Land vehicles: bodies and tops – Bodies – Seats with body modifications
Reexamination Certificate
1999-01-22
2001-02-20
Dayoan, D. Glenn (Department: 3612)
Land vehicles: bodies and tops
Bodies
Seats with body modifications
C297S216180, C297S216190, C297S329000
Reexamination Certificate
active
06189946
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to car safety devices in general and, in particular, to a device and method for reducing rider injuries in the event of a motor vehicle collision.
BACKGROUND OF THE INVENTION
In order to reduce riders' injuries in the event of a motor vehicle collision, two major safety devices have been introduced: the safety belt, and the air bag.
The safety belt prevents riders from being thrown towards the windscreen in the event of collision. This device has proven effective at low urban vehicle speeds. However, when vehicle speed increases towards the interurban speeds, the safety belt itself becomes a source of injuries. Due to the substantial inertia forces exerted on a rider's body, the abdomen and chest can be crushed by the relatively stiff belt, which prevents any relief from high decelerations exerted on the rider's body by energy absorbent displacements.
The introduction of the air bag, as a supplement to the safety belt, was intended to soften the blow from the rider-safety belt operation. Unfortunately, the short time response of the safety belt, due to its relatively high stiffness, versus the deployment time of the air bag (depending, mainly, on gas pressure generated by a pyrotechnic tablet), called for highly accelerating the air bag, to catch up with the safety belt time response, in order to ensure the simultaneous operation of both. Therefore, an extremely high air bag velocity of 320 km/h is needed for the air bag and safety belt to operate simultaneously.
The worrisome number of injuries, caused by air bags fired towards rider's chests and head, revealed the air bag as a new source of a potential hazard. Although the air bag may be considered as a contribution to the total safety of vehicle riders, some inevitable new perceptions of the whole chair, safety belt, and air bag systems must be worked out to overcome the problems which remain unsolved.
A number of solutions to the problem of deceleration forces acting on a rider during a collision have been proposed in the patent literature. For example, there is shown in U.S. Pat. No. 5,244,252 to Serber a seat assembly for a vehicle which includes a seat, a seat back, and mounting means mounting the seat for movement in fore and aft directions in the vehicle along an upwardly concave arcuate path. This seat assembly is designed to prevent “submarining”, wherein the body slides away from the seat, out from under the seatbelt. The arcuate path has a radius of curvature which is sufficiently large to timely move in front of and to contain the person's buttocks so as to reduce deceleration and maintain frictional contact of the person's buttocks with the seat. The seat belt is coupled to the chassis adjacent the seat back, and the seat is not coupled to the seat back, so the effect is to fold the person's body at the waist.
There is shown in WO94/22692 to Muller, a process for reducing the forces acting on a passenger belted into a seat in a vehicle when the vehicle collides with an obstacle. The approach to an obstacle is detected and evaluated by proximity detectors acting as sensors and, when a collision is recognized as inevitable, the seat is accelerated against the collision direction, stopped at the end of its travel and, once the collision has occurred, the seat is moved in the collision direction and stopped at the end of its travel. Preferably, an airbag system is actuated at the same time as the movement of the seat, possibly by the proximity detection system.
This proposal suffers from several disadvantages. First, any proximity detector system is subject to failure or accidental actuation. If the sensor indicates there will be a collision, and there is no collision, the driver or passenger finds himself moving back within the vehicle, which can disrupt his concentration and provide difficulties returning the seat to its former position. Second, if there is not precise time correlation between the movement of the seat and the occurrence of the collision, the seat can be moving backwards at the time of impact. In this case, the forces acting on the person will be much greater than those caused by the impact alone, increasing the likelihood of injury. Third, when a driven sees he is about to crash, he will generally apply the brakes, causing his body to move forward. If he does so while the seat is moving away from the brake pedal, it can prevent effective braking of the vehicle, and also increase deceleration forces acting on his body. In addition, a linear spring is provided to absorb the energy in the piston at stop the seat at the end of its travel. However, due to bottoming, the seat will stop with a bump, in both directions.
There is shown, in Japanese laid-open publication 9-226495 (Mitsubishi), a passenger protection system for a vehicle including a seat movement unit to retreat a seat to a predetermined position on receipt of an air bag start signal. Simultaneously, a seat belt expansion unit expands a chest guard and an abdomen guard on the seat belt, which is attached to the vehicle chassis. In this system, the airbag is inflated upon impact above a threshold, at which time the vehicle seat moves away from the airbag. In this system, like that described above, the movement of the vehicle seat away from the airbag at the time of collision, increases, rather than decreases, the deceleration forces acting on the body.
A similar problem arises in the event of a rear end collision, especially which the vehicle is hit when stationary. In this case, the force of the collision causes the vehicle to accelerate in a forward direction, while the body of a rider moves backwards until it hits the back of the car seat. Due to the acceleration forces acting on the body, and the fact that the head support is generally not located in the ideal position to support the rider's head, a rider in this situation often suffers from whiplash.
Accordingly, there is a long felt need for a motor vehicle safety system which incorporates the operation of air bag and safety belt in such a way to provide maximum protection with minimum injuries from the safety devices themselves. In addition, it would be very desirable to have such a safety system which also provides protection in the event of a rear end collision.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a safety system for a motor vehicle having a chassis, including a vehicle chair mounted on the chassis for slidable and rotational movement relative to the chassis under inertial forces above a pre-selected threshold acting on the seat and rider in the event of vehicle collision. Chest and abdomen safety belts are affixed to the vehicle chair. A spring damper system, capable of undergoing large deformation, couples the vehicle seat to the chassis.
According to a preferred embodiment, the spring damper system is non-linear, whose stiffness and/or damping coefficients grow with displacement.
The movement of the chair relative to the chassis is preferably subject to a constrained trajectory consisting of linear movement which may coincide with or be opposite the direction of vehicle motion, and angular rotation having a non-constant growing radius in the direction opposite to the chair motion. The dynamic response of the slidable chair system results in substantially reduced deceleration (or acceleration, depending upon the direction of the collision) acting on the chair and rider (compared to vehicle input). Moreover, combining the angular rotation aforementioned, with the linear movement, causes the rider's most vulnerable limbs, e.g. head and chest, to undergo the lowest decelerations in the case of a front end collision, accelerations in the case of a rear end collision, velocities and displacements (relative to the chassis). For front end collisions, the dynamic traits of the vehicle chair of the invention enable the air bag to complete its deployment just before the moving chair and rider encounter it. The effective velocity (in terms of air bag in
Dayoan D. Glenn
Engle Patricia
Van Dyke Gardner, Linn & Burkhart, LLP
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