembly of  FIG. 1 . 
         FIG. 3A  is a cross-sectional view of the inflatable curtain cushion assembly of  FIG. 1  during early deployment. 
         FIG. 3B  is a cross-sectional view of the inflatable curtain cushion assembly of  FIG. 1  during full deployment. 
         FIG. 3C  is a cross-sectional view of the inflatable curtain cushion assembly of  FIG. 1  during late deployment. 
         FIG. 4  is a side elevation view of another embodiment of an inflatable curtain cushion assembly mounted in a vehicle. 
         FIG. 5  is a side elevation view of another embodiment of an inflatable curtain cushion assembly. 
     
    
    
     INDEX OF ELEMENTS IDENTIFIED IN THE DRAWINGS 
     
         
           10  vehicle 
           12  roof rail 
           15  instrument panel 
           20  A-pillar of vehicle 
           25  B-pillar of vehicle 
           30  C-pillar of vehicle 
           35  D-pillar of vehicle 
           100  inflatable curtain cushion assembly 
           110  inflatable curtain cushion 
           112  first side 
           113  void 
           114  second side 
           115  gas inlets 
           116  tethers 
           117  first chamber seam 
           118  second chamber seam 
           119  mounting tab 
           120  inflator 
           122  inflator tubes 
           130  first chamber 
           132  inflation cells 
           140  second chamber 
           150  one-way valve 
           10  vehicle 
           12  roof rail 
           15  instrument panel 
           20  A-pillar of vehicle 
           25  B-pillar of vehicle 
           30  C-pillar of vehicle 
           35  D-pillar of vehicle 
           400  inflatable curtain cushion assembly 
           410  inflatable curtain cushion 
           415  gas inlets 
           416  tethers 
           420  inflator 
           422  inflator tubes 
           430  first chamber 
           440  second chamber 
           450  one-way valve 
           460  vent 
           500  inflatable curtain cushion assembly 
           510  inflatable curtain cushion 
           515  gas inlet 
           516  tethers 
           520  inflator 
           522  inflator tubes 
           530  first chamber 
           540  second chamber 
           550  one-way valve 
           570  gas guide 
           572  junction 
       
    
     DETAILED DESCRIPTION  
     Described below are embodiments of apparatus, methods, and systems for inflatable curtain venting. In the following description, numerous specific details are provided for a thorough understanding of the embodiments of the invention. However, those skilled in the art will recognize that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. 
     In addition, in some cases, well-known structures, materials, or operations are not shown or described in detail in order to avoid obscuring aspects of the invention. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     Inflatable cushion systems are widely used to minimize occupant injury in a collision scenario. Cushion modules have been installed at various locations within a vehicle, including, but not limited to, the steering wheel, the instrument panel, within the side doors or side seats, adjacent to roof rail of the vehicle, in an overhead position, and at the knee or leg position. In the following disclosure, “airbag” may refer to an inflatable curtain airbag, overhead airbag, front airbag, or any other airbag type. 
     Inflatable curtain cushions typically extend longitudinally within the vehicle and are usually coupled to or next to the roof rail of the vehicle. In an undeployed state, inflatable curtain cushions are typically rolled, folded, or a combination of both, and retained in the undeployed configuration by wrapping at attachment points, or by being enclosed in a sock. In a deployed state, an inflatable curtain cushion may cover at least a portion of the side windows and the B-pillar of the vehicle. In some embodiments, inflatable curtain cushions may extend from the A-pillar to the C-pillar of the vehicle. In alternative embodiments, inflatable curtain cushions may extend from the A-pillar to the D-pillar of the vehicle. 
     In a collision event, the inflatable curtain cushion may be inflated by an inflator and changes conformation from rolled and/or folded to an extended deployed state. The amount of gas from the inflator that is retained within the inflatable curtain determines how hard or soft the cushioning of the curtain will be. 
     Inflatable curtain cushions may be configured to serve two functions: cushioning and anti-ejection. During a collision event, the curtain may cushion the head and upper body of an occupant, and during a roll-over event, the cushion may function to help retain the occupant within the vehicle. These two functions require significantly different time-scales. Typically, inflatable curtains are configured to provide cushioning during a side impact event for about 500 milliseconds. However, during a roll-over event, the inflatable curtain may need to cushion an occupant and protect against occupant ejection for up to seven seconds. Inflatable curtain cushions help mitigate the risk of occupant ejection by forming a barrier between the occupant and the side windows. 
     Inflation gas retention for an extended length of time, such as up to seven seconds, can be accomplished by manufacturing an inflatable curtain using high thread-count fabrics, sealed seams, and fabrics that have been coated with a substance that makes the fabric less porous to inflation gas. However, these manufacturing practices are more expensive than those required for gas retention for shorter lengths of time, such as less than 500 milliseconds. 
     It would be advantageous to provide an inflatable curtain cushion that could efficiently fulfill the dual functions of occupant cushioning and occupant retention without the high cost of manufacturing the entire inflatable curtain by more expensive practices. Embodiments disclosed below provide a reduced-cost dual mode inflatable curtain cushion that has an upper chamber configured to cushion an occupant for less than one second, and a lower section that may retain inflation gas for several seconds up to about seven seconds. 
       FIG. 1  represents one embodiment of an inflatable curtain cushion assembly  100  from a side elevation view, wherein assembly  100  is mounted inside a vehicle  10  adjacent a roof rail  12  and beside an instrument panel  15 . Inflatable curtain cushion assembly  100  is depicted in a deployed state. Inflatable curtain cushion assembly  100  may comprise an inflatable curtain cushion  110  and an inflator  120 . 
     Inflatable curtain cushion  110  may comprise two chambers, a first chamber  130  and a second chamber  140 . The shape of inflatable curtain cushion  102  depicted in  FIG. 1  is for illustrative purposes only, and may be altered. Inflatable curtain cushion  110  may be configured to fit within the side window wells of vehicle  10 . 
     Inflatable curtain cushion  110  may comprise a contiguous piece of material manufactured using a one-piece woven technique or may be manufactured by cutting and sewing a nylon material, which is well known in the art. Curtain  110  comprises a first side and a second side of material, forming a void between them, into which inflation gas may be forced thereby inflating the curtain. First and second sides may be formed from a continuous sheet of material. Curtain  110  may be anchored to a vehicle structure via mounting tabs disposed on the outer edge of curtain  110  and by tethers  116 . Tethers  116  may be coupled to curtain  110  by sewing, gluing, RF welding or by any other suitable manner. Further, tethers  116  may comprise extensions of curtain  110 . Tethers  116  are anchored to a vehicle structure, such as A-pillar  20  and D-Pillar  35 . 
     Inflator  120  is anchored to roof rail  12 , and may be either a pyrotechnic device, or a stored gas inflator. Inflator  120 , and may comprise inflator tubes  122 , which act as conduits through which inflation gas travels from the inflator to the void formed by the two sides of inflatable curtain cushion  110 . Inflator  120  is in electronic communication with vehicle sensors which are configured to detect vehicle collisions and rollovers; upon detection of predetermined conditions, the sensors activate the inflator and inflatable curtain cushion  110  is rapidly inflated. 
     First chamber  130  of inflatable curtain  110  runs substantially horizontally, with an upper edge of first chamber  130  running substantially parallel with and adjacent to roof rail  12  when curtain  110  is in the deployed configuration. First chamber  130  may comprise one or more inflation chambers, which may be of any shape; the rectangular inflation chambers depicted in  FIG. 1  are for illustrative purposes only. First chamber  130  may not run the full horizontal length of curtain  110 , and does not comprise the full vertical height of curtain  110 . 
     In the embodiment of  FIG. 1 , second chamber  140  is formed from the same piece of material as first chamber  130 , however, in other embodiments, second chamber  140  may be fabricated as a separate piece which is coupled to first chamber  130 . Second chamber  140  is substantially horizontally oriented and is disposed below first chamber  130 . Inflatable curtain  110  may have a configuration such that the bottom longitudinal edge of second chamber  140  may be disposed at or below the bottom of a side window in a vehicle. 
     A one-way valve is disposed between the first and second sides of first chamber  130  and enables second chamber  130  to be in fluid communication with first chamber  130 , but not vice-versa. When inflation gas pressure is higher in first chamber  130 , gas will flow through one-way valve  150  into second chamber  140 , however one-way valve  150  is configured such that gas cannot back-flow into first chamber  130  from second chamber  140 . One-way valve  150  may comprise a fabric, metal, or plastic valve and may comprise a non-mechanical or a mechanical valve. 
     During a collision or roll-over event, vehicle sensors may activate inflator  120  such that inflatable curtain cushion  110  changes conformation from a stored configuration to a deployed configuration. First chamber  130  is configured such that it may provide impact cushioning to an occupant for a short duration of time, such as about 500 milliseconds before it deflates to ambient air pressure. First chamber  130  is configured to cushion the upper body and head of an occupant and protect the occupant from striking a B-pillar  25  or a C-pillar, depending on the configuration of the vehicle in which the person is an occupant. In the event that an occupant strikes the inflatable curtain while inflated, first chamber  130  may soften the cushioning by rapidly venting inflation gas via vents in the membrane of the inflatable curtain, via unsealed seams, via the porosity of the material itself, or via a combination of the three. 
     Upon inflation, the length of second chamber  140  is necessarily shortened due to its circular shape; the shortening of second chamber  140  helps to tension inflatable curtain  110 . Thus, second chamber  140  may help to mitigate the possibility of occupant ejection during a roll-over event by remaining inflated for up to seven seconds after inflation, and thereby maintaining the tautness of inflatable curtain  110 . In this way, inflatable curtain  110  remains in place and properly positioned so that it may act as an effective barrier to occupant ejection through a side window. Further, second chamber  140  may cushion an occupant during a collision event or a roll-over event. 
     Thus, second chamber  140  is configured to retain inflation gas at a pressure higher than an ambient air pressure for a predetermined period of time, up to about seven seconds. The retention of inflation gas within second chamber  140  at a pressure higher than the ambient air pressure will at least partially maintain a tension on the curtain cushion such that it stays in place and acts as a barrier to occupant ejection. 
       FIG. 2  depicts the inflatable curtain cushion assembly  100  of  FIG. 1 . More visible in this view are the gas inlets  115  of cushion  110 , which receive inflation gas from inflator tubes  122  of inflator  120 . Gas inlets  115  may comprise contiguous extensions of first chamber  130 . First chamber seams  117  may comprise stitching that is not air-tight, or an air-tight seam generated via RF welding or gluing, or a combination of stitching and seam seals. First chamber seams  117  may form inflation cells  132 , which are depicted as being rectangular, but may be of any shape. Typically, inflation cells  132  are contoured in accordance with a specific vehicle, such that cushion curtain  110  may offer better occupant protection. Left and right halves of first chamber  130  are depicted in  FIG. 2  as being independent inflation cells, however, in alternative embodiments, first chamber  130  may comprise one inflation cell or at least two inflation cells in fluid communication. 
     Mounting tabs  119  may comprise extensions of curtain cushion  110 , or may comprise separate pieces that are attached to curtain cushion  110 . Mounting tabs are primarily positioned along the top edge of curtain cushion  110  such that the curtain cushion may be mounted along the roof rail of a vehicle. 
     Second chamber  140  is formed from the material comprising curtain cushion  110  by second chamber seam  118 , which is depicted in  FIG. 2  as being stitching. Seam  118  may comprise stitching that is not air-tight or air-tight stitching, further it may comprise an air-tight seam generated via RF welding or gluing, or a combination of stitching and seam seals.  FIG. 2  depicts curtain cushion  110  as having four one-way valves  150 , however, in alternative embodiments curtain cushion  110  may comprise one or more one-way valves. 
     One-way valves  150  are disposed in between the first and second sides of curtain cushion  110  and is also disposed between first chamber  130  and second chamber  140 . One-way valves  150  are held in place via stitching, and are disposed into areas where first chamber seam  117  and second chamber seam  118  are interrupted. On either longitudinal side of one-way valves  150 , first chamber seam  117  and second chamber seam  118  continue such that the only path by which inflation gas may travel between first chamber  130  and second chamber  140  is by one-way valves  150 . 
     One-way valves  150  may comprise non-mechanical valves, such as pieces of fabric, or mechanical valves manufactured from plastic, metal, or a combination of fabric, plastic, or metal. Additionally, one-way valves  150  may be configured such that a predetermined magnitude of gas pressure is required in first chamber  130  before one-way valves  150  are opened and allow inflation gas to enter second chamber  140 . Alternatively, one-way valves  150  may be configured such that inflation gas may freely travel from first chamber  130  to second chamber  140  whenever there is a greater magnitude of gas pressure in first chamber  130 . Any conventional one-way valve may be used. 
       FIGS. 3A to 3C  depict inflatable curtain cushion assembly  100  of  FIG. 1  from a front elevation cross-sectional view during early deployment, full deployment, and late deployment, respectively. In  FIG. 3A , inflation gas, (depicted as arrows) enters curtain cushion  110  via inflator tubes  122  and begins to fill a void  113  formed by first side  112  and second side  114 . During early curtain cushion deployment, the magnitude of gas pressure in first chamber  130  may slightly exceed that of second chamber  140 , even if one-way valve  150  does not require a predetermined pressure differential to allow gas transfer. 
     During full curtain cushion deployment depicted in  FIG. 3B , first chamber  130  and second chamber  140  are inflated and comprise an pressure above an ambient air pressure and inflation gas may rapidly vent from first chamber  130  via discrete vents, unsealed seams, porosity of the material which comprises first chamber  130 , or a combination of these causes. If an occupant strikes first chamber  130 , additional inflation gas may be pushed into second chamber  140 , however, due to one-way valve  150 , inflation gas may not travel from second chamber  140  back to first chamber  130 . 
       FIG. 3C  depicts late curtain cushion deployment, wherein first chamber  130  has vented inflation gas such that first chamber  130  has returned to a pressure that is at or near ambient air pressure. Second chamber  140  remains inflated at a pressure above ambient air pressure and may remain inflated for an extended time period, such as up to seven seconds. 
       FIG. 4  is a side elevation view of another embodiment of an inflatable curtain cushion assembly  400 . Inflatable curtain cushion assembly  400  is configured similarly and is configured to function similarly to cushion assembly  100 , except the differences described below. Cushion assembly  400  is manufactured using a cut and sew technique, whereas cushion assembly  100  is manufactured using a one piece woven technique. Inflatable curtain cushion assembly  400  is mounted inside a vehicle  10  adjacent a roof rail  12  and beside an instrument panel  15 . Inflatable curtain cushion assembly  400  is depicted in a deployed state and is anchored to an A-pillar  20  and a D-pillar  35  via tethers  416 . 
     Since first chamber  430  is configured to vent inflation gas more rapidly, a cut and sew technique allows the first chamber  430  to be manufactured from a woven material with a thread count that is lower than the material from which second chamber  440  is manufactured. As first chamber  430  comprises a majority of the surface area of curtain cushion  410  and the lower thread count material is less expensive than the higher thread count material, this technique lowers the cost of manufacturing a curtain cushion such as the embodiment shown at  410 . Additionally, curtain cushion  410  may be manufactured using a combination of one piece woven and cut and sew techniques, including by utilizing an integral sheet with sections having different thread counts. 
     First chamber  430  comprises two pieces of material which are sewn together (first chamber seam  417 ) to form a first side and a second side of first chamber  430 . First chamber  430  further comprises vents  460 , which are in fluid communication with a void formed by first and second sides of cushion  410  and are configured rapidly vent inflation gas. First chamber  430  receives inflation gas via gas inlets  415 , which in turn, receives gas from inflator gas tubes  422 . Inflator  420  is depicted as being mounted in the roof rail  12 , however in alternative embodiments, inflator  420  (and other inflators described herein) may be disposed in other positions. 
     Second chamber  440  may be manufactured from one or two pieces of a woven material with a higher thread count than that of first chamber  430 . Second chamber  440  does not touch first chamber  430 , except at one-way valves  450 ; alternatively second chamber  440  may be sewn to first chamber  430 . Additionally, second chamber  440  may be coupled to first chamber  430  via loops of material that are attached to first chamber  430  and encircle second chamber  440 . First chamber  430  and second chamber  440  may be individually tethered to a vehicle structure, or they may be tethered together. 
       FIG. 5  is a side elevation view of another embodiment of an inflatable curtain cushion assembly  500 , which is intended to function similarly to the above described curtain cushion assemblies, however the configuration of first chamber  530  and second chamber  540  differs from previously described curtain cushion assemblies. Curtain cushion  510  is depicted as comprising a single piece of material manufactured using a one piece woven technique, but may alternatively be manufactured using a cut and sew technique, wherein the first chamber  530  and second chamber  540  comprise different pieces of material. Additionally curtain  510  may be manufactured using a combination of one piece weaving, and cut and sew techniques. 
     First chamber  530  may comprise a gas inlet  515  which receives inflator tube  522  such that inflation gas from an inflator  520  may enter first chamber  530  via gas inlet  515 . In other embodiments, gas inlet  515  may comprise a different shape and there may be more than one gas inlet  515  present to receive more than one inflator tube  522 . 
     First chamber  530  is depicted has having multiple rectangular shaped inflation cells, however in alternative embodiments, the quantity, volume, and shape of inflation cells within first chamber  530  may vary. Additionally, first chamber  530  is depicted as having two gas inlets  515  which are integral extensions of first chamber  530  and are coupled to inflator tubes  522 . In alternative embodiments, first chamber  530  may comprise less than two gas inlets  515 . Thus, the inflation cells of first chamber  530  may not be supplied with inflation gas from two different gas inlets  515 , and therefore may be more highly integrated and in greater fluid communication than depicted in  FIG. 5 . 
     Second chamber  540  may comprise a woven material with a thread count higher than the material from which first chamber  530  was manufactured. Alternatively, or in combination with the above, second chamber  540  may be more heavily coated than first chamber  530  with a sealing compound that blocks the apertures between the threads of the woven material from which the chambers are manufactured. Finally, second chamber  540  may be manufactured using techniques which result in air-tight seams  518 , or second chamber  540  may be manufactured from a combination of the above techniques which, individually or in combination, may render second chamber  540  less porous to inflation gas. 
     Reducing the porosity of second chamber  540  may result in second chamber  540  remaining above a predetermined pressure for at least a predetermined time, which time is longer than the time at which first chamber  530  remains at a predetermined pressure. Thus, second chamber  540  may help inflatable curtain cushion  510  to remain taut during a roll-over event thusly making curtain cushion  510  a more effective barrier to occupant ejection. 
     Second chamber  540  is depicted in  FIG. 5  as defining one large, horizontally oriented inflation cell. However the configuration of second chamber  540  depicted in  FIG. 5  is strictly for illustrative purposes and in alternative embodiments, second chamber  540  may comprise multiple inflation cells that may or may not be substantially horizontally oriented. 
     Gas guide  570  may comprise a contiguous extension of second chamber  540 , or may comprise a separate piece of material. Second chamber  540  receives inflation gas via gas guide  570 , which in turn receives inflation gas from inflator tube  522 . A one-way valve  550  is disposed between inflator  520  and second chamber  540 . In the depiction of  FIG. 5 , one-way valve  550  is disposed very near inflator tube  522 , however, one-way valve  550  may be disposed anywhere along gas guide  570 , including at the junction  572  of gas guide  570  and second chamber  540 . Thus, second chamber  540  is configured to retain inflation gas at a pressure higher than an ambient air pressure for a predetermined period of time, up to about seven seconds. 
     If an occupant strikes first chamber  530 , inflation gas may be forced into second chamber  540  via one-way valve  550 , thus increasing the gas pressure within second chamber  540 . In this way, one-way valve may help to cushion the occupant by venting inflation gas from first chamber  530  to second chamber  540 . Additionally, a higher gas pressure within second chamber  540  may allow curtain cushion  510  to remain a more effective barrier to occupant ejection for a longer period of time than if an occupant did not strike first chamber  530 . 
     The methods disclosed herein comprise one or more steps or actions for performing the described method. The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and/or use of specific steps and/or actions may be modified. 
     Without further elaboration, it is believed that one skilled in the art can use the preceding description to utilize the invention to its fullest extent. The examples and embodiments disclosed herein are to be construed as merely illustrative and not a limitation of the scope of the present invention in any way. It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. In other words, various modifications and improvements of the embodiments specifically disclosed in the description above are within the scope of the appended claims. The scope of the invention is therefore defined by the following claims. Note also that elements recited in means-plus-function format are intended to be construed in accordance with 35 U.S.C. §112 ¶6.