Self-adjusting knee bolster

Abstract: A knee bolster (10) for protecting the passengers of a motor vehicle comprises one or more deformable members (14) positioned generally forward of each vehicle passenger; ultrasonic sensors (26) for determining the position of the knees and tibiae of each passenger within the motor vehicle relative to the deformable members; and means (20) responsive to the sensing means for articulating and translating each deformable member (14) relative to the vehicle interior and, hence, relative to the knees and tibiae of each passenger corresponding thereto to provide optimum protection to the passengers in the event of a subsequent collision or marked vehicle deceleration.

Description: BACKGROUND OF THE INVENTION The instant invention relates generally to a motor vehicle's interior structure and the use thereof to mitigate injury to vehicle passengers upon collision or marked deceleration of the vehicle. Known knee bolsters comprise deformable elements which are fixedly located about the passenger compartment of a vehicle so as to be positioned opposite the knee and tibia of each vehicle passenger when the passenger is normally seated in the vehicle. See, e.g., U. S. Patent No. 3,947,056 issued March 30, 1976. to Schwanz. Upon a collision or marked deceleration of the vehicle, such knee bolsters collapse in a controlled manner to absorb a portion of the kinetic energy of the vehicle passenger to slow same, thereby reducing the severity of passenger injuries sustained during the event. Significantly, the position and angle of such fixed knee bolsters in relation to the knees and tibiae of each passenger at the time of collision or marked vehicle deceleration have a major effect of the stresses applied to the limbs of the passenger and, hence, the potential for injury. Since such fixed knee bolsters are optimized for passengers of average size, the protection afforded by such knee bolsters becomes increasingly unavailing to passengers whose size deviates from the norm. For example, a 5th percentile female will typically slide under the knee bolster, while a 95th percentile male is likely to suffer substantial injury from knee contact with irregularly shaped dashboard contours and/or vehicular controls situated above the knee bolster. Moreover, such fixed knee bolsters fail to accommodate even an average-sized passenger 1) when the passenger places his feet so as to cause the angle formed between the surface of the knee bolster and either of his tibiae to deviate from the ideal angle to be formed therebetween; 2) when the passenger shifts either of his legs to cause the spacing between the surface of the knee bolster and his tibiae to deviate from the ideal spacing therebetween; or 3) when the passenger shifts his legs so as to raise either of his knees above the knee bolster. The prior art further teaches the use of knee bolsters in conjunction with an active passenger restraint, such as an air bag, to further restrict the passenger's movement relative to such other restraint, such as to prevent the "submarining" of the passenger beneath the air bag during a crash condition. In this manner, the effectiveness of the active restraint in preventing the serious injury to vehicle passengers is significantly increased. Such auxiliary knee bolsters typically comprise a secondary air bag deployable to engage the knees of the vehicle occupant prior to, or simultaneous with, deployment of the primary (torso) bag. See, e.g., U. S. Patent No. 3,768,830 issued October 30, 1973 to Hass, teaching a secondary air bag deployed to engage the knees of the vehicle occupant prior to deployment of the primary air bag; and U. S. Patent No. 3,767,225 issued October 23, 1973 to Maselsky, teaching a knee bolster comprising a bag-within-a-bag positioned opposite the knees of the vehicle occupants and inflated simultaneously therewith. Alternatively, U. S. Patent No. 4,198,075 issued April 15, 1980 to Kob et al. teaches a deformable knee impact plate which is pivotally deployed into a position near the knees of the passenger as by an air bag or belt tensioner upon the detection of a crash condition by suitable sensor means. Unfortunately, as with the fixed knee bolsters discussed hereinabove, such auxiliary knee bolsters are optimized for passengers of average size and present similarly increased likelihood of passenger injury when the passengers legs are shifted from their ideal position relative to the knee bolster prior to the deployment thereof upon the detection of a crash condition. What is needed is a self-adjusting knee bolster whose position within the vehicle relative to the knees and tibiae of a passenger therein continuously adjusts to provide the passenger optimum protection against injury in the event of a subsequent collision or marked vehicle deceleration. DE-A-2537212, on which the precharacterising portion of appended claim 1 is based, discloses a knee bolster for the passenger of a vehicle, the knee bolster being pneumatically moveable towards the passenger and having a valve which is operated by contact with the passenger's knee. It is an object of the instant invention to provide a knee bolster for a motor vehicle which adjusts its position relative to the knees and tibiae of vehicle passengers prior to the detection of a vehicle collision or marked vehicle deceleration, whereby passengers of varying size are each afforded optimal protection against injury during such collision or marked vehicle deceleration. According to the present invention there is provided a safety device for protecting a passenger of a motor vehicle in the event of a rapid deceleration of said motor vehicle comprising: a deformable, force-absorbing member forming an interior surface of said motor vehicle generally forward of a tibia and a knee of said passenger when said passenger is normally seated in said motor vehicle; sensing means for sensing the position of the tibia of said passenger relative to said deformable member; and positioning means responsive to said sensing means for adjusting the position of said deformable member in the lengthwise direction of said vehicle prior to rapid deceleration of said motor vehicle wherein in use the position of said deformable member is adjusted relative to said passenger so as to maintain said deformable member at a substantially constant distance from the tibia of said passenger; characterised in that said positioning means in use further adjusts the position of said deformable member so as to maintain said deformable member in a substantially parallel relationship with the tibia of said passenger. Thus, there may be provided a knee bolster for a motor vehicle which periodically adjusts its position relative to the knees and tibia of vehicle passengers prior to the detection of a vehicle collision or marked vehicle deceleration, whereby passengers are afforded optimal protection against injury during such collision or marked vehicle deceleration notwithstanding periodic shifting of the position of their legs relative the vehicle's interior. A knee bolster according to the present invention may comprise a number of said deformable, force-absorbing members forming interior surfaces of the motor vehicle and the sensing means may be for sensing the position of the passenger's knees and tibia relative to the deformable members respectively so that the positioning means may adjust the position of each deformable member relative to a fixed point on the motor vehicle so as to adjust its position relative to the passenger's knees and tibia in order to minimize passenger injury in the event of a subsequent vehicle collision or marked vehicle deceleration. Furthermore, the position of each deformable member is preferably periodically adjusted so as to maintain its operative surface in a substantially parallel relationship with one of the passenger's tibia at a substantially constant distance therefrom notwithstanding periodic shifting by the passenger of the position of his leg(s) within the vehicle. The means for positioning the deformable member relative to a fixed point on the vehicle and, hence, relative to the vehicle passenger to be protected therewith may comprise one or more actuators extending between the deformable member and a rigid support therefor on the vehicle and these actuators may be operated pneumatically. Alternatively one or more motorized leadscrews or worm drives may extend between the deformable members and a rigid vehicle structures to support and adjust the position of the former within the vehicle. The means for positioning the deformable member may also provided for the raising and lowering of the deformable member relative to other fixed structures within the vehicle, e.g., the vehicle dashboard, and, hence, the knee of the passenger to be protected therewith. Thus there may be provided a knee bolster whose position within a motor vehicle is periodically adjusted so as to 1) maintain its operative surface in a substantially parallel relationship with, and at a substantially constant distance from, the tibia of a passenger's leg; and 2) maintain a portion of its operative surface at a height within the vehicle above the passenger's knee. The means for positioning the deformable member may further comprise a rigid frame supported by the actuators. The frame may have a first track thereon which is in interlocking engagement with a second, complementary track on the deformable member. A rack-and-pinion or worm drip may operate to displace the deformable member relative to the frame along the tracks thereof, whereby the optimal vertical positioning of the deformable element relative to the knee of the passenger is readily prescribed. Where desired, the knee bolster of the instant invention may further comprise a vehicle ignition sensor for determining the operative condition of the vehicle. The positioning means may then respond to the ignition sensor to move the deformable member away from the passenger;s legs to facilitate ingress and egress from the vehicle. Additionally, signal means responsive to the passenger sensing means may be included for providing an audible or visual warning when the passenger assumes a position within the vehicle likely to result in increased injury in the event of a subsequent collision or marked deceleration of the vehicle. The invention will be more clearly understood from the following description given by way of example only with reference to the accompanying drawings in which: FIG. 1 is a schematic, partial side elevational view of a passenger motor vehicle incorporating pneumatically-actuated knee bolsters in accordance with the instant invention; FIG. 2 is a schematic, partial top view of the knee bolsters shown in FIG. 1 along line 2-2 thereof; FIG. 3 is a schematic, partial side elevational view of a motor vehicle incorporating leadscrew-actuated knee bolsters in accordance with the instant invention; FIG. 4 is an isolated side view in elevation of a deformable member supported by an articulated frame via complementary, interlocking tracks and employing a rack-and-pinion drive to enable vertical adjustment of the deformable member relative to the vehicle interior and, hence, the knee and tibia of a passenger's leg to be protected therewith; and FIG. 5 is a cross-sectional view of the deformable member and its supporting frame along line 5-5 of FIG. 4. A first exemplary embodiment 10 of the instant knee bolster for protecting a passenger (not shown) of a motor vehicle 12 against injury in the event of a subsequent collision or marked deceleration of the vehicle 12 is shown schematically in FIGS. 1 and 2. The knee bolster 10 generally comprises a deformable, energy-absorbing member 14 forming an interior surface 16 of the vehicle 12 generally forward of the passenger when he is normally seated on passenger seat 18 therein. The deformable member 14 is supported by pneumatic actuators 20, such as air bladders controlled by suitable sources of pressurized air, extending between the deformable member 14 and rigid supports 22 therefor on the vehicle 12. The pneumatic actuators 20 permit the articulation and substantially horizontal translation of the deformable member 14 relative to other fixed structures within the vehicle, such as the dashboard 24 and seats 18 therein, and, hence, relative to the knees and tibiae of the passenger seated within the vehicle 12. An array of sensors 26 comprising, for example, ultrasonic transmitters and detectors is imbedded in the surface 16 of each deformable member 14. The sensors 26 detect the separational distance between the surface 16 of each deformable member 14 and the upper and lower portions of the tibia of the passenger's leg in opposition therewith. The sensors 26 further detect the relative position of the passenger's knees within the vehicle 12 with respect to the surfaces 16 of each deformable member 14, for the purpose to be more fully described hereinbelow. The sensors 26 provide controlling inputs to the actuators 20, whereupon the actuators 20 position the deformable members 14 within the vehicle 12 so as to achieve the optimal separational distance between the deformable members 14 and the passenger's tibiae notwithstanding periodic movement of the passenger's legs within the vehicle 12 during the normal operation thereof. The optimal separational distance between the surface 16 of the deformable member 14 and the tibiae of the passenger is presently thought to be about 10 cm, with the surface 16 of the deformable member 14 being maintained in a substantially parallel relationship with the passenger's tibia. For example, empirical evidence suggests that ankle injuries are likely to result from a spacing greater than 10 cm due to the ankle rotation allowed thereby. It is noted that, under the instant invention, the deformation experienced by the deformable member 14 during a collision or marked vehicle deceleration can be either of an elastic or plastic nature, or both. The operative surface 16 of each deformable member 14 is preferably provided with a plurality of projections 28 which serve to guide the passenger's knee and tibia thereinto during a collision or marked vehicle deceleration, in the manner known to those skilled in the art. Vehicle structures 30 defining other interior surfaces 32 within the vehicle proximate with the deformable members 14 serve to restrain the movement of the deformable members 14 upon the impingement of the passenger's legs thereupon during a collision or marked vehicle deceleration. Additionally, such proximate interior surfaces 32 may themselves be comprised of force-absorbing materials to provide an additional measure of protection to a passenger whose position within the vehicle is such that the deformable member 14 cannot be articulated and/or translated by the actuators 20 so as to be placed in its optimal position relative to the passenger's leg. In accordance with another feature of the instant invention, a signal lamp (not shown) is illuminated when the sensors 26 determine that the passenger has assumed a position within the vehicle 12 likely to result in increased injury in the event of a subsequent collision or marked deceleration of the vehicle. The passenger is thus warned that he has assumed a position involving greater risk of injury should an accident occur, and the passenger is afforded the opportunity to reposition himself within the vehicle 12 prior to the occurrence of a collision or marked vehicle deceleration. It is further noted that the pneumatic actuators 20 shown in FIGS. 1 and 2 may further serve to absorb a portion of the passenger's kinetic energy during a collision or marked vehicle deceleration. Moreover, a control module (not shown) for the pneumatic actuators 20 may further act to vary the spring rate and damping characteristics thereof as by adjusting the rate of air being bled from the actuators 20 during a crash event, whereby the passengers are afforded even greater protection against bodily injury. In the alternate embodiment 34 of the instant knee bolster illustrated in FIG. 3, the pneumatic actuators 20 of the first embodiment 10 are replaced with actuators 36 comprising a pair of leadscrews 38 pivotally connected with the deformable member 14; a pair of gearnuts 40 mounted on rigid vehicle support 22 and engageable with the leadscrews 38, respectively; and a pair of motors 42 mounted on the vehicle 12 that are responsive to the sensors 26 and operative to selectively turn the gearnuts 40 via flexible shafts 44. Such "worm drives" and suitable control circuits therefor are well known in the art, e.g., for use in articulated seats and, as such, are not further described herein. FIGS. 4 and 5 are isolated views of a deformable member 14 supported by a rigid, articulated frame 46. Specifically, the frame 46 is supported by, and articulated and horizontally translated relative to a fixed point on the vehicle by, a suitable number of pneumatic actuators 20 or worm-drives 36. A pair of complementary, interlocking guide rails or tracks 48 and 50 are provided on the frame 46 and the deformable member 14, respectively, to permit the generally vertical displacement of the deformable member 14 relative to the frame 46. Precise vertical displacement of the deformable member 14 relative to the frame 46 is obtained with a motor-driven rack-and-pinion gear train 52 comprising a motor 54 mounted on the frame 46 which operates to turn a pinion gear 56 engaging a rack gear 58 mounted on the deformable member 14. The gear train 52 operates under the control of the sensors 26 so as to maintain a portion of the operative surface 16 of each deformable member 14 at a height within the vehicle 12 above the passenger's knee to be protected therewith. In this manner, the instant knee bolster ensures the protection of those passengers whose size deviates from the norm or whose leg movements would otherwise render the protection afforded by known fixed knee bolsters unavailing. In accordance with another feature of the instant invention, a vehicle ignition sensor (not shown) determines the operative condition of the vehicle. The pneumatic actuators 20/worm drives 36 and vertical-positioning motor 54 respond to the ignition sensor to move the deformable member 14 away from the passenger's legs to facilitate ingress and egress from the vehicle 12. While the preferred embodiment of the invention has been disclosed, it should be appreciated that the invention is susceptible of modification without departing from the scope of the subjoined claims. For example, the instant invention contemplates the use of sensors for detecting the passenger's weight, the position of the passenger's seat, the location of the passenger's feet on the floor of the vehicle, etc., as may be required in order to optimally deploy the deformable member of the instant knee bolster prior to a collision or marked vehicle deceleration. Similarly, suitable transducers may be employed to monitor the instantaneous position of the deformable member within the vehicle relative to the rigid supports therefor, as through the use of Hall-effect transducers in combination with the worm drives shown in FIGS. 3 and 5, thereby permitting the installation of the sensors on fixed structures within the vehicle rather than imbedding them in the surface of the deformable member, as described hereinabove.

Claims: A safety device for protecting a passenger of a motor vehicle (12) in the event of a rapid deceleration of said motor vehicle (12) comprising: a deformable, force-absorbing member (14) forming an interior surface (16) of said motor vehicle (12) generally forward of a tibia and a knee of said passenger when said passenger is normally seated in said motor vehicle (12); sensing means (26) for sensing the position of the tibia of said passenger relative to said deformable member (14); and positioning means (20) responsive to said sensing means (26) for adjusting the position of said deformable member (14) in the lengthwise direction of said vehicle prior to rapid deceleration of said motor vehicle (12) wherein in use the position of said deformable member (14) is adjusted relative to said passenger so as to maintain said deformable member (14) at a substantially constant distance from the tibia of said passenger; characterised in that said positioning means (20) in use further adjusts the position of said deformable member (14) so as to maintain said deformable member in a substantially parallel relationship with the tibia of said passenger. The safety device of claim 1, wherein the position of said deformable member (14) relative to said passenger is adjusted by said positioning means (20) so as to maintain a portion of the surface of said deformable member (14) at a height within the motor vehicle (12) above the knee of said passenger. The safety device of claim 1 or 2 wherein said positioning means (20) comprises an actuator (20) extending between said deformable member (14) and a rigid support (22) therefor on said motor vehicle (12). The safety device of claim 3 wherein said actuator (20) is operated pneumatically. The safety device of claim 3 wherein said actuator (36) comprises a leadscrew (38); a gearnut (40) mounted on said motor vehicle (12) and engageable with said leadscrew (38); and a motor (42) operative to turn said gearnut (40), whereby said leadscrew (38) is advanced in said gearnut (40) upon operation of said motor (42). The safety device of claim 3, 4 or 5 wherein said positioning means (20) for articulation and translating said deformable member (14) further comprises a frame (46) supported by said actuator (20,36); and means on said frame (46) for supporting said deformable member (14) with respect thereto. The safety device of claim 6 wherein said means on said frame for supporting said deformable member (14) comprises a first track (48) on said frame (46); a second track (50) on said deformable element (14) complementary with the first track (48) on said frame (46) and in interlocking engagement therewith; and means (52) operative to displace said deformable element (14) relative to said frame (46) along the first track (48) thereof. The safety device of claim 7 wherein said means (52) operative to displace said deformable element (14) relative to said frame along the first track thereof comprises a rack-and-pinion gear train (52); and a motor (54) operative to turn said pinion gear (56) of said gear train (52). The safety device of any preceding claim including vehicle ignition sensing means for determining the operative condition of said motor vehicle (12); and wherein said positioning means (20) responds to said ignition sensing means to move said deformable member (14) away from said passenger to facilitate ingress and egress from said vehicle (12). The safety device of any preceding claim wherein said passenger sensing means (26) comprises an ultrasonic transmitter and an ultrasonic detector. The safety device of any preceding claim including signal means responsive to said passenger sensing means for warning said passenger when said passenger assumes a position within said vehicle (12) likely to result in increased injury to said passenger in the event of a subsequent collision or marked deceleration of said motor vehicle (12).

Inventors: BEHR LEONARD W, WHITE CRAIG W, BEHR, LEONARD W., WHITE, CRAIG W.
Applicants: AUTOMOTIVE SYSTEMS LAB, AUTOMOTIVE SYSTEMS LABORATORY INC.
Application year: 1990
Main classification: B60R21
IPC codes: B60R21, F16F7, G01S15