Chairs and seats – Headrest – Adjustable rectilinearly vertically
Reexamination Certificate
2000-12-01
2002-05-21
Barfield, Anthony D. (Department: 3636)
Chairs and seats
Headrest
Adjustable rectilinearly vertically
C297S061000, C297S378120
Reexamination Certificate
active
06390558
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to German Patent Application No. 19957793.5 filed Dec. 1, 1999.
BACKGROUND OF THE INVENTION
The present invention relates to a seat for a means of transport, in particular a vehicle seat, comprising a seat part, a backrest, a backrest adjustment system which connects the backrest to the seat part and which permits a forward pivoting of the backrest onto the seat part, a height adjustable headrest which is displaceably guided via at least one guide rod in an associated guide receiver in the backrest, and retaining means which are effective between at least one guide rod and the associated guide receiver and through which the guide rod is releasably fixable at different heights against displacement.
In two-door motor vehicles, the backrests of the front seats are usually made to pivot forwardly to make it easier to get into the back seats. In vehicles with a low height such as sports cars, the headrest can come into contact with the vehicle roof or the sun visor during this movement. The forward pivoting of the backrest can be made more difficult or even prevented in this way. The set height of the headrest can also be changed.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a seat of the kind initially mentioned in which these problems do not occur and wherein in particular contact between the headrest and the vehicle roof should be avoided during the forward pivoting of the backrest.
This object is satisfied by the guide receiver for the guide rod being formed so as to be retractable together with the guide rod opposite to the extension direction of the headrest inwards into the backrest into a recessed position and back out again while the guide rod is arrested by the retaining means relative to the guide receiver and by means being provided through which an automatic inward movement of the guide receiver is caused by the forward pivoting of the backrest and an automatic outward movement of the guide receiver back into its original position is caused when the backrest is pivoted back.
Due to the automatic inward movement of the guide receiver while the backrest is pivoted forwardly, a low position of the headrest is also achieved when this was previously set to a greater height. Contact of the headrest with the vehicle roof during the forward pivoting of the backrest can thereby be effectively prevented. The headrest can be retracted so far until the headrest contacts the upper side of the backrest, that is possibly further than its lowest setting position in which the headrest still has a small spacing to the upper side of the backrest. The amount the headrest protrudes upwardly over the backrest is thereby reduced to a minimum so that contact with the vehicle roof can also be avoided with very low vehicles. The guide receiver is here also stopped via the retaining means so that the set headrest height does not change.
The inward movement of the guide receiver with the guide rods being held in place by the retaining means with respect to the guide receiver, at the same time ensures that the headrest position does not change relative to the guide receiver during retraction. When the guide receiver is again extended back into its starting position, the previously set headrest position is therefore again reached. Thus, no new setting is required. Nevertheless, the setting capability of the headrest height is maintained without restriction over the whole setting range.
In accordance with an embodiment of the invention, at least one force deflection system having a flexible force transmission element is active between the backrest adjustment system and the guide receiver for the retraction and/or extension of the guide receiver. A Bowden cable can in particular serve to move the guide receiver inwardly and/or outwardly. Such a system requires little construction effort and can be accommodated in the seat in a space-saving manner. Moreover, due to the flexibility of the force transmission element, it allows a combination with an active head rest system in which the headrest is moved from its normal position into a position displaced upwardly and forwardly in the event of a rear-end impact.
The force transmission element preferably acts on the guide receiver in the extension direction while an elastic return device is provided which acts on the guide receiver in the retraction direction. The construction effort is reduced by the use of an elastic return device and the return force is advantageously supported by gravity since the return device acts on the guide receiver in the retraction direction, that is approximately in the direction of gravity. The return element can be given lower dimensions as a result. However, the reverse arrangement is also possible.
It is also preferred for the one end of the inner cable of the Bowden cable to be fixed to a stationary backrest part and for the associated end of the sleeve of the Bowden cable to be fixed to the guide receiver. A reverse arrangement is also possible here. The other end of the sleeve of the Bowden cable is in particular fixed to a stationary part of the backrest adjustment system and the other end of the inner cable is fixed to a part of the backrest adjustment system which is movable with the backrest when this is pivoted forwardly, with this end of the inner cable being attached to the movable part of the backrest adjustment system in such a way that the Bowden cable is relieved when the backrest is pivoted forwardly. This means that the Bowden cable is stressed at the normal backrest position and its sleeve fixes the guide receiver in its topmost position. When the backrest is pivoted forwardly, the Bowden cable is relieved and the return element can move the guide receiver into a recessed position.
In accordance with a further embodiment of the invention, the end of the inner cable at the backrest adjustment system side is attached to a slide block which is displaceably guided between two end positions in a slide track arranged on a stationary part of the backrest adjustment system, with the slide block being moved to and fro between its two end positions by a part of the backrest adjustment system moved by the backrest when this is pivoted forwardly. A pressure element is in particular arranged at the moved part of the backrest adjustment system, said pressure element holding the slide block in its end position in which the Bowden cable is stressed when the backrest is in its upright position and successively releasing the slide block when the backrest is pivoted forwardly so that the slide block can move into its other end position.
The movement of the Bowden cable is advantageously limited by the slide track. Together with the pressure element, the advantage also results that the backrest has a freewheel mechanism during pivoting forward. That is, the backrest can be completely pivoted forwardly without any impediment by the Bowden cable even when the inward movement of the guide receiver has already been stopped. The slide block, namely, then comes to stop at its position in the slide track and the pressure element moves away therefrom. When the backrest is pivoted back, the pressure element then acts on the slide block again from a certain inclination of the backrest and moves it back into its starting position in which the Bowden cable is stressed.
This is in particular of advantage when, in accordance with a further embodiment of the invention, a path multiplier is arranged between the backrest adjustment system and the guide receiver, said path multiplier translating a small pivot angle of the backrest into a large path of the guide receiver for the headrest. With this embodiment, it can be achieved that a small forward-pivot angle of the backrest, in particular an angle of approximately 15°, already results in the complete retraction of the headrest, even when set to its highest position. It is thus reliably ensured that the headrest does not come into contact with either the vehicle roof or a visor which may possibly
Fischer Harald
Malsch Heiko
Risch Peter
Barfield Anthony D.
Lear Corporation
MacMillan Sobanski & Todd LLC
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