Abstract:
A safety device for use in an automobile that comprises a bolster and a telescoping mechanism. The telescoping mechanism extends when pressurized by the rapid introduction of a fluid. Following extension, the telescoping mechanism vents the fluid to allow the device to be retracted.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to the field of pyrotechnic safety devices. More specifically, the present invention relates to a safety device comprising a telescoping mechanism and a bolster. The telescoping mechanism is adapted to extend upon rapid introduction of a fluid and then retract by allowing the fluid to vent. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0002]     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:  
         [0003]      FIG. 1  is a side view of a knee protective telescoping pyrotechnic device mounted in an instrument panel of a vehicle.  
         [0004]      FIG. 2  is a perspective view of a telescoping pyrotechnic device.  
         [0005]      FIG. 3  is a perspective view of a telescoping mechanism in an extended position.  
         [0006]      FIG. 4  is a cross-sectional view of a telescoping mechanism in an extended position.  
         [0007]      FIG. 5  is a cross-section view of a telescoping mechanism in a collapsed position.  
         [0008]      FIGS. 6A-6F  are perspective views of a telescoping pyrotechnic device in different stages of deployment. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0009]     Described below are embodiments of a safety device for the restraint and protection of passengers in an automobile in the event of an impact. In one embodiment, the safety device is mounted in the instrument panel of an automobile and, upon impact, deploys toward the knees or lower legs of a passenger and resists the passenger&#39;s forward motion. The safety device deploys by pressurization with a fluid and depressurizes following deployment so that it does not pin the passenger inside the automobile.  
         [0010]      FIG. 1  shows a knee protective embodiment  10  of the safety device in an instrument panel  12  of an automobile.  FIG. 2  shows an enlarged view of knee protective pyrotechnic safety device  10 . The device comprises a knee bolster  20  with a front face  22  and a back face  24 . The back face  24  defines two receiving cavities  26  for receiving telescoping mechanisms  30 . A locking plate  28  is welded on back face  24  across the cavity  26  to lock the telescoping mechanism in place. The knee bolster may be manufactured by any suitable method such as conventional injection molding. In an embodiment (not shown) of the device for use in the door of an automobile, the bolster is a pelvic restraint that conforms to the contours of the door. Knee bolster  20  and the pelvic restraint are examples of means for restraining a passenger of an automobile following an impact.  
         [0011]     The embodiment shown in  FIG. 2  comprises two telescoping mechanisms  30  adapted to extend and deploy upon an impact.  FIGS. 3 and 4  are perspective views of telescoping mechanism  30  in the extended position. Telescoping mechanism  30  comprises a base  34  for attaching the telescoping mechanism to a mounting bar  60  (shown in  FIG. 2 ) and an attachment disc  36  for insertion into the receiving cavity in back face  24  of bolster  20 . A stem  38  is connected to an attachment tip such as attachment disc  36 . In one embodiment, attachment disc  36  is flexibly mounted in receiving cavity  26  to permit the device to respond to different impacts over the life of the device.  
         [0012]     Telescoping mechanism  30  further comprises a plurality of sections  40   a - e  that are sized to collapse into one another.  FIG. 5  is a cross-sectional view of telescoping mechanism  30  in a collapsed position. Referring now to  FIG. 4 , each section  40   a - d  comprises a sidewall  42   a - d , shoulder  44   a - d  and lip  46   a - d . Outermost section  40   e  comprises a sidewall  42   e , shoulder  44   e  and is attached to base  34 . Center section  40   a  is positioned at the center of the sections. Section  40   a  comprises a top end  41   a  that is attached to stem  38 . While the sections shown in the figures are concentric cylinders, the invention is not intended to be limited to a specific shape. Other shapes, such as squares or pyramids, may be used. The sections may be formed by any suitable method of manufacturing. In one embodiment, the section is stamped metal.  
         [0013]     Telescoping mechanism  30  further comprises a pyrotechnic fluid generator  50  in fluid communication with sections  40 . Upon impact, fluid generator  50  rapidly introduces fluid against stem  38  and into center section  40   a , causing stem  38  and center section  40   a  to extend away from the other sections. As more fluid is introduced, more pressure is exerted on center section  40   a  and stem  38 , extending the remaining sections  40 . While it is expected that center section  40   a  would extend first, nothing herein restricts the scope of the claims to require the center section to extend first. Telescoping mechanism  30  is an example of means for extending the restraining means from a storage position to a deployed position.  
         [0014]     As the telescoping mechanism deploys, sidewall  42  of each section  40  slides along shoulder  44  of the adjacent section. The pressure of the fluid forces the sidewall of the section extending against the shoulder of the adjacent section, thus maintaining a closed system. Each section is prevented from further extension by lip  46  of the adjacent section. Once the sections are fully extended, the seal between the lip and shoulder of adjacent sections is incomplete so that the fluid can vent after deployment and the device can be collapsed sufficiently so that the passenger can move out of the automobile. Stated otherwise, the sections form an imperfectly sealed chamber. In addition to incomplete seals or as an alternative to incomplete seals, one or more of the sections may also contain vent holes to allow the fluid to escape the chamber. O-rings may be located between each section to seal the sections together. The leak rate of the fluid of the telescoping mechanism may be tuned for different crash impulses.  
         [0015]     In one embodiment, the device is pressurized for up to 100 milliseconds, and then slowly depressurizes. The device may also comprise at least one section sensitive to over-pressurization so that the sidewall of the section will burst upon over-pressurization. Such a section would be beneficial when the passenger is positioned close to the instrument panel or for out-of-position deployments.  
         [0016]     Fluid generators typically comprise gas generants, a squib, and wire terminals. The wire terminals are connected to a sensor. When the sensor detects an impact, the wire terminals send a signal to the squib. The squib ignites and causes the gas generants to activate and rapidly generate gas. The fluid generating cylinder may be attached to the sections of the telescoping mechanism by a lip at the base of the outermost section. In addition, an o-ring may be positioned inside the lip of the outermost section to seal the telescoping mechanism sections to the fluid generating cylinder.  
         [0017]      FIGS. 6A through 6F  show perspective views of an embodiment of the safety bolster in different stages of deployment.  FIG. 6A  is a view of the device in the collapsed, stored position.  FIGS. 6B-6E  show progressively extended positions and  FIG. 6F  shows the safety bolster in its fully extend position. Fluid generator  50  is an example of a fluid generating means for rapidly introducing fluid into the extending means.  
         [0018]     The device may be mounted on any portion of an automobile for which restraint of a passenger is described. The illustrated embodiment is designed to be mounted in an automobile instrument panel, with front face  22  facing the knees and lower legs of a passenger of the automobile. This knee bolster embodiment may be mounted on the automobile&#39;s cross-car beam. In another embodiment, the device may be mounted in a door panel as a pelvic restraint.  
         [0019]     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. It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only 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.