Chairs and seats – Crash seat – Force-absorbing means incorporated into back
Reexamination Certificate
2000-03-01
2001-10-02
Cuomo, Peter M. (Department: 3636)
Chairs and seats
Crash seat
Force-absorbing means incorporated into back
C297S216130, C297S362110, C297S378110
Reexamination Certificate
active
06296306
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a vehicle seat with an adjustable backrest.
BACKGROUND OF THE INVENTION
It is known to adjust the angle of inclination of the backrest using a hand wheel or an electric motor. A rotational movement produced in this way is transmitted to the backrest via a step-down gear that is formed by a wobble mechanism in most cases.
With conventional vehicle seats there is the risk in the event of a rear end collision, owing to the relatively pronounced flexibility of the backrest cushioning for comfort requirements, that the vehicle occupant will slide up along the backrest. In particular, if the headrest is adjusted too low, the headrest acts only as a slight restraint, resulting in over-stretching of the back of the neck and excessive straining of the back of the neck and resultant injuries to the cervical vertebra.
SUMMARY OF THE INVENTION
There is provided in accordance with the present invention a vehicle seat wherein the restraint function is improved in the event of a rear end collision with a trailing vehicle. The backrest is inclined forwardly in the event of a rear end collision or on the response of a pre-crash sensor. At the same time, the headrest can be moved upwardly and/or forwardly. A corresponding drive acts on the rigid backrest frame. The flexibility of the backrest cushioning allows forward adjustment of the backrest. This ensures that the backrest is brought into an upright position or in the direction of an upright position and optionally additionally forwardly and that continuous contact with the vehicle occupant's back exists in the backrest region. The upward and/or forward adjustment of the headrest also ensures that the occupant's head makes early contact with the headrest. The prerequisite whereby the vehicle occupant's body remains fixed on the vehicle seat in the event of a rear end collision is satisfied. The risks of injury existing with known vehicle seats are considerably reduced.
Furthermore, an energy absorber is connected to the backrest via an associated separate guide means after the forwardly directed adjustment of the backrest. An opposing, rearwards movement of the backrest following the forward adjustment is decelerated by the energy absorber. This rearwards directed movement of the backrest is due to the correspondingly directed movement of the vehicle occupant in relation to the vehicle seat during the rebound phase. Owing to the reduction of the gear acting on the backrest adjustment, no rearward adjustment of the backrest in relation to the seat surface is possible if force is introduced outwardly from the rigid backrest frame into the gear. The unit formed by joint and gear, which can form a backrest-adjusting device, acts as a rigid connection. The coupling of the energy absorber allows a decelerated rearward movement of the backrest. The energy absorber co-operates with the guide device, for example a link guide or a different guide device provided on the seat substructure. The energy absorber can be a rigid axis around which the backrest is pivoted forward in normal operation for convenient boarding in the back of the vehicle or an axis provided on the seat substructure or a joint which comes into effect during adjustment of the seat height or fulfils other functions in normal operation. Excessive forces of inertia resulting from the body weight of the vehicle occupant in the event of a rear end collision are reduced by the energy-absorbing action. The energy absorber acts as a load limiter.
An electric motor, in particular a brushless or collectorless d.c. motor having a rotor comprising permanent magnets as poles, is suitable as a driving device. A motor of this type is known, for example, from DE 43 02 042 A1. The stator of the electric motor is supported on the seat substructure, or vehicle body, by an intermediate carrier. The rotor acts with its output shaft on the input side of the backrest-adjusting device. As already explained, the backrest is secured in the respective angular position by rotational self-locking owing to the gear reduction acting in or on the backrest adjustment device.
The forward inclination caused by the rear end collision or the pre-crash sensor by the thus activated driving device can be effected around the joint, in particular a pivot joint around which the backrest is pivoted relative to the seat surface even with conventional backrest adjustment. The output side of the reduction (step-down) gear in this case, is a component of the joint, in particular the pivot joint. During the decelerated opposing rearward movement of the backrest, the backrest is guided on the guide device supported on the vehicle body by the backrest-adjusting device that behaves rigidly owing to the rotational self-locking. For this purpose, the guide device can be supported on the vehicle body by the rigid seat substructure.
The headrest can also be adjusted by the driving device. For this purpose, the driving device, for example via a pulling means optionally adapted to be coupled to a rotating part of the backrest-adjusting device, can release an energy store having a mechanical, pyrotechnic or other design. The adjustable headrest can be designed, for example, as known from DE 197 06 290 A1. A separate energy store for activation in the event of a rear end collision can also be provided.
Advantageously, the energy supply to the driving device, in particular the power supply to the electric motor, is interrupted in such a way that it can no longer be switched on after energy absorption has been activated, i.e. after the rearward movement of the backrest has been decelerated.
The backrest-adjusting device and/or the driving device for backrest adjustment can be provided on both sides of the backrest.
In a preferred manner, the electric motor driving device which is used both during backrest adjustment in normal driving mode and during backrest adjustment in the event of a rear end collision can preferably be a flat motor designed as a brushless or collectorless flat motor of the type described, for example, in DE 43 02 042 A1. An electric motor of this type possesses stator poles that are located on an internal radius, and rotor poles that are arranged around a common axis on an external radius. The axial span of the unit containing the rotor and the stator is substantially smaller in size than the external diameter of the rotor. The stator poles are formed by field windings arranged around laminated poles. The stator carrier is supported in a fixed manner on the motor housing and on the vehicle body, in particular on the seat substructure. It can also comprise a ring gear for a step-down gear, in particular planetary gear, on its internal face. For this purpose, the ring gear can be formed integrally with the stator carrier and exist in the form of internal teeth on the stator carrier. The rotor can be bell-shaped in design and, in the region of its rotor casing, can serve as a carrier for the rotor poles that are preferably designed as permanent magnets.
The driving device can be coupled to the energy absorber for controlled energy absorption during rearward displacement of the backrest in a rear end collision. The desired energy absorption can be adjusted depending on the weight of the vehicle occupant or also depending on a distance measurement per unit of time during backrest adjustment in the crash phase. It is also possible to bring about the desired energy absorption merely by means of the driving device. The electric motor is controlled accordingly for this purpose.
The driving device can also be activated in normal driving mode in order to adjust the backrest forwardly. For example, a convenient adjustment for climbing into the back of two-door vehicles can thus be achieved. At the same time, a retraction of the headrest can be effected by a coupling device, for example in the form of a control cable (Bowden cable) assembly, during the forward pivoting of the backrest. The headrest is brought back into the previous extended position by a memory function whe
Meyer Rudolf
Specht Martin
Breed Automotive Technology Inc.
Cuomo Peter M.
Drayer Lonnie R.
Edell Joseph
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