Abstract:
An automobile which affords increased safety to its occupants and sustains minimal damage during a frontal collision includes elongated force-transmitting members that extend between front and rear bumpers in slidably telescopic interaction with the chassis of the automobile. Energy-absorbing springs receive force from a rearwardly displaced rear bumper during a frontal collision, and impart a rearward pulling effect on the automobile.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to systems for minimizing damage to an automobile and injury to its occupants in a frontal collision, and more particularly concerns automotive vehicles having front energy-absorbing means and a movable passenger compartment. 
     2. Description of the Prior Art 
     U.S. Pat. Nos. 3,508,783; 3,695,629; 3,589,466; 5,738,373; 3,806,184; 3,743,347 and 3,479,080 describe passenger compartments which, upon frontal impact, slide forwardly and upwardly. Such movement protects the occupant from injury by providing a longer effective stopping distance and causing the occupant&#39;s body to assume a semisupine position which can more effectively cope with impact force. None of these patents, however, provide means for making the vehicle itself particularly less damageable. 
     U.S. Pat. No. 3,848,886 describes an impact-absorbing frame system with telescoping bumper mounts and a frame equipped with energy absorbing sections which collapse on impact. Again, this does not make the vehicle itself particularly less damageable. 
     U.S. Pat. No. 4,232,755 describes an electric motor vehicle divisible into separable front, middle and rear sections. The middle section includes a passenger compartment that slides fore and aft in a collision. However, the compartment does not tilt the passenger to a protective semisupine position. Aside from the telescoping bumper mounts it has no further means for minimizing collision damage. 
     U.S. Pat. No. 3,476,434 describes an automotive vehicle having a shock mounted passenger-carrying area which is free to move horizontally, whereby deceleration forces on the passengers are dissipated more slowly. It has no means for making the vehicle less damageable. 
     U.S. Pat. No. 3,560,041 describes a driver/passenger compartment mounted on a separate chassis, with shock-absorbing means between them. It describes extensive interior padding to protect the occupants from head to foot but has no means for making the vehicle less damageable. 
     U.S. Pat. Nos. 5,941,582; 5,884,959 and 4,441,751 describe various means for improving the impact-absorbing capacity of front bumper assemblies. The impact force of the collision is thus ultimately transmitted to the frame. There are no provisions for making the frame itself less prone to damage from this force. 
     U.S. Pat. No. 5,451,077 describes a resilient safety bumper and a two-piece frame. The bumper partially absorbs the impact, and the front section of the frame swivels sideways to further protect the passenger-carrying rear section from impact shock. It has no means for making the vehicle as a whole less damageable. 
     In U.S. Pat. Nos. 4,192,538; 4,411,462; 4,518,183 and 4,176,858, the bumper assembly utilizes an air container means such as an air bag to improve its impact-absorbing capacity. The bumper assembly is mounted to the adjacent portion of the vehicular frame, to which the impact force of the collision, albeit dampened, is ultimately transmitted. They do not include means for making the frame itself less deformable or less damageable. 
     U.S. Pat. No. 4,065,169 describes an energy transforming means which allows an upward movement of a truck&#39;s rear body, exclusive of the passenger compartment, to absorb kinetic energy of the body upon collision. It does not describe a separate passenger compartment slidably mounted on the chassis and does not describe means for making the vehicle less damageable. 
     It is evident from the above that although many patents address the problem of passenger safety and address the matter of improving the impact-absorbing capacity of the bumper assembly, none of them present means for making the vehicle itself less damageable, particularly its frame or chassis. It is well known that a bent frame or chassis is frequently the reason for declaring the vehicle a total loss. 
     SUMMARY OF THE INVENTION 
     It is accordingly the primary object of this invention to provide a vehicle that is not only safer for its occupants during a frontal collision but also one that is less damageable. It achieves this by a novel approach based on the observation that a hollow body in motion such as an automobile whose structural integrity is maintained by a deformable framework is more apt to sustain damage and deformity if its motion is halted by a compressive force applied to its leading aspect (“a push from the front”) than if its motion is stopped by an equal traction force acting on its rear aspect (“a pull from behind”). This is because in general the materials used in automobiles such as the chassis is more apt to be bent when pushed from the front end than when pulled (to a stop) from the rear end, other factors being equal. That is, they are better able to withstand tensile stress than compressive or bending stress. 
     The novel approach used in this invention is the means for instantaneous transfer of the impact force from the front bumper to the rear bumper, making it possible to use the rear bumper as a strong anchor from which to exert a strong controlled traction force (“pull from behind”) on the chassis and thereby gradually pull the chassis and the rest of the vehicle to a controlled stop. 
     Another purpose of this invention is to reduce the cost of manufacture by using standard off-the-shelf parts such as the illustrated leaf springs and shock absorbers, and straight tubular members for the chassis and bumper supports which are not only inexpensive to fabricate but are also less apt to be deformed when subjected to strong axially directed forces like those that occur during frontal collisions. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     With these and other advantages in view, the invention is disclosed in the following description which will be more fully understood when it is read in conjunction with the accompanying drawings in which: 
     FIG. 1 is a top view, partially in section, of an automotive vehicle having an embodiment of the protective system of this invention. 
     FIG. 2 is a horizontal sectional view of the embodiment of FIG.  2 . 
     FIG. 3 is a view similar to FIG. 7, showing the state of the vehicle during a head-on collision. 
     FIG. 4 is a sectional view taken along line  4 — 4  of FIG.  1 . 
     FIG. 5 is a sectional view taken along line  5 — 5  of FIG.  1 . 
     FIG. 6 is a sectional view taken along line  6 — 6  of FIG.  1 . 
    
    
     For clarity of illustration, details which are not relevant to the invention, such as the engine, power train, internal air bags, etc., have been omitted from the aforesaid drawings. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the above drawings wherein one character designates one part of the vehicle, there is shown an automobile  1 , with chassis  2  and passenger module  3 . Supporting the chassis  2  are wheels  4  journaled to axles  5  attached to springs  6  which are anchored to chassis  2  by front leading hangers  7 , front trailing hangers  8 , rear leading hangers  9 , and rear trailing hangers  10 . 
     The chassis  2  is composed of left tubular longitudinal member  11  and right tubular longitudinal member  12  which are fixedly attached to each other by front cross member  13 , second cross member  14 , third cross member  15  and rear cross member  16 , forming a rigid “ladder” configuration. 
     Snugly but movably fitted inside left tubular longitudinal member  11  is left tubular bumper support  17 , and similarly mounted inside right tubular longitudinal member  12  is right tubular bumper support  18 ; said fit being snug enough to prevent rattling, but loose enough to permit forward and backward movement of the bumper supports  17  and  18  within the members  11  and  12 . Lubrication with grease facilitates such movement. 
     The front bumper is attached to the bumper supports  17  and  18  by hinges  20  and  21  which allow hinge motion-on a horizontal axis but not on a vertical axis. The hinges  20  and  21  are movably attached to bumper  19  in a manner that allows lateral sliding motion of hinges  20  and  21  relative to bumper  19 . Hinge stopper  22  attached to bumper  19  prevents hinges  20  and  21  from being moved towards each other during a collision. 
     A prestressed cable  23  anchors right hinge  21  to the left end of front cross member  13 , and a similar cable  24  anchors left hinge  20  to the right end of front cross member  13 . Said cables prevent sideward displacement of front bumper  19  and sideward bending deformity of tubular bumper supports  17  and  18  during an offset frontal collision, yet these cables do not impede the rearward telescoping motion of the bumper supports  17  and  18  through the tubular longitudinal members  11  and  12  of the chassis  2 . 
     The tubular bumper supports  17  and  18  extend substantially forward from the front end of chassis  2  and extend rearward from the rear end of chassis  2  as well. Rear bumper hinges  25  and  26  attach rear bumper  27  to the rear ends of tubular bumper supports  17  and  18  in a manner similar to the hinged attachments of front bumper  19 . 
     Rear bumper leaf spring  28  is fixed to the rear bumper  27  by clamps  29  and  30 ; and rear cross member leaf spring  31  is fixed to the rear cross member  16  by clamps  32  and  33 . Rear bumper leaf spring  28  is movably attached at each end to the corresponding ends of rear cross member leaf spring  31  by U-bolts  34  and straps  35  so that together their spring action controllably restrains rearward movement of rear bumper  27  relative to the chassis  2 . When in their unstressed, resting state, the leaf springs  28  and  31  are pre-loaded so that their ends pull against each other through their linkage with U-bolts  34  and straps  35 , with a force of about 500 to 800 lbs. This preload force is borne by rubber bumper  84 , attached to leaf spring  31 , which stops this force from causing direct contact between leaf spring  28  and rear cross member leaf spring  31 . This arrangement prevents rearward movement of the rear bumper  27  relative to chassis  2  unless it is subjected to a rearward force in excess of the spring preload stated above. 
     During a frontal collision, when the impact force exceeds the spring preload of 500 to 800 lbs., the front bumper  19  is pushed rearward, causing the tubular bumper supports  17  and  18  to telescope rearward within chassis  2  and push rear bumper  27  rearward. This motion is controllably resisted by leaf springs  28  and  31  and dampened by shock absorbers  36  and  37 . This results in a controlled gradual stoppage of the forward motion of chassis  2 . Thus the forward motion of the main mass of the vehicle is stopped through a controlled pull on the chassis from behind rather than by a strong sudden blow from the front which would be more damaging and deforming to the vehicle, particularly the chassis. 
     The passenger module  3  may be constructed as a separate unit, seated on the chassis  2  in a manner that allows it to glide forward and tilt upward during a collision. 
     After the collision, the return action of rear bumper leaf spring  28  and rear cross member leaf spring  31  pulls the rear bumper  27  back to its original position; the rear bumper  27  in turn pushes tubular bumper supports  17  and  18  forward, thus causing them to return front bumper  19  to its original forward position. This return movement is dampened by shock absorbers  36  and  37 . 
     It may be seen from the foregoing description that in addition to providing means for reducing vehicular damage and passenger injury through temporary displacement of certain parts of the vehicle, the invention also provides for automatic return of these parts to their original position. 
     Although this preferred embodiment is described in great detail, it is to be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention which is more fully defined in the appended claims.