Chairs and seats – Crash seat – Force-absorbing means incorporated into headrest area
Reexamination Certificate
2001-08-23
2004-11-30
Barfield, Anthony D. (Department: 3636)
Chairs and seats
Crash seat
Force-absorbing means incorporated into headrest area
C297S408000, C297S216130
Reexamination Certificate
active
06824212
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a vehicle seat including a clamshell-shaped head restraint with a front part which is movable relative to a rear part in response to a control signal.
2. Background Art
Serious attention has been given for decades to increasing the passive safety in the design of motor vehicles, in particular passenger cars. In addition to endeavors to use CAD techniques for optimizing the entire vehicle structure so as to improve the crash behavior, emphasis has been given to measures for increasing the safety of the occupants in the interior. One result of this development involves complicated and extremely effective restraint systems using various air bags and seat belt tighteners.
A further result, although one which has aroused less public attention, of the endeavors for a design of the interior which is optimized with regard to occupant safety involves solutions for optimizing the position of parts of the seat structure, in particular of the head restraint part, in a frontal or rear-end impact. One solution of this type which has been introduced in practice is the “pro-tech” system from EP 0 627 340 A1.
In the conventional system, in a rear-end impact the head restraint part is pivoted towards the driver's head so as to counteract the dreaded “whiplash”. The head restraint adjustment is brought about via a complicated and costly lever mechanism and via a compression plate in the backrest, which compression plate is acted upon by the driver's body.
In this case, head restraints, at least of the front seats, have been designed such that they are height-adjustable, in order to provide vehicle occupants of different height an optimally positioned bearing surface in each case for the back of the head in the event of a frontal impact. At the same time, the height-adjustability also constitutes an element of comfort, since even during normal driving many drivers prefer a posture with the back of their head leaning against the head restraint. Recently, head restraints which are even height-adjustable electrically are being offered in high-cost passenger cars.
In the last few years, head restraints having an adjustable inclination have also become established—at least as an option—in passenger cars of the upper class and upper middle class. These head restraints provide further improvement in the ability to set the head restraint to match the anatomy and preferred posture of the vehicle occupant. In the known arrangements, the inclination is adjusted manually.
All in all, vehicle seats having height-and inclination-adjustable head restraints—in particular those with electric height adjustment—have a complicated structure and are therefore expensive even before they are able to satisfy all of the safety requirements and demands for comfort. In particular, an adjustment of the inclination while under way is possible only with difficulty, if at all.
SUMMARY OF THE INVENTION
The invention is therefore based on the object of specifying a vehicle seat which is improved in respect of the functioning and design of the head restraint and is distinguished by a simple construction with reliable functioning and simple operability.
This object is achieved by a vehicle seat including a clamshell-shaped head restraint with a front part which is movable relative to a rear part in response to a control signal.
The invention includes the basic concept of providing a two-part head restraint which as such is known and has a pivotable front part with a suitable driving device for pivoting it forwards in the event of a vehicle impact, and of equipping a vehicle seat with this combined arrangement. Furthermore, the invention includes the concept of realizing a non-manual adjustment of the inclination in an expedient manner on the basis of the two-part head restraint construction. A head restraint of this type is suitable for equipping with a motor-powered or hydraulic driving device, particularly since the rigid head restraint rear part conveniently provides a supporting surface not only for the actual adjustment, but also when the head restraint front part (and therefore the driver) is subjected to great momentum as a consequence of a vehicle impact.
In a design which can be realized in a structurally particularly useful manner, a mechanical actuator or control signal transmitter is provided which detects the acceleration imparted in the vehicle impact to a vehicle occupant and derives from this the control signal and at the same time the driving force for driving the head restraint front part. In the very simplest case, this mechanical transmitter has a compression plate which is arranged in the backrest and can be moved with respect to an essentially rigid backrest frame in the direction of travel by a movement component.
However, a design which is preferred from the current point of view includes the recognition that the vehicle occupant's body which is usable as the “driving source” and in the event of an impact experiences an acceleration and exerts a force on the vehicle seat, in particular on the backrest, does indeed act upon the backrest with a great force, but can only cover a relatively small distance therein. This is due to the fact that the space utilization in modern motor vehicles is optimized even by doing without backrest construction depths which are not absolutely required. In this case, most of the construction depth or thickness of a backrest has to be available for movements of the vehicle occupant in the upholstery with little contact-pressure force, i.e. so as to ensure an appropriate seat comfort.
This recognition results in the further concept of providing a driving or force-transmitting device for adjustment in the event of a crash, which device obtains an enlarged adjustment path from the displacement of the vehicle occupant over a short distance (under the effect of the load of the ultimately available driving force). Ultimately, the preferred design includes the concept of realizing this basic idea by co-ordinating primary and secondary tension elements which are driven by the displacement of a movable body (specifically, the vehicle occupant's body), in which case the abovementioned extension of the adjustment path is obtained by the primary tension elements causing a zigzag or meandering deformation of the secondary tension element.
In one specific refinement, the primary tension elements are designed as essentially inextensible wires or threads or strips running transversely or obliquely with respect to the direction of displacement of the vehicle occupant and with respect to the longitudinal axis of the secondary tension element. In particular, the essentially perpendicular arrangement with respect to one another of the direction of displacement of the vehicle occupant's body, of the longitudinal axis of the secondary tension element and of the longitudinal extensions of the primary tension elements ensures an optimum force/path conversion and therefore advantageous functions of the driving device.
In a first refinement of this design, which, in principle, is preferred, the wires or strips which are used as the primary tension elements loop around the secondary tension element and are fastened by both ends to the basic bodyspecifically, to the vehicle seat frame. In this case, the two ends are fastened to points on the basic body which are either closely adjacent to one another or else at a greater distance from one another.
In an alternative refinement to this, the wires or strips are fastened by one end in each case to the basic body and have at the free end a hook or a loop with which they grip around the secondary tension element.
In both designs, a certain amount of play can be provided between the respective engagement points of the primary tension elements and the secondary tension element so as to ensure unimpeded movement of the vehicle occupant in the seat upholstery. In another variant, a corresponding amount of play is, however, also provided with regard to the adjustm
Fischer Harald
Malsch Heiko
Barfield Anthony D.
Lear Corporation
Panagos Bill C.
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