Abstract:
A restraint assembly of a type including a seat belt assembly and a side impact air bag assembly. The seat belt assembly and side impact assembly are preferably mounted to a motor vehicle seat. The seat belt assembly includes one or two retractors, preferably each having roto pretensioners. A single gas source is used to actuate retractor pretensioning functions, as well as providing a gas source for initiating the production of inflation gas for the side impact air bag assembly. Preferably, these elements are all mounted to a motor vehicle seat.

Description:
FIELD OF THE INVENTION 
     This invention relates to automotive safety restraint systems and, in particular, to an active three-point seat belt system integrated with a side impact air bag. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Numerous designs of passive and active automotive occupant restraint systems are known for enhancing occupant protection in the event of a vehicle crash. Passive systems such as inflatable restraints such as air bags and automatically deployed seat belt systems are known. Active seat belt systems have been use for many decades and are manually deployed by the occupant. The conventional seat belt system uses three-points of connection with the vehicle structure and incorporates a lap belt section for engaging the occupant&#39;s lower torso and a shoulder belt section for engaging the occupant&#39;s upper torso. The seat belt restrains excursion of the occupant in the event of a vehicle impact or rollover event. In order to enhance the comfort and convenience provided by the seat belt system, retractors are normally used which permit the belt webbing to be extracted from and retracted onto the retractor, allowing movement of the occupant while maintaining the belt in close contact with the occupant. An inertia sensitive actuator locks the retractors when an impact or rollover event is detected, preventing free extraction of webbing in that vehicle condition. 
     Conventional three-point belt systems may use a single seat belt retractor for storing the seat belt which is used with a sliding latch plate. When fastening the belt, the occupant grasps the latch plate, inserts it to the buckle and the single retractor, usually coupled to the shoulder belt portion of the seat belt, takes up slack in the webbing while allowing movement for comfort and convenience of the occupant. In some seat belt systems, particularly those used in luxury vehicles, a two-retractor system is provided. For these systems, the latch plate is fixed to the webbing and separate upper and lower belt retractors are provided for the shoulder belt and lap belt sections, respectively. These systems do not require the latch plate to slide along the webbing. 
     Seat belt pretensioners are often used which, upon the detection of a condition leading to an imminent impact or rollover, or in the event of an actual vehicle impact or rollover, cause seat belt webbing to be automatically and forceably retracted to tighten the belt against the occupant. Such pretensioning can improve seat belt system performance. Electric motors may be used for so-called pre-pretensioning when an accident condition is detected. These systems are reversible so that the pretensioning effect can be reversed when the accident situation is no longer present. When immediate and powerful pretensioning action is required, for example upon the occurrence of a crash, gas assisted pretensioning devices are typically used. Two general types are used; a roto pretensioner is actuated by a gas source and uses a series of balls or other actuated devices which engage with the spool of a retractor to forceably cause retraction rotation of the spool. Another type uses a gas source acting on a piston in a cylinder to pull down a seat belt anchorage upon a deployment signal. 
     In addition to the advanced types of seat belt systems described previously, motor vehicles are now frequently equipped with side impact air bags. These devices include lower torso air bags types often mounted to the vehicle door or B-pillar trim, or mounted directed to the seat. These devices are often used in conjunction with side curtain air bags or other devices for restraining the upper torso and head of the occupant upon a side impact event. 
     For deployable safety devices including the pretensioners and air bags described previously which are examples of pyrotechnic safety device (PSDs), a crash sensor is coupled with a crash controller which has electrical signal firing lines which send crash signals to the various PSDs. Each of these firing lines requires dedicated vehicle wiring and separate inflator devices for creating inflation or deployment gas. Multiples of these PSDs add cost and complexity to the motor vehicle occupant restraint system. 
     In accordance with the present invention, vehicle components and system simplicity is achieved through combining a seat belt pretensioning system with an air bag, preferably a side impact air bag. In a preferred embodiment, both the side impact air bag and seat belt system are mounted to a motor vehicle seat. The seat belt system may include a single retractor for the shoulder belt section or a dual retractor system. A roto pretensioner is preferably used with one or both retractors, although other types of pretensioners can be used. A side impact air bag is provided and the pretensioner and air bag are actuated through a common gas source controlled by a single firing line. Significant efficiencies in design, weight, and reduction of complexity are provided by use of the common inflator with its single firing line to actuate both the pretensioner and side impact air bag. In another embodiment of this invention, two retractors are provided, each having roto pretensioners. As in the prior example, both the retractor pretensioners and side impact air bag are actuated by a common inflation gas source. 
     Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a pictorial view of a restraint system in accordance with the present invention shown mounted to a vehicle seat and showing various components in a cut away manner; 
         FIG. 2  is an assembly drawing of the restraint system in accordance with the present invention, shown apart from the vehicle seat; 
         FIG. 3  is a pictorial illustration of a dual spool retractor and side impact air bag in accordance with the present invention; and 
         FIG. 4  is a pictorial view of a dual spool retractor used in connection with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A motor vehicle restraint system in accordance with the present invention is illustrated in  FIG. 1  and generally designed by reference number  10 . Restraint system  10  principally comprises seat belt webbing  12 , divided into an upper or shoulder belt section  14 , and a lower or lap belt section  16 , for respectively restraining the upper and lower torso of a motor vehicle occupant. Restraint system  10  further includes latch plate  18  which can be affixed to seat belt buckle  20  in a conventional manner. 
     In use, as is conventional, an occupant sitting in seat  22  grasps latch plate  18 , extends the shoulder belt and lap belt sections  14  and  16  across their body and fastens the latch plate into buckle  20 . 
     With reference to  FIGS. 1 and 3 , the end of shoulder belt section  14  of the seat belt webbing is affixed to shoulder belt retractor  24  which has a spool  26  upon which the seat belt webbing  12  is wrapped. Shoulder belt retractor  24  operates in a conventional manner for stowing webbing to allow extension and retraction of the webbing as the belt system is deployed or while ii is not being used, and further permits extension and retraction of the webbing as the occupant moves for providing comfort and convenience. Shoulder belt retractor  24  would include, in accordance with conventional retractor design features, a rewind spring  27  and an emergency locking mechanism (not shown) which is typically inertia sensitive. These retractor control devices permit free extension and retraction of the seat belt webbing until a dynamic vehicle condition is encountered at which time the seat belt retractor locks to restrict extraction of webbing. 
     As further illustrated in  FIGS. 1 and 3 , restraint assembly  10  further preferably includes a lap belt retractor  28  having spool  30 . Various designs of lap belt retractor  28  may be provided. Lap belt retractor  28  provides a belt anchorage for restraining the lap belt portion  16  of the seat belt webbing. Lap belt retractor  28  may also incorporate features described previously in connection with shoulder belt retractor  24  such as emergency locking mechanisms and a rewind spring to permit free extension and retraction of the webbing. However, in one preferred embodiment, the lap belt retractor  28  would not include such features to permit free extension and retraction of the webbing, but rather would be provided for a pretensioning function, as will be described further. 
     In a preferred embodiment, shoulder belt retractor  24  and lap belt retractor  28  are mounted to a common frame  32 . This arrangement is shown in Applicant&#39;s copending U.S. patent application Ser. No. 11/082,567, filed on Mar. 17, 2005 entitled “Dual Spool Retractor”, which is hereby incorporated by reference. 
     Shoulder belt retractor  24  includes a roto pretensioner  34  which serves to retract or pretension shoulder belt section  14  of the webbing upon the detection of an impact condition. Roto pretensioner  34  is of generally conventional construction and is powered by deployment gas generated by a gas source  36  which communicates with a curved tube  38 . In accordance with conventional roto pretensioner design principles, a series of balls (not shown) are loaded into tube  38  and upon forcibly being moved along the tube  38  through a deployment gas source, these balls interact with a sprocket (not shown) affixed to spool  26  to cause pretensioning retraction of the retractor. This operating approach is also described in the previously mentioned co-pending patent application incorporated by reference herein. 
     Lap belt retractor  28  also preferably includes roto pretensioner  40  and tube  42  which operates in a manner equivalent to that described in connection with roto pretensioner  34 . In accordance with the present invention, both roto pretensioners  34  and  40  are actuated by deployment gas from a single gas source  36 . Thus, in response to a crash signal, initiation of gas source  36  via electrical signals on firing line  52  provides a rapid source of high pressure deployment gas which is sent through tubes  38  and  42  to cause pretensioning retraction of both retractors  24  and  28 . 
     Restraint system  10  in accordance with the present invention further includes side impact air bag assembly  44 . Air bag assembly  44  includes folded air bag  46  and inflation tube  48 . In accordance with the present invention, inflation tube  48  communicates directly with gas source  36  via tube  50  and receives deployment gas pressure from the same source. Thus, upon actuator of gas source  36 , the generated gas, in addition to being provided to roto pretensioners  34  and  40 , further provides inflation gas to deploy air bag  46 . Air bag assembly  44  may also include a so-called cold gas inflator  148  taking the place of inflator tube  48 . Inflator  148  would generate gas upon receiving high pressure gas from gas genenerator  36 , but does not require a separate firing line. Thus, for an embodiment of system  10  using cold gas inflator  148 , gas pressure from gas source  36  initiates the release of inflation gas. Such a configuration provides the benefit that gas source  36  does not need to have the gas generation capacity or proximity to air bag  46  to provide rapid inflation of the air bag, yet preserves the benefit of using a single firing line  52  to inflate the air bag and provide belt pretensioning. 
     In a preferred embodiment of the present invention, each of the aforementioned components including seat belt webbing  12 , retractors  24  and  28 , and air bag assembly  44  are mounted to seat  22 . Thus, when the seat is moved fore and aft to adjust to various occupants sizes, each of these components moves with the occupant. As mentioned previously, a fundamental benefit of the system in accordance with this invention is the use of a common gas source  36  and its associated firing line  52  to provide both seat belt pretensioning functions and side impact air bag inflation. 
     Various alternative configurations of the restraint assembly in accordance with this invention may be implemented while implementing the novel features of the present invention. For example, lap belt retractor  28  may be eliminated in favor of a fixed lap belt anchorage. In such an embodiment, gas source  36  would provide a gas source for shoulder belt retractor roto pretensioner  34  and would directly inflate or initiate inflation of air bag assembly  44 . Such a configuration would not provide dual pretensioning features but does provide the advantage of a common gas source and firing line for providing both seat belt pretensioning and side impact air bag inflation functions. 
     Further alternate embodiments of the present invention include various configurations for lap belt retractor  28 . Retractor  28  includes spool  30  which may be fixed to the retractor and is only actuated to rotate in a pretensioning rotational direction under the influence of roto pretensioner  40 . In this way, the lap belt retractor does not perform the function of a typical retractor of permitting free extension and retraction of webbing, but does provide the benefit of roto pretensioning of lap belt section  16 . Other configurations would provide a fully functioning lap belt retractor  28  having a rewind spring for free extension retraction of the webbing and an emergency locking mechanism for locking the lap belt retractor  28  upon specific vehicle dynamic conditions. For such a retractor assembly, it is possible further to use a common retractor control device as also described in Applicant&#39;s copending U.S. patent application Ser. No. 11/714,399, filed on Mar. 6, 2007 entitled “Inertia Actuator for Seat Belt Retractor”, which is also hereby incorporated by reference. 
     While the above description constitutes the preferred embodiment of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.