Automotive knee bolster

Abstract: An instrument panel 10 for an automotive vehicle includes a substructure 14 that extends across the width of a passenger compartment of the vehicle and is secured to side pillars 12 of the vehicle body. A pair of laterally spaced knee bolsters 24 and 25 each include a retainer 26, 27 that has a rearwardly facing wall 28 that is located at knee height, and a pair of integrally attached, vertically spaced struts 30 that are attached to a lower channel 16 of the substructure 14 to form a first box structure 32 for absorbing impact energy. A front channel 36 is disposed in front of the lower channel 16 and securely attached to the substructure 14 of the instrument panel 10. The attached channels 16 and 36 provide a cross car duct 44 for wiring or air distribution and a second box structure 42 for absorbing energy when the knee bolster 24 or 25 is impacted in a vehicle collision.

Description: BACKGROUND OF THE INVENTION This invention relates generally to automotive vehicles and more particularly to an automotive instrument panel for an automotive vehicle that includes a knee bolster for protecting the knees of front seat occupants in the event of a collision. Federal Motor Vehicle Safety Standard 208 mandates that the lower instrument panel of an automobile prevent knee damage in a thirty (30) mile per hour vehicle impact. Conventional approaches use an open cell or resilient foam on a steel backed plastic or composite plate. The U.S. Patent 4,934,736 granted to Marinus Huisman June 19, 1990 discloses a knee restraining device according to the preamble of claim 1 and comprises an inflexible, hollow support member and a flexible deformation element that includes a sheet metal shell and a foam layer. Other approaches utilize permanent or non-elastic deformation of structural members. For instance, U.S. Patent 4,978,136 granted to Norihiro Tomita et al December 18, 1990 discloses an automotive knee protector comprising plates that are attached to V-shaped arms by shock absorbing members that are deformed responsive to a crash. Another example is U.S. Patent 4,400,011 granted to Yoshio Matsuno August 23, 1983 which discloses a vehicle body construction comprising knee restraining members that are channel-shaped and collapsible or deformable non-elastically. The members are preferably covered with a suitable padding. SUMMARY OF THE INVENTION The object of this invention is to provide an instrument panel that has knee bolsters that absorb impact energy primarily by elastic deformation of structural components. A feature of the invention is that the instrument panel incorporates a "double box" approach that absorbs knee impact energy effectively. Another feature of the invention is that the instrument panel incorporates back-to-back structural boxes that deform in three dimensions to absorb knee impact energy effectively. Yet another feature of the invention is that the instrument panel includes a knee bolster retainer that cooperates with a substructure of the instrument panel to provide a box structure for absorbing impact energy. Still yet another feature of the invention is that the instrument panel includes a structural member that cooperates with a substructure of the instrument panel to provide a box structure for absorbing impact energy and to provide a cross car duct for wiring or air distribution. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings wherein like references refer to like parts and wherein: Figure 1 is an exploded perspective partial view of an automotive vehicle having an instrument panel that includes a knee bolster in accordance with the invention; and Figure 2 is a section of the instrument panel taken substantially along the line 2-2 of figure 1 looking in the direction of the arrows. DESCRIPTION OF THE INVENTION Referring now to the drawing, figure 1 shows a portion of an automotive vehicle at the front of the passenger compartment comprising an instrument panel 10. The instrument panel 10 extends across the width of the passenger compartment and is secured to side pillars 12 of the automotive vehicle body construction commonly referred to as "A" pillars in a conventional manner. The instrument panel 10 comprises a substructure 14 that forms a cross car structural member of the vehicle body construction when it is secured to the side pillars 12. The substructure 14 may be secured in any suitable manner, for instance by bolts 15. The substructure 14 is preferably molded of a tough unfilled structural thermoplastic material, such as polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS). The substructure 14 may also be made of metal, a plastic composite or any other automotive structural material. The substructure 14 includes a lower channel 16 comprising a back wall 18 and sloped side walls 20 or other suitable shape for cooperatively forming a box structure. The channel 16 extends across the width of the passenger compartment and includes a central portion that is behind a center stack 22 of the instrument panel 10 that is provided for accessories such as a radio; a tape or disk player; controls for a heating, ventilating and air conditioning (HVAC) system, etc. An offset portion of the channel 16 on the driver's side accommodates a steering column (not shown). The substructure 14 may also be secured to the center stack 22. The instrument panel 10 includes a pair of knee bolsters 24 and 25 that are located on opposite sides of the center stack 22 and that comprise retainers 26 and 27 respectively. The retainers 26 and 27 have a curved convex wall 28 that faces rearwardly toward the front seat occupants seated behind the instrument panel 10. The rearward facing wall 28 is located at knee height. The knee bolster retainers 26 and 27 may be separate molded parts as shown or an integral lower extension of the retainer of the instrument panel 10. The retainers 26 and 27 further comprise a pair of integrally attached, vertically spaced struts 30 that extend forwardly and are attached to the corners of the lower channel 16 as best shown in figure 2. The struts 30 are securely attached to the lower channel 16 in any suitable manner, for example by adhesive as shown or mechanical fasteners or the like. Each knee bolster retainer 26 and 27 thus forms a first box structure 32 of generally rectangular shape in conjunction with the lower channel 16 for absorbing impact energy as explained below. Furthermore, this design also allows several bolsters to fit substructure 14 so that several different styles can be provided for a car line using a single substructure. The knee bolster retainers 26 and 27 may be made of any structural thermoplastic material that is compatible with the material of the substructure 14. Examples of suitable materials are polycarbonate/ABS, polypropylene (PP) and polyurethane (PU). The knee bolsters 24 and 25 may include a suitable decorative covering 34 which conventionally comprises a soft flexible skin of a plastic material such as polyvinyl chloride or urethane. An expanded polyvinyl chloride or urethane material that has an integral backing layer of resilient foam may be used instead to enhance the softness of the decorative covering 34 if desired. A separate layer of resilient urethane foam or the like can also be used in place of or in addition to the integral backing layer for an enhanced cushioning effect. The instrument panel 10 further comprises another structural member in the form of a front channel 36 that may be a mirror image of the lower channel 16 of the substructure 14 of the instrument panel 10. This front channel 36 comprises a front wall 38 and sloping side walls 40 that extend across the width of the passenger. The front channel 36 is disposed in front of the lower channel 16 and it is securely attached to the instrument panel substructure 14 in any suitable manner, for example, by fusing mating flange portions at the free ends of the side walls 20 and 40. The front channel 36 which may be a structural plastic such as PC/ABS or a metal such as steel or a combination of both serves two important functions. It provides a duct close out for the lower channel 16 of the instrument panel 10 so that a cross car duct 44 for wiring or for air distribution in connection with the heating, ventilating and air conditioning (HVAC) system of the vehicle is provided by the two channels 16 and 36. The front channel 36 also provides a second box structure 42 of generally hexagonal shape in conjunction with the lower channel 16 of substructure 14 for absorbing energy when the knee bolster 24 or 25 is impacted in a vehicle collision. Channel 36 and substructure 14 are both structural members. Either or both may extend up vertically to provide structural support for the instrument panel 10 above the knee bolster area. When a conventional knee bolster is impacted in a vehicle collision, the energy is absorbed primarily by deflection of resilient foam with some deformation of structural components. On the other hand, when the knee bolster 24 or 25 is impacted in a vehicle collision, the resulting energy is absorbed primarily by elastic deformation of structural components material with some deflection since the back-to-back box structures 32 and 42 deform in three dimensions. This reduces the amount of deflection that is necessary in conventional knee bolsters and saves space so that the knee bolsters do not need to protrude as far into the passenger compartment. The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.

Claims: An instrument panel for an automotive vehicle with a body having side pillars (12), the instrument panel (10) including substructure (14) for extending across the width of a passenger compartment of the vehicle to support the instrument panel (10) with respect to the side pillars (12) and carrying a knee bolster (24, 25) thereon, characterized by: the knee bolster (24,25) having a retainer (26,27) with a rearwardly facing wall (28) and vertically spaced struts (30); said substructure (14) having a first portion (16) that is adapted to extend across substantially the full width of the passenger compartment and said first portion (16) being joined to said vertically spaced struts (30) to form a first box structure (32) for absorbing impact energy from within the passenger compartment when the knee bolster is impacted in a vehicle collision; said substructure (14) having a second portion (36) that is joined to said first portion (16) to form a second box structure (42) for absorbing impact energy from within the passenger compartment when the knee bolster is impacted in a vehicle collision. The instrument panel of claim 1 and further characterized by the knee bolster (24,25) comprising laterally spaced segments (24,25). The instrument panel of claim 1 or 2 and further characterized by said first and second portions (16,36) forming a cross vehicle duct (44) for extending between the side pillars (12) and for accommodating either wiring or an air distributor. The instrument panel of claim 1, 2 or 3, wherein said first box structure (32) and said second box structure (42) are disposed back-to-back. The instrument panel of any preceding claim, wherein said first portion (16) comprises a back wall (18) that extends across the width of the vehicle compartment and said second portion (36) comprises a front wall (38) that is a mirror image of said back wall (18) and extends across the width of the vehicle compartment. The instrument panel of claim 5, wherein said first portion (16) comprises said back wall (18) and sloping side walls (20) defining a rear channel (16) and said second portion (36) comprises said front wall (38) and sloping side walls (40) defining a front channel (36), and said sloping side walls (20) of said first portion (16) are joined to said sloping side walls (40) of said second portion (36), whereby said second box structure (42) is of generally hexagonal shape.

Inventors: GRAY JOHN, KELMAN JOSH, MARION DENNIS, RIBICK JOHN, GRAY, JOHN, KELMAN, JOSH, MARION, DENNIS, RIBICK, JOHN
Applicants: DAVIDSON TEXTRON INC, DAVIDSON TEXTRON INC.
Application year: 1995
Main classification: B60R21
IPC codes: B60R21, B60K37